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ABSTRACT: Monoclonal antibody-conjugated popcorn-shape gold nanotechnology-driven approach to selectively detect multiple drug resistant (MDRB) Salmonella typhimurium DT104 bacteria has been developed. We demonstrate that the gold nanotechnology based assay is capable of measuring the amount of MDRB in food samples.
Chemical Communications 09/2011; 47(33):9444-6. · 6.17 Impact Factor
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ABSTRACT: Cyanide is an extremely toxic lethal poison known to humankind. Developing rapid, highly sensitive, and selective detection of cyanide from water samples is extremely essential for human life safety. Driven by the need, here we report a gold-nanoparticle-based label-free surface-enhanced Raman spectroscopy (SERS) system for highly toxic cyanide ion recognition in parts-per-trillion level and to examine gold-nanoparticle-cyanide interaction. We have shown that the SERS assay can be used to probe the gold nanoparticle dissociation process in the presence of cyanide ions. Our experimental data indicates that gold-nanoparticle-based SERS can detect cyanide from a water sample at the 110 ppt level with excellent discrimination against other common anions and cations. The results also show that the SERS probe can be used to detect cyanide from environmental samples.
Chemistry 07/2011; 17(30):8445-51. · 5.93 Impact Factor
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ABSTRACT: A recent gold nanotechnology-driven approach opens up a new possibility for the destruction of cancer cells through photothermal therapy. Ultimately, photothermal therapy may enter into clinical therapy and, as a result, there is an urgent need for techniques to monitor the tumor response to therapy. Driven by this need, a nanoparticle surface-energy-transfer (NSET) approach to monitor the photothermal therapy process by measuring a simple fluorescence intensity change is reported. The fluorescence intensity change is due to the light-controlled photothermal release of single-stranded DNA/RNA via dehybridization during the therapy process. Time-dependent results show that just by measuring the fluorescence intensity change, the photothermal therapy response during the therapy process can be monitored. The possible mechanism and operating principle of the NSET assay are discussed. Ultimately, this NSET assay could have enormous potential applications in rapid, on-site monitoring of the photothermal therapy process, which is critical to providing effective treatment of cancer and multidrug-resistant bacterial infections.
Small 07/2011; · 8.35 Impact Factor
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10/2010; , ISBN: 9783527610419
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ABSTRACT: Salmonella bacteria are the major cause for the infection of 16 million people worldwide with typhoid fever each year. Antibiotic-resistant Salmonella strains have been isolated from various food products. As a result, the development of ultrasensitive sensing technology for detection and new approaches for the treatment of infectious bacterial pathogens that do not rely on traditional therapeutic regimes is very urgent for public health, food safety, and the world economy. Driven by this need, we report herein a nanotechnology-driven approach that uses antibody-conjugated oval-shaped gold nanoparticles to selectively target and destroy pathogenic bacteria. Our experiments have shown the use of a simple colorimetric assay, with an anti-salmonella antibody conjugated to oval-shaped gold nanoparticles, for the label-free detection of S. typhimurium with an excellent detection limit (10(4) bacteria per mL) and high selectivity over other pathogens. When bacteria conjugated to oval-shaped gold nanoparticles were exposed to near-infrared radiation, a highly significant reduction in bacterial cell viability was observed due to photothermal lysis. Ideally, this nanotechnology-based assay would have enormous potential for rapid, on-site pathogen detection to avoid the distribution of contaminated foods.
Chemistry 05/2010; 16(19):5600-6. · 5.93 Impact Factor
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ABSTRACT: Breast cancer is the most common cancer among women, and it is the second leading cause of cancer deaths in women today. The key to the effective and ultimately successful treatment of diseases such as cancer is early and accurate diagnosis. Driven by the need, in this article, we report for the first time a simple colorimetric and highly sensitive two-photon scattering assay for highly selective and sensitive detection of breast cancer SK-BR-3 cell lines at a 100 cells/mL level using a multifunctional (monoclonal anti-HER2/c-erb-2 antibody and S6 RNA aptamer-conjugated) oval-shaped gold-nanoparticle-based nanoconjugate. When multifunctional oval-shaped gold nanoparticles are mixed with the breast cancer SK-BR-3 cell line, a distinct color change occurs and two-photon scattering intensity increases by about 13 times. Experimental data with the HaCaT noncancerous cell line, as well as with MDA-MB-231 breast cancer cell line, clearly demonstrated that our assay was highly sensitive to SK-BR-3 and it was able to distinguish from other breast cancer cell lines that express low levels of HER2. The mechanism of selectivity and the assay's response change have been discussed. Our experimental results reported here open up a new possibility of rapid, easy, and reliable diagnosis of cancer cell lines by monitoring the colorimetric change and measuring TPS intensity from multifunctional gold nanosystems.
ACS Nano 02/2010; 4(3):1739-49. · 10.77 Impact Factor
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ABSTRACT: Alzheimer's disease (AD) is a progressive mental disorder disease, which affects 26.6 million people worldwide and estimated increments can be 100 millions by 2050. Since there is no cure at present, early diagnosis of AD is crucial for the current drug treatments. Driven by the need, here we demonstrate for the first time that monoclonal anti-tau antibody-coated gold nanoparticle based two-photon scattering assay can be used for the detection of Alzheimer's tau protein in the 1 pg/mL level which is about 2 orders of magnitude lower than cutoff values (195 pg/mL) for tau protein in CSF (cerebrospinal fluid). We have shown that when anti-tau antibody-coated gold nanoparticles were mixed with 20 ng/mL of tau protein, two-photon Rayleigh scattering intensity (TPRS) increases by about 16 times. The mechanism of TPRS intensity change has been discussed. Our data demonstrated that our TPRS assay is highly sensitive to tau protein and it can distinguish from BSA, which is one of the most abundant protein components in CSF. Our results demonstrate the potential for a broad application of this type of nanobionanotechnology in practical biomedical applications.
ACS Nano 09/2009; 3(9):2834-40. · 10.77 Impact Factor
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ABSTRACT: The presence of E. coli in foodstuffs and drinking water is a chronic worldwide problem. The worldwide food production industry is worth about U.S. $578 billion, and the demand for biosensors to detect pathogens and pollutants in foodstuffs is growing day by day. Driven by the need, we report for the first time that two-photon Rayleigh scattering (TPRS) properties of gold nanorods can be used for rapid, highly sensitive and selective detection of Escherichia coli bacteria from aqueous solution, without any amplification or enrichment in 50 colony forming units (cfu)/mL level with excellent discrimination against any other bacteria. TPRS intensity increases 40 times when anti- E. coli antibody-conjugated nanorods were mixed with various concentrations of Escherichia coli O157:H7 bacterium. The mechanism of TPRS intensity change has been discussed. This bionanotechnology assay could be adapted in studies using antibodies specific for various bacterial pathogens for the detection of a wide variety of bacterial pathogens used as bioterrorism agents in food, clinical samples, and environmental samples.
ACS Nano 08/2009; 3(7):1906-12. · 10.77 Impact Factor
