Collagen/heparan sulfate porous scaffolds loaded with neural stem cells improve neurological function in a rat model of traumatic brain injury

Promotion of nerve regeneration and motor function recovery in SCI rats using LOCAS-iPSCs-NSCs

BACKGROUND

Spinal cord injury (SCI) is a severe traumatic spinal condition with a poor prognosis. In this study, a scaffold called linearly ordered collagen aggregates (LOCAS) was created and loaded with induced pluripotent stem cells (iPSCs)-derived neural stem cells (NSCs) from human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) to treat SCI in a rat model.

METHODS

The rats underwent a complete transection SCI resulting in a 3-mm break at either the T9 or T10 level of the spinal cord.

RESULTS

Scanning electron microscope analysis revealed a uniform pore structure on the coronal plane of the scaffold. The LOCAS had a porosity of 88.52% and a water absorption of 1161.67%. Its compressive modulus and stress were measured at 4.1 MPa and 205 kPa, respectively, with a degradation time of 10 weeks. After 12 weeks, rats in the LOCAS-iPSCs-NSCs group exhibited significantly higher BBB scores (8.6) compared to the LOCAS-iPSCs-NSCs group (5.6) and the Model group (4.2). The CatWalk analysis showed improved motion trajectory, regularity index (RI), and swing speed in the LOCAS-iPSCs-NSCs group compared to the other groups. Motor evoked potentials latency was lower and amplitude was higher in the LOCAS-iPSCs-NSCs group, indicating better neural function recovery. Histological analysis demonstrated enhanced neuronal differentiation of NSCs and nerve fiber regeneration promoted by LOCAS-iPSCs-NSCs, leading to improved motor function recovery in rats. The LOCAS scaffold facilitated ordered neurofilament extension and guided nerve regeneration.

CONCLUSIONS

The combination of LOCAS and iPSCs-NSCs demonstrated a positive therapeutic impact on motor function recovery and tissue repair in rats with SCI. This development offers a more resilient bionic microenvironment and presents novel possibilities for clinical SCI repair.

Mechanisms of vascular injury in neurotrauma: A critical review of the literature

One in every two individuals will experience a traumatic brain injury in their lifetime with significant impacts on the global economy and healthcare system each year. Neurovascular injury is a key aspect of neurotrauma to both the brain and the spinal cord and an important avenue of current and future research seeking innovative therapies. In this paper, we discuss primary and secondary neurotrauma, mechanisms of injury, the glymphatic system, repair and recovery. Each of these topics are directly connected to the vasculature of the central nervous system, affecting severity of injury and recovery. Consequently, neurovascular injury in trauma represents a promising target for future therapeutics and innovation.

Mapping knowledge of the stem cell in traumatic brain injury: a bibliometric and visualized analysis

Background

Traumatic brain injury (TBI) is a brain function injury caused by external mechanical injury. Primary and secondary injuries cause neurological deficits that mature brain tissue cannot repair itself. Stem cells can self-renewal and differentiate, the research of stem cells in the pathogenesis and treatment of TBI has made significant progress in recent years. However, numerous articles must be summarized to analyze hot spots and predict trends. This study aims to provide a panorama of knowledge and research hotspots through bibliometrics.

Method

We searched in the Web of Science Core Collection (WoSCC) database to identify articles pertaining to TBI and stem cells published between 2000 and 2022. Visualization knowledge maps, including co-authorship, co-citation, and co-occurrence analysis were generated by VOSviewer, CiteSpace, and the R package "bibliometrix."

Results

We retrieved a total of 459 articles from 45 countries. The United States and China contributed the majority of publications. The number of publications related to TBI and stem cells is increasing yearly. Tianjin Medical University was the most prolific institution, and Professor Charles S. Cox, Jr. from the University of Texas Health Science Center at Houston was the most influential author. The Journal of Neurotrauma has published the most research articles on TBI and stem cells. Based on the burst references, "immunomodulation," "TBI," and "cellular therapy" have been regarded as research hotspots in the field. The keywords co-occurrence analysis revealed that "exosomes," "neuroinflammation," and "microglia" were essential research directions in the future.

