Composites Of PEGMa Modified Molybdenum Oxide And Thermal Responsive Microgel And The Photothermal Property

The photothermal ablation(PTA)therapy,as a high efficiency,fast,minimally invasive,small side effects therapeutic methodology,employs hyperthermia generated by photothermal agents from near-infrared(NIR)laser energy to kill cancer cells.Especially,as the photothermal agent,Mo Ox exhibited pH-dependent degradability in vivo.However,the rapid degradation of Mo Ox at physiological pH values would decrease the NIR photothermal effect.In order to well utilize the degradation properties of Mo Ox,methacrylic acid(MAA)monomer was introduced to control the p H meanwhile synthesizing composite microgels with N-isopropylacrylamide(NIPAM).So,in the present paper,the PEGMa-Mo Ox/p(NIPAM-co-MAA)microgel(NCs)was designed and prepared to form the triple responsive nanomaterial.Firstly,the molybdenum oxide was modified by polyethylene glycol methacrylate(PEGMa)with molecular weight of 400.Because the molybdenum oxide could be reduced and stabilized by PEGMa and would show photothermal efficiency.The PEGMa-Mo Ox nanoparticles with different size and photothermal efficiency were prepared by a “one-pot” hydrothermal method.the 808 nm laser irradiation result revealed that PEGMa-Mo Ox nanoparticles could transform light into thermal energy.Then,the FTIR result indicated the existence of C=C group,which could further supply the reaction ability with other monomer.Moreover,we attempted to obtain the experimental conditions for preparing p(NIPAM-co-MAA)microgel with controlled size.By adjusting the surfactant amount,the microgels with different size were prepared by emulsion-polymerized method,and the particle size becomes smaller as the surfactant amount increased.The curve of transmittance varies with the temperature suggested that the p(NIPAM-co-MAA)microgel had temperature/ pH response.Meanwhile,the LCST test result showed that the added MAA could elevate the LCST of PNIPAM microgel.Afterwards,the PEGMa-Mo Ox/p(NIPAM-co-MAA)(NCs)composite microgel was synthesized by emulsion polymerization.Through adding MAA monomer provided an acidic condition(p H at 3-5)to delay the degradation of the PEGMa-Mo Ox and endow NCs pH response properties.The UV-Vis spectrophotometer and 808 nm laser irradiation test results indicated that the introduced MAA could stabilize the photothermal properties of composite microgels.Meanwhile,the LCST measure result suggested the NCs had pH-dependent thermal response.Finally,the PEGMa was added again for enhancing the photothermal efficiency of the NCs to react with molybdenum oxide again.The 808 nm laser irradiation result showed that the adding of 2.5 g PEGMa could raise the temperature of NCs by 27 oC,which suggested that the introduced PEGMa could improve the photothermal conversion performance.Through the above design and analysis,we successfully synthesized the multi-functional PEGMa-Mo Ox/p(NIPAM-co-MAA)NCs composite microgel with triple response,which had a great superiority for NIR-induced photothermal therapy.The multi-functional performance in biomedical field applications would have great potential.