Resorbable PCEC/gelatin-bismuth doped bioglass-graphene oxide bilayer membranes for guided bone regeneration

摘要

Guided bone regeneration (GBR) is a therapeuticmodality applied prior to dental implant placement to increase bone density at the defect site or during placement for directing bone growth around implant. In this study, an asymmetric, bilayer structure was prepared by covalently bonding a dense polycaprolactone-polyethylene glycol-polycaprolactone (PCEC)membrane layer with a hydrogel layer composed of bismuth doped bioactive glass (BG, 45S5) and graphene oxide (GO) particles incorporated in gelatin. Structural and mechanical properties (surface morphology and chemistry, thickness, degradation rate and tensile strength ofGBRmembranes) were studied.Membranes had a 3Dstructure having almost 1mmthickness which is suitable for space filling. Highest tensile strength (TS) (1.71 ± 0.10 MPa, p < 0.001) was observed formembranes having the highest BGcontaining group (BG20) while lowest TS was observed (1.23 ± 0.11 MPa, p < 0.001) for BG8/GO2samples. Similarly, hydrolytic degradation of BG20 involving bilayer structureswas slower in phosphate buffered saline (PBS) (23% ± 5%in 4weeks) than other GBRmembraneswhile biodegraded at an equal rate in lipase (BG20 as 72% ± 3%, BG10 as 69% ± 1%,BG8/GO2as 71% ± 7%and BG2/GO8as 74% ± 8%). BG8/GO2, displayed lowest gelatin (GEL) release in PBS over 28 d period (175% ± 9%and 164% ± 10%mgGEL/gsample, p<0.001).However, all bilayermembranes displayed a similar rate of degradation in lipase solution and also had similar mineral deposition ability in simulated body fluid. Significantly higher cell proliferation (p < 0.001) and osteogenic differentiation (p < 0.001) ofhuman dental pulp stemcells were observed in BG20 andBG10membrane groups than all other groups.On the other hand,GOpresence decreased bothmechanical and osteoinductive properties compared to pureBGcounterparts. Collectively, amine introduced (aminolysis) synthetic dense PCEClayer was covalently bonded to composite hydrogel layer to obtain coherent bilayermembranes forGBR.