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Microneedles, which are small needle-shaped devices, have gained attention as versatile tools with applications across various fields owing to their precision and minimal invasiveness. In the literature, the integration of microneedle technology into agricultural domains has been explored, particularly focusing on the real-time monitoring of precise agrochemical delivery and crop biosensing in situ. In this study, we summarize representative microneedle types and corresponding fabrication techniques. Then, we discuss the advantages of microneedles in plant health management and drug delivery, as well as related challenges, such as safety and mass production. The agricultural applications of microneedles can potentially overcome the limitations of traditional methods and offer innovative solutions for crop disease management. This study demonstrates that microneedles present innovative possibilities in agriculture and contribute to the improvement of sustainable agriculture.

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Over the past few decades, hydrogels have attracted considerable attention as promising biomedical materials. However, conventional hydrogels require improved mechanical properties, such as brittleness, which significantly limits their widespread use. Recently, hydrogels with remarkably improved toughness have been developed; however, their low biocompatibility must be addressed. In this study, we developed a tough graphene hybrid hydrogel with nanostructures. The resultant hydrogel exhibited remarkable mechanical properties while representing an aligned nanostructure that resembled the extracellular matrix of soft tissue. Owing to the synergistic effect of the topographical properties, and the enhanced biochemical properties, the graphene hybrid hydrogel had excellent stretchability, resilience, toughness, and biocompatibility. Furthermore, the hydrogel displayed outstanding tissue regeneration capabilities (e.g., skin and tendons). Overall, the proposed graphene hybrid tough hydrogel may provide significant insights into the application of tough hydrogels in tissue regeneration.

Bone regeneration remains a critical concern across diverse medical disciplines, because it is a complex process that requires a combinatorial approach involving the integration of mechanical, electrical, and biological stimuli to emulate the native cellular microenvironment. In this context, piezoelectric scaffolds have attracted considerable interest owing to their remarkable ability to generate electric fields in response to dynamic forces. Nonetheless, the application of such scaffolds in bone tissue engineering has been limited by the lack of a scaffold that can simultaneously provide both the intricate electromechanical environment and the biocompatibility of the native bone tissue. Here, we present a pioneering biomimetic scaffold that combines the unique properties of piezoelectric and topographical enhancement with the inherent osteogenic abilities of hydroxyapatite (HAp). Notably, the novelty of this work lies in the incorporation of HAp into polyvinylidene fluoride-co-trifluoro ethylene in a freestanding form, leveraging its natural osteogenic potential within a piezoelectric framework. Through comprehensive in vitroand in vivoinvestigations, we demonstrate the remarkable potential of these scaffolds to accelerate bone regeneration. Moreover, we demonstrate and propose three pivotal mechanisms─(i) electrical, (ii) topographical, and (iii) paracrine─that collectively contribute to the facilitated bone healing process. Our findings present a synergistically derived biomimetic scaffold design with wide-ranging prospects for bone regeneration as well as various regenerative medicine applications.

Background:: Gelatin, a natural polymer, has a number of advantages as a material for fabricating nanoparticles, such as its hydrophilicity, biodegradability, nontoxicity, and biocompatibility, as well as low cost. Despite these various advantages, gelatin-based nanoparticles still have critical limitation for biomedical applications due to their relatively larger size than those of other materials. Methods:: In this study, a new strategy to design and fabricate small gelatin nanoparticles (GNPs) was proposed. The technique was based on the natural phenomenon where with decreasing temperature, the compression between the molecules of substances increases and the volume shrinks. Results:: The average size of the fabricated small GNPs was less than 100 nm and their gelatin properties (including non-cytotoxicity) were well maintained. The drug release profiles of the GNPs were confirmed, for which a simple mathematical model based on the conventional diffusion equation was proposed. There was a burst of drug release in the first 3 days, with different release profiles according to the concentration of model drugs loaded onto the GNPs. It was also demonstrated that the drug release profiles of the proposed mathematical model were consistent with the experimental results. Conclusion:: Our work proposes that these small GNPs could be used as efficient drug and gene delivery and tissue engineering platforms for various biomedical applications.

