Engraving the Surface of Electrospun Microfibers with Nanoscale Grooves Promotes the Outgrowth of Neurites and the Migration of Schwann Cells

Biomimetic multi-channel nerve conduits with micro/nanostructures for rapid nerve repair

Peripheral nervous system (PNS) injuries often lead to significant sensory and motor impairments. Traditional artificial nerve conduits, lacking anisotropic structures, have been associated with prolonged repair time and failures in nerve regeneration. This study aimed to address these challenges by developing a novel approach for rapid repair of peripheral nerve injuries (PNI). A 3D oriented fibers scaffold featuring distinct radial (RFs) and longitudinal (LFs) fibers orientations was engineered using coaxial electrospinning and gas directional foaming techniques. This scaffold was then integrated with a shape memory conduit to form a directional multi-channel nerve conduit with micro/nanostructures. The results revealed that the grooved surface of the fibers significantly improved cellular directional guidance, effectively facilitating the migration of SCs from the periphery towards the center and from the base to the apex of the scaffold. In a rat model with a 10 mm nerve defect, the ND-PLATMC/LF ND-PCL scaffold significantly enhanced nerve regeneration and motor function recovery within 4 weeks. These results suggest the potential of this innovative scaffold for efficient repair of the nerve injuries.

Electrowriting patterns and electric field harness directional cell migration for skin wound healing

Directional cell migration is a crucial step in wound healing, influenced by electrical and topographic stimulations. However, the underlying mechanism and the combined effects of these two factors on cell migration remain unclear. This study explores cell migration under various combinations of guided straight line (SL) spacing, conductivity, and the relative direction of electric field (EF) and SL. Electrowriting is employed to fabricate conductive (multiwalled carbon nanotube/polycaprolactone (PCL)) and nonconductive (PCL) SL, with narrow (50 μm) and wide (400 μm) spacing that controls the topographic stimulation strength. Results show that various combinations of electrical and topographic stimulation yield significantly distinct effects on cell migration direction and speed; cells migrate fastest with the most directivity in the case of conductive, narrow-spacing SL parallel to EF. A physical model based on intercellular interactions is developed to capture the underlying mechanism of cell migration under SL and EF stimulations, in agreement with experimental observations. In vivo skin wound healing assay further confirmed that the combination of EF (1 V cm-1) and parallelly aligned conductive fibers accelerated the wound healing process. This study presents a promising approach to direct cell migration and enhance wound healing by optimizing synergistic electrical and topographic stimulations.

pH-responsive, self-sculptured Mg/PLGA composite microfibers for accelerated revascularization and soft tissue regeneration

Biodegradable Mg/polymer composite fibers offer a promising therapeutic option for tissue injury because of bioactive Mg2+ and biomimetic microstructure. However, current studies are limited to the contribution of Mg2+ and the single microstructure. In this study, we designed Mg/poly (lactic-co-glycolic acid) (Mg/PLGA) composite microfibers that significantly enhanced angiogenesis and tissue regeneration synergistically by Mg2+ and self-sculptured microstructure, due to spontaneous in situ microphase separation in response to the weakly alkaline microenvironment. Our composite microfiber patch exhibited superior performance in the adhesion, spreading, and angiogenesis functions of human umbilical vein endothelial cells (HUVECs) due to the joint contribution of the hierarchically porous microstructure and Mg2+. Genomics and proteomics analyses revealed that the Mg/PLGA composite microfibers activated the cell focal adhesion and angiogenesis-related signaling pathways. Furthermore, the repair of typical soft tissue defects, including refractory urethral wounds and easily healed skin wounds, validated that our Mg/PLGA composite microfiber patch could provide favorable surface topography and ions microenvironment for tissue infiltration and accelerated revascularization. It could cause rapid urethral tissue regeneration and recovery of rabbit urethral function within 6 weeks and accelerate rat skin wound closure within 16 days. This work provides new insight into soft tissue regeneration through the bioactive alkaline substance/block copolymer composites interactions.

