Thermo-sensitivity of hybrid nanogels for specific endogenous hydrogen sulfide detection and efficient flash chill treatment

摘要

Thermo-responsive nanogels, poly(NIPAM-AAM) were prepared by a facile method of free radical one-pot precipitation based on monomeric N-isopropylacrylamide (NIPAM). At the same time, surface carboxyl group-modified fluorescent conjugated polymer nanoparticles (PNPs(-COOH)) were immobilized in the nanogel networks by hydrogen bonding to show bright green photoluminescence and outstanding thermo-responsive properties with a typical two-phase Tai Chi structure. Poly(NIPAM-AAm)-PNPs(-COOH) displays a larger change of hydrodynamic diameter (D-h) and a reversible volume transition from similar to 150 nm at 40 degrees C to similar to 1.0 mu m at 4 degrees C. The change will cause apoptosis of cells to finish flash chill treatment. Meanwhile, the fluorescence of poly(NIPAM-AAm)-PNPs(-COOH) demonstrates reversible quenching and recovery with the expansion and collapse of the nanogel network induced by temperature changes. In addition, when adding Fe3+, the fluorescence of poly(NIPAM-AAm)-PNPs(-COOH) can be quenched due to the chelation between the PNPs(-COOH) and Fe3+ and then recovered in the presence of hydrogen sulfide because the chelate is broken; this was attributed to the stronger affinity between Fe3+ and S2-. Therefore, the fluorescence nanoplatform, Fe3+/poly(NIPAM-AAm)-PNPs(-COOH), was successfully used to detect endogenous hydrogen sulfide in living A549 cells.