Single Conducting Polymer Nanowire Chemiresistive Label-Free Immunosensor for Cancer Biomarker

Abstract

A simple and cost-effective, all-electrochemical method to fabricate and assemble single conducting polymer nanowire based biosensors was developed. Polypyrrole (Ppy) nanowires were synthesized by electrochemical polymerization using an alumina template. The single-nanowire chemoresistive sensor device was assembled using ac dielectrophoretic alignment followed by maskless anchoring on a pair of gold electrodes separated by 3 microm. To establish an efficient covalent surface biofunctionalization route, glutaraldehyde (GA) and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) chemistries were compared. EDC was established to be the most effective chemistry and was used to surface-functionalize a single Ppy nanowire with cancer antigen (CA 125) antibody to fabricate a nanoimmunosensor for CA 125 biomarker detection and quantification. The immunosensor had excellent sensitivity with a lower detection limit of 1 U/mL CA 125 and dynamic range up to 1000 U/mL in 10 mM phosphate buffer. Furthermore, there was no loss of performance upon exposure to CA 125 in spiked human blood plasma. This demonstrates the clinical importance of these sensors for cancer marker detection with cost benefits and great portability for diagnosis of patients at the point of care.

Microfluidic Electrochemical Detection Techniques of Cancer Biomarkers

“…The "largescale integrated microfluidic chip" was published in the Science journal which described the integrated Fig. 1 Construction of a cancer marker sensor element contained in microfluidics [15]. valves and hundreds of reactor chip, showed a simple electrophoresis large-scale multi-functional integrated laboratory in the chip [25].…”

“…Sato developed a micro quartz weir structure, the adsorbed immunoglobulin A (s-IgA) chip fill with polystyrene microbeads, microbeads entrapped in micro weir at the glue binding gold flowing s-IgA reaction channels with beads [15,16]. They also used this chip and beads to develope a sandwich immunoassay method (Fig.…”

Progress in Research of Flexible MEMS Microelectrodes for Neural Interface

“…Meanwhile, conducting polymers with good biocompatibility is widely applied in biomedical area such as biomedical imaging [45], biosensor [46,47], artificial muscle [48], drug release controller [49], cancer biomarker [50] and neural interface [51,52]. One of the most important roles conducting polymer plays is in the electrode-tissue interface material for neural engineering, as it can be facilely fabricated into multiple structures [53], modified by different doping [54,55] and regulated to undertake electrical stimulation [56,57].…”

Detection of Cancer Biomarkers With Nanotechnology

“…A cost-effective method to fabricate and assemble single conducting Polypyrrole Nanowire (PPy-NW)-based biosensors for CA 125 detection was developed (Bangar et al, 2009). PPy-NWs were aligned across a pair of gold electrodes separated by a gap of 3 µm.…”