Design and Development
of a Field Applicable Gold
Nanosensor for the Detection of Luteinizing Hormone
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Abstract
In this paper, we describe a novel strategy for the fabrication
of a nanosensor for detecting luteinizing hormone (LH) of sheep using
a gold nanoparticle-peptide conjugate. A new peptide sequence “CDHPPLPDILFL”
(leutinizing hormone peptide, LHP) has been identified, using BLAST
and Clustal W analysis, to detect antibody of LH (sheep). LHP has
been synthesized and characterized, and their affinity toward anti-LH
was established using enzyme linked immunosorbant assay (ELISA) technique.
The thiol group in LHP directly binds with gold nanoparticles (AuNPs)
to yield AuNP-LHP construct. Detailed physicochemical analysis of
AuNP-LHP construct was determined using various analytical techniques.
Nanosensor using gold nanoparticle peptide conjugate was developed
on the basis of competitive binding of AuNP-LHP and LH toward anti-LH.
Nitrocellulose membrane, precoated with anti-LH, was soaked in the
mixture of AuNP-LHP and sample of analysis (LH). In the absence of
LH (sheep), anti-LH coated on the membrane binds with AuNP-LHP, leading
to a distinctive red color, while in the presence of LH, no color
appeared in the membrane due to the interaction of anti-LH with LH
thereby preventing the binding of AuNP-LHP with membrane bound anti-LH.
The sensor assay developed in this study can detect LH (sheep) up
to a minimal concentration of ∼50 ppm with a high degree of
reproducibility and selectivity. The gold-nanoparticle-peptide based
nanosensor would be a simple, portable, effective, and low cost technique
for infield applications