Optical Detection of Cellular Signals at Material Interfaces.

Cellular functions are dynamically regulated by electrical, chemical, and mechanical signals. Optical methods provide high spatial resolution and flexibility for detecting and understanding cellular signals, but most existing approaches rely on fluorescent reporters, which are often limited by photobleaching, phototoxicity, and potential perturbation of native cellular behaviors. In recent years, materials-based optical detection has emerged as a promising strategy, which transduces subtle cellular signals into measurable optical readouts without introducing fluorescent labels or the need for genetic modification. However, this field is still at a nascent stage, as many materials platforms are constrained by limited detection sensitivity, specificity, spatiotemporal resolution, and compatibility with different biological systems. Here, we discuss recent advances in optical methods for detecting cellular signals harnessing cell-material interfaces. In particular, we connect the structure-property relationships of polymers, liquid crystals, carbon-based materials, two-dimensional materials, quantum materials, and plasmonic metals to their optical detection mechanisms. We then summarize the applications of these materials in optical detection of bioelectric, biomechanical, and biochemical signals. We anticipate that this review will bridge materials science with cell biology, and guide the rational design of next-generation material-based optical detection platforms for minimally invasive, high-sensitivity interrogation of cellular signals.