Construction of CPs@MnO2-AgNPs as a multifunctional nanosensor for glutathione sensing and cancer theranostic

A multifunctional nanosensor of CPs@MnO2-AgNPs was constructed for sensitive and selective sensing GSH and cancer theranostic in this work. CPs@MnO2 nanocomposite was synthesized by capping MnO2 onto carbon nanoparticles through an in situ redox reaction under ultrasonication. AgNPs with fluorescence were obtained through a silver-mirror-like reaction using BSA as both template and reductant and further connected onto the surface of CPs@MnO2 through electrostatic interaction to construct CPs@MnO2-AgNPs nanocomposite. The fluorescence of AgNPs was effectively quenched by MnO2 through inner filter effect and static quenching effect and further recovered by GSH owing to the unique redox reaction between GSH and MnO2. Thereout, a novel fluorescent turn-on nanosensor was established for GSH sensing in vitro and in vivo. For GSH sensing, a satisfactory linear range of 0.8-80 μM with a detection limit of 0.55 μM were obtained under optimal conditions. Moreover, integrating the GSH-responsive fluorescence imaging capacity, photothermal activity of carbon nanoparticles and anticancer effect of AgNPs, the CPs@MnO2-AgNPs nanocomposite was successfully applied for the cancer theranositc. The fluorescent recognition of cancer was achieved by overexpressed GSH in cancer, meanwhile the photothermal therapy from CPs and chemotherapy from AgNPs jointly produced an enhanced therapeutic effect. This redox-responsive nanocomposite of CPs@MnO2-AgNPs improve the MnO2 nanomaterials-based applications in GSH sensing and cancer theranostic.