Zwitterionic Hydrogel With Chemodynamic Therapy And Tumor Microenvironment Remodeling Properties For Postoperative Tumor Treatment

Surgical resection is the primary method for breast cancer.However,the residual tumor cells and highly immunosuppressive tumor microenvironment(TME)have a significant impact on tumor recurrence and metastasis.Postoperative implantation of in hydrogel system is a promising strategy owing to its effective and easy use for clinical.Among them,injectable hydrogels show great potential for drug delivery due to their uniform 3D porous network structure and extraordinary encapsulation ability after in situ formation.Chemotherapy drugs,various immunotherapeutic agents,and nanoparticles can be loaded into the hydrogelChemokinetic therapy(CDT)is a new therapeutic method,which kills tumor cells by converting hydrogen peroxide(H2O2)into highly toxic hydroxyl radical(·OH).In addition,it was reported that chemotherapeutic drugs doxorubicin(DOX)synergized with CDT exhibited enhanced anti-tumor efficacy,since DOX can not only directly kill tumor cells,but also induce anti-tumor immune response by inducing immunogenic cell death(ICD).In addition to residual tumor cells,postoperative immunosuppressive TME is also another important factor leading to tumor recurrence and metastasis.Therefore,this paper designed an injectable zwitterionic hydrogel system for killing residual tumor cells and remodeling immunosuppressive TME after surgery,which has the effect of preventing postoperative tumor recurrence.The main research contents are as follows:(1)The drug-loaded nanoparticles with the combined effect of chemotherapy and CDT were synthesized,and their physicochemical properties and in vitro cell biology were studiedThe CuO2/DOX nanoparticles were prepared through the coordination of H2O2 and Cu2+under alkaline condition,followed by the loading of DOX.To improve the targeting of tumor cells,the macrophage membrane was coated on the surface of nanoparticles(M/CuO2/DOX).The physicochemical properties of M/CuO2/DOX were characterized by Marvin particle size analyzer,transmission electron microscope(TEM)and X-ray photoelectron spectroscopy(XPS).Using 4T1 cells as a model,the uptake,cytotoxicity and ICD induction ability of M/CuO2/DOX were verified.The results showed that M/CuO2/DOX had satisfactory accumulation in tumor cells and the ability to induce apoptosis and ICD.(2)The zwitterionic hydrogel with anti-protein adsorption and degradation properties was synthesized and characterizedPoly(sulfobetaine methacrylate)(PSBMA)polymer was prepared by free radical polymerization of 3-[2-(methacryloyloxy)ethyl](dimethyl)-ammonio]-1propanesulfonate(SBMA).Driven by electrostatic interactions,PSBMA polymer could self-assemble into a hydrogel in saline.The successful synthesis of the PSBMA and PSBMA hydrogel was verified by 1H-NMR and FT-IR.The hydrogel’s porous structure was observed by scanning electron microscope(SEM).Bovine serum albumin(BSA)and 4T1 cells were selected as model proteins and cells to prove hydrogel’s good anti-protein adsorption and anti-cell adhesion properties.The good biocompatibility of hydrogel was verified by hemolysis experiment and cytotoxicity test.(3)M/CuO2/DOX and stimulator of interferon genes(STING)agonist 2’,3’-cGAMP loaded PSBMA hydrogel(Gel@M/CuO2/DOX/STING)was synthesized and their physicochemical properties were characterizedM/CuO2/DOX and 2’,3’-cGAMP were co-loaded in PSBMA hydrogel(Gel@M/CuO2/DOX/STING).Rheological behavior of Gel@M/CuO2/DOX/STING was measured by rheometer.The results of in vitro degradation and drug release showed that Gel@M/CuO2/DOX/STING could gradually degrade and release DOX in saline.(4)Gel@M/CuO2/DOX/STING for postoperative tumor treatmentGel@M/CuO2/DOX/STING was implanted into cavity after tumor resection.The hydrogel could be gradually degraded under physiological conditions and release M/CuO2/DOX and 2’,3’-cGAMP.M/CuO2/DOX could be selectively uptaken by tumor cells to kill tumor cells and induce ICD.2’,3’-cGAMP could activate STING pathway and upregulate interferon(IFN)signaling related genes,remodeling the immunosuppressive TME.In the 4T1 postoperative mouse model,Gel@M/CuO2/DOX/STING could kill residual tumor cells,promote the maturation of dendritic cells(DCs),enhance tumor-specific CD8+T cell infiltration,and ultimately prevent postoperative recurrence and metastasis.