Patent Application
20150289751
There are many consumer and industrial products made from clear polymer materials where good visibility and non-obscure light transmission are highly desirable. The surfaces of such materials often come into contact with a variety of agents, including moisture, water, oils, aqueous salt solutions, acid or base solutions, and chemicals dissolved or suspended in aqueous compositions or other liquids. Likewise, a temperature differential between a polymeric surface and a warm, moist surface can lead to fogging. In addition, freezing liquids, such as water, can result in frozen deposits that are strongly adhered to the polymer surfaces. Alternatively, elevated temperatures can accelerate deleterious processes, such as corrosion or surface leaching.
Examples of transparent polymer surfaces that can be negatively impacted by the adhesion of moisture or other materials that can obscure vision and light transmission include ski goggles, swimming goggles, glasses, windows, vehicle windshields, motorcycle fairings, camera lenses, waterproof enclosures for cameras or other viewing equipment, endoscopes, smartphone surfaces, tablet computer surfaces, and the like. Even opaque polymer surfaces may be worth protecting from adhesion by moisture, water, oils, solutions, liquids or ice.
One example area where it is desirable to maintain a clear surface free of debris and fogging is through the viewing and/or illumination window of a surgical viewing instrument. For example, laparoscopic surgery, also called minimally invasive surgery (MIS), band-aid surgery, or keyhole surgery, is a modern surgical technique in which operations in the abdomen are performed through small incisions (usually 0.5-1.5 cm) as opposed to the larger incisions needed in laparotomy. There are a number of advantages to the patient with laparoscopic surgery versus an open procedure. These include reduced pain due to smaller incisions and hemorrhaging, and shorter recovery time. Laparoscopic surgery includes operations within the abdominal or pelvic cavities, whereas keyhole surgery performed on the thoracic or chest cavity is called thoracoscopic surgery. Laparoscopic and thoracoscopic surgery belong to the broader field of endoscopy.
Laparoscopy uses a thin, lighted tube put through a cut (incision) in the belly to look at the abdominal organs or the female pelvic organs. Laparoscopy is typically used to find problems such as cysts, adhesions, fibroids, and infection, but can also be used to remove and modify organs. Tissue samples can be taken for biopsy through the tube (laparoscope). Laparoscopic surgery makes use of images displayed on TV monitors to magnify the surgical elements.
There are two types of laparoscopes: (1) telescopic rod lens system, which is usually connected to a video camera (single chip or three chip) and (2) digital laparoscope where a charge-coupled device is placed at the distal end of the laparoscope, eliminating the rod lens system. Also attached is a fiber optic cable system connected to a cold light source (halogen or xenon) to illuminate the operative field. The abdomen is usually insufflated, or essentially blown up like a balloon, with carbon dioxide gas. This elevates the abdominal wall above the internal organs like a dome to create a working and viewing space.
During surgical operations, bodily fluids, blood, condensation, and the like can adhere to the observation window of the laparoscope so as to distort, obscure and degrade visibility of the surgical site. To maintain good visibility, the window typically requires frequent cleaning One common solution is to pull out the laparoscope and wipe it with a cleaning cloth. Another is to wipe it on an internal organ such as the liver. Yet another involves keeping the laparoscope warm to prevent condensation, such using a scope heater prior to insertion into the body cavity. Some laparoscopes are equipped with cleaning mechanisms, such as a wiping system described in U.S. Pat. No. 7,959,561, a trocar or hub that cleans the laparoscope each time it is pulled out and reinserted through the trocar or hub, or air flow mechanism that prevents condensation by blowing air against the tip.
While physically cleaning the laparoscope is effective to ensure a clean and clear observation window, it requires the surgeon to remove the laparoscope from the surgical site and/or requires two hands. In either case, the surgery is interrupted, lengthening the time of the procedure. Self-cleaning mechanisms, though convenient and essentially automatic, are less effective in ensuring a clean and clear observation window (e.g., because they typically only prevent fogging or remove condensation but do not effectively remove blood and tissue debris).
