Patent Application
20240245819
This disclosure relates to disinfection devices, and more particularly to those for use in medical equipment.
Catheters (e.g., intravascular (IV) catheters) are fundamental to the contemporary hospital practices and are frequently implanted in critically ill patients for the administration of drugs, fluids, blood transfusion, dietary solutions, and for hemodynamic monitoring. Approximately 90% of all the patients admitted to the hospital encounter some sort of intravenous therapy during their hospital stay. The typical duration of catheter use in clinical settings like emergency rooms, operating theaters, and intensive care units (ICUs) can range from minutes to months. While acute catheters may last up to one week, others, such as hemodialysis catheters, may be used from several months to years. Of all medical devices used in hospital settings, catheters have one of the highest rates of device-related infections. The infection causing bacteria can adhere on the catheter surface and colonize to develop biofilms. The primary contact of the bacterial cells on the surface of the catheter can emanate from the patient's own skin flora which can colonize the catheter lumen, triggering the bacteria to travel from the catheter insertion site into the vasculature. In the hospital-based setting, hematogenous seeding on the catheter from another contaminated site can be another possible source of infection, and occasionally the contamination of the catheter lumen occurs because the infusate itself is contaminated. These are predominant sources of morbidity and mortality in patients contributing to conditions like catheter related blood stream infections (CRBSIs) (e.g., bacteremia and sepsis).
Each year the occurrence of CRBSIs in the United States alone is estimated to be more than 250,000 incidences with a mortality rate of approximately 35%, with costs of approximately $2.3 billion. Catheter-related infections are increasing, especially due to the formation of biofilms. When a catheter becomes contaminated, the resultant solution is initiation of antibiotic lock therapy, and removal, and replacement of the catheter. In some critical cases, surgery may be required. Bacteria protected within biofilms require up to 1,000 times more dosage of antibiotics than their free floating (e.g., planktonic) counterparts. This heavy dosage can increase the possibility of antibiotic resistance across the bacterial species, engender economic burdens, and present a threat to native beneficial bacteria and other healthy organs of the body.
Therefore, there is an urgent need for the efficacious and harmless approaches that can not only handle the emergence but also the propagation of pathogenic microorganisms. To overcome this issue and enhance the bactericidal effect of medical devices, scientists have utilized different approaches that employ antimicrobial agents in the medical-grade polymers such as doping of silver in catheters, antiseptic solutions, peptides, and enzymes that can thwart the replication of bacteria or increase the susceptibility of antibiotics. Despite all these efforts, CRBSIs still remain one of the biggest concerns pertaining to biomedical devices.
Disclosed herein are disinfection inserts comprising a fiber optic and a polymer surrounding at least a portion of the fiber optic. The polymer comprises a NO donor molecule that is releasable upon illumination of the polymer by the fiber optic. The disinfection inserts can be inserted into tubing, catheters, and/or extracorporal devices and illuminated to release NO from the polymer. The released NO contacts and inactivates pathogens on or within the tubing or catheter. The disinfection insert can be configured for removable attachment to the tubing or catheter, such that it can be periodically replaced. Furthermore, the disinfection inserts, and specifically the fiber optic, can be placed in optical communication with a controllable light source. The intensity and wavelength of the light from the light source can be varied to change the flux of NO from the disinfection insert. The light source can be controlled by a light source controller that is wirelessly or electrically coupled to the light source.
Disinfection systems disclosed herein include a disinfection insert including a fiber optic and a polymer surrounding at least a portion of the fiber optic. The disinfection insert is configured to extend within a lumen of a medical tubing. The polymer includes a nitric oxide (NO) donor molecule. Some embodiments of the disinfection systems further include a light source in optical communication with the fiber optic of the disinfection insert. The disinfection insert can be illuminated by the light source. In the illuminated state, the disinfection insert releases NO into the catheter lumen. In some implementations, the catheter is an indwelling catheter. Some embodiments further include a light source controller.
In some embodiments, the disinfection insert further includes a fastener configured to removably attaching the disinfection insert to a medical tubing. The fiber optic can extend the length of the fastener. In some embodiments, the fastener can include a flush port. In some embodiments, the light source includes a coupling for attachment to the fiber optic. Certain implementations may enable the light source to be removably attached to the disinfection insert. In some embodiments, the fiber optic is a side glow fiber optic.
In some embodiments, the polymer is silicone rubber. The polymer can be, for example, a siloxane-based polyurethane elastomer or a thermoplastic silicone-polycarbonate urethane. The polymer can be coated directly onto the fiber optic, or the polymer can be a tube defining a space between an interior surface of the tube and the fiber optic.
In some embodiments, the NO donor molecule is an S-nitrosothiol (RSNO). In some embodiments, the disinfection insert releases NO at a flux between 0.1×10−10 mol cm−2 min−1 and 100×10−10 mol cm−2 min−1.
In some embodiments, the light source delivers light of wavelengths ranging from 200 nanometers to 700 nanometers, and/or of variable intensity. The light source can include a battery, in some implementations. The light source controller can be configured to control the wavelength and/or intensity of light from the light source. In some implementations, the light source controller is coupled to the light source via wireless communication. In some implementations the light source controller is electrically coupled to the light source.
Methods of making a disinfection insert includes incorporating (e.g., impregnating) the NO donor molecule into the polymer and coupling the fiber optic to the polymer. In some embodiments, coupling the fiber optic to the polymer includes dipping a portion of the fiber optic into a liquid form of the polymer, such that the polymer coats at least a portion of the fiber optic. In some embodiments, coupling the fiber optic to the polymer comprises attaching a solid form of the polymer to the fiber optic such that the polymer surrounds at least a portion of the fiber optic.
Methods of making the disinfection insert can include coupling a fastener to the disinfection insert, the fastener being removably attachable to a tubing, catheter, and/or extracorporeal device. The methods further include placing the fiber optic into optical communication with a light source, for example, by attaching the fiber optic to a coupling on the light source.
In the methods of making the disinfection insert, the step of incorporating an NO donor molecule into the polymer can include incorporating an RSNO into the polymer (for example, by soaking a solid form of the polymer in a solution comprising an RSNO, by mixing an RSNO into a liquid form of the polymer, or by covalently bonding an RSNO to the polymer backbone). The methods can include incorporating combinations of NO donor molecules, or combinations of RSNOs, into the polymer.