Beyond the limiting gap length: peripheral nerve regeneration through implantable nerve guidance conduits

Peripheral nerve damage results in the loss of sensorimotor and autonomic functions, which is a significant burden to patients. Furthermore, nerve injuries greater than the limiting gap length require surgical repair. Although autografts are the preferred clinical choice, their usage is impeded by their limited availability, dimensional mismatch, and the sacrifice of another functional donor nerve. Accordingly, nerve guidance conduits, which are tubular scaffolds engineered to provide a biomimetic environment for nerve regeneration, have emerged as alternatives to autografts. Consequently, a few nerve guidance conduits have received clinical approval for the repair of short-mid nerve gaps but failed to regenerate limiting gap damage, which represents the bottleneck of this technology. Thus, it is still necessary to optimize the morphology and constituent materials of conduits. This review summarizes the recent advances in nerve conduit technology. Several manufacturing techniques and conduit designs are discussed, with emphasis on the structural improvement of simple hollow tubes, additive manufacturing techniques, and decellularized grafts. The main objective of this review is to provide a critical overview of nerve guidance conduit technology to support regeneration in long nerve defects, promote future developments, and speed up its clinical translation as a reliable alternative to autografts.

Guiding the Path to Healing: CuO2 -Laden Nanocomposite Membrane for Diabetic Wound Treatment

Diabetic chronic wounds pose significant clinical challenges due to their characteristic features of impaired extracellular matrix (ECM) function, diminished angiogenesis, chronic inflammation, and increased susceptibility to infection. To tackle these challenges and provide a comprehensive therapeutic approach for diabetic wounds, the first coaxial electrospun nanocomposite membrane is developed that incorporates multifunctional copper peroxide nanoparticles (n-CuO2 ). The membrane's nanofiber possesses a unique "core/sheath" structure consisting of n-CuO2 +PVP (Polyvinylpyrrolidone)/PCL (Polycaprolactone) composite sheath and a PCL core. When exposed to the wound's moist environment, PVP within the sheath gradually disintegrates, releasing the embedded n-CuO2 . Under a weakly acidic microenvironment (typically diabetic and infected wounds), n-CuO2 decomposes to release H2 O2 and Cu2+ ions and subsequently produce ·OH through chemodynamic reactions. This enables the anti-bacterial activity mediated by reactive oxygen species (ROS), suppressing the inflammation while enhancing angiogenesis. At the same time, the dissolution of PVP unveils unique nano-grooved surface patterns on the nanofibers, providing desirable cell-guiding function required for accelerated skin regeneration. Through meticulous material selection and design, this study pioneers the development of functional nanocomposites for multi-modal wound therapy, which holds great promise in guiding the path to healing for diabetic wounds.

Promoting neurite outgrowth and neural stem cell migration using aligned nanofibers decorated with protrusions and galectin-1 coating

Biomaterials integrated with both topological cues and biological modifications are urgently needed in regenerative medicine. Here, aligned nanofibrous scaffolds decorated with nanoscale SiO2 protrusions and galectin-1 coating are reported. Prospects in neurite outgrowth and neural stem cell migration are discussed for suitable use in neural tissue engineering.

Sustained release of basic fibroblast growth factor in micro/nanofibrous scaffolds promotes annulus fibrosus regeneration

Tissue engineering has promising applications in the treatment of intervertebral disc degeneration (IDD). The annulus fibrosus (AF) is critical for maintaining the physiological function of the intervertebral disc (IVD), but the lack of vessels and nutrition in AF makes it difficult to repair. In this study, we used hyaluronan (HA) micro-sol electrospinning and collagen type I (Col-I) self-assembly techniques to fabricate layered biomimetic micro/nanofibrous scaffolds, which released basic fibroblast growth factor (bFGF) to promote AF repair and regeneration after discectomy and endoscopic transforaminal discectomy. The bFGF enveloped in the core of the poly-L-lactic-acid (PLLA) core-shell structure was released in a sustained manner and promoted the adhesion and proliferation of AF cells (AFCs). Col-I could self-assemble on the shell of the PLLA core-shell scaffold to mimic the extracellular matrix (ECM) microenvironment, providing structural and biochemical cues for the regeneration of AF tissue. The in vivo studies showed that the micro/nanofibrous scaffolds promoted the repair of AF defects by simulating the microstructure of native AF tissue and inducing endogenous regeneration mechanism. Taken together, the biomimetic micro/nanofibrous scaffolds have clinical potential for the treatment of AF defects caused by IDD. STATEMENT OF SIGNIFICANCE: The annulus fibrosus (AF) is essential for the intervertebral disc (IVD) physiological function, yet it lacks vascularity and nutrition, making repair difficult. Micro-sol electrospinning technology and collagen type I (Col-I) self-assembly technique were combined in this study to create a layered biomimetic micro/nanofibrous scaffold that releases basic fibroblast growth factor (bFGF) to promote AF repair and regeneration. Col-I could mimic the extracellular matrix (ECM) microenvironment, in vivo, offering structural and biochemical cues for AF tissue regeneration. This research indicates that micro/nanofibrous scaffolds have clinical potential for treating AF deficits induced by IDD.