Disclosed herein are polymeric articles that include a nanoscopically and/or microscopically rough surface formed on at least a portion of the article. Methods of using and making such articles are also disclosed. In one embodiment, covers for use with a surgical viewing instrument that include the nanoscopically and/or microscopically rough surface are disclosed. A variety of surgical viewing instruments such as, but not limited to, laparoscope, endoscopes, capsule endoscopes, pill cameras, and surgical microscopes are routinely used for visualizing and/or illuminating a medical procedure site. However, during surgical operations, bodily fluids, blood, condensation, and the like can adhere to the observation window of the surgical viewing instrument(s) and distort, obscure and degrade visibility of the surgical site. For example, the window can fog up due to the temperature differential between the surgical viewing instrument and the warm, humid environment in and around the body. In addition, smoke, blood, and tissue debris from ablation, cutting or cautery can adhere to the window. Spraying and smudging by blood and tissue debris can also obscure vision. The nanoscopically and/or microscopically rough surface is configured to shed and/or incorporate into a thin, substantially uniform film such droplets, fogs, and debris for providing clearer and less obstructed vision at a surgical, diagnostic or procedure site.
In an embodiment, a cover for use with a surgical viewing instrument for providing clearer and less obstructed vision at a surgical, diagnostic or procedure site is disclosed. The cover includes a cover configured for placement over at least a portion of a surgical viewing instrument, at least a portion of the cover being transparent to light, and a nanoscopically and/or microscopically rough surface formed on at least a portion of the cover that provides a clearer and less obstructed view of a surgical, diagnostic or procedure site through the surgical viewing instrument. Also disclosed are methods of making and using such covers.
According to one embodiment, the cover includes an elongate tubular member that at least partially encloses a surgical viewing instrument (e.g., a laparoscope) during use. The nanoscopically and/or microscopically rough surface may be positioned on the distal tip and/or sidewall of the elongate tubular member. The elongate tubular member may further include a rigid hub attached to a proximal end of the elongate tubular member to provide added strength and gripping ability.
Depending on surface chemistry, the nanoscopically and/or microscopically rough surface can be at least one of a highly hydrophobic, highly oleophobic, or highly hydrophilic surface. According to one embodiment, the nanoscopically and/or microscopically rough surface comprises a highly hydrophobic composition that repels water and other hydrophilic substances. The highly hydrophobic composition may comprise nanoparticles held to the cover by one or more types of silanes and preferably cross-linked to increase strength and prevent hydrolysis during use. The highly hydrophobic composition may further comprise a hydrophobic surface modifying agent to maximize hydrophobicity.
The highly hydrophobic composition advantageously repels water as a result of surface tension and preferential self-adhesion of water molecules to themselves rather than the highly hydrophobic composition. The highly hydrophobic composition can be formulated so as to cause water or protein-based droplets to have a high surface angle relative to the polymer surface of the cover (e.g., at least about 135°, 140° or 150°). The highly hydrophobic composition is formulated so as to cause water or protein-based droplets to have a low shedding angle or hysteresis angle relative to the sheath (e.g., less than about 30°, 15° or 10°). The highly hydrophobic composition can be formulated so that the cover does not decrease light transmittance through the cover by more than about 20%.
According to another embodiment, the nanoscopically and/or microscopically rough surface comprises a highly oleophobic composition that repels oils and other non-polar substances. The highly oleophobic composition may comprise nanoparticles held to the cover by one or more types of silanes and preferably cross-linked to increase strength and prevent hydrolysis during use. The highly hydrophobic composition may further comprise an oleophobic surface modifying agent (e.g., a fluorinated compound) to maximize oleophobicity.
According to yet another embodiment, the nanoscopically and/or microscopically rough surface comprises a highly hydrophillic composition that may readily absorb water and water-based liquids and thereby form a substantially uniform aqueous layer on the cover. Such a substantially uniform aqueous layer may, for example, prevent fogging. Such a highly hydrophilic composition may also be highly oleophobic. The highly hydrophilic composition may comprise nanoparticles held to the cover by one or more types of silanes and preferably cross-linked to increase strength and prevent hydrolysis during use. The highly hydrophilic composition may further comprise a hydrophilic surface modifying agent (e.g., a polyethylene glycol compound) to maximize hydrophilicity.
