pH-responsive persistent luminescence nanoprobes biosensor for autofluorescence-free determination of glucose level in human samples and fingerprint encryption

Glucose level is an important indicator of diabetes, and maintaining an appropriate physiological concentration of glucose is important for human health. However, traditional optical sensors are interfered by the interference of strong background autofluorescence and natural responsive luminescence, which severely limits their application in complex biological samples. Herein, as a novel glucose biosensing probe, green-emitting Zn₂GeO₄:Mn²⁺, Eu³⁺ (ZGME) persistent luminescence nanoparticles (PLNPs) with pH stimulus-responsive was prepared by a facile one-pot hydrothermal method. We also investigated the pH stimulus-responsive luminescence behaviour of ZGME over a range of pH values from 2.8 to 8.0. Taking advantage of the interesting property that ZGME photoluminescence intensity has a pH response, within an extraordinarily narrow pH range of 5.0–6.5 for highly selectivity and sensitive determination of glucose level in human samples by acid-responsive quenching and persistent luminescent performance. The detection results show high accuracy of the measured values of glucose in serum with a wide detection range (2.5 μg L⁻¹-10 mg L⁻¹) and low detection limit (0.5 μg L⁻¹). Finally, the pH-responsive persistent luminescence also makes ZGME promising for high-level fingerprint information encryption. Hence, the established pH stimulation-responsive PLNPs-based biosensing probe offers excellent performance with high selective, accuracy and signal-to-noise ratio for detection of glucose level in human samples.