Radially Electrospun Fibrous Membrane Incorporated with Copper Peroxide Nanodots Capable of Self-Catalyzed Chemodynamic Therapy for Angiogenesis and Healing Acceleration of Diabetic Wounds

Vascular dysfunction severely hinders the healing process of diabetic wounds. Therefore, a radially structured fibrous membrane was fabricated through electrospinning by using a polycaprolactone (PCL) and polyvinylpyrrolidone (PVP) mixed solution containing copper peroxide nanoparticles (CPs) as the chemodynamic therapy (CDT) agents, aiming to simultaneously accelerate tissue regeneration and angiogenesis. The fabricated membrane allowed for the in situ H₂O₂ generation activated by the acidic diabetic microenvironment and the subsequent Fenton-type reactions to realize 99.4% elimination against Staphylococcus aureus. Besides, the released Cu²⁺ ions significantly enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in human umbilical vein endothelial cells (HUVECs), and they showed enhanced in vitro angiogenesis. Interestingly, the CP-embedded membrane also guided cell spreading and orientated migration of L929 fibroblasts along the fiber distribution through the radially aligned topology. The in vivo implantation indicated that the raidally structured membrane modified by CPs not only dramatically accelerated wound healing of diabetic Sprague-Dawley (SD) rats in 14 days but also promoted angiogenesis in wound sites. The combination of the in situ CDT with the radially structured morphology of the functional membrane is highly promising in applications to promote diabetic wound healing through anti-infection and revascularization.

Electrohydrodynamic Printing of Microfibrous Architectures with Cell-Scale Spacing for Improved Cellular Migration and Neurite Outgrowth

Electrohydrodynamic (EHD) printing provides unparalleled opportunities in fabricating microfibrous architectures to direct cellular orientation. However, it faces great challenges in depositing orderly microfibers with cell-scale spacing due to inherent fiber-fiber electrostatic interactions. Here a finite element method is established to analyze the electrostatic forces induced on the EHD-printed microfibers and the relationship between the fiber diameter and spacing for parallel deposition of EHD-printed microfibers is revealed theoretically and experimentally. It is found that uniform fiber arrangement can be achieved when the fiber spacing is five times larger than the fiber diameter. This finding enables the successful printing of parallel fibrous architectures with a fiber diameter of 4.9 ± 0.1 µm and a cell-scale fiber spacing of 25.6 ± 1.9 µm. The resultant microfibrous architectures exhibit unique capability to direct cellular alignment and enhance cellular density and migration as the fiber spacing decreases from 100 to 25 µm. The EHD-printed parallel microfibers with cell-scale spacing are found to improve the outgrowth length of neurites and accelerate the migration of Schwann cells from Dorsal Root Ganglion spheres, which facilitate the formation of densely-arranged and highly-aligned cellular constructs. The presented method is promising to produce biomimetic microfibrous architectures for functional nerve regeneration.

Submicron-Grooved Films Modulate the Directional Alignment and Biological Function of Schwann Cells

Topographical cues on material surfaces are crucial for guiding the behavior of nerve cells and facilitating the repair of peripheral nerve defects. Previously, micron-grooved surfaces have shown great potential in controlling nerve cell alignment for studying the behavior and functions of those cells and peripheral nerve regeneration. However, the effects of smaller-sized topographical cues, such as those in the submicron- and nano-scales, on Schwann cell behavior remain poorly understood. In this study, four different submicron-grooved polystyrene films (800/400, 800/100, 400/400, and 400/100) were fabricated to study the behavior, gene expression, and membrane potential of Schwann cells. The results showed that all submicron-grooved films could guide the cell alignment and cytoskeleton in a groove depth-dependent manner. Cell proliferation and cell cycle assays revealed that there was no significant difference between the submicron groove samples and the flat control. However, the submicron grooves can direct the migration of cells and upregulate the expression of critical genes in axon regeneration and myelination (e.g., MBP and Smad6). Finally, the membrane potential of the Schwann cells was significantly altered on the grooved sample. In conclusion, this study sheds light on the role of submicron-grooved patterns in regulating the behavior and function of Schwann cells, which provides unique insights for the development of implants for peripheral nerve regeneration.

