The Role of Surface Functionalization in the Design of PLGA Micro- and Nanoparticles

Abstract

Nano- and microcarriers prepared from the biocompatible and biodegradable polymer poly(D,L-lactide-co-glycolide) (PLGA) are being extensively studied for drug-delivery purposes. Apart from size, their fate in the body is mainly determined by surface characteristics that govern the interaction of the particles with their environment. The present review provides an overview of the currently established concepts for the surface functionalization of particles made from PLGA. In the first part, a concise description of the material-borne surface features and the related functionalization strategies are given, followed by current methods for the physical and chemical characterization of the particle surface. The second part highlights the aims of functionalization, which include improved drug delivery, vaccination, and imaging. Targeting approaches for site-specific delivery of drug-loaded particles to certain tissues or even to intracellular targets are presented, as well as stealth coatings for a prolonged blood circulation, labeling methods for imaging purposes, and strategies for the immobilization of macromolecular drugs on the particle surface. Finally, present limitations and future challenges will be discussed, with a focus on the surface-modification procedure and essential demands on functional particulate systems posed by the dynamic and complex in vivo environment.