Conclusion

Research on TBI and stem cells has shown a rapid growth trend in recent years. Existing studies mainly focus on the activation mechanism of endogenous neural stem cells and how to make exogenous stem cell therapy more effective. The combination with bioengineering technology is the trend in this field. Topics related to exosomes and immune regulation may be the future focus of TBI and stem cell research.

Chronic motor performance following different traumatic brain injury severity-A systematic review

Introduction

Traumatic brain injury (TBI) is now known to be a chronic disease, causing ongoing neurodegeneration and linked to increased risk of neurodegenerative motor diseases, such as Parkinson's disease and amyotrophic lateral sclerosis. While the presentation of motor deficits acutely following traumatic brain injury is well-documented, however, less is known about how these evolve in the long-term post-injury, or how the initial severity of injury affects these outcomes. The purpose of this review, therefore, was to examine objective assessment of chronic motor impairment across the spectrum of TBI in both preclinical and clinical models.

Methods

PubMed, Embase, Scopus, and PsycINFO databases were searched with a search strategy containing key search terms for TBI and motor function. Original research articles reporting chronic motor outcomes with a clearly defined TBI severity (mild, repeated mild, moderate, moderate-severe, and severe) in an adult population were included.

Results

A total of 97 studies met the inclusion criteria, incorporating 62 preclinical and 35 clinical studies. Motor domains examined included neuroscore, gait, fine-motor, balance, and locomotion for preclinical studies and neuroscore, fine-motor, posture, and gait for clinical studies. There was little consensus among the articles presented, with extensive differences both in assessment methodology of the tests and parameters reported. In general, an effect of severity was seen, with more severe injury leading to persistent motor deficits, although subtle fine motor deficits were also seen clinically following repeated injury. Only six clinical studies investigated motor outcomes beyond 10 years post-injury and two preclinical studies to 18-24 months post-injury, and, as such, the interaction between a previous TBI and aging on motor performance is yet to be comprehensively examined.

Conclusion

Further research is required to establish standardized motor assessment procedures to fully characterize chronic motor impairment across the spectrum of TBI with comprehensive outcomes and consistent protocols. Longitudinal studies investigating the same cohort over time are also a key for understanding the interaction between TBI and aging. This is particularly critical, given the risk of neurodegenerative motor disease development following TBI.

Mimicking the neural stem cell niche: An engineer’s view of cell: material interactions

Neural stem cells have attracted attention in recent years to treat neurodegeneration. There are two neurogenic regions in the brain where neural stem cells reside, one of which is called the subventricular zone (SVZ). The SVZ niche is a complicated microenvironment providing cues to regulate self-renewal and differentiation while maintaining the neural stem cell’s pool. Many scientists have spent years understanding the cellular and structural characteristics of the SVZ niche, both in homeostasis and pathological conditions. On the other hand, engineers focus primarily on designing platforms using the knowledge they acquire to understand the effect of individual factors on neural stem cell fate decisions. This review provides a general overview of what we know about the components of the SVZ niche, including the residing cells, extracellular matrix (ECM), growth factors, their interactions, and SVZ niche changes during aging and neurodegenerative diseases. Furthermore, an overview will be given on the biomaterials used to mimic neurogenic niche microenvironments and the design considerations applied to add bioactivity while meeting the structural requirements. Finally, it will discuss the potential gaps in mimicking the microenvironment.

3D printing of injury-preconditioned secretome/collagen/heparan sulfate scaffolds for neurological recovery after traumatic brain injury in rats

BACKGROUND

The effects of traumatic brain injury (TBI) can include physical disability and even death. The development of effective therapies to promote neurological recovery is still a challenging problem. 3D-printed biomaterials are considered to have a promising future in TBI repair. The injury-preconditioned secretome derived from human umbilical cord blood mesenchymal stem cells showed better stability in neurological recovery after TBI. Therefore, it is reasonable to assume that a biological scaffold loaded with an injury-preconditioned secretome could facilitate neural network reconstruction after TBI.