An exemplary a method of performing a laparoscopic procedure comprises: (1) positioning a nanoscopically and/or microscopically rough surface on at least a viewing and illumination portion of a surgical viewing instrument; (2) positioning the laparoscope at a surgical site; and (3) utilizing the laparoscope to illuminate and view the surgical site, (4) the nanoscopically and/or microscopically rough surface reducing or preventing adhesion of substances that obstruct vision at the surgical site. According to one embodiment, positioning the nanoscopically and/or microscopically rough surface comprises placing a sheath (e.g., an elongate tubular member) carrying the nanoscopically and/or microscopically rough surface over at least a portion of the laparoscope. According to another embodiment, positioning the nanoscopically and/or microscopically rough surface comprises placing a transparent film (e.g., an adhesive strip) carrying the nanoscopically and/or microscopically rough surface over at least a portion of the laparoscope.
An exemplary method for manufacturing a cover for use with a surgical viewing instrument for providing clearer and less obstructed vision at a surgical site comprises: (1) providing a polymeric member configured for placement over at least a portion of a surgical viewing instrument, at least a portion of the cover being transparent to light; and (2) forming a nanoscopically and/or microscopically rough surface on at least a portion of the polymeric member, wherein the nanoscopically and/or microscopically rough surface reduces or prevents adhesion of substances that obstruct vision at a surgical site.
According to one embodiment, forming the nanoscopically and/or microscopically rough surface on the polymeric member comprises: (1) reacting an organic binder with functional groups on the polymer surface to bond organic binder molecules to the polymer surface; (2) reacting nanoparticles with the organic binder molecules; (3) reacting a cross-linking agent with the nanoparticles to form cross-linked nanoparticles; and (4) applying a surface modifying agent to the cross-linked nanoparticles. The polymer surface and intermediate modified polymer surfaces can be activated using plasma or chemical activation.
According to another embodiment, forming the nanoscopically and/or microscopically rough surface on the polymeric member comprises: (1) forming a nanoscopically and/or microscopically roughened surface on at least one surface of a mold configured for molding a polymeric member; and (2) molding the polymeric member in the mold, wherein, in the molding, the nanoscopically and/or microscopically rough surface is imprinted on the polymeric member.
In addition to the foregoing described covers for surgical viewing instruments, the nanoscopically and/or microscopically rough surface may be formed on a number of articles including, but not limited to, ski goggles, swimming goggles, glasses, windows, vehicle windshields, motorcycle fairings, camera lenses, waterproof enclosures for cameras or other viewing equipment, smartphone surfaces, tablet computer surfaces, and the like. The nanoscopically and/or microscopically rough surfaces described herein can protect a surface from moisture, water, oils, solutions, liquids, ice or other materials.
These and other benefits, advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
In order that the manner in which the above recited and other benefits, advantages and features of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. The following drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope:
Disclosed herein are polymeric articles that include a nanoscopically and/or microscopically rough surface formed on at least a portion of the article. Methods of using and making such articles are also disclosed. In one embodiment, covers for use with a surgical viewing instrument that include the nanoscopically and/or microscopically rough surface are disclosed. A variety of surgical viewing instruments such as, but not limited to, laparoscope, endoscopes, capsule endoscopes, pill cameras, and surgical microscopes are routinely used for visualizing and/or illuminating a medical procedure site. However, during surgical operations, bodily fluids, blood, condensation, and the like can adhere to the observation window of the surgical viewing instrument(s) and distort, obscure and degrade visibility of the surgical site. For example, the window can fog up due to the temperature differential between the surgical viewing instrument and the warm, humid environment in and around the body. In addition, smoke, blood, and tissue debris from ablation, cutting or cautery can adhere to the window. Spraying and smudging by blood and tissue debris can also obscure vision. The nanoscopically and/or microscopically rough surface is configured to shed and/or incorporate into a thin, substantially uniform film such droplets, fogs, and debris for providing clearer and less obstructed vision at a surgical, diagnostic or procedure site.
