Abstract
Distinguishing a specific biomarker from a biofluid sample containing a large variety of proteins often requires the selective preconcentration of that particular biomarker to a detectable level for analysis. Low-cost, paper-based device is an emerging opportunity in diagnostics. In the present study, we report a novel Zinc oxide nanorods functionalized paper platform for the preconcentration of Myoglobin, a cardiac biomarker. Zinc oxide nanorods were grown on a Whatman filter paper no. 1 via the standard hydrothermal route. The growth of Zinc oxide nanorods on paper was confirmed by a combination of techniques consisting of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS,) scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) analysis. The Zinc oxide nanorods modified Whatman filter paper (ZnO-NRs/WFP) was further tested for use as a protein preconcentrator. Paper-based ELISA was performed for determination of pre-concentration of cardiac marker protein Myoglobin using the new ZnO-NRs/WFP platform. The ZnO-NRs/WFP could efficiently capture the biomarker even from a very dilute solution (Myoglobin < 50 nM). Our ELISA results show a threefold enhancement in protein capture with ZnO-NRs/WFP compared to unmodified Whatman filter paper, allowing accurate protein analysis and showing the diagnostic concept.
Highlights
Those for high adsorption specificity for the marker of interest
Grown Zinc Oxide nanorods (ZnO-NRs) on Whatman filter paper were characterized by a series of complementary techniques
Figure shows scanning electron micrographs of zinc oxide nanorods functionalized paper representing the growth pattern of the nanorods on paper fibers (Fig. 1a) and the cross-sectional scanning electron microscopy (SEM) micrograph indicating that the nanorods grew all through the paper with very good surface coverage (Fig. 1b)
Summary
The adsorbed protein is desorbed from the nanostructured paper into the solution by providing a step change in its pH, ionic strength or even temperature This approach provides a promising strategy to capture and detect very low concentration marker protein in biosamples. ZnO-nanostructures of different morphology could serve as sensor to elucidate anticancerous and virostatic mechanisms[36,37,38,39,40,41,42,43] One such protein preconcentrator based on silicon nanowires grown on a silicon dioxide wafer showed to efficiently preconcentrate and sense specific protein from whole blood sample[44]. We report for the first time a paper modified with metal oxide nanorods as an efficient protein preconcentrator platform to produce a low-cost and biodegradable sensor. While a few research groups have investigated P-ELISA as analytical technique for protein concentration determination[49,50,51], there is no report of ZnO-nanostructure modified paper engineered as preconcentrator for biosensor application
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