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Transformative bioprinting, particularly 4D printing, is revolutionizing the field of biofabrication, offering dynamic solutions that respond to external stimuli. This paper explores the underlying mechanisms, materials, and stimuli that enable 4D printing to fabricate responsive and adaptive constructs. Section 1 delves into the foundational aspects of 4D bioprinting, detailing the stimuli-responsive materials, such as hydrogels and shape-memory polymers, and the mechanisms that drive their transformation. Additionally, the role of external factors, including temperature, pH, and magnetic or light-based stimuli, is analyzed to provide a comprehensive understanding of this evolving technology. Section 2 focuses on the diverse applications of 4D bioprinting, particularly in biomedical sciences. Key use cases include tissue engineering, drug delivery systems, and the creation of adaptive implants. Beyond healthcare, the potential for smart structures in fields like robotics and aerospace is highlighted, showcasing the technology's ability to deliver tailored, dynamic solutions across various domains. Section 3 categorizes additive manufacturing techniques relevant to 4D printing, offering an in-depth classification and comparison. This includes extrusion-based, vat polymerization, and inkjet printing technologies, emphasizing their compatibility with stimuli-responsive materials. Section 4 shifts focus to commercial advancements, presenting a classification of 4D bioprinters available in the market. The economic barriers, challenges in scalability, and ease of application for these printers are critically examined. Proposed solutions, such as innovative material sourcing, streamlined design strategies, and integration with AI for optimized performance, are presented to address these issues. This work provides a roadmap for integrating 4D bioprinting into scalable and cost-effective production, pushing the boundaries of biofabrication. It serves as a comprehensive guide for researchers and industries aiming to harness the transformative potential of 4D printing for adaptive and functional applications across various domains.

Surface segregation of components is a key factor in determining the physicochemical properties and catalytic activity of bimetallic nanoparticles. In this study, computer simulations are used to analyze the metal distribution of Ir-Pd nanoparticles synthesized via microemulsions. Based on the high difference between the reduction potentials, an Ir-core/Pd-shell structure is expected. However, experimental results have shown a higher Ir fraction at the surface (15-23%). The hypothesis is that this unexpected results may be due to differences in nucleation rates. To investigate this, we performed a systematic study on the influence of critical nucleus size on the final nanostructure when the two metals have very different reduction rates. Our aim was to determine the conditions under which Ir can reach the nanoparticle surface. The results confirm that the large difference in reduction rates mainly governs metal segregation, leading to core-shell structures. However, when the concentration is close to the critical nucleus value, a slower nucleation rate results in higher Ir enrichment at the surface. It can be attributed to both a slow homoatomic nucleation rate and to a slow heteroatomic nucleation rate of Ir-Pd. At higher concentrations, this effect disappears as the higher reactant availability facilitates nucleation, resulting in similar metal segregation regardless of the critical nucleus size. Good agreement between experimental and simulation results supports the conclusions of this study.

Wide-bandgap semiconductor materials, exemplified by silicon carbide (SiC), have emerged as pivotal materials in semiconductor devices due to their exceptional chemical stability, high electron mobility, and thermal stability. With the rapid development of microelectronic devices and integrated optical circuits, the demand for high-yield and high-quality processing of SiC wafer has intensified. Traditional SiC wafer processing technologies suffer from low efficiency and high material loss, making it difficult to meet industrial demands. Therefore, the development of efficient, low-damage processing techniques has become a pressing issue in the SiC wafer processing field. Ultrashort pulsed laser processing, with its advantages of contact free processing, no mechanical stress, and small heat-affected zones, has garnered significant attention in SiC wafer processing in recent years. By generating a modified layer within the material, laser processing plays a crucial role in wafer fabrication. However, the key challenge lies in precisely controlling the thickness of the modified layer down to the micro-nano scale to minimize material loss. This review systematically discusses the interaction mechanisms and modification processes of laser with wide-bandgap semiconductor SiC materials. It focuses on the core issue in laser modification technology, where nonlinear effects make it difficult to precisely control the modification layer depth, thereby affecting both modification quality and processing efficiency. To address this, the paper summarizes the differences in modification mechanisms with lasers of varying pulse durations and proposes a multi-strategy solution to improve modification quality and processing efficiency through pulse control and synergistic optimization of process parameters. Additionally, this review provides a comprehensive overview of advanced SiC wafer detachment processes, including cold cracking stripping, chemically assisted stripping, ultrasonic stripping, and multi-laser composite stripping, and identifies the primary challenges and future directions in the field of SiC wafer processing.

