Highly Sensitive and Specific Detection of Myoglobin in the Urine Based on Enhanced Photothermal Effect

Acute myocardial infarction can be diagnosed by measurement of myoglobin concentration in urine. In this article, a label-free sensor is proposed based on the photothermal effect of biomolecules, which is used for the immediate detection of myoglobin concentration in urine. The sensor was fabricated by a tapered microfiber (TMF) coated with the ultraviolet-curable polymer (UVCP) that has a high thermo-optical coefficient. The photothermal signal of biomolecules is only related to their selective absorption, while the scattering and reflection losses do not generate the photothermal signal. Therefore, specific identification could be realized by detecting the photothermal signal of myoglobin biomolecules. The results showed that the UVCP could enhance the detection sensitivity of photothermal signal due to the high thermo-optic coefficient. The sensitivity of the device is −267.652 nm/(mg/mL) in the concentration range of 0.0001–0.10 mg/mL, the limit of detection (LOD) is 74.7 ng/mL, and the response time is only 30 s. It can meet the demand for detecting the myoglobin concentrations in the urine analysis of related diseases, which has potential applications in the early diagnosis and quantitative analysis of conditions.