Smart Device for Biologically Enhanced Functional Regeneration of Osteo–Tendon Interface

The spontaneous healing of a tendon laceration results in the formation of scar tissue, which has lower functionality than the original tissue. Moreover, chronic non-healing tendon injuries frequently require surgical treatment. Several types of scaffolds have been developed using the tissue engineering approach, to complement surgical procedures and to enhance the healing process at the injured site. In this work, an electrospun hybrid tubular scaffold was designed to mimic tissue fibrous arrangement and extracellular matrix (ECM) composition, and to be extemporaneously loaded into the inner cavity with human platelet lysate (PL), with the aim of leading to complete post-surgery functional regeneration of the tissue for functional regeneration of the osteo–tendon interface. For this purpose, pullulan (P)/chitosan (CH) based polymer solutions were enriched with hydroxyapatite nanoparticles (HP) and electrospun. The nanofibers were collected vertically along the length of the scaffold to mimic the fascicle direction of the tendon tissue. The scaffold obtained showed tendon-like mechanical performance, depending on HP content and tube size. The PL proteins were able to cross the scaffold wall, and in vitro studies have demonstrated that tenocytes and osteoblasts are able to adhere to and proliferate onto the scaffold in the presence of PL; moreover, they were also able to produce either collagen or sialoproteins, respectively—important components of ECM. These results suggest that HP and PL have a synergic effect, endorsing PL-loaded HP-doped aligned tubular scaffolds as an effective strategy to support new tissue formation in tendon-to-bone interface regeneration.

The Effects Of Cell Cycle Synchronization On The Growth Potential Of Primary Articular Chondrocytes

Rapid production of cartilaginous extracellular matrix (ECM) is required for scale up of any articular cartilage tissue engineering approach. Although several different methods have been investigated to increase the rate of cartilaginous ECM synthesis (e.g. growth factor stimulation, mechanical loading, etc.), there is evidence to suggest that cell cycle synchronization increases rate of ECM deposition. The issue with primary articular chondrocytes (PACs) is that routine methods to synchronize cells within a particular phase of the cell cycle rely on the use of monolayer culture, which is known to elicit cellular de-differentiation. This required development of a novel method of synchronizing cells within the S phase of the cell cycle during cell isolation. The objective of this study was to test whether synchronizing PACs would improve deposition of cartilaginous ECM in a three-dimensional culture model. Findings suggested that cell cycle synchronization was a viable method of improving the rate of matrix deposition in PACs.

The Effects Of Cell Cycle Synchronization On The Growth Potential Of Primary Articular Chondrocytes

Rapid production of cartilaginous extracellular matrix (ECM) is required for scale up of any articular cartilage tissue engineering approach. Although several different methods have been investigated to increase the rate of cartilaginous ECM synthesis (e.g. growth factor stimulation, mechanical loading, etc.), there is evidence to suggest that cell cycle synchronization increases rate of ECM deposition. The issue with primary articular chondrocytes (PACs) is that routine methods to synchronize cells within a particular phase of the cell cycle rely on the use of monolayer culture, which is known to elicit cellular de-differentiation. This required development of a novel method of synchronizing cells within the S phase of the cell cycle during cell isolation. The objective of this study was to test whether synchronizing PACs would improve deposition of cartilaginous ECM in a three-dimensional culture model. Findings suggested that cell cycle synchronization was a viable method of improving the rate of matrix deposition in PACs.

Hard Dental Tissues Regeneration—Approaches and Challenges

With the development of the modern concept of tissue engineering approach and the discovery of the potential of stem cells in dentistry, the regeneration of hard dental tissues has become a reality and a priority of modern dentistry. The present review reports the recent advances on stem-cell based regeneration strategies for hard dental tissues and analyze the feasibility of stem cells and of growth factors in scaffolds-based or scaffold-free approaches in inducing the regeneration of either the whole tooth or only of its component structures.

TNF-α-Inhibition Improves the Biocompatibility of Porous Polyethylene Implants In Vivo

Background: To improve the biocompatibility of porous polyethylene (PPE) implants and expand their application range for reconstructive surgery in poorly vascularized environments, implants were coated with tumor necrosis factor α (TNFα) inhibitor Etanercept. While approved for systemic application, local application of the drug is a novel experimental approach. Microvascular and mechanical integration as well as parameters of inflammation were analyzed in vivo. Methods: PPE implants were coated with Etanercept and extracellular matrix (ECM) components prior to implantation into dorsal skinfold chambers of C57BL/6 mice. Fluorescence microscopy analyses of angiogenesis and local inflammatory response were thrice performed in vivo over a period of 14 days to assess tissue integration and biocompatibility. Uncoated implants and ECM-coated implants served as controls. Results: TNFα inhibition with Etanercept led to a reduced local inflammatory response: leukocyte-endothelial cell adherence was significantly lowered compared to both control groups (n = 6/group) on days 3 and 14, where the lowest values were reached: 3573.88 leukocytes/mm-2 ± 880.16 (uncoated implants) vs. 3939.09 mm-2 ± 623.34 (Matrigel only) vs. 637.98 mm-2 + 176.85 (Matrigel and Etanercept). Implant-coating with Matrigel alone and Matrigel and Etanercept led to significantly higher vessel densities 7 and 14 days vs. 3 days after implantation and compared to uncoated implants. Mechanical implant integration as measured by dynamic breaking strength did not differ after 14 days. Conclusion: Our data show a reduced local inflammatory response to PPE implants after immunomodulatory coating with Etanercept in vivo, suggesting improved biocompatibility. Application of this tissue engineering approach is therefore warranted in models of a compromised host environment.

Exploiting the role of nanoparticles for use in hydrogel-based bioprinting applications: concept, design, and recent advances

Three-dimensional (3D) bioprinting is an emerging tissue engineering approach that aims to develop cell or biomolecule-laden, complex polymeric scaffolds with high precision, using hydrogel-based “bioinks”. Hydrogels are water-swollen, highly crosslinked...