Fig. 1. Molecular structures of fluorescent molecule DPBF, phosphorescent dye PdTFPP, and functional polymer PSMA, as well as preparation schematic of organic nanoparticle transducer (oxygen-responsive DPP was prepared via reprecipitation method, and then glucose oxidase was modified onto the surface of DPP to prepare organic nanoparticle transducer DPP-GOx)

Fig. 2. Characterization of organic nanoparticle transducer. (a) UV-Vis absorption spectra of fluorescent molecule DPBF, phosphorescent dye PdTFPP, and luminescent nanoparticle DPP; (b) representative TEM image of luminescent nanoparticle DPP, where the scale bar represents 50 nm; (c) hydrodynamic diameter of luminescent nanoparticle DPP before and after biological coupling reaction; (d) zeta-potential of luminescent nanoparticle DPP before and after biological coupling reaction

Fig. 3. Spectroscopic characterization and biocompatibility of organic nanoparticle transducer DPP-GOx. (a) Emission spectra of organic nanoparticle transducer at different glucose concentrations (0－20 mmol/L); (b) phosphorescence intensity (at 672 nm) of organic nanoparticle transducer versus time under different glucose concentrations (0－20 mmol/L); (c) emission peak intensity ratio (I_{672 nm}/I_{490 nm}) of organic nanoparticle transducer as a function of glucose concentrations (0－20 mmol/L); (d) cell viability of MCF7 cells incubated with DPP with different concentrations for 24 h; (e) repeated luminescence intensity test of polyacrylamide hydrogel loaded with organic nanoparticle transducer in PBS and glucose solution (20 mmol/L); (f) normalized luminescence intensity of organic nanoparticle transducer incubated with H₂O₂ (20 mmol/L) under UV excitation for different time

Fig. 4. Intracellular glucose level detection based on organic nanoparticle transducer. (a) MCF-7 cells incubated without DPP-GOx transducer in sugar-free medium as the control group; (b) MCF-7 cells incubated with DPP-GOx transducer in sugar-free medium for 12 h; (c) MCF-7 cells incubated with DPP-GOx transducer in sugar-free medium supplemented with glucose solution

Fig. 5. In vivo glucose concentration monitoring by organic nanoparticle transducer DPP-GOx. (a) Luminescent images of mice implanted with DPP-GOx transducer after intraperitoneal injection of glucose solution; (b) luminescent intensity of implanted DPP-GOx transducer enhanced with the elevated blood glucose concentrations; (c) luminescent images of mice implanted with DPP-GOx transducer after intraperitoneal injection of PBS; (d) luminescent intensity of implanted DPP-GOx transducer and blood glucose concentration remain unchanged