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Enzymatic biocatalysis typically generates less waste, uses less water, and minimizes energy consumption compared to traditional chemical methods. Efficient, cell-free biosynthesis relies on the reuse of its valuable biocatalysts. Immobilization of enzymes on solid supports, such as enzyme carrier resins (ECRs), offers a reliable and widely deployed approach to maximize enzyme turnover in cell-free biosynthesis. We focus on two major bottlenecks associated with optimizing cell-free biocatalysis. First, we apply our lab's 3D-printed labware to screen ECRs in 96-well mini-reactors to optimize enzyme immobilization conditions. Second, we introduce inline infrared spectroscopy to monitor bioreactor output and maximize enzyme productivity. Urease provides a model system for examining immobilization conditions and continuous assessment of biocatalyst performance. As required for the high substrate concentrations to improve process efficiency and minimize waste, urease was studied in unusually high concentrations of its substrate – molar concentrations of urea. The optimized reactor processed 3.24 L of 4.00 M urea at an average volumetric productivity of 13 g ⋅ L−1 ⋅ h−1 over 18 h and achieved an estimated productivity number of >17.4 kg urea processed per g of immobilized urease Type-IX. This workflow can be generalized to most biocatalytic processes and could accelerate adoption of cell-free biosynthesis for greater chemical sustainability.

Speaking valves enable tracheostomy patients to speak naturally. However, improper use may cause dangerous overpressure, leading to severe complications or even patient's death. We address this life-threatening issue by creating a biomimetic speaking valve, which incorporates an integrated overpressure valve that automatically opens when reaching critical pressure levels. To enhance safety, we integrated a whistle module to provide an audible alert for medical staff. Fundamental research on the Utricularia vulgaris trapdoor inspired our abstracted valve form. Through a comprehensive analysis using generalized linear mixed-effect models, we examined various membrane parameter effects on the function of the biomimetic overpressure valve. This enabled us to adjust the valve's opening pressure to cater to patient's unique requirements, thus potentially saving lives by applying a solution from nature. [ABSTRACT FROM AUTHOR]

Summary: The quest for sustainable alternatives to traditional meat products has led to increased interest in plant‐based meat analogues. Microalgae, with their high protein content and eco‐friendly cultivation methods, present a promising option for the development of such analogues. However, integrating microalgae into meat analogues poses challenges related to achieving desired texture, flavour, and colour. This review explores the potential of modified starch (MS) as a solution to enhance the quality of microalgae‐based meat analogues produced via 3D printing. Key findings from the manuscript indicate that MSs can improve the viscosity, elasticity, and printability of microalgae‐based edible inks. Furthermore, they play a crucial role in reducing off‐flavours and off‐colours in the final product. By optimising the type and concentration of MSs used, microalgae‐based meat analogues can be tailored to meet consumer preferences while addressing environmental concerns. Overall, the utilisation of MSs represents a practical approach to overcoming manufacturing challenges associated with microalgal‐based meat analogues, paving the way for the development of sustainable and nutritious plant‐based meat products through innovative and ecologically friendly food technologies. [ABSTRACT FROM AUTHOR]

Background: Smoking in pregnancy continues to cause significant morbidity to mothers and babies and contributes to tremendous costs to society. Maternal-fetal attachment (MFA) may differentiate smokers who quit or pregnant smokers from non-smokers. Researchers have recommended utilizing interventions that improve MFA to help decrease smoking within pregnancy. Methods: We performed a randomized clinical trial of pregnant smokers (n = 33) using an MFA-informed, intention-to-treat protocol. We recruited pregnant smokers and provided timeline follow back (TLFB) interviews from 27 weeks of pregnancy until 6 weeks post-partum. Salivary cotinine was also collected at five different time points. 3D ultrasonography was performed, and patients were randomly assigned a 3D picture or a 3D model of their fetus. Results: Overall, the average percent reduction in cigarette use was 37.03% (SD = 31.18). The main effect of 3D type was not significant (3D Model vs. 3D Print Estimate = -0.09, 95% CI: − 0.19 to 0.01, p = 0.066). A total of 4 patients (12%) quit smoking within one week of delivery. A 10% reduction in cigarette use was associated with a 30.57 g increase in birth weight (Estimate = 30.57, 95% CI: -14.15 to 75.29); a 10% reduction in cigarette use was associated with a 0.14 week increase in estimate gestational age at delivery (Estimate = 0.14, 95% CI: -0.01 to 0.28). Conclusions: Patients who smoke in pregnancy decrease the number of cigarettes smoked after receiving either a 3D picture or 3D model of their fetus. Trial registration: clinicaltrials.gov (NCT04541121). [ABSTRACT FROM AUTHOR]

Background: The purpose of the study was to measure the degree of conversion (DC) of direct-printed aligners (DPA) that were post-cured under ambient and nitrogen atmosphere at specific time intervals and investigate the kinetics of polymerization reaction of this material. Methods: A total of 48 aligners were produced in 4 printing series by a 3D printer with TC-85DAC resin (Graphy Inc). From each series of printing, 12 aligners were included. The aligners were divided into two groups according to their post-curing conditions. One group was post-cured under ambient air with the presence of oxygen and the other under a nitrogen atmosphere, both using the same UV post-curing unit recommended by the company. The aligners were post-cured at six different time intervals: 1, 2, 3, 5, 10, and 20 min. Each time interval included 8 aligners, with 2 aligners from each series. The DC of the cured aligners was measured by means of attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) through acquisition of the respective spectra for each UV-curing condition. Statistical analysis was performed to compare the results and differences within each atmosphere post-curing protocol, as well as between the different selected atmosphere conditions. Statistical significance level was set at p-value ≤ 0.05. Results: Pairwise analysis between post-curing protocols showed statistically significant differences only at the first minute of polymerization. Post-curing with nitrogen did not yield statistically significant results across different time intervals. Post-curing in ambient air showed some significant differences on the 1st and 2nd minute of the post-curing process. Conclusions: Almost complete double bond conversion was observed. Significant differences were observed only during the first minute of polymerization under the nitrogen atmosphere. [ABSTRACT FROM AUTHOR]

This paper presents a 3D-printed fully dielectric bi-material reflectarray with bandgap characteristics for multi-band applications. To achieve bandgap characteristics, a "1D Bragg reflector" unit cell is used. The latter is a layered structure characterized by a spatial distribution of refractive index that varies periodically along one dimension. By appropriately selecting the dimensions, the bandgap can be shifted to cover the desired frequency bands. To validate this bandgap characteristic, a (121.5 mm × 121.5 mm) with an f/D ratio of 0.5 reflectarray was fabricated. The measured gain at 27 GHz is 27.22 dBi, equivalent to an aperture efficiency of 35.05%, demonstrating good agreement between simulated and measured performances within the frequency range of 26–30 GHz. Additionally, the transparency of the reflectarray was verified by measuring the transmission coefficient, which exhibited a high level of transparency of 0.32 dB at 39 GHz. These features make the proposed reflectarray a good candidate for multi-band frequency applications. [ABSTRACT FROM AUTHOR]

Clear aligner therapy is a rapidly developing orthodontic treatment. 3D-printing technology, which enables the creation of complex geometric structures with high precision, has been used in dentistry. This article aims to summarize the various aspects of 3D-printing clear aligners and give an outlook on their future development. The traditional thermoforming technology is introduced and the principle and application of 3D-printed clear aligners and materials are introduced, as well as the application prospects of 3D-printed clear aligners. According to PRISMA statement, the relevant literature of 3D-printing clear aligner was searched in PubMed, Web of Science, Embase and other databases. We searched the related words in the MESH database and then carried out advanced searches. We read systematic review and conference papers to find the articles related to the subject and manually added and excluded articles by reading the title and abstract. The production of clear aligners combines computer-aided 3D analysis, personalized design and digital molding technology. The thickness and edges of the 3D-printed clear aligner can be digitally controlled, which allows appliance more efficiently fitted. Presently, the array of clear resins suitable for 3D-printing include photo polymeric clear methacrylate-based resin (Dental LT) (Form Labs, Somerville, Mass), aliphatic vinyl ester-polyurethane polymer (Tera Harz TC-85) (Graphy, Seoul, South Korea). They all have good biocompatibility. But no such material is currently approved on the market. Developing biocompatible resins and further improving the material's mechanical properties will be critical for the combination of 3Dprinting and clear aligners. However, the literature on 3D-printed clear aligners is limited and lacks clinical application. Further in vivo and in vitro tests, as well as additional exploration in conjunction with corresponding cytological tests, are required for the research on available materials and machinery for 3D-printing clear aligners. [ABSTRACT FROM AUTHOR]

