Multifunctional polyethyleneimine for synthesis of core-shell nanostructures and electrochemiluminescent detection of three AMI biomarkers

Simplicity and stability of an analytical method are the key to practical applications. In order to achieve such a goal, a molecule with multifunction could be one of the strategies. In this work, the multifunctional characteristics of branched polyethylenemine (bPEI) were employed for verification of this hypothesis. Three types of amines in the bPEI can be used to synthesize core-shell nanostructures (bPEI@Au and SiO2@bPEI@Au) in a simple one-pot process within 1 h, and as coreactants with over 500-fold enhancement for electrochemiluminescent (ECL) detection. Based on the remarkable performance of bPEI, a label-free ECL immunosensor and its array with the same assembly strategy were constructed for the simple and rapid determination of three acute myocardial infarction (AMI) biomarkers: cardiac troponin I (cTnI), human-type fatty acid binding protein (hFABP) and copeptin. Both methods exhibited excellent stability and sensitivity with wide linear range and low limits of detection down to fg/mL level by the photomultiplier tube and pg/mL level by the electron-multiplying charge-coupled device.