In vitro and in vivo studies on blends of isotactic and atactic poly (3-hydroxybutyrate) for development of a dura substitute material.
Blends of semicrystalline isotactic poly(3-hydroxybutyrate) (PHB) with amorphous atactic PHB (at-PHB) were prepared by solution-casting using 30%, 50% and 70% at-PHB, and were studied for medical applications. The mechanical properties of the blends including the elastic modulus and elongation at break are strongly affected by the blend composition. The elastic modulus decreases with increasing fraction of at-PHB in the blend from 3350 MPa in the case of PHB to 170 MPa of PHB/at-PHB (30/70). In contrast, the elongation at break increases from 2% in pure PHB up to 50% in the case of the blend with 70% at-PHB. The in vitro degradation is changed as well. The molecular weight of PHB/at-PHB (30/70) is reduced to 5% after 2 years storage in phosphate buffer compared to 35% for pure PHB stored at identical conditions. The in vitro cell vitality is slightly reduced depending on the composition. PHB/at-PHB blends with 30% and 50% at-PHB were selected as dura substitute in minipigs based on the results of the in vitro investigation and the mechanical testing. Patch films with a structured surface on one side were fabricated by a dipping-leaching method. Dura defects were clinically and histologically examined 3, 6, and 9 months after implantation, confirming defect closure, prevention of adhesions to brain tissue, and no signs of inflammation or malignant degeneration. The PHB-based patch materials fulfill the requirements which are necessary for a dura substitute.
Kunze
Carmen
C
Institute for Biomedical Engineering, University of Rostock, Ernst-Heydemann-Str. 6, D-18055 Rostock, Germany. carmen.kunze@h3c.de
Edgar Bernd
Hans
H
Androsch
René
R
Nischan
Claudia
C
Freier
Thomas
T
Kramer
Sven
S
Kramp
Burkhard
B
Schmitz
Klaus-Peter
KP
D020155:3-Hydroxybutyric Acid / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001698:Biomedical Engineering; D002448:Cell Adhesion; D002460:Cell Line; D004388:Dura Mater / Q000473:pathology / Q000601:surgery; D004548:Elasticity; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D008422:Materials Testing; D051379:Mice; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry*; D000091402:Prohibitins; D013314:Stress, Mechanical; D013552:Swine; D013696:Temperature; D013718:Tensile Strength
D001672:Biocompatible Materials; C000717328:PHB protein, human; D011108:Polymers; D000091402:Prohibitins; D020155:3-Hydroxybutyric Acid