Fabrication of elastin-like polypeptide nanoparticles for drug delivery by electrospraying.

The development of environmentally responsive drug carriers requires new methods for assembling stimuli-responsive nanoparticulates. This communication describes a novel application of electrospray to construct bioresponsive peptide-based particulates, which can encapsulate drugs. These particles are composed from genetically engineered elastin-like polypeptides (ELPs), a biodegradable, biocompatible, and bioresponsive polymer. To generate nanoparticles (300-400 nm in diameter), ELPs and drugs are codissolved in organic solvent, accelerated across a voltage gradient, dried by evaporation during transit, and collected from a target surface. These findings indicate that particle diameter, polydispersity, and morphology are strong functions of the solvent concentration, spraying voltage, and polymer molecular weight. Surprisingly, the loading of drug at 20 w/w% did not influence particle morphology; furthermore, drug release from these particles correlated with the pH-dependent solubility of the parent ELPs. These studies suggest that electrospray is an efficient and flexible method for generating stimuli-responsive drug particles.