Anti-tumor Properties Of Functional Molybdenum Selenide Nanomaterials

Cancer has become one of the most serious diseases in human beings,which with high mortality and low cure rate.However,conventional clinical treatment methods such as radiotherapy and chemotherapy have great toxic,side effects and difficult to cure.Therefore,it is urgent to research effective anti-tumor strategies.Optical therapy has become a potential anticancer strategy due to its advantages of minimally invasive,spatiotemporal selectivity,low drug resistance and high therapeutic efficiency.Among them,photothermal therapy(PTT)and photodynamic therapy(PDT)have broad application prospects for cancer treatment in overcoming the limitations of traditional chemotherapy.The choice of light source is an important premise in optical therapy.Compared with the destructive effects and side effects of ultraviolet and visible light on normal tissues or cells,NIR light reveals strong tissue penetration and low additional damage,which can directly reach the lesion and achieve efficient treatment.Currently,more and more researchers are working on the development and exploration of NIR responsive materials.Two-dimensional(2D)layered transition metal sulfides are widely studied for their excellent photoelectric property,electronic conductivity and moderate band gap.Among the numerous transition metal sulfides,MoSe2 is considered as one of the most promising NIR responsive materials due to its suitable band gap(1.33-1.72 e V),excellent photothermal/photodynamic performance and strong capturing ability of NIR light.Therefore,we have been synthesized MoSe2 nanomaterials and their composites with different morphologies,and performed a series of structural and performance characterization on all prepared materials.On this basis,some generated active sites by the large surface area of the material were used to load the anticancer drugs,and effectively synergistic photothermal,photodynamic and chemotherapeutic treatments were achieved.The specific research contents are as follows:(1)The construct of a nanoplatform to integrate multitherapy has attracted most attention on cancer treatment.Herein,selenide molybdenum(MoSe2)nanoflowers were synthesized as nanocarriers to reveal the NIR-mediated synergetic photothermal therapy(PTT),photodynamic therapy(PDT),and drug release.All the MoSe2 nanoflowers(150 ~ 180 nm)were assembled by many thin nanosheets about 3 ~ 4 layers of MoSe2.With the novel hierarchical nanostrucutre and small band gap(1.24 e V),the as-synthesized MoSe2 possess strong near-infrared(NIR)absorption and high photothermal conversion(61.8%).In addition,it also exhibit the NIR stimulated ·OH generation and it is the first time to use MoSe2 nanostructure as PDT agent.The mechanism was investigated,showing that the sufficient photo-excited electrons,high O2 and H+ concentration are in favour of ·OH production of this kind of PDT agents.After PEGylation,MoSe2@PEG exhibit high Dox loading capacity due to the electrostatic and ?-? stacking interaction(MoSe2@PEG-Dox),which exhibits the acid/photothermal triggered drug release.The synergistic effect of chemotherapy,PTT,and PDT further induces the superior cancer cell apoptosis and improved antitumor effectiveness.(2)The development of nanotheranostic agent with image guided highly therapeutic efficiency has attracted most attentions on tumor treatment.Herein,the novel MoSe2/Bi2Se3 nanosheets were designed to integrate CT/photothermal(PT)imaging and photodynamic/photothermal/chemo-therapy(PDT/PTT/chemotherapy)into one nanoplatform.Firstly,the MoSe2 nanosheets(5 ~ 30 nm)were prepared via ultrasound-assisted exfoliated method,and then by a cation-exchange strategy the novel sandwich nanostructure Bi2Se3/MoSe2/Bi2Se3(Bi-M-3)were obtained,revealing the narrower band gap(1.17 e V)and the stronger near-infrared(NIR)absorption.Both experimental and density functional theory(DFT)calculations reveal the Z-scheme mechanism of charge transfer in the heterostructure,which induces the enhanced ROS(?OH)generation due to the efficient separation of photogenerated electron-hole pairs.Meanwhile,the nanoheterostructure also makes sure the improved photothermal conversion efficiency(59.3%).Besides,we also found the photothermal effect can promote the transfer photo-generated electron that is in favor of ROS generation.Furthermore,because of the higher absorption coefficient of X-ray for Bi atom,the heterostructure also exhibits the higher CT imaging ability than pure MoSe2 sample.After the loading of anticancer drug Doxorubicin(Dox),Bi-M-3@PEG-Dox displays the acid/photothermal sensitive drug release behavior.The synergistic effect of chemotherapy,photodynamic and photothermal therapy further induces the superior cancer cell apoptosis and enhanced antitumor effect.(3)Here,a hollow structure of MoSe2 nanospheres with a size about 180 nm were synthesized by a simple solvethermal method,and the prepared Fe3O4@PEI nanoparticles were loaded onto the surface of hollow MoSe2 nanospheres via electrostatic action to form MoSe2/Fe3O4(MF-2)nanocomposite.The composite system has excellent near infrared absorption performance and narrow band gap(1.39 e V).Under the irradiation of near-infrared laser,the system reveals an excellent photothermal performance,and its photothermal conversion efficiency is as high as 66.2%.In addition,the NIR response photodynamic performance of prepared material is also studied.In order to further enhance its photodynamic effect,we used the rich cavity of MoSe2/Fe3O4 nanospheres to load O2@PFC,so as to overcome the hypoxic microenvironment in the photodynamic therapy(PDT),and the photodynamic therapy effect of the O2@PFC@MF-2 was improved more than 3 times.Similarly,the anticancer drug of Dox was loaded onto the MF-2@PEG materials through electrostatic interaction and ?-? staking for chemotherapy.In addition,we also integrated the high absorption performance of Mo atoms for X-ray,the high relaxation efficiency of Fe3O4 and the outstanding photothermal conversion ability of MoSe2 to develop a multi-mode CT/MR/IR imaging diagnosis system.Thus,the triple-model CT/MR/IR imaging guided PTT/PDT/chemo-therapy anti-tumor system O2@PFC@MF-2@PEG/Dox can inhibit tumor growth effectively and accurately,and promotes the apoptosis of cancer cells.