title: A paramagnetic-reporter two-particle system for amplification-free detection of DNA in serum.
abstract: Quantitative nucleic acid detection is used extensively in the management of many pathogenic infections, where viral or bacterial nucleic acid copy number relates directly to disease prognosis. Temperature-cycle or isothermal amplification formats offer excellent performance, but their requirement for purified nucleic acid and accurate temperature control increases costs and renders their migration to resource-limited environments problematic. In contrast, amplification-free nucleic acid assays could allow simplified system design, resulting in reduced costs. In this study, we report a amplification-free herpes simplex virus (HSV) assay where oligoethylene glycol methacrylate (OEGMA) grafted ssDNA capture-probes on paramagnetic nanoparticles are coupled with reporter-probe-modified fluorescent nanoparticles in a target-dependent manner. Following assay and reagent optimization, a sub-pM (25 amol) limit of detection could be achieved in buffer and also in neat, undiluted serum, representing a 160-fold improvement over that achieved using convention detection with a fluorescence plate reader. Equivalent performance in serum and buffer offers the opportunity for simplified diagnostic device design for resource-limited environments.
authors: Institute for Molecular Bioscience, 306 Carmody Road, University of Queensland, Brisbane 4072, QLD, Australia; Australian Institute for Bioengineering and Nanotechnology, Corner College and Cooper Roads, University of Queensland, Brisbane 4072 QLD, Australia.
authors: David A C
authors: DA
authors: Thomson
authors: Matthew A
authors: MA
authors: Cooper
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D057930:Click Chemistry; D004279:DNA, Viral / Q000097:blood*; D005456:Fluorescent Dyes / Q000737:chemistry; D006561:Herpes Simplex / Q000097:blood / Q000175:diagnosis; D006801:Humans; D057230:Limit of Detection; D008689:Methacrylates / Q000737:chemistry; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D018139:Simplexvirus / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004279:DNA, Viral; D005456:Fluorescent Dyes; D008689:Methacrylates; C005044:hydroxyethyl methacrylate
keywords: Amplification-free; Click chemistry; Diagnostic; Microfluidic; Polymer brush; Serum