Metabolic analysis of living cells in vitro is central to understanding cellular physiology, disease mechanisms, and responses to treatments. Traditional methods for monitoring metabolism often rely on offline assays or sophisticated high-field instruments that are expensive and require large sample volumes.

NMR spectroscopy, with its unparalleled ability to differentiate chemical species noninvasively, has long promised rich insight into biochemical processes, but its inherently low sensitivity has limited its use in microscale contexts. This challenge is particularly acute in microfluidic platforms, where sample volumes are minimal and metabolic processes evolve dynamically.