A rational design of a cancer-specific and lysosome-targeted fluorescence nanoprobe for glutathione imaging in living cells

Developing a versatile probe for targeting the lysosomes of specific cancer cells and subsequently detecting glutathione (GSH) levels is critical in disclosing the roles of GSH in the lysosomal oxidative stress of cancer cells. Herein, we demonstrate an efficient strategy for the preparation of a dual-targeting (both cancer cell- and lysosome-targeting) fluorescence nanoprobe (DTFN) that enables the imaging of GSH in the lysosomes of specific cancer cells. The nanoprobe (DTFN) is obtained by combining folic acid (FA)-modified photostable aggregation-induced emission dots with GSH-responsive manganese dioxide (MnO2) nanosheets via electrostatic interactions. DTFN has outstanding characteristics of good water dispersity, delightful photostability, shorter responsive time (similar to 5 min) and wide pH-response range. Intracellular experiments showed that the as-prepared DTFN could be preferentially internalized into a folate receptor (FR)-positive cancer cells via the FR-mediated endocytosis. Subsequently, with the aid of the positively charged amino moiety of the nanoprobe, DTFN can selectively accumulate in lysosomes and successfully achieve the real-time imaging of the lysosomal GSH levels in FR-positive cancer cells. This study highlights a strategy to design a versatile dual-targeting fluorescence probe for enhanced cancer imaging.