Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely util... more Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely utilized to fabricate scaffolds serving as an analog of native extracellular matrix (ECM).The development of blended collagen and GAG scaffolds may potentially be used in many soft tissue ...
The development of blended collagen and glycosaminoglycan (GAG) scaffolds can potentially be used... more The development of blended collagen and glycosaminoglycan (GAG) scaffolds can potentially be used in many soft tissue engineering applications since the scaffolds mimic the structure and biological function of native extracellular matrix (ECM). In this study, we were able to obtain novel nanofibrous collagen-GAG scaffolds by electrospinning collagen blended with chondroitin sulfate (CS), a widely used GAG, in a mixed solvent of trifluoroethanol and water. The electrospun collagen-GAG scaffold with 4% CS (COLL-CS-04) exhibited a uniform fiber structure with nanoscale diameters. A second collagen-GAG scaffold with 10% CS consisted of smaller diameter fibers but exhibited a broader diameter distribution due to the different solution properties in comparison with COLL-CS-04. After cross-linking with glutaraldehyde vapor, the collagen-GAG scaffolds became more biostable and were resistant to collagenase degradation. This is evidently a more favorable environment allowing increased proliferation of rabbit conjunctiva fibroblast on the scaffolds. Incorporation of CS into collagen nanofibers without cross-linking did not increase the biostability but still promoted cell growth. The potential of applying the nanoscale collagen-GAG scaffold in tissue engineering is significant since the nanodimension fibers made of natural ECM mimic closely the native ECM found in the human body. The high surface area characteristic of this scaffold may maximize cell-ECM interaction and promote tissue regeneration faster than other conventional scaffolds.
As a programmable biopolymer, DNA has shown great potential in the fabrication and construction o... more As a programmable biopolymer, DNA has shown great potential in the fabrication and construction of nanometer-scale assemblies and devices. In this report, we described a strategy for efficient manipulation of gold nanoparticle-bound DNA using restriction endonuclease. The digestion efficiency of this restriction enzyme was studied by varying the surface coverage of stabilizer, the size of nanoparticles, as well as the distance between the nanoparticle surface and the enzyme-cutting site of particle-bound DNA. We found that the surface coverage of stabilizer is crucial for achieving high digestion efficiency. In addition, this stabilizer surface coverage can be tailored by varying the ion strength of the system. Based on the results of polyacrylamide gel electrophoresis and fluorescent study, a high digestion efficiency of 90+% for particle-bound DNA was achieved for the first time. This restriction enzyme manipulation can be considered as an additional level of control of the particle-bound DNA and is expected to be applied to manipulate more complicated nanostructures assembled by DNA.
Folate or folic acid has been employed as a targeting moiety of various anticancer agents to incr... more Folate or folic acid has been employed as a targeting moiety of various anticancer agents to increase their cellular uptake within target cells since folate receptors are vastly overexpressed in several human tumors. In this study, a biodegradable polymer poly(d,l-lactide-co-glycolide)-poly(ethylene glycol)-folate (PLGA-PEG-FOL) was used to form micelles for encapsulating anticancer drug doxorubicin (DOX). The drug loading content, encapsulation efficiency and in vitro release were characterized. To evaluate the targeting ability of the folate conjugated micelles, the cytotoxicity and cellular uptake of DOX-loaded micelles on three cancer cell lines with different amount of folate receptors (KB, MATB III, C6) and normal fibroblast cells (CCL-110) were compared. The cytotoxicity of PLGA-PEG-FOL micelles to cancer cells was found to be much higher than that of normal fibroblast cells, demonstrating that the folate conjugated micelles has the ability to selectively target to cancer cells. For normal cells, the cellular uptake of PLGA-PEG-FOL micelles was similar to PLGA-PEG micelles without folate conjugation, and was substantially lower than that of cancer cells. In addition, the cell cycle analysis showed that the apoptotic percentage of normal fibroblasts was substantially lower compared with the cancer cells after exposing to DOX-loaded PLGA-PEG-FOL micelles. An optimal folate amount of approximately 40-65% on the micelles was found to be able to kill cancer cells but, at the same time, to have very low effect to normal cells.
... FJ Xu, SP Zhong, LYL Yung, ET Kang,* and KG Neoh. ... The measurements were carried out on a ... more ... FJ Xu, SP Zhong, LYL Yung, ET Kang,* and KG Neoh. ... The measurements were carried out on a variable-angle spectroscopic ellipsometer (model VASE; JA Woollam Inc., Lincoln, NE) at incident angles of 70° and 75° in the wavelength range 200−1000 nm. ...
