ZINC OXIDE NANORODS AS AN INTRACELLULAR pH SENSOR

pH measurements using two kind of samples, namely zinc oxide (ZnO) nanorods of 300nm in diameter and 10µm in length grown on 2D macro-porous periodic structures (2DMPPS) and plane n-Si substrates and ZnO nanorods of 60nm in diameter and 500nm in length grown on the silver coated tip of glass capillary (D=0.7µm). We found that the sensitivity of ZnO nanorods increases with reductions in size from (35mV/pH for D=300nm and L=10µm) to (58mV/pH for D=50nm and L=1µm) using the site binding model. The potential difference for the ZnO nanorods electrode vs. Ag/AgCl electrode showed a high sensitivity range for ZnO nanorods grown on 2DMPPS n-Si, as compared to plane n-Si, and had a sensitivity equal to 51.88mV/pH at 22oC for the ZnO on the capillary tip for pH (4-12) in buffer solutions. Vertically nanoelectrodes of this type can be applied to penetrate a single living cell without causing cell apoptosis