Construction Of Nitrogen-Doped Multicavity Mesoporous Carbon Nanoparticles And Their Preliminary Drug Loading Properties

Mesoporous carbon nanoparticles(MCNs)have played an irreplaceable role in catalysis,energy storage conversion,adsorption separation,drug storage and release,and other fields due to their large specific surface area,large pore volume,and unique structural characteristics.In fact,the performance of MCNs would be unquestionably affected by their structural and morphological characteristics,such as internal hollow chambers,thickness in the shell,pore size distribution,particle surface roughness and so on.Accordingly,the preparation of MCNs with specific particle morphological configuration has always been one of the hot issues in carbon nanomaterials research.In recent years,MCNs with internal multicavity structure had attracted the attention of researchers,but preparation process had been facing the following problems: The merging of emulsion droplets in emulsion methods.In the process of preparing multicavity mesoporous carbon nanoparticles(MMCNs),small droplets coalesced into large emulsion droplets,which often led to the formation of single-cavity(hollow)MCNs;The complicated experimental process.The preparation of multicavity structures often requires silicon layer coating and selective etching of silicon layer to provide a limited pyrolysis region,so that the internal single cavity will split into a multicavity structure due to the change of gas pressure inside the particles under high temperature carbonization.In the process of preparing MMCNs by restricted pyrolysis,silicon layer coating and selective etching were required to provide a restricted pyrolysis region,which causes the single cavity inside the particle to split into multicavity structure,which undoubtedly greatly increases the complexity of experimental steps.Based on the above analysis,the internal construction process of MMCNs was deeply studied in this paper.The Res--NMMCNs drug-loading system was successfully constructed using the prepared the prepared nitrogen-doped multicavity mesoporous carbon nanoparticles(NMMCNs)as drug carrier and resveratrol(Res)as model drug,and its drug release properties was further investigated.The main research contents are as follows:(1)Innovatively,this research designed an emulsion-induced selfassembly method to prepare NMMCNs with a Cherimoya-shaped rough surface under acid curing conditions.Moreover,the "emulsion swelling—acid curing mechanism" was also proposed to explain its growth mechanism.a series of NMMCNs with Cherimoya-shaped rough surface and adjustable internal cavity were obtained via employing amphiphilic surfactant F127 as a template,3-AP and formaldehyde as carbon sources,and DEP as a swelling agent under EDA alkaline conditions.In this method,the problem of uneven particle size of emulsion droplets is avoided through the process of preparing secondary emulsion under high-speed shearing force and rapid cooling.Next,this method does not involve complicated silicon layer coating process,and the experimental process is simple.Furthermore,the introduction of the acid curing procedure enhanced the degree of cross-linking between the colloidal polymers,which further enhanced the stability between the secondary structural units of the polymers.Scanning electron microscopy and transmission electron microscopy images showed that the morphology of the multi-cavity mesoporous carbon nanoparticles remained intact after the high-temperature carbonization process under the acid curing procedure.(2)Using the prepared NMMCNs as the drug carrier and Res as the drug model,the resveratrol bulk drug was analyzed by UV spectrophotometry,and the precision,recovery rate and stability of the method were investigated.The optimal drug loading ratio between the drug and the material was determined by X-ray diffraction,FTIR spectroscopy and differential scanning calorimetry analysis.Moreover,the Res--NMMCNs drug-loading system was also successfully constructed.The above results showed that the precision,recovery,and stability of resveratrol met the requirements,and Res--NMMCNs had good drug loading capacity.(3)Cytotoxicity and hemolysis experiments showed that NMMCNs have the advantages of low cytotoxicity and low hemolysis rate,exhibiting good biocompatibility,which can be further applied as a drug delivery system.Meanwhile,the cellular uptake experiments showed that NMMCNs could well enter cells by endocytosis and be taken up by living cells.Surprisingly,In the drug release experiments in vitro with different p H buffers as release media,the drug release amount of Res--NMMCNs-2 was higher than that of pure Res,which well proved that the NMMCN material can be used as a drug carrier for insoluble drug Res.The fitting results of the drug dissolution experimental data showed that the drug release curve of Res--NMMCNs-2 was more in line with the Weibull release model,indicating that the release of Res had gone through two processes: the rapidrelease stage,and the slow-release stage.Since the natural drug Res has antioxidant and antitumor activity,antioxidant and antitumor activity experiments in vitro showed that the Res--NMMCNs drug-loading system can improve the antitumor and antioxidant activity of Res in vitro.