Methods of disinfecting a tubing include steps of inserting an elongated disinfection insert into a lumen of the tubing, illuminating the disinfection insert, releasing NO from a polymer of the disinfection insert, contacting pathogens on or within the tubing with the NO from the polymer, and inactivating at least a portion of the pathogens on or within the tubing via contact with the NO. The NO can inactivate pathogens within both the lumen of the tubing and within the walls of the tubing (by diffusion). In some embodiments, the tubing can be a part of a medical catheter. In some embodiments, the tubing can be part of an extracorporeal medical device. In some embodiments, the extracorporeal medical device is one of an endotracheal tube, a wound dressing or wound patch, a photodynamic therapy device, a cardiopulmonary bypass device, a hemodialysis device, a medical port, a feeding tube, or an intestinal tube.
Some example methods include a step of fastening the disinfection insert to an end of the tubing. The disinfection insert may be replaceable in some examples, such that the method further comprises unfastening the first disinfection insert from the end of the tubing and replacing it by fastening a second disinfection insert to the end of the tubing. Some example methods of disinfecting a tubing can include attaching the disinfection insert to a coupling on a light source.
The methods of disinfecting a tubing can further include a step of activating a light source that is in optical communication with the disinfection insert. In some embodiments, the disinfection insert includes a fiber optic, and illuminating the disinfection insert comprises illuminating the fiber optic. Illuminating the fiber optic causes illumination of an NO donor within the polymer. In some embodiments, the polymer includes a RSNO, and the step of releasing NO from a polymer comprises releasing NO from the RSNO.
Some methods of disinfecting the tubing further include a step of varying a flux of NO from the polymer by changing an intensity of light from the light source, and/or a wavelength of light from the light source. The NO from the polymer can be released at a flux between 0.1×10−10 mol cm−2 min−1 and 100×10−10 mol cm−2 min−1. In some configurations, the light source is controlled by a light source controller. In some configurations, the light source is controlled wirelessly.
Various objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the detailed description taken in conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawings are not necessarily drawn to scale.
Nitric oxide (NO) is an innate signaling diatomic molecule utilized by the body's defense systems for fighting infection-causing microorganisms, preventing platelet activation, reducing localized and chronic inflammations, and enhancing wound healing. Endogenous synthesis of NO in the body occurs via nitric oxide synthase (NOS) enzymes which convert the amino acid L-arginine into citrulline and NO. Considering the potential benefits of endogenous NO, various studies have been designed that can utilize these benefits synthetically by either incorporating/impregnating the NO donors in the polymer matrix that will release their NO payload or using a generation mechanism to stimulate the release of endogenous NO in blood. Nitric oxide donors like S-nitrosothiols (RSNO) incorporated into a polymer substrate can mimic endogenous NO release levels, such as endothelial cells that release NO at a surface flux of 0.5−4×10−10 mol cm2 min−1 to prevent platelet activation and adhesion. Macrophages and neutrophils utilize NO synthesized via the inducible nitric oxide synthase (iNOS)>1 microMolar NO which demonstrates antimicrobial activity by promoting biofilm dispersal and preventing the adherence of planktonic bacteria.
NO can be loaded into polymeric substrates and released in a tunable, controlled manner using a variety of triggering mechanisms. To enhance the NO payload and extend lifetime of NO release, several distinct frameworks have been developed as NO-releasing or NO-generating mechanisms at the polymer interface. Such engineered polymer surfaces that can either release or generate NO have included: polymers with physically dispersed NO donors, polymers with NO donors covalently bound to the polymer backbone, and polymers that include metal catalysts that generate NO from endogenous RSNO species. The RSNO donors like S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO) have been recognized to have extended storage capacity in crystallized form and can emit NO either photochemically, thermally by heat, light or metal ions (Cu2+, Se, Zn etc.). Strategies to modulate the levels of NO by dip coating the NO-releasing matrix with a hydrophobic polymer layer such as CarboSil, silicone, E2As and PVC have been developed to prevent leaching of NO donor. Although these approaches demonstrate advantageous biocompatibility properties, eventually the NO reservoir will be depleted which limits the functional lifetime for long-term catheter applications. It has been reported that RSNOs and RSNO-based polymers can photocatalytically release their NO payload. The characteristic absorption maxima for the RSNOs occurs at wavelengths 340 nm and 520-590 nm with corresponding to n→π* electronic transition of S—NO functional group that have been primarily associated with their decomposition.
Another approach of addressing medical device infections with light has been with the use of UVC or photodynamic therapies. It has been well established that the blue light holds great potential with respect to killing infection causing microorganisms. Staphylococcus aureus is the predominant bacterial strain associated with CRBSI arising from IV catheters, with a mortality rate ranging from 20%-30%. The susceptibilities of S. aureus and E. coli to photodynamic inactivation by visible light have been previously reported. Furthermore, UV irradiation from LEDs in polymer tubes can be used to destroy bacteria and other microbes. However, direct UVC exposure can cause undesirable effects ranging from inflammation and premature aging to serious burns and cancer.
Referring generally to the figures, a catheter disinfection insert is shown that overcomes the aforementioned limitations of NO and light-mediated microbe killing. The catheter disinfection insert, also generally referred to as “the insert,” includes a side glow fiber optic surrounded by a NO-releasing polymer, creating a device that can be inserted into a medical catheter, or any type of tubing for that matter, to prevent and eradicate viable pathogens. NO has broad-spectrum disinfection activity against bacteria, virus, fungus, and parasites. In some examples, the insert can be left in an indwelling catheter in order to treat and prevent infections that might otherwise occur on catheter surfaces. For example, when the catheter is not in use by clinicians for blood draws or infusions, it could be filled with a saline lock solution and the insert. The insert could be illuminated, constantly or periodically, in order to kill pathogens on the interior surfaces of the catheter. Furthermore, the device could be utilized to disinfect other luminal medical devices like endotracheal tubes, wound dressing bandages, access ports, dialysis or cardiopulmonary bypass machines, for example.
Certain indwelling catheters have interior surfaces coated with antimicrobial agents. The disinfection insert disclosed herein is an improvement because, unlike coated catheters, the insert can be removed from the catheter and replaced periodically as needed upon depletion of the NO from the polymer. This negates the need to replace the entire catheter. Advantageously, the insert can also be disposable. Accordingly, the insert may also be referred to herein as a disposable catheter disinfection insert (DCDI).
