Micro/Nanometer‐Structured Scaffolds for Regeneration of Both Cartilage and Subchondral Bone

Abstract

Treatment of osteochondral defects remains a great challenge in clinical practice because cartilage and subchondral bone possess significantly different physiological properties. In this study, the controlled surface micro/nanometer structure of bioactive scaffolds in a combination of biomaterial chemistry is harnessed to address this issue. Model bioactive biomaterials, bredigite (BRT) scaffolds, with controlled surface micro/nanostructure are successfully fabricated by combining 3D printing with a hydrothermal process. It is found that the growth of micro/nano–calcium phosphate crystals on the surface of BRT scaffolds notably enhances their compressive strength by healing the microcracks on the strut surface. The micro/nanostructured surface distinctly facilitates the spread and differentiation of chondrocytes by activating integrin αvb1 and α5b1 heterodimers, regulates cell morphology, and promotes osteogenic differentiation of rabbit bone marrow stromal cells (rBMSCs) through the synergetic effect of integrin α5b1 and RhoA, in which the microrod surface demonstrates the highest stimulatory effect on the differentiation of chondrocytes and rBMSCs. The in vivo study shows that the micro/nanostructured surface of the 3D printed scaffolds obviously promotes the regeneration of both cartilage and subchondral bone tissues. This study suggests that the construction of controlled micro/nanostructured surface in porous 3D scaffolds offers a smart strategy to induce bilineage bioactivities for osteochondral regeneration.

A Physiology-Inspired Multifactorial Toolbox in Soft-to-Hard Musculoskeletal Interface Tissue Engineering

“…scaffolds ( Figure 3B). Interestingly, tailoring the surface topography of scaffolds by increasing either the roughness or the use of nano-scaled matrices has been shown to allow a better cell adhesion to the matrix, followed by subsequent tenogenic, osteogenic, and chondrogenic commitment of stem cells when in contact with oriented groove materials or just by creating dense or fibrous topologies in scaffolds, respectively [10,18,[44][45][46][47].…”

“…Structured surfaces distinctly facilitated the spread and differentiation of chondrocytes, regulated cell morphology, and promoted osteogenic differentiation of rBMSCs (b,c). Reproduced, with permission, from [46]. (C) Surface modification by dual reverse click reactions producing a continuous and gradient biofunctionalization to control stem cell differentiation for tendon-to-bone regeneration.…”

Bioinspired Biomaterials with a Brick‐and‐Mortar Microstructure Combining Mechanical and Biological Performance

“…The structure of the materials had a great effect on the performance of materials such as hydrophilicity, biocompatibility, and mechanical performance . Similar to traditional freeze casting, bidirectional freezing could regulate the microstructure of lamellar bioceramics by controlling the ratio of bioceramic in freezing slurry.…”

3D Printing of Bioinspired Biomaterials for Tissue Regeneration

“…Osteochondral defect is considered a thorny problem in clinic. [128,129] The cartilages lack blood vessels for the transport of nutrients, leading to the limitation of the proliferation and differentiation of chondrocytes. The cartilages are integrated with the subchondral bones which could help to promote cartilage regeneration.…”

“…By imitating the bilayer structure of osteochondral defects, lots of scaffolds have been designed to achieve the simultaneous regeneration of bone and cartilage. [128,130,131] Gao et al designed the gradient hydrogel scaffolds to repair the osteochondral defects. [129] The bottom layer of the gradient scaffold contained bioceramic nanoparticles to enhance the bioactive bonding with the host bone tissue.…”