A highly sensitive and selective diagnostic assay based on virus nanoparticles

Abstract

Early detection of the protein marker troponin I in patients with a higher risk of acute myocardial infarction can reduce the risk of death from heart attacks. Most troponin assays are currently based on the conventional enzyme linked immunosorbent assay and have detection limits in the nano- and picomolar range. Here, we show that by combining viral nanoparticles, which are engineered to have dual affinity for troponin antibodies and nickel, with three-dimensional nanostructures including nickel nanohairs, we can detect troponin levels in human serum samples that are six to seven orders of magnitude lower than those detectable using conventional enzyme linked immunosorbent assays. The viral nanoparticle helps to orient the antibodies for maximum capture of the troponin markers. High densities of antibodies on the surfaces of the nanoparticles and nanohairs lead to greater binding of the troponin markers, which significantly enhances detection sensitivities. The nickel nanohairs are re-useable and can reproducibly differentiate healthy serum from unhealthy ones. We expect other viral nanoparticles to form similar highly sensitive diagnostic assays for a variety of other protein markers.

High affinity peptides for the recognition of the heart disease biomarker troponin I identified using phage display

“…Most troponin I detection methods are based on the conventional ELISAs in combination with optical (Amritsar et al, 2006) or electrochemical methods (Chua et al, 2009). In a recent example, Park et al (2009) reported engineered viral 3-dimensional nanostructures that are re-useable and can be used for the detection troponin I at attomolar concentrations.…”

Polyelectrolyte multilayers-modified membrane filter for rapid immunoassay: protein condensation by centrifugal permeation

“…Thus far, however, it has only been possible to satisfy only two of these elements. 3,4 Disposable immunotests (qualitative and quantitative), such as enzyme-linked immunosorbent assay (ELISA), retain the gold standard for protein detection and quantification. However, long incubation times are required to reach complete antigen-antibody reactions due to the long diffusion times of the antigen molecules toward the antibody as the rate-limiting step in these systems, resulting in slow binding kinetics and compromised assay sensitivity and dynamic range.…”

Biosensors for health applications

“…CRP measurement rely mainly on immunosensing technologies with optical, electrochemical and acoustic transducers besides approaches to simultaneous analytes measurement (Albrecht et al, 2008;Heyduk et al, 2008;McBride & Cooper, 2008;Niotis et al, 2010;Qureshi et al, 2010a,b;Sheu et al, 2010;Zhou et al, 2010). Silva et al (2010) incorporated streptavidin polystyrene microspheres to the electrode surface of SPEs in order to increase the analytical response of the cardiac troponin T and Park et al (2009) used an assay based on virus nanoparticles for troponin I highly sensitive and selective diagnostic, a protein marker for a higher risk of acute myocardial infarction. Early and accurate diagnosis of cardiovascular disease is crucial to save many lives, especially for the patients suffering the heart attack.…”