Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur GraphSearch.
The cellular level of nicotinamide adenine dinucleotide (NAD(+)), through its different functions, affects cellular metabolism and signalling(1-3). A decrease in the NAD(+) content has been associated with various pathologies and physiological aging(4,5), while strategies to boost cellular NAD(+) levels have been shown to be effective against age-related diseases in many animal models(6). The link between decreased NAD(+) levels and numerous pathologies and physiological aging has triggered the need for a simple quantification method for NAD(+), ideally applicable at the point of care. Here, we introduce a bioluminescent biosensor for the rapid quantification of NAD(+) levels in biological samples, which can be used either in laboratories or at the point of care. The biosensor is a semisynthetic, light-emitting sensor protein that changes the colour of emitted light from blue to red on binding of NAD(+). This NAD(+)-dependent colour change enables the use of the biosensor in paper-based assays in which NAD(+) is quantified by measuring the colour of the emitted light by using either a simple digital camera or a plate reader. We used the approach to quantify NAD(+) levels in cell culture, tissue and blood samples, yielding results that agreed with those from standard testing methods. The same biosensor furthermore allows the quantification of NAD(+)-dependent enzymatic activities in blood samples, thus expanding its utility as a tool for point-of-care diagnostics.