Genetic Circuits to Detect Nanomaterial Triggered Toxicity through Engineered Heat Shock Response Mechanism

Abstract

Biocompatibility assessment of nanomaterials has been of great interest due to their potential toxicity. However, conventional biocompatibility tests are short of providing a fast toxicity report. We developed a whole cell based biosensor to track biocompatibility of nanomaterials with the aim of providing fast feedback for engineering nanomaterials with lower toxicity levels. We have engineered promoters of four heat shock response proteins. As an initial design a reporter coding gene was cloned to downstream of the promoter regions selected. Initial results indicated that native HSP promoter regions were not very promising to generate signals with low background signals. Introducing riboregulators to native promoters eliminated unwanted background signal almost entirely. Unfortunately, this approach also leads a decrease in expected sensor signal. Thus, a repression based genetic circuit, inspired from HSP mechanism of Mycobacterium tuberculosis was constructed. These genetic circuits can report the toxicity of Quantum Dot nanoparticles in one hour with high precision. Our designed nanoparticle toxicity sensors can provide quick reports which can lower the demand for additional experiments with more complex organisms.