Fused Filament Fabrication is a promising manufacturing technology for the circularity of space missions. Potential scenarios include in‐orbit applications to maximize mission life and to support long‐term exploration missions with in situ manufacturing and recycling. However, its adoption is restricted by the availability of engineering polymers displaying mechanical performance combined with resistance to space conditions. Here, a thermotropic Liquid Crystal Polymer (LCP) is reported as a candidate material with extrusion 3D printing. To expand its scope of applicability to structural parts for space applications, four different exposure conditions are studied: thermal cycling under vacuum, atomic oxygen, UV, and electron irradiations. While 1 MeV‐electron irradiation leads to a green coloration due to annealable color centers, the mechanical performance is only slightly decreased in dynamic mode. It is also found that increased printing temperature improves transverse strength and resistance to thermal cycling with the trade‐off of tensile stiffness and strength. Samples exposed to thermal cycling and the highest irradiation dose at lower printing temperatures still display a Young's modulus of 30 GPa and 503 MPa of tensile strength which is exceptionally high for a 3D‐printed polymer. For the types of exposure studied, overall, the results indicate that LCP 3D‐printed parts are well suited for space applications. [ABSTRACT FROM AUTHOR]

Organogels are polymer networks extended by a liquid organic phase, offering a wide range of properties due to the many combinations of polymer networks, solvents, and shapes achievable through 3D printing. However, current printing methods limit solvent choice and composition, which in turn limits organogels' properties, applications, and potential for innovation. As a solution, a method for solvent‐independent printing of 3D organogel structures is presented. In this method, the printing step is decoupled from the choice of solvent, allowing access to the full spectrum of solvent diversity, thereby significantly expanding the range of achievable properties in organogel structures. With no changes to the polymer network, the 3D geometry, or the printing methodology itself, the choice of solvent alone is shown to have an enormous impact on organogel properties. As demonstrated, it can modulate the thermo‐mechanical properties of the organogels, both shifting and extending their thermal stability range to span from ‐30 to over 100 °C. The choice of solvent can also transition the organogels from highly adhesive to extremely slippery. Finally, the method also improves the surface smoothness of prints. Such advances have potential applications in soft robotics, actuators, and sensors, and represent a versatile approach to expanding the functionality of 3D‐printed organogels. [ABSTRACT FROM AUTHOR]

This article explores the use of 3D printing technology in architectural restoration, specifically focusing on the optimization of the internal structure of 3D-printed components. The study investigates the structural performance of 3D-printed elements made of PLA material through experimental and numerical analyses. The findings highlight the influence of different internal structure configurations on the mechanical properties of the printed parts. The article also discusses the implications of these findings for the design process and potential applications of 3D printing in architectural restoration. Overall, this research contributes to the broader field of 3D printing technology for cultural heritage preservation. [Extracted from the article]

[Display omitted] • Spinal cord injury damages axons, causing loss of motor and sensory function. • Promoting and guiding axonal regrowth is essential for functional recovery. • 3D-printed, electroconductive scaffolds with tuneable geometries were developed. • Scaffolds were functionalised with aligned, neurotrophic extracellular matrix. • Electrostimulation via scaffolds significantly increased outgrowth from neurons. Spinal cord injury (SCI) is a devastating neurotrauma, affecting 250,000 to 500,000 people annually, and typically results in paralysis. Electrostimulation can promote neuronal growth, but the formation of a lesion cavity post-SCI inhibits regrowth, limiting its efficacy. Bridging the lesion with a structured, electroactive substrate to direct electrostimulation to growing neurites could support and drive neuronal regrowth through the lesion to enable functional recovery but to date, no such platform exists. This study describes the development of an electroconductive (15 ± 5 S/m), 3D-printed scaffold, comprising a polypyrrole/polycaprolactone framework filled with biomimetic & neurotrophic extracellular matrix. 3D printing allowed inclusion of channels in the scaffold designed to mimic the size of human corticospinal tracts to direct electrostimulation to growing neurons. Scaffolds exhibited excellent biocompatibility with both neurons and human primary astrocytes and maintained electrical and biofunctionality when scaled to match the size of human corticospinal tracts. When neurons were cultured for 7 days on the scaffolds under continuous electrostimulation (200 mV/mm, 12 Hz), significantly longer neurites were observed on electrically stimulated electroconductive scaffolds. These results demonstrate that electrostimulation applied via an anatomically-mimetic, 3D-printed electroconductive scaffold drives neurite outgrowth and represents a promising approach for treatment of spinal cord injury. [ABSTRACT FROM AUTHOR]

Background and Objectives: Advances in dental materials and CAD-CAM technology have expanded crown options in primary teeth due to their improved appearance and mechanical properties. Thus, this study aimed to assess the enamel wear and fracture resistance of prefabricated, milled, and 3D-printed esthetic pediatric crowns. Materials and Methods: The study involved 60 extracted maxillary second primary molars and 60 3D-printed resin dies, divided into six groups based on different crown materials (n = 10): prefabricated zirconia, prefabricated composite, milled composite, milled resin matrix ceramic, milled PEEK, and 3D-printed resin. Prefabricated crowns were selected after the preparation of the typodont mandibular second primary molar tooth, while milled and 3D-printed crowns were custom produced. The specimens underwent mechanical loading of 50 N at 1.6 Hz for 250,000 cycles with simultaneous thermal cycling. The 3D and 2D wear amounts were evaluated by scanning the specimens before and after aging. Then, the fracture resistance and failure types of the restorations were recorded. Results: The results showed that the milled PEEK group had superior fracture resistance compared to the other groups, while prefabricated zirconia crown group had the lowest value. Milled resin matrix ceramic crown group displayed the lowest 3D wear volume, while 3D-printed crown group showed the highest 2D wear. Conclusions: The restorative material type did not have a significant effect on the wear of primary tooth enamel. The fracture resistance of the tested materials differed according to the material type. Although the milled PEEK group showed the highest fracture resistance, all tested materials can withstand chewing forces in children. [ABSTRACT FROM AUTHOR]

Geopolymers (GPs) are emerging, low‐density ceramic materials that are simple to manufacture, with high elastic modulus and strength, albeit with low toughness. Fiber reinforcements have been used to achieve varied ductile behaviors, but little is known about the GP addition to polymeric frame structures. Thus, drawing inspiration from the nanostructure of bones, this paper investigated an interpenetrating, co‐continuous composite consisting of a GP as the stiff but brittle phase, and a 3D‐printed polymer (PA12 White) as the soft and deformable phase. The composite mechanical properties and failure modes were studied experimentally using uniaxial compression and four‐point bending tests. The co‐continuous network constrained brittle cracking within the GP and reduced strain localization in the polymer. The results showed that the composite had higher strength (56.11 ± 2.12 MPa) and elastic modulus (6.08 ± 1.37 GPa) than the 3D‐printed polymer and had higher toughness (5.98 ± 0.24 MJ/mm3) than the GP for the specific geometries examined. The shape effect study demonstrated that cubic structures had higher elastic modulus and strength but at the expense of lower toughness when compared to rectangular prism structures. The study of scale effects indicated that increasing the number of periodic unit cells while maintaining consistent bulk dimensions led to augmented strength and toughness, albeit without statistically significant alterations in elastic modulus. Thus, this paper presents an experimental realization of a novel, bio‐inspired, interpenetrating, GP–polymer composite design, offering improved strength and toughness. It also provides valuable insights into the shape and size effects on the mechanical properties of this new composite. [ABSTRACT FROM AUTHOR]