Dental biofilms are complex microbial communities enclosed by a self-produced extracellular matrix, leading to dental caries, periodontitis, and other oral diseases. These biofilms are often resistant to conventional antibiotics and result in persistent infections that negatively impact oral health. Recent advances in nanotechnology have demonstrated nanoparticles as a promising therapeutic alternative for controlling dental biofilms. In addition, such nanoparticles possess unique physicochemical properties such as high surface area-to-volume ratio, enhanced reactivity, and ability to penetrate biofilm structures. Therefore, this review explores the potential of various nanoparticles, such as silver, zinc oxide, and titanium dioxide, in disrupting biofilm formation and removal of pathogenic oral biofilm forming bacteria. Additionally, this review critically examines various strategies for surface functionalization of nanoparticles to enhance their antimicrobial efficacy and biofilm-targeting capabilities. Furthermore, the article also presents various applications of dental materials coated with nanoparticles in preventing biofilm adhesion and growth. In essence, this review article will provide collective information on various approaches in using nanoparticles to reduce the risk of recurrent oral infections and enhance overall dental health.

The swift and far-reaching evolution of advanced nanostructures and nanotechnologies has accelerated the research rate and extent, which has a huge prospect for the benefit of the practical demands of solid-state hydrogen storage implementation. Carbonaceous materials are of paramount importance capable of forming versatile structures and morphology. This review aims to highlight the influence of the carbon material structure, dimension, and morphology on the hydrogen storage ability. An extensive range of synthesis routes and methods produces diverse micro/nanostructured materials with superb hydrogen-storing properties. The structures of carbon materials used for hydrogen adsorption, from 0 to 3D, and fabrication methods and techniques are discussed. Besides highlighting the striking merits of nanostructured materials for hydrogen storage, remaining challenges and new research avenues are also considered.

The synthesis of nanomaterials has recently shifted toward environmentally benign approaches that mitigate the drawbacks of conventional chemical methods. In this context, plant-mediated green synthesis offers a sustainable and versatile alternative for producing nanoparticles with unique physicochemical properties and diverse applications. This study presents the green synthesis of hematite iron oxide nanoparticles (α-Fe₂O₃ NPs) using aqueous leaf extracts of Sorghum bicolor. The resulting nanoparticles were characterized using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). XRD analysis confirmed the formation of a crystalline rhombohedral hematite phase with an average crystallite size of 46.8 nm. SEM and TEM images revealed predominantly spherical particles with evident agglomeration, while EDX analysis confirmed iron (Fe) and oxygen (O) as the primary elemental constituents. Antioxidant activity assessed via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay showed a concentration-dependent radical scavenging effect, with higher α-Fe₂O₃ NP concentrations required to achieve 50% inhibition. Cytotoxicity studies on HeLa (cancer) and HEK293 (normal) cell lines indicated selective toxicity, with the nanoparticles preferentially affecting cancer cells while sparing healthy ones. Although the α-Fe₂O₃ NPs exhibited lower potency compared to the standard chemotherapeutic agent 5-fluorouracil, their concentration-dependent reduction in cell viability supports the hypothesis that cancer cells are particularly vulnerable to disruptions in iron homeostasis. This cost-effective and eco-friendly synthesis method underscores the potential of Sorghum bicolor-mediated α-Fe₂O₃ nanoparticles for future biomedical applications.

The urgent need for bi-functional high-performance non-noble metal-based catalysts for water splitting requires the integration of both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) together, which not only increases the energy efficiency but also reduces fabrication cost. However, most non-noble metal-based catalysts for OER are not stable under alkaline conditions, while HER shows poor kinetic performance under alkaline conditions, which prevents the water splitting from scale-up applications. Therefore, in this paper, non-noble metal-based catalyst of Ni₃S₂@MoO₃@Co₃O₄@AMO/NF was prepared by a two-step hydrothermal method followed by a galvanic replacement reaction with morphological characterization, demonstrating that the synthesized material has a core-shell structure. The electrochemical properties of Ni₃S₂@MoO₃@Co₃O₄@AMO/NF were tested and analyzed, which confirmed its efficient electrocatalytic activity. The catalyst exhibited excellent OER in 1 M KOH solution, and a low overpotential of 248 mV was achieved at a current density of 10 mA cm^-2. In addition, the catalyst maintained competitively low overpotentials even at high current densities, 281 mV and 303 mV at 50 mA cm^-2 and 100 mA cm^-2, respectively. Remarkably, only an overpotential of 185 mV was required to reach the current density of 10 mA cm^-2 for HER. The excellent OER and HER performances could be attributed to the synergistic effects among AMO, Co₃O₄ and MoO₃. In addition, Ni₃S₂@MoO₃@Co₃O₄@AMO/NF required only 1.414 V at 10 mA cm^-2 to complete the overall water splitting and exhibited excellent competitiveness also at high current densities (1.769 V and 1.975 V at 50 mA cm^-2 and 100 mA cm^-2, respectively). The morphology of Ni₃S₂@MoO₃@Co₃O₄@AMO remained stable after long time i-t tests, which proved its long-term operational stability. The Faraday efficiencies of the OER and HER could reach 75.92% and 97.51%, respectively, which showed excellent electrocatalytic performance. Therefore, the synthesis of high-performance bifunctional catalysts based on a two-step hydrothermal reaction followed by a galvanic replacement reaction proposed in this study provides a new strategy for the simple and efficient synthesis of non-noble metal-based catalysts for high-performance overall water splitting.

