Patent Application
20220395587
There is an important need to develop practical, efficient, “label-free” diagnostic and seamless therapeutic methods and systems to monitor the viability of cellular systems and, in some instances, induce gene regulation, for use in a variety of biomedical applications (e.g., cancer diagnostics and therapy, infectious disease monitoring and treatment, regeneration of damaged tissue, stem cell therapy, tissue engineering, use of artificial organs, treatment of disease, etc.). For example, methods and systems to detect early molecular biomarkers (miRNAs, mRNA, DNA, proteins, peptides, metabolites, etc.) of cellular systems and treat associated diseases are needed.
The Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In a first aspect of the invention, a nanoprobe system for in vivo use comprises a plasmonic-active nanoparticle and a molecular probe system. The molecular probe system comprises an oligonucleotide capable of forming a stem-loop configuration, having a first end and a second end, wherein the oligonucleotide is immobilized to the plasmonic-active nanoparticle at the first end and labeled with a Raman reporter at the second end, a placeholder strand at least partially bound to the oligonucleotide, and an attachment mechanism for attachment to a cell membrane.
In a second aspect of the invention, a method of in vivo monitoring and/or detection comprises administering a nanoprobe system to a subject, the nanoprobe system comprising a plasmonic-active nanoparticle; an oligonucleotide having a first end and a second end, wherein the oligonucleotide is immobilized to the plasmonic-active nanoparticle at the first end and labeled with a Raman reporter at the second end; a placeholder strand complimentary to and at least partially bound to the oligonucleotide; and an attachment mechanism for attachment of the nanoprobe system to a cell membrane. The placeholder strand targets a specific sequence and upon exposure of the nanoprobe system to the specific target sequence, the placeholder strand leaves the oligonucleotide in favor of the target sequence, allowing the oligonucleotide to fold into a closed stem-loop configuration whereby the Raman reporter is near or on the plasmonic-active nanoparticle surface thereby yielding a SERS signal. The SERS signal is detected with a detection device.
In a third aspect of the invention, a method of in vivo therapy comprises administering a nanoprobe system to a subject in need of a desired therapy, the nanoprobe system comprising a plasmonic-active nanoparticle; an oligonucleotide having a first end and a second end, wherein the oligonucleotide is immobilized to the plasmonic-active nanoparticle at the first end and labeled with a Raman reporter at the second end; a placeholder strand complimentary to and at least partially bound to the oligonucleotide; a component for inducing molecular regulation linked to the placeholder strand; and an attachment mechanism for attachment of the nanoprobe system to a cell membrane. The placeholder strand targets a specific sequence, and upon exposure of the nanoprobe system to the specific target sequence, the placeholder strand leaves the oligonucleotide in favor of the target sequence, allowing the oligonucleotide to fold into a closed stem-loop configuration whereby the Raman reporter is near or on the plasmonic-active nanoparticle surface thereby yielding a SERS signal. The component for inducing molecular regulation separates from the placeholder strand thereby initiating the desired therapy. The SERS signal is detected with a detection device.
The accompanying Figures are provided by way of illustration and not by way of limitation. The foregoing aspects and other features of the disclosure are explained in the following description, taken in connection with the accompanying example figures relating to one or more embodiments.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to preferred embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alteration and further modifications of the disclosure as illustrated herein, being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
Articles “a” and “an” are used herein to refer to one or to more than one (i.e. at least one) of the grammatical object of the article. By way of example, “an element” means at least one element and can include more than one element.
“About” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “slightly above” or “slightly below” the endpoint without affecting the desired result.
The use herein of the terms “including,” “comprising,” or “having,” and variations thereof, is meant to encompass the elements listed thereafter and equivalents thereof as well as additional elements. As used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations where interpreted in the alternative (“or”).
As used herein, the transitional phrase “consisting essentially of” (and grammatical variants) is to be interpreted as encompassing the recited materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. Thus, the term “consisting essentially of” as used herein should not be interpreted as equivalent to “comprising.”
Moreover, the present disclosure also contemplates that in some embodiments; any feature or combination of features set forth herein can be excluded or omitted. To illustrate, if the specification states that a complex comprises components A, B and C, it is specifically intended that any of A, B or C, or a combination thereof, can be omitted and disclaimed singularly or in any combination.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if a concentration range is stated as 1% to 50%, it is intended that values such as 2% to 40%, 10% to 30%, or 1% to 3%, etc., are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this disclosure.
As used herein, “treatment,” “therapy” and/or “therapy regimen” refer to the clinical intervention made in response to a disease, disorder or physiological condition manifested by a patient or to which a patient may be susceptible. The aim of treatment includes the alleviation or prevention of symptoms, slowing or stopping the progression or worsening of a disease, disorder, or condition and/or the remission of the disease, disorder or condition.
The term “effective amount” or “therapeutically effective amount” refers to an amount sufficient to effect beneficial or desirable biological and/or clinical results.
As used herein, the term “subject” and “patient” are used interchangeably herein and refer to both human and nonhuman animals. The term “nonhuman animals” of the disclosure includes all vertebrates, e.g., mammals and non-mammals, such as nonhuman primates, sheep, dog, cat, horse, cow, chickens, amphibians, reptiles, and the like. The methods and compositions disclosed herein can be used on a sample either in vitro (for example, on isolated cells or tissues) or in vivo in a subject (i.e. living organism, such as a patient). In some embodiments, the subject comprises a human who is undergoing a procedure using the systems and methods prescribed herein.
Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
Nanoprobe systems and methods of using them for detection, monitoring, diagnostics and/or therapeutics are described herein. In embodiments, the use of nanoprobe systems for in vivo monitoring, detection, diagnostics and/or treatment are described. When nanoprobe systems are used in vivo, consideration of how the systems will interact with, be taken into or delivered to and distributed in cells is important. In embodiments, the nanoprobe system comprises an attachment mechanism for use in attaching the nanoprobe system to a cell membrane. The attachment mechanism can attach the nanoprobe system inside the cell (intracellular) or outside the cell (extracellular). Techniques for intracellular delivery of nanoprobe systems, as well as providing surface modifications to prevent aggregation and optimize surface-enhanced Raman scattering (SERS) signal strength can be important. For example, targeting of cells may be improved by using targeting proteins/peptides on the nanoprobe surface. An exemplary peptide is the HIV-1 TAT for nuclear entry. Aggregation of nanoprobe systems can be addressed by use of pre-stabilized nanoprobes, which may be coated with poly(ethylene glycol) (PEG) ligands. With regard to plants, synthesized magnetic nanoprobe systems can be delivered into plant cells with and without cell walls using an external magnetic field. Two-dimensional (2D) Raman imaging can identify and locate nanoprobe systems within single cells using SERS. The uptake efficiency of nanoprobe systems in single cells can be monitored via SERS imaging, and uptake efficiency can be enhanced via surface modification with charged or uncharged molecular labels.
