The Construction Of Stimuliresponsive Cyclodextrin Nanoparticles And Its Delivery To Anti-tumor Drugs

Stimuli-responsive supramolecular nanoparticle drug delivery system has an increasingly prominent advantage in cancer treatment,which enables it to receive widespread attention from scientists all over the world,and shows a good development prospect.Its advantages in the field of tumor treatment are as follows:（1）Improving the water solubility of anti-tumor drugs;（2）Prolonging the circulation time of drugs in the body;（3）Transporting drugs to tumor cells or tissues safely and effectively;（4）Achieving the controlled release of drugs by responding to various stimuli（such as p H,enzyme,temperature,light,etc.）;（5）Reducing the toxic and side effects of drugs while enhancing the therapeutic effect.Cyclodextrin（CD）is highly sought after by scientists because of its low cost,low toxicity,good water solubility,easy modification and good biocompatibility,and is frequently adopted as one of the components for the construction of stimuli-responsive supramolecular nanoparticles.In view of this,CD derivatives-based stimuli-responsive nanoparticles are constructed and applied as carriers of anti-tumor drugs,which provides theoretical and experimental basis for the construction of anti-tumor drug delivery system.The specific work has been carried out as follows:（1）An enzyme-responsive SCD/LCC nanoparticle was constructed based on the electrostatic interaction betweenβ-cyclodextrin sulfate sodium salt（SCD）and lauroylcholine chloride（LCC）.It was characterized by UV-Vis Spectrophotometer（UV-Vis）,X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,transmission electron microscope（TEM）,dynamic light scattering（DLS）and Zeta potential.The enzyme response behavior of SCD/LCC nanoparticles showed that the nanoparticles had a specific response to butyrylcholinesterase（BCh E）.The anti-tumor drug 10-Hydroxycamptothecin（HCPT）was selected as the drug model and successfully loaded onto nanoparticles.The in vitro release experiment determined that the cumulative release rate of HCPT could reach 66.6%in the presence of BCh E,while in the absence of BCh E,the release rate was only 23.7%.The cytotoxicity experiments showed that SCD/LCC/HCPT drug-loaded nanoparticles showed significant cytotoxic activity against five tumor cells,which had anti-tumor activity comparable to that of free HCPT,and higher than that of cisplatin.The hemolysis experiment confirmed that the drug-loaded nanoparticles have good biocompatibility and have the potential to be used in cancer treatment.In addition,cell apoptosis experiments showed that the apoptosis rate of SMMC-7721cells induced by drug-loaded nanoparticles was 55.3%,which was significantly higher than that of the blank control group（4.4%）,and the ability of inducing apoptosis was stronger than that of free HCPT.This study will provide a theoretical basis for the construction of a simple and efficient enzyme responsive drug loading system.（2）An enzyme-responsive BAEN-β-CD/HA nanoparticle was designed and prepared using polyamine modified BAEN-β-CD and hyaluronic acid（HA）as raw materials,and was characterized by various techniques such as XRD,FT-IR,TEM,and DLS.The enzyme response behavior of BAEN-β-CD/HA nanoparticles was investigated.The drug curcumin（Cur）was successfully loaded into the nanoparticles BAEN-β-CD/HA.In vitro release experiments showed that the release rate of Cur in the presence of hyaluronidase（HAase）（51.8%）was significantly higher than that in the absence of hyaluronidase（20.3%）.Cytotoxicity experiments showed that BAEN-β-CD/HA/Cur drug-loaded nanoparticles exhibited cytotoxicity to HL-60,SMMC-7721 and SW480 cells,and reduced the toxic side effects of free Cur on normal cells.In addition,cell apoptosis experiments showed that the apoptosis rate of HL-60 cells induced by drug-loaded nanoparticles was 40.2%,which was significantly higher than that of the blank control group（2.53%）.This work is helpful to provide some theoretical basis for the construction of stimuli-responsive drug delivery system in the future.（3）The electrostatic interaction between carboxymethyl-β-cyclodextrin（CM-β-CD）and ferrocene quaternary ammonium salt derivative(FC⁺₁₂Br^-)was used to construct CM-β-CD/FC⁺₁₂Br^-nanoparticles.The obtained nanoparticles exhibited spherical morphology with a particle size of about 220 nm and a Zeta potential of-16.9 m V.The p H response behavior of CM-β-CD/FC⁺₁₂Br^-nanoparticles was investigated.Celastrol（CSL）,a natural antitumor drug,was selected as the drug model and successfully loaded onto nanoparticles,and a good drug loading rate（20.2%）and high entrapment efficiency（92.5%）were obtained.The results of in vitro release experiments showed that the cumulative release rate of CM-β-CD/FC⁺₁₂Br^-/CSL drug-loaded nanoparticles in normal physiological environment（p H7.4）was only 17.7%,while in the simulated tumor cell microenvironment（p H 5.3）,the release rate was significantly increased to 50%.The cytotoxicity experiments confirmed that the nanoparticles had less cytotoxicity to human normal cells and had good biocompatibility.Drug-loaded nanoparticles showed significant anti-tumor activity against five tumor cells,showing the same anti-tumor activity as free CSL,and better than Cisplatin,reducing the toxicity and side effects of free CSL on human normal cells.In addition,cell apoptosis experiments showed that the apoptosis rate of SMMC-7721 cells induced by drug-loaded nanoparticles was 92.8%,which was basically the same as that of SMMC-7721 cells induced by free CSL.This work will improve the effective way for the controlled release of CSL in the tumor site.（4）Negatively charged sulfopropyl ether-β-cyclodextrin（SPE₇-β-CD）was synthesized.Subsequently,a p H-responsive SPE₇-β-CD/PEI nanoparticles was constructed using it and positively charged polyethyleneimine（PEI）,which was characterized by various techniques such as XRD,FT-IR,TEM,and DLS.The p H response behavior of SPE₇-β-CD/PEI nanoparticles was investigated.Doxorubicin hydrochloride（DOX）with high antitumor activity was successfully loaded into SPE₇-β-CD/PEI nanoparticles,and the drug loading rate and entrapment efficiency were 28%and 56%,respectively.According to the results of in vitro release experiments,the cumulative release rate of DOX reached 50.1%after 72 h in the simulated intestinal environment（p H 8.5）,while only 25.4%was released in the normal physiological environment（p H 7.4）,showing the performance of controlled release.This p H stimulus-responsive drug delivery system may be a strong candidate for oral administration.