Large-Area Nanolithography for the Development of Bioelectrocatalytic Systems

Abstract

The work in this thesis centres on bridging the world of enzymology and nanofabrication for the generation of biodevices, which have a plethora of downstream applications, including sensing, diagnostics and energy conversion. To increase the commercial viability of such biodevices, the use of fabrication methods at the large scale (100s cm2 area) is crucial, but their potential is yet to be fully explored. Firstly, the work presented here includes the overexpression in Escherichia coli of a multicopper oxidase (laccase) CotA from the extremophilic bacteria Bacillus subtilis, and the development of an analytical method to evaluate its copper content. Subsequently, CotA was integrated into nanoscale arrays produced with different lithographic methods suitable for small-area (~ 1 cm2) and large-area (> 300 cm2) fabrication, proving that enzymes selectively immobilised on the nanofeatures gave essentially the same activity per area regardless of the lithographic method used. Antibiofouling coatings for the bulk (unpatterned) areas of titania in the large-area nanoarrays were investigated, and a decrease of non-specific protein adsorption of up to 74 % could be achieved in the best cases. Finally, the electrochemical performances of the CotA functionalised nanoarrays were tested. Immobilised CotA was found to reduce O2 via mediated electron transfer, showing that site-selective immobilisation of the enzyme in an oriented and covalent manner substantially improves the current produced and the stability of the system compared to randomly adsorbed CotA.

Date of Award	15 Dec 2022
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Peter Quayle (Co Supervisor), Lu Shin Wong (Main Supervisor) & Christopher Blanford (Co Supervisor)