Preparation Of N-doped Mesoporous Carbon Nanoparticles With Multiple Morphologies And Their Preliminary Study As Drug Carriers

Mesoporous carbon nanoparticles(MCNs)integrate with the advantages of mesoporous material and nanoparticles owing to their meso-structured channels and nanoscale particle size.Their high specific surface area,large pore capacity,excellent mechanical stability,open-framework structures and good biocompatibility make MCNs attract close attention of professionals in many fields,such as energy storage and conversion,drug delivery and release,chemical catalysis,adsorption.At present,the common methods for fabricating MCNs include hard-templating route,self-assembly and hydrothermal process,among which,one-step aqueous solution self-assembly procedure has been widely concerned and developed rapidly due to its advantages of less steps,simple operation and mild reaction conditions.However,the one-step aqueous solution self-assembly method also exists in many limitations.On the one hand,it is difficult to realize the fabrication of MCNs with small particle size less than 200 nm by using this method to date,and it is also rarely reported to employ this method to synthesize MCNs with asymmetric structure.Therefore,a simple and efficient synthesis scheme is urgently needed to produce asymmetric MCNs with novel morphology and small particle size.On the other hand,the acidic or alkaline reagents have been commonly involved in this synthetic way to enhance the interaction between organic carbon precursor and soft template,due to the weak interaction may cause the difficulty of assembly process between them.It is known that the acid and alkali are corrosive,and the waste liquid produced in the synthesis process will have a certain negative impact on the environment.Therefore,a greener and more environmentally-friendly strategy is urgently needed to synthesize MCNs.This article has carried on the thorough and concrete research to the above question.For the first time,a novel dual soft-templated congenerous assembly method was demonstrated to synthesize the raspberry-shaped N-doped mesoporous carbon nanoparticles(NMCNs)in one-pot aqueous solution with large mesopore size and small particle size.In addition,a salt-catalyzed one-step aqueous solution self-assembly was firstly proposed to prepare nitrogen-containing ordered mesoporous carbon nanospheres(N-OMCNs).In this process,the acid or alkali was replaced by sodium chloride as catalyst,and there was no organic solvent such as ethanol,which possessed it with green and friendly-environmental benefit.Moreover,the above two synthetic strategies used 3-aminophenol and hexamine(HMT)as carbon precursor,wherein 3-aminophenol could also be used as nitrogen source to introduce nitrogen atom directly,avoiding the problem that employing the additional N-containing reagent as nitrogen source might lead to the failure of the introduction of nitrogen atom or low nitrogen content.Meanwhile,the introduction of nitrogen atoms into mesoporous carbon nanoparticles grains to functionalize them,which can improve their hydrophilicity,chemical activity and so on,thus broadening their application range.The main contents of this paper are as follows:(1)Raspberry-like NMCNs were firstly synthesized via one-step aqueous solution self-assembly method under strong acid conditions,wherein formaldehyde released by the hydrolysis of HMT reacted with 3-aminophenol to form 3-aminophenol/formaldehyde(APF)resin,and it acted as N-containing carbon source,F127 and sodium oleate(SO)as dual soft templates,ethanol and water as solvents.The study found that by adjusting the amount of F127,the morphology of NMCNs could be transformed from raspberry-like to intact spherical.In addition,tuning the amount of SO,ethanol and hydrochloric acid could control the morphology and structure of raspberry-like NMCNs.Through cytotoxicity experiment and cellular uptake essay,it was proved that raspberry-like NMCNs had good biocompatibility and were easily ingested by living cells.Furthermore,the obtained raspberry-like NMCNs as drug carriers significantly improved the dissolution and release performance of carbamazepine.(2)N-OMCNs were synthesized by using sodium chloride as catalyst,3-aminophenol and hexamine as carbon source,F127 as template.The innovation lied in the use of sodium chloride instead of acid or alkali as catalyst,and no organic solvent added.The synthesis steps were simple and green.By adjusting the amount of sodium chloride,the force between the F127/APF resin composite micelle unit cells could be enhanced,thus abtaining a good ordered mesoporous structure.Moreover,the particle size of N-OMCNs could be changed by adjusting the amount of sodium chloride and F127.Acid red dye was selected as the model for adsorption experiment,and the results showed that N-OMCNs had excellent adsorption property.