Fabrication Method Research Articles

Chain-based lattice printing for efficient robotically-assembled structures

Due to the nature of their implementation, nearly all low-level fabrication processes produce solidly filled structures. However, lattice structures are significantly stronger for the same amount of material, resulting in structures that are much lighter and more materially efficient. Here we propose an approach for fabricating lattice structures that echoes 3D printing techniques. In it, a modular chain of specially designed links is “extruded” onto a substrate to produce various lattices configurations depending on the chosen assembly algorithm, ranging from rigid regular lattices with nodal connectivity of 12, octet-truss, to significantly less dense configurations. Compared to conventional additive manufacturing methods, our approach allows for efficient use of nearly any material or combination of materials to construct lattices with programmed arrangements. We experimentally demonstrate that a 3x3x2 lattice structure (287 total links) is fabricated in 27 minutes via a modified robotic arm and can support approximately 1000 N in compression testing.

Advances and Challenges of Microneedle Assisted Drug Delivery for Biomedicals Applications: A Review.

Microneedles have been explored as a novel way of delivering active ingredients into the skin. They have various advantages, such as quick and efficient drug delivery, mechanical stability, minimal pain, variable capacity and easy use. Microneedles are enabled for the delivery of vaccine, peptides, medicinal components and in cosmetology, which couldn't go unnoticed. The novel approaches in the transdermal drug delivery system have increased the efficiency of drug delivery into the skin by crossing the skin barriers. This platform has a wide range of applications and can also be used to deliver non-transdermal biomedicals. The variety in the design of microneedles has demanded similar diversity in their methods of fabrication; micro molding and drawing lithography may be useful methods. There are different types of polymers and materials for the fabrication of microneedles. Several synthetic and natural materials are used in the fabrication of microneedles. Unique shapes, materials, and mechanical properties are modified for organ-specific applications in microneedle engineering. In this review, we discuss several factors and their roles to cross the biological barriers for transdermal drug delivery in various sites, such as in ocular, vascular, oral, and mucosal tissue. Additionally, this article highlights the future scope of transdermal drug delivery systems through microneedles.

Investigation of formation, microstructure and hardness of Ti-6Al-4V single tracks via Joule-fused filament additive manufacturing

Purpose This paper aims to investigate a novel additive manufacturing (AM) method for titanium alloy using Joule heat as the single heat source to melt TC4 wire, which intends to provide a new low-power, low-cost solution for the processing of titanium alloys. Design/methodology/approach When current flows through the wire and the substrate, Joule heat will be generated to melt the wire and join the wire with the substrate. By stacking the wire layer by layer, finally a part can be formed. The cross-sectional morphology, microstructure and hardness of TC4 single track deposits formed by Joule heat melting wire AM were investigated by various characterization methods. Findings The melting width and melting penetration decreased with the increase of printing speeds. There is no obvious change in single track morphology with the change of printing pressures. The melting width and melting penetration increased with the increase of printing currents. The observation of the internal microstructure of a single track reveals a decrease in grain size as printing speeds increase. The average hardness of the single track was about 363 HV, which is comparable to the hardness of the parts fabricated by selective laser melting process. The printing power is less than 300 W, which is lower than other AM processes. Originality/value This paper provides a novel solution for the processing of titanium alloy parts. Compared with other expensive energy sources, this work only uses an ordinary DC power supply as the energy source. The printing process is simple and the cost is low. The power is much lower than other AM processes.

A Universal Approach for High-Yield Synthesis of Single-Crystalline Ordered Macro-Microporous Metal-Organic Frameworks.

