Light-Addressable Potentiometric Sensors Using ZnO Nanorods as the Sensor Substrate for Bioanalytical Applications

• Main Authors: Ahmad, N. (Author), Briscoe, J. (Author), Krause, S. (Author), Tu, Y. (Author), Zhang, D.-W (Author)
• Format: Article
• Language: English
• Published: American Chemical Society 2018
• Subjects: alpha-chymotrypsin; Amides; animal; Animals; Bioanalytical applications; Biosensing Techniques; bovine; Cattle; Cell signaling; Chemical analysis; chemistry; chymotrypsin; Chymotrypsin; Commercial applications; devices; Electrical potential; Electrolyte insulator semiconductors; Electrolytes; equipment design; Equipment Design; genetic procedures; II-VI semiconductors; Image enhancement; Image resolution; laser; Lasers; light; Light; Light addressable potentiometric sensors; Magnetic semiconductors; metabolism; Microfluidic channel; Nanorods; nanotube; Nanotubes; Photocurrents; polyester; Polyesters; Potentiometers (electric measuring instruments); Potentiometric sensors; potentiometry; Potentiometry; Semiconducting zinc compounds; semiconductor; Semiconductor structure; Semiconductors; Spatiotemporal images; Substrates; ultrastructure; Wide band gap semiconductors; zinc oxide; Zinc oxide; Zinc Oxide
• Online Access: View Fulltext in Publisher; View in Scopus

 Light-addressable potentiometric sensors (LAPS) are of great interest in bioimaging applications such as the monitoring of concentrations in microfluidic channels or the investigation of metabolic and signaling events in living cells. By measuring the photocurrents at electrolyte-insulator-semiconductor (EIS) and electrolyte-semiconductor structures, LAPS can produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. However, its commercial applications are often restricted by their limited AC photocurrents and resolution of LAPS images. Herein, for the first time, the use of 1D semiconducting oxides in the form of ZnO nanorods for LAPS imaging is explored to solve this issue. A significantly increased AC photocurrent with enhanced image resolution has been achieved based on ZnO nanorods, with a photocurrent of 45.7 ± 0.1 nA at a light intensity of 0.05 mW, a lateral resolution as low as 3.0 μm as demonstrated by images of a PMMA dot on ZnO nanorods and a pH sensitivity of 53 mV/pH. The suitability of the device for bioanalysis and bioimaging was demonstrated by monitoring the degradation of a thin poly(ester amide) film with the enzyme α-chymotrypsin using LAPS. This simple and robust route to fabricate LAPS substrates with excellent performance would provide tremendous opportunities for bioimaging. © 2018 American Chemical Society.