Turning first to
Referring now to
Insert 1 may be removably attached to the proximal end of the catheter 17 by a fastener 19, in some examples. The fastener 19 advantageously enables insert 1 to be replaced. In the aspect of
Turning briefly to
Light source 3 is in optical communication with fiber optic 11. In the aspect of
In some embodiments, light source controller 18 is configured to control the wavelength of light emitted from light source 3, the intensity of light emitted from light source 3, or both. In some embodiments, light source controller 18 can be used to program the duration of time light source 3 will be activated, or to otherwise set temporal programs that vary the wavelength and/or intensity of light emitted from light source 3 in a pre-determined pattern. In the aspect shown in
In some embodiments, light source controller 18 implements a mobile phone application. In some such, light source controller 18 may include at least one processor and a memory that can store instructions (e.g., software) for execution by the at least one processor. Because the at least one processor and memory are internal to light source controller 18, they are not explicitly shown in
Fiber optic 11 is a side emitting, or side glow, fiber optic, with cladding that enables partial escape of the light along the length of fiber optic 11.
As shown in
Polymer 13 is loaded with a NO donor molecule to release nitric oxide. In some embodiments, as shown in
As examples, a derivative may have an alkyl group attached to the free carboxyl group of SNAP and/or may have a longer alkyl (i.e., longer than acetyl) attached to the amine group of S-nitrosopenicillamine. As an example, an ester linkage may be formed between the desired alkyl group and the free carboxyl group of SNAP. As another example, a long chain alkyl (including from 4 to 10 carbon atoms) may replace the acetyl group of SNAP so that the long chain alkyl is attached to the amine nitrogen. As other examples, a sugar may be attached to the carboxyl group of SNAP (e.g., glucose-SNAP, mannose-SNAP, fructose-SNAP, etc.).
Generally, the disclosure is not limited to a specific type of polymer 13 for loading with the NO donor molecule. Various types of polymers may be suitable. For example, polymer 13 can be a silicone rubber, a siloxane-based polyurethane elastomer, a thermoplastic silicone-polycarbonate urethane, or a mixture thereof. These and other examples of NO loaded polymers are described in U.S. Pat. No. 9,566,372 and U.S. Patent Application Publication No. 2015/0366831, each of which is disclosed herein by reference in its entirety. The flux of NO from the surface of polymer 13 is preferably between 0.1×10-10 mol cm−2 min−1 and 100×10−10 mol cm−2 min−1.
In some embodiments, although not explicitly shown in the figures, light source 3 may also include a button or other user interface (e.g., a switch) for turning the device on/off. For example, light source 3 may include a button that, when pressed a first time (e.g., by a user), causes light to be emitted and, when pressed a second time, turns off the emission of light. In some embodiments, light source 3 may include a button that switches light source 3 between different operating modes. For example, the button may allow a user to select an intensity or color of light emitted. In some embodiments, light source 3 includes indicator LEDs or another type of user interface for indicating that light source 3 is turned on/off, and/or for indicating an intensity of the emitted light in embodiments where light source 3 is operable at varying intensities (e.g., brightness levels). For example, light source 3 may include at least four LEDs indicating intensities of 25%, 50%, 75%, and 100%; although, it should be appreciated that any type of indicator and any interval can be used (e.g., a digital display showing 0%-100%). In some embodiments, light source 3 may include a user interface (e.g., multiple LED indicators) for indicating a charge level of battery 23.
Methods of making insert 1, also referred to herein as a DCDI, include incorporating, loading, swelling, doping, or impregnating a NO-donor molecule into a polymer 13. In some embodiments, making insert 1 includes conjugating or immobilizing the NO-donor moiety to polymer 13. The NO-donor loaded polymer 13 is then coupled to fiber optic 11 to polymer 13. In some embodiments, however, polymer 13 is coupled to fiber optic 11 before it is loaded with the NO donor molecule. In other embodiments, polymer 13 can first be impregnated with precursor molecules and later nitrosated to form an NO-rich molecule. In some embodiments, a fastener is coupled to insert 1 for removable attachment to a catheter 7. In some embodiments, fiber optic 11 is placed into optical communication with a light source 3, for example, by attaching fiber optic 11 to a coupling 15 on light source 3.
In some exemplary methods, the NO donor molecule is mixed into a liquid form of polymer 13, and fiber optic 11 is dipped into the liquid polymer to dip coat fiber optic 11, or the liquid polymer 13 is otherwise applied to the surface of fiber optic 11. Polymer 13 may coat any desired surface area of fiber optic 11.
In some embodiments, a solid form of polymer 13 may be loaded with the NO donor molecule, for example, by soaking a solid form of polymer 13 in a solution comprising the NO donor molecule. The method of making insert 1 then further includes coupling the solid polymer 13, loaded with the NO-donor molecule, to fiber optic 11. In some embodiments, adhesives or other bonding mechanisms may be used to couple the solid form of polymer 13 to fiber optic 11. Another alternative might be to apply adhesive glue on fiber optic 11 and then place polymer 13 on the fiber (so the adhesive is in between the fiber and polymer 13, holding everything together). Again, any desired surface area of fiber optic 11 may be covered with polymer 13 in this manner.
In some exemplary methods, the NO donor molecule is conjugated to a photosensitizer molecule that is mixed in with the polymer. For example, the NO donor molecule can be covalently immobilized to a titanium dioxide (TiO2) particle. TiO2 particles can exhibit antibacterial properties once they are irradiated with light. Conjugating the NO donor molecule to a photosensitizer molecule such as TiO2 can synergistically increase the antibacterial properties of the insert due to dual action of NO and the photosensitizer molecule.
Suitable NO adducts (examples of which include discrete adducts) are generally those exhibiting capability of embedding (either by covalent attachment and/or dispersion) into the polymer matrix and exhibiting process preparation stability.
In some exemplary methods, the NO donor molecule can be covalently bound to a backbone of the polymer 13. Since SNAP is a small molecule which has the tendency to leach out from a polymer matrix (e.g., polymer 13) over time, an alternative method of conjugating polymer 13 to SNAP and coating fiber optic 11 is also described herein. Specifically, in some embodiments, hydroxy-terminated polydimethylsiloxane (PDMS-OH, 2550-3750 cst, 800 mg) is dissolved in anhydrous toluene (5 mL), which is then supplemented with (3-aminopropyl) trimethoxysilane (APTMS, 150 mg) and dibutyltin dilaurate (DBTDL, 3.4 μL). The solution is left stirred overnight. N-acetyl-D,L-penicillamine thiolactone (NAPTH, 150 mg) is then added to the reaction vessel which is stirred for an additional 24 hours. Afterwards, the reaction mixture can be nitrosated using t-butyl nitrite (1.2 mL) that was first purified with Cyclam to remove copper stabilizing agents. This final nitrosated solution can then be used for subsequent dip-coating processes, as described herein. Alternatively, in some embodiments, the final nitrosated solution can be used to produce an NO-releasing polymer (e.g., polymer 13) which is then attached (e.g., glued) to fiber optic 11.
