posted on 2020-03-10, 11:44authored byNicole
E. Pollok, Charlie Rabin, Charuksha T. Walgama, Leilani Smith, Ian Richards, Richard M. Crooks
In
this paper, we demonstrate an electrochemical method for detection
of the heart failure biomarker, N-terminal prohormone brain natriuretic
peptide (NT-proBNP). The approach is based on a paper electrode assembly
and a metalloimmunoassay; it is intended for eventual integration
into a home-use sensor. 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).
There are four important outcomes reported in this article. 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. Second, the assay
is selective in that it does not cross-react with other cardiac natriuretic
peptides. Third, the assay forms in undiluted human serum (though
the electrochemical analysis is carried out in buffer). Finally, and
most important, the assay is able to detect NT-proBNP at concentrations
between 0.58 and 2.33 nM. This performance approaches the critical
NT-proBNP concentration threshold often used by physicians for risk
stratification purposes: ∼0.116 nM.