Aligned carbon nanotube containing scaffolds for neural tissue regeneration

Neuropathologies include the deterioration and damage of the nervous system,especially neurons present in the brain,spinal cord and peripheral nervous system.Damage or alternations in neurons makes their structure and functionality abnormal.Every year over 90,000 people get affected by neurodegenerative diseases in the USA.Among all the neurological pathologies,

Aligned 3D porous polyurethane scaffolds for biological anisotropic tissue regeneration

A green fabrication process(organic solvent-free)of artificial scaffolds is required in tissue engineering field.In this work,a series of aligned three-dimensional(3D)scaffolds are made from biodegradable waterborne polyurethane(PU)emulsion via directional freeze–drying method to ensure no organic byproducts.After optimizing the concentration of polymer in the emulsion and investigating different freezing temperatures,an aligned PUs scaffold(PU14)generated from 14wt%polymer content and processed at196C was selected based on the desired oriented porous structure(pore size of 32.569.3 lm,porosity of 92%)and balanced mechanical properties both in the horizontal direction(strength of 41.3 kPa,modulus of 72.3 kPa)and in the vertical direction(strength of 45.5 kPa,modulus of 139.3 kPa).The response of L929 cells and the regeneration of muscle tissue demonstrated that such pure material-based aligned 3D scaffold can facilitate the development of orientated cells and anisotropic tissue regeneration both in vitro and in vivo.Thus,these pure material-based scaffolds with ordered architecture have great potentials in tissue engineering for biological anisotropic tissue regeneration,such as muscle,nerve,spinal cord and so on.

Multifunctional Fibroblasts Enhanced via Thermal and Freeze-Drying Post-treatments of Aligned Electrospun Nanofiber Membranes

Parallel fibrous scaffolds play a critical role in controlling the morphology of cells to be more natural and biologically inspired.Among popular tissue engineering materials,poly(2-hydroxyethyl methacrylate)(pHEMA)has been widely investigated in conventional forms due to its biocompatibility,low toxicity,and hydrophilicity.However,the swelling of pHEMA in water remains a major concern.To address this issue,randomly oriented and aligned as-spun pHEMA nanofibrous scaffolds were first fabricated at speeds of 300 and 2000 rpm in this study,which were then post-treated using either a thermal or a freeze-drying method.In cell assays,human dermal fibroblasts(HDFs)adhered to the freeze-drying treated substrates at a significantly faster rate,whereas they had a higher cell growth rate on thermally-treated substrates.Results indicated that the structural properties of pHEMA nanofibrous scaffolds and subsequent cellular behaviors were largely dependent on post-treatment methods.Moreover,this study suggests that aligned pHEMA nanofibrous substrates tended to induce regular fibroblast orientation and unidirectionally oriented actin cytoskeletons over random pHEMA nanofibrous substrates.Such information has predictive power and provides insights into promising post-treatment methods for improving the properties of aligned pHEMA scaffolds for numerous tissue engineering applications.

N‑Cadherin‑Functionalized Nanofiber Hydrogel Facilitates Spinal Cord Injury Repair by Building a Favorable Niche for Neural Stem Cells

The inhospitable niche at the injury site after spinal cord injury(SCI)brings several challenges to neural stem cell(NSC)therapy,such as limited NSC retention and neuronal differentiation.Biomaterial-based stem cell transplantation has become a promising strategy for building a favorable niche to stem cells.Herein,an aligned fibrin nanofiber hydrogel modified with N-Cadherin-Fc(AFGN)was fabricated by electrospinning and biochemical conjugation to deliver NSCs for SCI repair.The AFGN hydrogel provides multimodal cues,including oriented nanofibrous topography,soft stiffness,and specific cell binding ligand,for directing NSC functions and nerve regeneration.The conjugated N-Cadherin-Fc recapitulated the homo-philic cell-cell interaction for NSCs’adhesion on AFGN and modulated cellular mechanosensing in response to AFGN for NSC differentiation.In addition,the AFGN hydrogel carrying exogenous NSCs was implanted in a rat 2 mm-long complete transected SCI model and significantly promoted the grafted NSCs retention,immunomodulation,neuronal differentiation,and in vivo integration with inherent neurons,thus finally achieved renascent neural relay formation and an encouraging locomotor functional recovery.Altogether,this study represents a valuable strategy for boosting NSC-based therapy in SCI regeneration by engineering an NSC-specific niche.