As used herein, the term nanoprobe system refers to a system comprising a plasmonic-active nanoparticle (for example, gold nanostars, metallic nanostructures, etc.) and a molecular probe system (for example, an oligonucleotide capable of forming a stem-loop configuration, etc,).
A nanoprobe (also referred to as nanosensor) system comprises a plasmonic-active nanoparticle and a molecular probe system; said molecular probe system comprises an oligonucleotide capable of forming a stem-loop configuration, having a first end and a second end, wherein the oligonucleotide is immobilized to the plasmonic-active nanoprobe at the first end and labeled with a Raman reporter at the second end, and an unlabeled placeholder strand at least partially bound to the oligonucleotide. A nanoprobe system may also comprise a siRNA or other molecular probe systems for use in therapy.
A brief summary of basic plasmonic principles is provided in order to explain how the plasmonic-active nanoparticle is able to provide detection and monitoring capabilities. Electromagnetic enhancements are divided into two main classes: a) enhancements that occur only in the presence of a radiation field, and b) enhancements that occur even without a radiation field. The first class of enhancements is further divided into several processes. Plasma resonances on the substrate surfaces, also called surface plasmons, provide a major contribution to electromagnetic enhancement. An effective type of plasmonics-active substrate consists of nanostructured metal particles, protrusions, or rough surfaces of metallic materials. Incident light irradiating these surfaces excites conduction electrons in the metal, and induces excitation of surface plasmons leading to Raman/Luminescence enhancement. At the plasmon frequency, metal nanoparticles (or nanostructured roughness) become polarized, resulting in large field induced polarizations and thus large local fields on the surface. These local fields increase the luminescence/Raman emission intensity. As a result, the effective electromagnetic field experienced by the analyte molecule on theses surfaces is much larger than the actual applied field. In the electromagnetic models, the luminescence/Raman-active analyte molecule is not required to be in contact with the metallic surface but can be located anywhere within the range of the enhanced local field, which can polarize this molecule. There are two main sources of electromagnetic enhancement: (1) first, the laser electromagnetic field is enhanced due to the addition of a field caused by the polarization of the metal particle; (2) in addition to the enhancement of the excitation laser field, there is also another enhancement due to the molecule radiating an amplified Raman/Luminescence field, which further polarizes the metal particle, thereby acting as an antenna to further amplify the Raman/Luminescence signal. Plasmonics-active metal nanoparticles also exhibit strongly enhanced visible and near-infrared light absorption, several orders of magnitude more intense than conventional laser phototherapy agents. The use of plasmonic nanoparticles as highly enhanced photoabsorbing agents has introduced a much more selective and efficient phototherapy strategy. The tunability of the spectral properties of the metal nanoparticles and the biotargeting abilities of the plasmonic nanostructures make their use promising.
The SERS effect can enhance the efficiency of light emitted (Raman or luminescence) from molecules adsorbed at or near a metal nanostructure's Raman scatter.
The intensity of the normally weak Raman scattering process is increased by factors as large as 1013 or 1015 for compounds adsorbed onto a SERS substrate, allowing for single-molecule detection. As a result of the electromagnetic field enhancements produced near nanostructured metal surfaces, nanoparticles have found increased use as fluorescence and Raman nanoprobes.
When a nanostructured metallic surface is irradiated by an electromagnetic field (e.g., a laser beam), electrons within the conduction band begin to oscillate at a frequency equal to that of the incident light. These oscillating electrons, called “surface plasmons,” produce a secondary electric field which adds to the incident field. If these oscillating electrons are spatially confined, as is the case for isolated metallic nanospheres or roughened metallic surfaces (nanostructures), there is a characteristic frequency (the plasmon frequency) at which there is a resonant response of the collective oscillations to the incident field. This condition yields intense localized field enhancements that can interact with molecules on or near the metal surface. Secondary fields are typically most concentrated at points of high curvature on the roughened metal surface.
Nanoprobe systems are effective for diagnostic and therapeutic applications because they can attach via attachment mechanism to cell membranes both inside the cell (intracellular) and outside the cell (extracellular) for in vivo use.
In embodiments, endocytosis can be used as a technique for delivering SERS nanoprobes (NPs) into cells. For example, nanoprobes can be delivered into living cells by modulating the surface charge on the nanoparticles or functionalization with nuclear targeting peptides, such as, for example, HIV-1 protein-derived TAT peptides. Additional nuclear targeting peptides can include, without limitations a glutamate peptide coupled to the N-terminus of the Oct6 NLS, a modified mRNA transporter, and the M9 component of heterogeneous nuclear ribonucleoprotein-A1. Additionally, electroporation can be used to introduce nanoprobes into cells for intracellular sensing. Electroporation applies electrical pulses to induce transient and reversible pores in the cell membrane, which allow exogenous substances like nanoprobes to enter the cells.
Moreover, in embodiments, nanoprobes can be anchored on cell membranes for extracellular sensing by conjugating nanoparticles with various membrane anchors, including lipids, cholesterol, porphyrin, tocopherol, acyl chain, oleyl chain, or dioleylphosphatidylethanolamine.
Inverse molecular sentinel (iMS) nanoprobes, which will be described in greater detail below, can be delivered into or onto living cells in the same way as described above for nanoprobes in general. For example, iMS nanoprobes can be delivered into living cells by modulating the surface charge on the nanoparticles, functionalizing the nanoparticle with nuclear targeting peptides such as HIV-1 protein-derived TAT peptides, and electroporation.
Moreover, in embodiments, iMS nanoprobes can be functionalized with membrane anchors, such as lipid, cholesterol, porphyrin, tocopherol, acyl chain, oleyl chain, and dioleylphosphatidylethanolamine, which anchor iMS nanoprobes to the outer cell membrane for extracellular sensing. A membrane-anchor-modified iMS nanoprobe can link to the inner cell membrane for intracellular sensing. Moreover, iMS nanoprobes can be functionalized with antibodies, peptides or ligands that specifically interact with cell membrane receptors for anchoring iMS nanoprobes to the outer cell membrane for extracellular sensing as shown in
Molecular Sentinel nanoprobes and Inverse Molecular Sentinel nanoprobes will be described in greater detail. “Molecular Sentinel” (MS) nanoprobes are label-free detections system that use SERS for multiplexed detection of gene targets. MS nanoprobes are described in U.S. Pat. No. 7,951,535.