Inner ear organoids (IEOs) are 3D structures grown in vitro, which can mimic the complex cellular structure and function of the inner ear. IEOs are potential solutions to problems related to inner ear development, disease modeling, and drug delivery. However, current approaches in generating IEOs using chemical factors have a few limitations, resulting in unpredictable outcomes. In this study, we propose the use of nanomaterial-based approaches, specifically by using graphene oxide (GO). GO’s unique properties promote cell–extracellular matrix interactions and cell–cell gap junctions, thereby enhancing hair cell formation, which is an essential part of IEO development. We also investigated the potential applications for drug testing. Our findings suggest that GO is a promising candidate for enhancing the functionality of IEOs and advancing our understanding of the problems underlying inner ear development. The use of nanomaterial-based approaches may provide a more reliable and effective method for building better IEOs in the future.

Nanoscale biomaterials have garnered immense interest in the scientific community in the recent decade. This review specifically focuses on the application of three nanomaterials, i.e., graphene and its derivatives (graphene oxide, reduced graphene oxide), carbon nanotubes (CNTs) and nanocellulose (cellulose nanocrystals or CNCs and cellulose nanofibers or CNFs), in regenerating different types of tissues, including skin, cartilage, nerve, muscle and bone. Their excellent inherent (and tunable) physical, chemical, mechanical, electrical, thermal and optical properties make them suitable for a wide range of biomedical applications, including but not limited to diagnostics, therapeutics, biosensing, bioimaging, drug and gene delivery, tissue engineering and regenerative medicine. A state-of-the-art literature review of composite tissue scaffolds fabricated using these nanomaterials is provided, including the unique physicochemical properties and mechanisms that induce cell adhesion, growth, and differentiation into specific tissues. In addition, in vitroand in vivocytotoxic effects and biodegradation behavior of these nanomaterials are presented. We also discuss challenges and gaps that still exist and need to be addressed in future research before clinical translation of these promising nanomaterials can be realized in a safe, efficacious, and economical manner.

Exosomes are nanovesicles surrounded by a plasma membrane and carry bioactive molecules (e.g., proteins, lipids, and nucleic acids) of the origin cell type. The bioactive molecules delivered by exosomes to the recipient cells have attracted considerable attention, as they play an important role in intercellular communication. Moreover, exosomes have unique properties, including the ability to penetrate the biological barrier with minimal immunogenicity and side effects, which can influence various physiological and pathological processes. Thus, exosomes are a promising therapeutic platform for various diseases (e.g., malignancies and allergies), as well as for the regeneration of damaged tissues. However, challenges of obtaining exosomes, such as complex extraction procedures, low yield, and difficulty in quantification are yet to be overcome, which limits the use of exosomes in clinical settings. In this review, we describe the state-of-the-art engineering techniques and strategies for highly efficient mass production of exosomes. Moreover, we discuss the functional aspects and potential therapeutic applications of stem cell-derived exosomes, and deliberate upon various engineering techniques and platform combinations for improved tissue regeneration by exosomes.

Purpose: Over the past decade, cultured meat has attracted considerable attention as a sustainable alternative. Mimicking highly aligned muscle tissues and adipose tissues to replicate real meat poses a significant challenge to the development of cultured meat. Recently, techniques involving co-culture or post-assembly of different types of tissues have been introduced for cultured meat production. However, there is a need for a more straightforward approach for simultaneously replicating muscle and fat tissues. Methods: In this study, we developed nano-cultured meat that recapitulates the structural and physiological characteristics of real meat. GelMA was dissolved in an oil-in-water emulsion to create a fat bioink, and a fat scaffold was fabricated using a digital light processing-based 3D printer. Subsequently, the empty spaces within the fat scaffold were filled with myoblast-laden hydrogel, followed by integration with nanopatterns. Results: The resultant nano-cultured meat not only mimics highly aligned muscle tissue similar to real meat but also allows for the tunable reproduction of fat tissue. Conclusion: Overall, the proposed nano-cultured meat offers valuable insights for achieving a high level of maturity and developing customizable next-generation cultured meat.

