Innovative 3D Printing Research Articles

3D-printed Bio-inspired porous electrode by bidirectional enhancement strategy with high mass loading and enhanced energy density for supercapacitors

The effective strategy for increasing areal capacity involves the use of 3D printed thick-electrode with high mass loading. However, thick-electrode still encounters challenges such as incomplete electrolyte penetration and slow ion transport. Here, we successfully prepared lignocellulosic nanofibrils (LCNFs) from abundant bamboo biomass and developed functional ink composed of LCNFs/ carbon nanotubes (CNTs) / polyaniline (PANI) / polyvinyl alcohol (PVA) for printing. An innovative 3D printing bidirectional enhancement strategy was proposed to increase the mass loading of active materials in the vertical direction and construct ion transport channels in the transverse direction. The biomimetic porous N-doped electrode obtained after annealing treatment exhibits a more continuous conductive network, larger surface area, higher utilization of active materials, and smoother ion transport pathways compared to thick-electrode. Therefore, the Triangles biomimetic electrode exhibits an enhanced areal/specific capacitance compared to thick-electrode, reaching 5.30 F·cm−2 (184.03 F·g−1) and 4.40 F·cm−2 (122.22 F·g−1) at 2 mA·cm−2, respectively. The symmetric device demonstrates an areal capacitance of 1.34 F·cm−2 at 1 mA·cm−2 and achieves an energy density of 0.186 mWh·cm−2 at a power density of 0.49 mW·cm−2. The work provides valuable insights into the design of electrode structures for high-performance supercapacitors.

Contactless printing of food micro-particles controlled by ultrasound

Traditional food 3D printing technology, which primarily relies on mechanical control, often faces challenges such as low resolution, stringent material requirements, limited flexibility, and cumbersome equipment. To overcome these limitations, we developed an innovative food 3D printing method utilizing ultrasonic phased arrays and subsequently designed a contactless printing device employing this advanced technology. The device effectively manipulates the phase and amplitude of the ultrasonic phased array to focus the sound field on a specific location. We have successfully demonstrated preliminary control over the suspension of small food particles, including popcorn, chocolate, honey, and marshmallows, using this apparatus. Following this, popcorn particles were selected for detailed practical printing and further analysis. Additionally, we established a software platform, Ultr_printing, based on Ultraino, for intelligent simulation and control of the printing process. Leveraging FPGA and Arduino controllers, this setup facilitates rapid signal transmission from personal computers to sensors, ensuring quick and adaptable movement of suspended particles. Experimental results confirm that the device consistently controls the food particles, irrespective of their motion state. Notably, it achieves a printing precision of 0.16 mm when handling popcorn particles measuring 1.5 mm in diameter. The process, entirely contactless and free from contamination, preserves the original flavor of the food particles. This technology is particularly effective for high-precision printing of micro-scale shapes and offers considerable benefits in assembly and precision manufacturing.

Thermal-responsive soil-hydrogel composite for additive construction

To improve the formability and bonding strength of 3D printing soil, a temperature-stimulating responsive intelligent soil-hydrogel 3D printing formula was innovatively developed by combining soil and gelatin. Varied soil-gelatin composites, featuring different gelatin content by weight of soil (0 %, 0.5 %, 1 %, and 1.5 %), were prepared and cured at 5 °C to facilitate the crosslinking of gelatin. An array of tests, including rheological assessments, compressive tests, and scanning electron microscopy analysis. Were conducted to thoroughly characterize the performance of gelatin-soil composites for 3D printing. Our findings unveiled that, following the cross-linking of gelatin at 5 °C, the gelatin-soil composites exhibited superior formability and bond strength compared to the reference. Furthermore, the soil-gelatin composites demonstrated not only comparable compressive strength to the reference but also enhanced interlayer bond strength. This innovative soil-hydrogel 3D printing formula, combining the versatility of soil and the responsive characteristics of gelatin, presents a promising avenue for advancing the capabilities of 3D printed soil.

