Coacervation of Elastin-Like Recombinamer Microgels

The investigation of the coacervation (self-aggregation) behavior of biomicrogels which can potentially be used as drug carriers is an important topic, because self-aggregation can not only cause loss of activity, but also toxicity and immunogenicity. To study this effect microgels from elastin-like recombinamer are synthesized using miniemulsion technique. The existence of coacervation for such microgels, at different concentrations and temperatures, is studied and proved by cryo-field emission scanning clectron microscopy (cryo-FESEM), cryo-transmission electron microscopy (cryo-TEM), and by a novel (1) H high-resolution magic angle sample spinning (HRMAS), nuclear magnetic resonance (NMR) spectroscopy, and relaxometry methods. The findings by (1) H HRMAS NMR spectroscopy and relaxometry show simultaneous processes of volume phase temperature transition and coacervation with different sensitivity for hydrophobic and hydrophilic amino acid side-chains in the microgel. The coacervation process is more evidential by the behavior of glycine α-CH2 , (1) H NMR peak as compared to the proline β-CH2 .