Preparation And Properties Of New Carbon Dots Loaded Large Pore Mesoporous Organosilica Drug Nanocarriers

Background: Multifunctional gene/drug nanocarriers are the key and hotspot for the visualization of molecular functions in the integration of tumor diagnosis and treatment.Although after years of hard work,the research in this field has made great progress,but the design and synthesis of nanocarriers with suitable structures is still a huge challenge in clinical medical applications.In recent years,mesoporous organosilica nanoparticles(MONs)have broken through traditional materials in vivo due to their excellent chemical modification,gene carrying capacity,stable transport in the body,environmentally responsive drug release,high intracellular transfection rate and biological safety.The bottleneck of the application in the treatment field shows the broad prospects of clinical application of gene diagnosis and treatment.As a new type of carbon-based fluorescent nanomaterials,carbon dots have attracted widespread attention due to their excellent properties.Carbon dots not only have fluorescent properties comparable to traditional quantum dots,but also are easy to produce,have good water solubility,and have good chemical stability.And biocompatibility,low cytotoxicity.Among them,the carbon dots with deep red fluorescence with a wavelength greater than 660 nm are more conducive to deep tissue imaging.Purpose: The purpose of this study is to synthesize new carbon dots loaded large pore mesoporous organosilica nanocarriers,so that the nanocarrier has large mesopores,which can be used for the encapsulation of therapeutic agents.it has a deep red fluorescence with a wavelength greater than 660 nm,which can be used for deep biological biology.Tissue imaging can achieve its visibility.it is biodegradable and has good biocompatibility and biosafety.Make the newly synthesized nanocarrier an effective delivery vehicle for tumor imaging and precise treatment.Method: We use Tetraethyl orthosilicate and bis[3-(triethoxysilyl)propyl] tetrasulfide as raw materials,and use the precursor co-template assembly strategy to synthesize large pore mesoporous organosilica nanoparticles.In the process,carbon dots with deep red fluorescence are combined with macroporous organic silicon nanoparticles to produce a new type of fluorescent nanoparticles with excellent properties: Large mesoporous and deep red fluorescence,and can be degraded,has good biocompatibility and biosafety.Then the new nanoparticles were connected to PEI.In this study,PEI was connected in two ways: covalent bond connection and charge connection,and the two schemes were compared and the optimal connection method was selected.Results: The test results show that a new type of nanoparticle has been synthesized in this study: large pore mesoporous organosilica nanoparticles.The particle size is uniform,about 40-60 nm,with good dispersibility,large mesopores,up to 7-12 nm.There is a strong deep red fluorescence at a wavelength of 670 nm,and the particles can be degraded under high concentration of glutathione.Through a series of tests,it can be seen that PEI has been successfully coated.The fluorescence intensity of the nanocarrier obtained after the charge is connected to the PEI is stronger and the charge connection is better.Conclusion: Successfully prepared carbon dots loaded large pore mesoporous organosilica nanoparticles(CD@MONs).The particles have good dispersibility,uniform size,large pores,strong deep red fluorescence at a wavelength of 670 nm,can be used for deep tissue imaging,and are degradable,have good biocompatibility and biological safety,and are therapeutic agents carrying and transportation,tracing and imaging are possible.The carbon dots loaded large pore mesoporous organosilica nanoparticles(CD@MONs)are successfully connected to PEI,and the charge connection is better,which can provide a new type of nano-carrier material for the accurate diagnosis and treatment of tumors.