Ag2S nanoparticles as an emerging single-component theranostic agent

Last two decades,with the rapid changes and development of nanotechnology and biological materials,diverse multi-functional nanomaterials emerging,which offers a novel way to treat and diagnose diseases,and therefore spawned the new biomedical technology of theranostics,which integrates the treatment and diagnosis or monitoring of diseases into one.Ag2S as a bio-nanomaterial with low biotoxicity has attracted more and more attention due to its good photoluminescence properties and fluorescence imaging of small animals in the second near-infrared region(NIR-Ⅱ).Meanwhile,Ag2S has the ability to absorb near-infrared light strongly because of its local surface plasma resonance(LSPR)effect and had become a kind of photothermal conve rters with good photothermal conve rsion efficiency.More interestingly,both photothermal effect and fluorescence characteristics of Ag2S nanoparticles(NPs)are closely related to their particle sizes.However,the relationship between photothermal effect and fluorescence characteristics of Ag2S NPs and their sizes has not been reviewed so far.Herein,the synthesis methods and influencing factors of synthesize Ag2S NPs with different sizes were compared firstly,and then the photothermal effect and fluorescence characte ristics of Ag2S NPs with different sizes were summarized.Finally,the possibilities and challenges of using Ag2S NPs to construct theranostic agent were discussed in the end.