Fabrication, multi-scale characterization and in-vitro evaluation of porous hybrid bioactive glass polymer-coated scaffolds for bone tissue engineering.

Bioactive glass-based scaffolds are commonly used in bone tissue engineering due to their biocompatibility, mechanical strength and adequate porous structure. However, their hydrophobicity and brittleness limits their practical application. In this study, to improve nanomechanical properties of such scaffolds, pure bioactive hybrid glass and two bioactive hybrid glass-polymer coated composites were fabricated. A complementary micro and nanoscale characterization techniques (SEM, AFM, µCT, FTIR, compressive test, goniometer) were implemented for detailed description of architecture and physicochemical properties of hybrid bioactive glass-based scaffolds with emphasis on nano-mechanics. The final step was in-vitro evaluation of three dimensional macroporous structures. Our findings show that after polymer addition, architecture, topography and surface properties of the scaffolds were changed and promoted favoured behaviour of the cells.

Characterization and influence of hydroxyapatite nanopowders on living cells.

Nanomaterials, such as hydroxyapatite nanoparticles show a great promise for medical applications due to their unique properties at the nanoscale. However, there are concerns about the safety of using these materials in biological environments. Despite a great number of published studies of nanoobjects and their aggregates or agglomerates, the impact of their physicochemical properties (such as particle size, surface area, purity, details of structure and degree of agglomeration) on living cells is not yet fully understood. Significant differences in these properties, resulting from different manufacturing methods, are yet another problem to be taken into consideration. The aim of this work was to investigate the correlation between the properties of nanoscale hydroxyapatite from different synthesis methods and biological activity represented by the viability of four cell lines: A549, CHO, BEAS-2B and J774.1 to assess the influence of the nanoparticles on immune, reproductive and respiratory systems.

PLA short sub-micron fiber reinforcement of 3D bioprinted alginate constructs for cartilage regeneration.

In this study, we present an innovative strategy to reinforce 3D-printed hydrogel constructs for cartilage tissue engineering by formulating composite bioinks containing alginate and short sub-micron polylactide (PLA) fibers. We demonstrate that Young's modulus obtained for pristine alginate constructs (6.9 ± 1.7 kPa) can be increased threefold (up to 25.1 ± 3.8 kPa) with the addition of PLA short fibers. Furthermore, to assess the performance of such materials in cartilage tissue engineering, we loaded the bioinks with human chondrocytes and cultured in vitro the bioprinted constructs for up to 14 days. Live/dead assays at day 0, 3, 7 and 14 of in vitro culture showed that human chondrocytes were retained and highly viable (∼80%) within the 3D deposited hydrogel filaments, thus confirming that the fabricated composites materials represent a valid solution for tissue engineering applications. Finally, we show that the embedded chondrocytes during all the in vitro culture maintain a round morphology, a key parameter for a proper deposition of neocartilage extracellular matrix.