| In this work,we presented the development of cost-effective dual sensitivity enhancement
in gold nanoparticle-based lateral flow test strip for detection of carcinoembryonic
antigen. On the one hand, we employed protein G as a host matrix for oriented
immobilization of antibodies within the nitrocellulose membrane. On the other hand,
we utilized gold enhancement approach to visualize the final signals effectively.
Primary examinations revealed that the smaller sized nanoparticles have greater
signal enhancement compared to bigger ones. So, mono-dispersed gold nanoparticles
with average diameters of 11.40 ± 1.40 nm were utilized as tags. The measurement
of fluorescent intensity of FITC-tagged secondary antibody attached to the polyclonal
antibody, in the presence/absence of protein G as a host matrix on microplate wells,
showed the successful oriented immobilization of antibodies via the host matrix. The
FESEM images confirmed the attachment and growth of nanoparticles within the
porous nitrocellulose membrane, after gold enhancement. Finally, under the optimized
conditions, the developed strip could quantify the standard values of target within
2-50 ng/mL range with a limit of detection of 0.35 ng/mL. This strategy enabled the
reduction of antibody consumption from a conventional amount of 0.6 μg/strip down
to 0.012 μg/strip. The serum samples containing carcinoembryonic antigen were also
successfully analyzed by the developed strip with a visual detection limit of 10 ng/mL,
which confirms favorable characteristics of the developed test strip for point-of-care
applications. |