Ratiometric detection of enzyme turnover and flavin reduction using rare-earth upconverting phosphors

Abstract

Gd4O2S:Yb:Tm rare-earth upconversion phosphors have been utilised to monitor the redox behaviour of flavin mononucleotide and report on the turnover of a flavo-protein, (pentaerythritol tetranitrate reductase). The presence of two bands separated by over 300 nm in the UCP emission spectra allows ratiometric signalling of these processes with high sensitivity.

Lanthanide Nanoparticles: From Design toward Bioimaging and Therapy

“…Therefore, the quenching and restoration of the blue UCL at 475 nm could be used together with the NIR UCL at 800 nm as the internal reference to monitor the redox behavior of PETNR and thus obtain information on the biocatalytic reactions. 392 The monitoring of enzymatic redox reactions utilizing UCL has also been investigated by Hirsch et al With hexagonal NaYF 4 :Yb,Tm@NaYF 4 UCNPs as the resource of UV/blue UCL, the reaction of the coenzyme of Flavin adenine dinucleotide (FAD) and the cosubstrate of nicotinamide adenine dinucleotide (NADH) can be monitored by the …”

Expanding the Scope of Biomolecule Monitoring with Ratiometric Signaling from Rare‐Earth Upconverting Phosphors

“…In order to ensure the ability to translate our approach to differently derived upconversion systems, the UCPs used in this work were either microscale commercial phosphors or synthesized nanoscale particles. The commercial phosphors were donated by Phosphor Technology Ltd. (PTIR475 and PTIR545) and were the same systems used in our previous report …”

“…In order to expand on our previous reports and investigate the scope of our UC biosensor systems, it was necessary to expand to other biomolecules and UCPs. If our initial aims would also work with a variety of biomolecules then, ultimately, it would allow the development of a wide range of biosensors.…”

“…Simplified schematic showing biosensor design of our “on/off” reversible energy transfer between rare‐earth upconverting phosphors (UCPs) and biomolecules, in this case the interaction between a Tm III ‐doped UCP and flavoprotein (PETNR) . Graphic reproduced with permission of the authors © The Royal Society of Chemistry 2014.…”

Small Upconverting Fluorescent Nanoparticles for Biosensing and Bioimaging

“…Glucose oxidase utilizes oxygen as the external electron acceptor and liberates hydrogen peroxide whereas glucose dehydrogenase cannot utilize oxygen as an electron acceptor and instead transfers electrons to various natural and artifi cial electron acceptors. [ 76,77 ] Additionally, the cosubstrate NADH and coenzyme FAD were respectively applied to construct a glucose and alcohol biosensor. [ 73 ] Glucose dehydrogenase is also glucose specifi c, and is not dependent on oxygen but must work in tandem with cofactor NAD phosphate (P) [ 72 ] A FAD-oxidase-based glucose biosensor was developed by Barrio et al [ 74 ] It hinges on the differential optical absorption between FAD and FADH 2.…”