Date of Award

7-1-2020

Thesis Type

phd

Document Type

Thesis (Restricted Access)

Divisions

eng

Department

Faculty of Engineering

Institution

Universiti Malaya

Abstract

Carbon, the building block life, is rapidly becoming the building block of nextgeneration electronics and sensor materials. Of many ways to handle nanocarbon materials, Carbon Microelectromechanical Systems (C-MEMS) emerges as a unique way for top-down fabrication of three-dimensional carbon micro to nanostructures. In this work, the use of C-MEMS techniques in nanowire biosensor fabrication is explored. Two main hindrances in the use of C-MEMS carbon structures for biosensing lie in miniaturization to nanoscale sensor material and inertness of as-fabricated carbon. This dissertation presents ways to overcome these limitations. First, miniaturization to patterned sub-100 nm carbon nanowires was achieved by optimization of ectrospinning properties and integration of electrospinning photoresist polymer with photolithographic pelatterning. Secondly, a microplasma direct writing technique was developed as a novel non-destructive technique for selective surface functionalization of C-MEMS manufactured carbon electrodes. This method uses a simple setup to pattern carboxylic functional groups on the carbon surface at atmospheric conditions. Surface oxygen percentage as high as 27% has been observed. The fabricated suspended carbon nanowires were integrated with microfluidics and immobilized with biomolecular probes for biosensing. Nanowire biosensing was demonstrated by developing an aptamer-based assay that can detect whole-cell Salmonella. The carbon nanowire biosensor used chemiresistive biosensing to achieve rapid detection of the pathogen with high sensitivity and specificity with a detection limit of 10 CFU/mL, which is more sensitive than conventional methods of detecting bacteria.

Note

Thesis (PhD) - Faculty of Engineering, Universiti Malaya, 2020.

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