As used herein, the term “surgical viewing instrument” shall include all instruments that are used for viewing and/or illuminating a surgical procedure site. Typical surgical viewing instruments include, but are not limited to, laparoscope, endoscopes, capsule endoscopes, pill cameras, and surgical microscopes. In some embodiments, laproscopes and endoscopes are referred to specifically. As used herein, the terms “laparoscope” and “endoscope” shall have their ordinary meaning In addition, the term “endoscope” shall broadly mean any “boroscope” unless otherwise limited. Examples of endoscopes include, but are not limited to, flexible and rigid arthroscopes, bronchoscopes, colonoscopes, cystoscopes, enteroscopes, esophagogastroduodenoscopes, hysteroscopes, laparoscopes, laryngoscopes, mediastinoscopes, sigmoidoscopes, or thoracoscopes. The covers described herein may be adapted for fit essentially any laproscope. For example, some laproscopes use a lens that is angled (e.g., 30°, 45°, etc.) relative to the elongate stem of the laproscope. Likewise, some laproscopes use a lens that is articulated and variably anglable relative to the elongate stem of the laproscope. The cover described herein may be adapted to such devices. For the sake of brevity, the term “laparoscope” is often used; however, the disclosure will apply to endoscopes and boroscopes generally unless otherwise limited.
As used herein, the term “nanoscopically and/or microscopically” refers to the fact that the surface(s) described herein may be nanoscopically or microscopically rough (i.e., the surface may include either nanoscopic or microscopic surface features) or nanoscopically and microscopically (i.e., the surface may include both nanoscopic and microscopic surface features).
The surgical viewing instrument covers described herein are especially useful in maintaining clearer and less obstructed vision in combination with a telescopic rod lens system comprised of a camera and light source. The covers have anti-adhesion properties in order to prevent or reduce adhesion of bodily fluids, blood, condensation, smoke, tissue debris and the like and/or prevent fogging and smudging. Maintaining a clearer and less obstructed vision reduces or eliminates the need to physically clean the instrument during a procedure, which can reduce the time and effort required to complete the procedure.
According to one embodiment, the inventive covers include a sheath configured for placement over at least a portion of a surgical viewing instrument and a nanoscopically and/or microscopically rough surface formed on or applied to at least a portion of the sheath. At least a portion of the sheath is advantageously transparent to light so as to act as a window through which light can pass. The nanoscopically and/or microscopically rough surface (e.g., a highly hydrophobic coating as described more fully herein) reduces or prevents adhesion of substances that obstruct vision at a surgical site, such as bodily fluids, blood, condensation, smoke, tissue debris and the like and/or prevents fogging and smudging.
In a first step 302, the polymer surface is activated to create or expose functional groups with which binder molecules can react. Activation can be achieved using any polymer surface activation method known in the art. One example of polymer surface activation is plasma (or corona) activation using radiant energy. Another example of polymer surface activation is chemical activation, such as by using a solvent, acid or base.
In subsequent step 304, an organic binder is attached to the activated polymer surface. This may be performed by chemically reacting organic binder molecules with the functional groups on the polymer surface. The organic binder molecules advantageously include reactive groups that are able to react with functional groups on the polymer surface, such as by a condensation or substitution reaction. According to one embodiment, and by way of example only, the functional groups on the polymer surface may include hydroxyl groups and the reactive groups of the organic binder molecules are amine groups capable of displacing the hydroxyl groups from the polymer surface to form an amine bond with carbon atoms on the polymer surface. If water is formed as a byproduct, the intermediate product may be dried prior to performing the next step.
