Simultaneous colorimetric determination of acute myocardial infarction biomarkers by integrating self-assembled 3D gold nanovesicles into a multiple immunosorbent assay.

An improved enzyme-free immunosorbent assay is described for the simultaneous detection of the myocardial infarction biomarkers N-terminal pro B type natriuretic peptide (NT-proBNP), creatine kinase-MB (CK-MB), and cardiac muscle troponin T (cTnT). The assay integrates 3D gold nanovesicles (GNVs) and three allochroic agents (phenolphthalein, methyl red, bromothymol blue). The pH regulated allochroic agents were enwrapped in GNVs to acts as ultrasensitive nanoprobes. Loading can be controlled by adjusting the temperature to efficiently load and release the allochroic agents. This bare-eye multicolor assay has limits of detection of 70 pg·mL-1 for NT-proBNP, 910 pg·mL-1 for CK-MB, and 7.8 pg·mL-1 for cTnT. Other features include (a) a linear range that extends over a wide range and sometimes is better than conventional HRP-based immunoassays, and (b) a precision that is comparable to immunofluorescence assays as used in the clinical laboratory. Graphical abstract Schematic presentation of an improved enzyme-free immunosorbent assay (EFISA). It integrates 3D gold nano-vesicles (GNVs) and allochroic agents for the simultaneous detection of acute myocardial infarction (AMI) biomarkers (N-terminal prohormone of brain natriuretic peptide (NT-proBNP), kinase-muscle/brain test (CK-MB), and cardiac muscle troponin (cTnT)).