Monodisperse microspheres from supramolecular complexing polylactides

Monodisperse biodegradable microspheres are excellent candidates to serve as vehicles for drug delivery, especially when they are responsive to external stimuli. In this work, such particles are prepared by a droplet-based microfluidic technique from supramolecular complexing polylactides. Both L- and D- polylactides carrying 2-ureido-4[1H]-pyrimidinone (UPy) end groups on their chain ends are synthesized and then used in a joint approach of microfluidics and solvent evaporation to fabricate stimuli-responsive PLA particles with controlled sizes of 40-60 mu m and monodisperse size distribution. Due to the ability of the enantiomeric polylactides to form stereocomplexes and due to the additional supramolecular UPy binding, the stability of the obtained microspheres is significantly enhanced and sensitive to pH in the acidic regime. To demonstrate the utility of these microparticles for pH-dependent controlled release, a fluorescent dye is encapsulated and its release profiles are shown. (C) 2015 Elsevier B.V. All rights reserved.