Fabrication Of Zirconium Metal-organic Frameworks Composites-based Biosensor

In this study,three kinds of zirconium-based metal-organic frameworks including493-MOF,two-dimensional Zr-MOFs and Zr-MOFs embedded with aptamer strands composites（509-MOF@Apt）were synthesized by changing the terminal ligands of each Zr₆cluster,adding polyvinylpyrrolidone,and adding aptamer strands during the preparation process,respectively.Then biosensors were constructed using these materials as sensitive films for detection of target analytes.The performances of the developed biosensors were investigated.This paper mainly includes three aspects:Firstly,by using pore wall functionalization/pore space partition strategy,series Zr-MOFs materials based on the highly stable Zr₆ clusters were obtained with microporous cage and 1-D channels and exhibit good antibacterial activity.The optimized 493-MOF-based biosensor exhibited high sensitivity with a low detection limit of 3.6 pg·m L^-1,selectivity,good repeatability,and good applicability toward detecting lysozyme.This shows that Zr-MOFs can be used in biosensing.Secondly,2D Zr-MOFs（521-MOF）nanosheets with the thickness of 6.5-7.5 nm were prepared with the aid of the surfactant,polyvinyl pyrrolidone,under the mild conditions and low temperature（50°C）.The combination of electrochemical techniques and surface plasmon resonance spectroscopy（SPR）was performed to probe the kinetic processes of the aptamer immobilization and the mucin 1（MUC1）detection.The consistency between different determination approaches was observed,in which the developed aptasensor based on521-MOF nanosheets exhibited pretty high sensitivity for detecting MUC1 with a low detect limit of 0.12 and 0.65 pg·mL^-1 deduced from electrochemical impedance spectroscopyand SPR,respectively.It also demonstrates that this new biosensing strategy shows high selectivity,stability,reproducibility,and good applicability for the MUC1 determination in the human serum.Lastly,a series of Zr-based metal-organic framework（MOFs）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,carcinoembryonic antigen,thrombin,and,kanamycin was also established.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-MOF@Apt demonstrated excellent sensitivity,stability,repeatability,and applicability.This work will provide a new platform for direct and feasible detection in biosensing related to clinical diagnostics and therapeutics.The new platform can explored for different kinds of biosensors and further,extend the scope of potential applications for MOFs materials.