24– 26 This is the motivation for the study presented here. 18– 23 Because of this variability, it would be desirable for HF patients to be able to monitor their HF status at home because this could reduce the likelihood of decompensation and hospitalization. It should be noted, however, that serum natriuretic peptide concentration values can vary greatly depending on comorbidities, race, disease severity, and the age of the patient. 15– 18 This threshold allows physicians to identify HF patients as being at a high or low risk of hospitalization or mortality. The critical NT-proBNP concentration threshold used by physicians for risk stratification purposes is 1000 pg/mL (116 pM). One of those reasons is that the circulation half-life of NT-proBNP in the body is six times longer than BNP (120 vs 20 min, respectively), making it a more desirable biomarker for HF. The biological function of NT-proBNP is unknown, but for a number of reasons, it is used as a proxy for BNP in clinical settings to track the progression and severity of heart failure (HF). 13 The overall effect of this cascade of events is to reduce cardiac output and central venous pressure.īecause they both originate from proBNP, BNP and NT-proBNP are initially present in equal concentrations in the body. 11, 12 The primary function of natriuretic peptides, such as BNP, ANP, and CNP, is to lower blood pressure by increasing natriuresis and diuresis (reducing excess salt and water retention), inhibit the production and action of vasoconstrictor peptides, and promote vascular relaxation. 10, 11 Stretching of these heart muscle cells results in secretion of proBNP, which is enzymatically cleaved into BNP and NT-proBNP before being released into the bloodstream. NT-proBNP is a peptide that is secreted by ventricular cardiomyocytes that are stretched as a consequence of cardiac volume overload. These findings represent a notable contribution to current efforts aimed at detecting NT-proBNP using a state-of-the-art system that is evolving toward home-use applications.
![john scida john scida](https://i.ytimg.com/vi/w5GyR48sTHU/hqdefault.jpg)
Finally, and most important, the assay is able to detect NT-proBNP at concentrations between 0.58 and 2.33 nM with an overall relative standard deviation of <15%. 1– 3 Third, detection of NT-proBNP is not impacted by matrix effects 4, 5 in which the sandwich assay forms in undiluted human serum prior to analysis. Second, the assay is selective in which there is no cross-reactivity with other cardiac natriuretic peptides, such as brain, atrial, and C-type natriuretic peptides (BNP, ANP, and CNP, respectively). First, the use of a heterobifunctional cross-linker (HBCL), instead of the more common physisorption technique, for the bioconjugation of monoclonal immunoglobulin G antibodies (Abs) to silver nanoparticle (AgNP) labels improves the limit of detection and reproducibility of the assay. There are four important outcomes of this study. Here, we report on the detection of the cardiac biomarker, N-terminal prohormone brain natriuretic peptide (NT-proBNP), using a metalloimmunoassay adapted to a paper based electrochemical sensor. This performance approaches the critical NT-proBNP concentration threshold often used by physicians for risk stratification purposes: ~0.116 nM. Finally, and most important, the assay is able to detect NT-proBNP at concentrations between 0.58 and 2.33 nM.
![john scida john scida](https://i.pinimg.com/originals/9a/8a/c2/9a8ac291894dd9dc6e1b13f98687c23a.jpg)
Third, the assay forms in undiluted human serum (though the electrochemical analysis is carried out in buffer). Second, the assay is selective in that it does not cross-react with other cardiac natriuretic peptides. First, compared to physisorption of the detection Abs on the AgNP labels, a 27-fold increase in signal is observed when a heterobifunctional cross-linker is used to facilitate this labeling.
![john scida john scida](http://message.axkickboxing.com/images/user_uploaded/vorg/generation_x_049.jpg)
There are four important outcomes reported in this article. Sensing of NT-proBNP relies on the formation of a sandwich immunoassay and electrochemical quantification of silver nanoparticle (AgNP) labels attached to the detection antibodies (Abs). The approach is based on a paper electrode assembly and a metalloimmunoassay it is intended for eventual integration into a home-use sensor.
![john scida john scida](https://1.bp.blogspot.com/-v73oIXA4QjM/X_J2Kwg0yoI/AAAAAAABT3M/hBNlxA7qsvYXnPks8491Hgyw0MShgoXjgCLcBGAsYHQ/w1200-h630-p-k-no-nu/1965%2BJackie%2BGrumley.jpg)
In this paper, we demonstrate an electrochemical method for detection of the heart failure biomarker, N-terminal prohormone brain natriuretic peptide (NT-proBNP).