In subsequent step 306, nanoparticles and/or microparticles are applied to and reacted with bonding groups of the organic binder molecules. The nanoparticles and/or microparticles provide nanoscale roughness to the nanoscopically and/or microscopically rough surface to, for example, increase the bond angle of water to the coating surface beyond whatever bond angle can be achieved by the hydrophobicity of a highly hydrophobic coating by itself. According to one embodiment, the organic binder molecules (e.g., amino silane molecules) are quick activated (e.g., heated) using plasma activation. In the case of fumed silica or titanium dioxide particles, such particles can be sonicated in ethanol and pH stabilized (e.g., using an acid, such as acetic acid) to deagglomerate the nanoparticles to provide a colloidal mixture prior to application to the organic binder treated polymer surface. If water is formed as a byproduct, the intermediate product may be dried prior to performing the next step.
In subsequent step 308, a cross-linking material is applied to the nanoparticles to increase strength and prevent hydrolysis of the nanoparticles from the binding agent during use. The nanoparticles can be quick activated using plasma activation. According to one embodiment, steps 306 and 308 may be combined in a single reaction vessel although two-step application and cross-linking of the nanoparticles is currently preferred.
In subsequent step 310, the cross-linked nanoparticle surface of the coating may be quick activated using plasma activation and then functionalized using one or more desired functionalizing agents. According to one embodiment, the functionalizing agent may be a hydrophobic material, such as a fluoroalkyl or silane material, which yields a highly hydrophobic coating. Adding a hydrophobic functionalizing agent serves to maximize hydrophobicity of the highly hydrophobic coating. According to another embodiment, if oleophobicity is desired, at least a portion of the cross-linked nanoparticle surface may be treated with an oleophobic functionalizing agent, such as a fluoroalkyl or another highly polar functionalizing agent. Some oleophobic materials (e.g., fluoroalkyls) may be both hydrophobic and oleophobic. According to another embodiment, a portion of the cross-linked nanoparticle surface may be treated with a hydrophilic functionalizing agent, such as polyethylene glycol (PEG) and the like. Providing hydrophobic, oleophobic, and/or hydrophilic agents yields nanoscopically and/or microscopically rough surface having desired properties for preventing adhesion of vision obscuring substances to the cover.
In general, a method for forming a nanoscopically and/or microscopically rough surface with superhydrophobic, superoleophobic, or superhydrophilic surface or combination therein involves activating a substrate to allow for the chemical bonding of an adhesion intermediate, whereby a deposition of nanoparticles and/or microparticles can be utilized to construct a roughened surface. The roughened surface can be cross-linked to ensure greater mechanical durability and may subsequently be coated with a secondary material to improve hydrophobicity, oleophobicity, and/or hydrophilicity or a combination therein.
An exemplary method for forming a superhydrophobic, superoleophobic, and/or superhydrophilic surface or combination therein comprises the steps of: (1) activating a substrate to improve chemical bonding; (2) depositing an adhesion promoter; (3) depositing nanoparticles to said surface to create a nanoscopically and/or microscopically rough surface; and (4) depositing a hydrophobic, oleophobic, and/or hydrophilic material to improve hydrophilicity, oleophobicity, or hydrophobicity or combination thereof.
According to one embodiment, a superhydrophobic surface is provided wherein the water contact angle is greater than or equal to 150 degrees and/or wherein the sliding contact angle is less than or equal to 10 degrees. In another embodiment, a superhydrophilic surface is provided wherein the water contact angle is less than or equal to 10 degrees.
According to another embodiment, a superoleophobic surface is provided. According to one embodiment, a superoleophobic surface can be defined as follows: (1) A surface with nanoscopic and or microscopic roughness; (2) a surface with a static nonpolar solution contact angle greater than or equal to 150°; and (3) surface with a hysteresis angle/sliding angle less than or equal to 10°.
According to another embodiment, a superhydrophillic surface is provided. A superhydrophillic surface can be defined as follows: (1) A surface with nanoscopic and or microscopic roughness with a static water or polar solution contact angle less than or equal to 0°.
With regard to activation of a substrate, the activation process can be performed using an oxygen plasma, a corona discharge, or using chemical means, such as a solvent, oxidizer, acid, or base.
