Modified Surface of Titanium Dioxide Nanoparticles-Based Biosensor for DNA Detection

摘要

A new technique was used to develop a simple and selective picoammeter DNA biosensor for identification of E. coli 0157:H7. This biosensor was fabricated from titanium dioxide nanoparticles that was synthesized by sol-gel method and spin-coated on silicon dioxide substrate via spinner. 3-Aminopropyl triethoxy silane (APTES) was used to modify the surface of TiO_2. Simple surface modification approach has been applied; which is single dropping of APTES onto the TiO_2 nanoparticles surface. Carboxyl modified probe DNA has been bind onto the surface of APTES/TiO_2 without any amplifier element. Electrical signal has been used as the indicator to differentiate each step (surface modification of TiO_2 and probe DNA immobilization). The I—V measurements indicate extremely low current (pico-ampere) flow through the device which is 2.8138E-10 A for pure TiO_2 nanoparticles, 2.8124E-10 A after APTES modification and 3.5949E-10 A after probe DNA immobilization.