Self-assembling of metallic nanoparticles to form well-defined nanostructured structures is a fie... more Self-assembling of metallic nanoparticles to form well-defined nanostructured structures is a field that has been receiving considerable research interest in recent years. In this field, DNA is a commonly used linker molecule to direct the assembly of the nanoscale building blocks because of its unique recognition capabilities, mechanical rigidity, and physicochemical stability. This study reported our novel approach to generate gold nanoparticle-DNA conjugates bearing specially designed DNA linker molecules that can be used as building blocks to construct nanoassemblies with precisely controlled structure or as nanoprobes for quantitative DNA sequence detection analysis. In our approach, gold nanoparticle-DNA conjugates bearing a specific number of long double-stranded DNA strands were prepared by gel electrophoresis. A restriction endonuclease enzyme was then used to manipulate the length of the nanoparticle-bound DNA. This enzymatic cleavage was confirmed by gel electrophoresis, and digestion efficiency of 90% or more was achieved. With this approach, nanoparticle conjugates bearing a specific number of strands of short DNA with less than 20-base can be achieved.
The identification of single nucleotide mutations with specific disease and single nucleotide pol... more The identification of single nucleotide mutations with specific disease and single nucleotide polymorphisms (SNPs) among individuals is increasingly important for diagnosis of genetic disease, prediction of disease resistance or predispositions, as well as administration of drug dosages and design of personalized medicine. In this study, we demonstrated a convenient yet useful colorimetric quantitative DNA assay method with high single nucleotide discrimination for both center and end-mismatched sequences. The detection limit of our method is 75 fmol of DNA sample. Even for mixed DNA sample with low percentages of matched targets, this method shows good probe selectivity and zero false positive detection. Finally, the ease of operation and compatibility with existing molecular biology toolbox makes this method a potential low-cost alternative in scientific and clinical diagnostic application.
Impurities in the synthesized gold nanoparticle (AuNP) solution are systematically identified fol... more Impurities in the synthesized gold nanoparticle (AuNP) solution are systematically identified followed by determining an optimal purification process and evaluating the stability as well as oxidation state of the purified 20-nm AuNPs. Quantified non-AuNP components and a newly speciated byproduct (acetate) complete the stoichiometric equation of AuNP synthesis through the citrate reduction method. Among the five tested centrifugation forces (3000e11,000g) and durations (10e60 min), optimal purification of AuNPs was achieved by centrifugation operating at 7000g for 20 min which satisfactorily recovers w80% of AuNPs without detectable impurities. Storage in the dark at 4 C prolongs the stability of the purified AuNP suspensions up to 20 days. AuNPs employed in this study persist in their atomic status without being oxidized, even after they were aerosolized in air or heated at 500 C. This work demonstrates how impurities are identified and removed, and the purified AuNPs can be a reference material to evaluate toxicity or reactivity of other engineered nanomaterials.
Polyurethanes have been synthesized using glycerophosphorylcholine (GPC) as a chain extender. By ... more Polyurethanes have been synthesized using glycerophosphorylcholine (GPC) as a chain extender. By altering the ratio of GPC to butanediol (BD), a series of polymers was obtained composed of different contents of phosphorylcholine. Bulk and surface characterization of the polymers was carried out. Differential scanning calorimetry and dynamic mechanical analysis showed that the polymer with the highest phosphorylcholine content (PU-GPC-20) had the lowest soft segment Tg and the highest tensile strength and Young's modulus among the polymers studied. This is due to the high degree of microphase separation in PU-GPC-20 as a result of by ionic aggregation and hydrogen bonding from the zwitterionic phosphorylcholine moiety. PU-GPC-20 contained approximately 20 wt%, of glycerophosphorylcholine. Dynamic contact angle analysis showed that these polymers, especially the ones with high phosphorylcholine content, rearranged themselves to minimize their interfacial tension upon contacting an aqueous environment. Under shear rates of from 20 to 120 s(-1), neutrophils did not adhere to PU-GPC-20. Under similar conditions neutrophil adhesion was observed only at 20 s(-1) on PU-GPC-10, PU-GPC-5 and on the control polyurethane (PU-base). Cell spreading was observed on the control polyurethane but not on any of the other surfaces. The incorporation of phosphorylcholine into the polyurethane backbone effectively reduced neutrophil adhesion and thus potentially could result in lower inflammatory and foreign body responses.
