Anjan Panneer Selvam1, Shalini Prasad. 1. Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road., Richardson, TX 75080, USA.
Abstract
AIM: To demonstrate a label-free electrical immunoassay for profiling vascular biomarker N-terminal pro-brain natriuretic peptide (NT-proBNP) associated with improved cardiac risk prediction. MATERIALS & METHODS: A high-density nanowell-based electrical immunoassay has been designed by integrating nanoporous aluminum oxide onto printed circuit board chips for the detection of NT-proBNP. The concentration of the biomarker is quantitatively determined by measuring impedance changes to the electrical double layer within the nanowells using electrochemical impedance spectroscopy. Detection sensitivity in the fg/ml range was obtained due to spatial confinement of the target biomarkers in size-matched nanowells. RESULTS & DISCUSSION: Electrical immunoassay performance was determined for the detection of NT-proBNP in phosphate-buffered saline (PBS) and human serum (HS). The lower limit of detection for the sensor was observed to be 10 fg/ml in PBS and 500 fg/ml in HS. The upper limit of detection was observed to be 500 fg/ml in PBS and 500 ng/ml in HS. CONCLUSION: A label-free technique for detection of NT-proBNP at clinically relevant concentrations for evaluating cardiac risk is demonstrated. High sensitivity and specificity, robust detection and low volume (100 µl) per assay project the technology to be a successful competitor to traditional ELISA-based techniques.
AIM: To demonstrate a label-free electrical immunoassay for profiling vascular biomarker N-terminal pro-brain natriuretic peptide (NT-proBNP) associated with improved cardiac risk prediction. MATERIALS & METHODS: A high-density nanowell-based electrical immunoassay has been designed by integrating nanoporous aluminum oxide onto printed circuit board chips for the detection of NT-proBNP. The concentration of the biomarker is quantitatively determined by measuring impedance changes to the electrical double layer within the nanowells using electrochemical impedance spectroscopy. Detection sensitivity in the fg/ml range was obtained due to spatial confinement of the target biomarkers in size-matched nanowells. RESULTS & DISCUSSION: Electrical immunoassay performance was determined for the detection of NT-proBNP in phosphate-buffered saline (PBS) and human serum (HS). The lower limit of detection for the sensor was observed to be 10 fg/ml in PBS and 500 fg/ml in HS. The upper limit of detection was observed to be 500 fg/ml in PBS and 500 ng/ml in HS. CONCLUSION: A label-free technique for detection of NT-proBNP at clinically relevant concentrations for evaluating cardiac risk is demonstrated. High sensitivity and specificity, robust detection and low volume (100 µl) per assay project the technology to be a successful competitor to traditional ELISA-based techniques.
Authors: Nandhinee Radha Shanmugam; Anjan Panneer Selvam; Thomas W Barrett; Steven C Kazmierczak; Milin Nilesh Rana; Shalini Prasad Journal: Future Sci OA Date: 2015-11-01