Els Vanderleyden

Affinity Study of Novel Gelatin Cell Carriers for Fibronectin

In the present work, the gelatin/fibronectin affinity was evaluated using SPR, QCM and radiolabelling. The results indicate that type A gelatin films possess a higher affinity for Fn compared to type B gelatin. This is due to a combined hydrophobic and electrostatic interaction between gelatin type A and Fn. In a second part, the affinity of Fn for porous gelatin scaffolds was evaluated. The scaffolds were prepared by a cryogenic treatment and subsequent freeze-drying yielding type I and type II scaffolds which possess different pore geometries/sizes. The results indicate that the Fn density on the scaffolds can be fine-tuned by varying the Fn concentration, the gelatin type (A vs. B), the pore size/geometry (type I vs. type II scaffolds).

Engineered (hep/pARG)2polyelectrolyte capsules for sustained release of bioactive TGF-β1

Spatial and temporal controlled delivery of growth factors which contribute to efficient repair upon tissue injury or failure remains a major challenge in tissue engineering. In this paper, we evaluated polyelectrolyte multilayer microcapsules to control spatiotemporal release of transforming growth factor-β1 (TGF-β1). Polyelectrolyte microcapsules were bio-specifically engineered to enhance their ability to bind growth factors. Myofibroblast differentiation and contraction demonstrated that the bioactivity of TGF-β1 was not altered upon encapsulation into polyelectrolyte multilayer microcapsules and subsequent incorporation into gelatin based hydrogels. Finally, polyelectrolyte microcapsules were incorporated within a synthetic tissue engineering cryogel scaffold composed of gelatin without affecting the cryogel morphology, cell population capacity or mechanical properties of the scaffold.

Engineered 3D microporous gelatin scaffolds to study cell migration

Here we present a facile method to fabricate microporous hydrogel scaffolds that can be functionalized with a chemokine gradient. These scaffolds allow studying cellular responses in a 3D environment.

Implantable (Bio)Polymer Coated Titanium Scaffolds: A Review

In the current review we aim to give an overview of the state of the art of the research on (bio)polymer functionalised titanium implants for bone tissue engineering applications. After a short introduction on bone tissue engineering and the requirements the applied materials have to meet, an extensive discussion on titanium in bone tissue engineering will be given. Starting with a short description of both the titanium bulk and surface properties, the requirement for surface modified titanium will be highlighted. The discussion will encompass inorganic and organic chemical modifications and a combination thereof with a focus on the organic modifications. Within the latter type of modification, physical adsorption, physical incorporation and covalent immobilisation will be compared. In the final part of the review an overview will be given of the fabrication and characterisation of three-dimensional titanium scaffolds.

Gelatin functionalised porous titanium alloy implants for orthopaedic applications.

In the present work, we studied the immobilisation of the biopolymer gelatin onto the surface of three dimensional (3D) regular Ti6Al4V porous implants to improve their surface bio-activity. The successful immobilisation of the gelatin coating was made possible by a polydopamine interlayer, a polymer coating inspired by the adhesive nature of mussels. The presence of both coatings was first optimised on two dimensional titanium (2D Ti) substrates and confirmed by different techniques including X-ray photelectron spectroscopy, contact angle measurements, atomic force microscopy and fluorescence microscopy. Results showed homogeneous coatings that are stable for at least 24h in phosphate buffer at 37°C. In a next step, the coating procedure was successfully transferred to 3D Ti6Al4V porous implants, which indicates the versatility of the applied coating procedure with regard to complex surface morphologies. Furthermore, the bio-activity of these stable gelatin coatings was enhanced by applying a third and final coating using the cell-attractive protein fibronectin. The reproducible immobilisation process allowed for a controlled biomolecule presentation to the surrounding tissue. This newly developed coating procedure outperformed the previously reported silanisation procedure for immobilising gelatin. In vitro cell adhesion and culture studies with human periosteum-derived cells showed that the investigated coatings did not compromise the biocompatible nature of Ti6Al4V porous implants, but no distinct biological differences between the coatings were found.

Polydopamine-Gelatin as Universal Cell-Interactive Coating for Methacrylate-Based Medical Device Packaging Materials: When Surface Chemistry Overrules Substrate Bulk Properties.

Despite its widespread application in the fields of ophthalmology, orthopedics, and dentistry and the stringent need for polymer packagings that induce in vivo tissue integration, the full potential of poly(methyl methacrylate) (PMMA) and its derivatives as medical device packaging material has not been explored yet. We therefore elaborated on the development of a universal coating for methacrylate-based materials that ideally should reveal cell-interactivity irrespective of the polymer substrate bulk properties. Within this perspective, the present work reports on the UV-induced synthesis of PMMA and its more flexible poly(ethylene glycol) (PEG)-based derivative (PMMAPEG) and its subsequent surface decoration using polydopamine (PDA) as well as PDA combined with gelatin B (Gel B). Successful application of both layers was confirmed by multiple surface characterization techniques. The cell interactivity of the materials was studied by performing live-dead assays and immunostainings of the cytoskeletal components of fibroblasts. It can be concluded that only the combination of PDA and Gel B yields materials possessing similar cell interactivities, irrespective of the physicochemical properties of the underlying substrate. The proposed coating outperforms both the PDA functionalized and the pristine polymer surfaces. A universal cell-interactive coating for methacrylate-based medical device packaging materials has thus been realized.