METHODS

In this study, we fabricated injury-preconditioned secretome/collagen/heparan sulfate scaffolds by 3D printing. The scaffold structure and porosity were examined by scanning electron microscopy and HE staining. The cytocompatibility of the scaffolds was characterized by MTT analysis, HE staining and electron microscopy. The modified Neurological Severity Score (mNSS), Morris water maze (MWM), and motor evoked potential (MEP) were used to examine the recovery of cognitive and locomotor function after TBI in rats. HE staining, silver staining, Nissl staining, immunofluorescence, and transmission electron microscopy were used to detect the reconstruction of neural structures and pathophysiological processes. The biocompatibility of the scaffolds in vivo was characterized by tolerance exposure and liver/kidney function assays.

RESULTS

The excellent mechanical and porosity characteristics of the composite scaffold allowed it to efficiently regulate the secretome release rate. MTT and cell adhesion assays demonstrated that the scaffold loaded with the injury-preconditioned secretome (3D-CH-IB-ST) had better cytocompatibility than that loaded with the normal secretome (3D-CH-ST). In the rat TBI model, cognitive and locomotor function including mNSS, MWM, and MEP clearly improved when the scaffold was transplanted into the damage site. There is a significant improvement in nerve tissue at the site of lesion. More abundant endogenous neurons with nerve fibers, synaptic structures, and myelin sheaths were observed in the 3D-CH-IB-ST group. Furthermore, the apoptotic response and neuroinflammation were significantly reduced and functional vessels were observed at the injury site. Good exposure tolerance in vivo demonstrated favorable biocompatibility of the scaffold.

CONCLUSIONS

Our results demonstrated that injury-preconditioned secretome/collagen/heparan sulfate scaffolds fabricated by 3D printing promoted neurological recovery after TBI by reconstructing neural networks, suggesting that the implantation of the scaffolds could be a novel way to alleviate brain damage following TBI.

Hypoxia-pretreated mesenchymal stem cell-derived exosomes-loaded low-temperature extrusion 3D-printed implants for neural regeneration after traumatic brain injury in canines

Regenerating brain defects after traumatic brain injury (TBI) still remains a significant difficulty, which has motivated interest in 3D printing to design superior replacements for brain implantation. Collagen has been applied to deliver cells or certain neurotrophic factors for neuroregeneration. However, its fast degradation rate and poor mechanical strength prevent it from being an excellent implant material after TBI. In the present study, we prepared 3D-printed collagen/silk fibroin/hypoxia-pretreated human umbilical cord mesenchymal stem cells (HUCMSCs)-derived exosomes scaffolds (3D-CS-HMExos), which possessed favorable physical properties suitable biocompatibility and biodegradability and were attractive candidates for TBI treatment. Furthermore, inspired by exosomal alterations resulting from cells in different external microenvironments, exosomes were engineered through hypoxia stimulation of mesenchymal stem cells and were proposed as an alternative therapy for promoting neuroregeneration after TBI. We designed hypoxia-preconditioned (Hypo) exosomes derived from HUCMSCs (Hypo-MExos) and proposed them as a selective therapy to promote neuroregeneration after TBI. For the current study, 3D-CS-HMExos were prepared for implantation into the injured brains of beagle dogs. The addition of hypoxia-induced exosomes further exhibited better biocompatibility and neuroregeneration ability. Our results revealed that 3D-CS-HMExos could significantly promote neuroregeneration and angiogenesis due to the doping of hypoxia-induced exosomes. In addition, the 3D-CS-HMExos further inhibited nerve cell apoptosis and proinflammatory factor (TNF-α and IL-6) expression and promoted the expression of an anti-inflammatory factor (IL-10), ultimately enhancing the motor functional recovery of TBI. We proposed that the 3D-CS-loaded encapsulated hypoxia-induced exosomes allowed an adaptable environment for neuroregeneration, inhibition of inflammatory factors and promotion of motor function recovery in TBI beagle dogs. These beneficial effects implied that 3D-CS-HMExos implants could serve as a favorable strategy for defect cavity repair after TBI.