An Inverse Molecular Sentinel (iMS) works in a different way than the MS described above. The nanoprobe system described and used herein is an inverse molecular sentinel system.
In embodiments, the placeholder strand can have a linker to maintain proximity to the nanoprobe after it is released from the oligonucleotide thus enabling the placeholder to be reused.
In embodiments, nanoparticles may include, without limitation, silver nanospheres, gold nanospheres, silver and gold nanoshells, and silver and gold nanostars. Such nanoparticles can be used to yield intense SERS signals of the Raman label at different plasmon resonance wavelengths. The “stem-loop” oligonucleotide can have a Raman dye at one end (the first end) as the reporter, and a thiol group at the other end (the second end) for attaching to the nanoparticle. The “stem-loop” oligonucleotide can be designed to comprise a stem duplex region, a spacer and a placeholder binding region. The stem duplex region will allow the stem-loop structure to form after the placeholder-strand binds to the target molecule and leaves the nanoprobe system. The spacer is designed to provide sufficient distance (over 10 nm) between the Raman dye and plasmonics-active nanoparticle surface to reduce background SERS signal when the probe is open. The placeholder binding region binds to the placeholder-strand to prevent the formation of the stem-loop structure in the oligonucleotide. The placeholder-strand is complementary to the placeholder binding region of the oligonucleotide and to the target sequences.
iMS nanoprobe systems may include the use of aptamers. Aptamers are single-stranded DNA or RNA oligonucleotides that can fold into unique structures with high affinity and specificity to their target molecules. Various aptamers have been generated through the process of “systematic evolution of ligands by exponential enrichment” (SELEX) to recognize a wide range of molecules, including proteins, phospholipids, sugars, nucleic acids, as well as small molecules. iMS nanoprobe systems having aptamers (as shown in the
In additional embodiments, an iMS nanoprobe system can serve as an absorber by keeping targets with a capture probe to help remove or decrease the level of target RNA, for example, mRNA, long non-coding RNA (lncRNA) or DNA. In the situation with larger targets, (mRNA, lncRNA, DNA), the iMS nanoprobe system can be designed so that multiple iMS nanoprobe systems, each having shorter sequences, can hybridize cumulatively with the longer mRNA or DNA targets. Each nanoprobe system can have a different Raman/SERS label, thus enabling multiplex detection of multiple targets simultaneously. An additive multiplex approach produces multiple SERS signals associate with the different Raman labels. Spectral analysis of the SERS signals can provide information on the specificity and effectiveness of hybridization.
In another embodiment, different nanoprobe systems, having the same Raman label can target multiple segments within the same mRNA or lncRNA target. The presence of targets can be identified from the collective SERS signal from the same Raman/SERS label. This produces an additive effect leading to enhanced total SERS signal and inhibition efficiency. Targeting to multiple segments within the same gene can also reduce the off-target effect.
In additional embodiments, an iMS nanoprobe system can further comprise siRNA for therapeutic purposes. Small interfering RNA (siRNA) can regulate the expression of genes, by a phenomenon known as RNAi (RNA interference). The use of siRNA requires ‘carriers’, such as the nanoprobe systems described herein, that can deliver the siRNA to the site of action inside targeted cells. Nanoprobe systems with siRNA can be used for theranostic purposes. As used herein, the term “theranostic or theranostics” includes combined aspects of detecting, monitoring, and/or diagnosing a condition, illness, ailment, disorder and/or disease and treatment or therapy related thereto.
In embodiments, the nanoprobe systems described herein further comprise siRNA thereby enabling the delivery of siRNAs and antisense oligonucleotides, which induce gene regulation (e.g., gene silencing, antisense blocking) and simultaneously produce a signal indicating the gene regulation process. Antisense oligonucleotides are synthetic DNA oligomers that hybridize to target RNA and can be used to induce gene regulation.
Embodiments of the systems, methods and instrumentation described herein can deliver molecular nanoprobe systems comprising various components (e.g., siRNAs, aptamers, or other molecular probes) into cells or outside cells (extracellular matrix, tissues, bodily fluids, etc.) or on cell surface membranes. In embodiments, the nanoprobes described herein can induce molecular regulation mechanisms (e.g., specifically targeted gene silencing, antisense-based blocking, mRNA blocking, miRNA blocking, aptamer-based molecular regulation, etc.) for desired therapy and produce a corresponding sensing signal (theranostics). Such a signal is important for many purposes, such as monitoring the presence of a target and efficiency of treatment.
A brief description of siRNA is provided below.
The concept of using small interfering RNA (siRNA) also includes single-stranded antisense RNA (ss-siRNA), because single-stranded antisense siRNAs also inhibit gene expression.
An iMS nanoprobe system comprising siRNA can be used to detect target nucleotides and induce molecular regulation systems. In embodiments, the siRNA can be double strand siRNA (ds-siRNA) or single strand (ss-miRNA). Detection of nucleotides and/or induction of molecular regulations systems can be direct (i.e., take place without outside or additional stimuli) or can be brought about through an external stimulus, such as light (e.g., photocleavage) or heat. Exemplary embodiments comprising siRNA are represented by the schematic diagrams shown in
In embodiments, the nanoprobe system can comprise both siRNA and an aptamer.
Nanoparticles in the nanoprobe systems can have different shapes and configurations. For example, nanoprobes may have semi-nanoshells and nanoshells, which are partial or complete metallic coatings on a nanoparticle. For example, a semi-nanoshell can be a coating of silver on one side (nanocaps or half-shells) of a nanoparticle. Plasmon resonance of a shell can be tuned by controlling the shell thickness. The shells typically are constructed of a metallic layer over a dielectric core. Prolate and oblate spheroidal shells have been studied. The spheroidal shell has two degrees of freedom for tuning: the shell thickness and the shell aspect ratio. Additionally, the nanoparticle can have a star-shaped structure. Nanostars can be plasmonics-active and induce strong SERS signals.
Nanostars of different plasmonic properties can be synthesized using a surfactant-free seed-mediated growth method to evaluate SERS intensity.
By controlling the geometry, the nanostar plasmon can be tuned to match the excitation laser frequency. To achieve superior SNR and scattering background in tissue, both the laser wavelength working range and the nanostar plasmon will be optimized experimentally. The size of nanostars can be controlled or manipulated by adding different amounts of Au seeds during synthesis: the more seeds added, the smaller the final nanostars size.
