Search

This work presents anodically electrodeposited copper (Cu)/chitosan gel as a novel precursor for synthesizing a Cu/carbon nanocomposite through laser-induced carbonization. Metal/carbon nanocomposites offering advantageous properties compared to their individual counterparts stand out in various applications, particularly in those involving electrochemical phenomena. However, their synthesis often suffers from complicated and time-consuming synthesis procedures. Here, we integrate anodic electrodeposition and laser-induced carbonization to yield a rapid, simple, and inexpensive procedure for synthesizing metal/carbon nanocomposite. A precursor composite involving Cu-coordinated chitosan film is achieved through anodic electrodeposition on a copper anode. Irradiation by an infrared laser with optimized parameters results in the thermochemical decomposition of the Cu/chitosan composite, rapidly forming a nanocomposite material featuring highly graphitized and porous carbon materials. Elemental mapping confirms the formation of the nanocomposite, although no crystalline phases of copper are observed during X-ray diffraction. This can be attributed to the rapid nature of the laser-carbonization process. The nanocomposite material is further demonstrated for electrochemical sensing of hydrogen peroxide (H2O2), exhibiting a sensitivity of 2.65 mM−1 for concentrations ranging from 0.01 mM to 0.1 mM H2O2, and 0.01 ± 0.01 mM−1 for concentrations from 0.1 to 10 mM H2O2. These sensitivities are comparable to other non-enzymatic H2O2 biosensors. The finding of this work signifies a rapid and facile method for synthesizing metal/carbon nanocomposites with strong implications for the field of biosensors. [ABSTRACT FROM AUTHOR]

In tissue engineering, the pivotal role of scaffolds is underscored, serving as key elements to emulate the native extracellular matrix. These scaffolds must provide structural integrity and support and supply electrical, mechanical, and chemical cues for cell and tissue growth. Notably, electrical conductivity plays a crucial role when dealing with tissues like bone, spinal, neural, and cardiac tissues. However, the typical materials used as tissue engineering scaffolds are predominantly polymers, which generally characteristically feature poor electrical conductivity. Therefore, it is often necessary to incorporate conductive materials into the polymeric matrix to yield electrically conductive scaffolds and further enable electrical stimulation. Among different conductive materials, carbon nanomaterials have attracted significant attention in developing conductive tissue engineering scaffolds, demonstrating excellent biocompatibility and bioactivity in both in vitro and in vivo settings. This article aims to comprehensively review the current landscape of carbon‐based conductive scaffolds, with a specific focus on their role in advancing tissue engineering for the regeneration and maturation of functional tissues, emphasizing the application of electrical stimulation. This review highlights the versatility of carbon‐based conductive scaffolds and addresses existing challenges and prospects, shedding light on the trajectory of innovative conductive scaffold development in tissue engineering. [ABSTRACT FROM AUTHOR]

This study presents a novel approach for investigating the shrinkage dynamics of 3D‐printed nanoarchitectures during isothermal pyrolysis, utilizing in situ electron microscopy. For the first time, the temporal evolution of 3D structures is tracked continuously until a quasi‐stationary state is reached. By subjecting the 3D objects to different temperatures and atmospheric conditions, significant changes in the resulting kinetic parameters and morphological textures of the 3D objects are observed, particularly those possessing varying surface‐to‐volume ratios. Its results reveal that the effective activation energy required for pyrolysis‐induced morphological shrinkage is approximately four times larger under vacuum conditions than in a nitrogen atmosphere (2.6 eV vs. 0.5–0.9 eV, respectively). Additionally, a subtle enrichment of oxygen on the surfaces of the structures for pyrolysis in nitrogen is found through a postmortem electron energy loss spectroscopy study, differentiating the vacuum pyrolysis. These findings are examined in the context of the underlying process parameters, and a mechanistic model is proposed. As a result, understanding and controlling pyrolysis in 3D structures of different geometrical dimensions not only enables precise modification of shrinkage and the creation of tensegrity structures, but also promotes pyrolytic carbon development with custom architectures and properties, especially in the field of carbon micro‐ and nano‐electromechanical systems. [ABSTRACT FROM AUTHOR]

Additive micro/nano‐manufacturing of polymeric precursors combining with a subsequent pyrolysis step enables the design‐controlled fabrication of micro/nano‐architected 3D pyrolytic carbon structures with complex architectural details. Pyrolysis results in a significant geometrical shrinkage of the pyrolytic carbon structure, leading to a structural dimension significantly smaller than the resolution limit of the involved additive manufacturing technology. Combining with the material properties of carbon and 3D architectures, architected 3D pyrolytic carbon exhibits exceptional properties, which are significantly superior to that of bulk carbon materials. This article presents a comprehensive review of the manufacturing processes of micro/nano‐architected pyrolytic carbon materials, their properties, and corresponding demonstrated applications. Acknowledging the "young" age of the field of micro/nano‐architected carbon, this article also addresses the current challenges and paints the future research directions of this field. [ABSTRACT FROM AUTHOR]

Based on the rapid advances in additive manufacturing, micro‐patterned heterostructures of soft materials have become available that need to be characterized down to the nanoscale. Advanced function‐structure relationships are designed by direct 3D structuring of the object and – in the future – fine control over material functionality in 3D will produce complex functional objects. To control their design, fabrication and final structure, morphological and spectroscopical imaging in 3D at nanometer resolution are critically required. With examples of carbon‐based objects, it is demonstrated how serial ultramicrotomy, that is, cutting a large number of successive ultrathin sections, can be utilized to gain access to the interior of 3D objects. Array tomography, hierarchical imaging and correlative light and electron microscopy can bridge length scales over several orders of magnitude and provide multimodal information of the sample's inner structure. Morphology data derived from scanning electron microscopy are correlated with spectroscopy in analytical transmission electron microscopy and probe microscopy at nanometer resolution, using TEM‐electron energy loss spectroscopy and infrared‐scanning‐near‐field microscopy. The correlation of different imaging modalities and spectroscopy of carbon‐based materials in 3D provides a powerful toolbox of complementary techniques for understanding emerging functions from nanoscopic structuring. [ABSTRACT FROM AUTHOR]

Electrospinning is a prominent technique for micro/nanofiber production and has received significant attention in the 21st century. It enables the production of ultrafine fibers using a variety of polymers, including synthetic, natural, and hybrid materials. Electrospun nanofibers (NFs) possess unique properties such as a high surface‐to‐volume ratio, tunable pore structures, and customizable composition, making them highly desirable in various fields such as biomedical science, textiles, sensors, filters, energy, and packaging. Herein, particular attention will be given to the application of NFs in biomedical fields. The use of NFs for the delivery of drugs, growth factors, proteins, nanoparticles, etc., holds significant promise in the field of biomedical science. To combine these compounds with NFs, various electrospinning techniques have been developed with outstanding improvements, and based on the requirements of the application type, different electrospinning processes are favored. In this review, the most common drug loading methods into NFs, generally used synthetic/natural polymers for NF production, and their application in drug delivery systems, tissue engineering, and wound dressing will be mentioned. Finally, challenges and future perspectives for above mentioned biomedical applications are discussed. [ABSTRACT FROM AUTHOR]