Biogenic nanoporous silica-based sensor for enhanced electrochemical detection of cardiovascular biomarkers proteins.

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 cardiovascular biomarkers 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. When specific protein biomarkers: C-reactive protein (CRP) and myeloperoxidase (MPO) from a test sample bind to antibodies conjugated to the surface of the gold surface at the base of each nanowell, a perturbation of electrical double layer occurs resulting in a change in the impedance. The performance of the biogenic silica membrane biosensor was tested in comparison with nanoporous alumina membrane-based biosensor and plain metallic thin film biosensor. Significant enhancement in the sensitivity and selectivity was achieved with the biogenic silica biosensor, in comparison to the other two, for detecting the two protein biomarkers from both pure and commercial human serum samples. The sensitivity of the biogenic silica biosensor is approximately 1 pg/ml and the linear dose response is observed over a large dynamic range from 1 pg/ml to 1 microg/ml. Based on its performance metrics, the biogenic silica biosensor has excellent potential for development as a point of care handheld electronic biosensor device for detection of protein biomarkers from clinical samples.

Nanostructured surfaces for enhanced protein detection toward clinical diagnostics.

"Label-free" biomolecule sensors for detection of inflammatory cardiovascular biomarker associated with vulnerable coronary vascular plaque rupture were designed and fabricated using micro- and nanotextured polystyrene (PS) polymer structures that functioned as sensing elements coupled with electronic measurement equipment. We demonstrated that scaling down the surface texturing from the micro- to the nanoscale enhances the amplitude of the measured detected signal strength. We believe that the nanoscale fiber morphology provides size-matched spaces for trapping and immobilizing the protein biomolecule, resulting in improved detection signal strength. We selected PS as the model system and demonstrated the detection of human serum C-reactive protein. We employed these findings in designing a platform "lab-on-a-chip" protein sensor. Comparative studies were performed on PS textured surfaces of two different surface features: a PS microsphere mat and an electrospun PS nanofiber matrix. FROM THE CLINICAL EDITOR: In this study, nanotechnology-based biosensors for vulnerable coronary vascular plaque rupture were designed and fabricated using micro- and nanotextured polystyrene polymer structures. The authors demonstrated that scaling down the surface texturing from the micro- to the nanoscale enhances the sensitivity of this detection method.