Adsorbed proteins on biomaterial surfaces determine whether cells adhere, but rheological variabl... more Adsorbed proteins on biomaterial surfaces determine whether cells adhere, but rheological variables are also critical. Neutrophil adhesion under well-de"ned radial #ow conditions was studied on glass preadsorbed with plasma proteins or plasma protein domain fragments. Fibrinogen, low-molecular-weight kininogen (LK), high-molecular-weight kininogen (HK), cleaved HK (HKa), and recombinant HK domains 3 and 5 (D and D & ) were used. The number of adherent cells on the HK and HKa surfaces was less than 10% that found on the "brinogen absorbed surface. The degree of spreading was minimal and detachment of adherent neutrophils was observed. HK and HKa contain binding sites for both anionic surfaces and neutrophils in the same domain (D & ). When adsorbed to surfaces, HK and HKa did not have the neutrophil binding sites available and therefore exhibited an anti-adhesive e!ect. Although D & contains anionic surface binding sites, its small molecular size required a higher number of adsorbed molecules to cover the surface before a signi"cant decrease in cell adhesion was observed. Since LK and D do not possess speci"c anionic surface binding sites, the adsorption of these proteins on glass was very low compared to HK and HKa. Thus, extensive cell adhesion and spreading were observed on the surfaces partially covered with preadsorbed LK and D .
We report an easily visualized liquid crystal (LC)-based system to study the molecular interactio... more We report an easily visualized liquid crystal (LC)-based system to study the molecular interactions between protein-coated gold nanoparticles (AuNPs) and supported phospholipid monolayer selfassembled at the aqueous-LC interface. Protein-coated AuNPs were found to disrupt the phospholipid monolayer and resulted in the orientational transitions of LCs that support the phospholipid layer. The disruption of the phospholipid monolayer depends on the type of protein (albumin, neutravidin, and fibrinogen) adsorbing onto nanoparticles. Furthermore, our results suggest that hydrophobic interaction plays a major role in the disruption of the phospholipid layer by protein-coated AuNPs. Results obtained from this study may offer new understanding in the potential cytotoxicity of nanomaterials, where the interaction between nanoparticles and cell membrane is an important step.
Elemental metal nanoparticles like cadmium and silver are known to cause oxidative stress and are... more Elemental metal nanoparticles like cadmium and silver are known to cause oxidative stress and are also highly toxic. Yet for gold nanoparticles (AuNPs), it is not well established whether these particles are biologically toxic. Here we show that AuNPs, which were taken up by MRC-5 human lung fibroblasts in vitro, induce autophagy concomitant with oxidative stress. We also observed formation of autophagosomes together with the uptake of AuNPs in the lung fibroblasts as well as upregulation of autophagy proteins, microtubule-associated protein 1 light chain 3 (MAP-LC3) and autophagy gene 7 (ATG 7) in treated samples. AuNP treated cells also generated significantly more lipid hydroperoxides (p-value < 0.05), a positive indication of lipid peroxidation. Verification with western blot analysis for malondialdehyde (MDA) protein adducts confirmed the presence of oxidative damage. In addition, AuNP treatment also induced upregulation of antioxidants, stress response genes and protein expression. Exposure to AuNPs is a potential source of oxidative stress in human lung fibroblasts and autophagy may be a cellular defence mechanism against oxidative stress toxicity.
Nanoparticles are increasingly being used for applications in clinical diagnostics due to their u... more Nanoparticles are increasingly being used for applications in clinical diagnostics due to their unique physical and chemical properties. Gold nanoparticles, in particular, have unique optical properties allowing simplicity of detection methods. In this study, an assay based on dimeric assembly of gold nanoparticles was developed for discriminating single nucleotide mismatches. Only gel electrophoresis is needed for assay readout. No other sophisticated or expensive equipment is required. In addition, no false-positive was observed in the readout. We used this assay for genotyping mutations in the Duchenne muscular dystrophy (DMD) gene, the largest known in the human genome. Our results show that conjugating the gold nanoparticles with short DNA probes of 18 bases and 70 bases complimentary to target sequences allows specific discrimination between wild-type and mutant sequences for c.4150G &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; T (NM.004006.1) mutation in exon 30 of the DMD gene using a simple colorimetric detection. This method allows identification of both the patients as well as the carriers of the mutation who are at risk of transmitting the disease.
Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely util... more Collagen and glycosaminoglycan (GAG) are native constituents of human tissues and are widely utilized to fabricate scaffolds serving as an analog of native extracellular matrix (ECM).The development of blended collagen and GAG scaffolds may potentially be used in many soft tissue ...
The development of blended collagen and glycosaminoglycan (GAG) scaffolds can potentially be used... more The development of blended collagen and glycosaminoglycan (GAG) scaffolds can potentially be used in many soft tissue engineering applications since the scaffolds mimic the structure and biological function of native extracellular matrix (ECM). In this study, we were able to obtain novel nanofibrous collagen-GAG scaffolds by electrospinning collagen blended with chondroitin sulfate (CS), a widely used GAG, in a mixed solvent of trifluoroethanol and water. The electrospun collagen-GAG scaffold with 4% CS (COLL-CS-04) exhibited a uniform fiber structure with nanoscale diameters. A second collagen-GAG scaffold with 10% CS consisted of smaller diameter fibers but exhibited a broader diameter distribution due to the different solution properties in comparison with COLL-CS-04. After cross-linking with glutaraldehyde vapor, the collagen-GAG scaffolds became more biostable and were resistant to collagenase degradation. This is evidently a more favorable environment allowing increased proliferation of rabbit conjunctiva fibroblast on the scaffolds. Incorporation of CS into collagen nanofibers without cross-linking did not increase the biostability but still promoted cell growth. The potential of applying the nanoscale collagen-GAG scaffold in tissue engineering is significant since the nanodimension fibers made of natural ECM mimic closely the native ECM found in the human body. The high surface area characteristic of this scaffold may maximize cell-ECM interaction and promote tissue regeneration faster than other conventional scaffolds.
As a programmable biopolymer, DNA has shown great potential in the fabrication and construction o... more As a programmable biopolymer, DNA has shown great potential in the fabrication and construction of nanometer-scale assemblies and devices. In this report, we described a strategy for efficient manipulation of gold nanoparticle-bound DNA using restriction endonuclease. The digestion efficiency of this restriction enzyme was studied by varying the surface coverage of stabilizer, the size of nanoparticles, as well as the distance between the nanoparticle surface and the enzyme-cutting site of particle-bound DNA. We found that the surface coverage of stabilizer is crucial for achieving high digestion efficiency. In addition, this stabilizer surface coverage can be tailored by varying the ion strength of the system. Based on the results of polyacrylamide gel electrophoresis and fluorescent study, a high digestion efficiency of 90+% for particle-bound DNA was achieved for the first time. This restriction enzyme manipulation can be considered as an additional level of control of the particle-bound DNA and is expected to be applied to manipulate more complicated nanostructures assembled by DNA.
Folate or folic acid has been employed as a targeting moiety of various anticancer agents to incr... more Folate or folic acid has been employed as a targeting moiety of various anticancer agents to increase their cellular uptake within target cells since folate receptors are vastly overexpressed in several human tumors. In this study, a biodegradable polymer poly(d,l-lactide-co-glycolide)-poly(ethylene glycol)-folate (PLGA-PEG-FOL) was used to form micelles for encapsulating anticancer drug doxorubicin (DOX). The drug loading content, encapsulation efficiency and in vitro release were characterized. To evaluate the targeting ability of the folate conjugated micelles, the cytotoxicity and cellular uptake of DOX-loaded micelles on three cancer cell lines with different amount of folate receptors (KB, MATB III, C6) and normal fibroblast cells (CCL-110) were compared. The cytotoxicity of PLGA-PEG-FOL micelles to cancer cells was found to be much higher than that of normal fibroblast cells, demonstrating that the folate conjugated micelles has the ability to selectively target to cancer cells. For normal cells, the cellular uptake of PLGA-PEG-FOL micelles was similar to PLGA-PEG micelles without folate conjugation, and was substantially lower than that of cancer cells. In addition, the cell cycle analysis showed that the apoptotic percentage of normal fibroblasts was substantially lower compared with the cancer cells after exposing to DOX-loaded PLGA-PEG-FOL micelles. An optimal folate amount of approximately 40-65% on the micelles was found to be able to kill cancer cells but, at the same time, to have very low effect to normal cells.
... FJ Xu, SP Zhong, LYL Yung, ET Kang,* and KG Neoh. ... The measurements were carried out on a ... more ... FJ Xu, SP Zhong, LYL Yung, ET Kang,* and KG Neoh. ... The measurements were carried out on a variable-angle spectroscopic ellipsometer (model VASE; JA Woollam Inc., Lincoln, NE) at incident angles of 70° and 75° in the wavelength range 200−1000 nm. ...
