Membrane receptor-based high molecular density bioelectronic platform

In collaboration with Prof. Uwe Sleytr and Dr. Andreas Breitwieser (BOKU, Vienna, Austria).

Bioelectronics is an emerging antidisciplinary field which utilizes biomolecules in electronics, mimics biological architectures, or builds electronic-living organism interfaces. One important aspect of the field is to fabricate sensors for label-free biomolecules detection. Researchers previously designed sensors based on i) metal-oxide-semiconductor (MOSFET), ii) polymers, and iii) inorganic crystalline materials which produce good sensitivity, but lack selectivity. Recent efforts are devoted to directly connecting biological receptors with electronic systems. G protein-coupled receptors (GPCRs) serve as suitable candidates as they are the largest family of membrane receptors that detect information (molecules and lights) and transduce to cell internal signals to regulate body functions. 

There are ~1,000 GPCR proteins in human cells, each one highly specific to a particular signal. QTY-designed, detergent-free GPCR receptors can be modified and attached to recombinant-SbpA proteins, which are capable of reproducing two-dimensional crystalline monolayers on various electronic surfaces, as demonstrated by Prof. Uwe Sleytr in Vienna, Austria. SbpA 2D crystalline guides the orientation of the attached GPCRQTY receptors and exposes their active binding sites. The self-assembly yields functional molecules with high density >10^12 molecule/cm^2. The bioelectronics platform yields detectable electrical, electrochemical, or optical signals in response to the biological stimuli from the receptor layer. When coupled with different types of receptors, this approach may be a platform for bioelectronics and ultrasensitive-sensing systems.

Qing, R. et al. (2020) To be published.

Figure caption: The S-layer protein coupled with water-soluble GPCRs can be designed as an extremely high-density sensing device. The tetramer S-layer proteins form 2D crystalline about 13 square nm and each have two receptors with the ligand binding site upward, so a total eight receptors on the 13 square nm area. That is for an area of one square cm; it has a density >1 trillion receptors with recognition and binding capability.