Nanostars can exhibit superior SERS properties because of their tunable plasmon, for matching the excitation wavelength, and multiple sharp branches, each with a strongly enhanced electromagnetic field localized at its tip (i.e. “lightning rod” plasmonic effect). The largest E-field enhancement occurs at the tips of the branches of the star. Nanostars size and shape can be tuned based on end use application. That is nanostars (e.g., gold nanostars) of varying sizes and numbers of branches can be synthesized to generate the most intense SERS signal for a given label.
Many embodiments of nanoprobe systems are envisaged. Some exemplary embodiments are shown in
The nanoprobe systems described herein include a bioreceptor. The bioreceptor generally includes the oligonucleotide and the capture probe or placeholder strand of the nanoprobe system. Bioreceptors are the key to specificity for targeting disease cells or mutated genes or specific biomarkers. Bioreceptors can take many forms. However, bioreceptors can generally be classified into five different major categories. The categories include: 1) antibody/antigen, 2) enzymes, 3) nucleic acids/DNA, 4) cellular structures/cells and 5) biomimetic (aptamers, peptides, etc.).
Bioreceptors can include DNA. Biologically active gene probes (i.e., DNA) can be directly or indirectly immobilized onto a nanoparticle surface to ensure optimal contact and maximum binding. When immobilized onto gold nanoparticles, the gene probes are stabilized and, therefore, can be reused repetitively. Several methods can be used to bind DNA to different supports.
Bioreceptors can include Aptamers. Aptamers are oligonucleotide or peptide molecules that bind to a specific target molecule. Aptamers are usually created by selecting them from a large random sequence pool, but natural aptamers also exist in riboswitches. Aptamers can be combined with ribozymes to self-cleave in the presence of their target molecule.
Bioreceptors can include Antibody Probes. Antibodies are biological molecules that exhibit very specific binding capabilities for specific structures. An antibody is a complex biomolecule, made up of hundreds of individual amino acids arranged in a highly ordered sequence. For an immune response to be produced against a particular molecule, a certain molecular size and complexity are necessary: proteins with molecular weights greater than 5000 Da are generally immunogenic. The way in which an antigen and its antigen specific antibody interact may be understood as analogous to a lock and key fit, by which specific geometrical configurations of a unique key enables it to open a lock. In the same way, an antigen specific antibody “fits” its unique antigen in a highly specific manner. This unique property of antibodies is the key to their usefulness in immunosensors where only the specific analyte of interest, the antigen, fits into the antibody binding site.
Bioreceptors can include Enzyme Probes. Enzymes are often chosen as bioreceptors based on their specific binding capabilities as well as their catalytic activity. In biocatalytic recognition mechanisms, the detection is amplified by a reaction catalyzed by macromolecules called biocatalysts. With the exception of a small group of catalytic ribonucleic acid molecules, all enzymes are proteins. The catalytic activity provided by enzymes allows for lower limits of detection than would be obtained with common binding techniques. The catalytic activity of enzymes depends upon the integrity of their native protein conformation. If an enzyme is denatured, dissociated into its subunits, or broken down into its component amino acids, its catalytic activity is destroyed. Enzyme-coupled receptors can also be used to modify the recognition mechanisms.
Bioreceptors can include Protein-catalyzed capture agents (PCCs). PCCs are synthetic and modular peptide-based affinity agents that can be used as receptors.
In embodiments of the nanoprobe system, silver nanoparticles are used. The surface of the silver nanoparticle can be functionalized to enable more stable immobilizing of the bioreceptor to the nanoparticle. For example, the Ag surface can functionalized with alkylthiols, which form stable linkages. Alkylthiols readily form self-assembled monolayers (SAM) onto silver surfaces in micromolar concentrations. The terminus of the alkylthiol chain can then be directly used to bind biomolecules, or can be easily modified to do so. The length of the alkylthiol chain can keep the biomolecules away from the surface of the nanoparticle. Furthermore, to avoid direct, non-specific DNA adsorption onto the surface of the nanoparticle, alkylthiols can be used to block further access to the surface, allowing only covalent immobilization through the linker.
Moreover, the surface of the nanoparticle can also be functionalized with folic acid. Folic acid (FA) is one of the most common targeting ligands employed for nanoparticle delivery. Many cancer cells overexpress the folate receptor, while normal cells typically have little to no folate receptor expression. By functionalizing the surface of nanoparticles with FA, they can be used to specifically label FR-positive cells for detection by SERS, followed by PDT treatment. In an exemplary embodiment, the nanoprobe system can comprise a silver-embedded gold nanostar that acts as a SERS tag for Raman imaging Photosensitizer molecules can be loaded onto the SERS tag by encapsulating them in a silica shell for PDT treatment. Selective detection and treatment of folate receptor positive cells have been demonstrated when breast cancer cells were used as a folate receptor negative control.
Folate-targeted Raman tags can be synthesized by coating pMBA-labeled nanostars with silver to enhance the SERS signal and subsequently coated with silica using a modified Stöber method. The silica-coated particles can be first modified with (3-aminopropyl)triethoxysilane (APTES) to provide free amine groups on the particle surface prior to being functionalized with Folic acid (FA)-PEG-NHS.
Exemplary embodiments of molecular systems for targeting various miRNA biotargets are shown in
When nanoprobe systems comprising oligonucleotides are used in cell culture or in vivo applications, degradation by nucleases is a concern. Unmodified DNA and RNA oligonucleotides are quickly digested in vitro and in vivo by endogenous nucleases. Multiple endo- and exonucleases exist in vivo. Generally, in serum, the bulk of biologically significant nucleolytic activity occurs as 3′ exonuclease activity, while within the cell, nucleolytic activity is affected by both 5′ and 3′ exonucleases.
To limit nuclease sensitivity, different modifications to the oligonucleotide, including a phosphorothioate bond, can be used. The phosphorothioate (PS) bond substitutes a sulfur atom for non-bridging oxygen in the phosphate backbone of an oligonucleotide. Approximately 50% of the time (due to the 2 resulting stereoisomers that can form), PS modification renders the internucleotide linkage more resistant to nuclease degradation. In an exemplary embodiment of the nanoprobe system, at least 3 PS bond modifications at the 5′ and 3′ oligonucleotide ends can be included to inhibit exonuclease degradation. Including PS bonds throughout the entire oligonucleotide can help reduce attack by endonucleases as well, but may also increase toxicity.