Triple-negative breast cancer (TNBC) is a prevalent and aggressive subtype of breast cancer, accounting for approximately 10-15% of all cases. Its lack of hormone receptors and poor clinical prognosis make targeted therapy particularly challenging, leaving chemotherapy as the mainstay treatment. However, conventional chemotherapy is associated with significant limitations, including cardiotoxicity and inadequate tumor cell specificity. Nanoparticle-based drug delivery systems have emerged as a promising strategy for enhancing the therapeutic efficacy of doxorubicin (DOX) in TNBC. Among these, cell membrane-coated nanoparticles, exosome-sheathed porous silica nanoparticles, and FZD7-targeted nanoparticles have demonstrated substantial potential. These platforms improve drug delivery efficiency while minimizing systemic toxicity and adverse effects. Cell membrane-coated nanoparticles evade immune surveillance, allowing for selective targeting of TNBC cells. Exosome-sheathed nanoparticles facilitate the co-delivery of DOX with other therapeutic agents aimed at inhibiting cancer stem cell-driven epithelial-to-mesenchymal transition. FZD7-targeted nanoparticles enhance DOX accumulation within tumor cells by binding specifically to FZD7 receptors, leading to increased apoptosis and reduced cancer cell metabolic activity. This review aims to examine recent advancements in nanoparticle-based delivery systems for DOX in the treatment of TNBC. It further explores various formulations-including liposomes and polymeric nanoparticles-used for DOX delivery, assesses active and passive targeting strategies, and evaluates the advantages of controlled drug release. The review also identifies current gaps in the literature and proposes future research directions to advance the clinical applicability of these systems. Emerging concepts such as the active transport and retention mechanism and macrophage-mediated delivery systems offer new opportunities to improve tumor localization and retention of DOX-loaded nanoparticles. Collectively, these developments underscore the transformative potential of nanoparticle-based DOX delivery in revolutionizing TNBC therapy.

Borophene and silicene, two novel members of the Xene family, feature high surface reactivity and stability suitable for sensing applications. However, the gas sensing capabilities of these materials in their pristine form have not been systematically investigated. Here we show that borophene- and silicene-based quartz crystal microbalance (QCM) sensors achieve stable and sensitive relative humidity detection and we model their adsorption-desorption mechanisms. Borophene and silicene nanosheets were synthesized via liquid-phase exfoliation and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller surface area analysis. The QCM sensors exhibited sensitivities of 3.2 Hz/%RH and 3.9 Hz/%RH, response/recovery times of 122/65 s and 47/130 s and hysteresis of 1.8% and 3.8% hysteresis for borophene and silicene, respectively. The dominant sensing mechanism was determined to be chemisorption, supported by thermodynamic modeling. These results suggest that 2D borophene and silicene can significantly contribute to sensing applications, especially in environments requiring air stability.

To be used as efficient alpha particle scintillator in the fields of nuclear security, nuclear nonproliferation and high-energy physics, scintillator screens must have high light output and fast decay properties. While there has been a great deal of progress in scintillation efficiency, achieving fast decay time properties are still a challenge. In this work, the near band edge (NBE) UV luminescence and alpha particle induced scintillation properties of vertically aligned densely packed ZnO nanorods (NRs) doped with Al, Ga, and In have been thoroughly investigated. The high crystalline hexagonal wurtzite structure with a strong orientation through the c-axis plane (002) and aspect ratios in the range 13-22 have been observed for all ZnO NRs. Electron paramagnetic resonance (EPR) analysis exhibited paramagnetic signals at g ≈ 1.96 for all ZnO NRs. A cost effective green hydrothermal synthesis technique was employed to grow well-aligned NRs. Using citrate as an additive acting as a strong reducing agent in the solution during the crystal growth, defects on the surface are significantly suppressed, thereby enhancing the NBE UV emission. Significantly higher NBE UV emission was observed from the top surface of ZnO NRs in cathodoluminescence (CL) microscopy. Results show that citrate assisted donor doping of ZnO NRs not only reduces the defect emission and NBE self-absorption, but also induces fast decay time (~ 600-700 ps), which makes ZnO NRs a good candidate for fast alpha particle scintillator screens used in associated particle imaging for time and direction tagging of individual neutrons generated in D-T and D-D neutron generators.