Construction Of Gold-Polydopamine Nanoprobes And Their Application In Visualized Theranostics Of Tumor

Malignant tumors are seriously threatening human life,and phototheranostic nanoprobes based on gold nanomaterials have important applications in visualized theranostics of tumors.In this dissertation,by synthesizing gold nanobipyramids(AuNBPs)and gold nanoclusters(AuNCs),visualized theranostic nanoprobe with photoacoustic(PA)imaging/photothermal therapy(PTT)/chemotherapy and bifunctional nanoprobe with PTT/photodynamic therapy(PDT)were respectively constructed.The main results were summarized as follows:(1)Doxorubicon(DOX)-loaded,and polydopamine(PDA)-coated AuNBPs nanocomposites with core-shell structure were constructed,and the obtained AuNBPs@PDA-DOX nanoprobes were applied in PA imaging and synergistic PTT/chemotherapy of 4T1 tumors.Compared with single AuNBPs,AuNBPs@PDA showed enhanced PA imaging and photothermal conversion performance,in which the photothermal conversion efficiency can be improved from 30.75%to 42.07%.Under the condition of low-dose 808 nm laser irradiation(1.0 W/cm~2)and low-concentration AuNBPs@PDA-DOX(60μg/mL),the 4T1 cell viability was reduced to below 5%.By the combination of PTT/chemotherapy,the 4T1 tumors were completely cured after 14-day treatment.(2)PDA-coupled AuNCs nanocomposites(PDA-AuNCs)with excellent photothermal conversion and reactive oxygen species(ROS)generation were synthesized,in which AuNCs were used as photosensitizer for PDT and PDA was used as photothermal conversion agent for PTT.Under the irradiation of 808 nm and 635 nm laser,the photothermal conversion efficiency and ROS yield were measured to be 34.6%and40%,indicating the potential application of PDA-AuNCs as bifunctional nanoprobes for PTT/PDT.