Background: Accurate diagnosis and treatment of complex cardiac tumors poses challenges, particularly when surgical resection is considered. 3D reconstruction and printing appear as a novel approach to allow heart teams for optimal surgical and post operative care. Methods: We report two patients with uncommon masses including a cardiac angiosarcoma (CAS) and a IgG4-related disease (IgG4-RD) with exclusive cardiac involvement. In both cases, three-dimensional (3D) reconstruction and 3D-printed models were utilized to aid the surgical team achieve optimal pre-operative planning. Both patients underwent ECG-gated cardiac computed tomography angiography (CCTA) imaging and, due to the complex anatomy of the masses, their large dimensions, proximity to vital cardiac and vascular structures, and unclear etiology, computational and 3D-printed models were created for surgical planning. An exploratory literature review of studies using 3D-printed models in surgical planning was performed. Results: In case 1 (CAS), due to the size and extension of the mass to the right ventricular free wall, surgical intervention was not considered curative and, during thoracotomy, an open biopsy confirmed the imaging suspicion of CAS which guided the initiation of optimal medical treatment with chemotherapy and, after clear tumor retraction, the patient underwent a second surgical intervention, and during the 18 months of follow-up showed no signs of recurrence. In Case 2 (IgG4-RD), the patient underwent uncomplicated total surgical resection; this allowed directed treatment and, at 12 months follow-up, there are no signs of recurrence. Computational and 3D-printed models were used to plan the surgery and to confirm the findings. Limited studies have explored the use of 3D printing in the surgical planning of tumors. Conclusions: We present two patients with uncommon cardiac tumors, highlighting the significant value of 3D models in the anatomical characterization and assessment of their extension. These models may be essential in surgical planning for complex cardiovascular cases and could provide more information than conventional imaging modalities. Further studies are needed to demonstrate the impact of 3D technologies in studying cardiac tumors. [ABSTRACT FROM AUTHOR]

Background: The Trident II Tritanium acetabular shell is additively manufactured (3D printed), based on the established Trident 'I' Tritanium shell, produced using conventional methods; this study characterised their differences. Methods: We obtained 5 Trident I (T1) and 5 Trident II (T2) shells sized 52 mm, 54 mm (n = 3) and 60 mm. We measured their: mass, shell-liner engaging surface roughness, roundness, wall thickness, the depth of the bone-facing porous layer, porosity, and the number, volume and location of structural voids. Results: The mass varied by up to 13.44 g. The T1 and T2 shells had a median internal roughness of 0.18 μm and 0.43 μm, (p < 0.001) and the median departure from roundness was 6.9 μm and 8.9 μm, (p < 0.001). The 54 mm and 60 mm T2 shell walls were 37% and 29% thinner than their T1 counterparts (p < 0.01). The T2 shells had irregular porous structures, shallower in depth by 11–27% (p < 0.001) than T1 shells, which had repeating mesh units; the overall porosity was comparable (54%). All T2 shells had between 115 and 3415 structural voids, compared with two T1 shells containing 21 and 31 voids. There was no difference in the depth of the porous layer for the 54 mm T2 shells (p = 0.068), whilst T1 shells did show variability (p < 0.01). Both groups showed a variability in surface roughness and roundness (p < 0.01). Conclusion: This is the first study to compare shells from a single manufacturer, produced using conventional and additive methods. This data will help interpret the performance of the 3D printed Trident II as longer-term clinical data is generated. [ABSTRACT FROM AUTHOR]

ABSTRACT Purpose Materials and Methods Results Conclusions To evaluate the dimensional stability over time of additively manufactured surgical templates, fabricated by different resins, and stored by different methods.Using a 3D printer with DLS technology and two different resins (Surgical Guide (SG)‐WhipMix and Key Guide (KG)‐KeystoneIndustries), 96 surgical guides were additively manufactured. The guides were stored in three different environments: directly exposed to sunlight (S1), in normal interior room conditions (S2), and in darkness (S3). The guides were digitally scanned immediately after fabrication and post‐processing, and after 1, 3, and 6 months of storage. For each group, the mean deviation of the root mean square (RMS) between guide's intaglio surface, as well as the axial deviation between sleeves' housings were calculated.The mean axial variations of angular axis deviation of sleeves' housings ranged between 0.09° and 3.99°. The mean deviation of the RMS discrepancy in guide's intaglio ranged from 0.1 to 0.18 mm. Variations were significant (p < 0.001) only for the S1 group and only for SG material. After 3 months, an additional storage time of 3 months did not have any further effect on dimensional stability.Within the limitations of the present study, storage time of a surgical guide for up to 3 months after manufacturing, as well as printing material can significantly affect surgical guide's dimensional stability, when they are exposed to direct or indirect sunlight conditions. Storage of guides in a dark environment is recommended in order to avoid an additional source of error in computer‐guided surgery workflows. [ABSTRACT FROM AUTHOR]

Objective: Miniplates offer superior clinical handling and facilitate postoperative removal after mandibular reconstruction but unfavorable load distribution under high stress has been shown. This study aimed to compare the clinical outcome of patient-specific 3D-printed (PS-3D) titanium miniplate with reconstruction plate fixation in three-segmental LCL-type reconstructions for the first time. Methods: Patients undergoing three-segmental LCL-type mandibular reconstruction after malignant tumor resection between April 2017 and July 2023 were analyzed in a retrospective single-center study. Inclusion criteria were primary reconstruction using a fibula free flap and PS-3D titanium mini- or reconstruction plate fixation. Complication rates were recorded and analyzed within 6 months after surgery using the N -- 1 Chi²- and unequal variance t-test. Results: 38 patients (10 females, 28 males; mean age 61.4 ± 7.6 years) met the inclusion criteria. In 14 patients (36.8%) miniplates were used in the anterior region. Rates of fixation failure, plate exposure, incomplete osseous union, wound infection, soft tissue, and overall complications did not differ significantly between the two plate systems. Conclusion: Complication rates did not differ significantly between PS-3D miniand reconstruction plates in three-segmental LCL-type mandibular reconstructions. Given their advantages in clinical handling and postoperative removal, PS-3D miniplates can be a viable alternative also in larger mandibular reconstructio [ABSTRACT FROM AUTHOR]

We report the use of wet‐spinning to 3D‐print gels from low‐molecular‐weight gelators (LMWGs) based on the 1,3 : 2,4‐dibenzylidenesorbitol (DBS) scaffold. Gel stripes assembled from DBS‐CONHNH2 and DBS‐COOH are printed, and their conductivities assessed. Printed gels based on DBS‐CONHNH2 can be loaded with Au(III), which is reduced in situ to form embedded gold nanoparticles (AuNPs). The conductivity of these gels increases because of electron transport mediated by the AuNPs, whereas the conductivity of DBS‐COOH, which does not promote AuNP formation, remains lower. We then fabricate multi‐component gel patterns comprised of spatially well‐defined domains of printed DBS‐CONHNH2/AuNP (higher conductivity) and DBS‐COOH (lower conductivity) resulting in soft multi‐domain materials with differential conductivity. Such materials have future prospects in applications such as soft nanoelectronics or tissue engineering. [ABSTRACT FROM AUTHOR]

Low‐cost direct air capture (DAC) systems require efficient gas–solid contactors. These contactors provide rapid rates of heat and mass transport with minimal pressure drops. Triply periodic minimal surfaces (TPMS) are a class of geometries that are shown to have heat transfer properties that exceed those of other geometries, and these benefits are expected to manifest in mass transfer as well due to the analogies between heat and mass transfer. However, creating TPMS contactors is difficult using conventional manufacturing techniques such as injection molding. Non‐solvent‐induced phase separation (NIPS) of a polymeric ink containing the adsorbent is one way to construct adsorption contactors with excellent mass transport rates, but contactors have to date only been fabricated in simple geometries (e.g., films, fibers). This study demonstrates that NIPS of polymeric inks occurs within a simultaneously‐dissolving, water‐soluble, 3D‐printed template. This templated phase inversion (TPI) technique can create seemingly unlimited macroscopic architectures, including TPMS contactors, using a variety of potential DAC adsorbents, including zeolite, silica, activated carbon, and metal–organic frameworks. SEM, micro‐computed tomography, and nitrogen adsorption experiments reveal the microscopic pore structures and macroscopic geometries of the resulting sorbent contactors. TPMS DAC contactors with poly(ethyleneimine)/silica adsorbents are shown to have CO2 capture performances that rival or exceed other contactor geometries. [ABSTRACT FROM AUTHOR]