3D-printed collagen/silk fibroin/secretome derived from bFGF-pretreated HUCMSCs scaffolds enhanced therapeutic ability in canines traumatic brain injury model

The regeneration of brain tissue poses a great challenge because of the limited self-regenerative capabilities of neurons after traumatic brain injury (TBI). For this purpose, 3D-printed collagen/silk fibroin/secretome derived from human umbilical cord blood mesenchymal stem cells (HUCMSCs) pretreated with bFGF scaffolds (3D-CS-bFGF-ST) at a low temperature were prepared in this study. From an in vitro perspective, 3D-CS-bFGF-ST showed good biodegradation, appropriate mechanical properties, and good biocompatibility. In regard to vivo, during the tissue remodelling processes of TBI, the regeneration of brain tissues was obviously faster in the 3D-CS-bFGF-ST group than in the other two groups (3D-printed collagen/silk fibroin/secretome derived from human umbilical cord blood mesenchymal stem cells (3D-CS-ST) group and TBI group) by motor assay, histological analysis, and immunofluorescence assay. Satisfactory regeneration was achieved in the two 3D-printed scaffold-based groups at 6 months postsurgery, while the 3D-CS-bFGF-ST group showed a better outcome than the 3D-CS-ST group.

Periostin promotes nucleus pulposus cells apoptosis by activating the Wnt/β-catenin signaling pathway

Intervertebral disc (IVD) degeneration (IVDD) is closely linked to degenerative spinal disease, resulting in disability, poor quality of life, and financial burden. Apoptosis of nucleus pulposus (NP) cells (NPCs) is a key pathological basis of IVDD. Periostin (POSTN), an extracellular matrix protein, is expressed in many tissues, whereas its abnormal expression is associated with IVDD. The conventional Wnt/β-catenin pathway is also involved in IVDD and contributes to NPCs apoptosis. However, research on the mechanisms of POSTN in IVDD is lacking. This study investigated the relationship between POSTN and β-catenin expression in degenerated IVDs. We detected the expression of POSTN, β-catenin, and cleaved-caspase-3 (C-caspase3) in degenerated and non-degenerated IVD tissues of different grades (n = 8) using RT-qPCR, immunohistochemical staining, and western blotting analysis. Next, we explored the effects of recombinant periostin (rPOSTN) and isoquercitrin (Iso), an inhibitor of the Wnt/β-catenin pathway, on NPCs apoptosis. Finally, we inhibited the expression of POSTN in degenerated NPCs in vivo and investigated the anti-apoptotic effect. The expression of β-catenin, POSTN, and C-caspase3 in severe degenerative IVDs was significantly higher than that in mild degenerative IVDs. These findings were confirmed in rat and cell-based degenerative models. When treated with rPOSTN, the Wnt/β-catenin pathway activity and cell apoptosis were time- and dose-dependent. However, rPOSTN-induced NPCs apoptosis decreased after iso-induced inhibition of the Wnt/β-catenin pathway. POSTN inhibition reduced apoptosis but was restored by rPOSTN re-addition. Lastly, POSTN inhibition ameliorated puncture-induced IVDD in vivo. Overall, our study demonstrated that POSTN promotes NPCs apoptosis and aggravates degeneration by activating the Wnt/β-catenin pathway.

Carbohydrate based biomaterials for neural interface applications

Neuroprosthetic devices that record and modulate neural activities have demonstrated immense potential for bypassing or restoring lost neurological functions due to neural injuries and disorders. However, implantable electrical devices interfacing with brain tissue are susceptible to a series of inflammatory tissue responses along with mechanical or electrical failures which can affect the device performance over time. Several biomaterial strategies have been implemented to improve device-tissue integration for high quality and stable performance. Ranging from developing smaller, softer, and more flexible electrode designs to introducing bioactive coatings and drug-eluting layers on the electrode surface, such strategies have shown different degrees of success but with limitations. With their hydrophilic properties and specific bioactivities, carbohydrates offer a potential solution for addressing some of the limitations of the existing biomolecular approaches. In this review, we summarize the role of polysaccharides in the central nervous system, with a primary focus on glycoproteins and proteoglycans, to shed light on their untapped potential as biomaterials for neural implants. Utilization of glycosaminoglycans for neural interface and tissue regeneration applications is comprehensively reviewed to provide the current state of carbohydrate-based biomaterials for neural implants. Finally, we will discuss the challenges and opportunities of applying carbohydrate-based biomaterials for neural tissue interfaces.

