Concentration effect of graphene oxide on affinity-prepared bacteriorhodospin photoelectric chip

• Main Authors: Cheng-De Lin, 林承德
• Other Authors: Hsiu-Mei Chen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/64hx74

碩士 === 國立臺灣科技大學 === 化學工程系 === 102 === Graphene oxide (GO) has unique properties and has recently become a research focus. Purple membrane (PM) is the cellular membrane of archaeon Halobacterium salinarum, which contains bacteriorhodopsin with a unidirectional light-driven proton pump ability. This research applied GO to PM-chip technology and employed water contact angle, CW differential photocurrent, pulse-laser fast photocurrent, Fourier transform infrared spectroscopy (FTIR), protein quantification, and fluorescence analyses to examine the GO effects. Self-assembled-monolayer (SAM) fabricated ITO was first coated with either activated avidin or its mixture with GO and used as linkers to immobilize biotinylated PM (b-PM) through affinity adsorption. The contact angle of clean ITO was 5~8?a, rose to ~30?a after SAM fabrication, and further increased to ~65?a following the coating with either activated avidin or its mixture with GO. The contact angle gradually decreased to ~15?a with the increased addition of GO and was maintained at ~30?a if b-PM had been successfully captured. A minor addition of GO caused insignificant effects on the differential photocurrent response of the as-prepared PM chips, while the response was almost completely inhibited with the result of only 5% residual activity when the GO addition concentration was increased and reached a critical value. Upon pulse-laser illumination, the chips prepared with the addition of GO generated a higher B1 fast photocurrent response with a better success rate than the chips prepared without GO, implying an improvement of the orientation uniformity of immobilized b-PM. FTIR analysis of the mixture of activated avidin and GO revealed augmentation of hydrogen binding as well as C-N stretching, suggesting hydrogen and covalent linkages between them. BCA protein analysis showed that 20% more activated avidin could be retained in dialysis tubes if GO had been added. Furthermore, there is no red shift of the fluorescence spectra of activated avidin when GO was present. Therefore, this study suggested the functional linkages between activated avidin and GO and demonstrated the feasibility of applying their mixture as a linker for b-PM affinity immobilization with little effects on PM activity but improvement of PM orientation uniformity.