The biological properties of a composite made of polydimethylsiloxane matrix and two kinds of calcium phosphate nanoparticles (hydroxyapatite, beta tricalcium phosphate) were tested by means of in vitro and in vivo investigations. Chemical and phase analyses of the nanoparticles were performed. The effects of different volume fractions of nanoparticles were investigated. Human osteoblast-like cell cultures (MG 63) demonstrated that the addition of 5-15 vol.% of nanoparticles had a significantly positive effect on osteoblast viability, and that high concentration did not support cell proliferation. The highest rates of osteointegration in pig bone were attained for implants modified by 15 vol.% hydroxyapatite and more intensive formation of new bone tissue was observed. Our study indicates that hydroxyapatite probably better imitates the composition and structure of the mineral phase of real bone.Web of Science5549348

Scaffolds made of degradable polymers, such as collagen, polyesters or polysaccharides, are promising matrices for fabrication of bioartificial vascular grafts or patches. In this study, collagen isolated from porcine skin was processed into a gel, reinforced with collagen particles and with incorporated adipose tissue-derived stem cells (ASCs). The cell-material constructs were then incubated in a DMEM medium with 2% of FS (DMEM_part), with added polyvinylalcohol nanofibers (PVA_part sample), and for ASCs differentiation towards smooth muscle cells (SMCs), the medium was supplemented either with human platelet lysate released from PVA nanofibers (PVA_PL_part) or with TGF-β1 + BMP-4 (TGF + BMP_part). The constructs were further endothelialised with human umbilical vein endothelial cells (ECs). The immunofluorescence staining of alpha-actin and calponin, and von Willebrand factor, was performed. The proteins involved in cell differentiation, the extracellular matrix (ECM) proteins, and ECM remodelling proteins were evaluated by mass spectrometry on day 12 of culture. Mechanical properties of the gels with ASCs were measured via an unconfined compression test on day 5. Gels evinced limited planar shrinkage, but it was higher in endothelialised TGF + BMP_part gel. Both PVA_PL_part samples and TGF + BMP_part samples supported ASC growth and differentiation towards SMCs, but only PVA_PL_part supported homogeneous endothelialisation. Young modulus of elasticity increased in all samples compared to day 0, and PVA_PL_part gel evinced a slightly higher ratio of elastic energy. The results suggest that PVA_PL_part collagen construct has the highest potential to remodel into a functional vascular wall.