According to one embodiment, the substrate may be comprised of an organic material. Examples include thermoset polymers, thermoplastic polymers, epoxies, furans, polyimides, melamines, polyesters, and urethanes. Examples of thermoplastic polymers include, but are not limited to, acrylonitrile butadiene styrene (ABS), celluloid, cellulose acetate, ethylene-vinyl acetate (EVA), poly(methyl methacrylate) (PMMA), polyacrylonitrile (PAN), polyamide (Nylon), polycarbonate (PC), polyether ether ketone (PEEK), polyethylene (PE), poly(ethylene terephthalate) (PET), polypropylene (PP), polystyrene (PS), polysulfone, polyvinyl chloride (PVC), styrene-acrylonitrile, polydimethylsiloxane, and combinations thereof.
According to another embodiment, the substrate may be comprised of an inorganic material. Examples include, but are not limited to, glass, silica, quartz, talc, mica, clay, aluminum, iron, steel, and combinations thereof.
According to one embodiment, the adhesion promoter can be a silane comprised of an inorganic and organic functionality with one (R3—Si—OR), two (R2—Si—(OR)2), or three (R2—Si—(OR)3) alkoxy groups. Examples of functional groups of the adhesion promoter groups include ethyl, propyl, or butyl alkoxy group. A larger end group decreases the rate of hydrolysis and formation of silanols and moreover sterically hinders alcoholysis with substrate hydroxyl groups. Advantageously, the organic functional group of the adhesion promoter is tailored to react with the specified substrate. According to one embodiment, the adhesion promoter forms a 0.1-5% solution in water adjusted to 4.5-5.5 pH with acetic acid. In another embodiment, the adhesion promoter forms a 0.1-5% solution in an aqueous mixture of 95% methanol, ethanol, or isopropanol with 5% water adjusted to 4.5-5.5 pH with acetic acid. In yet another embodiment, the adhesion promoter can be amino functionalized and form a 0.1-5% solution in water or a 0.1-5% solution in an aqueous mixture of 95% methanol, ethanol, or isopropanol with 5% water. According to another embodiment, the adhesion promoter can be deposited using a dilute solvent such as, but not limited to, methyl ethyl ketone (MEK), acetone, and/or 2-butanol, in order to facilitate in the development of an interpenetrating network between the substrate and the adhesion promoter. According to one embodiment, the adhesion promoter can be deposited under 10-30 PSI of pressure to facilitate in the development of an interpenetrating network between the substrate and the adhesion promoter. Moreover, the adhesion promoter can be deposited under an elevated temperature of 50-80° C. to facilitate in the development of an interpenetrating network between the substrate and the adhesion promoter. The adhesion promoter can be cured for 20-60 minutes at 50-110° C. or 24 hours at room temperature.
According to one embodiment, the nanoparticles can have a diameter that ranges from 10 nm and 1 micron, preferably from 10 nm to 200 nm to achieve a transparent coating. Examples of nanoparticle materials include, but are not limited to, clays, talc, mica, silica, alumina, wollastonite, titanium dioxide, and combinations thereof.
According to one embodiment, the cross linker can be classified as a dipodal silane. In one embodiment, the cross-linker can be added to the substrate following deposition of nanoparticles. In an alternative embodiment, the cross linker can be combined at a 1:5 to 1:10 ratio with the nanoparticle deposition. Examples of cross linkers include, but are not limited to, bis(triethoxysilyl)ethane, bis(triethoxysilyl)octane, bis(trimethoxysilylethyl)benzene, bis[(3-methyldimethoxysilyl)propyl]-polypropylene oxide.