Despite the excellent properties of single-crystalline ordered macro-microporous MOFs (SOM-MOFs) compared to conventional MOFs, their further development has been hindered by the lack of versatile and high-yielding preparation protocols. This study introduces an innovative universal fabrication method that can easily solve the two major challenges of precursor stabilization and crystallization modulation, enabling the efficient synthesis of various SOM-MOFs with high yields. Notably, our approach has successfully yielded SOM-MIL-88A, a novel MOF showcasing exceptional stability in both water and acidic solutions, a remarkable achievement unprecedented in prior SOM-MOF research. SOM-MIL-88A has demonstrated exponentially improved performance over conventional MIL-88A in adsorption, catalysis, immobilized enzymes, and composite biosensing. Furthermore, our versatile protocol has been successfully applied to synthesize SOM-HKUST-1 and SOM-ZIF-8, resulting in significantly improved yields (increase by about 10-fold and 2-fold, respectively, compared to the previously reported protocol). This groundbreaking achievement marks a pivotal advancement in the preparation of diverse SOM-MOFs with tailored properties, presenting exciting prospects for future research on MOFs.

Vertical silicon nanowedge formation by repetitive dry and wet anisotropic etching combined with 3D self-aligned sidewall nanopatterning

Three-dimensional (3D) stacking of nano-devices is an effective method for increasing areal density, especially as downscaling of lateral device dimensions becomes impractical. This stacking is mainly achieved through plasma processing of stacked layers on top of a silicon (Si) substrate, which offers process flexibility but poses challenges in obtaining vertical sidewalls without plasma induced damage. A novel wafer-scale fabrication method is presented for realizing sub-200 nm vertically stacked Si nanowedges at the wafer scale, using iterative dry etching, wet anisotropic etching, and thermal oxidation. This approach forms nanowedges by the slow etching {111} Si planes, resulting in smooth surfaces at well-defined angles. A silicon nitride (Si3N4) hard mask is used in an iterative (etch-and-deposit) process, with its thickness determining the number of process iterations. By optimizing etch selectivity during dry etching and/or increasing the initial Si3N4 thickness, the number of process iterations can be increased. The periodicity of the nanowedges can be adjusted by varying the etch time of both dry and wet anisotropic etching. A thin silicon dioxide (SiO2) layer (∼6 nm) is grown on the nanowedges during each iteration. 3D sidewall patterning at the sub-20 nm scale is achieved using corner lithography and local oxidation of Si to selectively open the concave corners. Rhombus-shaped structures are formed at each concave corner after wet anisotropic etching of Si. This novel technology platform will allow for the 3D fabrication of high-density nanodevices for electronic, fluidic, plasmonic, and other applications.

Accuracy of 3-dimensional surgical guide for endodontic microsurgery with a new design concept: A cadaver study.

Despite the high success rate of endodontic microsurgery (EMS), it is difficult to suggest EMS as a general treatment option considering the difficulty of the procedure. A surgical guide has been proposed to overcome this problem. This study aimed to evaluate the stability of the surgical guide of a new design concept, as well as the accuracy of root resection, and to introduce the manufacturing method of the newly designed surgical guide. The experiment was conducted on 59 roots (9 in the maxillary and 50 in the mandibular region) of adult human cadavers. The surgical guide was designed using CAD/CAM design software based on cone-beam computed tomography (CBCT) images and optical scan files. Unlike conventional surgical guides, the surgical guide proposed herein was designed to act as a tooth-bone-supported removable appliance. Two different types of guides were prepared: the osteotomy guide (O guide) for separation of the cortical bone above the root tip with a trephine bur with an outer diameter of 6 mm and the root resection guide (R guide) for resection of the root tip with a trephine bur with an outer diameter of 4 mm. For stability evaluation, the guides were pressed at five predetermined locations after installation and checked for the presence of any movement. For accuracy evaluation, the length at which the root tip was cut was measured and examined by overlapping the preoperative and postoperative CBCT images. Of the 15 R guides, 14 were stably installed without mobility. For the R guide group, the root tip was resected with an average of 3.2 mm, showing better results than the no-guide group with an average of 4.0 mm. The newly designed surgical guide of this study can be applied more stably, enabling root resection to be performed more accurately and simply according to the preoperative plan than when performed without a guide.

A Review on Advances and Challenges in Core-Shell Scaffolds for Bone Tissue Engineering: Design, Fabrication, and Clinical Translation.