Three-dimensional (3D) stem cell culture systems have attracted considerable attention as a way to better mimic the complex interactions between individual cells and the extracellular matrix (ECM) that occur in vivo. Moreover, 3D cell culture systems have unique properties that help guide specific functions, growth, and processes of stem cells (e.g., embryogenesis, morphogenesis, and organogenesis). Thus, 3D stem cell culture systems that mimic in vivoenvironments enable basic research about various tissues and organs. In this review, we focus on the advanced therapeutic applications of stem cell-based 3D culture systems generated using different engineering techniques. Specifically, we summarize the historical advancements of 3D cell culture systems and discuss the therapeutic applications of stem cell-based spheroids and organoids, including engineering techniques for tissue repair and regeneration.

Polymer-based nanocomposites emerged in the 1960s as a groundbreaking approach to advanced materials. By incorporating robust, durable, and multifunctional nanomaterials into a polymer matrix, the performance of nanocomposites has significantly surpassed that of the base polymers. However, over the past six decades, the challenges of achieving uniform nanomaterial dispersion and the resulting non-uniform properties have impeded further progress in this field. Here, we present a polymer-based nanocomposite with highly dispersed nanomaterials, achieved through aerosol-jet-based multi-material three-dimensional (AM3D) printing. This method allows precise programming of the nanocomposite's composition, structure, and dispersity. Numerical simulations in the design of AM3D printing system facilitate the avoidance of interfacial compatibility issue among heterogeneous aerosols, enabling distributed printing without nanomaterial agglomeration. As a result of this high level of dispersion and distribution, the 3D structured nanocomposite exhibits a uniform dielectric constant and low dielectric loss across the entire printed area. This work establishes an engineering framework for defect-free nanocomposites and significantly expands the range of polymer-based multi-material nanocomposite that can be designed and manufactured with complex architectures.

Nanotechnology has facilitated the development of active food packaging systems with functions that could not be achieved by their traditional counterparts. Such smart and active systems can improve the shelf life of perishable products and overcome major bottlenecks associated with the fabrication of safe and environmentally friendly food packaging systems. Herein, we used a plasma-enabled surface modification strategy to fabricate biodegradable and flexible nanoporous polycaprolactone-based (FNP) films for food packaging systems. Their capacity for preserving tomatoes, tangerines, and bananas at room and refrigeration temperatures was tested by analyzing various fruit parameters (mold generation, appearance changes, freshness, weight loss, firmness, and total soluble solids contents). Compared with commonly used polyethylene terephthalate-based containers, the proposed system enhanced the fruit storage quality (i.e., retained appearance, reduced weight loss, better firmness, and sugar contents) by controlling moisture evaporation and inhibiting mold generation. Thus, the FNP film represents a new active food packaging strategy.

Eggshell membrane (ESM)-based biomaterials have generated significant interest for their potential biomedical applications, including those in tissue engineering and regenerative medicine. Herein, the development of a bioactive ESM-based nanopatterned scaffold for enhancing the adhesion and functions of cells has been described. To control the shape of the raw ESM with entangled protein fibers, a two-step dissolution technique is used. Subsequently, nanoimprint lithography is applied to the ESM solution to fabricate scaffolds with a nanotopographic surface inspired by the fiber alignment of the extracellular matrix. In this way, the morphology and proliferation of attached osteoblasts are sensitively controlled through their response to the nanopatterned topography of the prepared scaffold, allowing significant improvements in their osteogenic differentiation and growth factor secretion. This study demonstrates the potential use of this bioactive ESM-based nanopatterned substrate as an effective cell and tissue engineering scaffold.

