Antibody-Oriented Engineering Enables Rapid and Ultrasensitive SERRS-Based Detection of Cardiac Troponin T for Acute Myocardial Infarction Diagnosis

Acute myocardial infarction (AMI) is a leading global cause of death with a sudden onset, which necessitates rapid and accurate diagnosis for effective treatment. However, existing detection methods for emergency scenarios (e.g., ambulances) suffer from limited sensitivity and high cost, hindering their widespread application. To address this unmet clinical need, we developed a rapid and highly sensitive immunoassay platform based on surface-enhanced resonance Raman scattering (SERRS) for the quantitative detection of cardiac troponin T (cTnT), the gold-standard biomarker for AMI. This platform exhibits several advances. First, an antibody-oriented engineering strategy combined with core-shell SERRS nanotag synthesis fully exposes the antibody Fab regions to improve antigen-binding efficiency while reducing the nanotag cost by up to 75%. Meanwhile, selection of the resonance Raman reporter IR-808, which matches the 785 nm laser excitation wavelength, significantly enhances the detection signal intensity and sensitivity. Integrating these advantages with the classic sandwich immunoassay structure, the assay achieves a remarkable limit of detection of 0.24 pg/mL within only 7 min. Furthermore, systematic optimization of the incubation buffer (including pH value, surfactants, and blocking agents) effectively minimizes nonspecific adsorption, enabling 100% accurate differentiation between cTnT-positive and negative human serum samples. Collectively, this sensitive, rapid, and cost-effective platform demonstrates great potential for AMI point-of-care testing and prognosis monitoring.