A bilayered tissue engineered in vitro model simulating the tooth periodontium

Due to the complexity of the structure of the tooth periodontium, regeneration of the full tooth attachment is not a trivial task. There is also a gap in models that can represent human tooth attachment in vitro and in vivo. Aim of the study: to develop a bilayered in vitro construct that simulates the tooth periodontium, for the purpose of tissue regeneration and investigation of physiologic and orthodontic loading. Methods: Two types of materials were used to develop this construct: Sol-Gel 60S10Mg scaffold (University of Erlangen) representing the hard tissue component of the and commercially available Geistlich Bio-Gide® collagen membrane representing the soft tissue component of the tooth attachment. Each scaffold was dynamically seeded with periodontal ligament cells. The seeded scaffolds were either cultured separately, or combined in a bilayered construct, for 2 weeks. Characterization of the individual scaffolds and the bilayered constructs included biological characterization: (cell viability, SEM imaging to confirm cell attachment and viability qRT-PCR expression for periodontium regeneration markers), and mechanical characterisation of scaffolds and constructs. Results: HPDLCs enjoyed a biocompatible 3D environment within the bi-layered construct components as demonstrated by live/dead images and LDH assay. Gene expression showed variation between individual scaffolds and constructs detached from the bilayer. Most genes showed a drop in expression in the construct except for markers of angiogenesis which showed their highest expression in Bio-Gide® detached constructs. Conclusion and clinical significance: the development of this model is important for physiologic simulation invitro and for tissue regeneration purposes of the tooth periodontium

Ozonation of three different fungal conidia associated with apple disease: Importance of spore surface and membrane phospholipid oxidation

Although ozone (O-3) is a well-known bactericide and fungicide, the required dose of ozone can depend significantly on the targeted pathogens. The present research evaluates the variation in sensibility to ozone of three fungal species from a single fungal group. The three fungal species selected,Venturia inaequalis,Botrytis cinerea, andNeofabreae alba, belong to the Ascomycota group and attack apples. The fungi were exposed to ozone by bubbling directly into the spore solutions (treatment period ranged from 0.5 to 4 min, ozone concentration in inlet gas ranged from 1 to 30 g/m(3)). The rates of germination were determined, and the level of peroxidation of the lipid membrane was quantified based on the malondialdehyde (MDA) production. The results indicate that ozone effectively reduces spore development and suggest that the fungi differ in sensitivity. To reduce by 50% the spore germination rate ofN. alba,B. cinerea, andV. inaequalisrequires ozone doses of 0.01, 0.03, and 0.07 mg/ml, respectively. Spore sensitivity seems to be directly linked to spore surface. For all the fungal species, the MDA level and the level of spore inactivation both increase with ozone dose, which confirms that ozone alters the cell membrane