This review explores core-shell scaffolds in bone tissue engineering, highlighting their osteoconductive and osteoinductive properties critical for bone growth and regeneration. Key design factors include material selection, porosity, mechanical strength, biodegradation kinetics, and bioactivity. Electrospun core-shell nanofibrous scaffolds demonstrate potential in delivering therapeutic agents and enhancing bone regeneration. Critical characterization techniques include structural, surface, chemical composition, mechanical, and degradation analyses. Scaling up production poses challenges, addressed by innovative electrospinning techniques. Future research focuses on regulatory and commercial considerations, while exploring advanced materials and fabrication methods to optimize scaffold performance for improved clinical outcomes.

Scalable Fabrication of Neuromorphic Devices Using Inkjet Printing for the Deposition of Organic Mixed Ionic‐Electronic Conductor

AbstractRecent advancements in artificial intelligence (AI) have highlighted the critical need for energy‐efficient hardware solutions, especially in edge‐computing applications. However, traditional AI approaches are plagued by significant power consumption. In response, researchers have turned to biomimetic strategies, drawing inspiration from the ion‐mediated operating principle of biological synapses, to develop organic neuromorphic devices as promising alternatives. Organic mixed ionic‐electronic conductor (OMIEC) materials have emerged as particularly noteworthy in this field, due to their potential for enhancing neuromorphic computing capabilities. Together with device performance, it is crucial to select devices that allow fabrication via scalable techniques. This study investigates the fabrication of OMIEC‐based neuromorphic devices using inkjet printing, providing a scalable and material‐efficient approach. Employing a commercially available polymer mixed ionic‐electronic conductor (BTEM‐PPV) and a lithium salt, inkjet‐printed devices exhibit performance comparable to those fabricated via traditional spin‐coating methods. These two‐terminal neuromorphic devices demonstrate functionality analogous to literature‐known devices and demonstrate promising frequency‐dependent short‐term plasticity. Furthermore, comparative studies with previous light‐emitting electrochemical cells (LECs) and neuromorphic OMIEC devices validate the efficacy of inkjet printing as a potential fabrication technique. The findings suggest that inkjet printing is suitable for large‐scale production, offering reproducible and stable fabrication processes. By adopting the OMIEC material system, inkjet printing holds the potential for further enhancing device performance and functionality. Overall, this study underscores the viability of inkjet printing as a scalable fabrication method for OMIEC‐based neuromorphic devices, paving the way for advancements in AI hardware.

Synthesis and Characterization of Carbonaceous Materials for Medical Applications: A Comprehensive Review

Carbonaceous materials have gained significant attention in recent years for their various applications in the field of medicine and biotechnology. This comprehensive review explores the synthesis and characterization of carbon-based materials and their potentials in various medical applications. The paper delves into the methods of fabrication of carbon-based nanoparticles, such as carbon nanotubes, biochar, and graphene, while highlighting their unique properties. Characterization techniques, such as microscopy, spectroscopy, and surface analysis, are discussed to provide insights into the chemical and structural properties of these materials. Furthermore, the review examined their wide-ranging medical applications, encompassing tissue engineering, drug delivery, biosensing, and imaging, showcasing the versatility and promising contributions of carbonaceous materials in the healthcare industry. The review outlines the current challenges and prospects in the field, emphasizing the growing significance of carbon-based materials as valuable tools in advancing medical science and technology, as well as public health.