A microdevice for the measurement of the respiratory activity of cells was fabricated using a microfabricated Clark-type oxygen electrode. The oxygen electrode was completed in a dry state and was activated by introducing water necessary for the reduction of oxygen in the form of water vapor through an oxygen-permeable membrane, which significantly facilitated handling of the device even by nonspecialists. The use of a thin paper layer stabilized the current response and enabled stable continuous operation of the oxygen electrode without current disturbance caused by the evaporation of water. The microdevice was tested in some model experiments including the measurement of the respiratory activity of Escherichia coli(E. coli), evaluation of the efficacy of antibiotics, and measurement of the antibacterial activity of neutrophils, all of which demonstrated that the consumption of dissolved oxygen by cells can be monitored clearly by following an easy procedure for the preparation of the measurements.

Vertically aligned nanomaterials, such as nanowires and nanoneedles, hold strong potential as efficient platforms onto which living cells or tissues can be interfaced for use in advanced biomedical applications. However, their rigid mechanical properties and complex fabrication processes hinder their integration onto flexible, tissue-adaptable, and large-area patch-type scaffolds, limiting their practical applications. In this study, we present a highly flexible patch that possesses a spiky hydrogel nanostructure array as a transplantable platform for enhancing the growth and differentiation of stem cells and efficiently suppressing biofilm formation. In vitrostudies show that the hydrogel nanospike patch imposes a strong physical stimulus to the membranes of stem cells and enhances their osteogenic, chondrogenic, and adipogenic differentiation and the secretion of crucial soluble factors without altering cell viability. At the same time, the array exhibits effective bactericidal properties against Gram-positive and Gram-negative bacteria. In vivostudies further demonstrate that the flexible hydrogel patch with its spiky vertical nanostructures significantly promotes the regeneration of damaged cranial bone tissues while suppressing pathogenic bacterial infections in mouse models.

Cavitation erosion can be observed on hydraulic mechanical devices and has long been studied as a challenging research topic. In this paper, a practical method to predict cavitation erosion was developed. To simulate cavitating flows using computational fluid dynamics (CFD), an isothermal compressible cavitating flow solver was developed using the OpenFOAM toolkit. A cavitation erosion coefficient was proposed as a function of the cavitation and Reynolds numbers. From the simulations, the cavitation erosion coefficients were calculated using metamodeling methods. Finally, the developed practical method of cavitation erosion was applied to a marine propeller. As observed in experiments, cavitation erosion was predicted near the propeller tip.

The micro- and nanoscale structures of biological systems possess various intriguing properties, providing new insights and design principles for the fabrication of engineering platforms. In particular, the unique micro- and nanosurfaces of lotus leaves are highlighted as an emerging strategy that can be used as a tool for the manipulation of superhydrophobicity-based devices. In this review, we provide basic information on lotus leaf surface and present recent advances in micro- and nanoscale engineering platforms inspired by the surface topographies of lotus leaves for various applications. In addition, new perspectives on lotus leaf-inspired functional platforms in various engineering fields are discussed. [ABSTRACT FROM AUTHOR]

Physical and chemical cues, which have emerged as a promising strategy for regulating cellular behaviors, provide important signaling cues to living cells. Neurons are also exposed to distinguishing physical and chemical environments that can greatly influence their behaviors and functions. In this study, we proposed the laminin-coated matrix nanotopography platforms (LMNPs) that generate extracellular physical and chemical cues for neuronal development. Using our platforms, we showed that nanotopographical and biochemical cues could provide suitable environments for neuronal cultures. More importantly, we showed that a LMNPs could control the orientation of neuronal structures as well as accelerate neuronal development through synergistic effects of extracellular nanotopographical and chemical cues. Our study imparts new design principles on the role of nanotopographical and chemical cues in neuronal development for the fabrication of neuroprosthetic scaffolds. [ABSTRACT FROM AUTHOR]

URLLC is a new service category in 5G to accommodate emerging services and applications having stringent latency and reliability requirements. In order to support URLLC, there should be both evolutionary and revolutionary changes in the air interface named 5G NR. In this article, we provide an up-to-date overview of URLLC with an emphasis on the physical layer challenges and solutions in 5G NR downlink. We highlight key requirements of URLLC and then elaborate the physical layer issues and enabling technologies including packet and frame structure, scheduling schemes, and reliability improvement techniques, which have been discussed in the 3GPP Release 15 standardization.

