Detection of inorganic ions and organic molecules with cell-free biosensing systems

Efforts to use genetically modified cells to detect inorganic ions and organic molecules have been hindered by biosafety concerns, limitation of cell membrane barriers, cytotoxicity problems, and unfriendly operations. To address those challenges, cell-free biosensing systems were established to detect arsenic, mercury, acyl-homoserine lactone, and benzoic acid in this study. The cell-free system mimics biological transcription and translation activities in an open environment without living cells. The most bioactive cell-free system was obtained by screening different Escherichia coli strain extracts and Mg²⁺ concentrations. It was found that the sensitivity of cell-free systems could reach nanomolar levels with the short response time. The selectivity experiments showed that cell-free biosensing of inorganic ions had no signal interference. Cell-free biosensing systems, with their wide range of molecule detection, short response time and high specificity, could potentially serve as powerful biosensing platforms for environmental and medical applications.