Preparation And Properties Of Rare Earth-doped Nano-tungsten Oxide Phototherapeutic Agent

Compared with traditional cancer treatment methods such as surgery,radiotherapy,chemotherapy,etc.,near-infrared light-induced cancer treatment methods have attracted people's attention due to their non-invasiveness,high selectivity,no drug resistance and less damage to normal tissues.It mainly includes photothermal therapy(Photothermal therapy,PTT)and photodynamic therapy(Photodynamic therapy,PDT).For near-infrared region?light(780-950 nm),near-infrared region?light(1000-1700 nm)has longer emission wavelength,deeper tissue penetration depth,and smaller background fluorescence effect.The treatment efficiency will be significantly improved and the key lies in the development of an efficient photodiagnostic agent if multimodal imaging can be supplemented in synergistic phototherapy.The transition metal oxide WO_3-x can absorb near-infrared light to realize photothermal synergistic photodynamic therapy due to its surface plasmon resonance effect.It can simultaneously realize CT imaging because of the large atomic number of W.Based on these above,the research contents of this paper are as follows:The W₁₈O₄₉ nanophototherapeutic agent with good crystallinity and uniform morphology was prepared by solvothermal method that n-propanol was used as solvent.Photothermal and photodynamic properties of samples with different concentrations and different times was comparatively studied under the photoresponse of near-infrared region?(808 nm)and near-infrared region?(1064 nm).It has CT imaging capabilities at the same time.Further in vitro cell experiments show that the sample has good biocompatibility to normal human cells,and has a strong killing effect on tumor cells.CT imaging has some shortcomings,such as poor spatial resolution and ray radiation,and MRI imaging can display slice images at any angle,and has a soft tissue resolution several times higher than CT.Combining MRI and CT can better achieve monitor.Gd-doped W₁₈O₄₉ nanophototherapeutics were prepared by one-step solvothermal method(the molar doping ratios of Gd were 2%,3%,4%,and 5%,respectively).The MRI and CT dual-mode imaging were simultaneously achieved.The photothermal and photodynamic properties of the samples with different concentrations and times were compared and studied under different wavelengths of near-infrared light.The results show that the doped samples have high photothermal conversion efficiency and photodynamic effects,and also simultaneously realize in vivo and in vitro MRI and CT dual-mode imaging.The hypoxic environment of the tumor will weaken the effect of actual photodynamic therapy,and the effect can be compensated by the redox reaction between Ce ions and in situ hydrogen peroxide in the tumor microenvironment to generate oxygen.Based on this,Ce-doped W₁₈O₄₉ nanophototherapeutic agent was prepared by a one-step solvothermal method(the molar doping ratio of Ce was 3%,5%,7%,and 15%,respectively).Under different wavelengths of near-infrared light,the photothermal and photodynamic properties were studied by changing the concentration and illumination time of the sample.The results show that the sample with a doping content of 3%has a high photothermal conversion efficiency.Simulation of the reaction with hydrogen peroxide in the tumor microenvironment showed that the doping of Ce significantly enhanced the photodynamic effect,and the samples had CT imaging capabilities.