Futuristic Design of Ethnic Clothing Using 3D Technologies

The author considers the use of innovative 3D printing technologies as a tool used by modern clothing designers striving for uniqueness and a futuristic look of their products. Particular attention is paid to the prospects for introducing 3D printing into the fashion industry and the opportunities it provides for individualisation, experimentation with shapes and textures, as well as the creation of new aesthetically attractive designs. The article may be of interest to students of the creative speciality of Fashion Design, design specialists exploring modern technologies in the fashion industry, as well as for those interested in innovation and creative approach to modern and promising clothing design. 3D printing allows one to create unique and personalised products such as jewellery, patterns, accessories that meet individual needs and preferences. Designers can adapt existing patterns or create their own, which will lead to a more exclusive approach to designing clothes, accessories, and jewellery. The author's desire to draw attention to the influence of 3D printing on the cultural code sewn into ethnic decor in order to give new breath to traditional symbolism is the goal of this study. Ethnic motifs and patterns made on a 3D printer can serve as separate details of decor, as well as be elements of a clothing item itself in its various manifestations. Ethnic patterns are an important aspect of world fashion, reflecting the cultural heritage and traditions of different peoples. The identification of the degree of significance of modern technologies in the life of an artist of decorative and applied arts was the result of this study. According to the author, the introduction of 3D printing into the creative process of a designer expands their capabilities, stimulates the development of innovations, and transforms the fashion industry. The results of the study showed that 3D printing opens up unique opportunities for the creative process of a designer. However, the study also revealed a number of technical problems associated with 3D printing of clothes that need to be solved for the widespread implementation of this technology in the fashion industry. Further research and cooperation with such specialists as engineers and computer experts are necessary to fully realise the potential of 3D printing.

Innovative 3D printing and molding process for secondary-skin-collimator fabrication

Purpose. Secondary skin collimation (SSC) is essential for shielding normal tissues near tumors during electron and orthovoltage radiation treatments. Traditional SSC fabrication methods, such as crafting in-house lead sheets, are labor-intensive and produce SSCs with low geometric accuracy. This study introduces a workflow that integrated 3D scanning and 3D printing technologies with an in-house mold process, enabling the production of patient-specific SSCs within six hours. Methods. An anthropomorphic head phantom was scanned with a handheld 3D scanner. The resulting scan data was imported into 3D modeling software for design. The completed model was exported to a 3D printer as a printable file. Subsequently, molten Cerrobend was poured into the mold and allowed to set, completing the SSC production. Geometric accuracy was assessed using CT images, and the shielding effectiveness was evaluated through film dosimetry. Results. The 3D printed mold achieved submillimeter accuracy (0.5 mm) and exhibited high conformity to the phantom surface. It successfully endured the weight and heat of the Cerrobend during pouring and curing. Dosimetric analysis conducted with radiochromic film demonstrated good agreement between the measured and expected attenuation values of the SSC slab, within ±3%. Conclusions. This study presents a proof of concept for novel mold room workflows that produce patient-specific SSCs within six hours, a significant improvement over the traditional SSC fabrication process, which takes 2–3 days. The submillimeter accuracy and versatility of 3D scanning and printing technologies afford greater design freedom and enhanced delivery accuracy for cases involving irregular geometries.

Developing an innovative 3D printing platform for production of personalised medicines in a hospital for the OPERA clinical trial

Breast cancer is the most frequently diagnosed cancer in women worldwide, and non-adherence to adjuvant hormonotherapy can negatively impact cancer recurrence and relapse. Non-adherence is associated with side effects of hormonotherapy. Pharmacological strategies to mitigate the side effects include coadministration of antidepressants, however patients remain non-adherent. The aim of this work was to develop medicines containing both hormonotherapy, tamoxifen (20 mg), along with anti-depressants, either venlafaxine (37.5 or 75 mg) or duloxetine (30 or 60 mg), to assess the acceptability and efficacy of this personalised approach for mitigating tamoxifen side effects in a clinical trial. A major criterion for the developed medicines was the production rate, specified at minimum 200 dosage units per hour to produce more than 40,000 units required for the clinical trial. A novel capsule filling approach enabled by the pharmaceutical 3D printer M3DIMAKER 2 was developed for this purpose. Firstly, semi-solid extrusion 3D printing enabled the filling of tamoxifen pharma-ink prepared according to French compounding regulation, followed by filling of commercial venlafaxine or duloxetine pellets enabled by the development of an innovative pellet dispensing printhead. The medicines were successfully developed and produced in the clinical pharmacy department of the cancer hospital Gustave Roussy, located in Paris, France. The developed medicines satisfied quality and production rate requirements and were stable for storage up to one year to cover the duration of the trial. This work demonstrates the feasibility of developing and producing combined tamoxifen medicines in a hospital setting through a pharmaceutical 3D printer to enable a clinical trial with a high medicines production rate requirement.

