Electrospinning is an important technique to fabricate nanofibers. In recent years, near-field electrospinning (NFES) has been developed to enhance the control of nanofiber deposition compared to conventional electrospinning, achieved by reducing the operating distance and electric field. This enables the construction of high-aspect ratio 3D structures in a self-aligned, layer-by-layer manner. However, the alignment of fiber deposition can be hindered by charge accumulation in the polymer fibers. Furthermore, a theoretical understanding of the underlying fiber deposition mechanism is still lacking. Herein, we present a numerical model for studying the charge transport, dissipation, and accumulation of NFES polymer fiber deposition. The model reveals that the presence of a trapped state in polymeric materials imposes limitations on the quality of charged fiber deposition. Moreover, the effect of different substrate materials on charge dissipation in fiber deposition is studied. To validate the model, we compare the simulation results with NFES experiments, demonstrating qualitative agreement. We also analyze the effect of the fiber materials and experimental parameters on the printing quality. This model provides an approach to analyze and optimize the operating parameters of NFES to achieve precise and stable nanofiber deposition.

Near‐field electrospinning (NFES) holds the potential to develop into a versatile additive nanomanufacturing platform. However, the impact of a variety of processing variables remains unresolved.Herein, the effect of solvents used to prepare suitable solutions for 3D microstructuring by electrospinning is studied. 3D straight walls of stacked fibers are fabricated using a layer‐by‐layer fiber deposition approach. The effect of the choice of substrate material is also explored. The results show that a high vapor pressure, and a low dielectric constant of the solvent, as well as a high substrate conductivity facilitate improved stacking of fiber layers. Utilizing these conditions, 3D stacked walls of polyethylene oxide are fabricated, and a maximum aspect ratio of 191.7 ± 52.6, while using a chromium/gold substrate and dichloromethane/methanol as the solvent is achieved.

This work establishes carbon nanofibre-mediated patterning of metal oxide nanostructures, through the combination of electrospinning and vapor-phase transport growth. Electrospinning of a suitable precursor with subsequent carbonization results in the patterning of catalyst gold nanoparticles embedded within carbon nanofibres. During vapor-phase transport growth, these nanofibres allow preferential growth of one-dimensional metal oxide nanostructures, which grow radially outward from the nanofibril axis, yielding a hairy caterpillar-like morphology. The synthesis of metal oxide caterpillars is demonstrated using zinc oxide, indium oxide, and tin oxide. Source and substrate temperatures play the most crucial role in determining the morphology of the metal oxide caterpillars, whereas the distribution of the nanofibres also has a significant impact on the overall morphology. Introducing the current methodology with near-field electrospinning further facilitates user-defined custom patterning of metal oxide caterpillar-like structures.

A biosensor is an analytical device which recognizes a biological substance and converts the recognition into a measurable or readable signal. Since the first development in 1962 by Leland C. Clark, biosensors have been a hot topic in research communities. Biosensors have a huge impact on healthcare diagnostics, as well as on the monitoring and pharmaceutical industries. Rapid detection, portability, and the low cost of biosensors have been proved an essential step in the decentralization of clinical applications, by bringing emergency-room screening to self-testing at home.

Multiscale 3D carbon architectures are of particular interest in tissue engineering applications, as these structures may allow for three-dimensional cell colonization essential for tissue growth. In this work, carbon fiber/microlattice hybrid architectures are introduced as innovative multi-scale scaffolds for tissue engineering. The microlattice provides the design freedom and structural integrity, whereas the fibrous component creates a cellular microenvironment for cell colonization. The hybrid structures are fabricated by carbonization of stereolithographically 3D printed epoxy microlattice architectures which are pre-filled with cotton fibers within the empty space of the architectures. The cotton filling result in less shrinkage of the architecture during carbonization, as the tight confinement of the fibrous material prevents the free-shrinkage of the microlattices. The hybrid architecture exhibits a compressive strength of 156.9±25.6 kPa, which is significantly higher than an empty carbon microlattice architecture. Furthermore, the hybrid architecture exhibits a flexible behavior up to 30% compressive strain, which is also promising towards soft-tissue regeneration. Osteoblast-like murine MC3T3-E1 cells are cultured within the 3D hybrid structures. Results show that the cells are able to not only proliferate on the carbon microlattice elements as well as along the carbon fibers, but also make connections with each other across the inner pores created by the fibers, leading to a three-dimensional cell colonization. These carbon fiber/microlattice hybrid structures are promising for future fabrication of functionally graded scaffolds for tissue repair applications.