Microfluidic Engineering of Crater-Terrain Hydrogel Microparticles: Toward Novel Cell Carriers

Fabrication and application of novel anisotropic microparticles are of wide interest. Herein, a new method for producing novel crater-terrain hydrogel microparticles is presented using a concept of droplet-aerosol impact and regional polymerization. The surface pattern of microparticles is similar to the widespread "crater" texture on the lunar surface and can be regulated by the impact morphology of aerosols on the droplet surface. Methodological applicability was demonstrated by producing ionic-cross-linked (alginate) and photo-cross-linked (poly(ethylene glycol) diacrylate, PEGDA) microparticles. Additionally, the crater-terrain microparticles (CTMs) can induce nonspecific protein absorption on their surface to acquire cell affinity, and they were exploited as cell carriers to load living cells. Cells could adhere and proliferate, and a special cellular adhesion fingerprint was observed on the novel cell carrier. Therefore, the scalable manufacturing method and biological potential make the engineered microparticles promising to open a new avenue for exploring cell-biomaterial crosstalk.

Non-electric bioelectrical analog strategy by a biophysical-driven nano-micro spatial anisotropic scaffold for regulating stem cell niche and tissue regeneration in a neuronal therapy

The slow regenerating rate and misdirected axonal growth are primary concerns that disturb the curative outcome of peripheral nerve repair. Biophysical intervention through nerve scaffolds can provide efficient, tunable and sustainable guidance for nerve regrowth. Herein, we fabricate the reduced graphene oxide (rGO)/polycaprolactone (PCL) scaffold characterized with anisotropic microfibers and oriented nanogrooves by electrospinning technique. Adipose-derived stem cells (ADSCs) are seeded on the scaffolds in vitro and the viability, neural differentiation efficiency and neurotrophic potential are investigated. RGO/PCL conduits reprogram the phenotype of seeded cells and efficiently repair 15 mm sciatic nerve defect in rats. In summary, biophysical cues on nerve scaffolds are key determinants to stem cell phenotype, and ADSC-seeded rGO/PCL oriented scaffolds are promising, controllable and sustainable approaches to enable peripheral nerve regeneration.

The impact of physical, biochemical, and electrical signaling on Schwann cell plasticity

Peripheral nervous system (PNS) injuries are an ongoing health care concern. While autografts and allografts are regarded as the current clinical standard for traumatic injury, there are inherent limitations that suggest alternative remedies should be considered for therapeutic purposes. In recent years, nerve guidance conduits (NGCs) have become increasingly popular as surgical repair devices, with a multitude of various natural and synthetic biomaterials offering potential to enhance the design of conduits or supplant existing technologies entirely. From a cellular perspective, it has become increasingly evident that Schwann cells (SCs), the primary glia of the PNS, are a predominant factor mediating nerve regeneration. Thus, the development of severe nerve trauma therapies requires a deep understanding of how SCs interact with their environment, and how SC microenvironmental cues may be engineered to enhance regeneration. Here we review the most recent advancements in biomaterials development and cell stimulation strategies, with a specific focus on how the microenvironment influences the behavior of SCs and can potentially lead to functional repair. We focus on microenvironmental cues that modulate SC morphology, proliferation, migration, and differentiation to alternative phenotypes. Promotion of regenerative phenotypic responses in SCs and other non-neuronal cells that can augment the regenerative capacity of multiple biomaterials is considered along with innovations and technologies for traumatic injury.

Neural tissue engineering: From bioactive scaffolds and in situ monitoring to regeneration

Peripheral nerve injury is a large-scale problem that annually affects more than several millions of people all over the world. It remains a great challenge to effectively repair nerve defects. Tissue engineered nerve guidance conduits (NGCs) provide a promising platform for peripheral nerve repair through the integration of bioactive scaffolds, biological effectors, and cellular components. Herein, we firstly describe the pathogenesis of peripheral nerve injuries at different orders of severity to clarify their microenvironments and discuss the clinical treatment methods and challenges. Then, we discuss the recent progress on the design and construction of NGCs in combination with biological effectors and cellular components for nerve repair. Afterward, we give perspectives on imaging the nerve and/or the conduit to allow for the in situ monitoring of the nerve regeneration process. We also cover the applications of different postoperative intervention treatments, such as electric field, magnetic field, light, and ultrasound, to the well-designed conduit and/or the nerve for improving the repair efficacy. Finally, we explore the prospects of multifunctional platforms to promote the repair of peripheral nerve injury.

