Sol-Gel Derived Nanostructured Metal Oxide Platform for Bacterial Detection

O1 gene based 24-mer single stranded deoxyribonucleic acid probe (ssDNA) has been immobilized onto sol-gel derived nanostructured zirconium oxide (NanoZrO(2)) film fabricated onto indium-tin-oxide (ITO) coated glass plate to detect Vibrio cholerae. The X-ray diffraction and Atomic Force Microscopy techniques have been used to characterize the nanostructured ZrO(2) (particle size of similar to 30-40 nm) and the ssDNA/ZrO(2) bioelectrode. The hybridization of ssDNA/ZrO(2) bioelectrode with the complementary and genomic DNA has been investigated using differential pulse voltammetry. The results of electrochemical studies suggest that electro-active and cationic NanoZrO(2) provides an effective surface to bind with the phosphate group of DNA resulting in enhanced electron transport. The ssDNA/NanoZrO(2) bioelectrode shows a detection range from 1 x 10(-8) to 10 nM of complementary DNA of V. cholerae within 60 s of hybridization time at 25 degrees C using methylene blue as an electroactive indicator. This O1 gene based metal oxide (ZrO(2)) sensor exhibits sensitivity for ssDNA/NanoZrO(2)/ITO bioelectrode as 0.48 mu A/nM cm(-2) for complementary DNA and 2.34 mu A/nM cm(-2) for genomic DNA with regression coefficients (R) of 0.991 and 0.995, respectively. This DNA bioelectrode is stable for about 15 weeks when stored at 4 degrees C.