首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Fully simulating the components and microstructures of soft tissue is a challenge for its functional regeneration. A new aligned hydrogel microfiber scaffold for spinal cord regeneration is constructed with photocrosslinked gelatin methacryloyl (GelMA) and electrospinning technology. The directional porous hydrogel fibrous scaffold consistent with nerve axons is vital to guide cell migration and axon extension. The GelMA hydrogel electrospun fibers soak up water more than six times their weight, with a lower Young's modulus, providing a favorable survival and metabolic environment for neuronal cells. GelMA fibers further demonstrate higher antinestin, anti‐Tuj‐1, antisynaptophysin, and anti‐CD31 gene expression in neural stem cells, neuronal cells, synapses, and vascular endothelial cells, respectively. In contrast, anti‐GFAP and anti‐CS56 labeled astrocytes and glial scars of GelMA fibers are shown to be present in a lesser extent compared with gelatin fibers. The soft bionic scaffold constructed with electrospun GelMA hydrogel fibers not only facilitates the migration of neural stem cells and induces their differentiation into neuronal cells, but also inhibits the glial scar formation and promotes angiogenesis. Moreover, the scaffold with a high degree of elasticity can resist deformation without the protection of a bony spinal canal. The bioinspired aligned hydrogel microfiber proves to be efficient and versatile in triggering functional regeneration of the spinal cord.  相似文献   

2.
Conductive hydrogel scaffolds have important applications for electroactive tissue repairs. However, the development of conductive hydrogel scaffolds tends to incorporate nonbiodegradable conductive nanomaterials that will remain in the human body as foreign matters. Herein, a biodegradable conductive hybrid hydrogel is demonstrated based on the integration of black phosphorus (BP) nanosheets into the hydrogel matrix. To address the challenge of applying BP nanosheets in tissue engineering due to its intrinsic instability, a polydopamine (PDA) modification method is developed to improve the stability. Moreover, PDA modification also enhances interfacial bonding between pristine BP nanosheets and the hydrogel matrix. The incorporation of polydopamine‐modified black phosphorous (BP@PDA) nanosheets into the gelatin methacryloyl (GelMA) hydrogels significantly enhances the electrical conductivity of the hydrogels and improves the cell migration of mesenchymal stem cells (MSCs) within the 3D scaffolds. On the basis of the gene expression and protein level assessments, the BP@PDA‐incorporated GelMA scaffold can significantly promote the differentiation of MSCs into neural‐like cells under the synergistic electrical stimulation. This strategy of integrating biodegradable conductive BP nanomaterials within a biocompatible hydrogel provides a new insight into the design of biomaterials for broad applications in tissue engineering of electroactive tissues, such as neural, cardiac, and skeletal muscle tissues.  相似文献   

3.
Engineering living tissues that simulate their natural counterparts is a dynamic area of research. Among the various models of biological tissues being developed, fiber‐shaped cellular architectures, which can be used as artificial blood vessels or muscle fibers, have drawn particular attention. However, the fabrication of continuous microfiber substrates for culturing cells is still limited to a restricted number of polymers (e.g., alginate) having easy processability but poor cell–material interaction properties. Moreover, the typical smooth surface of a synthetic fiber does not replicate the micro‐ and nanofeatures observed in vivo, which guide and regulate cell behavior. In this study, a method to fabricate photocrosslinkable cell‐responsive methacrylamide‐modified gelatin (GelMA) fibers with exquisite microstructured surfaces by using a microfluidic device is developed. These hydrogel fibers with microgrooved surfaces efficiently promote cell encapsulation and adhesion. GelMA fibers significantly promote the viability of cells encapsulated in/or grown on the fibers compared with similar grooved alginate fibers used as controls. Importantly, the grooves engraved on the GelMA fibers induce cell alignment. Furthermore, the GelMA fibers exhibit excellent processability and could be wound into various shapes. These microstructured GelMA fibers have great potential as templates for the creation of fiber‐shaped tissues or tissue microstructures.  相似文献   

