Amino Acid Sensing Using an Ion-Sensitive Field-Effect Transistor

Ion-sensitive field-effect transistor （ISFET）-based biosensor for amino acids was proposed, and the response of the sensor to amino acids was evaluated. As a molecular recognition element, aminoacyl-tRNA synthetase which would be expected to have high selectivity for the corresponding amino acids was used, aminoacyl-tRNA synthetase was coated onto an ISFET electrode, and the response of the biosensor to amino acids was evaluated. The amino acid sensor for tyrosine showed a selective response to tyrosine because of the specific binding ability of aminoacyl-tRNA synthetase for tyrosine and from 300μM to 900 μM of tyrosine could be measured （r2 〉 0.969）.

Low Gate Voltage Operated Multi-emitter-dot H^+ Ion-Sensitive Gated Lateral Bipolar Junction Transistor

A low gate voltage operated multi-emitter-dot gated lateral bipolar junction transistor （BJT） ion sensor is proposed. The proposed device is composed of an arrayed gated lateral BJT, which is driven in the metal-oxidesemiconductor field-effect transistor （MOSFET）-BJT hybrid operation mode. Further, it has multiple emitter dots linked to each other in parallel to improve ionic sensitivity. Using hydrogen ionic solutions as reference solutions, we conduct experiments in which we compare the sensitivity and threshold voltage of the multi-emitter-dot gated lateral BJT with that of the single-emitter-dot gated lateral BJT. The multi-emitter-dot gated lateral BJT not only shows increased sensitivity but, more importantly, the proposed device can be operated under very low gate voltage, whereas the conventional ion-sensitive field-effect transistors cannot. This special characteristic is significant for low power devices and for function devices in which the provision of a gate voltage is difficult.

Bacteriorhodopsin and SWCNT Scaffold for Optical Nanobiosensor

This paper describes theoretical steps to develop an optical nanobiosensor using bacteriorhodopsin （BR） as the biomembrane and Single-Walled Carbon NanoTube （SWCNT） as the scaffold. Bacteriorhodopsin is a retinal protein used by archaea that come under the family of halobacteria. This retinal protein acts as a proton pump and resulting proton gradient is used to change the voltage that pass across the drain and source. The biosensor contains nano ISFET where the channel is made of a carbon nanotube for the conduction of current. The gate is replaced by bacteriorhodopsin biomembrane. Bacteriorhodopsin can be used as a molecular-level ultra fast bi-stable red / green photo switch for making 3D optical molecular memories that reliably store data with 10,000 molecules/bit. The molecules switch in femtoseconds. Biomembrane will sense 510 nm and 650 nm wavelength of light and the sensing voltage can be used to convert the data into digital signals. This molecular level memory device can be used for ‘Read-Write＇ operations. The sensor performance will also be ultra fast since it uses photons for the data storage, which are much faster than electrons used in normal memory devices, and the 3D storage capacity is much higher maximum of 10^13/cm^2.

Sensing with extended gate negative capacitance ferroelectric field-effect transistors

With major signal analytical elements situated away from the measurement environment,extended gate(EG)ion-sensitive fieldeffect transistors(ISFETs)offer prospects for whole chip circuit design and system integration of chemical sensors.In this work,a highly sensitive and power-efficient ISFET was proposed based on a metal-ferroelectric-insulator gate stack with negative capacitance–induced super-steep subthreshold swing and ferroelectric memory function.Along with a remotely connected EG electrode,the architecture facilitates diverse sensing functions for future establishment of smart biochemical sensor platforms.