Recent advances in polymeric biomaterials-based gene delivery for cartilage repair

Untreated articular cartilage damage normally results in osteoarthritis and even disability that affects millions of people.However,both the existing surgical treatment and tissue engineering approaches are unable to regenerate the original structures of articular cartilage durably,and new strategies for integrative cartilage repair are needed.Gene therapy provides local production of therapeutic factors,especially guided by biomaterials can minimize the diffusion and loss of the genes or gene complexes,achieve accurate spatiotemporally release of gene products,thus provideing long-term treatment for cartilage repair.The widespread application of gene therapy requires the development of safe and effective gene delivery vectors and supportive gene-activated matrices.Among them,polymeric biomaterials are particularly attractive due to their tunable physiochemical properties,as well as excellent adaptive performance.This paper reviews the recent advances in polymeric biomaterial-guided gene delivery for cartilage repair,with an emphasis on the important role of polymeric biomaterials in delivery systems.

Recent advances in biomaterials for 3D scaffolds: A review

Considering the advantages and disadvantages of biomaterials used for the production of 3D scaffolds for tissue engineering,new strategies for designing advanced functional biomimetic structures have been reviewed.We offer a comprehensive summary of recent trends in development of single-(metal,ceramics and polymers),composite-type and cell-laden scaffolds that in addition to mechanical support,promote simultaneous tissue growth,and deliver different molecules(growth factors,cytokines,bioactive ions,genes,drugs,antibiotics,etc.)or cells with therapeutic or facilitating regeneration effect.The paper briefly focuses on divers 3D bioprinting constructs and the challenges they face.Based on their application in hard and soft tissue engineering,in vitro and in vivo effects triggered by the structural and biological functionalized biomaterials are underlined.The authors discuss the future outlook for the development of bioactive scaffolds that could pave the way for their successful imposing in clinical therapy.

Micropatterned composite membrane guides oriented cell growth and vascularization for accelerating wound healing

Skin defect is common in daily life,but repairing large skin defects remains a challenge.Using biomaterials to deliver biochemical or physical factors to promote skin tissue regeneration is of great significance for accelerating wound healing.Specific surface micropatterns on biomaterials could affect cell behavior and tissue regeneration.However,few studies have focused on the construction of wound healing biomaterials with surface micropatterns and their role in skin tissue regeneration.In the present study,gelatin-polycaprolactone/silk fibroin composite membranes with different micropatterns were fabricated by photolithography,including line,grid and plane micropatterns.In vitro cell experiments demonstrated that the line micropattern on the composite membrane could guide cell-oriented growth,and more importantly,promote the expression of angiogenesis-related markers andα-smooth muscle actin(α-SMA)at both gene level and protein level.In the rat full-thickness skin defect model,the composite membrane with line micropatterns increasedα-SMA production and neovascularization in wounds,leading to accelerated wound contraction and healing.The current study not only suggests that composite membranes with specific micropatterns can be promising wound repair materials but also provides new insights into the importance of biomaterial surface topology for tissue regeneration.