Photothermal Generation Of Hydrogen Sulfide From Nanocomposites And Its Biological Application

Endogenous hydrogen sulfide?H₂S?is a novel gas signaling molecule involved in the regulation of vascular tone,myocardial contraction,nerve conduction,insulin secretion and other physiological processes such as inflammation,Parkinson's disease,brain trauma,myocardial ischemia and reperfusion,cancer,etc.It plays an important role in the diagnosis and treatment of a series of diseases.However,the physiological role of H₂S is closely related to its concentration.At present,the intervention of exogenous H₂S mainly depends on the direct injection of H₂S donor,and it is difficult to precisely control over the H₂S release.It is critical to develop stimuli-controlled strategies for H₂S generation and release with high spatial and temporal accuracy such as to optimize the therapeutic effects of H₂S.Based on this,this thesis aims to develop a H₂S donor system capable of temporally and spatially controlled release of H₂S.By combining thermal labile H₂S donors and photothermal nanoparticles,near-infrared light?NIR?triggered H₂S release hydrogel and artificial cell were developed,which were further exploited for anti-inflammatory treatment and cell signal transmission,respectively.The specific research contents are as follows:1.NIR light controlled photothermal release of H₂S from nanocomposite hydrogel for anti-inflammation application.This chapter constructs a novel NIR-induced H₂S release nanocomposite hydrogel.The H₂S precursor polyethyleneimine-dithiocarbamic acid polymer?PEI-DTC?was assembled by electrostatic adsorption on photothermal particles of gold-silver alloy plasma sub-particles?Au@Ag-Au pNPs?,and then loaded into an agarose hydrogel.NIR illumination photothermally induces an increase in the temperature of the nanoparticles,which in turn promotes the thermal decomposition of the H₂S precursor and releases H₂S.The change in illumination time and power allows precise control of H₂S release temporally and spatially.The nanocomposite hydrogel was used for the treatment of rat toe inflammation.The recovery rate was 62.1%after 3.0 h treatment.The scheme uses photothermal nanoparticles as NIR absorption antenna to induce H₂S donor photothermal release of H₂S,and proposes a new method for H₂S photothermal controllable release,which provides a possibility for biomedical applications such as H₂S anti-inflammation.2.Light controls cell growth behavior mediated by artificial cell generated H₂S messenger.NIR light controlled photothermal release of H₂S from artificial cell as cellular signal for regulation of cell growth behavior.This chapter constructs NIR responsive artificial cells capable of H₂S release.The thermal labile H₂S donor glycine-dithiocarbamate?Gly-DTC?and photothermal nanoparticles Au@Ag-Au pNPs are simultaneously encapsulated in artificial cells assembled from polydimethyldiallyl ammonium chloride?PDDA?and adenosine triphosphate?ATP?.Under NIR illumination,photothermal effect triggered the release of H₂S from artificial cells.When artificial cells are incubated with natural cells,H₂S is transmitted from artificial cells to natural cells,which alleviate the oxidative damage of natural cells,and facilitated the cell survival rate increased by 18.8%.Here,artificial cells mediated the indirect response of natural cells to light,and expands the sensory ability of natural cells without changing the natural cellular genetic information.This work also provides a new biomimetic application venue for H₂S.