No abstract

Diseases of periodontal tissues are a considerable clinical problem, connected with inflammatory processes and bone loss. The healing process often requires reconstruction of lost bone in the periodontal area. For that purpose, various membranes are used to prevent ingrowth of epithelium in the tissue defect and enhance bone regeneration. Currently-used membranes are mainly non-resorbable or are derived from animal tissues. Thus, there is an urgent need for non-animal-derived bioresorbable membranes with tuned resorption rates and porosity optimized for the circulation of body nutrients. We demonstrate membranes produced by the electrospinning of biodegradable polymers (PDLLA/PLGA) coated with nanohydroxyapatite (nHA). The nHA coating was made using two methods: sonocoating and electrospraying of nHA suspensions. In a simulated degradation study, for electrosprayed membranes, short-term calcium release was observed, followed by hydrolytic degradation. Sonocoating produced a well-adhering nHA layer with full coverage of the fibers. The layer slowed the polymer degradation and increased the membrane wettability. Due to gradual release of calcium ions the degradation-associated acidity of the polymer was neutralized. The sonocoated membranes exhibited good cellular metabolic activity responses against MG-63 and BJ cells. The collected results suggest their potential use in Guided Tissue Regeneration (GTR) and Guided Bone Regeneration (GBR) periodontal procedures.

In this contribution, a full 3D finite element model of electrospun networks is presented. The model explicitly accounts for the specific microstructure of these networks by generating representative volume elements through a particular fibre deposition method inspired by the process of network formation during electrospinning. The modelled fibre material and structural properties, such as different fibre shapes and distributions in diameter, can vary over a wide range, and mutual fibre contact is considered in addition to permanent cross-links. In addition to the homogenized mechanical response to macroscopic in-plane loads, the model provides access to structural information which can hardly be determined in experiments, such as fibre disposition and interconnectivity. In the present work, this asset is used to inform a recent 2.5D modelling approach (Zündel et al., 2017) and to validate inherent assumptions on network structure. The comparison between the responses of the two approaches reveals that for networks of high porosity, the reduced 2.5D model captures well the mechanical behaviour in plane stress load cases. At lower porosities though, the increasing out-of-plane orientation of fibre segments leads to effects that cannot be captured by planar approaches and necessitate a 3D approach.