4.
Hydrogels have been applied to improve stem cell therapy and drug delivery, but current hydrogel‐based delivery methods are inefficient in clinical settings due to difficulty in handling and treatment processes, and low off‐the‐shelf availability. To overcome these limitations, an adhesive hyaluronic acid (HA) hydrogel patch is developed that acts as a ready‐to‐use tissue tape for therapeutic application. The HA hydrogel patches functionalized with phenolic moieties (e.g., catechol, pyrogallol) exhibit stronger tissue adhesiveness, greater elastic modulus, and increased off‐the‐shelf availability, compared with their bulk solution gel form. With this strategy, stem cells are efficiently engrafted onto beating ischemic hearts without injection, resulting in enhanced angiogenesis in ischemic regions and improving cardiac functions. HA hydrogel patches facilitate the in vivo engraftment of stem cell–derived organoids. The off‐the‐shelf availability of the hydrogel patch is also demonstrated as a drug‐loaded ready‐made tissue tape for topical drug delivery to promote wound healing. Importantly, the applicability of the cross‐linker‐free HA patch is validated for therapeutic cell and drug delivery. The study suggests that bioinspired phenolic adhesive hydrogel patches can provide an innovative method for simple but highly effective cell and drug delivery, increasing the off‐the‐shelf availability—a critically important component for translation to clinical settings.  相似文献   

5.
Precise neural electrical stimulation, which is a means of promoting neuronal regeneration, is a promising solution for patients with neurotrauma and neurodegenerative diseases. In this study, wirelessly controllable targeted motion and precise stimulation at the single‐cell level using S.platensis@Fe3O4@tBaTiO3 micromotors are successfully demonstrated for the first time. A highly versatile and multifunctional biohybrid soft micromotor is fabricated via the integration of S.platensis with magnetic Fe3O4 nanoparticles and piezoelectric BaTiO3 nanoparticles. The results show that this micromotor system can achieve navigation in a highly controllable manner under a low‐strength rotating magnetic field. The as‐developed system can achieve single‐cell targeted motion and then precisely induce the differentiation of the targeted neural stem‐like cell by converting ultrasonic energy to an electrical signal in situ owing to the piezoelectric effect. This new approach toward the high‐precision stimulation of neural stem‐like cells opens up new applications for micromotors and has excellent potential for precise neuronal regenerative therapies.  相似文献   

6.
Mesenchymal stem cells (MSCs) have been widely used for regenerative therapy. In most current clinical applications, MSCs are delivered by injection but face significant issues with cell viability and penetration into the target tissue due to a limited migration capacity. Some therapies have attempted to improve MSC stability by their encapsulation within biomaterials; however, these treatments still require an enormous number of cells to achieve therapeutic efficacy due to low efficiency. Additionally, while local injection allows for targeted delivery, injections with conventional syringes are highly invasive. Due to the challenges associated with stem cell delivery, a local and minimally invasive approach with high efficiency and improved cell viability is highly desired. In this study, a detachable hybrid microneedle depot (d‐HMND) for cell delivery is presented. The system consists of an array of microneedles with an outer poly(lactic‐co‐glycolic) acid shell and an internal gelatin methacryloyl (GelMA)‐MSC mixture (GMM). The GMM is characterized and optimized for cell viability and mechanical strength of the d‐HMND required to penetrate mouse skin tissue is also determined. MSC viability and function within the d‐HMND is characterized in vitro and the regenerative efficacy of the d‐HMND is demonstrated in vivo using a mouse skin wound model.  相似文献   