Graphene-based approaches have been influential in the design and manipulation of dental implants and tissue regeneration to overcome the problems associated with traditional titanium-based dental implants, such as their low biological affinity. Here, we describe the current progress of graphene-based platforms, which have contributed to major advances for improving cellular functions in in vitroand in vivoapplications of dental implants. We also present opinions on the principal challenges and future prospects for new graphene-based platforms for the development of advanced graphene dental implants and tissue regeneration.

ABSTRACTThe influence of design parameters related to a ship’s exhaust-gas behavior was investigated using computational fluid dynamics (CFD) for an 8,000 TEU container carrier. To verify the numerical methods, the results were studied by comparing with experimental results. Several test conditions, i.e. various load conditions of ship, wind angle, deckhouse breadth, radar mast height, and exhaust-pipe height and shape were considered for a ship’s exhaust gas flow around the 8,000 TEU container carrier. The influence of the design parameters on contamination by the exhaust gas was quantified, after which the principal parameters to avoid contamination were selected. Finally, the design guideline of yP/H = 2 was suggested to avoid the contamination from the ship’s exhaust gas using the CFD results, model tests, and sea trials.

In this study, the motions of a moored buoy and its surrounding fluid flow are numerically studied. The solver is developed by coupling the computational fluid dynamics platform, OpenFOAM, with a lumped mass mooring line model, MoorDyn. The time marching interface to transfer the solution variables is developed for the robustness and accuracy of the solver. The developed coupled solver was validated against a moored cubic-shaped box model in waves. The different mesh configurations, mesh generation technique and mooring line discretization are considered in the numerical study. A cubic-shaped box attached with tensioned mooring lines in waves is simulated and the results are compared with the experimental results. Motion responses of a moored semi-submersible platform, which is designed by Korea Research Institute of Ship and Ocean Engineering (KRISO), in waves are predicted by the solver. The mooring line tensions acting on the body and anchor, the forces acting on the platform and the platform's motion performance are analyzed, and comparisons are made between simulation data and experimental data.

Supported lipid bilayers (SLBs) are commonly used to investigate interactions between cell membranes and their environment. These model platforms can be formed on electrode surfaces and analyzed using electrochemical methods for bioapplications. Carbon nanotube porins (CNTPs) integrated with SLBs have emerged as promising artificial ion channel platforms. In this study, we present the integration and ion transport characterization of CNTPs in in vivoenvironments. We combine experimental and simulation data obtained from electrochemical analysis to analyze the membrane resistance of the equivalent circuits. Our results show that carrying CNTPs on a gold electrode results in high conductance for monovalent cations (K+and Na+) and low conductance for divalent cations (Ca2+).

We have developed a pyrolysis-based soot-generating system, which is able to control the primary soot particle size. The system is clean and portable and runs on diverse hydrocarbon fuels of interest. To evaluate the performance of the system, soot was generated from n-hexane and propylene with various conditions of the temperature, fuel mole fraction, and residence time in the heating zone. The results showed that the primary soot particle size was controllable within the range of 20–60 nm, and the soot yield as a function of the residence time followed a logistic curve of different shape depending upon the fuel mole fraction and heating temperature. The system that we developed can be used as a reliable soot-generating source for diverse laboratories to meet the growing demands for fundamental research on soot characteristics and soot formation mechanisms as well as the assessment of health and environmental effects of soot from various sources.

