A Paper Strip-Based Photoinduced Electrogenerated Chemiluminescence Platform with CTF/PMo12 Heterojunction-Sensitive Glutamic Acid Detection

Glutamic acid (GA), a crucial neurotransmitter, plays a significant role in brain function, muscle health, and various neurological disorders. Elevated GA levels have been associated with conditions such as stroke, Parkinson's disease, epilepsy, and Alzheimer's disease. Accurate detection of GA levels is paramount for both diagnostic and research purposes. Herein, we develop a photoinduced electrogenerated chemiluminescence (PECL) test strip fiber paper coated with a covalent triazine framework (CTF)/H₃PMo₁₂O₄₀ polyoxometalate (PMo12) heterojunction. Under blue-light irradiation, photogenerated carriers were separated by an electric field, π-electron delocalization, and polarization, leaving holes on the surface of PMo12 to drive ECL reactions based on luminol oxidation, enabling the detection of GA. This detection resulted in a PECL signal, and fluorometry information, including RGB values, was captured by using a smartphone. The PECL platform enabled the sensitive detection of GA as a neurotransmitter within a linear range of 0.05-1.7 mM, with a low limit of detection (LOD) of 15 nM. The results validated the safety and feasibility of this approach to detect GA in biological samples with satisfactory selectivity against other molecules. The combination of PECL with a smartphone reader presents an exciting avenue for the development of test strips on-site for visual real-time monitoring. This integration offers a high-throughput approach suitable for applications in point-of-care testing and disease monitoring.