Reconstruction of the anisotropic structure and proper function of the knee meniscus remains an important challenge to overcome, because the complexity of the zonal tissue organization in the meniscus has important roles in load bearing and shock absorption. Current tissue engineering solutions for meniscus reconstruction have failed to achieve and maintain the proper function in vivo because they have generated homogeneous tissues, leading to long-term joint degeneration. To address this challenge, we applied biomechanical and biochemical stimuli to mesenchymal stem cells seeded into a biomimetic scaffold to induce spatial regulation of fibrochondrocyte differentiation, resulting in physiological anisotropy in the engineered meniscus. Using a customized dynamic tension-compression loading system in conjunction with two growth factors, we induced zonal, layer-specific expression of type I and type II collagens with similar structure and function to those present in the native meniscus tissue. Engineered meniscus demonstrated long-term chondroprotection of the knee joint in a rabbit model. This study simultaneously applied biomechanical, biochemical, and structural cues to achieve anisotropic reconstruction of the meniscus, demonstrating the utility of anisotropic engineered meniscus for long-term knee chondroprotection in vivo.

A conductive fibrous scaffold made of silk fibroin and graphene was developed using electrospinning technique. The 3% G/SF scaffolds showed improved electroactivity and mechanical properties. Moreover, they could support the cell growth in vitro.

Vascular regeneration is known to play an essential role in the repair of injured tissues mainly through accelerating the repair of vascular injury caused by vascular diseases, as well as the recovery of ischemic tissues. However, the clinical vascular regeneration is still challenging. Cell-based therapy is thought to be a promising strategy for vascular regeneration, since various cells have been identified to exert important influences on the process of vascular regeneration such as the enhanced endothelium formation on the surface of vascular grafts, and the induction of vessel-like network formation in the ischemic tissues. Here are a vast number of diverse cell-based strategies that have been extensively studied in vascular regeneration. These strategies can be further classified into three main categories, including cell transplantation, construction of tissue-engineered grafts, and surface modification of scaffolds. Cells used in these strategies mainly refer to terminally differentiated vascular cells, pluripotent stem cells, multipotent stem cells, and unipotent stem cells. The aim of this review is to summarize the reported research advances on the application of various cells for vascular regeneration, yielding insights into future clinical treatment for injured tissue/organ.

Demineralized bone matrix (DBM) has been widely used for bone regeneration due to its osteoinductivity and osteoconductivity. However, the use of DBM powder is limited due to the difficulties in handling, the tendency to migrate from graft sites and the lack of stability after surgery. In this study, a mechanically stable, salt-leached porous silk fibroin carrier was used to improve the handling properties of DBM powder and to support the attachment, proliferation and osteogenic differentiation of rat bone marrow derived mesenchymal stem cells (rBMSCs). The DBM-silk fibroin (DBM/SF) scaffolds were fabricated with different contents of DBM powder (0%, 10%, 20%, 40% and 80% DBM/SF scaffolds). It was found that the DBM/SF scaffolds could form a stable composite preventing the migration of DBM powder. Moreover, the microarchitecture and mechanical properties of the scaffolds were influenced by the DBM powder. rBMSCs were seeded on the DBM/SF scaffolds and cultured for 14 days. Cell proliferation assays and cell morphology observations indicated that 20% DBM/SF scaffolds exhibited good cell attachment and proliferation. In addition, compared with the other groups, the cellular function was more actively exhibited on 20% DBM/SF scaffolds, as evident by the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis for osteoblast-related gene markers (e.g. COL1A1, ALP and cbfa1), the immunocytochemical evaluations of osteoblast-related extracellular matrix components (e.g. COL1A1, OCN and ONN) and the ALP activities. All the data suggested that DBM powder could be delivered using a silk fibroin carrier with improved handling characteristics and that 20% DBM/SF scaffolds had great potential as osteogenesis promoting scaffolds for successful applications in bone regeneration. † Electronic supplementary information (ESI) available: Immunocytochemistry staining video (10Â objective) of rBMSCs cultured on 20% DBM/SF scaffolds for 7 (Video S1) and 14 days (Video S2). The confocal images were captured from the surface to a depth of 165 mm with increments of 3 mm. The videos were created by the 3D projections module of LAS AF to observe the 3D morphologies of the cellscaffold constructs. See

The scaffold component is a major barrier to the development of a clinically useful small-diameter tissue-engineered vascular graft. Scaffold requirements include matching the mechanical and structural properties with those of native vessels and optimizing the microenvironment for cell integration, adhesion, and growth. Trilayered sulfated silk fibroin graft was developed to mimic native tissue structure and function. Physical properties and cell studies were assessed to evaluate the viability of their usage in small-diameter tissue-engineered vascular grafts. Compared with previously fabricated silk fibroin vascular grafts, these trilayered grafts provided comparable water permeability, tensile strength, burst pressure, as well as suture retention strength, to saphenous veins for vascular grafts. In addition, the in vitro results showed good cytocompatibility of the trilayered grafts. These physical and cellular outcomes indicate potential utility of these trilayered sulfated silk fibroin grafts for small-diameter vascular grafts.

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