Manufacturing the current flow diverter architecture in REBCO tapes using silver inkjet printing

Abstract A low normal zone propagation velocity (NZPV) combined with critical current inhomogeneities favor the nucleation of destructive hot spots in rare-earth barium copper oxide (REBCO) tapes. Increasing the NZPV using the current flow diverter (CFD) concept is a promising solution to mitigate the risk of developing hot spots. The fabrication method of CFD REBCO tapes implies several steps consisting in masking, silver etching, mask removal, and silver deposition, which takes time and remains a barrier to the implementation of a low-cost industrial production of long-length CFD REBCO tapes. This work presents a cost-effective and maskless CFD fabrication approach that relies on inkjet printing (IJP) of silver patterns directly on top of the REBCO layer to create a non-uniform interfacial resistance between the silver and the REBCO surface, along the width of the tape. The parameters of IJP and oxygen annealing were optimized to obtain highly conductive silver patterns deposited on the surface of the REBCO layer. CFD REBCO tapes were successfully fabricated using commercial REBCO tapes and the proposed method without degrading the superconducting properties. Experimental measurements revealed an increase of the NZPV by a factor of 6-7 compared to commercial REBCO tapes.

Electrohydrodynamic effect within CFRP laminates by bipolar nsPDC electric field during the curing process

In this paper, a new method based on bipolar nanosecond pulsed superimposed direct current (nsPDC) electric field assisted curing technique was developed to fabricate modified fiber-reinforced composites to enhance their mechanical properties. It was found that the mode I interlaminar fracture toughness of the electric field-modified CFRP laminates reached 1014.2 MPa, which increased by 80.4 %. The average tensile strength and tensile modulus were 2180 MPa and 100780 MPa, respectively, which were 20.7 % and 3.5 % higher than the blank control group. The enhancement mechanism was explored by COMSOL simulation, curing temperature inspection, and microscopic characterization by electron microscopy. The results show that the presence of electric field and electric field force inside the laminate, which affects the flow of resin and the weak migration of fibers, enables the elimination of larger air bubbles present in the material, the reduction of resin-rich zones in the interlayer as well as the improvement of the fiber-resin wettability without significantly altering the curing temperature. The proposed simple, convenient, and environmentally friendly strategy can effectively regulate some of the deficiencies in the conventional manufacturing methods and thus is suitable for the optimal design of fiber-reinforced composites.

Fractal Modelling of Heterogeneous Catalytic Materials and Processes

This review considers the use of fractal concepts to improve the development, fabrication, and characterisation of catalytic materials and supports. First, the theory of fractals is discussed, as well as how it can be used to better describe often highly complex catalytic materials and enhance structural characterisation via a variety of different methods, including gas sorption, mercury porosimetry, NMR, and several imaging modalities. The review then surveys various synthesis and fabrication methods that can be used to create catalytic materials that are fractals or possess fractal character. It then goes on to consider how the fractal properties of catalysts affect their performance, especially their overall activity, selectivity for desired products, and resistance to deactivation. Finally, this review describes how the optimum fractal catalyst material for a given reaction system can be designed on a computer.

Correction: Electronic textiles (E-Textiles): types, fabrication methods, and recent strategies to overcome durability challenges (washability & flexibility)

Correction: Electronic textiles (E-Textiles): types, fabrication methods, and recent strategies to overcome durability challenges (washability & flexibility)

Polymersomes as Next Generation Nanocarriers for Drug Delivery: Recent Advances, Patents, Synthesis and Characterization

Background: Polymersomes (PS), self-assembled nanostructures formed by amphiphilic block copolymers, have garnered significant attention in recent years due to their unique properties and versatile applications in the fields of drug delivery and biomedicine. They are being prepared for a wide range of complex medicinal compounds, including nucleic acids, proteins, and enzymes. Polymersomes have lately been used as vehicles for delivering varied therapeutic substances and regulating ROS (reactive oxygen species). Due to their immunogenic features, polymersomes could play a critical role in enhancing subunit vaccine and drug delivery against COVID-19 infection. Objective: The prime purpose of this manuscript is to furnish an extensive overview of polymersomes, highlighting their recent advances, fabrication methods, characterization techniques, and pharmaceutical applications. Methods: The article has been amassed using several online and offline manuscripts from reputed journals, books, and other resources. Besides this, various user-friendly interfaces, like Pubmed, Google Scholar, etc, have been utilized to gather the latest data about polymersomes. This domain encompasses recent advancements in the realm of innovations about the delivery of drugs through polymeric vesicles. This field involves innovations or developments in nanocarrier systems as they are efficaciously employed to deliver the desired moiety to the targeted site. Results: PS have been discovered to exhibit remarkable promise in addressing various challenges associated with inadequate bioavailability, targeted drug delivery, dosing frequency, and diminished toxic effects. Over the past decade, such nanovesicles have been effectively employed as a complementary approach to address the issues arising from poorly soluble medications. However, this domain still requires further focus on novel breakthroughs. Conclusion: Polymersomes demonstrate unparalleled potential as innovative carriers, exhibiting remarkable versatility and exceptional biocompatibility. This concise review underscores their extraordinary prospects in diverse fields, accentuating their distinctive attributes and opening new avenues for groundbreaking applications.

