Construction Of Electrochemical Biosensor Based On Multi-metal Node-based Metal Organic Frameworks Node Mofs

Electrochemical biosensors are valuable analytical technologies,which combines the sensitive analytical performance of electrochemistry analysis with biological technology.Because of possessing the merits,such as high sensitivity of electrochemical detection,short analysis time and high selectivity of bio-specific recognition,electrochemical biosensors have attracted widespread attention in clinical analysis.In order to achieve accurate and ultra-sensitive detection of trace targets,we designed dual-signal readout strategy and multiple-amplified strategy based on the redox-activity,nanozyme activity and electrocatalytic activity of metal-organic framework(MOFs)to achieve accurate and sensitive analysis of cancer markers.The main research contents are as follows:1.Dual-signal readout aptasensor for electrochemical and colorimetric assay using a bifunctional Ni-Fe PBA probe.To promote the accuracy of biosensor,we report a dual-readout,electrochemical and colorimetric aptasensor for accurate assay of disease biomarkers,based on the Ni-Fe prussian blue analogue(Ni-Fe PBA)as a bifunctional signal probe.Specifically,the redox of plural metal ions in Ni-Fe PBA endows it with excellent redox-activity,providing an obviously well-defined redox current for EC detection.Meanwhile,the peroxidase-like activity of Ni-Fe PBA can catalyze the decomposition of H₂O₂ and oxidation of chromogenic substrate(TMB),which is beneficial for colorimetric analysis.Based on the excellent redox-activity and peroxidase-like activity of the bifunctional Ni-Fe PBA,we realized dual-readout EC and colorimetric detection of platelet-derived growth factor BB(PDGF-BB).This single probe(Ni-Fe PBA)acting as bifunctional roles depends on two different mechanisms and relatively independent signal transduction,which avoids fussy assembly of diverse probes and decreases the uncontrollable factor in different batches.As a result,an EC-colorimetric dual-readout aptasensor shows two linear responses in the range of 0.0001-5 n M and 0.01-50 n M for PDGF-BB,providing more accurate and reliable results compared with the traditional single-signal readout method.2.Trimetal node-based metal-organic frameworks and protein-scaffolded DNA nanostructure as dual signal amplifiers for ultrasensitive biosensing of miRNA-21.To promote the sensitivity of biosensor,an effective multiple-amplified strategy based on protein-scaffolded DNA nanostructure as nanocontainer and trimetal node MOF as electrocatalyst is presented to establish electrochemical assay for ultrasensitive sensing of miRNA-21.Specifically,the protein-scaffolded DNA nanostructure is seeded from protein as the model scaffold,which is beneficial for biotin-labeled DNA rapid and facile assembly to be dendritic DNA nanostructure with a large loading capacity for signal molecules(Thi).And through simultaneous incorporating Ni,Co and Fe metal nodes into one MOF-74 cluster,the resultant NiCoFe MOF-74 is endowed with desirable electrochemical performance toward Thi.As expected,the constructed electrochemical biosensor possesses a detection limit down to 0.3 f M for measuring miRNA-21 and exhibits an excellent analytical performance to real samples of miRNA-21 both in the human cancer cells and human serum samples.