Fabrication And Characterization Of A Novel Release-Controlling Composite Membrane Containing Bioactive Glass

Periodontitis can be referred to as “a periodontium-affecting oral disease,aggravating from gingivitis and ascribing to hosts' immune system's responding to periodontopathogens,leading to destruction of tooth-supporting structures”.A major consequence of chronic periodontitis is the formation of abnormal pockets and then the loss of teeth,which is the main reason for lost teeth in adults.Nowadays,the standard treatment is mechanical removal of plaque,followed by antibacterial drugs.However,systematic application of antibiotics calls for a higher dosage which brings about adverse side effects and may give rise to resistance.Thus locally applied antibacterial drugs,especially those release-controlling ones,are hot issues today.In this study,we were trying to find a drug delivery system to enable the bioactive glass,which entails no resistance,to inhibit the microbes in a certain span of time.By assessing its physical and biological characterizations,inspiration and guidance in pharmacy and clinical application can be obtained.Part ? Selection of the delivery systemObjective: To select a suitable material that can be served as vehicle in the bioactive glass delivery system.Methods: Hyaluronic acid(HA),chitosan(CS),poly(lactic-co-glycolic)acid(PLGA),polyethylene glycol(PEG)and monomethoxy(polyethylene glycol)-poly(lactide-co-glycolide)(m PEG-PLGA)were mixed with pristine BAG powder respectively to be fabricated into composite membranes.General appearance,homogeneity and their degradation time were observed and compared.The most appropriate one would be chosen for further studies.Results: General observation demonstrated that HA or PEG-20000 degraded too fast,while PLGA or m PEG-PLGA too slowly.The homogeneity and film-forming was not satisfying when PEG-1000 or CS is employed.When HA was mingled with PLGA,it showed reasonable degradation time and agreeable morphology.Conclusions: HA in combination with PLGA would be an ideal delivery system for bioactive glass in treatment for periodontitis.Part ? Physiochemical properties of the PLGA-HA-BAG composite membranesObjective: To evaluate the physiochemical properties of the composite films.Methods: Composite films that contained different amount of BAG powder were fabricated and their thickness measured.Scanning electron microscope(SEM)was employed to observe the surface structure,followed by element analysis by energy dispersive spectrometer(EDS).After immersion in PBS for 1,3,5,7 and 9 days,the ion concentration in the extract was mensurated and solid remains were weighed.Results: With the increase of BAG in the composite film,its thickness rose,density of BAG particles on the surface grew,the weight loss during the immersion ascended and the alkalinity in the extract went up.However,concentration of Na,Ca and P in the extract manifested a more complex tendency.Conclusions: Physiochemical properties of the PLGA-HA-BAG composite membranes matched what was required by clinical application of treatment forPart ? Antibacterial effects and cytotoxicity of PLGA-HA-BAG composite membraneObjective: To probe the antibacterial effects of the composite film on Porphyromonas gingivalis(P.g.)and Actinobacillus actinomycetemcomitans(A.a.)and to test whether it was adverse to human periodontal ligament fibroblast cells.Methods: Cultivated with extract from immersion of the film or pristine BAG powder(as a positive control),the viability of P.g.and A.a.was acquired with the MTT assay.Then the efficiency of antibacterial effect was compared.In the same way,human periodontal ligament fibroblast cells(HPLFC)were cultivated with extract of the film,the viability of cells was mirrored with a cell counting kit-8(CCK-8).Results: Compared with the same amount of bioactive glass,extract from the composite film showed better antibacterial effects in the later part of the test.However,films used in the research were not able to kill all the microbes.Extract from the films had no inhibitive effects on the human periodontal ligament fibroblast cells compared with the control group(P<0.05).Conclusions: The PLGA-HA-BAG composite membranes had longer inhibitive effects against P.g.and A.a.and they had no cytotoxicity to human periodontal ligament fibroblast cells.It was promising that the membrane would be a release-controlling and locally-applied treatment for periodontitis in the near future.