AAV biosensors combine the power of adeno-associated virus (AAV) gene delivery with genetically encoded fluorescent reporters to enable real-time visualization of molecular and cellular activity in living systems. By packaging biosensor genes into AAV vectors, these tools can be efficiently delivered to specific cell types, tissues, or brain regions with long-lasting and stable expression.

AAV biosensors allow researchers to monitor dynamic biological processes such as calcium signaling, neurotransmitter release, membrane voltage, metabolic activity, and intracellular second messengers in vivo and in vitro. Once expressed in target cells, biosensors convert physiological events into optical signals—typically changes in fluorescence intensity or color—that can be recorded using standard fluorescence or two-photon microscopy.

Because AAV vectors provide high transduction efficiency, low toxicity, and strong cell-type specificity through the use of tailored promoters and capsids, AAV biosensors are ideally suited for neuroscience and other complex biological systems. They enable precise mapping of neural circuits, functional interrogation of signaling pathways, and longitudinal tracking of cellular activity in behaving animals or disease models.