The Synthesis And Properties Research Of Manganese Dioxide Microspheres Nucleic Acid Sensing Platforms And Degradable Mesoporous Silica Dioxide Drug Carriers

With the continuous development of materials science,various functional materials with superior properties have been widely applied in biological related fields.For example,as nucleic acid sensing platform,manganese dioxide has a fast and accurate detection advantage,provided new strategy for nucleic acid detection.As drug delivery carrier with intelligent and targeted drug delivery advantages,silica dioxide has considerable development potential in the field of biomedicine.Although the two functional materials got increasing progress in biological applications,but there is still some defects such as manganese dioxide as nucleic acid sensing platform is still low sensitivity,and silica dioxide as drug delivery carrier is still poor degradability.In view of this,manganese dioxide microspheres and degradable mesoporous silica dioxide nanoparticles have been synthesized for nucleic acid sensing and anticancer drug delivery in this paper,aiming to further improve their biological application capacities.Currently,the research works of manganese dioxide as sensing platform is based on manganese dioxide nanosheets.Considering that the larger surface area of manganese dioxide microspheres may have better sensing properties,we have synthesized manganese dioxide microspheres and manganese dioxide nanosheets and compared their sensing performances.It is proved that manganese dioxide microspheres showed stronger fluorescence quenching ability than manganese dioxide nanosheets,thus possess more sensitive nucleic acid sensing properties.In addition,through testing the influences of different chain length probes and different number of base mismatch plasmids in sensing performances,we revealed that the probe possessing completely complementary sequences with target plasmid has the best detection sensitivity and specificity,provided reference for choosing the optimal chain length probe.In addition to its excellent performance in sensing,spherical materials are also widely studied as drug carriers.Given the most silica drug carriers lack of degradability,easy accumulation in organism and causing biological toxicity,we synthesized a disulfide-bond containing mesoporous silica nanoparticle as drug carrier,which can be reduced and degraded in high concentration of glutathione（GSH）in tumor.Under the simulated condition,the synthesized drug delivery carrier presented good degradability and GSH/pH dual response drug release capacity.Through cellular experimental research,we also proved that the drug carrier has good biocompatibility and folic acid targeting drug release effect,revealing the promising potentiality in biomedical application.The degradability of above-mentioned drug carrier requires the involvement of GSH with strong reduction ability.GSH is highly related to many diseases,thus many fluorescent probes that monitor GSH concentration are developed.In addition to GSH,another sulphur-containing reducing molecule hydrogen sulfide（H₂S）is widely exist in organism and is closely related to many diseases and physiological processes,thus developing specific monitoring tools of H₂S content is of vital importance.In view of this,we synthesized a fluorescent probe capable of detecting H₂S.The fluorescent probe has a low detection limit of5.6×10^-8 M in the concentration range of 0-40μM,and when this probe is used for detecting H₂S in real red wine samples,it can be comparable with typical iodine titration method.When prepared into test paper strip for H₂S detection,the fluorescent probe showed good detection effect,so it has practical application potential.