Aptamer-Embedded Zirconium-Based Metal–Organic Framework Composites Prepared by De Novo Bio-Inspired Approach with Enhanced Biosensing for Detecting Trace Analytes

A series of Zr-based metal-organic framework (MOF) composites embedded with three kinds of aptamer strands (509-MOF@Apt) were achieved by a one-step de novo synthetic approach. A platform for ultrasensitive detection of analytes, namely, thrombin, kanamycin, and carcinoembryonic antigen (CEA), was also established. Considering the conformational changes caused by the binding interactions between aptamer strands and targeted molecules, the label-free electrochemical aptasensors based on 509-MOF@Apt composites could be developed to detect various target molecules. By comparing the common fabrication approaches of aptasensors, a distinct determination mechanism was presented through analysis of the electrochemical measurements on different interaction behaviors between probe aptamer strands and 509-MOF materials. The optimized aptasensors based on 509-MOFs@Apt demonstrated excellent sensitivity (with the detection limit of 0.40, 0.37, and 0.21 pg mL-1 for CEA, thrombin, and kanamycin, respectively), stability, repeatability, and applicability. This work will provide a new platform for direct and feasible detection in biosensing related to clinical diagnostics and therapeutics, and further, extend the scope of potential applications for MOF materials.