In some embodiments, the alternative fabrication method described herein includes coating approximately 3 cm of a 10 cm fiber optic (e.g., fiber optic 11) by dipping the fiber optic in the above-discussed SNAP-PDMS solution five times, with a one minute interval between each topcoat. The coated samples are then allowed to air dry overnight at room temperature and an additional 24 hours in a vacuum desiccator (e.g., to ensure all the solvent is evaporated from the samples). The coated fiber optics are then connected to light source 3 and operated in a “continuous light mode”. In other words, light source 3 can be used to trigger the NO release from insert 1.
With the basic structure insert 1 and medical catheter system being thusly disclosed, a greater appreciation of the construction and benefits may be gained from the following discussion of the operation. It is to be noted that this discussion is provided for illustrative purposes only.
Disclosed herein are methods of disinfecting a tubing. Generally, the methods include inserting an elongated disinfection insert into a lumen of a tubing or medical catheter, illuminating insert 1, releasing NO from a polymer of insert 1, and contacting pathogens on the inner surface of the tubing with the nitric oxide from the polymer. At least a portion of the pathogens on the inner and/or outer surfaces of the tubing are inactivated (killed, disinfected, immobilized, neutralized, or otherwise reduced in virulence) via contact with the NO. For example, NO not only inactivates pathogens on the inner surface of the tubing, but NO can diffuse thought the wall of the tubing to inactivate bacteria on the tubing's outer surface. The pathogens contacted can include, for example, all kinds of bacterium, virus, fungus, and parasites. Exemplary aerobic and anerobic pathogens that can be inactivated using insert 1 include, for example, S. aureus, E. coli, S. epidermidis, P. mirabilis, S. mutans, P. aeruginosa, Klebsiella, C. albicans, MRSA, Veillonella, Actinomyces, Haemophilus, Neisseria, Vancomycin resistant enterococcus, Bacillus anthracis, Salmonella typhimurium, influenza virus, parasites like helminth S. mansoni, Leishmania donovani, and various mycobacterium. However, this list is not meant to be limiting-NO has broad spectrum activity and this is just a brief list of example pathogens that NO has been reported to kill.
The method examples given in this disclosure generally describe medical tubing and catheters. The methods are especially advantageous for indwelling catheters or tubing of extracorporeal medical devices. Example medical devices that may benefit from the use of insert 1 include, but are not limited to, intravenous catheters, urinary catheters, insulin cannulas, wound healing devices (e.g., wound dressing or wound patch), peritoneal dialysis catheters, hemodialysis catheter, feeding tubes, a photodynamic therapy device, intestinal tubes, cardiopulmonary bypass device, and the like. However, the methods are adaptable to tubing used in other industries. For example, a disinfection insert such as those described herein could be used to disinfect piping transporting non-biological fluids.
In some examples, the methods include fastening insert 1 to the end of the tubing. In some embodiments, insert 1 is replaceable. For example, the methods of use can include unfastening the first disinfection insert from the proximal end of the tubing and replacing it by fastening a second disinfection insert to the proximal end of the tubing.
The step of illuminating insert 1 can include activation of a light source that is in optical communication with insert 1. For example, insert 1 can include a fiber optic in optical communication with the light source. Illumination of the light source illuminates the fiber optic, which illuminates an NO donor within the polymer, which in turn releases the NO from the polymer. In some examples, the NO donor is a RNSO. Some methods of use include a step of attaching insert 1 to a coupling on a light source.
In some examples of the methods of use, NO is released from the polymer at a flux between 0.1×10−10 mol cm−2 min−1 and 100×10−10 mol cm−2 min−1. In some example methods of use, the intensity of light from the light source can be changed to vary a flux of NO from the polymer. In some examples, the wavelength of light from the light source can be changed to vary a flux of NO from the polymer.
In some embodiments, light source 3 can be controlled by wireless communication (for example, using a remote control, or a remote user interface on a computer or a mobile phone). For example, the light source can be controlled using software that acts as a light source controller (e.g., light source controller 18). As described above, light source controller 18 can, for example, be programmed to gradually increase light intensity so that the NO flux remains relatively constant over time until depletion. In some examples, the manufacturer or clinician has access to light source controller 18, to control the NO levels. The methods of use can include protections against patient tampering. The protections can be embedded within the light source controller software, for example. Furthermore, patients could be trained to replace the insert at certain time intervals in long-term situations.
Materials: N-Acetyl-D-penicillamine (NAP), sodium nitrite, L-cysteine, sodium chloride, potassium chloride, sodium phosphate dibasic, potassium phosphate monobasic, copper (II) chloride, ethylenediaminetetraacetic acid (EDTA), tetrahydrofuran (THF), and sterile phosphate buffer saline powder with 0.01 M, pH 7.4, containing 0.138 M NaCl, 2.7 mM KCl, were purchased from Sigma Aldrich (St. Louis, MO). Methanol, hydrochloric acid, and sulfuric acid were obtained from Fisher Scientific (Hampton, NH). Helixmark® silicone tubing-silastic material (60-011-06) were purchased from VWR (Radnor, PA). A 12V 1.5 W LED light source (Rayauto) and LED BLE Bluetooth 4.0 software (Guixing Tan) were used for the light studies. All aqueous solutions were prepared using deionized water. Phosphate buffer saline (PBS) 0.01M with 100 Micromolar EDTA was used for all material characterization and NO analyzer studies. Dulbecco's modified Eagle's medium (DMEM) and trypsin-EDTA were purchased from Corning (Manassas, VA20109). The Cell Counting Kit-8 (CCK-8) was purchased from Sigma-Aldrich (St. Louis, MO). Penicillin-Streptomycin (Pen-Strep) and fetal bovine serum (FBS) were obtained from Gibco-Life Technologies (Grand Island, NY). The bacterial strains Staphylococcus aureus (ATCC 6538) and E. coli (ATCC 25922) were obtained from American Type Culture Collection (ATCC). All the buffers and media were sterilized in an autoclave at 121° C., 100 kPa (15 psi) above atmospheric pressure for 20 minutes prior to the biocompatibility experiments.
S-nitroso-N-acetvlpenicillamine Synthesis: The S-nitroso-N-acetylpenicillamine (SNAP) synthesis procedure was adapted from previously a published report with a slight modification. Briefly, NAP and sodium nitrite were taken in equimolar amounts and dissolved in a 2:3 ratio of water and methanol. To the above mixture, 0.7 and 1.6 M of H2SO4 and HCl were added, respectively followed by stirring for 10 minutes at room temperature. The beaker was shielded from ambient light, puffed with mild air, and incubated in an ice bucket for 8-10 hours. After incubation, filter paper was used to collect the SNAP crystals into a Buchner funnel using suction filtration. SNAP was then cleansed with ice-cold deionized water and placed in a vacuum desiccator overnight to remove the surplus solvent. Samples were shielded from light throughout the process and the purity of SNAP crystals (>90%) was verified using the chemiluminescence NOA and UV-vis calibration curve at 340 nm.
