Osteochondral tissue engineering: scaffolds, stem cells and applications

Abstract

Osteochondral tissue engineering has shown an increasing development to provide suitable strategies for the regeneration of damaged cartilage and underlying subchondral bone tissue. For reasons of the limitation in the capacity of articular cartilage to self-repair, it is essential to develop approaches based on suitable scaffolds made of appropriate engineered biomaterials. The combination of biodegradable polymers and bioactive ceramics in a variety of composite structures is promising in this area, whereby the fabrication methods, associated cells and signalling factors determine the success of the strategies. The objective of this review is to present and discuss approaches being proposed in osteochondral tissue engineering, which are focused on the application of various materials forming bilayered composite scaffolds, including polymers and ceramics, discussing the variety of scaffold designs and fabrication methods being developed. Additionally, cell sources and biological protein incorporation methods are discussed, addressing their interaction with scaffolds and highlighting the potential for creating a new generation of bilayered composite scaffolds that can mimic the native interfacial tissue properties, and are able to adapt to the biological environment.

Recent Strategies in Osteochondral Substitutes Design: Towards the Mimicking of a Multifaceted Anatomical Unit from the Nano to the Macro Level

“…Different strategies have been proposed by several authors in the recent years [32][33][34]. Most of the procedures consist of producing the two layers separately and connecting them secondarily.…”

Current advances in solid free-form techniques for osteochondral tissue engineering

“…Osteochondral (OC) tissue engineering requires unique scaffolds with specific properties, which ideally promote individual growth of both cartilage and bone layers [1]. The OC defects are characterized by an injury in the cartilaginous region, as well as in the underlying subchondral bone, and are frequently related with mechanical instability of the joint.…”

“…Despite being weaker and softer materials, natural polymers have the advantage of being flexible, thus presenting the capability to adapt their shape to the required forms. In addition, natural materials usually contain specific molecular domains that can support and guide cells, enhancing the biological interaction between the scaffold and the host tissue [1]. As example, Oliveira et al [5] developed a hydroxyapatite/chitosan (HA/CS) bilayered scaffold by combining a sintering with a freeze-drying technique.…”

Composite scaffolds for osteochondral repair obtained by combination of additive manufacturing, leaching processes and hMSC-CM functionalization

“…The need of relevant gradients of properties for the promotion of osteochondral repair has led to the development of composite scaffolds using different approaches previously reviewed [27,28]. Typical methods for the manufacture of scaffolds with functional gradients of properties include: the use of embedded (nano ) fibers and textiles within polymeric matrixes [27,28,29], the combination of rigid lattice structures with cell carrying hydrogels [27,28,30], the use of multi layered constructs [31,32] (normally requiring adhesives within layers), and computer aided tissue engineering constructs [33]. Among the most promising approaches, towards stable and effective composite scaffolds, it is important to note the combination of: a) phase separation or leaching processes, normally for obtaining the soft chondral phase, with b) computer aided rapid prototyping technologies based on addi tive manufacturing, usually for manufacturing the rigid bony phase [34].…”