Application Of Pt Based Nanocomposites In Tumor Diagnosis And Treatment

Cancer is one of the major diseases that seriously threaten global public health.However,the first-line treatment modalities for cancer,such as surgery,chemotherapy and radiotherapy,are limited by the side effects and remarkable systematic toxicity.As the emerging treatment modalities,photothermal therapy?PTT?,photodynamic therapy?PDT?and chemodynamic therapy?CDT?have become potential anti-cancer strategies owing to their negligible invasiveness,low toxicity and high selectivity.However,due to the intrinsic defects of each monotherapy and complex TME,the tumor growth is difficult to be inhibited completely by monotherapy.Therefore,synergistic therapy,a method of combining multiple treatments to treat cancer,is often used to conquer the insufficient tumor suppression effect of monotherapy due to great enhanced therapeutic effect and weakened side effect.Moreover,synergistic therapy has attracted more and more attention because it can greatly enhance the therapeutic effect and reduce the side effects.In this paper,Pt based nanozyme is used to achieve the synergistic therapy by their materials,enzyme activities and combination of photosensitizers.The specific contents can be summarized as follows:?1?The new Au₂Pt nanozymes were synthesized in one step at room temperature.To obtain Au₂Pt-PEG-Ce6,SH-PEG-NH₂ was bonded to Au₂Pt nanozymes and the photosensitizer chlorin e6?Ce6?is covalently linked to Au₂Pt nanozymes for photodynamic therapy?PDT?.Interestingly,the Au₂Pt-PEG-Ce6 nanozymes possess catalase-and peroxidase-like activities simultaneously,which can not only generate O₂ for relaxation of tumor hypoxia and enhancement of PDT efficiency but also produce?OH for chemodynamic therapy?CDT?.Furthermore,owing to the strong absorption in near-infrared?NIR?region,Au₂Pt-PEG-Ce6 can be served as photothermal transition agent for NIR-responsive PTT and provide the possibility for photoacoustic?PA?and photothermal?PT?imaging.Meantime,the excellent X-ray attenuation capability of Au and Pt elements endows Au₂Pt-PEG-Ce6nanoformulation with the ability to act as an X-ray computed tomography?CT?imaging contrast agent.It can realize PA/PT/CT imaging-guided synergistic PTT,PDT,and CDT.?2?PtBi nanozyme was synthesized by one-step method and?-cyclodextrin was modified on its surface to make it has good biocompatibility,then Ce6 was loaded for PDT.The PtBi nanozymes possess catalase-like activities,which can generate O₂ for relaxation of tumor hypoxia and enhancement of PDT efficiency.Furthermore,owing to the strong absorption in NIR-I and NIR-II region,PtBi-?-CD-Ce6 can be served as photothermal transition agent for NIR-I and NIR-II responsive PTT and provide the possibility for photoacoustic?PA?and photothermal?PT?imaging.Both in vivo and in vitro experiments show that it can be used as an effective cancer agent.