Innovative 3D printing of mechanoluminescent composites: Vat photopolymerization meets machine learning

Mechanoluminescent (ML) materials, which refers to a class of material that emits light upon being subjected to external mechanical stimuli, have been drawing attention due to their unique multifunctionality and potential applications in next-generation structural health monitoring. However, the practical use of ML materials has been limited by the lack of a universally acceptable framework for producing high-intensity ML composites and the challenges in fabricating complex 3D shapes. As a breakthrough, this paper presents a novel approach for producing SrAl2O4:Eu2+, Dy3+ particle-based ML composites using Vat photopolymerization (VP)–based 3D printing, and its process optimization via machine learning-based algorithm. In this study, multi-objective Bayesian optimization (MBO) with Gaussian process regression (GPR) as surrogate model is adopted to fine-tune three critical process parameters in VP process: ML particle content, layer thickness, and cure ratio, aiming for both strong ML properties and reduced printing time. GPR models the complex process input-output relationship, utilizing data collected from experiments. The Pareto-optimal solutions identified by MBO not only enabled the rapid production of high-performance ML specimens but also provided empirical insights into how process parameters affect the end product’s ML property and overall printing time. Furthermore, a micromechanical method for analyzing ML particle volume fraction dependence of the ML intensity is presented to analyze the result. Finally, the practical applicability of the proposed framework was validated by testing ML-based stress sensors and mechanical components using the optimized VP process.

Additive manufacturing advancement through large-scale screw-extrusion 3D printing for precision parawood powder/PLA furniture production

In this paper, a large-scale screw-extrusion 3D printer specifically tailored for additive manufacturing applications is introduced, primarily focusing on crafting parawood powder/polylactic acid (PLA) furniture. Boasting a large build volume (700 × 700 × 700 mm3), the printer incorporates a meticulously designed screw extruder to ensure the precise feeding of composite material pellets. The investigation delves into the nuanced relationship between variations in the extruder nozzle orifice diameter and the resulting impact on the extrusion rate, directly correlating these variations with the motor speed. Additionally, the influence of the parawood powder/PLA ratio is explored through comprehensive mechanical property testing of the printed specimens. Optimal outcomes were attained with a 15 %w/w parawood powder composition, yielding an impressive ultimate strength of 54 MPa under specific printing conditions. The efficacy of the large-scale screw-extrusion 3D printer was robustly validated through the successful production of a parawood powder/PLA stacking chair, meeting the criteria stipulated in the Thai industrial standard. Furthermore, an identified parawood powder/PLA component, characterized by a rectangular cylinder with a cross-sectional area of 19.4 × 24.0 mm2, holds promising potential for versatile applications in furniture assembly. This innovative extrusion 3D printing approach, combined with meticulously optimized parameters, has unequivocal potential for manufacturing a diverse array of parawood powder/PLA furniture, elevating the value of parawood byproducts and contributing to waste reduction during processing.

