Crimped nanofiber scaffold mimicking tendon-to-bone interface for fatty-infiltrated massive rotator cuff repair

Electrospun fibers,with proven ability to promote tissue regeneration,are widely being explored for rotator cuff repairing.However,without post treatment,the microstructure of the electrospun scaffold is vastly different from that of natural extracellular matrix(ECM).Moreover,during mechanical loading,the nanofibers slip that hampers the proliferation and differentiation of migrating stem cells.Here,electrospun nanofiber scaffolds,with crimped nanofibers and welded joints to biomimic the intricate natural microstructure of tendon-to-bone insertion,were prepared using poly(ester-urethane)urea and gelatin via electrospinning and double crosslinking by a multi-bonding network densification strategy.The crimped nanofiber scaffold(CNS)features bionic tensile stress and induces chondrogenic differentiation,laying credible basis for in vivo experimentation.After repairing a rabbit massive rotator cuff tear using a CNS for 3 months,the continuous translational tendon-to-bone interface was fully regenerated,and fatty infiltration was simultaneously inhibited.Instead of micro-CT,μCT was employed to visualize the integrity and intricateness of the three-dimensional microstructure of the CNS-induced-healed tendon-to-bone interface at an ultra-high resolution of less than 1μm.This study sheds light on the correlation between nanofiber post treatment and massive rotator cuff repair and provides a general strategy for crimped nanofiber preparation and tendon-to-bone interface imaging characterization.

Multifunctional bioactive core-shell electrospun membrane capable to terminate inflammatory cycle and promote angiogenesis in diabetic wound

Diabetic wound(DW)healing is a major clinical challenge due to multifactorial complications leading to prolonged inflammation.Electrospun nanofibrous(NF)membranes,due to special structural features,are promising biomaterials capable to promote DW healing through the delivery of active agents in a controlled manner.Herein,we report a multifunctional composite NF membrane loaded with ZnO nanoparticles(NP)and oregano essential oil(OEO),employing a new loading strategy,capable to sustainedly co-deliver bioactive agents.Physicochemical characterization revealed the successful fabrication of loaded nanofibers with strong in vitro anti-bacterial and anti-oxidant activities.Furthermore,in vivo wound healing confirmed the potential of bioactive NF membranes in epithelialization and granulation tissue formation.The angiogenesis was greatly prompted by the bioactive NF membranes through expression of vascular endothelial growth factor(VEGF).Moreover,the proposed NF membrane successfully terminated the inflammatory cycle by downregulating the pro-inflammatory cytokines interleukin6(IL-6)and matrix metalloproteinases-9(MMP-9).In vitro and in vivo studies revealed the proposed NF membrane is a promising dressing material for the healing of DW.

Electrospinning:An emerging technology to construct polymer-based nanofibrous scaffolds for diabetic wound healing

A chronic wound in diabetic patients is a major public health concern withsocioeconomic and clinical manifestations.The underlying medical condition of diabeticpatients deteriorates the wound through physiological,metabolic,molecular,and cellularpathologies.Consequently,a wound enters a vicious pathological inflammatory cycle.Many therapeutic approaches are in practice to manage diabetic wounds hence ensuringthe regeneration process.Polymer-based biomaterials have come up with hightherapeutic promises.Many efforts have been devoted,over the years,to build aneffective wound healing material using polymers.The electrospinning technique,although not new,has turned out to be one of the most effective strategies in buildingwound healing biomaterials due to the special structural advantages of electrospunnanofibers over the other formulations.In this review,careful integration of allelectrospinning approaches has been presented which will not only give an insight intothe current updates but also be helpful in the development of new therapeutic materialconsidering pathophysiological conditions of a diabetic wound.

Fabrication and characterization of Antheraea pernyi silk fibroin-blended P（LLA-CL） nanofibrous scaffolds for peripheral nerve tissue engineering

Electrospun nanofibers have gained widespreading interest for tissue engineering application. In the present study, ApF/P（LLA-CL） nanofibrous scaffolds were fabricated via electrospinning. The feasibility of the material as tissue engineering nerve scaffold was investigated in vitro. The average diameter increased with decreasing the blend ratio of ApF to P（LLA-CL）. Characterization of 13C NMR and FTIR clarified that there is no obvious chemical bond reaction between ApF and P（LLA-CL）. The tensile strength and elongation at break increased with the content increase of P（LLA-CL）. The surface hydrophilic property of nanofibrous scaffolds enhanced with the increased content of ApF. Cell viability studies with Schwann cells demonstrated that ApFIP（LLA-CL） blended nanofibrous scaffolds significantly promoted cell growth as compare to P（LLA-CL）, especially when the weight ratio of ApF to P（LLA-CL） was 25：75. The present work provides a basis for further studies of this novel nanofibrous material （ApF/P（LLA-CL）） in peripheral nerve tissue repair or regeneration.

A regeneration process-matching scaffold with appropriate dynamic mechanical properties and spatial adaptability for ligament reconstruction

Ligament regeneration is a complicated process that requires dynamic mechanical properties and allowable space to regulate collagen remodeling.Poor strength and limited space of currently available grafts hinder tissue regeneration,yielding a disappointing success rate in ligament reconstruction.Matching the scaffold retreat rate with the mechanical and spatial properties of the regeneration process remains challenging.Herein,a scaffold matching the regeneration process was designed via regulating the trajectories of fibers with different degradation rates to provide dynamic mechanical properties and spatial adaptability for collagen infiltration.This core-shell structured scaffold exhibited biomimetic fiber orientation,having tri-phasic mechanical behavior and excellent strength.Besides,by the sequential material degradation,the available space of the scaffold increased from day 6 and remained stable on day 24,consistent with the proliferation and deposition phase of the native ligament regeneration process.Furthermore,mature collagen infiltration and increased bone integration in vivo confirmed the promotion of tissue regeneration by the adaptive space,maintaining an excellent failure load of 67.65%of the native ligament at 16 weeks.This study proved the synergistic effects of dynamic strength and adaptive space.The scaffold matching the regeneration process is expected to open new approaches in ligament reconstruction.