Study on a Plasmonic Tilted Fiber Grating-Based Biosensor for Calmodulin Detection

Tilted fiber Bragg grating, which has the advantages of both fiber Bragg grating and long-period fiber grating, has been widely studied for sensing in many fields, especially in the field of biochemistry. Calmodulin, which has a wide distribution in eukaryotes, can regulate several enzymes such as adenylate cyclase and guanylate cyclase and mediates several cellular processes such as cell proliferation and cyclic nucleotide metabolism. The abnormal levels of calmodulin in the body will result in serious effects from metabolism to nerve growth and memory. Therefore, it is important to measure the calmodulin concentration in the body. In this work, we propose and experimentally demonstrate a plasmonic tilted fiber Bragg grating-based biosensor for calmodulin detection. The biosensor was made using an 18 degrees tilted fiber Bragg grating with a 50 nm-thick gold nanofilm coating the surface of the fiber, and transient receptor potential channels were bonded onto the surface of the gold nanofilm to serve as bio-detectors for calmodulin detection. Experimental results showed that the limit of detection using our biosensor was 0.44 nM. Furthermore, we also demonstrated that the interaction between calmodulin and transient receptor potential channels was quite weak without calcium in the solution, which agrees with the biology. Our proposed biosensor has a simple structure, is easy to manufacture, and is of small size, making it a good choice for real-time, label-free, and microliter-volume biomolecule detection.

Automated summary

The tilted fiber Bragg grating combines the advantages of fiber Bragg grating and long-period fiber grating, and has been widely studied for sensing applications in fields such as biochemistry. Calmodulin, a protein widely distributed in eukaryotes, plays a crucial role in regulating enzyme activities and cellular processes. Researchers have developed a plasmonic tilted fiber Bragg grating-based biosensor for calmodulin detection, with a detection limit of 0.44 nM. The biosensor has a simple structure, is easy to manufacture, and is suitable for real-time, label-free, microliter-volume biomolecule detection.