Lunar regolith is the most abundant resource on the lunar surface, which can be used for in-situ fabrication and repair technologies. Vat photopolymerization-based additive manufacturing is among the most promising techniques, capable of producing precise ceramic parts of complex shapes from the lunar regolith feedstock for the needs of future crewed exploration missions to the Moon. One of the under-studied aspects of additive manufacturing with lunar regolith is the pre-and post-treatment procedures, which would ensure optimal energy and material consumption and the best printing performance. The goal of the present article was to define the influence of the mineral composition of lunar regolith simulants and the parameters of their pre-processing on the properties of sintered regolith ceramics. It was found that the highland regolith could be sintered to higher relative density compared to the mare regolith. The optimal sintering temperature was determined to be 1150 °C for both types of lunar regolith. An optimal mineral and fractional composition for the regolith feedstock was determined based on the trade-off analysis between lunar regolith sinterability and its printability via vat photopolymerization-based additive manufacturing. Vat-polymerization was performed to produce complex-shaped ceramic parts, yielding 95 % of relative density and a mean ultimate flexural strength of 106 ± 5 MPa, confirming the proposed trade-off point. [ABSTRACT FROM AUTHOR]

Stereolithography enables the fabrication of three-dimensional (3D) freeform structures via light-induced polymerization. However, the accumulation of ultraviolet dose within resin trapped in negative spaces, such as microfluidic channels or voids, can result in the unintended closing, referred to as overcuring, of these negative spaces. We report the use of injection continuous liquid interface production to continuously displace resin at risk of overcuring in negative spaces created in previous layers with fresh resin to mitigate the loss of Z-axis resolution. We demonstrate the ability to resolve 50-µm microchannels, breaking the historical relationship between resin properties and negative space resolution. With this approach, we fabricated proof-of-concept 3D free-form microfluidic devices with improved design freedom over device material selection and resulting properties. [ABSTRACT FROM AUTHOR]

A multifunctional, multiphase-supported photocatalyst was fabricated via the combination of LCD three-dimensional (3D) printing, cold plasma discharge (CPD) technology, and surface chemistry to be used for the degradation of organic pollutants in water and for the generation of hydrogen gas. BiOBr was chosen as the main catalytic phase and was used in association with a phosphor, SrAl2O4:Eu2+,Dy3+ (SAED), and a metal–organic framework, Ni-BDC. Their immobilization was realized thanks to polydopamine (PDA), which is used as a coupling agent. While BiOBr was the most active photocatalytic phase, the phosphor acted as a light-storing component for photodegradation in the dark and overall, as a boost for photoactivity. PDA also boosted the photoactivity, in parallel with its crucial role in the immobilization of the SAED/Ni-MOF/BiOBr catalyst on fractal polymer support. An in situ complexation-assisted precipitation (ISCAP) process was used, allowing the formation of the catalytic phases with nano features. The resulting hybrid photocatalysts were tested through rhodamine B (RhB) dye photodegradation upon visible light irradiation or light/dark alternating conditions to simulate more realistic variable light illumination. We found that, although used in a very small amount, the Ni-MOF had a significant impact on the photoactivity, forming a Z-scheme heterojunction with BiOBr. Finally, H2 evolution testing further established the photocatalytic activity and versatility of the supported catalysts. [ABSTRACT FROM AUTHOR]

Cardiac tissue engineering has been rapidly evolving with diverse applications, ranging from the repair of fibrotic tissue caused by "adverse remodeling," to the replacement of specific segments of heart tissue, and ultimately to the creation of a whole heart. The repair or replacement of cardiac tissue often involves the development of tissue scaffolds or constructs and the subsequent assessment of their performance and functionality. For this, the design and/or selection of biomaterials, and cell types, scaffold fabrication, and in vitro characterizations are the first starting points, yet critical, to ensure success in subsequent implantation in vivo. This highlights the importance of scaffold fabrication and in vitro experiments/characterization with protocols for cardiac tissue engineering. Yet, a comprehensive and critical review of these has not been established and documented. As inspired, herein, the latest development and advances in scaffold fabrication and in vitro characterization for cardiac tissue engineering are critically reviewed, with focus on biomaterials, cell types, additive manufacturing techniques for scaffold fabrication, and common in vitro characterization techniques or methods. This article would be of benefit to the ones who are working on cardiac tissue engineering by providing insights into the scaffold fabrication and in vitro investigations. [ABSTRACT FROM AUTHOR]

The main task of this work is the optimization of the manufacturing process of Al-alloy lattice cellular structures with rhombic cell, obtained with lost-PLA technique. It is an easy, environment sustainable and economical technique (both for infrastructure and operating costs) for the manufacturing of Al porous structure based on the 3D printing of PLA and replication process alternative to that based on expensive metal 3D printers. Plaster processing, PLA burnout and AA 6082 alloy casting conditions and parameters have been suitably tuned in order to get final samples with geometry and surface finishing conditions identical to the starting ones made in PLA. A good replication process has been implemented with a high repeatability rate and accurate surface finishing, comparable with that of the PLA printed objects. Morphological analysis on PLA and Al 6082 was conducted as well microstructural analysis and Vickers microhardness tests on Al alloy samples in the as-cast conditions. Metallography reveals the presence of AlFeSi and AlFeMnSi intermetallic phases at the cell boundaries and some coarse precipitates Mg2Si in the AA 6082 alloy. Microstructures and HV measured values are aligned with literature data for this alloy in the same (as-cast) conditions. [ABSTRACT FROM AUTHOR]

Achieving precise control of nanoparticle size while maintaining consistency and high uniformity is of paramount importance for improving the efficacy of nanoparticle-based therapies and minimizing potential side effects. Although microfluidic technologies are widely used for reliable nanoparticle synthesis, they face challenges in meeting critical homogeneity requirements, mainly due to imperfect mixing efficiency. Furthermore, channel clogging during continuous operation presents a significant obstacle in terms of quality control, as it progressively impedes the mixing behavior necessary for consistent nanoparticle production for therapeutic delivery and complicates the scaling-up process. This study entailed the development of a 3D-printed novel micromixer embedded with hemispherical baffle microstructures, a dual vortex mixer (DVM), which integrates Dean vortices to generate two symmetrical counter-rotating intensified secondary flows. The DVM with a relatively large mixer volume showed rapid mixing characteristics even at a flow rate of several mL min−1 and produced highly uniform lipids, liposomes, and polymer nanoparticles in a size range (50–130 nm) and polydispersity index (PDI) values below 0.15. For the evaluation of products, SARS-CoV-2 Spike mRNA-loaded lipid nanoparticles were examined to verify protein expression in vitro and in vivo using firefly luciferase (FLuc) mRNA. This showed that the performance of the system is comparable to that of a commercial toroidal mixer. Moreover, the vigorous in-situ dispersion of nanoparticles by harnessing the power of vortex physically minimizes the occurrence of aggregation, ensuring consistent production performance without internal clogging of a half-day operation and facilitating quality control of the nanoparticles at desired scales. Dual vortex mixer enables the long-term production of highly-uniform nanoparticles with consistent properties. [Display omitted] [ABSTRACT FROM AUTHOR]