Additional modifications to the oligonucleotide can be made. A naturally occurring post-transcriptional modification of RNA, 2′OMe is found in tRNA and other small RNAs. Oligonucleotides can be directly synthesized to contain 2′OMe. This modification prevents attack by single-stranded endonucleases, but not exonuclease digestion. Therefore, the oligos having 2′OMe modification can also have end block modifications as well. DNA oligonucleotides that include this modification are typically 5- to 10-fold less susceptible to DNases than unmodified DNA. The 2′OMe modification increases stability and binding affinity to target transcripts.
Locked nucleic acids (LNA) are conformationally restricted nucleic acid analogues, in which the ribose ring is locked into a rigid C3′-endo (or Northern-type) conformation by a simple 2′-O, 4′-C methylene bridge. LNA has many attractive properties, such as high binding affinity, excellent base mismatch discrimination capability, and decreased susceptibility to nuclease digestion.
Duplexes involving LNA (hybridized to either DNA or RNA) display a large increase in melting temperatures ranging from +3.0° C. to +9.6° C. per LNA modification, compared to corresponding unmodified reference duplexes. Furthermore, LNA oligonucleotides can be synthesized using conventional phosphoramidite chemistry, allowing automated synthesis of both fully modified LNA and chimeric oligonucleotides such as DNA/LNA and LNA/RNA. Other advantages of LNA include its close structural resemblance to native nucleic acids, which leads to very good solubility in physiological conditions and easy handling. In addition, LNA is nontoxic. All these properties are highly advantageous for a molecular tool for diagnostic applications. LNA can be used in oligonucleotide-based therapeutics.
In an exemplary embodiment, a DNA/locked nucleic acid (LNA) chimeric miR-21 iMS and p53-siRNA can be used.
Thiol linkers can also be used to improve stability of the nanoprobe system. As described above, the oligonucleotide capable of forming a stem-loop configuration (stem-loop probe) is immobilized onto a metallic nanoparticle or nanostar with a metal-thiol bond. The stem-loop probe can be functionalized with either monothiol (such as alkyl-thiol) or multi-thiol anchoring groups (such as one, two or three cyclic disulfide linkers (DTPA) resulting in 2, 4, or 6 metal-sulfur bonds) for binding to a nanoparticle. Multiple thiol groups can increase the binding affinity of oligonucleotides for the metallic surface of the nanoparticle, thus leading to higher stability of metallic nanoparticle-oligonucleotide conjugates.
Raman spectroscopy offers distinct features that are important for in vivo monitoring of cellular systems for a wide variety of applications including drug discovery, biotechnology monitoring, and regenerative medicine. Following laser irradiation of a sample, the observed Raman shifts are equivalent to the energy changes involved in molecular transitions of the scattering species and are therefore characteristic of it. These observed Raman shifts, which correspond to vibrational transitions of the scattering molecule, exhibit very narrow linewidths (one Angstrom or less). For these reasons, Raman spectroscopy has a great potential for multiplexing application. That is, many organic compounds with distinct Raman spectra may be used as dyes to label biological macromolecules and each labeled molecular species will be able to be distinguished on the basis of its unique Raman spectra. This is not the case with fluorescence, because the broad spectral characteristics of fluorescence excitation and emission spectra result in large spectral overlaps if more than 3-4 fluorescent dyes are to be detected simultaneously. Note that the fluorescence emission lines of quantum dots (1-5 nm) are much larger than the Raman peaks (<0.1 nm).
In some applications, it is desirable to keep nanoprobes inactivated (i.e., not operational) for an amount of time before they are activated on demand. The iMS nanoprobe systems described herein can be designed to be photo-activatable biosensors. The nanoprobe systems can be modified to add photocleavable linkers or photo-cages to enable photoactivation. For example, a photocleavable linker can be added within the oligonucleotide backbone.
In the absence of light irradiation, the nanoprobe system is inactive. After light irradiation, the linker is cleaved and released, which activates iMS nanoprobe system. In addition, photo-removable macromolecules (e.g. proteins) can be used to inactivate iMS through steric hindrance.
Additionally, photo-cage nucleobases can be used to inactivate iMS by preventing Watson—Crick base pairs between placeholder and target strands. Exemplary photo-removable caging groups, include 1-(ortho-nitrophenyl)ethyl (NPE) and 2-(ortho-nitrophenyl)propyl (NPP).
In embodiments wherein the nanoprobe system includes therapeutic components, the placeholder strand of the nanoprobe system can perform as an antisense oligonucleotide (iMS-ASO) and can also have a siRNA linked thereto (iMS-ASO-siRNA).
In the dual-targeting scheme using the iMS-ASO-siRNA theranostic nanoprobe, the siRNA can be linked to the capture probe (acting as an ASO) directly or through a hexaethyleneglycol spacer. This design is based on the fact that siRNAs can be released from gold nanoparticles by Dicer cleavage. Alternatively, the placeholder can be linked to the siRNA through a photocleavable linker in order to release siRNAs with exposure to UV light in the 300-350 nm spectral range.
Aptamers can also be used in nanoprobe systems for theranostic applications. For example, thrombin aptamers, which can be used as anticoagulants can be used in the nanoprobe systems described herein.
One of the challenges in using nucleic acids as therapeutics is the potential stimulation of an immune response in the subject. For example, depending on the siRNA structure, sequence, and delivery method, siRNAs could stimulate innate immunity, leading to undesired side effects in vivo.
Strategies are available to overcome this challenge. For example, low immunostimulatory vehicles can be used for siRNA delivery. For instance, the innate immune response to densely functionalized, oligonucleotide-modified gold nanoparticles is less in comparison to conventional nucleic acid transfection materials, such as lipoplex. Thus, to avoid a potential immune response, the oligonucleotide density on the iMS-based theranostic nanoprobes can be increased and optimized as a low immunostimulatory system.
In addition, non-immunostimulatory iMS oligonucleotides can be designed using various 2′-modified nucleotides, including but not limited to DNA bases, 2′-O-methyl purines, 2′-fluoropyrimidines, PS linkage modifications, and terminal inverted-dT bases at certain points, which prevent siRNA immune activation. Moreover, immune response increases with the increase in hydrophobicity of the gold nanoparticle surface. Thus, the hydrophobicity of the iMS-based theranostic nanoprobe system can be optimized with PEG linkers having different functional groups.
The nanoprobe systems can be designed to identify and modify different and specific targets for various diseases. For example, an embodiment of a nanoprobe system can be designed to treat brain diseases. As described above, a nanoprobe can be designed to detect and modify miR-21 for cancer therapy. Additionally, a nanoprobe system can be designed against miR-155, which is a key regulator and therapeutic target of many neuroinflammatory and neurodegenerative disorders including Parkinson's disease, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis (ALS), traumatic brain injury, and autism.