Self-assembling of metallic nanoparticles to form well-defined nanostructured structures is a fie... more Self-assembling of metallic nanoparticles to form well-defined nanostructured structures is a field that has been receiving considerable research interest in recent years. In this field, DNA is a commonly used linker molecule to direct the assembly of the nanoscale building blocks because of its unique recognition capabilities, mechanical rigidity, and physicochemical stability. This study reported our novel approach to generate gold nanoparticle-DNA conjugates bearing specially designed DNA linker molecules that can be used as building blocks to construct nanoassemblies with precisely controlled structure or as nanoprobes for quantitative DNA sequence detection analysis. In our approach, gold nanoparticle-DNA conjugates bearing a specific number of long double-stranded DNA strands were prepared by gel electrophoresis. A restriction endonuclease enzyme was then used to manipulate the length of the nanoparticle-bound DNA. This enzymatic cleavage was confirmed by gel electrophoresis, and digestion efficiency of 90% or more was achieved. With this approach, nanoparticle conjugates bearing a specific number of strands of short DNA with less than 20-base can be achieved.
The identification of single nucleotide mutations with specific disease and single nucleotide pol... more The identification of single nucleotide mutations with specific disease and single nucleotide polymorphisms (SNPs) among individuals is increasingly important for diagnosis of genetic disease, prediction of disease resistance or predispositions, as well as administration of drug dosages and design of personalized medicine. In this study, we demonstrated a convenient yet useful colorimetric quantitative DNA assay method with high single nucleotide discrimination for both center and end-mismatched sequences. The detection limit of our method is 75 fmol of DNA sample. Even for mixed DNA sample with low percentages of matched targets, this method shows good probe selectivity and zero false positive detection. Finally, the ease of operation and compatibility with existing molecular biology toolbox makes this method a potential low-cost alternative in scientific and clinical diagnostic application.
Impurities in the synthesized gold nanoparticle (AuNP) solution are systematically identified fol... more Impurities in the synthesized gold nanoparticle (AuNP) solution are systematically identified followed by determining an optimal purification process and evaluating the stability as well as oxidation state of the purified 20-nm AuNPs. Quantified non-AuNP components and a newly speciated byproduct (acetate) complete the stoichiometric equation of AuNP synthesis through the citrate reduction method. Among the five tested centrifugation forces (3000e11,000g) and durations (10e60 min), optimal purification of AuNPs was achieved by centrifugation operating at 7000g for 20 min which satisfactorily recovers w80% of AuNPs without detectable impurities. Storage in the dark at 4 C prolongs the stability of the purified AuNP suspensions up to 20 days. AuNPs employed in this study persist in their atomic status without being oxidized, even after they were aerosolized in air or heated at 500 C. This work demonstrates how impurities are identified and removed, and the purified AuNPs can be a reference material to evaluate toxicity or reactivity of other engineered nanomaterials.
Polyurethanes have been synthesized using glycerophosphorylcholine (GPC) as a chain extender. By ... more Polyurethanes have been synthesized using glycerophosphorylcholine (GPC) as a chain extender. By altering the ratio of GPC to butanediol (BD), a series of polymers was obtained composed of different contents of phosphorylcholine. Bulk and surface characterization of the polymers was carried out. Differential scanning calorimetry and dynamic mechanical analysis showed that the polymer with the highest phosphorylcholine content (PU-GPC-20) had the lowest soft segment Tg and the highest tensile strength and Young&#39;s modulus among the polymers studied. This is due to the high degree of microphase separation in PU-GPC-20 as a result of by ionic aggregation and hydrogen bonding from the zwitterionic phosphorylcholine moiety. PU-GPC-20 contained approximately 20 wt%, of glycerophosphorylcholine. Dynamic contact angle analysis showed that these polymers, especially the ones with high phosphorylcholine content, rearranged themselves to minimize their interfacial tension upon contacting an aqueous environment. Under shear rates of from 20 to 120 s(-1), neutrophils did not adhere to PU-GPC-20. Under similar conditions neutrophil adhesion was observed only at 20 s(-1) on PU-GPC-10, PU-GPC-5 and on the control polyurethane (PU-base). Cell spreading was observed on the control polyurethane but not on any of the other surfaces. The incorporation of phosphorylcholine into the polyurethane backbone effectively reduced neutrophil adhesion and thus potentially could result in lower inflammatory and foreign body responses.