High dose-rate (HDR) brachytherapy is integral for the treatment of numerous cancers. Preclinical studies involving HDR brachytherapy are limited. We aimed to describe a novel platform allowing multi-modality studies with clinical HDR brachytherapy and external beam irradiators, establish baseline dosimetry standard of a preclinical orthovoltage irradiator, to determine accurate dosimetric methods. A dosimetric assessment of a commercial preclinical irradiator was performed establishing the baseline dosimetry goals for clinical irradiators. A 3D printed platform was then constructed with 14 brachytherapy channels at 1cm spacing to accommodate a standard tissue culture plate at a source-to-cell distance (SCD) of 1 cm or 0.4 cm. 4-Gy CT-based treatment plans were created in clinical treatment planning software and delivered to 96-well tissue culture plates using an Ir192 source or a clinical linear accelerator. Standard calculation models for HDR brachytherapy and external beam were compared to corresponding deterministic model-based dose calculation algorithms (MBDCAs). Agreement between predicted and measured dose was assessed with 2D-gamma passing rates to determine the best planning methodology. Mean (±standard deviation) and median dose measured across the plate for the preclinical irradiator was 423.7 ± 8.5 cGy and 430.0 cGy. Mean percentage differences between standard and MBDCA dose calculations were 9.4% (HDR, 1 cm SCD), 0.43% (HDR, 0.4 cm SCD), and 2.4% (EBRT). Predicted and measured dose agreement was highest for MBDCAs for all modalities. A 3D-printed tissue culture platform can be used for multi-modality irradiation studies with great accuracy. This tool will facilitate preclinical studies to reveal biologic differences between clinically relevant radiation modalities. [ABSTRACT FROM AUTHOR]

The mechanical response and fracture behavior of two architected 3D-printed hardened cement paste (hcp) elements, 'lamellar' and 'Bouligand', were investigated under uniaxial compression. A lab-based X-ray microscope was used to characterize the post-fracture crack pattern. The mechanical properties and crack patterns were analyzed and compared to cast hcp. The role of materials architecture and 3D-printing-induced weak interfaces on the mechanical properties and fracture behavior are discussed. The pore architecture that inadvertently forms in the design of solid architected materials dictated the overall mechanical response and fracture behaviors in both 3D-printed architected materials. While no specific crack pattern or microcracking was observed in the cast element, lamellar architecture demonstrated a crack pattern following weak vertical interfaces. Bouligand architectures, on the other hand, exhibited a helical crack pattern with distributed interfacial microcracking aligned with the helical orientation of filaments. As a result, the bouligand architected elements showed a significant 40% increase in work-of-failure compared to cast counterparts. The enhanced energy absorption was obtained without sacrificing the strength and was attributed to higher fractured surface and microcracking, both of which follow the weak helical interfaces. [ABSTRACT FROM AUTHOR]

Background/Objective: Repair of long bone defects remains a major challenge in clinical practice, necessitating the use of bone grafts, growth factors, and mechanical stability. Hence, a combination therapy involving a 3D-printed polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP) scaffold coated with polydopamine (PDA) and alginate microbeads (AM) for sustained delivery of bone morphogenetic protein-2 (BMP-2) was investigated to treat long bone segmental defects. Methods: Several in vitro analyses were performed to evaluate the scaffold osteogenic effects in vitro such as PDA surface modification, namely, hydrophilicity and cell adhesion; cytotoxicity and BMP-2 release kinetics using CCK-8 assay and ELISA, respectively; osteogenic differentiation in canine adipose-derived mesenchymal stem cells (Ad-MSCs); formation of mineralized nodules using ALP staining and ARS staining; and mRNA expression of osteogenic differentiation markers using RT-qPCR. Bone regeneration in femoral bone defects was evaluated in vivo using a rabbit femoral segmental bone defect model by performing radiography, micro-computed tomography, and histological observation (hematoxylin and eosin and Masson's trichrome staining). Results: The PDA-coated 3D-printed scaffold demonstrated increased hydrophilicity, cell adhesion, and cell proliferation compared with that of the control. BMP-2 release kinetics assessment showed that BMP-2 AM showed a reduced initial burst and continuous release for 28 days. In vitro co-culture with canine Ad-MSCs showed an increase in mineralization and mRNA expression of osteogenic markers in the BMP-2 AM group compared with that of the BMP-2-adsorbed scaffold group. In vivo bone regeneration evaluation 12 weeks after surgery showed that the BMP-2 AM/PDA group exhibited the highest bone volume in the scaffold, followed by the BMP-2/PDA group. High cortical bone connectivity was observed in the PDA-coated scaffold groups. Conclusion: These findings suggest that the combined use of PDA-coated 3D-printed bone scaffolds and BMP-2 AM can successfully induce bone regeneration even in load-bearing bone segmental defects. The translational potential of this article: A 3D-printed PCL/β-TCP scaffold was fabricated to mimic the cortical bone of the femur. Along with the application of PDA surface modification and sustained BMP-2 release via AM, the developed scaffold could provide suitable osteoconduction, osteoinduction, and osteogenesis in both in vitro settings and in vivo rabbit femoral segmental bone defect models. Therefore, our findings suggest a promising therapeutic option for treating challenging long bone segmental defects, with potential for future clinical application.

Abstract Background Smoking in pregnancy continues to cause significant morbidity to mothers and babies and contributes to tremendous costs to society. Maternal-fetal attachment (MFA) may differentiate smokers who quit or pregnant smokers from non-smokers. Researchers have recommended utilizing interventions that improve MFA to help decrease smoking within pregnancy. Methods We performed a randomized clinical trial of pregnant smokers (n = 33) using an MFA-informed, intention-to-treat protocol. We recruited pregnant smokers and provided timeline follow back (TLFB) interviews from 27 weeks of pregnancy until 6 weeks post-partum. Salivary cotinine was also collected at five different time points. 3D ultrasonography was performed, and patients were randomly assigned a 3D picture or a 3D model of their fetus. Results Overall, the average percent reduction in cigarette use was 37.03% (SD = 31.18). The main effect of 3D type was not significant (3D Model vs. 3D Print Estimate = -0.09, 95% CI: − 0.19 to 0.01, p = 0.066). A total of 4 patients (12%) quit smoking within one week of delivery. A 10% reduction in cigarette use was associated with a 30.57 g increase in birth weight (Estimate = 30.57, 95% CI: -14.15 to 75.29); a 10% reduction in cigarette use was associated with a 0.14 week increase in estimate gestational age at delivery (Estimate = 0.14, 95% CI: -0.01 to 0.28). Conclusions Patients who smoke in pregnancy decrease the number of cigarettes smoked after receiving either a 3D picture or 3D model of their fetus. Trial registration clinicaltrials.gov (NCT04541121).

Abstract Background The purpose of the study was to measure the degree of conversion (DC) of direct-printed aligners (DPA) that were post-cured under ambient and nitrogen atmosphere at specific time intervals and investigate the kinetics of polymerization reaction of this material. Methods A total of 48 aligners were produced in 4 printing series by a 3D printer with TC-85DAC resin (Graphy Inc). From each series of printing, 12 aligners were included. The aligners were divided into two groups according to their post-curing conditions. One group was post-cured under ambient air with the presence of oxygen and the other under a nitrogen atmosphere, both using the same UV post-curing unit recommended by the company. The aligners were post-cured at six different time intervals: 1, 2, 3, 5, 10, and 20 min. Each time interval included 8 aligners, with 2 aligners from each series. The DC of the cured aligners was measured by means of attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) through acquisition of the respective spectra for each UV-curing condition. Statistical analysis was performed to compare the results and differences within each atmosphere post-curing protocol, as well as between the different selected atmosphere conditions. Statistical significance level was set at p-value ≤ 0.05. Results Pairwise analysis between post-curing protocols showed statistically significant differences only at the first minute of polymerization. Post-curing with nitrogen did not yield statistically significant results across different time intervals. Post-curing in ambient air showed some significant differences on the 1st and 2nd minute of the post-curing process. Conclusions Almost complete double bond conversion was observed. Significant differences were observed only during the first minute of polymerization under the nitrogen atmosphere.