Designing electrospun fiber platforms for efficient delivery of genetic material and genome editing tools

Electrospun fibers are versatile biomaterial platforms with great potential to support regeneration. Electrospun fiber characteristics such as fiber diameter, degree of alignment, rate of degradation, and surface chemistry enable the creation of unique, tunable scaffolds for various drug or gene delivery applications. The delivery of genetic material and genome editing tools via viral and non-viral vectors are approaches to control cellular protein production. However, immunogenicity, off-target effects, and low delivery efficiencies slow the progression of gene delivery strategies to clinical settings. The delivery of genetic material from electrospun fibers overcomes such limitations by allowing for localized, tunable delivery of genetic material. However, the process of electrospinning is harsh, and care must be taken to retain genetic material bioactivity. This review presents an up-to-date summary of strategies to incorporate genetic material onto or within electrospun fiber platforms to improve delivery efficiency and enhance the regenerative potential of electrospun fibers for various tissue engineering applications.

Electrospun Nanofibers for Manipulating the Soft Tissue Regeneration

Soft tissue damage is a common clinical problem that affects the lives of a large number of patients all over the world. It is of great importance to develop functional...

Time dependent adhesion of cells on nanorough surfaces

Understanding and controlling the mechanisms of cell adhesion to nanomaterials is essential in tissue engineering, regenerative medicine, the development of experimental models for the study of neurodegenerative diseases. Nonetheless, despite the great many of studies that have examined how cells interact with nanoscale surfaces, little is known about the temporal dimension of the process of adhesion. In a previous work, Decuzzi and Ferrari, by examining how the energy of a cell changes while binding to a nanoscale surface, determined a criterion to decide whether nanoroughness can either enhance or retard cell adhesion. While accurate, however their model template disregards the time variable. Here, starting from the work of Decuzzi and Ferrari, we have developed a mathematical model based on chemotaxis that describes how cells adhere to a nanorough surface over time. Relaxing the originating constraint of a fixed density of ligand molecules expressed by the cell membrane, we show that the strength of adhesion depends on time and that, for certain values of the model parameters, a cell can arrive to establish a stable adhesion to a substrate even if the process of binding is initially energetically unfavourable. We show that, for a cell-membrane stiffness of 10kPa, an initial density of receptors of 500bonds/μm², a specific and non-specific energy density of adhesion of 10^-5J/m² and 10^-7J/m², and roughness in the low nanometer range, cell adhesion forces can be completely activated from few seconds to some tens of minutes from the initial contact with the surface.

Biofunctionalization of electrospun fiber membranes by LbL-collagen/chondroitin sulfate nanocoating followed by mineralization for bone regeneration

It is of great significance to develop osteoinductive artificial scaffold for bone repair and regeneration. We constructed a biomimetic apatite interface on electrospun polycaprolactone fibers by combining layer-by-layer (LbL) nanocoating with mineralization to fabricate an osteoinductive artificial scaffold. After polydopamine modification, cationic type-І collagen and anionic chondroitin sulfate were sequentially adsorbed on the fiber surface. The fibers coated with the multilayer components served as the precursor matrix to induce apatite deposition. By adjusting the number of the layers and duration of mineralization, the nanoscale morphology of composite fibers was optimized. When ten bilayers of the collagen and chondroitin sulfate were deposited onto the fibers followed by one day-mineralization, the obtained polycaprolactone-apatite composite scaffolds significantly promoted the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. In a subcutaneous implantation in mice, this composite fiber membrane enhanced in vivo ectopic osteogenesis. Our nano-architectural scaffolds were able to mimic the composition and structure of the bone matrix to a certain extent, holding great potential for bone repair and regeneration.

Micro-and-nanometer topological gradient of block copolymer fibrous scaffolds towards region-specific cell regulation

Regulating cell behavior and function by surface topography has drawn significant attention in tissue engineering. Herein, a gradient fibrous scaffold comprising anisotropic aligned fibers and isotropic annealed fibers was developed to provide a controllable direction of cell migration, adhesion, and spreading. The electrospun aligned fibers were engraved to create surface gradients with micro-and-nanometer roughness through block copolymer (BCP) self-assembly induced by selective solvent vapor annealing (SVA). The distinct manipulation of cell behavior by annealed fibrous scaffolds with tailored self-assembled nanostructure and welded fibrous microstructure has been illustrated by in situ/ex situ small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and in vitro cell culture. Further insights into the effect of integrated gradient fibrous scaffold were gained at the level of protein expression. From the perspective of gradient topology, this region-specific scaffold based on BCP fibers shows the prospect of guiding cell migration, adhesion and spreading and provides a generic method for designing biomaterials for tissue-engineering.

