Preparation Of Iron-based Matel-organic Frameworks Nanozyme For Metabolites Detection

As an efficient biocatalyst,natural enzymes involved in almost all metabolic processes that sustain life.Due to the high catalytic activity and substrate specificity of natural enzymes,they are widely used in the fields of environmental protection,food industry and biomedicine.However,because of its protein nature,natural enzymes usually suffer from fatal drawbacks such as the catalytic activity is easily affected by the environment,difficult purification and high cost.These disadvantages have severely hindered the investigation of their functions and also limited their practical applications.To overcome these drawbacks,researchers have long been engaged in the exploration of artificial enzymes.With the fusion of biology and nanotechnology,the research of nanoenzymes has been emerging constantly.To date,various nanomaterials(such as metal nanomaterials,metal oxide nanomaterials,and carbon nanomaterials)with enzymes-mimicking catalytic properties have been reported.Benefitting from their high catalytic activity,good stability and low cost,nanoenzymes have been widely used in various fields.Metal-organic frameworks are a kind of stable porous functional material formed by the coordination of metal central and organic ligands.Since the variable valence metal centers,unsaturated metal coordination and modifiable organic ligands,MOFs are widely used as catalysts especially in the catalysis of redox reactions.More importantly,the framework structures of highly ordered micropores make MOFs with a high specific surface area which provides rich absorption sites and enormous catalytic sites,ensuring the excellent catalytic performance of MOFs,which make MOFs as ideal candidates for nanozymes.In this work,we have constructed a Fe-MOFs nanozyme and Fe-MOFs nanozyme composites,further constructed biosensors for the colorimetric detection of small biological molecules based on the peroxidase-like activity of Fe-MOFs nanozymes.The main research contents are as follows:(1)The Fe-MOFs nanozyme with enzyme-mimicking active sites were constructed by using iron ions as the metal central and porphyrin analogs as the organic ligands.We further combined Fe-MOFs with other functional nanomaterials to synthesize Fe-MOFs composites,Fe-MOFs@UCNP and Fe-MOFs@PLNP.A series of characterizations were performed for the as-developed Fe-MOFs and Fe-MOFs composites.The experimental results show that Fe-MOFs exhibit excellent crystallinity and highly ordered microporous nanostructure,and Fe-MOFs composites have also been successfully synthesized,providing an effective way for the construction of nanozyme and MOFs-based composites.(2)We have explored the peroxidase-like catalytic activity of Fe-MOFs nanozyme.The experimental results show that Fe-MOFs nanozyme exhibit excellent catalytic activity and good stability.Furthermore,based on the excellent activity,a biosensors was constructed for colorimetric detection of H₂O₂.In addition,a biosensor was constructed for glucose colorimetric detection by combining with glucose oxidase.The biosensors display highly selective and selective,providing a simple and effective method for colorimetric detection of H₂O₂ and glucose.