In an alternative method, the nanoscopically and/or microscopically rough surface may be formed on a polymeric surface using a deformation process. For example, a thermoplastic substrate is heated and strained but not beyond yield. The plastic is dipped in an appropriate adhesion promoter with an organofunctional group and three alkoxy groups. Tetraethylorthosilicate may be included to produce a sizable glass layer. When allowed to relax the glass layer should induce strain wrinkling and nanoscopic wrinkles
In another embodiment, the nanoscopically and/or microscopically rough surface may be formed on a polymeric surface using a molding process. For example, the aforementioned nanoscopically and/or microscopically rough surfaces may be formed on one or more surfaces of a mold, which can be subsequently be used to mold a plastic (e.g., by injection molding or thermosetting) to form a nanoscopically and/or microscopically rough surface on the polymer surface. Such a surface would not necessarily include nanoparticles and the like, but would instead include the impression of the nanoparticles. In another embodiment, a nanopore aluminum oxide template is produced and used to hot emboss a polymer substrate to achieve a nanoscopically roughened surface. Such surfaces may be highly hydrophobic, highly oleophobic, and/or highly hydrophilic depending in the type of polymer chose to form the polymer surface.
A nano/microscopically rough surface created by the electrospinning of polymeric fibers or droplets to form a surface with nano/microsized features.
Alternatively, the nanoscopically and/or microscopically rough surface may be formed on a polymeric surface by one or more of wet etching of the substrate with appropriate chemicals to form a surface with nano/microsized features, dry etching the substrate with plasmas, reactive ions, or corona discharge to form a surface with nano/microsized features, by a layer-by-layer deposition of varying polyanions and polycations to form a surface with nano/microsized features, by chemical vapor deposition of reactants to form a surface with nano/microsized features, by a sol-gel deposition of a polycondensed network to form a surface with nano/microsized features, or by phase separation of a polymer to form a surface with nano/microsized features.
The elongate tubular member of the laparoscope cover 500 can be blow molded from an appropriate polymer (e.g., PETG) that can accept a nanoscopically and/or microscopically rough surface as described herein or that may hereafter be developed or is already known in the art. The hub member can be directly molded over, or separately molded and then attached to, the proximal end of the elongate tubular member.
The exemplary laparoscope cover 500 can be held in place over a laparoscope during use by friction lock near the proximal end of the laparoscope handle. The fiber optics of the laparoscope will be partially or entirely disposed into the sheath. The sheath can be closed at the distal end to provide a sterile barrier to at least the distal end if not the entire laparoscope. In the case where the laparoscope is prone to getting very hot, the sheath can protect against fire (e.g., a patient surgical drape made of paper) and reduce the spread of heat inside the tip. This keeps the heat inside the sheath, which can reduce the temperature gradient between the laparoscope and the patient's body in order to reduce condensation on the sheath. The sheath can also act as a heat sink to distribute and dissipate heat to decrease the tendency of heat to be focused at the tip where light is emitted.
The suface coating on the laparoscope cover 500 provides nanoscale roughness, which maximizes the contact angle of a water droplet on the treated polymer surface. The “contact angle” refers to the angle of the tangent of the water droplet to the surface. A perfect sphere on a hard surface (e.g., marble on a table) would have a contact angle approaching or equaling 180°.
Through hydrophobic chemistry alone, it is estimated that the maximum possible contact angle of a water droplet is about 120°. However, nanoscale roughness provided by the nanoparticles reduces the contact surface area between the water droplet and the polymer surface and traps air. This creates a liquid-air interface having much lower friction and bonding attraction compared to a liquid-solid interface, thereby increasing the ability of the natural surface tension of the water droplet to form a more spherical droplet and adhere less to the polymer surface. According to one embodiment, the highly hydrophobic composition or coating is formulated so as to cause water or protein-based droplets to have a surface angle relative to the polymer surface of at least about 135°, preferably at least about 140°, and more preferably at least about 150°. In the case of blood, the contact angle would be expected to be somewhat lower because blood has lower surface tension than water.
Similar logic holds for an oleophobic surface. Through oleophobic chemistry alone, it is estimated that the maximum possible contact angle of an oil droplet or a similar non-polar substance is about 120°. However, nanoscale roughness provided by the nanoparticles coupled with oleophobic surface treatment reduces the contact surface area between the oil droplet and the polymer surface and traps air. This creates a liquid-air interface having much lower friction and bonding attraction compared to a liquid-solid interface, thereby increasing the ability of the natural surface tension of the oil droplet to form a more spherical droplet and adhere less to the polymer surface. According to one embodiment, the highly oleophobic composition or coating is formulated so as to cause oil or non-polar droplets to have a surface angle relative to the polymer surface of at least about 135°, preferably at least about 140°, and more preferably at least about 150°. However, in the case of oil droplets or droplets of other non-polar liquids, the contact angle would be expected to be somewhat lower that with water because oils and other non-polar liquids have lower surface tension than water.
