Discovery of ZnO-Binding Peptides for Photocatalytic Material Synthesis
Authors:Chung Hee Moon, Marzieh Tousi
Mentor:Elaine Haberer, Assistant Professor, Electrical Engineering Department, University of California, Riverside
Clean air and water are important for sustainable habitats. Improved methods for maintaining and renewing these resources are critical. Photocatalysis is a promising technology for removal of toxic molecules and pollutants from air and water. Photocatalysis utilizes sunlight to activate photosensitive materials to catalyze chemical reactions necessary to degrade pollutants into innocuous compounds. Nanoscale zinc oxide (ZnO) displays optical and electrical properties suitable for photocatalysis. Furthermore, unlike other conventional methods, nanoscale biomineralized ZnO is advantageously manufactured under ambient conditions. The objective of this study was to find a specific peptide that binds to ZnO, with the possibility to biomineralize nanostructures of ZnO in the future. Biopanning, a combinatorial phage display technique with phages displaying approximately 107 different peptides, was used to select peptide sequences with affinity for ZnO. After five rounds of biopanning, two phages which showed strong affinity for ZnO were isolated. The peptides VPGAAEHT and DRQVDATA were displayed on these phages. To confirm the affinity of these phages for ZnO, binding tests were completed using a ZnO thin film grown on a silicon substrate as the target material. The identified phages, displaying VPGAAEHT and DRQVDATA peptides, were 79 and 61 times more likely to bind to the ZnO thin film on a silicon substrate target than the wild-type control phage, respectively. Binding studies were also performed using the silicon substrate as a target to ensure the phage affinity was for the ZnO thin film rather than the silicon substrate. The VPGAAEHT phage demonstrated an affinity for the ZnO thin film which was more than twice that observed for the silicon substrate alone, whereas the DRQVDATA phage showed a comparable affinity for both the ZnO thin film and the silicon substrate. These results will benefit future research to biomineralized nanostructured ZnO material which could be used for photocatalytic devices.