Bioactive glasses (BGs) are being increasingly considered for biomedical applications. One convenient approach to utilize BGs in tissue engineering and drug delivery involves their combination with organic biomaterials in order to form composites with enhanced biocompatibility and biodegradability. In this work, mesoporous bioactive glass nanoparticles (MBGN) have been merged with polyhydroxyalkanoate microspheres with the purpose to develop drug carriers. The composite carriers (microspheres) were loaded with curcumin as a model drug. The toxicity and delivery rate of composite microspheres were tested in vitro, reaching a curcumin loading efficiency of over 90% and an improving of biocompatibility of different concentrations of MBGN due to its administrations through the composite. The composite microspheres were tested in terms of controlled release, biocompatibility and bioactivity. Our results demonstrate that the composite microspheres can be potentially used in biomedicine due to their dual effects: bioactivity (due to the presence of MBGN) and curcumin release capability.

In recent years, composite biomaterials have attracted attention for drug delivery applications due to the possibility of combining desired properties of their components. However, some functional characteristics, such as their drug release efficiency and likely side effects, are still unexplored. In this regard, controlled tuning of the drug release kinetic via the precise design of a composite particle system is still of high importance for many biomedical applications. This objective can be properly fulfilled through the combination of different biomaterials with unequal release rates, such as mesoporous bioactive glass nanoparticles (MBGN) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microspheres. In this work, MBGNs and PHBV-MBGN microspheres, both loaded with Astaxanthin (ASX), were synthesised and compared in terms of ASX release kinetic, ASX entrapment efficiency, and cell viability. Moreover, the correlation of the release kinetic to phytotherapeutic efficiency and side effects was established. Interestingly, there were significant differences between the ASX release kinetic of the developed systems, and cell viability differed accordingly after 72 h. Both particle carriers effectively delivered ASX, though the composite microspheres exhibited a more prolonged release profile with sustained cytocompatibility. The release behaviour could be fine-tuned by adjusting the MBGN content in the composite particles. Comparatively, the composite particles induced a different release effect, implying their potential for sustained drug delivery applications.

Superparamagnetic iron oxide nanoparticles have been developed for various biomedical applications for decades. In this work, lauric acid-coated SPION (SPION^LA) were incorporated into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) at different ratios to produce composite microspheres, which were evaluated for their properties, including potential cytotoxicity. Additionally, a phytotherapeutic extract, curcumin, was loaded into the resulting microspheres to develop magnetic drug delivery capsules. The results show a significant improvement in the cytocompatibility after 7 days of SPION^LA administrated in cells through the composite microspheres compared to pristine SPION^LA. The composite also exhibited prolonged cumulative release of curcumin in a simulated body fluid environment. The results confirmed the efficacy of the mixture of PHBV and curcumin in attenuating potential side effects due to direct administration of high initial amounts of SPION^LA while maintaining magnetic properties in the resulting composite. The results add evidence to the potential of these composite devices for targeted drug delivery applications.