Additionally, a nanoprobe system can be designed against miR-208a. miR-208a is a therapeutic target found at much higher levels during cardiac tissue injury in cardiovascular disease.
In embodiments, a nanoprobe system can be designed to detect and/or capture circulating tumor DNA (ctDNA) and cell-free DNA (cfDNA), which are nucleic acid fragments that enter the bloodstream during apoptosis or necrosis of normal and diseased cells.
In use, embodiments of the nanoprobe system as described herein can be used for in vivo theranostics that can serve as a real time monitor of the theranostics process to diagnose and provide treatment.
The nanoprobe systems described herein can be used to monitor the viability, operation, and shelf-life for a wide variety of medical applications, including, but not limited to, stem and precursor cells from a wide variety of sources (e.g., embryos, gestational and adult tissues), stem Cells from reprogrammed differentiated cells, insulin-producing pancreatic islets, tissue-engineered heart muscle, functional tissues and organs, tissue-engineered skin, derived from a patient's own cells, tissue-engineered bladder, derived from a patient's own cells, small intestinal submucosa (SIS), used to help the body close hard-to-heal wounds, tissue-engineered products used to induce bone and connective tissue growth, tissue-engineered vascular grafts for heart bypass surgery and cardiovascular disease treatment, and “Made-to-order” organs from 3D molecular/organic 3D printing.
The nanoprobe systems can also be applied to other non-medical applications. Additionally, nanoprobe systems can be useful in a variety of applications based on DNA/RNA/protein detection including (but not limited to), biomedical applications, point-of-care diagnostics, food safety, environmental monitoring, industrial process sensing, quality control applications, biotechnology industrial control, quality control, global health, cancer research, heart disease diagnostics, and homeland defense.
The nanoprobe system also provide enabling technologies for molecular theranostics applications that can improve cellular systems for in situ in vivo sensing (smart tattoos, implanted sensors), regenerative medicine (stem cells) and other biomedical applications. The nanoprobe systems can be used in a variety of applications including, but not limited to, disease treatment, cancer therapy, food safety, biotechnology, global health, and homeland defense.
Raman spectroscopy and two-dimensional Raman imaging were used to identify and locate nanoprobes via their surface-enhanced Raman scattering (SERS) detection. To study the efficiency of cellular uptake, silver nanoparticles functionalized with three different positive-, negative-, and neutrally-charged Raman labels were co-incubated with cell cultures, and allowed to be taken up via normal cellular processes. The surface charge on the nanoparticles was observed to modulate their uptake efficiency during a four-hour co-incubation, demonstrating a dual function of the surface modifications as tracking labels and as modulators of cell uptake.
The results indicate that the functionalized nanoprobe construct has the potential for sensing and delivery in single living cells.
The effect of complex media, such as serum, on the operation of the iMS nanosensor was investigated. Cy5-labeled iMS nanosensors (0.05 nM) were prepared and incubated with 1 μM of synthetic target DNA in a PBS buffer solution containing different concentrations of fetal bovine serum (FBS), (1) 0%, (2) 20%, (3) 40% and (4) 80% FBS, for 1 hour. Following incubation, SERS measurements were performed using a Renishaw InVia confocal Raman microscope equipped with a 632.8-nm HeNe laser.
This example provides proof-of-principle of in vivo detection of nucleic acid targets using a SERS nanosensor implanted in the skin of a large animal model (pig).
Toxicity evaluation of gold nanostars (GNS) was performed to demonstrate that they are a biocompatible platform for in vivo applications. Most of the GNS nanoparticles were cleared from the blood circulation by macrophages in the spleen and liver when examined at one week after IV injection with a dose of 20 mg/kg. For the 6-month long-term toxicity study, mouse body weight was monitored weekly and there was no statistically significant weight difference by mixed-model ANOVA analysis between the control group and groups receiving GNS doses up to 80 mg/kg. All mice were carefully monitored and did not exhibit stress or any other abnormal behavior. Mice were sacrificed 6 months after GNS injection and plasma was harvested for blood chemistry evaluation that included metabolic function of kidney and liver. One-way ANOVA statistical analyses demonstrated no statistically significant difference between control and treated groups receiving 20 mg/kg or 80 mg/kg GNS. We also performed histopathological examination of H&E stained brain, heart, liver, kidney, spleen and lung 6 months after GNS injection. No findings indicative of GNS-related toxicity were identified in mice receiving a GNS dose up to 80 mg/kg. Test groups were comparable to the control group and no deleterious effects were noted from systemic administration of GNS.
Testing was performed to demonstrate that gold nanostars with silver nanoshells, i.e., AuNS@Ag, exhibit little toxicity and can be used for in vivo studies.
Additionally, a particle retention study was performed using gamma irradiated mouse embryonic fibroblasts. There was a significant loss of particles between 48 and 72 hrs, but thereafter, a steady state was reached. Although many particles were expelled within the first 72 hrs, data showed that cells remained alive for 2 weeks with AuNS inside and retained about 100,000 particles/cell.
The Tritech Research microINJECTOR was used to inject colloidal nanoprobes into single plant cells through Femtotips microinjection capillary tips (Eppendorf), which have opening diameters of 0.5 μm±0.2 μm. An MES-KCl buffer (100 mM KCl in 5 mM MES, pH 6.5) was used atop plant cells throughout microinjection.
A Renishaw inVia Raman microscope equipped with a 633 nm He—Ne laser, running WiRE 2.0 software, was used to acquire the Raman spectra. Cells were located under brightfield transillumination with a 10× objective. The motorized stage was then set to scan the sample in a grid pattern with 30 pm step size while acquiring a spectrum at each point. For the Cy5 labeled probes, the grating was set to 558 cm-1, and the exposure time was 1 s. The false-color Raman maps were created by integrating the signal to baseline of the 558 cm-1 Raman peak of Cy5 from 533 to 583 cm-1 in the WiRE 2.0 software. For the Cy5.5 labeled probes, the grating was set to 1468 cm-1, and the exposure time was 1 s. The false-color Raman maps were created by integrating the signal to baseline of the 1468 cm-1 Raman peak of Cy5.5 from 1443 to 1493 cm-1 in the WiRE 2.0 software. The color scale between samples was kept the same.
Particle-based nanoprobe injection and detection within single plant cells was first accomplished using onion epidermal cells. The iMS probe specific to microRNA21, which was labeled with the Cy5 dye, was used. The iMS-OFF (probe open) and iMS-ON SERS nanoprobes (probe closed) were injected into single onion cells and Raman mapping was performed.