Liposomal Nω-hydroxy-l-norarginine, a proof-of-concept: arginase inhibitors can be incorporated in liposomes while retaining their therapeutic activity ex vivo

Cancer immunotherapy has evolved significantly over the last decade, with therapeutics targeting the adaptive immune system showing exciting effects in clinics. Yet, the modulation of the innate immune system, particularly the tumor-associated innate immune cells which are an integral part of immune responses in cancer, remains less understood. The arginase 1 (Arg1) pathway is a pivotal metabolic pathway that tumor-associated innate immune cells exploit to create an immunosuppressive tumor microenvironment, leading to the evasion of immune surveillance. The inhibition of Arg1 presents a therapeutic opportunity to reverse this immunosuppression, and Nω-hydroxy-l-norarginine (nor-NOHA) has emerged as a potent arginase inhibitor with promising in vivo efficacy. However, the rapid systemic clearance of nor-NOHA poses a significant challenge for its therapeutic application. This study pioneers the encapsulation of nor-NOHA in liposomes, aiming to enhance its bioavailability and prolong its inhibitory activity against Arg1. Historically, the extensive interaction between innate immune cells and nanoparticles has been one of the biggest drawbacks in nanomedicine. Here we seek to utilize this effect and deliver liposomal nor-NOHA to the arginase 1 expressing innate immune cells. We systematically investigated the effect of lipid composition, acyl chain length, manufacturing and loading methodology on the encapsulation efficiency (EE%) and release profile of nor-NOHA. Our results indicate that while the manufacturing method and lipid acyl chain length do not significantly impact EE%, they crucially influence the release kinetics of nor-NOHA, with longer acyl chains demonstrating a more sustained release of nor-NOHA from liposomes enabling continuous inhibition of Arg1. Our findings suggest that liposomal nor-NOHA retains its functional inhibitory activity and could offer improved pharmacokinetic properties, making it a compelling base for iterations for further innovative cancer immunotherapeutic strategies in preclinical and clinical evaluations.

An integrated hot embossing and thermal reflow method for precision manufacture of plano-convex glass microlens arrays

An integrated hot embossing and thermal reflow method for precision manufacture of plano-convex glass microlens arrays

Customized flexible iontronic pressure sensors: Multilevel microstructures by 3D-Printing for enhanced sensitivity and broad pressure range

Flexible capacitive pressure sensors stand out for their energy efficiency, rapid responsiveness, and exceptional durability, with their performance hinging on the intricate design of microstructures and the strategic selection of dielectric materials. However, creating cost-effective and practical fabrication methods for these components continues to pose a significant challenge. This study unveils an innovative iontronic flexible pressure sensor that integrates an ionic layer with sophisticated multilayer microstructures, setting new benchmarks in pressure sensing technology. The sensor operates within an expansive pressure range, achieving sensitivities as high as 92.14 kPa−1 at pressures from 0 to 50 kPa, and 22.96 kPa−1 at pressures ranging from 50 to 800 kPa, demonstrating extraordinary sensitivity. It also achieves an exceptionally low detection limit of 6.67 Pa and features swift response times of 56 ms to activate and 18 ms to deactivate. Enhanced by the addition of CuSO4, the sensor not only withstands freezing conditions but also significantly boosts sensitivity. Moreover, this sensor is capable of detecting human joint movements and subtle pressure fluctuations under high-pressure conditions, suggesting a breakthrough in the field. This research presents a simple, reliable, and cost-efficient method for developing flexible iontronic pressure sensors, poised to revolutionize applications in wide-ranging pressures and adverse temperature environments.

