Nonenzymatic Detection of Bacterial Genomic DNA Using the Bio Bar Code Assay

Department of Chemistry, Northwestern University, Evanston, Illinois, United States
Analytical Chemistry (Impact Factor: 5.64). 01/2008; 79(23):9218-23. DOI: 10.1021/ac701626y
Source: PubMed


The detection of bacterial genomic DNA through a nonenzymatic nanomaterials-based amplification method, the bio bar code assay, is reported. The assay utilizes oligonucleotide-functionalized magnetic microparticles to capture the target of interest from the sample. A critical step in the new assay involves the use of blocking oligonucleotides during heat denaturation of the double-stranded DNA. These blockers bind to specific regions of the target DNA upon cooling and prevent the duplex DNA from rehybridizing, which allows the particle probes to bind. Following target isolation using the magnetic particles, oligonucleotide-functionalized gold nanoparticles act as target recognition agents. The oligonucleotides on the nanoparticle (bar codes) act as amplification surrogates. The bar codes are then detected using the Scanometric method. The limit of detection for this assay was determined to be 2.5 fM, and this is the first demonstration of a bar code-type assay for the detection of double-stranded, genomic DNA.

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Available from: Rafael A Vega, Jun 13, 2014
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    • "Until now, some methods have been reported by integrating the advantages of MBs and AuNPs in immunoassay. [14] [15] [18] [19] In addition to integrating the advantages of MBs and AuNPs, these methods share another important common characteristic – the target substances are large molecules such as AFP, [15] IgG [14] or at least has two epitopes to be bound. Briefly, sandwich immunoassay is the core mode of these methods, which makes integration of the advantageous properties of MBs and AuNPs in immunoassay possible. "
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    • "These are bare spherical AuNPs without further surface modifications with unique optical properties [7]. AuNP based colorimetric biosensors, because of the visible color change have been used as real time detection of DNA and small molecules [1] [8] [9]. Different electrostatic properties of single stranded DNA (ss-DNA), double stranded DNA (ds-DNA) and folded (e.g. "

    Full-text · Conference Paper · Mar 2012
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    • "Metal nanoparticles have gained significant interest in materials science, as controlling shape and size confers them with unique physio-chemical properties that have direct impacts on their use in molecular diagnostics (Hill and Mirkin 2006; Thaxton, Georganopoulou et al. 2006; Hill, Vega et al. 2007; Seferos, Giljohann et al. 2007), catalysis (Shiraishi and Toshima 1999; Astruc, Lu et al. 2005; Somorjai, Tao et al. 2008), electronics (Schmid and Corain 2003; Somorjai, Tao et al. 2008), photonics (Millstone, Hurst et al. 2009), biological tagging (Thaxton, Georganopoulou et al. 2006) and surface enhanced Raman scattering (Dick, McFarland et al. 2001; Chen, Wang et al. 2007) applications. There have been efforts to synthesize metal nanoparticles with considerable success, but they are largely limited to chemical methods (Parikh, Singh et al. 2008; Millstone, Hurst et al. 2009). "
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    ABSTRACT: Metal nanoparticles have gained significant interest in the past decade because of their unique physio-chemical properties which has a potential to be used in a wide range of applications. Recent efforts have gained success in synthesising nanoparticles with excellent shape and size control; however they are largely restricted to chemical methods. There is an increasing focus on eco-friendly 'green' routes for the production of metal nanoparticles, e.g. using biological entities. Morganella sp., a known silver resistant bacterium, was recently reported by our group to produce anisotropic silver nanoparticles by controlling the bacterial growth kinetics. Interestingly, due to structural similarity between silver and copper ions, bacteria that are silver resistant might also be able to uptake copper ions which can then be reduced to synthesize copper nanoparticles. Although similarities in the resistance machinery for silver and copper have been established, their role in synthesizing copper nanoparticles is not well understood. In an effort to synthesize copper nanoparticles via a green biological route, we herein demonstrate for the first time that exposing silver resistant bacteria Morganella sp. to Cu +2 ions can enable aqueous phase synthesis of Cu nanoparticles. The results obtained were characterized using a wide range of techniques such as TEM, HR-TEM, UV-vis spectroscopy and XPS.
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