Preparation Of Integrated Diagnosis And Treatment Metal Nano-probes By Photocatalytic Reduction And Their Application In Biomedicine

Cancer is a serious threat to human health and life.Especially in developing countries,due to less effective screening technology and low level of early diagnostic technology,cancer is generally found late,coupled with low efficacy,side effect,high recurrence and metastasis rate,poor accuracy etc.in cancer treatment,complete cure is more difficult.Therefore,it is a great significance to explore safe and simple technique of diagnosis and treatment to improve the survival rate of cancer patient.Nanoprobe with the characteristics of multi-mode imaging can realize different imaging information obtained from the single contrast agent.More disease information can be obtained from multi-modal imaging,and multi-mode imaging is of great help to improve the accuracy of early diagnosis and reduce the risk of misdiagnosis.For the treatment of tumors,in addition to traditional methods such as surgery,radiotherapy and chemotherapy,photothermal therapy(PPT)as an effective treatment for cancer has aroused widespread attention.Current clinical studies show that PTT not only has toxic effect directly on tumor but also can enhance the efficacy of chemotherapy and inhibit cancer recurrence and metastasis in combined therapy.In summary,the research is divided into the following parts:(1)N doped graphene quantum dot(N-GQD)was synthesized by hydrothermal method using citric acid and urea.N-GQD had a uniform size of about 5 nm.The two fluorescence emission peaks,one in visible light region showed 49.75 % quantum yield,while another in the near infrared region was 2.49 %.The photothermal conversion efficiency was 62.53 %.The probe also had low cytotoxicity and ability of photoacoustic response.After coupling folic acid,it presented imaging and photothermal therapy on the cells.(2)N-GQD and gold chloride were mixed and irradiated with ultra-violet(UV)radiation for 1 min.Then,the gold nanosphere cluster with the diameter of 50 nm and coating by NGQD was formed using a facile one-step approach.The nanoprobe had good dispersion,stability,excellent photoacoustic imaging(PAI)and computed tomography(CT)imaging performance,low cytotoxicity and high photothermal conversion efficiency.Targeted PAI/CT imaging of tumor after modification of folic acid(FA)could be obtained using the probe.Meanwhile,after the adsorption of doxorubicin(DOX),the chemo-photothermal combined therapy for tumor could be carried out through controlled drug release from GQD under heated and acidic environment of tumor.(3)Bismuth particles imbedded nanohydrogel(Bi@CMC)was synthesized with UV irradiation.The size of Bi@CMC was about 35-80 nm,and the bismuth particles inside were about 5 nm.The Bi@CMC had good stability,dispersibility,high photothermal conversion efficiency and low toxicity.After adsorption of DOX,a multi-functional nanoprobe(DOX/Bi@CMC)integrating PAI/CT dual-mode imaging and photothermal/drug dual-mode therapy was obtained.After irradiation with near-infrared region laser,the probe could not only generate heat effect,but also release drug thoroughly by nanohydrogel disintegration,achieving the purpose of chemo-photothermal combined therapy.(4)Nano-bismuth-sphere-cluster(Bi)with function of computed PAI/CT dual-mode imaging was synthesized by one-step method after irradiation with UV for 3 min.Bismuth potassium citrate granule,which was a common gastric drug with the characteristics of high safety and low price(<1 RMB/g)was the only raw material.It showed that the Bi cluster had uniform size,good stability,high photothermal conversion efficiency and low toxicity.After adsorption of DOX,it could be directly used in animal experiment.Results showed that drug could be released through near-infrared laser and acidic environment of the tumor,so as to achieve the purpose of chemo-photothermal combined therapy.This paper is devoted to explore a simple method,using the common security of raw materials,synthetic security and stability of cheap effective multifunctional nano probes,to explore the new treatment integrated probe provides a new train of thought,is expected to provide the basis for early diagnosis and treatment of tumors.