Two-dimension Titanium Carbide (MXene) Composite Nanosheets For Near-infrared Iib (1530nm) Imaging-guided Photothermal Effects On Tumours

To date,the global trend of increasing cases and deaths from cancer(i.e.malignant tumours)has not been effectively halted,and cancer has become the second leading cause of death worldwide.Traditional cancer treatment methods such as surgery and chemotherapy are inadequate to deal with the increasing severity of the disease,and the search for more efficient and safe treatment methods has become a major concern.With the rapid development of nanomaterials technology,the potential of its application in the biomedical field is gradually being explored.Photothermal therapy,as a spin-off from the development of nanotechnology,is a potential alternative to cancer treatment.Photothermal therapy uses the selective tissue destruction of thermal energy,combining a light absorber with a wavelength-matched laser,and has the advantages of low risk,low side effects and high precision.As a new two-dimensional inorganic material,MXene,with its excellent hydrophilicity,electrical conductivity and unique mechanical properties,has greatly increased the diversity of applications for two-dimensional materials,but the rational design of MXene based composites and their typical applications in biomedicine remains a challenge.we have successfully constructed,for the first time,a 2D Ti₃C₂MXene nanosheets-based platform NaErF₄@Ti₃C₂for NIR-IIb/MR multimodal imaging-guided tumor hyperthermia.1.Firstly,we prepared Ti₃C₂small-size nanosheets with dimensions around 200nm by two-step etching,and completed the surface modification and functionalisation of the 2D Ti₃C₂MXene nanosheets using NaErF₄:0.5%Tm@Na Lu F₄(NaErF₄)core-shell nanoparticles,and the morphology and physicochemical properties of the constructed nanocomposites are also characterised by SEM,TEM,XRD and other characterisation methods.The in vitro photothermal conversion capability and photothermal stability of the Ti₃C₂@NaErF₄nanocomposites were initially investigated,and their potential applications in magnetic resonance(MR)imaging and NIR-IIb imaging are further explored.The results show that the synthesized Ti₃C₂@NaErF₄nanocomposites not only exhibit excellent in vitro photothermal conversion(43.62%under 808 nm laser irradiation)and photothermal stability,but also show good guiding ability for MR and NIR-IIb imaging.2.Next,we investigated the biocompatibility and therapeutic ability of Ti₃C₂@NaErF₄nanocomposites at the cellular and biological levels.Firstly,we evaluated the cytotoxicity of the composites using hepatoma cells Hep G2 as a model strain.The results showed that the composite exhibited low cytotoxicity under normal culture conditions,while it showed excellent photothermal conversion and strong cell killing effect under 808 nm laser irradiation induction.During the subsequent in vivo treatment,the composite material was enriched in the tumour tissue of mice through the EPR effect and induced by 808 nm NIR laser to rapidly warm up the tumour site,ultimately achieving ablation of the tumour.The tumour inhibition rate during the treatment was calculated to be 92.9%.In addition,the treatment did not affect the tissues and organs other than the tumours in mice when the tissue sections were stained and imaged after the treatment.Due to the highly efficient photothermal treatment capability and excellent biocompatibility of the Ti₃C₂@NaErF₄composites,we have completed the construction of an MR/NIR-IIb multimodal imaging-guided photothermal treatment platform based on Ti₃C₂@NaErF₄nanocomposites.