Fabrication of bamboo-inspired continuous carbon fiber-reinforced SiC composites via dual-material thermally assisted extrusion-based 3D printing

Ceramic matrix composites (CMCs) structural components encounter the dual challenges of severe mechanical conditions and complex electromagnetic environments due to the increasing demand for stealth technology in aerospace field. To address various functional requirements, this study integrates a biomimetic strategy inspired by gradient bamboo vascular bundles with a novel dual-material 3D printing approach. Three distinct bamboo-inspired structural configurations Cf/SiC composites are designed and manufactured, and the effects of these different structural configurations on the CVI process are analyzed. Nanoindentation method is utilized to characterize the relationship between interface bonding strength and mechanical properties. The results reveal that the maximum flexural strength and fracture toughness reach 108.6 ± 5.2 MPa and 16.45±1.52 MPa m1/2, respectively, attributed to the enhanced crack propagation resistance and path caused by the weak fiber-matrix interface. Furthermore, the bio-inspired configuration enhances the dielectric loss and conductivity loss, exhibiting a minimum reflection loss of −24.3 dB with the effective absorption band of 3.89 GHz. This work introduces an innovative biomimetic strategy and 3D printing method for continuous fiber-reinforced ceramic composites, expanding the application of 3D printing technology in the field of CMCs.

Direct 3D printing of triple-responsive nanocomposite hydrogel microneedles for controllable drug delivery

Hydrogel microneedle patches have emerged as promising platforms for painless, minimally invasive, safe, and portable transdermal drug administration. However, the conventional mold-based fabrication processes and inherent single-functionality of such microneedles present significant hurdles to broader implementation. Herein, we have developed a novel approach utilizing a precursor solution of robust nanocomposite hydrogels to formulate photo-printable inks suitable for the direct 3D printing of high-precision, triple-responsive hydrogel microneedle patches through digital light processing (DLP) technology. The ink formulation comprises four functionally diverse monomers including 2-(dimethylamino)ethyl methacrylate, N-isopropylacrylamide, acrylic acid, and acrylamide, which were crosslinked by aluminum hydroxide nanoparticles (AH NPs) acting as both reinforcing agents and crosslinking centers. This results in the formation of a nanocomposite hydrogel characterized by exceptional mechanical strength, an essential attribute for the 3D printing of hydrogel microneeedle patches. Furthermore, this innovative 3D printing strategy facilitates facile customization of microneedle geometry and patch dimensions. As a proof-of-concept, we employed the fabricated hydrogel microneedles for transdermal delivery of bovine serum albumin (BSA). Importantly, these hydrogel microneedles displayed no cytotoxic effects and exhibited triple sensitivity to pH, temperature and glucose levels, thereby enabling more precise on-demand drug delivery. This study provides a universal method for the rapid fabrication of hydrogel microneedles with smart responsiveness for transdermal drug delivery applications.

Design, In Vitro Evaluation and In Vivo Biocompatibility of Additive Manufacturing Three-Dimensional Printing of β beta-Tricalcium Phosphate Scaffolds for Bone Regeneration

The reconstruction of bone deficiencies remains a challenge due to the limitations of autologous bone grafting. The objective of this study is to evaluate the bone regeneration efficacy of additive manufacturing of tricalcium phosphate (TCP) implants using lithography-based ceramic manufacturing (LCM). LCM uses LithaBone TCP 300 slurry for 3D printing, producing cylindrical scaffolds. Four models of internal scaffold geometry were developed and compared. The in vitro studies included cell culture, differentiation, seeding, morphological studies and detection of early osteogenesis. The in vivo studies involved 42 Wistar rats divided into four groups (control, membrane, scaffold (TCP) and membrane with TCP). In each animal, unilateral right mandibular defects with a total thickness of 5 mm were surgically performed. The animals were sacrificed 3 and 6 months after surgery. Bone neoformation was evaluated by conventional histology, radiology, and micro-CT. Model A (spheres with intersecting and aligned arrays) showed higher penetration and interconnection. Histological and radiological analysis by micro-CT revealed increased bone formation in the grafted groups, especially when combined with a membrane. Our innovative 3D printing technology, combined with precise scaffold design and efficient cleaning, shows potential for bone regeneration. However, further refinement of the technique and long-term clinical studies are crucial to establish the safety and efficacy of these advanced 3D printed scaffolds in human patients.

