Research On Synergistic Treatment Of Tumor With Polydopamine Based Nanoparticles

Today,cancer is still a disease with no complete cure.And the risk is increasing every year.Cancer kills millions of people around the world every year.Therefore,early detection and early treatment of cancer is of great significance to human beings.However,different tumor sites and different time periods will lead to different treatment methods.Cancer is usually diagnosed by imaging and cytopathology,and treated with drugs,radiation or surgery.In recent years,various functional materials have been widely used in tumor diagnosis and treatment,especially nanomaterials,such as contrast agents for molecular imaging based magnetic resonance imaging（MRI）,photoluminescence imaging（PL）,etc.For example,used for light treatment The treatment of used for drug-loading nanoparticle carrier materials Nanometer material which is used to contrast agents can be used to enhance the tumor region and normal tissue contrast,make tumor area can be more clear,convenient for medical personnel to carry on the real-time diagnosis So it is of medical integration multifunctional nanomaterials in biomedical application of diagnosis and treatment of tumor is of great significance.Based on the above,in the second chapter of this paper,polydopamine（PDA）was prepared by simple self-polymerization and loaded with Mn²⁺with MRI and fluorescent dye IR780 by means of complexation.Nanospheres of uniform size were synthesized.Its size is about 200nm,and after being dispersed in deionized water and stored at 4℃for four weeks,the hydrated particle size still has no obvious change.In the UV-Vis absorption spectrum,the final product shows a high absorption peak at about 800nm in the near infrared region,indicating that it has a strong light absorption ability in the near infrared band,and can be used as a photothermal conversion material for photothermal therapy.Therefore,the use of fixed near-infrared light of 808nm irradiation,photothermal effect test can be seen that it shows a good thermal capacity,the maximum temperature of 58℃has far exceeded the thermal ablation temperature of tumor cells（42℃）.Mn O₂binding can be converted into bivalent Mn²⁺according to the tumor microenvironment in acid response,thus guiding MRI.MRI tests using a 3.0T magnetic resonance scanner in clinical trials show that Mn O₂binding can show good MRI signal enhancement effect.All of the above tests indicate that the end product is a photothermal agent with MRI-guided photothermal therapy（PTT）that is responsive to the tumor microenvironment.In the third chapter,the calcium carbonate（Ca CO₃）nanospheres complexed with the chemotherapy drug doxorubicin（DOX）are firstly prepared,and then a layer of polydopamine containing Gd₂O₃nanoparticles is wrapped on it.The final product is black in water.The nanoparticle size of the product is uniform,about 130nm.The final product has a high absorption peak in the near infrared region under the UV-Vis absorption spectrum test,and the photothermal test in vitro shows that it can still achieve the photothermal killing effect of tumor cells.Calcium carbonate can act as the response mechanism of tumor microenvironment and decompose through the acidity of tumor microenvironment to release the complex anticancer drug doxorubicin,forming a synergistic treatment system combining photothermal therapy and chemotherapy.At the same time,because DOX can release drugs at the tumor site in response to stimulation,it avoids the powerful killing power of chemotherapy drugs to normal cell tissues.At the same time,combined Gd³⁺can be used for MRI guidance,which can be verified in the results of its test MRI scanner.Thus it is possible to combine diagnosis with treatment and to use stimulus-responsive synergistic therapy for tumor treatment.