Nanoprobe injection and detection was then demonstrated within single Vicia Faba pigment cells using the microRNA21 iMS SERS nanoprobe. The iMS-ON SERS nanoprobes (probe closed) were injected into pigment cells.
Various diagnostics systems are possible, depending on the degree of miniaturization. For example, detection of a target can use a portable Raman diagnostic system having an excitation light source and an optical detector.
An exemplary embodiment of a DNA/LNA chimeric iMS was designed to allow for a longer lifetime of the nanoprobe system within cells.
Due to narrow Raman bandwidths, SERS nanoprobe systems have multiplexing capability. Three iMS nanoprobes differently labeled with Cy5, Cy5.5, and TYE665 were tested for the detection of two miRNA biomarkers, namely miR-21 and miR-194, for GI cancer, as well as, a control miRNA, miR-39.
The SERS spectra of the three nanoprobes exhibit multiple unique Raman peaks. The SERS sensing modality provides specific spectral “fingerprints” with very sharp peaks allowing sensing multiple targets simultaneously in a single assay platform. The SERS measurements were performed immediately following the incubation of samples without any washing steps to simplify and accelerate the assay procedure.
Multiplex detection was also demonstrated by mixing nanoprobes labeled with different dyes, including TYE563, Rhodamine Red, TAMRA, and Cy3. The dyes absorb light around 633 nm, which is required for resonance Raman and strong SERS signal while using a 633-nm laser as the excitation light source. Their distinctly different SERS peaks allow for their simultaneous detection.
We can use Raman spectroscopy as a modality for multiplex in vivo monitoring of cellular systems as well as in vitro detection in ultra-high throughput microarray systems. Using different tags for each reaction, it is possible to monitor several reactions simultaneously (label-multiplexing). Fluorescence has been often used as a detection method in microarrays. However, because fluorescence spectra have relatively broad band features, spectral overlap is a limitation for the use of a large number of fluorescence labels simultaneously. Due to narrow absorption bands and large spectral range, Raman provides much greater capabilities for multiplexing than fluorescence. Thus, Raman spectroscopy can be used for detection in ultra-high throughput microarray systems. The SERS technique enables the use of many different probe molecules, allowing the narrow band spectral characteristics of Raman-based probes to be used for sensitive, specific analysis of microarrays.
The resulting hyperspectral image may be presented as a 3-D data cube consisting of two spatial dimensions (x, y) defining the image area of interest and the spectral dimension (2) used to identify chemically the material at each pixel in the image.
Hyperspectral Imaging Instrumentation
The HSI system uses a rapid wavelength-scanning solid-state device, a non-collinear TeO2 AOTF, which operates as a tunable optical bandpass filter. An AOTF offers the advantage of having no moving parts and high transmission efficiency (as high as 98% at selected wavelengths) that translates into high sensitivity, thus allowing fast data acquisitions. Since AOTFs with high spatial resolution and large optical apertures are commercially available, they can be applied for spectral imaging applications. A confocal SERI system that combines a two-dimensional ICCD, APD detector and an AOTF device for hyperspectral Raman imaging applications is used.
Tunable filters, such as AOTFs and liquid crystal tunable filters (LCTFs), allow the investigator to rapidly record images at various wavelengths. An AOTF is a compact, electronically controlled bandpass filter which operate over a wide wavelength range from the ultraviolet (UV) to the far infrared (IR). The operation of an AOTF is based on the interaction of light (incident light) with an acoustic wave in a birefringent crystal. The device consists of a piezoelectric transducer bonded to one side of the crystal. The transducer emits vibrations (acoustic waves) when a radio frequency (RF) is applied to it. When an acoustic wave is generated in the crystal, a periodic modulation of the index of refraction of the crystal is established via the elasto-optic effect. This then creates a grating by alternately compressing and relaxing the lattice. Unlike a classical diffraction grating, AOTF only diffract one specific wavelength of light and as a result act as a tunable filter.
The wavelength of the diffracted beam is varied by changing the RF signal applied to the crystal, thereby adjusting the grating spacing. The Bragg grating diffracts only light that enters the crystal within an angle normal to the face of the crystal. This range is called the acceptance angle of the AOTF while the percentage of light diffracted is the diffraction efficiency of the device. The latter parameter greatly depends on the incidence angle, the wavelength selected and the power of the RF signal. Unlike commercial spectrometers where the bandwidth is fixed using interference filters incorporated into filter wheels, AOTF and LCTFs can rapidly vary (typically in less than 50 μs) the bandwidth by using closely spaced rf signals simultaneously. AOTFs can either be collinear (the incident and the diffracted light and the acoustic wave travel in the same direction) or non-collinear (the incident and the diffracted light beams travel in different directions from the acoustic wave. A non-collinear AOTF separates the first-order beam from the undiffracted beam (zero-order beam). The undiffracted light exits the crystal at the same angle as the incident light while the diffracted beam exits the AOTF at a small angle (˜6°) with respect to the incident light. The principle of operation of a non-collinear AOTF is schematically illustrated in
Instrumentation
A confocal hyperspectral Raman imaging system was used. The system consists of a Nikon Diaphot 300 Inverted microscope (Nikon, Melville, N.Y.) coupled with a 15 mW HeNe Laser (Melles Griot, 05-LHR-171) operating at 632.8 nm as the SERS excitation source. The light from the laser was passed through a set of diverging and collimating lenses (L1), an iris, and then diverted into a microscope objective (60×, 0.85 NA) using a dichroic filter (Omega Optical, 630DRLP,) and focused on a sample mounted onto the X-Y-Z translation stage. SERS signals were collected by the same objective, transmitted through the dichroic mirror, and then through a holographic notch filter (HNF) (Kaiser Optical System, 633 nm) into the AOTF device. The AOTF (Brimrose, TEAFS-0.6-0.9-UH) projected the diffracted (first-order) light at an angle different from the undiffracted (zero-order) light. The AOTF has a spectral operating range from 600-900 nm which corresponds to the relative wavenumber range (from 0 to 4691.7 cm−1 with respect to a 632.8 nm excitation and a spectral resolution of 7.5 cm−1 at 633 nm. The first order beam exiting the AOTF was passed through a beamsplitter (BS) (70/30 ratio), then through a second Iris and imaged onto a thermoelectrically cooled intensified charged-coupled device (ICCD) containing a front-illuminated chip with 512×512 two-dimensional array of 19×19 um2 (PI-Max:512 GEN II, Roper Scientific, Trenton N.J.). The ICCD was computer controlled with WinView software. The reflected beam (30%) was focused down onto the active area of an avalanche photodiode (APD) (SPCM-AQR-14, Perkin Elmer). An APD is an ideal detector for several reasons: small size, high quantum efficiency (QE) and large amplification capabilities. The APD used has a QE of ˜70% and very low dark count (<100 c/s) thus reducing the possible noise arising from the use of amplifiers. A TTL pulse of 2.5 volts is sent to a universal counter where the pulses are counted for a specified acquisition time. The APD detector is controlled by an integrated LabVIEW program developed in house. The AOTF based HSERI system is also integrated with incandescent tungsten light for bright field imaging and a mercury lamp for fluorescence imaging. In addition the SERS excitation source and the optics can be easily changed to suite any other application requiring an alternative excitation. SERS spectra and images were acquired after focusing the laser beam to an area of interest on sample or cells adhered to the glass chamber slides. The images were acquired upon excitation with 15-mW laser power and an accumulation time of 6 s (0.6 s/frame). The SERS spectra were recorded with accumulation times of 25-50 s.