3D-printed collagen/chitosan/secretome derived from HUCMSCs scaffolds for efficient neural network reconstruction in canines with traumatic brain injury

The secretome secreted by stem cells and bioactive material has emerged as a promising therapeutic choice for traumatic brain injury (TBI). We aimed to determine the effect of 3D-printed collagen/chitosan/secretome derived from human umbilical cord blood mesenchymal stem cells scaffolds (3D-CC-ST) on the injured tissue regeneration process. 3D-CC-ST was performed using 3D printing technology at a low temperature (−20°C), and the physical properties and degeneration rate were measured. The utilization of low temperature contributed to a higher cytocompatibility of fabricating porous 3D architectures that provide a homogeneous distribution of cells. Immediately after the establishment of the canine TBI model, 3D-CC-ST and 3D-CC (3D-printed collagen/chitosan scaffolds) were implanted into the cavity of TBI. Following implantation of scaffolds, neurological examination and motor evoked potential detection were performed to analyze locomotor function recovery. Histological and immunofluorescence staining were performed to evaluate neuro-regeneration. The group treated with 3D-CC-ST had good performance of behavior functions. Implanting 3D-CC-ST significantly reduced the cavity area, facilitated the regeneration of nerve fibers and vessel reconstruction, and promoted endogenous neuronal differentiation and synapse formation after TBI. The implantation of 3D-CC-ST also markedly reduced cell apoptosis and regulated the level of systemic inflammatory factors after TBI.

Application and prospects of high-throughput screening for in vitro neurogenesis

Over the past few decades, high-throughput screening (HTS) has made great contributions to new drug discovery. HTS technology is equipped with higher throughput, minimized platforms, more automated and computerized operating systems, more efficient and sensitive detection devices, and rapid data processing systems. At the same time, in vitro neurogenesis is gradually becoming important in establishing models to investigate the mechanisms of neural disease or developmental processes. However, challenges remain in generating more mature and functional neurons with specific subtypes and in establishing robust and standardized three-dimensional (3D) in vitro models with neural cells cultured in 3D matrices or organoids representing specific brain regions. Here, we review the applications of HTS technologies on in vitro neurogenesis, especially aiming at identifying the essential genes, chemical small molecules and adaptive microenvironments that hold great prospects for generating functional neurons or more reproductive and homogeneous 3D organoids. We also discuss the developmental tendency of HTS technology, e.g., so-called next-generation screening, which utilizes 3D organoid-based screening combined with microfluidic devices to narrow the gap between in vitro models and in vivo situations both physiologically and pathologically.

Kappa-carrageenan/chitosan/gelatin scaffolds enriched with potassium chloride for bone tissue engineering

Kappa-carrageenan is a biocompatible natural polysaccharide able to form hydrogels for tissue regeneration. In bone tissue engineering, achieving a bioactive microenvironment with appropriate mechanical properties in polysaccharide-based scaffolds remains a challenge. This study aims to fabricate 3D scaffolds comprising kappa-carrageenan, chitosan and gelatin, crosslinked with KCl, and evaluate their mechanical and biological properties for bone tissue engineering. The produced scaffolds include kappa-carrageenan/chitosan (KC), kappa-carrageenan/chitosan/gelatin (KCG), kappa-carrageenan/chitosan/gelatin enriched with KCl (KCG-KCl), and chitosan/gelatin (CG). All scaffolds present degradation rates ranging from 30% weight loss on day 21, pore size distribution in the range of 100-160 μm and porosity above 80%. The Young modulus values range from 9 to 256 kPa, with the KCl-containing KCG scaffolds demonstrating the highest values, validating the role of KCl in the coil to helix transition of kappa-carrageenan leading to firmer structures. In vitro biological evaluation indicates that pre-osteoblasts proliferate significantly from day 3 up to day 14 on all scaffold compositions. The alkaline phosphatase activity shows a significant increase up to day 14. The calcium production displays a constant increase from day 14 up to day 28, proving that all scaffold compositions support the osteogenic differentiation potential.

