Bioactive fibrous scaffolds with programmable release of polypeptides regulate inflammation and extracellular matrix remodeling

Inflammation manipulation and extracellular matrix(ECM)remodeling for healthy tissue regeneration are critical requirements for tissue engineering scaffolds.To this end,the bioactive polycaprolactone(PCL)-based scaffolds are fabricated to release aprotinin and thymosinβ4(Tβ4)in a programmable manner.The core part of the fiber is composed of hyaluronic acid and Tβ4,and the shell is PCL,which is further coated with heparin/gelatin/aprotinin to enhance biocompatibility.The in vitro assay demonstrates that the controlled release of aprotinin prevents initial excessive inflammation.The subsequent release of Tβ4 after 3 days induces the transition of macrophages from M1 into M2 polarization.The manipulation of inflammatory response further controls the expression of transforming growth factor-βand fibroblast activation,which oversee the quantity and quality of ECM remodeling.In addition,the gradual degradation of the scaffold allows cells to proliferate within the platform.In vivo implant evaluation convinces that PCL-based scaffolds possess the high capability to control the inflammatory response and restore the ECM to normal conditions.Hence,our work paves a new way to develop tissue engineering scaffolds for inflammation manipulation and ECM remodeling with peptide-mediated reactions.

The concentration game: differential effects of bioactive signaling in 2D and3D culture

Traumatic injuries to the central nervous system,such as traumatic brain injury,spinal cord injury and stroke,have a high prevalence,enormous financial costs and lack clinical treatments that restore neurological function（Ma et al.,2014）These injuries trigger a series of secondary biochemical and cellular responses that ultimately lead to cellular death and themaintenance of an unsupportive extracellular matrix （ECM） for tissue regeneration （Silva et al., 2014）. Artificial ECM or scaf- folds represent a way to alter this unsupportive environment to improve the efficacy of stem cell therapies and enhance neural tissue regeneration （Figure 1）.

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.

The recent advances in scaffolds for integrated periodontal regeneration

The periodontium is an integrated,functional unit of multiple tissues surrounding and supporting the tooth,including but not limited to cementum(CM),periodontal ligament(PDL)and alveolar bone(AB).Periodontal tissues can be destructed by chronic periodontal disease,which can lead to tooth loss.In support of the treatment for periodontally diseased tooth,various biomaterials have been applied starting as a contact inhibition membrane in the guided tissue regeneration(GTR)that is the current gold standard in dental clinic.Recently,various biomaterials have been prepared in a form of tissue engineering scaffold to facilitate the regeneration of damaged periodontal tissues.From a physical substrate to support healing of a single type of periodontal tissue to multi-phase/bioactive scaffold system to guide an integrated regeneration of periodontium,technologies for scaffold fabrication have emerged in last years.This review covers the recent advancements in development of scaffolds designed for periodontal tissue regeneration and their efficacy tested in vitro and in vivo.Pros and Cons of different biomaterials and design parameters implemented for periodontal tissue regeneration are also discussed,including future perspectives.