Porous Hydrogel-Encapsulated Photonic Barcodes for Multiplex Detection of Cardiovascular Biomarkers

Early detection of cardiac troponin I (cTnI), B-type natriuretic peptide (BNP), and myoglobin (Myo) is essential for the diagnosis of acute myocardial infarction (AMI) and heart failure (HF). We designed a porous hydrogel-encapsulated photonic crystal (PhC) barcode-based suspension array for multiple cardiovascular marker detection. The hybrid hydrogel was composed of polyethylene glycol diacrylate (PEGDA) and gelatin, resulting in a porous and hydrophilic scaffold which ensured stability of the PhC in aqueous solutions. The encapsulated PhC barcodes had stable diffraction peaks for the corresponding markers. Using a sandwich format, the proposed suspension array was used for simultaneous multiplex detection of cardiovascular biomarkers in a single tube. The immunoassay results we tested on cTnI, BNP, and Myo could be assayed in the ranges of 0.01 to 1000 ng/mL, 0.1 to 10 000 pg/mL, and 1 to 10 000 ng/mL with limits of detection of 0.009 ng/mL, 0.084 pg/mL, and 0.68 ng/mL at 3σ, respectively. This method also showed acceptable accuracy and repeated detection, and the results were consistent with the results of conventional clinical methods for detecting actual clinical samples. Therefore, suspension arrays based on hydrogel-encapsulated PhC barcodes are highly promising for AMI diagnosis.