RELEVANCE. Despite the development of modern diagnostic methods, osteosynthesis instruments and rehabilitation, surgical management of distal tibia fractures remains a great problem due to the high complication rate leading to permanent disability, such as problems with soft tissue healing, infectious complications, post-traumatic arthrosis of the ankle joint. These complications are associated with the high incidence of high-energy injuries, soft-tissue envelope features, and the wide range of movements in the ankle joint. At the same time, in the treatment for comminuted intra-articular pilon fractures, there is no clearly defined operation algorithm: choice of access, reduction and fixation techniques. Recently, when planning osteosynthesis, additive technologies have become increasingly widespread, in particular, 3D printing of full-size fracture prototypes. AIM OF STUDY. To analyze preoperative planning methods of osteosynthesis in pilon fractures and evaluate 3D-printing for the improvement of surgical treatment of pilon fractures. MATERIAL AND METHODS. The literature search was carried out in the databases of medical publications: PubMed, eLibrary, Cyberleninka. The search was performed using the following terms: pilon fractures, osteosynthesis, preoperative planning, 3D-printing, 3D-model, and the corresponding terms in Russian. RESULTS. According to various authors, the use of 3D printing in preoperative planning improves the parameters of operative duration, reduction quality, functional outcome, intraoperative blood loss, and reduces the number of complications. CONCLUSIONS. Evaluation of the long-term results of using 3D printing in preoperative planning for osteosynthesis in pilon fractures is ongoing. But even now we can draw conclusions about the prospects of the method and recommend it for widespread use in the routine practice of the orthopedic traumatologist.

Abstract Background The Trident II Tritanium acetabular shell is additively manufactured (3D printed), based on the established Trident ‘I’ Tritanium shell, produced using conventional methods; this study characterised their differences. Methods We obtained 5 Trident I (T1) and 5 Trident II (T2) shells sized 52 mm, 54 mm (n = 3) and 60 mm. We measured their: mass, shell-liner engaging surface roughness, roundness, wall thickness, the depth of the bone-facing porous layer, porosity, and the number, volume and location of structural voids. Results The mass varied by up to 13.44 g. The T1 and T2 shells had a median internal roughness of 0.18 μm and 0.43 μm, (p

Abstract Background Accurate diagnosis and treatment of complex cardiac tumors poses challenges, particularly when surgical resection is considered. 3D reconstruction and printing appear as a novel approach to allow heart teams for optimal surgical and post operative care. Methods We report two patients with uncommon masses including a cardiac angiosarcoma (CAS) and a IgG4-related disease (IgG4-RD) with exclusive cardiac involvement. In both cases, three-dimensional (3D) reconstruction and 3D-printed models were utilized to aid the surgical team achieve optimal pre-operative planning. Both patients underwent ECG-gated cardiac computed tomography angiography (CCTA) imaging and, due to the complex anatomy of the masses, their large dimensions, proximity to vital cardiac and vascular structures, and unclear etiology, computational and 3D-printed models were created for surgical planning. An exploratory literature review of studies using 3D-printed models in surgical planning was performed. Results In case 1 (CAS), due to the size and extension of the mass to the right ventricular free wall, surgical intervention was not considered curative and, during thoracotomy, an open biopsy confirmed the imaging suspicion of CAS which guided the initiation of optimal medical treatment with chemotherapy and, after clear tumor retraction, the patient underwent a second surgical intervention, and during the 18 months of follow-up showed no signs of recurrence. In Case 2 (IgG4-RD), the patient underwent uncomplicated total surgical resection; this allowed directed treatment and, at 12 months follow-up, there are no signs of recurrence. Computational and 3D-printed models were used to plan the surgery and to confirm the findings. Limited studies have explored the use of 3D printing in the surgical planning of tumors. Conclusions We present two patients with uncommon cardiac tumors, highlighting the significant value of 3D models in the anatomical characterization and assessment of their extension. These models may be essential in surgical planning for complex cardiovascular cases and could provide more information than conventional imaging modalities. Further studies are needed to demonstrate the impact of 3D technologies in studying cardiac tumors.

Three-dimensional printing is a rapidly growing manufacturing method for orthopaedic implants and it is currently thriving in several other engineering industries. It enables the variation of implant design and the construction of complex structures which can be exploited in orthopaedics and other medical sectors. In this review, we develop the vocabulary to characterise 3D printing in orthopaedics from terms defined by industries employing 3D printing, and by fully examining a 3D-printed off-the-shelf acetabular cup (Fig. 1). This is a commonly used 3D-printed implant in orthopaedics, and it exhibits a range of prominent features brought about by 3D printing. The key features and defects of the porous and dense regions of the implant are clarified and discussed in depth to determine reliable definitions and a common understanding of characteristics of 3D printing between engineers and medical experts in orthopaedics. Despite the extensive list of terminology derived here, it is clear significant gaps exist in the knowledge of this field. Therefore, it is necessary for continued investigations of unused implants, but perhaps more significantly, examining those in vivo and retrieved to understand their long-term impact on patients and the effects of certain features (e.g. surface-adhered particles). Analyses of this kind will establish an understanding of 3D printing in orthopaedics and additionally it will help to update the regulatory approach to this new technology.

The main task of this work is the optimization of the manufacturing process of Al-alloy lattice cellular structures with rhombic cell, obtained with lost-PLA technique. It is an easy, environment sustainable and economical technique (both for infrastructure and operating costs) for the manufacturing of Al porous structure based on the 3D printing of PLA and replication process alternative to that based on expensive metal 3D printers. Plaster processing, PLA burnout and AA 6082 alloy casting conditions and parameters have been suitably tuned in order to get final samples with geometry and surface finishing conditions identical to the starting ones made in PLA. A good replication process has been implemented with a high repeatability rate and accurate surface finishing, comparable with that of the PLA printed objects. Morphological analysis on PLA and Al 6082 was conducted as well microstructural analysis and Vickers microhardness tests on Al alloy samples in the as-cast conditions. Metallography reveals the presence of AlFeSi and AlFeMnSi intermetallic phases at the cell boundaries and some coarse precipitates Mg2Si in the AA 6082 alloy. Microstructures and HV measured values are aligned with literature data for this alloy in the same (as-cast) conditions.

In this study, we used the three-dimensional (3D) printing method to design and fabricate a radar-absorbing structure (RAS) to protect against damage caused by lightning strikes. A carbon black-dispersed 3D filament was used as reinforcement in the composite, and metalized fibers served as the feedstock for 3D-printing. The return losses measured in the X-band and Ku-band (8.2–18 GHz) indicated a maximum return loss of −28.98 dB at 10.68 GHz, with a broad bandwidth of 6.56 GHz in the frequency range of 8.2-18 GHz. A coupled electrical–thermal analysis confirmed that the proposed carbon black-dispersed filament provided conductive paths, which contributed to direct current, energy dissipation, and lightning strike protection. The 3D-printing method ensured a sufficient level of electrical conductivity, limiting the area and depth of damage caused by lightning strikes. Therefore, 3D-printed-RASs, reinforced by electrically conductive materials, can effectively protect against lightning strikes. [ABSTRACT FROM AUTHOR]

Introduction: In recent years, three-dimensional (3D) printing has emerged as a new manufacturing technique for orthoses, showing comparable stability and wearing comfort to traditional orthoses. However, the lengthy designing and printing process is assumed to take more time than the common practice of manufacturing low-temperature thermoplastic orthoses (LTTOs). The aim of this prospective cross-sectional study was to compare the production time of 3D-printed orthoses (3DPO) to LTTOs. Methods: The active and passive time needed to manufacture the orthoses was measured in a clinical setting. 17 orthoses (8 3DPOs and 9 LTTOs) were included in the data analysis. Results: The mean total production time of a 3DPO (12:14:50h total time; 0:44:35h active production time) was significantly longer than in LTTOs (0:14:14h; p < 0.001). Discussion: The longer production time might be a hurdle regarding the implementation of 3DPOs in hand therapy. Although 3D-printing might become more cost- and time-efficient due to future developments in technology and growing experience, some practical advantages of LTTOs prevail, such as the fast and efficient provision of orthoses and the adaptability of the material if subsequent changes are needed. A combination of both manufacturing techniques may be a feasible solution to provide patient-centred orthosis provision in future hand therapy practice. [ABSTRACT FROM AUTHOR]