A novel pellet-based 3D printing of high stretchable elastomer

Elastomers, known for their high stretchability and flexibility, are widely used in high-tech applications. However, traditional manufacturing methods for elastomeric part production have limitations. 3D printing, particularly fused deposition modeling (FDM), offers a promising alternative by allowing the fabrication of customized elastomers with desired shapes and properties. Conventional filament-based FDM techniques struggle to print elastomers. This article presents a novel approach for 3D printing polyolefin elastomer (POE) using a direct pellet printing technique. A customized pellet printer with a pneumatic pressure feeding system was used that eliminates filament buckling issues commonly associated with conventional filament-based 3D printing methods. The mechanical properties and microstructure of the printed parts were analyzed to evaluate the suitability of the technique for producing high-quality elastomeric components. SEM images indicated a high-quality and accurate printing method; however, there are micro-holes between the raster due to the high shrinkage rate of POE and increasing the nozzle temperature improves the print quality. The mechanical properties of the printed samples exhibited remarkable formability, with elongation reaching up to 1965%. It is also found that as the nozzle temperature increased, the strength, elongation, and bonding between layers improved significantly. This innovative 3D printing technique has the potential for various applications such as soft robotics and wearable electronics.

3D printing of hydrogels for flexible micro‐supercapacitors

AbstractAdvances in hydrogel technology have paved the way for novel and valuable capabilities that are being applied to a diverse spectrum of energy storage applications. Hydrogels, originally renowned for their biomedical applications, are now finding translation into the energy storage domain. These versatile materials exhibit promising potential for various energy‐related applications, including but not limited to acting as highly flexible electrolytes, facilitating the development of flexible supercapacitors, and contributing to advancements in energy conversion devices. The tunable properties of hydrogels, their high ion accessibility, and desirable mechanical characteristics position them as promising candidates for enhancing the performance and efficiency of energy storage systems. In this review, we emphasize the integration of hydrogels into flexible micro‐supercapacitors through 3D printing technology, unraveling the charge transport mechanisms inherent in hydrogels. We discuss methods for developing hydrogels with enhanced physicochemical properties, such as improved mechanical strength, flexibility, and charge transport, offering new prospects for next‐generation energy storage devices. With a deeper understanding of gelation chemistry, we showcase significant progress in fabricating stimuli‐responsive, self‐healing, and highly stretchable hydrogels. Furthermore, we present compelling examples highlighting the versatility of hydrogels, including tailorable architectures, conductive nanostructures, 3D frameworks, and multifunctionalities. The application of innovative 3D printing techniques in hydrogel design is poised to yield materials with immense potential in the realm of energy storage.

Development of a simple paste for 3D printing of drug formulations containing a mesoporous material loaded with a poorly water-soluble drug

Poorly soluble drugs represent a substantial portion of emerging drug candidates, posing significant challenges for pharmaceutical formulators. One promising method to enhance the drug’s dissolution rate and, consequently, bioavailability involves transforming them into an amorphous state within mesoporous materials. These materials can then be seamlessly integrated into personalized drug formulations using Additive Manufacturing (AM) techniques, most commonly via Fused Deposition Modeling. Another innovative approach within the realm of AM for mesoporous material-based formulations is semi-solid extrusion (SSE). This study showcases the feasibility of a straightforward yet groundbreaking hybrid 3D printing system employing SSE to incorporate drug-loaded mesoporous magnesium carbonate (MMC) into two different drug formulations, each designed for distinct administration routes. MMC was loaded with the poorly water-soluble drug ibuprofen via a solvent evaporation method and mixed with PEG 400 as a binder and lubricant, facilitating subsequent SSE. The formulation is non-aqueous, unlike most pastes which are used for SSE, and thus is beneficial for the incorporation of poorly water-soluble drugs. The 3D printing process yielded tablets for oral administration and suppositories for rectal administration, which were then analyzed for their dissolution behavior in biorelevant media. These investigations revealed enhancements in the dissolution kinetics of the amorphous drug-loaded MMC formulations. Furthermore, an impressive drug loading of 15.3 % w/w of the total formulation was achieved, marking the highest reported loading for SSE formulations incorporating mesoporous materials to stabilize drugs in their amorphous state by a wide margin. This simple formulation containing PEG 400 also showed advantages over other aqueous formulations for SSE in that the formulations did not exhibit weight loss or changes in size or form during the curing process post-printing. These results underscore the substantial potential of this innovative hybrid 3D printing system for the development of drug dosage forms, particularly for improving the release profile of poorly water-soluble drugs.

