Biodegradable microcapsules and particles based on lactic acid polymers
Biocompatible microcapsules are used in medicine and pharmacy for a long time. They are designed to protect the active material (drug) from the surrounding environment or vice versa. Besides the protection of drug and environment, controlled release of the drug plays an important role.
The biodegradable particles are also of interest as materials for innovative product engineering such as additive manufacturing (or 3D printing) for the applications in microsurgery. The generative manufacturing processes - such as Selective Laser Sintering (SLS) or Selective Laser Melting (SLM) - require accordingly adjusted materials. The layered structure of the molds requires the usage of powdered materials with certain specifications, which are often not readily available. Thus, before the processing step, the powders have to be sufficiently free-flowing; agglomeration of the polymeric particles should be restricted. Besides, the particles should preferably be of spherical shape and have a defined particle size range. The required particle size range is, in turn, dependent on the manufacturing process. To produce very compact sintered parts, SLS processes require particles with at least bimodal particle distribution. In this case, the smaller particles, being melted, fill in the cavities formed between the larger particles. In contrast to the SLS, for the SLM, the polymeric particles should be as monodisperse as possible with the average particle size around 50 µm. On the basis of our experience in the microencapsulation, there is a possibility to produce biocompatible (and biodegradable) lactic acid-based polymeric particles with the range of properties, required for this specific application. The existing solvent-based production method will be supplemented by an optimized melt-based method.