Breast cancer ranks as the second most common cause of mortality among women globally, with the potential to increase survival rates by 97% through early detection. This study focuses on developing an innovative triple-band microstrip patch antenna designed to operate within the 2–6 GHz frequency spectrum. Simulation tests were conducted to evaluate its efficacy in early breast cancer detection. The antenna, constructed from copper tape and five different substrates (Felt, FR4, PET, PLA, TPU), was chosen considering its advantages for various applications. This design prioritizes wearer comfort while ensuring functionality and allows for producing antenna structures in desired geometries using 3D printing, even in complex configurations. With a general size of 30 × 30 mm2, the antenna underwent analyses on tumor-free models with tumors of different shapes and sizes, and additionally, to evaluate the performance of multiple antennas in detecting cancers, tumor models with 2 and 3 antenna numbers were analyzed in a total of six different breast scenarios. Critical performance parameters such as specific absorption rate (SAR), return loss (S11), and voltage standing wave ratio (VSWR) were obtained for each generated model. Simulation outcomes indicated SAR values within the permissible threshold for medical applications. Moreover, VSWR values maintained acceptability, while variations in return losses were contingent upon tumor dimensions, location, and the number of antennas used. Furthermore, the antenna’s adaptability to bending was scrutinized through bending analyses, affirming its robustness, and sustained operational capability. One of the significant contributions of the study is the utilization of recyclable filaments such as PLA, TPU, and Protopasta in experimental investigations, providing a pathway for producing environmentally friendly and flexible antennas and breast phantoms. This study offers a way to develop more sensitive and reliable breast cancer screening and early diagnosis tools. [ABSTRACT FROM AUTHOR]

Highlights Challenges and future directions for 3D-printed metal-organic frameworks (MOFs) monoliths in environmental applications are discussed. Various strategies for fabrication of 3D-printed MOF monoliths are summarized. Advancements in 3D printing enable customizable and high-performance MOF monoliths. 3D orienting of MOFs opens avenues for applications in water treatment and gas adsorption.

Facile and rapid 3D fabrication of strong, bioactive materials can address challenges that impede repair of large-to-massive rotator cuff tears including personalized grafts, limited mechanical support, and inadequate tissue regeneration. Herein, we developed a facile and rapid methodology that generates visible light-crosslinkable polythiourethane (PHT) pre-polymer resin (∼30 min at room temperature), yielding 3D-printable scaffolds with tendon-like mechanical attributes capable of delivering tenogenic bioactive factors. Ex vivo characterization confirmed successful fabrication, robust human supraspinatus tendon (SST)-like tensile properties (strength: 23 MPa, modulus: 459 MPa, at least 10,000 physiological loading cycles without failure), excellent suture retention (8.62-fold lower than acellular dermal matrix (ADM)-based clinical graft), slow degradation, and controlled release of fibroblast growth factor-2 (FGF-2) and transforming growth factor-β3 (TGF-β3). In vitro studies showed cytocompatibility and growth factor-mediated tenogenic-like differentiation of mesenchymal stem cells. In vivo studies demonstrated biocompatibility (3-week mouse subcutaneous implantation) and ability of growth factor-containing scaffolds to notably regenerate at least 1-cm of tendon with native-like biomechanical attributes as uninjured shoulder (8-week, large-to-massive 1-cm gap rabbit rotator cuff injury). This study demonstrates use of a 3D-printable, strong, and bioactive material to provide mechanical support and pro-regenerative cues for challenging injuries such as large-to-massive rotator cuff tears.

Abstract Extrusion-based bioprinting is an established method in biofabrication. Suitable bioinks have fundamentally different compositions and characteristics, which should be examined, in order to find a perfect model system. Here, we investigate the effect of two alginate-based, yet unalike 3D-printed bioinks, pre-crosslinked alginate-dialdehyde gelatin (ADA-GEL) and a mixture of alginate, hyaluronic acid, and gelatin (Alg/HA/Gel), on the melanoma cell line Mel Im and vice versa in terms of stiffness, shrinkage, cellular behavior and colony formation over 15 days. Rheological stiffness measurements revealed two soft gels with similar storage moduli. The cells did not have a significant impact on the overall stiffness, whereas ADA-GEL (2.5/2.5%) was significantly stiffer than Alg/HA/Gel (0.5/0.1/3%). Regarding the shrinkage of printed constructs, cells had a significant influence, especially in ADA-GEL, which has covalent bonds between the oxidized alginate and gelatin. Multi-photon microscopy exhibited proliferation, cell spreading and migration in ADA-GEL with cell–cell and cell–matrix interaction, dissimilarly to Alg/HA/Gel, in which cells formed spherical, encapsulated colonies. Scanning electron microscopy and histology showed degradation and multi-layered growth on ADA-GEL and fewer examples of escaped cells on Alg/HA/Gel. Both gels serve as proliferation bioink for melanoma with more necrosis in deeper Alg/HA/Gel colonies and differences in spreading and matrix interaction. These findings show the importance of proper characterization of the bioinks for different applications.

Technologies capable of noninvasively sampling different locations in the gut upstream of the colon will enable new insights into the role of organ‐specific microbiomes on human health. Herein, an ingestible pill for the sampling of gut lumen based on one of the earliest hydraulic machines known as an Archimedes screw is reported. The design contains twisted wires as Archimedes screw driven by a motor, wirelessly activated using a magnet. The sampling performance of the screw‐pump pill is characterized using realistic in vitro models and validated in vitro using E. coli expressing different fluorescent proteins. The use of the Archimedes screw enables the pill to sample the dense GI environment. The pill is also tested ex vivo in the pig intestine and in vivo in pigs. Herein, the results show that the bacterial populations recovered from the pill's chamber closely resemble the targeted bacterial population of the microenvironment to which the pill is exposed. Such ingestible devices have the potential to revolutionize the understanding of the spatial diversity of the gut microbiome and its response to medical conditions and treatments. [ABSTRACT FROM AUTHOR]

Highlights: Challenges and future directions for 3D-printed metal-organic frameworks (MOFs) monoliths in environmental applications are discussed. Various strategies for fabrication of 3D-printed MOF monoliths are summarized. Advancements in 3D printing enable customizable and high-performance MOF monoliths. 3D orienting of MOFs opens avenues for applications in water treatment and gas adsorption. Metal–organic frameworks (MOFs) have been extensively considered as one of the most promising types of porous and crystalline organic–inorganic materials, thanks to their large specific surface area, high porosity, tailorable structures and compositions, diverse functionalities, and well-controlled pore/size distribution. However, most developed MOFs are in powder forms, which still have some technical challenges, including abrasion, dustiness, low packing densities, clogging, mass/heat transfer limitation, environmental pollution, and mechanical instability during the packing process, that restrict their applicability in industrial applications. Therefore, in recent years, attention has focused on techniques to convert MOF powders into macroscopic materials like beads, membranes, monoliths, gel/sponges, and nanofibers to overcome these challenges.Three-dimensional (3D) printing technology has achieved much interest because it can produce many high-resolution macroscopic frameworks with complex shapes and geometries from digital models. Therefore, this review summarizes the combination of different 3D printing strategies with MOFs and MOF-based materials for fabricating 3D-printed MOF monoliths and their environmental applications, emphasizing water treatment and gas adsorption/separation applications. Herein, the various strategies for the fabrication of 3D-printed MOF monoliths, such as direct ink writing, seed-assisted in-situ growth, coordination replication from solid precursors, matrix incorporation, selective laser sintering, and digital light processing, are described with the relevant examples. Finally, future directions and challenges of 3D-printed MOF monoliths are also presented to better plan future trajectories in the shaping of MOF materials with improved control over the structure, composition, and textural properties of 3D-printed MOF monoliths. [ABSTRACT FROM AUTHOR]

