Label-free electrochemical immunosensor for ultrasensitive determination of cardiac troponin I based on porous fluffy-like AuPtPd trimetallic alloyed nanodendrites

Abstract

Enhancement in the signals of electrochemical immunosensors via advanced nanomaterials is beneficial for developing immunoassay of cardiac troponin I (cTnI) with high sensitivity and selectivity. By virtue of K3[Fe(CN)6] as a signal probe, an advanced label-free electrochemical immunosensor was fabricated for ultrasensitive detection of cTnI with trimetallic alloyed AuPtPd porous fluffy-like nanodendrites (AuPtPd FNDs), followed by assembly of the antibody (Ab). By virtue of the structural advantages, electronic effects and synergetic catalysis of the trimetals, such nanostructures showed large specific surface area to increase the loading of the cTnI Ab and amplify the electrochemical signals of the probe. The sensor displayed a wide linear range (0.01 ~ 100.0 ng mL−1) and a low detection limit (LOD = 3 pg mL−1) under the optimal conditions, which showed great potential for detecting cTnI in serum samples. Furthermore, this biosensor provides an effective detection platform for analysis of other cardiac markers in practical samples.