Biotin self-assembled monolayer for impedimetric genosensor for direct detection of HIV-1

•Self-assembled monolayer on biotinylated oligonucleotide gold.•Label-free impedimetric detection of DNA hybridization.•Impedimetric detection for HIV-1 proviral DNA. This study was performed to prove the feasibility of a direct impedimetric DNA genosensor by using biotin self-assembled monolayer (SAM). The sensor was composed of a gold rod with a SAM of biotin-modified 19-base oligonucleotide probe (5´-AAA GAT TAA TCC TGG G -3´,) for HIV-1. The electrode modification was characterized by Surface-Enhancement Raman Spectroscopy (SERS), cyclic voltammetry and the hybridization with the complementary oligonucleotide was monitored by impedimetric technique. SERS was used to confirm the linking of Biotin-DNA on the surface of the Au electrode. The coverage was 89% of the surface and a concentration of complementary oligonucleotides of 2.5 10−12 molL−1 could be detected. [Display omitted]