Construction Of Degradable Mesoporous Carbon-silica-based Nanoparticles For Bioapplication

Phototherapy,typically implemented in the forms of photothermal therapy(PTT)and photodynamic therapy(PDT),is a promising strategy for cancer therapy owing to its noninvasiveness and high selectivity.Many nanomaterials have been currently reported for dual-modality PTT and PDT.Among them,carbon nanomaterials have flourished for cancer therapy for decades due to their easy fabrication and high photothermal conversion efficiency.However,their practical applications on clinical bases still pose a challenge to address the dilemma of metabolism in vivo.Herein,we successfully designed and synthesized an enzyme-free degradable carbon-silica nanocomposite(denoted as CSN)based on the three-dimensional dendritic biodegradable mesoporous silica nanoparticle(MSN),which has specific advantages as follows:(1)CSN can be degraded into small nanoparticles of～5 nm in 16 days in both simulated body fluid(SBF)and simulated lysosomal fluid(SLF)after NIR light irradiation without the participation of enzymes.(2)CSN alone has photothermal/photodynamic performance,as well as photoacoustic(PA)imaging ability for imaging-guided dual-mode phototherapy to improve the therapeutic effect.(3)The intrinsic immunoadjuvant property of CSN can mature DCs and induce the generation of tumor-associated antigens after combination with NIR light to provoke the subsequent antitumor immune response in no need of additional exogenous antigen.Besides the cell line-derived xenograft model(4T1 tumor model),patient-derived xenograft(PDX)model as a more clinically relevant tumor model,was also established to assess the in vivo therapeutic effect of CSN.And tumor inhibition efficiencies of CSN were 93.2%in 4T1 tumor model and 92.5%in PDX tumor model,respectively.We believe this strategy would develop the way for the design of biodegradable nanomaterials and facilitate the further clinical translation of carbon-silica-based nanomaterials with immunoadjuvant property.