Impact of mix proportions on particle bed 3D printed concrete properties

Additive manufacturing of concrete using particle-bed printing by selective binder activation is examined. This technique consists of spreading of a dry powder layer onto the build platform, selective liquid deposition to form a geometry on the layer, and repetition until complete. This enables the manufacturing of complex structural elements and eliminates the need of support structures during fabrication. A commercial liquid-jet 3D printer was modified and used along with a dry mixture of sand, cement, and a specially formulated aqueous solvent. The influence of the proportions of the dry powders, water/cement ratio, type and gradation of sand, type of cements, and additives on the strength and dimensional inaccuracy is examined. The results indicate that the CSA cement with round grain silica sand provides the best mechanical performance and surface quality. The use of a sand/cement ratio of 2.0, printed water/cement ratio of 0.151, and sand fineness modulus of 2.751 produced the best mechanical strength and dimensional accuracy. The results can be used to guide the design for this innovative 3D printing approach for concrete structural elements.

Comparative Life Cycle Assessment of molding process and 3D printing of High-Performance Long-fiber Reinforced Composites

Composite materials are widely employed to produce high-performance components. However, their usage is associated with significant environmental impacts, deriving from the constituent materials (e.g., carbon fiber and epoxy resin) and the manufacturing process. Traditional methods of composite manufacturing such as bag molding or compression molding were subjected to discussion due to their high energy requirements, related to the required heat and pressure, the use of molds and the production of composite scraps. In contrast, 3D printing presents a promising alternative, that could reduce material waste and energy consumption.This study investigates an innovative 3D printing process for high-performance composites, in particular continuous carbon fiber and thermosetting epoxy matrix, with the aim of investigating its environmental impact.A comprehensive Life Cycle Assessment (LCA) was conducted to compare the environmental footprints of traditional molding and 3D printing processes of continuous fiber composites. A wide range of factors such as energy consumption, resource utilization, greenhouse gas emissions, and waste generation was considered.The outcomes of this comparative LCA reveal a significant reduction in environmental impacts associated with the innovative 3D printing system with respect to traditional methods. These findings offer crucial insights into the sustainability of 3D printing for high-performance composites, providing a valuable decision-making tool for industries seeking eco-friendly manufacturing solutions.

Құрылыс 3D басып шығару технологиясында қалдық негізіндегі модификациялық қоспаларды пайдалану

The introduction of innovative 3D printing technologies in the construction industry makes it possible to increase the efficiency and environmental sustainability of materials. In parallel with the development of this technology, there was a need to create modification mixtures using waste materials. This study examines the use of waste-based modification additives in construction 3D printing technology. The main physico-mechanical properties and strength of fine-grained concretes formed by the method of layered extrusion show the high efficiency of using a modification mixture in the production of cements, mortars and concretes with a given complex of rheotechnological properties, depending on the composition of raw materials mixtures, interaction conditions and conditions. In the course of the study, the properties of waste materials are studied and the possibility of their use in the composition of building mixtures used for 3D printing is analyzed. Various experiments were carried out in order to determine the efficiency of waste materials and their effect on the physical and mechanical properties of building materials. As a result, it was found that waste-based modification additives contribute to increasing the strength, stability and environmental friendliness of building materials in construction 3D printing technology. It aims to provide new opportunities and solutions in the construction sector, considering the environmental benefits and economic benefits of these approaches.

Projection Micro-Stereolithography to Manufacture a Biocompatible Micro-Optofluidic Device for Cell Concentration Monitoring.