SNAP Impregnation: To impregnate the silicone rubber (SR) tube with SNAP, a stock solution of SNAP and THE (125 mg mL−1) was prepared. A 3 cm long Helix silastic SR tube with an inner diameter of 0.058 inches was incubated in SNAP-THF solution for 24 hours in the dark at room temperature. After 24 hours, SNAP impregnated tube (SR-SNAP) was removed from the solution and dried overnight in a vacuum desiccator protected from light. All samples were cleaned with PBS to remove excess SNAP crystals from the outer surface and lumen of the impregnated tube before conducting any further experiments.
Determining weight percentage SNAP using UV-vis: The amount of SNAP impregnated in the SR-SNAP tube was quantified using a UV-vis spectrophotometer (Cary 60, Agilent Technologies). For this, first the mass of each SR-SNAP sample was recorded using an analytical balance (Mettler Toledo™ XS105DU, Columbus, OH). Each SR-SNAP sample was soaked in THF for 30 minutes to extract all the SNAP impregnated into the SR tube. The sample appeared clear after incubation in the THF, indicating all SNAP had been extracted into the THF. The SNAP extracted solution was evaluated by UV-vis spectroscopy at 340 nm wavelength. The molar absorptivity of SNAP in THE at 340 nm was determined to be 909 M−1 cm−1. The weight percentage (wt %) of SNAP loaded is reported as milligrams of SNAP loaded per milligram of tube.
Fabrication of the disinfection insert: A disposable catheter disinfection insert (DCDI) was produced using a 2.9 cm SR-SNAP tube mounted on a 7 cm segment of 1.5 mm diameter PMMA side glow optical fiber (Huaxi). As described herein, DCDI may be the same as, or functionally equivalent to, insert 1, described above. A layer of aluminum foil was wrapped around the rest of the optical fiber followed by a layer of parafilm to only allow light to emit from the SR-SNAP section of the DCDI. The DCDI samples were attached to a 12V 1.5 W LED light source (Rayauto) and controlled via Bluetooth using a mobile phone application.
Light emission spectroscopy measurements: To determine the wavelength of light emitted by LED light source, a wireless spectrophotometer (PS-2600, PASCO Scientific) with a detection range of 380-950 nm was utilized. The light detecting fiber optic cable was held in place with a clamp and DCDI samples were exposed to the detector and wavelength of light was recorded with four different colors (red, blue, green and white). Studies with light were done in the absence of ambient light to ensure only desired lights are being characterized.
Photoinitiated NO release: The NO release from the SNAP impregnated samples with light (SNAP-light) and without light (SNAP) was quantified using a gold standard chemiluminescence NO analyzer (NOA) 280i (Zysense, Frederick, CO) under nitrogen atmosphere. Experiments were performed at physiological temperature (37° C.) both in dry (to validate the effect of light on NO release) and in the presence of PBS (emulating the ‘real-world’ application). The NO release from the samples is normalized to the surface areas and presented as moles min−1 cm−2.
NO release vs. light color: In order to optimize the light from DCDI, samples were placed in an NOA sample cell at 37° C. connected to the LED light source. Using the mobile phone application, the LED light source was set to emit light at 100% intensity and the NO flux was recorded as the light color was adjusted. Four different light colors (white, blue, green, and red) were tested for their NO release.
24 Hour NO Release: The samples were immersed in PBS with EDTA (7.4 pH) at the physiological temperature of 37° C. in an amber NOA sample cell. For the SNAP-light samples, the LED light source was set to emit white light at 100% intensity. 24 hour NO release profiles for the DCDI samples were recorded using 0% (light off), and 100% white light intensity. The NO release was quantified by averaging the NO release during the first 2 hours of the experiment and at the 24-hour time point.
Tunable NO Release: The SNAP-light samples were placed in an NOA sample cell at 37° C. protected from ambient light. The LED light source was set to emit white light from the connected fiber optic and the NO flux from samples were recorded as the light intensity was adjusted using smartphone application. Starting without light (in dark), the intensity of light was increased in 25% increments until 100% intensity was reached. The light intensity was then decreased by 25% until 0% to show the strong control over NO levels. The NO release for each step was allowed to plateau before changing to the next step.
Determination of SNAP leaching: The amount of SNAP leached from samples SR-SNAP (light off) and SNAP-light (100% light intensity) was determined by a UV-vis spectrophotometric method. Each sample was incubated in 10 mM PBS, pH 7.4, with 100 microMolar EDTA at 37° C. for 24 hours. The soaking buffer was evaluated for SNAP concentration at 2, 4-, 6-, 8- and 24-hour timepoints. The molar absorptivity of SNAP in 10 mM PBS, pH 7.4, with 100 Micromolar EDTA at 37° C. was determined as 1072 M−1 cm−1 at 340 nm. Samples were stored at 37° C. throughout the duration of the experiment. Results were analyzed by calculating SNAP concentration from each sample, normalized by the surface area of DCDI.
In Vitro Antibacterial Properties: 4 hour Bacterial Adhesion Assay: The antibacterial activity of DCDI was examined against S. aureus and E. coli in terms of viable bacterial adhesion on the catheter surface. All samples (SR, SR-light, SNAP, and SNAP-light; n=3 each) were exposed to the bacterial solution with the final OD600 of bacteria ranging between 106-108 CFU mL−1 for 4 h at 150 rpm at 37° C. to maintain the chronic infection conditions. After 4 hours, bacteria adhered on the DCDI surface were extracted, diluted, and plated using a spiral plater (Eddy Jet 2, IUL Instruments) (50 microLiters). Viable colony forming units (CFU) were determined after 24 hours of incubation at 37° C. using an automated bacteria colony counter (Sphere Flash, IUL Instruments). The CFU's on the DCDI (SNAP-light) and controls were normalized by surface area of the samples and percentage of reduction in bacterial viability was determined by the following equation.