Adsorbed proteins on biomaterial surfaces determine whether cells adhere, but rheological variabl... more Adsorbed proteins on biomaterial surfaces determine whether cells adhere, but rheological variables are also critical. Neutrophil adhesion under well-de"ned radial #ow conditions was studied on glass preadsorbed with plasma proteins or plasma protein domain fragments. Fibrinogen, low-molecular-weight kininogen (LK), high-molecular-weight kininogen (HK), cleaved HK (HKa), and recombinant HK domains 3 and 5 (D and D & ) were used. The number of adherent cells on the HK and HKa surfaces was less than 10% that found on the "brinogen absorbed surface. The degree of spreading was minimal and detachment of adherent neutrophils was observed. HK and HKa contain binding sites for both anionic surfaces and neutrophils in the same domain (D & ). When adsorbed to surfaces, HK and HKa did not have the neutrophil binding sites available and therefore exhibited an anti-adhesive e!ect. Although D & contains anionic surface binding sites, its small molecular size required a higher number of adsorbed molecules to cover the surface before a signi"cant decrease in cell adhesion was observed. Since LK and D do not possess speci"c anionic surface binding sites, the adsorption of these proteins on glass was very low compared to HK and HKa. Thus, extensive cell adhesion and spreading were observed on the surfaces partially covered with preadsorbed LK and D .
We report an easily visualized liquid crystal (LC)-based system to study the molecular interactio... more We report an easily visualized liquid crystal (LC)-based system to study the molecular interactions between protein-coated gold nanoparticles (AuNPs) and supported phospholipid monolayer selfassembled at the aqueous-LC interface. Protein-coated AuNPs were found to disrupt the phospholipid monolayer and resulted in the orientational transitions of LCs that support the phospholipid layer. The disruption of the phospholipid monolayer depends on the type of protein (albumin, neutravidin, and fibrinogen) adsorbing onto nanoparticles. Furthermore, our results suggest that hydrophobic interaction plays a major role in the disruption of the phospholipid layer by protein-coated AuNPs. Results obtained from this study may offer new understanding in the potential cytotoxicity of nanomaterials, where the interaction between nanoparticles and cell membrane is an important step.
Elemental metal nanoparticles like cadmium and silver are known to cause oxidative stress and are... more Elemental metal nanoparticles like cadmium and silver are known to cause oxidative stress and are also highly toxic. Yet for gold nanoparticles (AuNPs), it is not well established whether these particles are biologically toxic. Here we show that AuNPs, which were taken up by MRC-5 human lung fibroblasts in vitro, induce autophagy concomitant with oxidative stress. We also observed formation of autophagosomes together with the uptake of AuNPs in the lung fibroblasts as well as upregulation of autophagy proteins, microtubule-associated protein 1 light chain 3 (MAP-LC3) and autophagy gene 7 (ATG 7) in treated samples. AuNP treated cells also generated significantly more lipid hydroperoxides (p-value < 0.05), a positive indication of lipid peroxidation. Verification with western blot analysis for malondialdehyde (MDA) protein adducts confirmed the presence of oxidative damage. In addition, AuNP treatment also induced upregulation of antioxidants, stress response genes and protein expression. Exposure to AuNPs is a potential source of oxidative stress in human lung fibroblasts and autophagy may be a cellular defence mechanism against oxidative stress toxicity.
Nanoparticles are increasingly being used for applications in clinical diagnostics due to their u... more Nanoparticles are increasingly being used for applications in clinical diagnostics due to their unique physical and chemical properties. Gold nanoparticles, in particular, have unique optical properties allowing simplicity of detection methods. In this study, an assay based on dimeric assembly of gold nanoparticles was developed for discriminating single nucleotide mismatches. Only gel electrophoresis is needed for assay readout. No other sophisticated or expensive equipment is required. In addition, no false-positive was observed in the readout. We used this assay for genotyping mutations in the Duchenne muscular dystrophy (DMD) gene, the largest known in the human genome. Our results show that conjugating the gold nanoparticles with short DNA probes of 18 bases and 70 bases complimentary to target sequences allows specific discrimination between wild-type and mutant sequences for c.4150G &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; T (NM.004006.1) mutation in exon 30 of the DMD gene using a simple colorimetric detection. This method allows identification of both the patients as well as the carriers of the mutation who are at risk of transmitting the disease.
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Papers by Lanry Yung