Enhanced electrochemical detection of cardiovascular biomarker proteins using biogenic nanoporous silica diatoms

The goal of our research is to demonstrate the feasibility of employing biogenic nanoporous silica as a key component in developing a biosensor platform for rapid label-free electrochemical detection of proteins from pure and commercial human serum samples with high sensitivity and selectivity. The biosensor platform consists of a silicon chip with an array of gold electrodes forming multiple sensor sites and works on the principle of electrochemical impedance spectroscopy. Each sensor site is overlaid with a biogenic nanoporous silica membrane that forms a high density of nanowells on top of each electrode. The biosensor performance was tested for C-reactive protein from phosphate buffered saline and human serum. The performance of the biogenic silica membrane biosensor was tested both in the presence and absence of electrophoretic immobilization. Significant enhancement in the sensitivity and selectivity was achieved with the biogenic silica biosensor for detecting C-reactive protein from both pure and human serum samples. Significant enhancements in the measured impedance signal was obtained with the application of electrophoretic immobilization The sensitivity of the biogenic silica biosensor is ~1 pg/mL and the linear dose response is observed over a large dynamic range from 1 pg/mL to 1 μg/mL.