Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Quantitative Galactose Colorimetric Competitive Assay Based on Galactose Dehydrogenase and Plasmonic Gold Nanostars

Tozivepi Aaron Munyayi
* ORCID logo ,
Danielle Wingrove Mulder
* ,
Engela Helena Conradie
* ,
Barend Christiaan Vorster
* ORCID logo
Version 1 : Received: 9 October 2023 / Approved: 10 October 2023 / Online: 10 October 2023 (08:51:28 CEST)

A peer-reviewed article of this Preprint also exists.

Munyayi, T.A.; Mulder, D.W.; Conradie, E.H.; Vorster, B.C. Quantitative Galactose Colorimetric Competitive Assay Based on Galactose Dehydrogenase and Plasmonic Gold Nanostars. Biosensors 2023, 13, 965. Munyayi, T.A.; Mulder, D.W.; Conradie, E.H.; Vorster, B.C. Quantitative Galactose Colorimetric Competitive Assay Based on Galactose Dehydrogenase and Plasmonic Gold Nanostars. Biosensors 2023, 13, 965.

Abstract

We describe a competitive colorimetric assay that enables rapid and sensitive detection of galactose and reduced nicotinamide adenine dinucleotide (NADH) via colorimetric readouts and demon-strates its usefulness for monitoring NAD+-driven enzymatic reactions. We present a sensitive plasmonic sensing approach for assessing galactose concentration and the presence of NADH using galactose dehydrogenase immobilized gold nanostars (AuNS-PVP-GalDH). The AuNS-PVP-GalDH assay remains turquoise blue in the absence of galactose and NADH; however, as galactose and NADH concentrations grow, the reaction well color changes to a characteristic red color in the presence of an alkaline environment and metal ions catalyst (detection solution). As a result, when galactose is sensed in the presence of H2O2, the colored response of the AuNS-PVP-GalDH assay transforms from turquoise blue to light pink, then to wine red in a con-centration-dependent manner discernible to the human eye. This competitive AuNS-PVP-GalDH assay could be a viable analytical tool for rapid and convenient galactose quantification in re-source-limited areas.

Keywords

Gold nanostars; Enzymatic; Immobilized; Plasmonic; Colorimetric; Detection solution

Subject

Chemistry and Materials Science, Biomaterials

Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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