Preparation And Photothermal Conversion Properties Of Pt₃Ni-S Nanoalloy

In recent years,people are facing with three major health problems: unsafe drinking water,bacterial infections,and malignant tumors.Therefore,more and more researchers are committed to developing corresponding strategies to solve the above-mentioned thorny problems.Desalination of seawater and removal of toxic heavy metal ions or organic dyes from industrial wastewater are effective strategies to solve the freshwater crisis,which is essential for human survival and development.Solar energy is a kind of renewable energy with development potential.It is of great significance to produce safe drinking water for human use using solar energy-driven seawater desalination or industrial wastewater purification.It is well known that open wounds are susceptible to external bacterial infections,which can lead to severe wound inflammation and even causing human death.Therefore,the treatment of bacterial infections has received extensive attention from medical workers.At present,bacterial infections are mainly treated with antibiotics,but the abuse of antibiotics can cause pathogens to develop drug resistance,leading to antibiotic treatment failure.In recent years,researchers have developed some non-antibiotic therapies to combat bacterial infections.The most typical method is to use the photothermal effect of nanomaterials for antibacterial.Malignant tumors have become the most serious and complicated diseases that humans are facing.Traditional tumor treatment methods have many disadvantages.For example,surgical resection is more traumatic to the human body,radiotherapy can kill normal tissue cells and cause serious side effects,and chemotherapy is usually poorly targeted,and it is easy to cause damage to human organs.Therefore,photothermal therapy(PTT),which has the advantages of noninvasive,simple operation,significant curative effect,and high specificity,has attracted wide attention from researchers.In summary,solar-driven water evaporation,photothermal antibacterial and photothermal treatment of malignant tumors require nanomaterials with excellent photothermal conversion properties.Among many materials,noble metal nanomaterials can be used as good photothermal conversion materials because of their typical local surface plasmon resonance(LSPR)effect.Among them,platinum(Pt)had the advantages of excellent photothermal conversion performance,good biocompatibility,strong mechanical properties,and catalase-like activity,and so on.In recent years,it has been widely used in the field of photothermal conversion.However,due to the high price of Pt,in order to reduce costs and optimize performance,platinum-nickel alloy materials were selected in this paper to convert light energy into heat energy for solar-driven water evaporation,photothermal antibacterial,and photothermal antitumor.The specific research contents were as follows:(1)Platinum nickel alloy(Pt₃Ni-S)nanowires were prepared by hydrothermal method,and polytetrafluoroethylene(PTFE)film(Pt₃Ni-S@PTFE)deposited by Pt₃Ni-S was further prepared by casting method.Pt₃Ni-S@PTFE had excellent photothermal properties and resistance to strong acid/alkali.Under the irradiation of simulated sunlight,the high-efficiency evaporation of strong acid(evaporation rate 0.93 kg m^-2h^-1)/strong alkali(evaporation rate 1.04 kg m-2 h^-1)solution was realized.Pt₃Ni-S@PTFE could also remove toxic heavy metal ions from industrial wastewater by solar-driven water evaporation(removal rate as high as 99.99%).In addition,the mechanism of the high surface mechanical properties of Pt₃Ni-S@PTFE was deeply explored through theoretical calculations.(2)A novel Pt₃Ni-S@HA hydrogel was obtained by mixing Pt₃Ni-S nanowires and hyaluronic acid(HA)nanohydrogels.Pt₃Ni-S@HA had excellent photothermal properties and could realize photothermal antibacterial;simultaneously,Pt₃Ni-S could be used as a peroxidase-like enzyme to catalyze hydrogen peroxide(H₂O₂)to generate hydroxyl radicals(·OH)to kill bacteria,which realizes synergistic antibacterial of chemical kinetics and photothermal.Compared with single-mode therapy,synergy treatment could increase the mortality of E.coli.In addition,hyaluronic acid could not only enhance the adhesion of bacteria and improve the efficiency of sterilization,but also promote wound healing and shorten the treatment cycle.Therefore,Pt₃Ni-S@HA hydrogel could be used as promising and highly effective antibacterial agents against pathogenic microorganisms such as E.coli.(3)Pt₃Ni-S nanowires had excellent optical absorption characteristics and photothermal stability,which could be used for photothermal therapy and photoacoustic tomography imaging of tumors.In addition,Pt₃Ni-S nanowires had peroxidase-like properties,which could catalyze H₂O₂ to generate highly cytotoxic ?OH to achieve chemokinetic therapy.The Pt₃Ni-S nanowire contained Pt element with high atomic number(Z = 78),which could be used for CT tomographic imaging.In vivo antitumor results show that Pt₃Ni-S combined with exogenous H₂O₂ can achieve high-efficiency tumor ablation.Compared with the noble metal Pt alone,Pt₃Ni-S nanowires had higher peroxidase activity and could be used for multimodal imaging-mediated photothermal and chemical kinetic synergistic treatment of tumors.