The development of a general‐purpose machine learning algorithm capable of quickly identifying optimal 3D‐printing settings can save manufacturing time and cost, reduce labor intensity, and improve the quality of 3D‐printed objects. Existing methods have limitations which focus on overall performance or one specific aspect of 3D‐printing quality. Here, for addressing the limitations, a multi‐objective Bayesian Optimization (BO) approach which uses a general‐purpose algorithm to optimize the black‐box functions is demonstrated and identifies the optimal input parameters of direct ink writing for 3D‐printing different presurgical organ models with intricate geometry. The BO approach enhances the 3D‐printing efficiency to achieve the best possible printed object quality while simultaneously addressing the inherent trade‐offs from the process of pursuing ideal outcomes relevant to requirements from practitioners. The BO approach also enables us to effectively explore 3D‐printing inputs inclusive of layer height, nozzle travel speed, and dispensing pressure, as well as visualize the trade‐offs between each set of 3D‐printing inputs in terms of the output objectives which consist of time, porosity, and geometry precisions through the Pareto front. [ABSTRACT FROM AUTHOR]

Modern human societies are highly dependent on plastic materials, however, the bulk of them are non‐renewable commodity plastics that cause pollution problems and consume large amounts of energy for their thermal processing activities. In this article, a sustainable cellulose hydroplastic material and its composites, that can be shaped repeatedly into various 2D/3D geometries using just water are introduced. In the wet state, their high flexibility and ductility make it conducive for the shaping to take place. In the ambient environment, the wet hydroplastic transits spontaneously into rigid materials with its intended shape in a short time of <30 min despite a thickness of hundreds of microns. They also possess humidity resistance and are structurally stable in highly humid environments. Given their excellent mechanical properties, geometry reprogrammability, bio‐based, and biodegradable nature, cellulose hydroplastic poses as a sustainable alternative to traditional plastic materials and even "green" thermoplastics. This article also demonstrates the possibility of 3D‐printing these hydroplastics and the potential of employing them in electronics applications. The demonstrated hydroshapable structural electronic components show capability in performing electronic functions, load‐bearing ability and geometry versatility, which are attractive features for lightweight, customizable and geometry‐unique electronic devices. [ABSTRACT FROM AUTHOR]

Background: In water calorimetry, absolute dose to water is determined by measuring radiation‐induced temperature rises. In conventional water calorimeters, temperature detectors are housed in handmade glass vessels that are filled with high‐purity water, thus mitigating radiation‐induced exo/endothermic chemical reactions of impurities that would otherwise introduce additional heat gain/loss, known as heat defect. Being hand‐crafted, these glass vessels may suffer from imperfections, have shape and design constraints, are often backordered, and can be prohibitively expensive. Purpose: The purpose of this work is to determine suitability of 3D‐printed plastic vessels that are further coated for use in water calorimetry applications, and to study their stability and characterize their associated heat defect correction factor (khd)${k_{{\mathrm{hd}}}})$. This novel vessel production technique would allow for cost‐effective rapid construction of vessels that can be produced with high accuracy and designs that are simply not practical with current glass vessel construction techniques. This in turn enables water calorimetry applications in many novel radiation delivery modalities, which may include spherical vessels in GammaKnife ICON water calorimetry as an example. Methods: Eight vessels were 3D‐printed using Accura ClearVue in an SLA 3D‐printer. Two vessels were coated with Parylene C and four were coated with Parylene N. The water calorimetry preparation procedures followed for these vessels was identical to that of our traditional glass‐vessels (i.e., same cleaning procedures, same high purity water, and same saturation procedures with high purity hydrogen gas). The performance of each vessel was characterized using our in‐house built water calorimeter in an Elekta Versa using both 6 MV flattening filter‐free (FFF) and 18 MV beams. The stability of the coating as function of time and accumulated dose was evaluated through repeated measurements. khd${k_{{\mathrm{hd}}}}\;$ of each vessel was determined through cross‐comparisons against an Exradin A1SL ionization chamber with direction calibration link to Canada's primary standard laboratory. Results: kHD${k_{{\mathrm{HD}}}}\;$ of the two uncoated vessels differed by 2.8% under a 6 MV FFF beam. Vessels coated with Parylenes resulted in a stable and reproducible heat defect for both energies. An overall khd${k_{{\mathrm{hd}}}}$ of 1.001 ± 0.010 and 1.005 ± 0.010 were obtained for Parylene N and Parylene C coated vessels respectively. All Parylene coated vessels showed agreement, within the established uncertainties, to the zero‐heat defect observed in a hydrogen‐saturated glass vessel system. An additional long‐term study (17 days) of a Parylene N vessel showed no change in response with accumulated dose and time. Electron microscopy images of a Parylene N coated vessel showed a uniform intact coating after repeated irradiations. Conclusions: An uncoated 3D‐printed vessel is not viable for water calorimetry because it exhibits an unstable vessel‐dependent heat defect. However, applying a Parylene coating stabilizes the heat defect, suggesting that coated 3D‐printed vessels may be suitable for use in water calorimetry. This method facilitates the creation of intricate vessel shapes, which can be efficiently manufactured using 3D printing. [ABSTRACT FROM AUTHOR]

Objectives: To assess the feasibility of producing 3D‐printed intracoronal restorations, thin and ultrathin veneers, and to compare their mechanical behavior, accuracy, biological, and stain susceptibility to the currently applied milled restorations. Materials and Methods: The databases were comprehensively searched for relevant records up to January 2024 without language restrictions. All studies that assessed 3D‐printed partial coverage restorations including inlays, onlays, laminate, and occlusal veneers were retrieved. Results: The web search yielded a total of 1142 records, with 8 additional records added from websites at a later stage. Only 17 records were ultimately included in the review. The included records compared 3D‐printed; alumina‐based‐ and zirconia ceramics, lithium disilicate ceramics, polymer infiltrated ceramics, polyetheretherketone (PEEK), resin composites, and acrylic resins to their CNC milled analogs. The pooled data indicated that it is possible to produce ultrathin restorations with a thickness of less than 0.2 mm. 3D‐printed laminate veneers and intracoronal restorations exhibited superior trueness, as well as better marginal and internal fit compared to milled restorations (p < 0.05). However, it should be noted that the choice of materials and preparation design may influence these outcomes. In terms of cost, the initial investment and production expenses associated with 3D printing were significantly lower than those of CNC milling technology. Additionally, 3D printing was also shown to be more time‐efficient. Conclusions: Using additive manufacturing technology to produce restorations with a thickness ranging from 0.1 to 0.2 mm is indeed feasible. The high accuracy of these restorations, contributes to their ability to resist caries progression, surpassing the minimum clinical threshold load of failure by a significant margin and reliable adhesion. However, before 3D‐printed resin restorations can be widely adopted for clinical applications, further improvements are needed, particularly in terms of reducing their susceptibility to stains. Clinical Significance: 3D‐printed intracoronal restorations and veneers are more time and cost‐efficient, more accurate, and could provide a considerable alternative to the currently applied CNC milling. Some limitations still accompany the resin materials, but this could be overcome by further development of the materials and printing technology. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethane (TPU) has emerged as extremely benign materials for next-generation manufacturing using additive manufacturing processes due to its favorable mechanical properties, durability, and as well as biocompatibility. However, the lack of stiffness of TPU affects its buckling strength and performance efficiency. Therefore, an efficient method of optimization of a 3D-printable composition of TPU-based blends is necessary. In this work, attempts were made to explore material extrusion additive manufacturing technique of acrylonitrile–butadiene–styrene (ABS)/TPU blends with particular reference to mechanical and damping behaviour. Design of experiment (DoE) was used to determine the optimum printing parameters. Rheological studies were exploited to understand the printability, and optimum 3D-printable blend composition. The damping behaviour of each blend composition was calculated and a damping ratio (ξ) between 1 ≤ ξ ≤ 2 was observed for 40 wt% ABS loading, which raised to 1 ≤ ξ ≤ 4 for 80 wt% ABS loaded blend specimen. Furthermore, for ABS incorporated TPU, a significant enhancement of stiffness over neat TPU was achieved, thereby reasonably addressing the filament stiffness issue. This work introduces an efficient method of improving TPU filament printability while parallelly identifying the printable blend composition which can be beneficial for several potential applications. [ABSTRACT FROM AUTHOR]