Near-infrared Fluorescent Aptamer Sensor for ATP Based on CuInS2@ZnS Quantum Dots

Abstract:

Detecting the level of adenosine triphosphate (ATP) in plants is of significant importance for evaluating plant growth and metabolism, monitoring plants’responses to environmental stresses, conducting research on plant pathology and physiological processes, as well as guiding agricultural production practices. A near-infrared fluorescent sensor for the sensitive detection of ATP was developed based on CuInS2@ZnS quantum dots (QDs). The CuInS2@ZnS QDs were prepared by using the hot decomposition method. Negatively charged MPA-modified CuInS2@ZnS QDs were able to interact with positively charged carboxymethyl chitosan, resulting in the formation of carboxymethyl chitosan-coated CHIT/CuInS2@ZnS nanocomposites. The aptamer of ATP, possessing a strong negative charge, induced aggregation of the positively charged nanocomposites through electrostatic and hydrogen bonding interactions, leading to fluorescence quenching. The sensor exhibited a linear relationship between the fluorescence intensity (I/I0) of the CHIT/CuInS2@ZnS nanocomposites and the logarithm of ATP concentration within the range of 5pmol/L to 10nmol/L. The detection limit of the sensor was determined to be 1.67 pmol/L. The research successfully established a CuInS2@ZnS quantum dot-based near-infrared fluorescent sensor for sensitively detecting ATP. This sensor has important theoretical significance and practical value for the growth and development of plants and the judgment of their stress responses to the external environment.