title: Nanosensor electrical immunoassay for quantitative detection of NT-pro brain natriuretic peptide.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  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.affiliation: Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road., Richardson, TX 75080, USA.
authors.forename: Anjan
authors.initials: A
authors.lastname: Panneer Selvam
authors.forename: Shalini
authors.initials: S
authors.lastname: Prasad
mesh_terms: D000537:Aluminum Oxide; D015415:Biomarkers / Q000032:analysis; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D058608:Nanopores; D020097:Natriuretic Peptide, Brain / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D000537:Aluminum Oxide