Fractone Stem Cell Niche Components Provide Intuitive Clues in the Design of New Therapeutic Procedures/Biomatrices for Neural Repair

The aim of this study was to illustrate recent developments in neural repair utilizing hyaluronan as a carrier of olfactory bulb stem cells and in new bioscaffolds to promote neural repair. Hyaluronan interacts with brain hyalectan proteoglycans in protective structures around neurons in perineuronal nets, which also have roles in the synaptic plasticity and development of neuronal cognitive properties. Specialist stem cell niches termed fractones located in the sub-ventricular and sub-granular regions of the dentate gyrus of the hippocampus migrate to the olfactory bulb, which acts as a reserve of neuroprogenitor cells in the adult brain. The extracellular matrix associated with the fractone stem cell niche contains hyaluronan, perlecan and laminin α5, which regulate the quiescent recycling of stem cells and also provide a means of escaping to undergo the proliferation and differentiation to a pluripotent migratory progenitor cell type that can participate in repair processes in neural tissues. Significant improvement in the repair of spinal cord injury and brain trauma has been reported using this approach. FGF-2 sequestered by perlecan in the neuroprogenitor niche environment aids in these processes. Therapeutic procedures have been developed using olfactory ensheathing stem cells and hyaluronan as a carrier to promote neural repair processes. Now that recombinant perlecan domain I and domain V are available, strategies may also be expected in the near future using these to further promote neural repair strategies.

A Preliminary Study on the Relationship between Serum Heparan Sulfate and Cancer-Related Cognitive Impairment: The Moderating Role of Oxidative Stress in Patients with Colorectal Cancer

Cancer-related cognitive impairment (CRCI) has been frequently reported in colorectal cancer survivors. Heparan sulfate (HS) was gradually considered to be related to cognitive disorders. The effect and potential mechanism of HS on CRCI in colorectal cancer patients were unexplored. In this study, all participants were divided into a cognitive impaired group and a cognitive normal group. The concentrations of oxidative stress factors and HS in serum were detected. Associations among HS, oxidative stress factors and CRCI were evaluated. Participants with cognitive impairment exhibited increased levels of HS, GSH, SOD and MDA, compared to the patients with normal cognitive performance. The independent significant association was found between HS and CRCI after controlling for various covariates. The higher concentrations of HS were related to the decreased cognitive performance among survivors who reported higher levels of GSH (β = 0.080, p = 0.002). Moreover, the nonlinear association between the level of HS and cognitive scores was confirmed using the restricted cubic splines (p < 0.001). These results indicated that the increased concentrations of circulating HS had a nonlinear negative connection with cognitive performance in colorectal cancer survivors, which was moderated by GSH. HS might be a new biomolecule for the identification and management of patients with CRCI.

Biomaterial-based strategies for in vitro neural models

In vitro models have been used as a complementary tool to animal studies in understanding the nervous system's physiological mechanisms and pathological disorders, while also serving as platforms to evaluate the safety and efficiency of therapeutic candidates. Following recent advances in materials science, micro- and nanofabrication techniques and cell culture systems, in vitro technologies have been rapidly gaining the potential to bridge the gap between animal and clinical studies by providing more sophisticated models that recapitulate key aspects of the structure, biochemistry, biomechanics, and functions of human tissues. This was made possible, in large part, by the development of biomaterials that provide cells with physicochemical features that closely mimic the cellular microenvironment of native tissues. Due to the well-known material-driven cellular response and the importance of mimicking the environment of the target tissue, the selection of optimal biomaterials represents an important early step in the design of biomimetic systems to investigate brain structures and functions. This review provides a comprehensive compendium of commonly used biomaterials as well as the different fabrication techniques employed for the design of neural tissue models. Furthermore, the authors discuss the main parameters that need to be considered to develop functional platforms not only for the study of brain physiological functions and pathological processes but also for drug discovery/development and the optimization of biomaterials for neural tissue engineering.

