Dendrimer modified 8-channel screen-printed electrochemical array system for impedimetric detection of activated protein C

The 8-channel screen-printed electrochemical array system (MULTI-SPE8) was developed as an impedimetric aptasensor, and applied for monitoring the interaction between DNA aptamer (DNA-APT) and its cognate protein, human activated protein C (APC), which is the key enzyme of the protein C pathway. Poly(amidoamine) (PAMAM) dendrimer having 16 succinamic acid surface groups (generation 2, G2-PS) was utilized in order to modify the surface of each carbon-based working electrode in MULTI-SPE8, and accordingly, an enhanced sensor response was recorded. Amino linked DNA-APT was then immobilized onto the surface of G2-PS/MULTI-SPE8, and its interaction with APC was explored. After the optimization of the experimental conditions; such as G2-PS, DNA-APT and APC concentration, the selectivity of the electrochemical aptasensor array system was tested in the presence of numerous biomolecules: protein C (PC), thrombin (THR), bovine serum albumin (BSA), factor Va (FVa) and chromogenic substrate (KS) in buffer media, or in the artificial serum: fetal bovine serum (FBS). The dendrimer-modified aptasensor technology based on MULTI-SPE8 has several advantages, such as disposable, fast screening of analyte at eight channels in one batch with low cost per measurement and resulting in a sensitive and selective indirect method for the analysis of APC, with the detection limits of 1.81 mu g/mL (0.64 pmol in 20 mu L sample) in buffer solution and 0.02 mu g/mL (8.22 fmol in 20 mu L sample) in diluted FBS. (C) 2014 Elsevier B.V. All rights reserved.