title: Yeast dual-affinity biobricks: Progress towards renewable whole-cell biosensors.
abstract: Point-of-care (POC) diagnostic biosensors offer a promising solution to improve healthcare, not only in developed parts of the world, but also in resource limited areas that lack adequate medical infrastructure and trained technicians. However, in remote and resource limited settings, cost and storage of traditional POC immunoassays often limit actual deployment. Synthetically engineered biological components ("BioBricks") provide an avenue to reduce costs and simplify assay procedures. In this article, the design and development of an ultra-low cost, whole-cell "renewable" capture reagent for use in POC diagnostic applications is described. Yeast cells were genetically modified to display both single chain variable fragment (scFv) antibodies and gold-binding peptide (GBP) on their surfaces for simple one step enrichment and surface functionalization. Electrochemical impedance spectroscopy (EIS) and fluorescent imaging were used to verify and characterize the binding of cells to gold electrodes. A complete electrochemical detection assay was then performed on screen-printed electrodes fixed with yeast displaying scFv directed to Salmonella outer membrane protein D (OmpD). Electrochemical assays were optimized and cross-validated with established fluorescence techniques. Nanomolar detection limits were observed for both formats.
authors: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
authors: A G
authors: AG
authors: Venkatesh
authors: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
authors: Alexander
authors: A
authors: Sun
authors: School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
authors: Howard
authors: H
authors: Brickner
authors: VA San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA; School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
authors: David
authors: D
authors: Looney
authors: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA.
authors: Drew A
authors: DA
authors: Hall
authors: School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA. Electronic address: earonoffspencer@ucsd.edu.
authors: Eliah
authors: E
authors: Aronoff-Spencer
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis* / Q000276:immunology; D001681:Biological Assay / Q000295:instrumentation; D015374:Biosensing Techniques / Q000295:instrumentation*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D059027:Recycling; D015203:Reproducibility of Results; D012475:Salmonella / Q000276:immunology / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D020798:Two-Hybrid System Techniques / Q000295:instrumentation*
chemical_list: D000942:Antigens, Bacterial
keywords: Electrochemical ELISA; Electrochemical Impedance Spectroscopy; Gold binding peptides; Point-of-care diagnostics; Single chain variable fragment antibody; Yeast surface display