In Vitro Ability of DCDI to treat established microbial infections on catheter surfaces: To evaluate the efficacy of DCDI in disinfecting the infected catheter, an in vitro assay was developed using S. aureus bacteria. S. aureus was grown overnight in an LB media following the same procedure as the 4-hour bacterial adhesion assay, above. Then, 3 mL of bacterial suspension (0.1 OD) was used to expose the model CVC catheter (Dow Corning 60-011-09 Helix silicone tubing) 3 cm long; such that both inner lumen and outer surface of the catheter were exposed to bacteria. Samples were exposed in the media for 24 hours in LB medium at 37° C. (static conditions). Nutrient media in the tubes was replaced periodically to keep the supply of nutrients stable. After 24 hours, samples were taken out from media containing bacteria and briefly rinsed to remove any unadhered cells on the catheter tubing. Later, DCDI samples with 100% white light intensity and control samples were then inserted into the infected catheter tubing and incubated in PBS pH 7.4 for 4 hours at 37° C. under static conditions. The control samples contained no NO-releasing DCDI, just a plain SR tubing mounted on fiber optic inserted into the bacteria infected catheter. Samples were taken out after incubation and bacteria remaining on the catheter surface were enumerated using the same protocol as the 4-hour bacterial adhesion assay, above.
In Vitro Cytocompatibility Study: Leachate Preparation: All test and control groups SR, SNAP, light, and SNAP-light samples (n=3) each were first cleaned with ethanol and UV-sterilized for 30 minutes. Next, DMEM media (1 mL) was added to the samples to collect the leachates in the solution by following the ISO standards (ISO10993-5:2009 Test for in vitro cytotoxicity). Vials were covered in aluminum foil to prevent from ambient light and incubated for 24 hours at 37° C. After 24 hours, the samples were removed, and the leachates were used for the further analysis.
In Vitro Cytocompatibility Study: Cell Viability: A cell culture treated 96-well plate was used to seed 3T3 mouse fibroblast cells (5000 cells/mL) in each well and incubated in a humidified incubator at 37° C., 5% CO2 for 24 hours. Later, leachate samples were exposed to the cells (100 microLiters) and incubated for another 24 hours to let the leachates act on the cells. The cytocompatibility study was conducted in compliance with the ISO 10993 standard using a CCK-8 cell viability kit following the manufacturer's instructions (Sigma, OH). To each of the wells CCK-8 solution was added (10 microLiters) and incubated for 1 hour. The absorbance (abs) of the samples was recorded at 450 nm wavelength using microplate reader (Cytation 5 imaging multi-mode reader, BioTek). Results from the experiment are reported as relative cell viability of test group normalized to control (cells in media) using the following equation:
Statistical Analysis: All results in the study are presented with sample size n≥3. Data are all reported as mean±standard error of mean (SEM). Statistical significance between the sample types was determined using student's t-test. To ascertain the significance of results, value of p<0.05 was used to draw the comparison between the test (light, SNAP, SNAP-light) and control groups (SR).
Sterilization of SNAP impregnated tubing: Sterilization of medical devices is an important process for decontaminating the surfaces before in vivo application. Ethylene oxide and ultraviolet light sterilization methods were tested on the DCDI. For ethylene oxide sterilization, the NO releasing insert were packaged into the sterilization pouch and exposed to EO under AN 74i Anprolene EO gas sterilizer (Anderson Sterilizers). The sterilizer was operated at room temperature (between 68-91° F.) with a Humidichip to ensure at least 35% humidity was achieved. Samples were sterilized for 12 hours with 2 hours of purging. For UV light sterilization, SR-SNAP samples were sterilized with UV-light under biosafety cabinet administered by REDISHIP Purifier® Logic®+Class II A2 Biosafety Cabinets, Labconco® for 30 minutes. All the samples (n=4) were pre-weighed and suspended in THE (30 minutes) to extract all the SNAP from the polymer. The amount of SNAP remaining in the SR-SNAP tubing after sterilization process was compared to fresh samples using UV-vis spectroscopy by measuring the absorbance of SNAP extracted in THE at 340 nm wavelength. The results of the study are reported as normalized values to initial weight percent of SNAP (weight of SNAP/weight of polymer).
It has been previously reported that SNAP incorporation/impregnation into various polymers, like polyurethanes and silicone elastomers, gives long-lasting and controlled NO release, with enhanced shelf-life stability, ability to withstand sterilization, low rates of SNAP leaching, and photosensitivity. The wt % SNAP impregnated in the SR-SNAP samples was quantified using a UV-vis spectrophotometer. The solubility of SNAP in THE allowed the full extraction of the impregnated SNAP in each sample. As shown in
To confirm the wavelength of light emitted by the LED source, a PASCO wireless spectrometer optical probe was utilized. The wavelength of light was determined at four different colors of light. As shown in
Side glow fiber optic is thin, flexible, and illuminating. Side glow fiber optic was chosen over end glow fiber optic to illuminate the full length of SNAP tube, ensuring the effectiveness of eradicated bacteria along the entire length of DCDI inserted within a catheter. The thin, flexible nature of the fiber optic and a tubular scattering factor enables the light to uniformly disseminate through the catheter lumen.
Referring now to
Real time control of NO Release: It would be useful to be able to dynamically control NO level depending on the biomedical application. For instance, at the time of implantation, the catheter may need a higher level of NO to prevent bacterial colonization on the device surface. However, over time the same device may need lower levels of NO to maintain the biofilm-free state of the device. Similarly, a significantly contaminated device surface may require very high levels of NO to disinfect and eradicate the pre-established biofilm on the catheter surface. Tight control of NO release can be achieved by exploiting the photosensitivity of NO donating compounds that can tune the NO release in response to intensity and wavelength of light.
The ability to control the release of NO by changing the light intensity was assessed by increasing and decreasing the white light intensity in 25% intervals. To avoid the interference of leached SNAP in buffer conditions, a dry state at physiological conditions was used to study the influence of white light on DCDI at different light intensities. Referring generally to
Real time NO Release: To confirm if the DCDI could be applied to disinfect in the buffer environment, the NO release from the DCDI was measured under physiological conditions (37° C. in PBS buffer) using chemiluminescence for 24 hours at 0% (dark), and 100% white light intensity. Results confirmed that DCDI submerged in PBS could still be set alight via the mobile phone application for at least 24 hours, at levels equivalent to the data presented in
Although the testing was done only up to 24 hours, reports have shown that SNAP loaded SR can have prolonged NO release. Overall, the DCDI was able to closely simulate the levels of NO released by endothelium (0.5−4×10−10 mol cm−2 min−1) in the body which is responsible for important biological functions such as reducing inflammation and fibrosis, killing various microbial species (bacteria, fungus, viruses), inhibiting disrupting and dispersing microbial biofilm formation, preventing platelet activation, reducing clotting and thrombosis. The NO release levels achieved here corroborate with previously reported studies that include impregnation of silicone-based polymers for biomedical applications. Nitric oxide in the gaseous form is known to have a very short half-life. NO donors blended, conjugated, or impregnated in the polymer matrix for therapeutic and targeted NO release exhibit exceptional stability and biocompatibility. Wo et al. have shown the stability of SNAP during storage in different polymeric matrix that revealed the stability of SNAP for up to 8 months. The excellent storage stability can be attributed to the intramolecular hydrogen bonding between the SNAP crystals within the polymer-crystal composite.