For in-vivo sensing in this example, gold nanostars (AuNS) were used in the nanoprobe system. To examine the functionality of iMS nanoprobe system with AuNS, four different probes were tested with their corresponding synthetic targets. Probe-1 contained both an internal poly(adenine) spacer and a 5′-end spacer with 5 adenine bases between the hairpin probe and the AuNS surface. Probe-2 and probe-3 only contained the 5′-end spacer. Probe-4 contained neither the internal spacer nor the 5′-end spacer. The results showed that all probes can be turned ON in the presence of their specific targets. However, probe-1, with the internal poly(adenine) spacer had higher background signal than the other 3 probes when the probes were OFF.
Surfactant-free gold nanostars (AuNS) having multiple sharp branches and a plasmon tunable in the near-infrared ‘tissue optical window’ can be used in biomedical applications. The multiple sharp tips create a “lightning rod” effect that further enhances the local surface plasmon. The combined effect from the two properties brings forth high SERS intensity and enhanced two-photon photoluminescence (TPL). The AuNS have a two-photon action cross section (TPACS) up to 106-107 Goeppert-Mayer units (GM), which is higher than that of quantum dots (QDs; 104-105 GM) and organic fluorophores (102-103 GM). The AuNS can be used to study particle uptake mechanism in vitro and real-time particle tracking in vivo. In addition, high extinction coefficient (109-1010 M−1 cm−1) in the NIR region allows AuNS to be used as an exogenous contrast for in vivo photoacoustic mapping. The TPL method allows the use of NIR light for deep tissue excitation into the “optical window” of tissue.
AuNS were used to track adipose-derived stem cells (ASCs). To test the labeling efficiency of AuNS, undifferentiated ASCs were incubated for 24 hours with 0.14 nM of either Qtracker or AuNS that were functionalized with PEG and the HIV-1 protein-derived TAT peptide to promote uptake. Undifferentiated adipose-derived stem cells were stained with Hoechst33342 after a 24-hour incubation with 0.14-nM gold nanostars, and imaged with multiphoton microscopy. Gold nanostars localized to the cytoplasm of ASCs. Furthermore, cells were fixed on days 1, 2, or 4 after incubation with particles or QTracker, and imaged using two-photon photoluminescence (TPL) microscopy (
The effects of AuNS on cell phenotype, proliferation, and viability was assessed with flow cytometry, trypan blue, and MTT assays (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) respectively. Over 4 days, AuNS exhibited stronger TPL than Qtracker and did not affect cell phenotype, viability, or proliferation.
To evaluate whether AuNS-ASCs maintain the capacity for tri-lineage differentiation, AuNS-ASCs were differentiated for 21 days. Qtracker-labeled ASCs were differentiated to compare the TPL properties of both optical labels. After 21 days, cells were stained to validate their differentiated phenotype. Multiphoton mages were captured throughout differentiation. Imaging began at 7 days for adipogenesis (
AuNS-labeled cells exhibited strong TPL throughout differentiation, with only slight decay in signal over time. The decrease in signal intensity in these AuNS-labeled cells did not preclude the use of MPM. In comparison, Qtracker-labeled cells exhibited such rapid signal decay that by the 21st day, cells were not easily visualized. Analysis of AuNS and Qtracker-labeled cells using a two-way ANOVA demonstrated significantly greater TPL (p<0.001) for AuNS throughout tri-lineage differentiation. Lastly, the cytoplasmic localization of the AuNS remained undisrupted in all three lineages as demonstrated with Hoechst33342 staining. These studies show that AuNS effectively label ASCs without altering cell phenotype and exhibited stronger TPL than Qtracker throughout differentiation.
Cell-penetrating peptides can be used to overcome the lipophilic barrier of cellular membranes and deliver nanoprobe systems inside a cell for intracellular sensing. The TAT peptide (GRKKRRQRRRPQ), which is derived from the transactivator of transcription (TAT) of human immunodeficiency virus, can be used as a cell-penetrating peptide.
TAT peptide functionalized iMS nanoprobes can be used to improve cellular uptake and intracellular targeting.
The nanoprobes can be monitored using various detection systems, including, for example: (1) a portable Raman diagnostic system having excitation light source and an optical detector, (2) a pocket-sized Raman diagnostics system with fiber optics excitation and detection; or (3) a handheld battery-operated Raman reader system can be operated remotely by an iPhone or similar device.
One skilled in the art will readily appreciate that the present disclosure is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The disclosure described herein as representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the present disclosure. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the present disclosure as defined by the scope of the claims.
No admission is made that any reference, including any non-patent or patent document cited in this specification, constitutes prior art. In particular, it will be understood that, unless otherwise stated, reference to any document herein does not constitute an admission that any of these documents forms part of the common general knowledge in the art in the United States or in any other country. Any discussion of the references states what their authors assert, and the applicant reserves the right to challenge the accuracy and pertinence of any of the documents cited herein. All references cited herein are fully incorporated by reference, unless explicitly indicated otherwise. The present disclosure shall control in the event there are any disparities between any definitions and/or description found in the cited references.
This application is a U.S. National Stage Application of International Patent Application No. PCT/US20/60644, filed on Nov. 16, 2020, which claims priority to U.S. Provisional Patent Application No. 62/935,883, filed on Nov. 15, 2019, which are both incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US20/60644 | 11/16/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62935883 | Nov 2019 | US |
