Construction of a Convenient and Highly Sensitive Sensor for the Detection of Myo in Serum Based on ELI-SERS

Acute myocardial infarction (AMI) is one of the most common causes of sudden death in cardiovascular disease, and myoglobin (Myo) is the first protein to be released in the blood after the attack, which is an important biomarker for clinical detection of AMI. The "Golden Rescue Time" for acute myocardial infarction is to intervene within the first 30 min after the attack; therefore, a rapid and accurate Myo detection method is needed urgently. In this study, we designed a combined enzyme-linked immunosorbent assay (ELISA) technique with surface-enhanced Raman scattering (SERS) immunoassay (ELI-SERS), which integrates the small sample volume, ease of operation, and excellent linearity of ELISA while utilizing the SERS technique and selecting the molecule with the Raman signal (IR-808), which is in resonance with the excitation wavelength, for further signal enhancement. The sensitivity of the system was further improved by optimizing the key factors in the assay such as incubation time, particle concentration, and temperature. Compared with the sandwich-structured magnetic bead method, no collection and concentration steps are required, simplifying the operation and ultimately realizing a sensitivity of a 5.3 pg/mL antigen detectable in 6 min. In actual serum samples, we achieve 100% accuracy and sensitivity by adding blockers to exclude the effect of heterophilic antibodies in serum and to reduce false positives in blank samples. We also validated the hepatitis B surface antigen test, demonstrating the universality of our system. Overall, this study designed an ultrasensitive and convenient SERS sensor for the detection of Myo, which extends the practical application of SERS and also contributes methods for the detection of other biomarkers.