title: Colorimetric biosensing of targeted gene sequence using dual nanoparticle platforms.
abstract: We have developed a colorimetric biosensor using a dual platform of gold nanoparticles and graphene oxide sheets for the detection of Salmonella enterica. The presence of the invA gene in S. enterica causes a change in color of the biosensor from its original pinkish-red to a light purplish solution. This occurs through the aggregation of the primary gold nanoparticles-conjugated DNA probe onto the surface of the secondary graphene oxide-conjugated DNA probe through DNA hybridization with the targeted DNA sequence. Spectrophotometry analysis showed a shift in wavelength from 525 nm to 600 nm with 1 μM of DNA target. Specificity testing revealed that the biosensor was able to detect various serovars of the S. enterica while no color change was observed with the other bacterial species. Sensitivity testing revealed the limit of detection was at 1 nM of DNA target. This proves the effectiveness of the biosensor in the detection of S. enterica through DNA hybridization.
authors.affiliation: Low Dimension Material Research Center, Department of Physics, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Jeevan
authors.initials: J
authors.lastname: Thavanathan
authors.affiliation: Low Dimension Material Research Center, Department of Physics, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Nay Ming
authors.initials: NM
authors.lastname: Huang
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Kwai Lin
authors.initials: KL
authors.lastname: Thong
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D004247:DNA / Q000032:analysis; D015342:DNA Probes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D015342:DNA Probes; D006046:Gold; D006108:Graphite; D004247:DNA
keywords: DNA hybridization; DNA probe; Salmonella enterica; biosensor; gold nanoparticles; graphene oxide