Nanodevices for biosensing applications

Abstract

This research discusses the development of biosensors with vertically aligned nanowires, and the evaluation of their physical properties, electrochemical performance and biocompatibility. The developments include neurotransmitter (dopamine) sensors, glucose sensors for continuous monitoring, potassium ion sensors and integration of those sensors. A hemi-cylindrical nanocavity structure has been developed for dopamine sensing using redox cycling with radial diffusion within the cavities. By immobilization of enzymes in a conducting polymer matrix on vertically aligned nanowires, glucose sensing electrodes have been obtained with high sensitivity and selectivity. In addition, potassium sensing, potentially useful for monitoring changes of extracellular potassium concentration during myocardial ischemia, has been demonstrated using ion selective membranes (ISM) on nanowires. Sensor developments and measurement results are included in the presentation along with descriptions of top-down and bottom-up nano-/micro-fabrication technologies such as lithography and thin film deposition.

Synthesis of polyamide microcapsules and effect of critical point drying on physical aspect

“…While drying in air, the specimen is subjected to considerable surface tension to air, which is present at the phase boundary as the water evaporates. Similar phenomena were observed in our polymer nanowire drying process [17]. The SEM images from top view and 45 • angle in figures 5(a) and (b) clearly show that vertically aligned polypyrrole nanowires were clumped together by the surface tension of water after drying in air.…”