Periostin: An Emerging Molecule With a Potential Role in Spinal Degenerative Diseases

Periostin, an extracellular matrix protein, is widely expressed in a variety of tissues and cells. It has many biological functions and is related to many diseases: for example, it promotes cell proliferation and differentiation in osteoblasts, which are closely related to osteoporosis, and mediates cell senescence and apoptosis in chondrocytes, which are involved in osteoarthritis. Furthermore, it also plays an important role in mediating inflammation and reconstruction during bronchial asthma, as well as in promoting bone development, reconstruction, repair, and strength. Therefore, periostin has been explored as a potential biomarker for various diseases. Recently, periostin has also been found to be expressed in intervertebral disc cells as a component of the intervertebral extracellular matrix, and to play a crucial role in the maintenance and degeneration of intervertebral discs. This article reviews the biological role of periostin in bone marrow-derived mesenchymal stem cells, osteoblasts, osteoclasts, chondrocytes, and annulus fibrosus and nucleus pulposus cells, which are closely related to spinal degenerative diseases. The study of its pathophysiological effects is of great significance for the diagnosis and treatment of spinal degeneration, although additional studies are needed.

Effect of poly (lactic acid) porous membrane prepared via phase inversion induced by water droplets on 3T3 cell behavior

Phase inversion induced by water droplets has garnered attention in the field of polymer science as a novel method for preparing porous membranes. This study investigates the effect of the porous structure of poly (lactic acid) (PLA) membranes prepared through phase inversion induced by water droplets at four different temperatures (25, 50, 75, and 100 °C) on the morphology and proliferation of 3T3 cells. The surface properties of the PLA porous membrane, including pore size, pore size distribution, surface roughness, surface hydrophilicity, and cytocompatibility with 3T3 cells, were evaluated. The results indicated that the synthesized PLA membrane had two surfaces with different structures. The upper surface in contact with the water droplets during preparation contained uniformly distributed micropores, whereas the bottom surface was smooth and composed of small particles in contacted with the mold. The upper surface showed high cytocompatibility with 3T3 cells, and the 3T3 cells migrated and grew within the pores at 25 °C. In contrast, the bottom surface exhibited low biocompatibility with the 3T3 cells. Our study has wide-ranging implications and will improve the fabrication and implementation of 3D cultured scaffolds with excellent cytocompatibility.

Neurorepair and Regeneration of the Brain: A Decade of Bioscaffolds and Engineered Microtissue

Repairing the human brain remains a challenge, despite the advances in the knowledge of inflammatory response to injuries and the discovery of adult neurogenesis. After brain injury, the hostile microenvironment and the lack of structural support for neural cell repopulation, anchoring, and synapse formation reduce successful repair chances. In the past decade, we witnessed the rise of studies regarding bioscaffolds’ use as support for neuro repair. A variety of natural and synthetic materials is available and have been used to replace damaged tissue. Bioscaffolds can assume different shapes and may or may not carry a diversity of content, such as stem cells, growth factors, exosomes, and si/miRNA that promote specific therapeutic effects and stimulate brain repair. The use of these external bioscaffolds and the creation of cell platforms provide the basis for tissue engineering. More recently, researchers were able to engineer brain organoids, neural networks, and even 3D printed neural tissue. The challenge in neural tissue engineering remains in the fabrication of scaffolds with precisely controlled topography and biochemical cues capable of directing and controlling neuronal cell fate. The purpose of this review is to highlight the existing research in the growing field of bioscaffolds’ development and neural tissue engineering. Moreover, this review also draws attention to emerging possibilities and prospects in this field.