Polymer-Integrated Fiber Parallel Fabry–Perot Cavity Sensor Based on Ti 3 C 2 T x MXene-Enhanced Photothermal Effect for Myoglobin Detection

Acute myocardial infarction (AMI) is one of the leading causes of death in most developing and developed countries worldwide. As an important biomarker for the early diagnosis of AMI, myoglobin (Mb) renders the development of rapid and accurate detection technologies for it of great research signifi-cance. This paper proposes a parallel optical fiber Fabry-Perot (FP) cavity biosensor using polydimethylsiloxane (PDMS) as the functional cavity and Ti3C2TxMXene as the sensitizing material. PDMS has an extremely high thermal expansion coefficient, enabling it to convert the thermal signal generated by Mb under 405 nm laser irradiation into a change in cavity length. Ti3C2TxMXene can enhance the adsorption capacity of the sensing tip for Mb molecules. Paralleling two FP cavities with similar structures but different cavity lengths creates a Vernier effect, which can amplify spectral drift. Experimental results show that the sensor achieves a sensitivity of 4.515 nm/(mg/L) in the concentration range of 0.0001–10 mg/L, with a limit of detection (LOD) of 4.429 ng/ml. The proposed sensor features high sensitivity, a wide detection range, and strong robustness, with a detection time as short as 15 seconds. It holds potential application value in the field of early and rapid diagnosis of acute myocardial infarction.