Tilted fiber grating with metal nanocoating for calmodulin detection

We proposed and experimentally demonstrated a metal coated tilted fiber grating (TFG) for calmodulin detection. The sensor was designed as a reflective probe type by depositing a gold mirror in the down-stream of the TFG. A 50-nmthick gold nanocoating was radio-frequency magnetron sputtered over the fiber surface of an 18° TFG, and the transient receptor potential channels were bond onto the metal surface for calmodulin detection. The experimental results demonstrated that our biosensor can detect calmodulin with concentration as low as 1 μM. This result was better than that obtained using the isothermal titration calorimetry method. In addition, with the use of a custom-designed microfluid system, the volume of sample solution required by our biosensor was only 20 μL. Our proposed sensor is simple to fabricate and easy to implement, and it can be used for rapid, label-free, and microliter-volume biomolecule detection