Preparation Of Multi-stimulus Responsive Smart Nano Carrier Based On Cyclodextrin And Their Deliver Anticancer Drugs

In recent years,a series of stimulus responsive smart supramolecular nanoparticles have been developed by researchers,and used them as drug targeted delivery research,which is based on the microenvironment differences between the normal and tumor cells.These smart nano drug delivery carriers have attracted much attention in the field of biomedicine and cancer treatment,because they can realize the targeted delivery and on-demand release of drugs in specific pathological tissues under environmental stimulation,so as to overcome the problems of poor selectivity,poor solubility,low utilization rate and high toxicity of drugs.Cyclodextrins（CDs）as a natural macromolecular oligosaccharide with non-toxic,easy modification,excellent biocompatibility and biodegradability,it is often used as the basic unit for constructing stimulus responsive smart supramolecular nanoparticles.In this work,we have designed and synthesized three β-CD derivatives bearing seven charged located on the upper rim.Then,four stimuli-responsive smart supramolecular nano assemblies were constructed based on β-CD derivative and polysaccharide biomacromolecules,polyethyleneimine and two surfactants,respectively.And their drug loading abilities and drugs release behavior were explored.The specific work contents and related results are summarized as follows:（1）A kind of β-CD derivative bearing seven positively charged was synthesized:per-[6-deoxy-6-（1-methylimidazole）]-β-CD（β-CDIM）.Using negatively charged sodium alginate（SA）and β-CDIM to construct a p H response characteristic β-CDIM/SA smart nanoparticles.The structure,morphology,particle size,surface charge and stability of β-CDIM/SA nanoparticles were investigated by UV-Vis,FT-IR,XRD,SEM,TEM,DLS,AFM and Zeta-potential.The antitumor active molecule CSL was loaded in β-CDIM/SA nanoparticles,the EE % and DLS % were 24.74 % and 16.23 %,respectively.The release curve imaged that the CSL release rate was only 14.5 % in p H=7.4,while the release rate of CSL was as high as 90 % in simulated tumor environment（p H=5.0）.It’s indicated that the β-CDIM/SA nanoparticles possessed p H triggered CSL release switch,which can realize the targeted release of drugs in tumor site.Hemolytic results proved that drug-loaded nanoparticles CSL@β-CDIM/SA had good safety.Interestingly,the cytotoxicity of drug-loaded nanoparticles CSL@β-CDIM/SA to normal cells（BEAS-2B）was greatly reduced,and the cytotoxic activity to SMMC-7721 tumor cells and the induced apoptosis rate of SMMC-7721 were greatly higher than that of free CSL.The β-CDIM/SA nanoparticles provided a new choice and idea for the design and development of novel and convenient targeted anticancer drug delivery system.（2）A kind of β-CD derivative bearing seven negatively charged was synthesized:per-[6-deoxy-6-（3-mercaptopropionic acid）]-β-CD（SACD）.The p H-responsive SACD/PEI smart nano oral drug delivery carrier was successfully constructed through the electrostatic interaction of SACD and positively charged polyethyleneimine（PEI）.The structure,morphology,size,surface charge,stability and p H response of SACD/PEI nanoparticles were comprehensively studied by UV-Vis,FT-IR,XRD,SEM,TEM,DLS,AFM and Zeta-potential techniques.The CSL was loaded in the core of SACD/PEI nanoparticles,which had high drug loading content（34.46 %）and entrapment efficiency（56.78 %）.The release curve imaged that the CSL release rate was less than 10 % in simulated gastric environment（p H=1.2）,while the CSL release rate was as high as 86 % in simulated colon environment（p H=8.5）.It implied that the drug-loaded nanoparticles CSL@SACD/PEI can protect gastric mucosa,avoid premature drug release and realize the targeted release of CSL in colon-site.Meanwhile,the drug-loaded nanoparticles CSL@SACD/PEI had good biosafety.It is worth mentioning that the drug-loaded nanoparticles CSL@SACD/PEI has stronger antitumor activity against three tumor cells（A549,HL-60 and SMMC-7721）and significantly reduced cytotoxicity to normal cells compared with free CSL.Moreover,it also showed excellent pro apoptotic effect of SMMC-7721 cells.The smart nano carrier provides an efficient and safe way for oral administration and targeted therapy.（3）The AβCD/SDS smart nanoparticles with p H and temperature dual response characteristics was designed and developed through amino groups modified β-CD（AβCD）possessing seven positively charged and anionic sodium dodecyl sulfate（SDS）.The AβCD/SDS nanoparticles were systematically studied by a series of techniques including UV-Vis,FT-IR,XRD,SEM,TEM,DLS,AFM and Zeta-potential experiments.The results showed that the nanoparticles have good stability and cyclic reversible self-assembly/disassembly properties.The AβCD/SDS nanoparticles was disassembled at 50 ℃ or under alkaline condition and re-assembled at 25 ℃ or under weakly acidic condition.It was further used as drug delivery carriers of anticancer drug methotrexate（MTX）,and the drug loading performance,stability and drug release behavior of the drug-loaded nanoparticles MTX@AβCD/SDS were investigated.In vitro release experiments displayed a relatively low release rate of MTX（14.5%）at37 ℃ and p H=2.0.Inversely,the release rate of MTX was 78 % at 42 ℃（tumor environment）and p H=8.5.It indicated that the AβCD/SDS nano materials are suitable for the targeted release of MTX in the colonic environment.Moreover,the cytotoxicity of drug-loaded nanoparticles MTX@AβCD/SDS to normal cells was greatly reduced,and the antitumor efficacy to two tumor cells（SMMC-7721 and SW480）and the induced apoptosis rate of SMMC-7721 cells were greatly higher than that of free MTX.The AβCD/SDS nano carrier provides a new choice for the targeted delivery of anticancer drugs in colon-site.（4）A kind of β-CD derivative bearing seven negatively charged was synthesized:per-6-deoxy-6-thiosulfate-β-CD（TSCD）.The TSCD/MCC smart nanoparticles with p H and butyrylcholinesterase（ACh E）dual response characteristics was constructed through TSCD and cationic myristoylcholine chloride（MCC）.The structure,morphology,surface charge,particle size,stability and stimulus response of TSCD/MCC nanoparticles were systematically studied by a series of techniques.Then,the natural active molecule triptolide（TPL）was loaded in the core of TSCD/MCC nanoparticles,which had high drug loading content（25.8 %）and entrapment efficiency（41.7 %）.Along with the p H value of the release system decreases from 7.4 to 5.0,the release rate of TPL was raised from 12.3 % to 65.6 %.Especially,when p H=5.0,after ACh E was added,the release rate of TPL increased significantly to more than 88 %.In addition,the drug-loaded nanoparticles TPL@TSCD/MCC showed better anticancer activity to four tumor cells（A549,HL-60,MCF-7 and SW480）and the higher induced apoptosis effect of A549 cells compared with free TPL,and the cytotoxicity to normal cells was lower.This novel drug delivery carrier with p H and enzyme dual response characteristics provides a positive role in guiding for the research and development of future antitumor drugs.