Nanosensor Quantifying Lysosomal Glycosidase Secretion from Single Living Cells

Secretory lysosomes serve as crucial regulatory effectors in immune cells, carrying out versatile functions related to both degradation and secretion. Disruption of their secretion processes can lead to immune imbalances, resulting in various health complications. However, current immunostaining-based methods hinder real-time and quantitative monitoring of lysosomal enzyme secretion while maintaining cell viability. Here, we developed a strategy combining artificial substrates and hybrid nanowire-nanopipette sensors to quantify the secretion of lysosomal glycosidases from single living macrophages. Glycosidase secretion was induced by frustrated phagocytosis of macrophages, and the glycosidases specifically recognized and hydrolyzed the corresponding artificial substrates ejected from the nanopipette to liberate electroactive aminophenol, which was subsequently detected by the nanowire electrode. This work provides, for the first time, an innovative and versatile methodology to monitor lysosomal enzyme secretion by quantitative assessment of glycosidase secreted from individual living macrophages, highlighting the dynamics of secretory lysosomes in maintaining immune homeostasis.