7.
Peripheral nerve injuries are serious conditions, and surgical treatment has critical limitations. Therefore, nerve guidance conduits (NGCs) are proposed as an alternative. In this study, multifunctional NGCs are fabricated for the regeneration of injured peripheral nerves. Graphene oxide (GO) and gelatin‐methacrylate (GelMA) are polymerized and chemically reduced to form reduced (GO/GelMA) (r(GO/GelMA)). The prepared materials present good electrical conductivity, flexibility, mechanical stability, and permeability, which are suitable for use as NGCs. In vitro studies show 2.1‐ and 1.4‐fold promotion of neuritogenesis of PC12 neuronal cells on r(GO/GelMA) compared to GelMA and unreduced GO/GelMA, respectively. Animal studies using a rat sciatic nerve injury model with a 10 mm gap between the proximal and distal regions of the defect reveal that r(GO/GelMA) NGCs significantly enhance peripheral nerve regeneration, indicated by improved muscle weight increase, electro‐conduction velocity, and sciatic nerve function index. Specifically, r(GO/GelMA) NGCs are utilized to potentiate regrowth with myelination in rat sciatic nerves followed by histological, immunohistological, and morphometrical analyses. This study successfully shows the feasibility of electrically conductive hydrogel NGCs as functional conduits for improved nerve regeneration in a preclinical study, where these NGCs can not only mimic nerve tissues but also strongly promote nerve regeneration.  相似文献   

8.
Novel poly(N‐isopropylacrylamide)‐clay (PNIPAM‐clay) nanocomposite (NC) hydrogels with both excellent responsive bending and elastic properties are developed as temperature‐controlled manipulators. The PNIPAM‐clay NC structure provides the hydrogel with excellent mechanical property, and the thermoresponsive bending property of the PNIPAM‐clay NC hydrogel is achieved by designing an asymmetrical distribution of nanoclays across the hydrogel thickness. The hydrogel is simply fabricated by a two‐step photo polymerization. The thermoresponsive bending property of the PNIPAM‐clay NC hydrogel is resulted from the unequal forces generated by the thermoinduced asynchronous shrinkage of hydrogel layers with different clay contents. The thermoresponsive bending direction and degree of the PNIPAM‐clay NC hydrogel can be adjusted by controlling the thickness ratio of the hydrogel layers with different clay contents. The prepared PNIPAM‐clay NC hydrogels exhibit rapid, reversible, and repeatable thermoresponsive bending/unbending characteristics upon heating and cooling. The proposed PNIPAM‐clay NC hydrogels with excellent responsive bending property are demonstrated as temperature‐controlled manipulators for various applications including encapsulation, capture, and transportation of targeted objects. They are highly attractive material candidates for stimuli‐responsive “smart” soft robots in myriad fields such as manipulators, grippers, and cantilever sensors.  相似文献   

9.
Direct injection is a minimally invasive method of stem cell transplantation for numerous injuries and diseases. However, despite its promising potential, its clinical translation is difficult due to the low cell retention and engraftment after injection. With high versatility, high‐resolution control and injectability, microfabrication of stem‐cell laden biomedical hydrogels holds great potential as minimally invasive technology. Herein, a strategy of microfluidics‐assisted technology entrapping bone marrow‐derived mesenchymal stem cells (BMSCs) and growth factors in photocrosslinkable gelatin (GelMA) microspheres to ultimately generate injectable osteogenic tissue constructs is presented. Additionally, it is demonstrated that the GelMA microspheres can sustain stem cell viability, support cell spreading inside the microspheres and migration from the interior to the surface as well as enhance cell proliferation. This finding shows that encapsulated cells have the potential to directly and actively participate in the regeneration process. Furthermore, it is found that BMSCs encapsulated in GelMA microspheres show enhanced osteogenesis in vitro and in vivo, associated with a significant increase in mineralization. In short, the proposed strategy can be utilized to facilitate bone regeneration with minimum invasiveness, and can potentially be applied along with other matrices for extended applications.  相似文献   

