In between molecules and self-assembled fibrillar networks: Highly stable nanogel particles from a low molecular weight hydrogelator

Abstract

The preparation of molecular, non-polymeric, nanogels from a low molecular weight hydrogelator is reported. Molecular nanogels are expected to overcome issues associated with the use of polymeric nanogels in biomedicine such as biodegradability, stimuli responsiveness, polydispersity, and batch-to-batch reproducibility. Nanogels formed by compound 1 were reproducibly prepared by sonication of a xerogel in PBS, with a total concentration of ca. 2 mM. Intensity averaged diameter of ca. 200 nm was determined by DLS. Electron microscopy (TEM and cryo-TEM) revealed spherical particles. Light scattering (SALS) indicates that water is the main component of the nanoparticles, being the concentration of 1 in the nanogels of ca. 3 mg/mL. These particles can be considered to constitute an intermediate state between free molecules and self-assembled fibrillar networks. The nanogels present excellent temporal and thermal stability and accessible hydrophobic domains, as demonstrated by the incorporation of the fluorescent dye Nile Red.