Light Sensor Platform Based on the Integration of Bacteriorhodopsin with a Single Electron Transistor

Abstract

This paper reports on the integration of an optical protein with single electron transistors to form a nano-bio-hybrid device for sensing. Bacteriorhodopsin (bR) is an optoelectric protein that translocates a proton across a distance of several nanometers in response to an absorbed photon of incident light. This charge gradient results in a measurable voltage in the dried state. Single electron transistors (SETs) have active regions consisting of one or more quantum islands with a size typically 10 nanometers or less. Integrating bacteriorhodopsin with the gate of a SET provides a device capable of a modulated electrical output in response to optical modulation at the device gate. Modulation of the optoelectric activity of the bR by chemical binding with a targeted environmental antigen can form a direct chemical-to-electrical sensor reducing the size and complexity of fluorescence-based systems. The work resulted in electrical resistance and capacitance characterization of purple membrane containing bR under variable illumination to ensure minimal impact on SET operation. Purple membrane containing bacteriorhodopsin was electrodeposited on the SET gates, and current throughput was well correlated with variable and cyclic illumination. It was confirmed that bR optoelectric activity is capable of driving SETs.

Recent Advances in the Field of Bionanotechnology: An Insight into Optoelectric Bacteriorhodopsin, Quantum Dots, and Noble Metal Nanoclusters

“…Pushing the device sizes even smaller, Walczak [ 32 ] and Walczak et al [ 53 , 54 ] integrated PM onto the gates of multiple quantum dot-based room-temperature single electron transistors (SETs). In this work, the SET devices were fabricated using focused ion beam deposition of 8 nm and larger tungsten quantum dots in the active area between larger electrodes.…”

Ferritin Single-Electron Transistor

“…Also, hybrid biodevices in which proteins have been used in addition to independently fabricated SETs were published as well. 33,34 Previously, the fabrication of single-electron devices using ferritin 35 particles was described by us, 36 in which single ferritin particles were trapped in wide self-aligned nanogaps, displaying Coulomb blockade behavior. However, due to the poor gate coupling of the back gate in those devices, well-resolved threeterminal measurements could not be performed.…”

Engineering and Production of the Light-Driven Proton Pump Bacteriorhodopsin in 2D Crystals for Basic Research and Applied Technologies

“…During a complete photocycle, a proton is transported from the intra- to the extracellular side of the protein, establishing an electric current (photocurrent). This photoelectric effect is applied in photovoltaic devices [ 28 ], optical switches [ 29 ], optical logic gates [ 30 ], light sensors [ 31 ], single electron [ 31 ]- and field effect transistors [ 32 ], chemical sensors [ 33 , 34 ], optical microcavities [ 35 ] and may even lead to protein-based retinal implants [ 36 ].…”