In the case of a highly hydrophilic surface, the nanoscale roughness provided by the nanoparticles coupled with hydrophilic surface treatment is expected to “wick” water into the surface such that water and other aqueous liquids will form a thin, substantially uniform layer of water that covers the surface. Such a thin, substantially uniform layer of water can, for example, prevent fogging by water condensation on the surface.
The highly hydrophobic composition is also formulated so as to reduce the sliding or hysteresis angle of a droplet of water on a polymer surface as much as possible. The “sliding angle” is the angle beyond level at which a droplet of water or blood runs off the highly hydrophobic surface.
According to one embodiment, a composition may contain discrete regions of superhydrophobic and superhydrophilic materials. Superhydrophilic materials can be made in the same way as superhydrophobic materials by placing a superhydrophilic substrate on the outer surface of the composition.
Providing a laparoscope cover with a highly hydrophobic coating that provides a high contact angle and/or low hysteresis angle of a droplet of water or blood on the surface maximizes visibility and light transmittance. These features increase light transmittance by preventing or reducing formation of a uniform fog layer over the laparoscope cover. According to one embodiment, the polymer material used to make the sheath of the laparoscope cover and the highly hypdrophobic coating are sufficiently transparent that light transmittance is not reduced by more than about 20%, and preferably less than 20%. The size of the nanoparticles also affects light transmittance. Nanoparticles larger than about 200 nm can cause light scattering, which can blur the view. Nanoparticles smaller than about 200 nm typically do not scatter light, which increases light transmittance and sharpness of the image produced by the laparoscope. According to one embodiment, the laparoscope cover and highly hydrophobic composition are configured so that the laparoscope cover does not decrease light transmittance from a laparoscope by more than about 20%.
The laparoscope cover may alternatively comprise a sheath with a hydrophobic coating thereon in the form of a flexible film (i.e., “band-aid”) (not shown) that can be applied to the observation window to provide the non-stick coating.
For purposes of this disclosure, the term “laparoscope” can be considered an “endoscope” as well. Both can also be termed a borescope. Accordingly, the foregoing description relative to applying a highly hydrophobic coating to a laparoscope cover can also be applicable to an endoscope cover for use with an endoscope for providing clearer and less obstructed vision at a surgical, diagnostic or procedure site. The endoscope cover may comprise a sheath configured for placement over at least a portion of an endoscope, at least a portion of the sheath being transparent to light, and a non-stick coating on at least a portion of the sheath that reduces or prevents adhesion of substances that obstruct vision at a surgical site.
An exemplary method of performing a laparoscopic procedure includes: (1) providing a cover configured to be fitted onto a laproscope, wherein the cover includes a nanoscopically and/or microscopically rough surface that may be at least one of a highly hydrophobic, highly oleophobic, or highly hydrophilic; (2) positioning the cover including the nanoscopically and/or microscopically rough surface adjacent to at least a portion of a laparoscope, wherein the nanoscopically and/or microscopically rough surface reduces or prevents adhesion of substances that obstruct vision; (3) positioning the laparoscope at a surgical site; and (4) utilizing the laparoscope to illuminate and view the surgical site, (5) the nanoscopically and/or microscopically rough surface reducing or preventing adhesion of substances that obstruct vision at the surgical site.
It will also be appreciated that the present claimed invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. Additionally, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.
This application claims the benefit of and priority to U.S. Prov. Pat. App. Ser. No. 61/720,877 filed 31 Oct. 2012 and U.S. Prov. Pat. App. Ser. No. 61/720,896 filed 31 Oct. 2012, the entireties of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US13/67751 | 10/31/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61720877 | Oct 2012 | US | |
| 61720896 | Oct 2012 | US |