In this work, a 3D printed biocompatible micro-optofluidic (MoF) device for two-phase flow monitoring is presented. Both an air-water bi-phase flow and a two-phase mixture composed of micrometric cells suspended on a liquid solution were successfully controlled and monitored through its use. To manufacture the MoF device, a highly innovative microprecision 3D printing technique was used named Projection Microstereolithography (PμSL) in combination with the use of a novel 3D printable photocurable resin suitable for biological and biomedical applications. The concentration monitoring of biological fluids relies on the absorption phenomenon. More precisely, the nature of the transmission of the light strictly depends on the cell concentration: the higher the cell concentration, the lower the optical acquired signal. To achieve this, the microfluidic T-junction device was designed with two micrometric slots for the optical fibers' insertion, needed to acquire the light signal. In fact, both the micro-optical and the microfluidic components were integrated within the developed device. To assess the suitability of the selected biocompatible transparent resin for optical detection relying on the selected working principle (absorption phenomenon), a comparison between a two-phase flow process detected inside a previously fully characterized micro-optofluidic device made of a nonbiocompatible high-performance resin (HTL resin) and the same made of the biocompatible one (BIO resin) was carried out. In this way, it was possible to highlight the main differences between the two different resin grades, which were further justified with proper chemical analysis of the used resins and their hydrophilic/hydrophobic nature via static water contact angle measurements. A wide experimental campaign was performed for the biocompatible device manufactured through the PμSL technique in different operative conditions, i.e., different concentrations of eukaryotic yeast cells of Saccharomyces cerevisiae (with a diameter of 5 μm) suspended on a PBS (phosphate-buffered saline) solution. The performed analyses revealed that the selected photocurable transparent biocompatible resin for the manufactured device can be used for cell concentration monitoring by using ad hoc 3D printed micro-optofluidic devices. In fact, by means of an optical detection system and using the optimized operating conditions, i.e., the optimal values of the flow rate FR=0.1 mL/min and laser input power P∈{1,3} mW, we were able to discriminate between biological fluids with different concentrations of suspended cells with a robust working ability R2=0.9874 and Radj2=0.9811.

Upcycling imperfect broccoli and carrots into healthy snacks using an innovative 3D food printing approach.

Vegetables are healthy foods with nutritional benefits; however, nearly one-third of the world's vegetables are lost each year, and some of the losses happen due to the imperfect shape of the vegetables. In this study, imperfect vegetables (i.e., broccoli and carrots) were upcycled into freeze-dried powders to improve their shelf-life before they were formed into food inks for 3D printing. The rheology of the food inks, color analysis of the uncooked and cooked designs, and texture analysis of the cooked designs were determined. The inks with 50% and 75% vegetables provided the best printability and shape fidelity. 3D printing at these conditions retained a volume comparable to the digital file (14.4 and 14.3 cm3 vs. 14.6 cm3, respectively). The control, a wheat flour-based formulation, showed the lowest level of stability after 3D printing. The viscosity results showed that all the food inks displayed shear-thinning behavior, with broccoli having the greatest effect on viscosity. There was a significant color difference between uncooked and cooked samples, as well as between different formulations. The hardness of the baked 3D-printed samples was affected by the type and content of vegetable powders, where carrot-based snacks were notably harder than snacks containing broccoli. Overall, the results show that 3D food printing can be potentially used to reduce the loss and waste of imperfect vegetables.

Amelioration of interfacial properties for CGF/PA6 composites fabricated by ultrasound-assisted FDM 3D printing

Perfect interfacial adhesion is difficult to be achieved for hot-melt continuous glass fiber (CGF)/PA6 prepregs, which dilutes various physicochemical properties of samples by fused deposition modeling (FDM) technology. Herein, an innovative FDM 3D printing device with ultrasonic embedding is designed, and the influence of ultrasonic frequency on the interfacial adhesion is investigated. The introduction of ultrasound effectively enhances the interfacial adhesion between CGF and PA6, improving bonding strength not only between interlayers but also among inter-filaments. In addition, the porosity of printed samples significantly decreases from 4.52% to 1.33% with the increased ultrasonic frequency, and the mechanical properties are all ameliorated. This study provides a practical and efficient approach to solve the interface bonding problem of FDM 3D printing continuous fibers reinforced polymer samples.