Development of a nanozyme-based electrochemical sensor for detection of stringent response.

PpGpp (Guanosine 3',5'-bisdiphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate) are important biological compounds in stringent response of organisms and play a crucial role in their growth and survival. At present, there is no report on the method for comprehensively detection of stringent response. In this study, a nanozyme-based electrochemical sensor was fabricated by self-assembly and was used for detecting stringent response with high sensitivity (Km of ppGpp is 1.498 × 10 mol/L and Km of NADPH is 7.489 × 10 mol/L) and selectivity. The sensor exhibited advantages of fast response times (∼50 s), high specificity, and simple operation. The sensor was successfully used to detect stringent response in Arabidopsis thaliana leaf extracts, Escherichia coli extracts and serum samples from SD rats. Notably, the method does not require complex sample pretreatment and has high application potential for comprehensively detecting overall nutritional status that is involved in the stringent responses of animals, plants, and microorganisms.