An auxin–tyrosine derivative based biocompatible supergelator: a template for fabrication of nanoparticles for sustained release of model drugs

Abstract

Bioinspired self-assembling peptides serve as powerful building blocks in the manufacturing of nanomaterials with tailored features. Inspired by the supergelating ability of naphthyl-Phe-OH (hydrogelator I), we synthesized naphthyl-Tyr-OH (hydrogelator II) and naphthyl-Trp-OH (hydrogelator III) with the objective of exploring the propensities of the phenolic OH of Tyr and the NH of the indole for controlling the gelation process. However, our experimental investigation reveals that hydrogelator II, containing Tyr as the aromatic core, shows an excellent gelation ability. But the Trp analogue fails to do so under similar conditions. To validate our results we performed MD simulation in an aqueous environment which significantly justifies that hydrogelator II exhibits a better hydrogelation ability than hydrogelators I and III. The characterisation of hydrogelator II was then performed in detail using various analytical and microscopic techniques and its biocompatibility was tested using an MTT assay. To examine the potentiality of hydrogelator II in drug delivery we developed hydrogel nanoparticles (HNPs) using the concept of self-assembly entirely governed by an ecofriendly approach i.e. weak interactions (like H-bonding, π–π and hydrophobic interactions). Our hydrogel nanoparticles display good release kinetics of the model drugs 5-fluorouracil and curcumin from the hydrogel matrix depending on their chemical structure, molecular weight and hydrophobicity. Thus our research shows that the choice of the core residue has a profound impact on the self-assembly process and thus on the gelation properties. Moreover, nanoparticles generated from our novel biocompatible hydrogelator II hold promise for future drug delivery applications.