10.
3D printing technology has been widely explored for the rapid design and fabrication of hydrogels, as required by complicated soft structures and devices. Here, a new 3D printing method is presented based on the rheology modifier of Carbomer for direct ink writing of various functional hydrogels. Carbomer is shown to be highly efficient in providing ideal rheological behaviors for multifunctional hydrogel inks, including double network hydrogels, magnetic hydrogels, temperature‐sensitive hydrogels, and biogels, with a low dosage (at least 0.5% w/v) recorded. Besides the excellent printing performance, mechanical behaviors, and biocompatibility, the 3D printed multifunctional hydrogels enable various soft devices, including loadable webs, soft robots, 4D printed leaves, and hydrogel Petri dishes. Moreover, with its unprecedented capability, the Carbomer‐based 3D printing method opens new avenues for bioprinting manufacturing and integrated hydrogel devices.  相似文献   

11.
Single wall carbon nanotube (SWNT) based thermo‐sensitive hydrogel (SWNT‐GEL) is reported, which provides an injectable drug delivery system as well as a medium for photothermal transduction. SWNT‐hydrogel alone appears to be nontoxic on gastric cancer cells (BGC‐823 cell line) but leads to cell death with NIR radiation through a hyperthermia proapoptosis mechanism. By incorporating hyperthermia therapy and controlled in situ doxorubicin (DOX) release, DOX‐loaded SWNT‐hydrogel with NIR radiation proves higher tumor suppression rate on mice xenograft gastric tumor models compared to free DOX without detectable organ toxicity. The developed system demonstrates improved efficacy of chemotherapeutic drugs which overcomes systemic adverse reactions and presents immense potential for gastric cancer treatment.  相似文献   

12.
Wearable and implantable bioelectronics are receiving a great deal of attention because they offer huge promise in personalized healthcare. Currently available bioelectronics generally rely on external aids to form an attachment to the human body, which leads to unstable performance in practical applications. Self‐adhesive bioelectronics are highly desirable for ameliorating these concerns by offering reliable and conformal contact with tissue, and stability and fidelity in the signal detection. However, achieving adequate and long‐term self‐adhesion to soft and wet biological tissues has been a daunting challenge. Recently, mussel‐inspired hydrogels have emerged as promising candidates for the design of self‐adhesive bioelectronics. In addition to self‐adhesiveness, the mussel‐inspired chemistry offers a unique pathway for integrating multiple functional properties to all‐in‐one bioelectronic devices, which have great implications for healthcare applications. In this report, the recent progress in the area of mussel‐inspired self‐adhesive bioelectronics is highlighted by specifically discussing: 1) adhesion mechanism of mussels, 2) mussel‐inspired hydrogels with long‐term and repeatable adhesion, 3) the recent advance in development of hydrogel bioelectronics by reconciling self‐adhesiveness and additional properties including conductivity, toughness, transparency, self‐healing, antibacterial properties, and tolerance to extreme environment, and 4) the challenges and prospects for the future design of the mussel‐inspired self‐adhesive bioelectronics.  相似文献   

13.
A novel biocompatible polysaccharide‐based self‐healing hydrogel, CEC‐l‐OSA‐l‐ADH hydrogel (“l” means “linked‐by”), is developed by exploiting the dynamic reaction of N‐carboxyethyl chitosan (CEC) and adipic acid dihydrazide (ADH) with oxidized sodium alginate (OSA). The self‐healing ability, as demonstrated by rheological recovery, macroscopic observation, and beam‐shaped strain compression measurement, is attributed to the coexistence of dynamic imine and acylhydrazone bonds in the hydrogel networks. The CEC‐l‐OSA‐l‐ADH hydrogel shows excellent self‐healing ability under physiological conditions with a high healing efficiency (up to 95%) without need for any external stimuli. In addition, the CEC‐l‐OSA‐l‐ADH hydrogel exhibits good cytocompatibility and cell release as demonstrated by three‐dimensional cell encapsulation. With these superior properties, the developed hydrogel holds great potential for applications in various biomedical fields, e.g., as cell or drug delivery carriers.  相似文献   

