Preparation Of Dextrin Polymer Nanomaterials And Their Application Of Curcumin Loading

Objective:Currently,chemotherapy is considered one of the most important options after surgical resection of primary tumours.Since the major difference between cancer cells and normal cells is the uncontrolled division and growth of cells,the principle of action of anti-cancer drugs is usually to inhibit the growth of cancer cells by interfering with the mechanism of cell division,such as inhibiting DNA replication or preventing chromosome segregation.However,most chemotherapeutic drugs have low specificity and selectivity and kill cells in normal tissue that is dividing,often to the detriment of healthy tissue that is functioning normally.Therefore,the search for more effective and less toxic cancer treatment strategies remains at the forefront of current research.Nanomaterials can not only deliver drugs directly to the focal area to improve efficacy and reduce side effects,but also have multiple delivery options of blood transport or local injection to exert effects directly in the focal area,enhancing anti-tumour efficiency while reducing damage to normal body tissues.Therefore,for the first time,we have constructed three new nano-drug carriers using maltodextrin,β-cyclodextrin,Fe₃O₄and folic acid and successfully loaded them with the anti-cancer drug curcumin to achieve good anti-cancer effects both in vivo and in vitro.Methods:1.The dextrin complex（MD-β-CD）was synthesized by cross-linking maltodextrin andβ-cyclodextrin via PDA,and further modified on Fe₃O₄by activation of the amino group of Fe₃O₄by APTES to obtain the magnetic nanomaterial Fe₃O₄-MD-β-CD.The nanomaterial FA-Fe₃O₄-MD-β-CD was modified on Fe₃O₄by reaction of hydroxyl group with activated carboxyl group in the presence of final NHS and EDC.The nanomaterials FA-Fe₃O₄-MD-β-CD were obtained by Fourier infrared spectroscopy（FTIR）,zeta potential,particle size and other methods.2.Curcumin was used as an antitumor drug in this paper.The loading capacity of different nanomaterial complexes on curcumin was investigated by drug loading kinetics.The ability of the three nanomaterials to release curcumin under different pH conditions was compared.Hep G2 cells,Hela cells and MCF-7 cells were co-cultured with the nanomaterials to observe the drug release and anti-tumour ability in vitro.3.A mouse tumour model was constructed and control groups were set up:material group,drug group,control group（PBS）and nanomaterial loaded drug group to compare the anti-tumour ability under different conditions and the weight of mice in each group was recorded daily for any abnormalities.Finally,the vital organs of the mice in different groups were stained with HE to detect whether the nanomedicine had any adverse effect on the internal organs of the mice.Results:1.Nanomedicine carriers（MD-β-CD）were successfully prepared.The polysaccharide polymer maltodextrin is relatively resistant to different physicochemical properties such as acid and heat and easy to modify due to its abundant hydroxyl groups on the surface,making it possible to use the polysaccharide polymer maltodextrin as a backbone for linked nanomaterials.β-cyclodextrin（β-CD）is a cyclic oligosaccharide consisting of seven D-glucopyranoside units that linked by1,4-glycosidic bonds.The molecule has a truncated cone shape and is a popular choice for the synthesis of nanomaterials as its specific conformation provides a rich internal space for encapsulating a range of drugs.In the present work we have subjected maltodextrin andβ-cyclodextrin to direct cross-linking polymerisation using PDA anhydride and the condensed product is rich inβ-cyclodextrin and maltodextrin.Due to the special structure of theβ-cyclodextrin it can be used to trap and retain a certain amount of the drug,making it a nano-carrier for the drug.Maltodextrins with low surface energy and high surface activity are also able to adsorb anti-cancer drugs to a certain extent to improve drug loading efficiency.The drug loading kinetics experiments confirmed that the MD-β-CD synthesized by us is mainly loaded with the anticancer drug curcumin by chemisorption.Under the tumour microenvironment pH5.3,the drug release was significantly better than the physiological condition of pH7.4,indicating that the synthesized drug carriers are pH-responsive.In vitro cellular uptake experiments showed that the synthetic nanomaterial carriers have good release properties and