Impact of Hydrochloric Acid Doping on Polyaniline Conductivity and Piezoelectric Performance in Polyaniline/Bismuth Oxyiodide Nanocomposites

This study investigates the impact of hydrochloric acid (HCl) doping, ranging from 0.2 M to 1.25 M, on the conductivity of polyaniline (PANI) and the piezoelectric performance of polyaniline/bismuth oxyiodide (PANI/BiOI) nanocomposites (NCs). Two distinct methods for fabricating NCs based on PANI and bismuth oxyiodide (BiOI) are proposed. Two distinct methods for fabricating PANI/BiOI NCs are proposed, and their optical and electrical properties are systematically examined. The direct allowed energy bandgap of the NCs is found to be approximately 1.9 eV. The piezoelectric performance, attributed to the 2D Janus structure of BiOI, is explored in detail, with the bulk piezoelectric coefficient measured at 1.43(65) pm/V. Sensitivity to pressure interaction reached 21.1(92) mV/bar, and the generated power was 5.09 nW for air pressure excitation in a composite consisting of 37.5 wt% BiOI and 62.5 wt% PANI doped with 0.2 M HCl, fabricated in-situ. The results demonstrate precise control over key parameters, including the fabrication method, sample thickness, HCl doping concentration, and BiOI content, highlighting the significant potential for enhancing nanogenerator functionality. These findings provide valuable insights into improving the performance of piezoelectric materials for energy harvesting technologies.

Skutterudites as sustainable thermoelectric material- A critical review

In this article, we comprehensively reviewed the thermoelectric proper- ties of skutterudites-based materials. We discussed the various synthesis methods like non-chemical and chemical methods for the synthesis of the skutterudites materials for thermoelectric applications. In particular, this review articles also consolidates the information on how the filler plays a crucial role in improving the thermoelectric performance of the skutterudites materials. In addition, this review also concentrates on diverse fabrication methods employed in the production of skutterudites to optimize their thermoelectric performance. It also elucidates the efficiency of devices based on skutterudite materials and discusses the applications of thermoelectric devices.

Development of a 3D Printed Chemiluminescence Smartphone Detector for High Performance Liquid Chromatography

A novel chemiluminescence detector for high-performance liquid chromatography (HPLC) was designed that incorporates a smartphone as photodetector, signal processor, and data storage unit. All detector components, including flow cell, flow cell holder, mixers, and housing, were fabricated by 3D printing and integration of the smartphone and 3D printed components provides a portable, low-cost, and user-friendly device. The detector was applied in the determination of carbamazepine using HPLC through a chemiluminescence reaction with tris(2,2′-bipyridyl)ruthenium(II) and cerium sulfate. Design and fabrication of the flow cell using two fabrication methods—3D printing and laser cutting—along with the integration of a mixer and the optimization of smartphone parameters were investigated. To expand the applicability of the detector for other analytes and different chemiluminescence reactions, detection of three piperazine derivatives by reaction with tris(2,2′-bipyridyl)ruthenium(II) and four phenethylamine compounds via reaction with acidic potassium permanganate reagent was studied. The linear dynamic range, limit of detection, and limit of quantification of the detector for the determination of carbamazepine were measured as 3.0–30.0 mg/L, 1.0 mg/L, and 3.0 mg/L, respectively, using the Samsung S20 smartphone device. Intraday and interday precision was evaluated for carbamazepine, with relative standard deviation (RSD) values for intraday precision ranging from 1.7% to 6.2% (n = 3) and interday precision RSD values ranging from 3.2% to 4.8% (n = 9).