Development of Modular, Tunable Biosensors for Amyloid Beta and CTLA-4 — 41p — Min Kyung Park, Megan Finstrom, Dr. Yun-Seok Choi

Genetically encoded biosensors allow for the study of cellular processes and  biomarker detection, offering spatiotemporal and quantitative information regarding target  proteins. Existing biosensor designs suffer from multiple problems, such as low signal  dynamic range and the need for the sensor to undergo a large structural change after binding.  Here we display a modular biosensor design which uses Anticalin® as the target binding  domain and various reporter domains (e.g., NanoBiT and ChemoX), allowing for quantification of target proteins. Anticalin is a small version of antibodies derived from  human lipocalin, NanoBiT is a split luciferase, and ChemoX is a recently developed FRET  pair with high signal dynamic range. Specifically, we designed Anticalin-NanoBiT sensors  with high affinity for human peptide amyloid beta 40 (Aβ-40, a biomarker for  neurodegenerative disease) and for cytotoxic T-lymphocyte associated protein 4 (CTLA-4, a  biomarker for cancer). The binding affinities of Aβ-40 Anticalin-NanoBiT and CTLA-4  Anticalin-NanoBiT were confirmed with a binding assay, yielding dissociation constant (Kd)  values of 14.0 nM and 1.47 μM, respectively. The next steps for this research project include  developing Anticalin-ChemoX sensors for application in cells and applying Anticalin NanoBiT to bodily fluids to detect levels of amyloid beta.

Black Hills State University
Dr. Yun-Seok Choi