Ultra-Sensitive Biosensor Based on Cell-Derived Nanovesicles for CB1 Receptor-Targeted Drug Development in a Live Cell-Free Platform

The endocannabinoid system, particularly the cannabinoid receptor 1 (CB1), is essential for regulating numerous physiological processes, including pain, mood, appetite, and neurodegeneration. Given its crucial role, CB1 has become a target for therapeutic interventions with significant potential for treating various disorders. However, conventional methods such as calcium imaging and patch-clamp can only detect drug concentrations in the nanomolar to micromolar range, highlighting the need to develop more sensitive drug screening methods. To address this issue, we developed an ultrasensitive biosensor based on cell-derived CB1 nanovesicles (CB1-NV) coupled with carbon nanotube (CNT)-printed electrodes. This ultrasensitive sensor can detect cannabinoid compounds at picomolar concentrations by converting receptor-mediated Ca²⁺ influx into measurable electrical signals. The sensor exhibits remarkable sensitivity in terms of detecting trace tetrahydrocannabinol amounts (approximately 0.001%) in hemp seed oil, which conventional methods fail to detect. Compared with conventional methods, the developed biosensor exhibited a 1000-fold improvement in sensitivity, offering a promising tool for high-throughput drug screening and therapeutic research. Additionally, the CB1-NV sensor utilizes cell-free vesicles to preserve the cellular environment. However, because live cells were not involved, there was no requirement to maintain cell viability during the measurement process.