A ratiometric fluorogenic nanoprobe for real-time quantitative monitoring of lysosomal pH

摘要

Lysosomes are known as key players in cellular signalling and act as terminal degradation stations involved in a multitude of cellular processes. Being a highly influential physiological factor, pH is essential in the regulation of lysosome-mediated physiological and pathological processes. Aberrant pH fluctuations are highly related to lysosomal dysfunction that correlates to lysosomal storage diseases and neurodegenerative disorders. As such, real-time quantitative monitoring of lysosomal pH (pH_L) is crucial for gaining insight into lysosomal dysfunction but challenging by the lack of effective lysosome-specific probes with high signal fidelity. Toward this end, we have proposed a lysosomal fluorogenic nanoprobe (TR-MP) for reliable ratiometric measuring of pH_L,. It is fabricated by rational manipulation of fluorescence resonance energy transfer (FRET) in a tailorable nanoplat-form. The nanoprobe consists of biocompatible silica nanoparticles assembled with a pH-sensitive rhodamine derivative (RDM-TEOS) as an acceptor and aggregation-induced emission (AIE) fluorophore (TPE-OMe) as a donor to ensure high energy transfer efficiency. Further equipped with cell-penetrating facilitator and mor-pholine to enable effective cell-internalization and high lysosome affinity of TR-MP. Results show that TR-MP can quantitatively measure pH in a range of 3.0 - 7.0 and detect pH_L fluctuations in live cells under various stimuli, as well as real-time monitor pH_L during apoptosis.