Gold nanoparticle (AuNP)−DNA conjugates can enhance in vitrotranslation of a protein. Enhancement occurs viaa combination of nonspecific adsorption of translation-related molecules and the ribosome to the AuNP−DNA and specific binding to the mRNA of interest. AuNP−DNA conjugates enhanced protein production of fluorescent proteins (mCherry, eGFP) in retic lysate mixes by 65−100%. Gel electrophoresis was used to probe nonspecific adsorption of the AuNP−DNA conjugates to the translation machinery. It was determined that nonspecific adsorption is critical for enhancement, and if it was eliminated, expression enhancement did not occur. The interaction of the mRNA with the DNA on the AuNP surface influenced the amount of enhancement and was probed by expression in the presence of RNase H. These results suggest that higher translation enhancement occurs when the DNA on the AuNP forms an incomplete duplex with the mRNA. Tuning the balance between nonspecific adsorption and specific binding of the AuNP−DNA conjugates could result in the translation enhancement of a specific gene in a mixture.

We evaluate Ferguson analysis as a method for simultaneously measuring the size and zeta-potential of gold nanoparticle-DNA (Au NP-DNA) conjugates. This approach is highly suitable when the particle size is <20 nm and biomolecular conformation results in a nonspherical or nonlinear conjugate, causing conventional dynamic light scattering and zeta-potential measurements to be unable to achieve consistent results. We show the applicability of the method by varying the size of gold nanoparticles (5–20 nm) and the loading of methoxypolyethylene glycol/DNA on particle surface and buffer concentrations. Due to the low ionic mobility of tris-borate-EDTA buffer (TBE) and relatively high zeta-potential of Au NP-DNA, Henry’s solutions with higher order correction terms are necessary for obtaining the zeta-potential from the measured free mobility and size.

We report a systematic study of the base-dependent behavior of oligonucleotides linked to Au NP surfaces. Ten 15mer sequences were designed to investigate the effect of oligonucleotide sequence and high-affinity nucleotide location relative to the nanoparticle surface. The nucleotide position was varied within the sequence to be proximal, midway, or distal to the 5′ thiol. High-affinity motifs of adenine, guanine, and cytosine were placed in polythymine sequences, with a homobase oligonucleotide of thymine as a control sequence. Oligonucleotide reactivity toward the NPs and the extent of hybridization of the conjugates varied with sequence. Chemical treatment of the NP surface to remove nonspecific adsorption removed sequence-dependent effects on the hybridization. The behavior of the conjugates can be explained by nonspecific adsorption, where A- and C-containing oligonucleotides have a higher affinity for the NP surface.

Topographic features play a crucial role in the regulation of physiologically relevant cell and tissue functions. Here, an analysis of feature‐size‐dependent cell–nanoarchitecture interactions is reported using an array of scaffolds in the form of uniformly spaced ridge/groove structures for engineering wound healing. The ridge and groove widths of nanopatterns are varied from 300 to 800 nm and the nanotopography features are classified into three size ranges: dense (300–400 nm), intermediate (500–600 nm), and sparse (700–800 nm). On these matrices, fibroblasts demonstrate a biphasic trend of cell body and nucleus elongation showing the maximum at intermediate feature density, whereas maximum migration speed is observed at the dense case with monotonic decrease upon increasing feature size. The directional organization of cell‐synthesized fibronectin fibers can be regulated differently via the nanotopographical features. In an in vitro wound healing model, the covering rate of cell‐free regions is maximized on the dense nanotopography and decreased with increasing feature size, showing direct correlation with the trend of migration speed. It is demonstrated that the properties of repaired tissue matrices in the process of wound healing may be controlled via the feature‐size‐dependent cell–nanoarchitecture interactions, which can be an important consideration for designing tissue engineering scaffolds. Nanotopographic featuresplay a crucial role in the regulation of physiologically relevant cell and tissue functions. Here, the feature‐size‐dependent cell–nanoarchitecture interactions are systemically analyzed using an array of directional matrix nanotopography. It is shown that the properties of repaired tissue matrices in the process of dermis wound healing may be controlled via nanotopographical density‐mediated cellular behaviors.