A team at IRIG is developing a technique called Dynamic Nuclear Polarization (DNP), which significantly increases the detection sensitivity of molecules by Nuclear Magnetic Resonance (NMR) spectroscopy. Its application to the grafting of a drug onto the surface of
cellulose nanofibers enabled detection of the drug itself and optimization of its anchoring process at grafting rates below the detection threshold of conventional characterization techniques.
Thanks to their developments in dynamic nuclear polarization, researchers at IRIG were able to push back the detection limit of their technique. Together with chemists from Grenoble's Department of Molecular Pharmacochemistry, they succeeded in optimizing the grafting by green chemistry of a prodrug onto the surface of cellulose nanofibers. Using DNP, different reaction and product washing conditions were tested to maximize the degree of grafting compared with simple adsorption, as well as the efficient elimination of by-products. They also demonstrated an unexpected reaction of cellulose with the grafted prodrug.
Figure: optimizing drug grafting onto cellulose nanofibers is like looking for a needle in a haystack. This magnifying glass is called nuclear magnetic resonance hyperpolarized by dynamic nuclear polarization. © miromiro/Getty Images
By providing a unique insight into surface species, the Dynamic Nuclear Polarization (DNP) technique may well become a key approach for the development of more robust green strategies for drug grafting onto cellulose nanofibers.
Cellulose nanofibers are used in a wide range of applications, including as controlled-release drug carrier. They combine the characteristics of wood, a natural, renewable, biocompatible and mechanically resistant material, with nanometric size and a large specific surface area.