Emergence of Polymer Stereocomplexes for Biomedical Applications

Abstract

Polylactide (PLA) and poly(methyl methacrylate) (PMMA) constitute, already for several decades, the gold standards for various biomedical applications due to their biocompatibility/inertness. Moreover, they have an additional property: they can form stereocomplexes (SCs) that have a more compact crystalline structure than the individual components. As a result, polymer SCs display improved thermal and mechanical properties, as well as delayed drug release and biodegradation rate in the case of drug delivery systems and biomaterials based on PLA, which is of prime importance in the biomedical field. In this article, the potential of SCs for biomedical applications in the areas of drug delivery, tissue engineering, and nanostructured surfaces is highlighted.

Spontaneous formation of polylactide stereocomplex microspheres containing metal ions

“…Among numerous studies concerning DDS built from PLA there are also some studies related to DDS formed from a PLA stereocomplex which differ in mechanical stability, degradation rate and thus release profile from DDS composed of only one stereoisomer. Microparticles and nanoparticles prepared from a PLA stereocomplex have been mainly based on PLA copolymers with polyethylene glycol or other hydrophilic polymers which were able to form micelles in water . In these cases stereocomplexation was applied to achieve the stabilization effect of micelles.…”

Stereochemical Sequence Dictates Unimolecular Diblock Copolymer Assembly

“…3 In addition, mixtures of stereodefined polymers can in some cases form stereocomplexes with unique properties. 4 …”

Encapsulation of hydrophobic vitamins by polylactide stereocomplexation and their release study

“…In the case of high molecular weight PLA, the stereocomplex melting point is about 50 °C higher (230 °C) than that of the PLLA or PDLA homopolymers (180 °C), and the melting enthalpy value reported in the literature (reflecting polymer crystallinity) for 100% crystalline stereocomplex prepared from high molecular weight PLA is 142 J g −1 (145 J g −1 by other authors) whereas one of the reported melting enthalpies of PLLA homocrystallites is 93 J g −1 . The stabilization of PLA‐based micelles (PLA/poly(ethylene oxide) or PLA with other hydrophilic block copolymers) by the introduction of PLA stereocomplex into the micelle structure has been applied by many authors and this type of stereocomplex implementation dominates . Apart from micelles formed in a water medium, different solid (nano)microparticles based on PLLA and PDLA copolymers were also prepared by the application of such methods as solvent evaporation, precipitation, lowering solvent temperature or spray droplet atomization .…”