can release the drug in the in vitro cellular environment and be taken up by the cells.In an in vitro anti-tumour assay,MD-β-CD loaded with curcumin showed excellent killing effect on Hela,Hep G2 and MCF-7 cell lines,with the first two being the most superior.2.Based on MD-β-CD,we successfully prepared a magnetic nano-drug carrier（Fe₃O₄-MD-β-CD）with similar physicochemical properties,characterization,and biological compatibility to MD-β-CD,which also has a certain pH responsiveness with better release in the tumor microenvironment at pH 5.3 than under physiological conditions at pH 7.4.In an in vitro killing assay of three types of cancer cells,the nanomaterials MD-β-CD and Fe₃O₄-MD-β-CD both showed the best anti-cancer effect with Hep G2.And by modifying MD-β-CD on Fe₃O₄,it makes MD-β-CD with magnetic targeting after modification on Fe₃O₄,which can achieve enrichment of tumor local tissues under the action of external magnetic field to reduce the blood concentration of systemic drugs and reduce side effects.3.Since both the nanomaterial MD-β-CD and Fe₃O₄-MD-β-CD are optimal in anti-cancer effect with Hep G2,and the percentage of patients with two or more cancers at the same time is extremely low in the clinic.Therefore,based on the first two,we chose to synthesize FA-Fe₃O₄-MD-β-CD by grafting folic acid onto Fe₃O₄-MD-β-CD to further increase its anti-hepatocellular carcinoma effect.Folic acid is a water-soluble vitamin,also known as pteroyl glutamate,which is absorbed in the upper part of the small intestine.After absorption,folic acid participates in the enterohepatic circulation and is stored in the body in the intestinal wall,liver and other tissues.The abundant folate receptors in the enterohepatic circulation and the abundant folate receptors in the tumour cells make FA-Fe₃O₄-MD-β-CD more easily captured by liver cancer cells,thus obtaining biological targeting of liver cancer in vivo as well.In this way,a nanomaterial with dual targeting"in vitro magnetic targeting"and"in vivo biological receptor targeting"has been successfully constructed.Conclusion:In summary,a variety of novel nanodrug carriers were successfully constructed in this study,namely MD-β-CD,Fe₃O₄-MD-β-CD,FA-Fe₃O₄-MD-β-CD and loaded with the anticancer drug curcumin through supramolecular interactions（hydrogen bonding,π-πstacking and hydrophobic interactions）.The three prepared nano-drug carriers have the following characteristics,with good biocompatibility,drug loading and release capacity.They are pH-responsive,have excellent in vivo and ex vivo anti-cancer effects,can achieve dual targeting of magnetic and biological targeting and can be delivered locally to reduce systemic dosing and thus reduce the toxic side effects of conventional chemotherapy.The three nano-drug carriers prepared have the following innovative features:（1）the nano-carrier MD-β-CD is used to improve the stability and water solubility of the anti-cancer drug curcumin,which enables the release and effect of curcumin inside tumour tissues and has good stability and anti-tumour effect in inducing apoptosis of tumour cells;（2）by grafting MD-β-CD onto Fe₃O₄,the nano-materials have magnetic targeting properties and can be used in vitro for the treatment of cancer.（2）By grafting MD-β-CD onto Fe₃O₄,the nanomaterials are magnetically targeted and can be locally enriched in the presence of magnetic fields in vitro,and the magnetic nanomaterials also have potential applications in magnetic imaging;（3）Based on the in vitro anti-cancer experiments in the previous two parts,we chose to further enhance their effects on liver cancer cells by grafting folic acid onto Fe₃O₄-MD-β-CD,making our materials not only magnetically targeted in vitro but also biologically targeted in vivo.It also has some bioreceptor targeting ability.（4）Good biocompatibility and high stability,our synthesised nanomaterial FA-Fe₃O₄-MD-β-CD showed no adverse effects in cytotoxicity assays,haemolysis assays and HE staining of vital organs in mice.Using these advantages,the nanomaterials can significantly improve tumour suppression efficiency and therapeutic safety,providing a new therapeutic strategy for tumour cell-targeted therapy.The constructed nanomaterials can be used for the synergistic treatment of tumour chemotherapy,further reducing the side effects of systemic drug administration.In conclusion,this novel nano-drug delivery system has potential applications in cancer diagnosis and treatment.