RSNO's have been known to decompose via heat, light, metal and chemical-based mechanisms, all of which exhibit catalytic activity that trigger NO release from the donors. Even today, RSNO-based polymeric devices have a major limitation due to the leaching of NO donor which not only compromises the duration of NO delivery but also at times can result in unfavorable body reactions. Impregnating the NO donor SNAP into hydrophobic polymers like SR has been demonstrated to regulate leaching, which consequently prolongs the NO release from the polymer. Due to the intramolecular hydrogen bonding between SNAP molecules and the low water uptake of hydrophobic polymers, SNAP dissolution and dissemination out of the polymer is highly contained.
To quantify the amount of SNAP leached, both SNAP (dark 0% light) and SNAP-Light (100% white light) samples were soaked in PBS-EDTA at 37° C. for 24 hours. The soaking buffer was collected at 2, 4, 6, 8 and 24-hour timepoints and absorbance was recorded using UV-vis spectroscopy. After 24 hours, 84.61±5.32 and 35.83±2.04 micrograms cm2 of SNAP was detected from SNAP and SNAP-light samples, respectively (
Lower quantities of SNAP leach out of the polymer and eventually degrade into N¬-acetyl-D-penicillamine (NAP), and NAP-dimer. Any minimal leaching of SNAP, or more likely NAP (N-acetyl-penicillamine) and dimers of NAP, ultimately hydrolyze to penicillamine. Low levels of penicillamine is not a major concern since it is an FDA approved agent used to treat heavy metal poisoning in humans. Besides, studies in the past have demonstrated SNAP to be safe at low concentrations during in vivo testing of SR-SNAP. The advantage of introducing light to the SNAP impregnated polymer is the NO release from the SNAP can be amplified by enhancing the catalytic rate of NO from the NO donating compound. As the leaching reduced, the corresponding NO release rate increased highlighting the advantages of light.
Over 1 million cases of hospital acquired infections are reported every year. About 60-70% of these infections arise from bacterial contamination and biofilm formation on the surface of medical devices, which severely compromises the durability of the medical devices and associated cost. With time, biofilm-associated pathogens are acquiring more and more resistance mechanisms against standard antibiotic treatment, leaving the conventional treatments futile. For this reason, many novel antimicrobial approaches have been proposed. Light based antimicrobial therapy is one such strategy being employed for combating biofilms on medical implants. Clinical pathogens such as S. aureus and E. coli have been proven to be vulnerable to photodynamic inactivation by the wavelengths of visible spectrum of light (400-800 nm). Similarly, photoactivation of silver and gold nanoparticles have also been explored for bactericidal efficacy. However, metal-dependent disinfection can vary by the type of metal, and for Gram positive versus Gram negative bacteria. Furthermore, metal-dependent disinfection has some cytotoxicity towards mammalian cells. For this reason, a broad-spectrum, biocompatible disinfecting device was developed in this study for eradicating both Gram-positive and Gram-negative bacteria.
The bactericidal efficiency of DCDI was evaluated against S. aureus and E. coli bacteria using a 4 hour bacterial adhesion assay. The bacterial cells adhered on the DCDI were enumerated and normalized to the surface area of the catheter to obtain viable CFU cm−2. Results from S. aureus adhesion on the synergy of SNAP-light unveiled an approximate 99.45% reduction compared to the SR control (p<0.05). As shown in
Referring also to
While the light and SNAP individually led to reductions of about 85.01 and 92.89%, results from the E. coli study showed highest reduction in viable E. coli adhesion on the surface of SNAP-light DCDI at 99.36% compared to SR control (p<0.05), as shown in
The ability of DCDI to eradicate pre-colonized bacteria on a catheter surface was characterized against S. aureus, one of the most common bacteria associated with biofilm-related infections. The S. aureus bacteria was grown till mid-log phase and exposed to model CVC catheters for 24 hours at 37° C. After 24 hours, the DCDI and the corresponding SR control was then inserted into the infected catheter to investigate the disinfecting ability. Viable bacteria remaining on the surface of the catheter were enumerated and reported as CFU cm−1 of the polymer. Referring to
Nitric oxide is known to induce biofilm dispersal across many bacterial strains, which led to its importance in emerging as therapeutic for biofilm-related infections. NO is a reactive gas with very short half-life with an ability to diffuse through the cell membranes spontaneously. Previous reports have shown that NO at lower concentrations can trigger the switch of sessile cells to free floating planktonic phenotype in bacterial cells enclosed within the biofilm. It is understood that the control of intracellular secondary messenger such as cyclic di-GMP by NO imitates the effectors which can hamper the biofilm buildup and disperse the mature biofilm. The reactive nitrogen species from NO and the superoxide ions lower the extracellular polysaccharide production which is an important intermediary component for bacterial attachment on a substratum. The role of NO in facilitating biofilm dispersion is maintained across a wide range of bacterial species.
The results from prevention of bacterial adhesion (
Over the years, eukaryotic cells have developed mechanisms for scavenging the reactive oxygen and nitrogen species which enables them to negate their influence; however, various microorganisms (bacteria and virus) remain vulnerable. The combination of SNAP and light was effective in lowering the number of viable microbial cells. Nonetheless, it is important to determine the compatibility of engineered disinfection insert towards mammalian cells for effective in vivo application. The biocompatibility of the DCDI and respective controls was verified using NIH 3T3 mouse fibroblast cells. To investigate this, SR, SNAP, light and SNAP-light DCDI samples were first incubated in DMEM media to collect the leachates in the solution. Later, the leachates were added to the cells and incubated for 24 hours at 37° C. to determine toxicity of the solutions against mouse fibroblast cells. After 24 hours, a cell cytotoxicity assay was conducted on the cells using a CCK-8 cell viability kit. Samples were read for their absorbance and data was analyzed to compare the absorbance of controls and test groups. Mouse fibroblast cells demonstrated no significant difference in the presence of the leachates from all the samples with respect to controls.
