Heavy metals such as arsenic, chromium, lead, mercury, and cadmium are ubiquitous in the environment, often detectable at concentrations far exceeding those considered safe. Acute and chronic exposure to heavy metals poses severe risk to humans, causing many disorders including central nervous system diseases, kidney and liver diseases, and cancer. The current state-of-the-art in detecting and quantifying heavy metals is based on inductively couple plasma/mass spectrometry and atomic absorption spectrometry. These methods, while able to quantify heavy metals to nanomolar concentrations, require extensive sample preparation and costly, lab-based instrumentation. Analytical methods capable of detecting relevant levels of heavy metals that are more amenable to rapid, field-portable platforms are greatly desirable.  To that end, we have developed a cell-free protein synthesis based biosensing system for the detection of cadmium. The <i>cadA</i> cadmium resistance operon from <i>Staphylococcus aureus</i> contains a transcriptional regulatory protein, CadC, which modulates the expression of cadmium resistance genes from the CadO operator. We have engineered a plasmid in which the expression of sfGFP is regulated by CadC and demonstrated the concentration-dependent expression of sfGFP in a cell-free protein synthesis system. This biosensing system is capable of rapidly detecting micromolar concentrations of cadmium in a format that is readily amenable to portable analytical platforms, as only fluorescence is measured. Additionally, upon substitution of a colorimetric reporter for sfGFP, this type of sensing system is amenable to highly-portable paper-based formats that are well-suited for resource-limited locales.

Rapid cell-free protein synthesis based biosensing system for the detection of cadmium

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.