Multiplexed electrochemical immunosensor for label-free detection of cardiac markers using a carbon nanofiber array chip

•A 3 × 3 sensor array as multiplexed electrochemical immunosensor has been developed.•Label-free detection of three key cardiac biomarkers has been demonstrated using the multiplexed platform.•Excellent sensitivity, selectivity with no cross talk between the sensors in the array has been shown.

We present an electrochemical multianalyte or multiplexed immunosensor for simultaneous label free detection of cardiac markers panel, comprising of C-reactive protein, cardiac troponin-I and myoglobin. The multi-electrode biosensor chip contains nine identical but electrically isolated microelectrodes arranged in a 3 × 3 array configuration. Each electrode contains carbon nanofiber nanoelectrodes grown vertically using plasma enhanced chemical vapor deposition. A hydrophobic photoresist layer, lithographically etched on the chip, exposes the electrodes and helps to selectively immobilize the antibody probes for the three target cardiac biomarkers using carbodiimide chemistry. The real-time label free detection of the three cardiac markers from a mixture is demonstrated with high sensitivity and selectivity. Detection in complex protein mixtures in human blood serum does not show any false positives from non-specific protein adsorption. The results show that the present sensor can serve as a miniaturized, low cost lab-on-a-chip system for the detection of various biomarkers in healthcare, environmental monitoring and security applications.

Graphical abstract3 × 3 sensor array chip consisting of carbon nanofiber electrodes.Figure optionsDownload full-size imageDownload as PowerPoint slide