title: Detection of non-PCR amplified S. enteritidis genomic DNA from food matrices using a gold-nanoparticle DNA biosensor: a proof-of-concept study.
abstract: Bacterial pathogens pose an increasing food safety and bioterrorism concern. Current DNA detection methods utilizing sensitive nanotechnology and biosensors have shown excellent detection, but require expensive and time-consuming polymerase chain reaction (PCR) to amplify DNA targets; thus, a faster, more economical method is still essential. In this proof-of-concept study, we investigated the ability of a gold nanoparticle-DNA (AuNP-DNA) biosensor to detect non-PCR amplified genomic Salmonella enterica serovar Enteritidis (S. enteritidis) DNA, from pure or mixed bacterial culture and spiked liquid matrices. Non-PCR amplified DNA was hybridized into sandwich-like structures (magnetic nanoparticles/DNA/AuNPs) and analyzed through detection of gold voltammetric peaks using differential pulse voltammetry. Our preliminary data indicate that non-PCR amplified genomic DNA can be detected at a concentration as low as 100 ng/mL from bacterial cultures and spiked liquid matrices, similar to reported PCR amplified detection levels. These findings also suggest that AuNP-DNA biosensors are a first step towards a viable detection method of bacterial pathogens, in particular, for resource-limited settings, such as field-based or economically limited conditions. Future efforts will focus on further optimization of the DNA extraction method and AuNP-biosensors, to increase sensitivity at lower DNA target concentrations from food matrices comparable to PCR amplified DNA detection strategies.
authors.affiliation: Department of Biology, Whittier College, 13406 E. Philadelphia St., Whittier, CA 90608, USA. svetrone@whittier.edu
authors.forename: Sylvia A
authors.initials: SA
authors.lastname: Vetrone
authors.forename: Michael C
authors.initials: MC
authors.lastname: Huarng
authors.forename: Evangelyn C
authors.initials: EC
authors.lastname: Alocilja
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004269:DNA, Bacterial / Q000032:analysis* / Q000302:isolation & purification*; D005516:Food Microbiology / Q000295:instrumentation / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012477:Salmonella enteritidis / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial; D006046:Gold
keywords: DNA probe; biosensor; food matrix; genomic DNA; gold-nanoparticles