Rapid,Sensitive And Highly Selective Detection Of Biomolecules Based On Silicate Materials For Applications

Natural enzymes play a vital role in the physiological activities of living organisms as molecules with high catalytic activity and outstanding selectivity,but there are inherent defects that cannot be avoided in protein-based natural enzymes.Under harsh physical or chemical conditions of use,the activity of natural enzymes is limited or even completely inactivated,severely limiting their application in industrial production,biomedicine and environmental management.In recent years,nanomaterials have been found to have enzyme-like catalytic properties（nanoenzymes）that can maintain their catalytic activity under harsh conditions of use,making them an ideal alternative to natural enzymes.Manganese-based materials have been extensively investigated in industrial,medical,and biological fields,owing to their vivid imaging,good biocompatibility and simple synthesis process.The catalytic activity of nanoenzymes can be tuned by surface engineering and structural modulation to meet the needs of different applications,leading to rapid development in areas such as antibacterial therapy,tumour therapy and biosensing.However,nanoenzymes still suffer from low substrate affinity,which significantly reduces the catalytic kinetics of nanoenzymes and thus affects the sensitivity and stability of biomolecule detection.In this paper,two amorphous metal-based nanomaterials with different structures were prepared,their catalytic kinetics were investigated,the mechanism influencing the catalytic activity was revealed,and highly sensitive and reliable detection of biological thiols was achieved.The main studies are as follows:Ⅰ.Manganese silicate hollow sphere oxidase for the colourimetric detection of biodithiols.A one-step synthesis of manganese silicate nanospheres with hollow structures was carried out by a simple hydrothermal method to achieve ultra-sensitive and highly reliable detection of biodithiols.The amorphous hollow structure has the ability to rapidly release high-valent Mnx+and dissolved oxygen can assist in enhancing the catalytic oxidation of the substrate,achieving a high affinity for the substrate and significantly improving the sensitivity of the assay.The AHMS-based colorimetric detection strategy was shown to have excellent catalytic kinetics and very low detection limits(K_m=27.1μM,LOD_GSH=20 n M).Furthermore,in the complex environment of biofluids（fetal bovine serum,Staphylococcus aureus）,the manganese silicate nanosphere based oxidase exhibited highly sensitive,highly selective detection.Ⅱ.Amorphous manganese silicate oxidase for ultra-sensitive and highly reliable biological thiol detection.Amorphous manganese silicate was successfully synthesised by co-precipitation method and was used as an oxidase mimetic with ultra-sensitivity and high reliability.DFT calculations demonstrated that manganese silicate was able to release Si O₃^2-ions to interact with the substrate,significantly improving the stability of the oxidised substrate ox TMB and obtaining a stable detection curve plateau（～10 min）,and samples tested at any point in time on the detection plateau exhibited a high degree of reliable accuracy,which can eliminate interference due to individual operating time differences.In addition,further colourimetric detection based on amorphous manganese silicate for specific analysis of biological fluids（fetal bovine serum and cancer cells）and the design of visual logic gates provide a promising solution for the implementation of ultra-sensitive and highly reliable biosensing in electronic components.