A Portable Cell-Free Biosensor for Detection of Plastic Associated Chemical Signals in Food HTGAA Final Project | In Silico Design | 2026
Tools: Benchling (construct design) · COPASI (kinetic modeling) System: Cell-free BL21 DE3 lysate · Reporter: lacZ (chromogenic)
Section 1: Abstract Bisphenol A (BPA) is a ubiquitous endocrine-disrupting chemical leached from plastics into food, water, and biological systems, with documented links to hormonal dysregulation, metabolic disorders, and developmental toxicity. Despite its pervasive environmental presence, accessible and sensitive field-deployable detection remains limited. This project proposes an in silico design pipeline for a synthetic genetic biosensor that exploits the BPA-responsive transcriptional repressor BmoR to drive chromogenic lacZ expression in a cell-free BL21 DE3 lysate system. The central hypothesis is that a precisely engineered derepression circuit — in which BmoR constitutively silences the Pbmo promoter and BPA-induced conformational change releases this repression — will generate a visible, dose-proportional blue colorimetric signal. Aim 1 establishes the core genetic circuit by designing and annotating a pTXTL-P70a plasmid construct in Benchling and modeling BPA-dependent LacZ protein accumulation kinetics in COPASI across three simulation modes: dose-response, time-course, and detection threshold. Aim 2 focuses on biosensor optimization through parameter sensitivity analysis and encapsulation modeling. Aim 3 envisions translation into a portable, strip-based environmental diagnostic device. Together, this project leverages computational synthetic biology to bridge the gap between genetic circuit design and real-world chemical surveillance, with future implications for decentralized plastic pollution monitoring.
