Functionalization of Silk Fibers by PDGF and Bioceramics for Bone Tissue Regeneration

Textile Design of an Intervertebral Disc Replacement Device from Silk Yarn

Low back pain is often due to degeneration of the intervertebral discs (IVD). It is one of the most common age- and work-related problems in today's society. Current treatments are not able to efficiently restore the full function of the IVD. Therefore, the aim of the present work was to reconstruct the two parts of the intervertebral disc-the annulus fibrosus (AF) and the nucleus pulposus (NP)-in such a way that the natural structural features were mimicked by a textile design. Silk was selected as the biomaterial for realization of a textile IVD because of its cytocompatibility, biodegradability, high strength, stiffness, and toughness, both in tension and compression. Therefore, an embroidered structure made of silk yarn was developed that reproduces the alternating fiber structure of +30° and -30° fiber orientation found in the AF and mimics its lamellar structure. The developed embroidered ribbons showed a tensile strength that corresponded to that of the natural AF. Fiber additive manufacturing with 1 mm silk staple fibers was used to replicate the fiber network of the NP and generate an open porous textile 3D structure that may serve as a reinforcement structure for the gel-like NP.

Polymeric and Composite Carriers of Protein and Non-Protein Biomolecules for Application in Bone Tissue Engineering

Conventional intake of drugs and active substances is most often based on oral intake of an appropriate dose to achieve the desired effect in the affected area or source of pain. In this case, controlling their distribution in the body is difficult, as the substance also reaches other tissues. This phenomenon results in the occurrence of side effects and the need to increase the concentration of the therapeutic substance to ensure it has the desired effect. The scientific field of tissue engineering proposes a solution to this problem, which creates the possibility of designing intelligent systems for delivering active substances precisely to the site of disease conversion. The following review discusses significant current research strategies as well as examples of polymeric and composite carriers for protein and non-protein biomolecules designed for bone tissue regeneration.

Toughening of Bioceramic Composites for Bone Regeneration

Bioceramics are widely considered as elective materials for the regeneration of bone tissue, due to their compositional mimicry with bone inorganic components. However, they are intrinsically brittle, which limits their capability to sustain multiple biomechanical loads, especially in the case of load-bearing bone districts. In the last decades, intense research has been dedicated to combining processes to enhance both the strength and toughness of bioceramics, leading to bioceramic composite scaffolds. This review summarizes the recent approaches to this purpose, particularly those addressed to limiting the propagation of cracks to prevent the sudden mechanical failure of bioceramic composites.

Vertical Guided Bone Augmentation Using Titanium Mesh Domes Coated with Natural Latex Extracted from Hevea brasiliensis

The subject of this work is the evaluation of the use of titanium mesh domes coated with latex extracted from Hevea brasiliensis to promote vertical guided bone augmentation (GBA), above the normal limits of the skeleton. Twenty-four New Zealand rabbits were used, in which a circular groove of eight millimeters in diameter and nine holes in the internal region reaching the medulla were made with a trephine drill, in the calvaria. The dome, four millimeters in height, was fixed above this defect. The animals were divided into four groups (N = 6). The first (control) received a titanium dome not covered by the periosteum, and the second received a titanium dome that was covered by the periosteum. For the third, a dome with a latex coating was used and was not covered by the periosteum, and for the fourth, a titanium dome with a latex coating was used and was covered by the periosteum. After 90 days, the animals were euthanized. Computerized tomography imaging demonstrated that vertical bone augmentation was achieved in the groups with titanium domes coated with latex. Microscopic evaluation showed that there were no differences between the control group and Group 2, or between Groups 3 and 4. The other comparisons showed statistically significant differences (p < 0.05, ANOVA-Tukey).