IN VIVO MULTIPARAMETRIC QUANTUM NANOSENSING OF MENINGEAL MACROPHAGES USING NANODIAMOND SENSORS

Meningeal macrophages play an important role in immune surveillance and inflammatory responses at the brain–meningeal interface. Their functional states change dynamically in response to local microenvironmental cues; however, the direct in vivo measurement of intracellular parameters in these cells remains technically challenging.In this study, we have established an in vivo quantum nanosensing platform in order to measure the intracellular temperature and reactive radical signals in meningeal macrophages using nanodiamond-based quantum sensors.Fluorescent nanodiamonds containing nitrogen vacancy centers were successfully introduced into a mouse brain and stably internalized by meningeal macrophages. Using high-resolution in vivo optical imaging, we continuously monitored the quantum sensor signals from individual cells over repeated imaging sessions.The nanodiamond sensors enabled reliable multiparametric measurements of intracellular temperature and radical-related signals in living meningeal macrophages under physiological conditions. These measurements were stable over time, thus demonstrating that the quantum nanosensors could be maintained intracellularly without disrupting the cell viability or function. Under lipopolysaccharide-induced inflammatory conditions, changes in intracellular temperature and cell motility were observed in meningeal macrophages. Importantly, this approach allows simultaneous assessment of multiple intracellular parameters at the single-cell level in the intact brain.Our results have demonstrated the feasibility of in vivo multiparametric quantum nanosensing in brain-associated macrophages, and provide a new experimental framework for capturing complex functional changes in activated immune cells in their native environment.