Study On The Application Of Shape Memory PLA-PU/DAuNPs Composite Membrane In Tumor Treatment

The treatment of tumor has always been the focus and difficulty in the field of medicine,more and more people pay attention to it.The most common methods of cancer treatment are surgery,chemotherapy and radiotherapy,as well as more modern therapies,such as immunotherapy,gene therapy,photothermal therapy,etc.However,there are some deficiencies in different treatment methods,so the treatment of tumor is moving towards the direction of combined treatment.At the same time,it is necessary to find drug carriers with high specificity,good performance,high encapsulation rate,reasonable release rate and few adverse reactions.Shape memory polymers have been widely used in biomedical fields,such as scaffolds for tissue engineering,implants for minimally invasive surgery,self tightening sutures,self retractable and mobile scaffolds,drug delivery systems,etc.Shape memory polymer has become a research hotspot in the field of medicine for controlling drug release and tumor treatment.Using shape memory polymer as drug delivery system can enhance drug targeting,and better control drug release,truly achieve high efficiency and low toxicity.As a new drug delivery system,gold nanoparticles have been widely studied.Gold nanoparticles can be loaded into anti-tumor drugs,play the role of photothermal while releasing drugs,and achieve the effect of chemotherapy and photothermal therapy.In this paper,firstly,gold nanoparticles containing doxorubicin（DAu NPs）were prepared by cobalt template substitution method.The spectral characteristics of DAu NPs were determined by UV-Vis spectrophotometer.The maximum absorption peak of DAu NPs was about 800 nm.The light energy could be converted into heat energy by near-infrared irradiation.The encapsulation efficiency of doxorubicin in DAu NPs was 42.43%.The release of doxorubicin in DAu NPs was investigated under different p H and near-infrared light.The cumulative release percentage of doxorubicin in DAu NPs was 80.55% after 9 hours of p H=6.The release of doxorubicin in DAu NPs was promoted by acid and near-infrared light.Then PLA-PU/DAu NPs composite thin films were prepared by spin coating.The results show that the shape recovery rate of the composite thin films can reach more than 90%.Good shape memory performance.Through the near-infrared light irradiation,the light energy can be better converted into heat energy.Water ball was used to simulate the in vitro injection of the composite thin films.The release of doxorubicin from PLA-PU/DAu NPs composite thin films in vitro was investigated under different conditions.The cumulative release of doxorubicin was81.93% 12 hours after irradiation of near-infrared light on the original shape of the experimental group.The thickness and surface shape of the composite thin films were observed by optical microscope and nano detection microscope respectively.The distribution of DAu NPs in the composite thin film was more uniform.The average thickness of the thin film was 4.90μm.According to the analysis of the infrared absorption spectrum of the composite film,the loading of DAu NPs has no obvious effect on the chemical structure of the polymer.The thermal properties of the composite thin films were analyzed by the secondary heating curve obtained by differential scanning calorimetry（DSC）.The loading of DAu NPs reduced the glass transition temperature and thermal stability of the original materials.Thermogravimetric analysis（TGA）can be used to analyze the thermal stability of the composite thin films.With the increase of temperature,three groups of samples began to decompose gradually,and the weight of the samples decreased gradually.The temperature of the composite thin films loaded with DAu NPs with the fastest decomposition speed is lower than that of PU-PLA composite thin films.In order to evaluate the combined therapeutic effect of the composite thin films on tumor,the cytotoxicity of the composite thin films was evaluated in vitro by MTT method.PU-PLA,PLA-PU/HAu NPs and PLA-PU/DAu NPs composite thin films had no cytotoxicity and did not affect the proliferation of normal cells.Hoechst 33342 staining method was used to evaluate the combined therapeutic effect of PLA-PU/DAu NPs composite thin film on tumor cells.In the PLA-PU/DAu NPs composite thin film group,doxorubicin was irradiated by near-infrared light to release from DAu NPs and play the role of photothermal,achieving the combined therapeutic effect of chemotherapy and photothermal therapy,with the strongest effect of killing human breast cancer cells.In order to improve the therapeutic effect of tumor,this paper adopts the combination of chemotherapy and photothermal therapy.In order to improve the concentration of the drug in the diseased area,the shape memory polymer PLA and PU were used as the substrate materials,loaded with drug loaded gold nanoparticles,and the composite thin films were prepared by spin coating method.The conditions were changed to change it into a temporary crimp shape.The composite thin films can be injected into the body.By using near-infrared light,the gold nanoparticles in the composite thin films can convert the light energy into heat energy,the composite thin films returns to its original shape and kills tumor cells.At the same time,antitumor drugs are released from the composite thin films to play a role.The composite thin films can better control the release of drugs,provide more possibilities for the high efficiency and low toxicity of anti-tumor drugs,and provide theoretical and experimental basis for further exploration of tumor treatment.