Multidrug-loaded electrospun micro/nanofibrous membranes: Fabrication strategies, release behaviors and applications in regenerative medicine

Electrospun micro/nanofibrous membranes (EFMs) have been widely investigated as local drug delivery systems. Multiple drugs can be simultaneously incorporated into one EFM to create synergistic effects, reduce side effects, and play their respective roles in the complex physiological processes of tissue regeneration and postoperative adhesion prevention. Due to the versatile electrospinning techniques, sustained and programmed release behaviors of multiple drugs could be achieved by modulating the structure of the EFMs and the location of the drugs. In this review, various multidrug incorporation approaches based on electrospinning are overviewed. In particular, the advantages and limitations of each drug incorporation technique, the methods to control drug release and the effect of one drug release on another are discussed. Then the applications of multidrug-loaded EFMs in regenerative medicine, including wound healing, bone regeneration, vascular tissue engineering, nerve regeneration, periodontal regeneration and adhesion prevention are comprehensively reviewed. Finally, the future perspectives and challenges in the research of multidrug-loaded EFMs are discussed.

Chain-end functionalization of living helical polyisocyanides through a Pd(ii)-mediated Sonogashira coupling reaction

Various functional helical polymers were constructed through chain-end functionalization of living helical polyisocyanides through a Pd(ii)-mediated Sonogashira coupling reaction.

Electrospun Fiber Scaffolds for Engineering Glial Cell Behavior to Promote Neural Regeneration

Electrospinning is a fabrication technique used to produce nano- or micro- diameter fibers to generate biocompatible, biodegradable scaffolds for tissue engineering applications. Electrospun fiber scaffolds are advantageous for neural regeneration because they mimic the structure of the nervous system extracellular matrix and provide contact guidance for regenerating axons. Glia are non-neuronal regulatory cells that maintain homeostasis in the healthy nervous system and regulate regeneration in the injured nervous system. Electrospun fiber scaffolds offer a wide range of characteristics, such as fiber alignment, diameter, surface nanotopography, and surface chemistry that can be engineered to achieve a desired glial cell response to injury. Further, electrospun fibers can be loaded with drugs, nucleic acids, or proteins to provide the local, sustained release of such therapeutics to alter glial cell phenotype to better support regeneration. This review provides the first comprehensive overview of how electrospun fiber alignment, diameter, surface nanotopography, surface functionalization, and therapeutic delivery affect Schwann cells in the peripheral nervous system and astrocytes, oligodendrocytes, and microglia in the central nervous system both in vitro and in vivo. The information presented can be used to design and optimize electrospun fiber scaffolds to target glial cell response to mitigate nervous system injury and improve regeneration.

Bio-inspired chiral self-assemblies promoted neuronal differentiation of retinal progenitor cells through activation of metabolic pathway

Retinal degeneration is a main class of ocular diseases. So far, retinal progenitor cell (RPC) transplantation has been the most potential therapy for it, in which promoting RPCs neuronal differentiation remains an unmet challenge. To address this issue, innovatively designed _{L/ d -} phenylalanine based chiral nanofibers (LPG and DPG) are employed and it finds that chirality of fibers can efficiently regulate RPCs differentiation. qPCR, western blot, and immunofluorescence analysis show that right-handed helical DPG nanofibers significantly promote RPCs neuronal differentiation, whereas left-handed LPG nanofibers decrease this effect. These effects are mainly ascribed to the stereoselective interaction between chiral helical nanofibers and retinol-binding protein 4 (RBP4, a key protein in the retinoic acid (RA) metabolic pathway). The findings of chirality-dependent neuronal differentiation provide new strategies for treatment of neurodegenerative diseases via optimizing differentiation of transplanted stem cells on chiral nanofibers.

Fabrication and Characterization of Neurocompatible Ulvan-Based Layer-by-Layer Films

Construction of extracellular matrix-mimetic nanofilms has considerable potential in biomedical and nanomedicinal fields. In this work, we fabricated neurocompatible layer-by-layer (LbL) films based on ulvan (ULV), a highly sulfated polysaccharide having compositional similarity to glycosaminoglycans that play important functional roles in the brain. ULV was durably assembled as a film with chitosan, another marine-derived polysaccharide, and the film enabled the stable adhesion of primary hippocampal neurons with high viability, comparable to the conventional poly-d-lysine surface. Notably, the ULV-based LbL films accelerated neurite outgrowth and selectively suppressed the adhesion of astrocytes, highlighting its potential as an advanced platform for neural implants and devices.