Resumo:
Polyhydroxybutyrate (PHB) is a polymer synthesized by microorganism under
nitrogen deficiency and has as main characteristic the biodegradability. Bioactive
glasses belong to special systems as SiO2-MgO-CaO-P2O5. A composite bioactive
glass/PHB has as main aim to help bone reparation and regeneration. This composite
can offers support to bone growth (PHB) maintaining the function of the damaged organ
while the bioactivity is provided by glass helping the formation of new bone. The glass
produced in the present work is named VH30 and belongs to the system SiO2-MgO CaO-P2O5. These composites were produced in two compositions: 30Bio/70PHB with
30% of reinforcement and 40Bio/60PHB with 40% of reinforcement. Bioactive glass
had the size and superficial area of the particles characterized by Coulter Counter and
B.E.T, respectively; and its phases characterized by X-Ray Diffraction (XRD).
Bioactive glass was submitted to in vitro test in Simulated Body Fluid with and without
albumin (SBFA and SBF, respectively) and had its morphology observed via Scanning
Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) coupled and
by Atomic Force Microscopy (AFM). The PHB was characterized by XRD and
Differential Scanning Calorimetry (DSC). Composites produced had the microhardness
Vickers measured and were characterized by XRD. These composites were also
undertook to in vitro studies with SBF and observed by SEM-EDS. The SBF solutions
that soaked the composites were analyzed by Inductively Coupled Plasma (ICP) to
evaluate the ionic changes. In vitro results of VH30 when it was immersed in SBFA
suggest a bioactivity presented a Ca-P layer formation; however when it was immersed
in SBF the Ca-P layer was also formed and detached. These results indicating an
albumin influence in the layer adhesion. Microhardness results of composites indicated
values of 24,291 ± 8,76 HV and 25,273 ± 10,82 HV to the composites Bio40/60PHB
and Bio30/70PHB, respectively. In vitro results of composites, when immersed in SBF,
suggests that both present bioactivity. Nevertheless, the formation of Ca-P layer was
faster to composite 30Bio/70PHB than Bio40/60PHB. The formation of Ca-P layer on
composites occurs by deposition of Ca and P ions from solution, according to ICP
results.