Referring now to
Medical devices must be sterilized before in vivo application, and so they must be able to withstand sterilization processes without compromising desired properties. NO donating compounds such as RSNO's are known to degrade due to their sensitivity to temperature and thermal degradation. It is therefore important to evaluate the compatibility of SNAP polymer with regularly used sterilization processes. To investigate their stability under sterilization process, samples were exposed UV-light and EO gas. Both sterilization methods were proven to be compatible with the NO releasing polymer. As shown in
Since SNAP is a small molecule and it has the tendency to leach out from polymer matrix over time, an alternative method of conjugating PDMS polymer to SNAP used to coat the fiber optic device is also described herein. Using the conjugated SNAP-PDMS, in this study, a battery-operated fiber optic light source (e.g., light source 3) was used to trigger the NO release from device. In some embodiments, the fiber optic light source emits a blue light in 450 nm wavelength spectra.
SNAP-PDMS synthesis: Hydroxy-terminated polydimethylsiloxane (PDMS-OH, 2550-3750 cst, 800 mg) is dissolved in anhydrous toluene (5 mL), which is then supplemented with (3-aminopropyl) trimethoxysilane (APTMS, 150 mg) and dibutyltin dilaurate (DBTDL, 3.4 μL). The solution is left stirred overnight. N-acetyl-D,L-penicillamine thiolactone (NAPTH, 150 mg) was then added to the reaction vessel which was stirred for an additional 24 h. Afterwards, the reaction mixture was nitrosated using t-butyl nitrite (1.2 mL) that was first purified with Cyclam to remove copper stabilizing agents. This final nitrosated solution was used for subsequent dip-coating processes, as described below.
Fabrication of second-generation disinfection insert: The NO-releasing fiber optic was developed by coating approximately 3 cm of the 10 cm long LC-connectorized Corning® Fibrance® Light-Diffusing Fiber Optic. Each sample was dip-coated with SNAP-PDMS solution five times with 1 min interval between each topcoat. The coated samples were allowed to air dry overnight at room temperature and then additional 24 h in vacuum desiccator to ensure all the solvent is evaporated from the samples. The NO-releasing samples were connected to single color light source 3 with continuous light mode for all the study. For control samples either PDMS or SNAP-PDMS were coated on fiber optic samples and operated with or without light resulting in the control samples of SR, SR-Light and SR-SNAP, respectively.
Controlling NO release from SNAP-PDMS coated insert: The nitric oxide (NO) release from SR-SNAP-Light was determined using a Zysense Nitric Oxide Analyzer 280i (NOA) which is the gold standard chemiluminescence detection system for measuring NO release in real-time. The NO released from samples was detected by the NOA in parts per billion and the flux values (moles min-1 cm-2) were normalized with the surface area of the sample. The samples were immersed in PBS with EDTA (7.4 pH) at the physiological temperature of 37° C. in an amber NOA sample cell. The ability to control the NO release from SR-SNAP-Light samples was demonstrated with light off and light on (continuous light mode) at 5 min interval. A similar study was done to evaluate the NO release from SR-SNAP and SR-SNAP-Light samples.
Antibacterial activity: The antibacterial activity of the samples was evaluated against S. aureus bacteria using a 2 h antibacterial adhesion assay. For this single isolated colony of S. aureus bacteria was inoculated in LB media and grown to mid-log phase. All samples (SR, SR-light, SNAP, and SNAP-light; n=3 each) were exposed to the bacterial solution with the final OD600 of bacteria ranging between 106-108 CFU mL−1 for 2 h at 37° C. to maintain the chronic infection conditions. After 2 h, bacteria adhered on the surface were extracted, diluted, and plated using a spiral plater (Eddy Jet 2, IUL Instruments) (50 μL). Viable colony forming units (CFU) were determined after 24 h of incubation at 37° C. using an automated bacteria colony counter (Sphere Flash, IUL Instruments). The CFUs on the samples were normalized by the length of the samples and percentage of reduction in bacterial viability was determined by Equation 1, above.
NO release properties: The ability to tightly control the NO release from the insert, fabricated with the covalently immobilized SNAP-PDMS polymer, was tested to evaluate the ability to tune and control the NO release using photoactivation by illuminating the side glow fiber optic. The light from the samples was turned on and off at 5 min interval. As shown in
The NO release from SR-SNAP and SR-SNAP-Light samples was tested by submerging the samples in PBS with EDTA, as shown in
Antibacterial activity: The bacterial cells adhered on the insert after a 2 h exposure were enumerated and normalized to the length of the sample to obtain viable CFU cm−1. Results from S. aureus adhesion on the synergy of SNAP-Light unveiled a ca. 93.62% reduction compared to the SR control (p<0.05), as shown in
The preceding description of certain examples of the inventive concepts should not be used to limit the scope of the claims. Other examples, features, aspects, embodiments, and advantages will become apparent to those skilled in the art from the following description. As will be realized, the device and/or methods are capable of other different and obvious aspects, all without departing from the spirit of the inventive concepts. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The implementation was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various implementations with various modifications as are suited to the particular use contemplated.
For purposes of this description, certain aspects, advantages, and novel features of the aspects of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed aspects, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.
Although the operations of exemplary aspects of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that disclosed aspects can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular aspect or implementation are not limited to that aspect or implementation and may be applied to any aspect or implementation disclosed. It will be understood that various changes and additional variations may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention or the inventive concept thereof. Certain aspects and features of any given embodiment may be translated to other embodiments described herein. In addition, many modifications may be made to adapt a particular situation or device to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular implementations disclosed herein, but that the invention will include all implementations falling within the scope of the appended claims.
Features, integers, characteristics, compounds, chemical moieties, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing aspects. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
Throughout this application, various publications and patent applications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this disclosure pertains. However, it should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.
As used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. The terms “about” and “approximately” are defined as being “close to” as understood by one of ordinary skill in the art. In one non-limiting aspect the terms are defined to be within 10%. In another non-limiting aspect, the terms are defined to be within 5%. In still another non-limiting aspect, the terms are defined to be within 1%.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.
The terms “proximal” and “distal” as used herein refer to regions of the medical catheter system or disinfection insert. “Proximal” means a region closer to the light source (and closer to the practitioner during a procedure), whereas “distal” means a region farther from the light source (and farther from the practitioner during a procedure).
Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.
As used herein, disinfection means killing a pathogen, immobilizing the pathogen, reducing numbers of the pathogen, neutralizing the pathogen, or otherwise reducing the virulence of the pathogen. “Pathogen” can indicate any form of bacteria, virus, fungus, or parasite.
This application claims the benefit of and priority to U.S. Provisional Patent App. No. 63/190,456, filed May 19, 2021, which is incorporated herein by reference in its entirety.
This invention was made with U.S. Government Support under Grant No. R01 HL151473 awarded by the National Institutes of Health. The U.S. Government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/030045 | 5/19/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63190456 | May 2021 | US |
