Quantitative Measurement of Cardiac Markers in Undiluted Serum

Abstract

Two mycocardial infarction biomarkers, myoglobin (MG) and cardiac troponin I (cTnI), were quantified at biological levels and in undiluted serum without sample pretreatment using surface plasmon resonance (SPR) sensors. To achieve detection of biomarkers in undiluted serum (72 mg/mL total protein concentration), minimization of the nonspecific signal from the serum protein was achieved by immobilizing the antibody for the biomarkers on an N-hydroxysuccinimide activated 16-mercaptohexadecanoic acid self-assembled monolayer. This monolayer reduces the nonspecific signal from serum proteins in such a manner that short exposure of the sensor to serum prior to analysis prevents any further nonspecific adsorption during analysis. Thus, sensing of MG and cTnI was achieved on the basis of the difference between signals from the active sensor and a reference sensor that captured background interference. This resulted in direct measurement of these biomarkers in undiluted serum. Detection limits for both markers were below 1 ng/mL, which is below the threshold needed to detect myocardial infarction. Detecting biomarkers in the low ng/mL range without signal amplification in such a complex matrix as serum corresponds to a selectivity of 108. The root-mean-square-error (RMSE) of calibration was below 2 ng/mL.

An Electrochemical Biosensor Based on a Myoglobin-specific Binding Peptide for Early Diagnosis of Acute Myocardial Infarction

“…[3][4][5] Optical biosensors, including a sandwich immunoassay with secondary labeled antibodies, enzyme-linked immunosorbent assay (ELISA), fluorescence, and surface plasma resonance (SPR), have been used for the detection of cardiac markers, such as troponin I, myoglobin, c-reactive protein (CRP), and myeloperoxidase (MPO). [6][7][8][9][10] Driven by a clinical need for pointof-care diagnostics, next-generation biosensors with improved sensitivity and specificity have attracted increasing attention in recent years, leading to the development of peptide-based sensing approaches. 11 Peptides derived from phage display are attractive alternatives to biosensor probes.…”

A simple method for quantification of interferon-2b through surface plasmon resonance technique

“…SPR is used in various fields such as food analysis (Taylor et al, 2006), pharmaceutical (Hwang et al, 2005;Chavane et al, 2008), environmental monitoring (Matsumoto et al, 2005;Shankaran et al, 2006;Habauzit et al, 2008), medical diagnostics (Haes et al, 2005;Yang et al, 2005;Gobi et al, 2007;Masson et al, 2007) and others (Baird et al, 2002;Beseničar et al, 2006;Katsamba et al, 2006). Previously, SPR was used to know the binding partners and its relative interaction strength for IFNs (Takacs et al, 1999;Asokan et al, 2006;Schmeisser et al, 2007), immune response against IFN-β (Gibbs and Oger, 2008) and in one particular instance to quantify IFN-γ (Stigter et al, 2005).…”

“…Moreover, it suspends the ligand in the solution Rich and Myszka, 2007). Yet, the use of hydrogel also comes with the limitation of handling more complex crude substances due to non specific adsorption (Shankaran and Miura, 2007) and also due to increase in non specific adsorption with respect to time of usage (Masson et al, 2007). In some cases, non specific adsorption can be reduced by adding CM dextran sodium salt in the samples (Karlsson et al, 1993;Yang et al, 2005).…”

Detection of human proteins using arrayed imaging reflectometry

“…SPR has, in various configurations, been used as a tool to study protein biomarkers in complex solutions (Cui et al, 2003;Battaglia et al, 2005). Only recently has a group reported the detection of nanogramper-milliliter quantities of human proteins from undiluted serum (Masson et al, 2007). Although this work utilized a human protein spiked into pure bovine serum, this is clearly a significant step forward.…”