Micro and Nanoscale Fabrication and Characterization for Next-Generation Biosensors

In this talk, our work on the fabrication and characterization of two next-generation biosensors is presented. The first device we fabricated is a sequence-specific nucleic acid sensor based on the blockage of a nanopore. Current methods for nucleic acid detection rely on polymerase chain reaction (PCR) and fluorescent labeling, however, these methods render the devices to be slow, expensive, complex, and bulky. In order to address these limitations, a glass nanopore in a thin glass membrane was fabricated. By scaling down the pore diameter to the nanoscale, 1 aM detection of 16S rRNA from Escherichia coli was demonstrated, thus showing the potential to detect pathogens in body fluids, food, or water. The second device we developed was an implantable microprobe for neurotransmitter sensing. We were able to improve the performance and consistency by transferring enzymes by polydimethylsiloxane (PDMS) microcontact printing with alignment onto the microprobe. Model enzymes, choline oxidase (ChOx) and glucose oxidase (GOx) were transferred onto microelectrodes by PDMS stamping with alignment to exploit dual sensing (glucose and choline) capabilities for in vivo applications. The method we developed using PDMS stamping demonstrated the ability to immobilize selective enzymes on microelectrodes array with high throughput.