14.
Biohybrid soft robotic devices present unique advantages for designing biologically active machines that can dynamically sense and interact with complex bioelectrical signals. Here, a controllable cell‐based machine is developed that harvests energy from arrays of beating cardiomyocytes to generate electricity for biomedical microscale robotic applications. The “Cell Generator” device is based on an array of piezoelectric microcantilevers wrapped with 3D patterned cardiac cells. Spontaneous contraction of the engineered cardiac constructs provides the source of mechanical energy for electricity generation. It is demonstrated that a single “Cell Generator” unit with 40 cantilevers can output peak voltages of ≈70 mV, and a larger array of 540 cantilevers can directly generate a pulsed output as high as ≈1 V. When integrated with an electrical rectification and storage circuit, it is further shown that the “Cell Generator” can provide functional outputs and work as a self‐powered neural stimulator to evoke action potentials in cultured neuronal networks. This demonstration of “Cell Generator” technology provides an innovative perspective of exploiting live biological powering system on biomedical microscale robotic devices in the human body.  相似文献   

15.
Botanical systems have evolved the intriguing ability to respond to diverse stimuli due to long‐term survival competition. Mimicking these dynamic behaviors has greatly advanced the developments in wide fields ranging from soft robotics, precision sensors to drug delivery and biomedical devices. However, realization of stimuli‐responsive components at the microscale with high response speed still remains a significant challenge. Herein, the miniature biomimetic 4D printing of pH‐responsive hydrogel is reported in spatiotemporal domain by femtosecond laser direct writing. The dimension of the printed architectures is at the microscale (<102 µm) and the response speed is reduced down to subsecond level (<500 ms). Shape transformation with multiple degrees of freedom is accomplished by taking advantage of pH‐triggered expansion, contraction, and torsion. Biomimetic complex shape‐morphing is enabled by adopting flexible scanning strategies. In addition, application of this 4D‐printed micro‐architecture in selective micro‐object trapping and releasing is demonstrated, showcasing its possibilities in micromanipulation, single‐cell analysis, and drug delivery.  相似文献   

16.
Development of efficient, low‐cost, and durable electrocatalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is of significant importance for many electrochemical devices, such as rechargeable metal–air batteries, fuel cells, and water electrolyzers. Here, a novel approach for the synthesis of a trifunctional electrocatalyst derived from iron/cobalt‐containing polypyrrole (PPy) hydrogel is reported. This strategy relies on the formation of a supramolecularly cross‐linked PPy hydrogel that allows for efficient and homogeneous incorporation of highly active Fe/Co–N–C species. Meanwhile, Co nanoparticles are also formed and embedded into the carbon scaffold during the pyrolysis process, further promoting electrochemical activities. The resultant electrocatalyst exhibits prominent catalytic activities for ORR, OER, and HER, surpassing previously reported trifunctional electrocatalysts. Finally, it is demonstrated that the as‐obtained trifunctional electrocatalyst can be used for electrocatalytic overall water splitting in a self‐powered manner under ambient conditions. This work offers new prospects in developing highly active, nonprecious‐metal‐based electrocatalysts in electrochemical energy devices.  相似文献   

17.
Due to its simplicity, versatility, and high efficiency, the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 technology has emerged as one of the most promising approaches for treatment of a variety of genetic diseases, including human cancers. However, further translation of CRISPR/Cas9 for cancer gene therapy requires development of safe approaches for efficient, highly specific delivery of both Cas9 and single guide RNA to tumors. Here, novel core–shell nanostructure, liposome‐templated hydrogel nanoparticles (LHNPs) that are optimized for efficient codelivery of Cas9 protein and nucleic acids is reported. It is demonstrated that, when coupled with the minicircle DNA technology, LHNPs deliver CRISPR/Cas9 with efficiency greater than commercial agent Lipofectamine 2000 in cell culture and can be engineered for targeted inhibition of genes in tumors, including tumors the brain. When CRISPR/Cas9 targeting a model therapeutic gene, polo‐like kinase 1 (PLK1), is delivered, LHNPs effectively inhibit tumor growth and improve tumor‐bearing mouse survival. The results suggest LHNPs as versatile CRISPR/Cas9‐delivery tool that can be adapted for experimentally studying the biology of cancer as well as for clinically translating cancer gene therapy.  相似文献   

18.
Bacteria‐inspired magnetic helical micro‐/nanoswimmers can be actuated and steered in a fuel‐free manner using a low‐strength rotating magnetic field, generating remotely controlled 3D locomotion with high precision in a variety of biofluidic environments. They are therefore envisioned for biomedical applications related to targeted diagnosis and therapy. In this article, a porous hollow microswimmer possessing an outer shell aggregated by mesoporous spindle‐like magnetite nanoparticles (NPs) and a helical‐shaped inner cavity is proposed. The fabrication is straightforward via a cost‐effective mass‐production process of biotemplated synthesis using helical microorganisms. Here, Spirulina‐based fabrication is demonstrated as an example. The fabricated microswimmers are superparamagnetic and exhibit low cytotoxicity. They are also capable of performing structural disassembly to form individual NPs using ultrasound when needed. For the first time in the literature of helical microswimmers, a porous hollow architecture is successfully constructed, achieving an ultrahigh specific surface area for surface functionalization and enabling diffusion‐based cargo loading/release. Furthermore, experimental and analytical results indicate better swimming performance of the microswimmers than the existing non‐hollow helical micromachines of comparable sizes and dimensions. These characteristics of the as‐proposed microswimmers suggest a novel microrobotic tool with high loading capacity for targeted delivery of therapeutic/imaging agents in vitro and in vivo.  相似文献   

19.
Fiber bundles are present in many tissues throughout the body. In most cases, collagen subunits spontaneously self‐assemble into a fibrilar structure that provides ductility to bone and constitutes the basis of muscle contraction. Translating these natural architectural features into a biomimetic scaffold still remains a great challenge. Here, a simple strategy is proposed to engineer biomimetic fiber bundles that replicate the self‐assembly and hierarchy of natural collagen fibers. The electrostatic interaction of methacrylated gellan gum with a countercharged chitosan polymer leads to the complexation of the polyelectrolytes. When directed through a polydimethylsiloxane channel, the polyelectrolytes form a hierarchical fibrous hydrogel demonstrating nanoscale periodic light/dark bands similar to D‐periodic bands in native collagen and align parallel fibrils at microscale. Importantly, collagen‐mimicking hydrogel fibers exhibit robust mechanical properties (MPa scale) at a single fiber bundle level and enable encapsulation of cells inside the fibers under cell‐friendly mild conditions. Presence of carboxyl‐ (in gellan gum) or amino‐ (in chitosan) functionalities further enables controlled peptide functionalization such as Arginylglycylaspartic acid (RGD) for biochemical mimicry (cell adhesion sites) of native collagen. This biomimetic‐aligned fibrous hydrogel system can potentially be used as a scaffold for tissue engineering as well as a drug/gene delivery vehicle.  相似文献   

20.
Artificial micro‐/nanoswimmers have various potential applications including minimally invasive diagnosis and targeted therapies, environmental sensing and monitoring, cell manipulation and analysis, and lab‐on‐a‐chip devices. Inspired by natural motile bacteria such as E. Coli, artificial bacterial flagella (ABFs) are one kind of magnetic helical microswimmers. ABFs can perform 3D navigation in a controllable fashion with micrometer precision under low‐strength rotating magnetic fields (<10 mT) and are promising tools for targeted drug delivery in vitro and in vivo. In this work, the successful wirelessly targeted and single‐cell gene delivery to human embryonic kidney (HEK 293) cells using ABFs loaded with plasmid DNA (pDNA) in vitro is demonstrated for the first time. The ABFs are functionalized with lipoplexes containing pDNA to generate functionalized ABFs (f‐ABFs). The f‐ABFs are steered wirelessly by low‐strength rotating magnetic fields and deliver the loaded pDNA into targeted cells. The cells targeted by f‐ABFs are successfully transfected by the transported pDNA and expressed the encoding protein. These f‐ABFs may also be useful for in vivo gene delivery and other applications such as sensors, actuators, cell biology, and lab‐on‐a‐chip environments.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号