3D Printing Research Articles

Assessment of Physio-Mechanical characteristics of ABS/PETG blended parts fabricated by Material Extrusion 3D printing

Assessment of Physio-Mechanical characteristics of ABS/PETG blended parts fabricated by Material Extrusion 3D printing

Extracellular matrix mimetic supramolecular hydrogels reinforced with covalent crosslinked mesoporous silica nanoparticles.

The extracellular matrix (ECM) is a dynamic environment that is primarily built up from fibrous proteins (e.g., elastins, fibronectins, collagens, and laminins) and plays a vital role in tissue regeneration processes. Therefore, the development of supramolecular hydrogels that can mimic the ECM's dynamicity and fibrous structure is of great interest in regenerative medicine. However, such hydrogels generally have weak mechanical properties and poor structural stability, which significantly limits their potential applications. To overcome this drawback, we developed a new type of hybrid network composed of supramolecular assemblies with covalent nanoparticle-based crosslinkers. The ECM mimetic hydrogels were created through UV-initiated thiol-ene crosslinking between norbornene functionalized benzene-1,3,5-tri carboxamide (NBTA) macromonomers and thiol functionalized mesoporous silica nanoparticles (MSN). We hypothesized that the MSN would improve the mechanical properties by crosslinking the NBTA supramolecular fibrous hydrogels. Notably, the covalent incorporation of MSNs did not disrupt the fibrous morphology of the resulting NBTA-MSN nanocomposites. Furthermore, these supramolecular nanocomposites demonstrated higher structural stability and elasticity compared to pristine NBTA hydrogels. Rheology studies showed that the mechanical properties of NBTA-MSN hydrogels could be tuned by adjusting MSN wt%. Interestingly, NBTA-MSN nanocomposites exhibited self-healing and injectability despite the covalent crosslinking of MSNs. In vitro studies confirmed that NBTA-MSN nanocomposites showed good cytocompatibility and maintained the viability of encapsulated MG63 cells. As a proof of concept, we also demonstrated that MSNs could act as ion reservoirs for calcium and phosphate within the hydrogel networks in addition to being covalent crosslinkers. Taken together, our work offers a promising strategy to create hybrid, biomimetic supramolecular nanocomposite materials for various applications such as injectable materials for bone tissue engineering, and reinforced bioinks for 3D printing applications.

Effect of activator dosage and mass ratio of GGBFS to FA on 3D printing performance of kenaf geopolymer

Effect of activator dosage and mass ratio of GGBFS to FA on 3D printing performance of kenaf geopolymer

Advancements in Colloidosome Fabrication, Functionalization, and Applications: A Comprehensive Review

Abstract: Among the recent developments in the field of microcapsules, colloidosomes microcapsules made of colloidal particles have elicited much interest in promising perspectives in microencapsulation technologies. First reported by Dinsmore et al., these structures hold a lot of potential in different areas of application, which include gene delivery, targeting the brain, and tumor treatment. However, the challenges associated with their permeability and stability limit the use of these coatings. Nevertheless, these problems define colloidosomes as possessing some features of protocells that include metabolic activities and response to stimuli, which make them significant in synthetic biology and biomimetic systems. In drug delivery, colloidosomes have the potential of providing solubility, stability, and a controlled rate of drug release, which will have an impact on the therapeutic use of drugs. Fabrication of colloidosomes is done in many ways, and the common ones include the mulsion strategy, layer adsorption, and microfluidics strategy. Some of these fabrication techniques have been investigated in the recent past to determine how their application can lead to enhanced colloidosome characteristics. Some of these methods include spray drying, sol-gel processes, and electrostatic assembly. For example, the study by Payizila Zulipiker et al. showed that different levels of permeability are controllable through the use of spray drying technology. Another study by Jia Jia et al. presented the preparation of pH-responsive colloidosomes and the high efficiency of encapsulation. Consequently, improvements in the manufacturing process and new self-assembly technologies that include microfluidics systems have also improved the creation of colloidosomes. New advancements in the field of colloidosome synthesis, as well as their surface modification, will open up numerous application prospects in the fields of pharmaceutics, regenerative medicine, and bioinspired materials science. New trends range from 3D printing to stimuli-responsive materials and design, as well as hybrid systems that are application- specific. Despite the difficulties that remain to be faced, colloidosomes represent an extraordinary opportunity for the growth of biotechnology and materials science to open the path to new generations of drugs and bioinspired applications.

4D printing of smart scaffolds for bone regeneration: a systematic review.


As a novel emerging technology, four-dimensional (4D) printing allows 3D-printed materials to change over time. This systematic review is conducted to evaluate the purpose, materials, physiomechanical, and biological properties of 4D-printed scaffolds used for bone tissue engineering.
Method and materials:
An electronic search was conducted following the PRISMA 2020 guidelines in PubMed, Scopus, Web of Science, and Google Scholar online databases limited to English articles until April 2024. Studies in which scaffolds were fabricated through 3D printing methods responding to external stimulation were included. The quality of in vitro and in vivo studies was evaluated through the modified CONSORT checklist and SYRCLE's risk of bias tool.
Results:
The full text of 57 studies were reviewed, and 15 studies met the inclusion criteria. According to the analyzed studies, most scaffolds responded to temperature changes showing shape memory effect. Polyurethane (PU) and poly(lactic acid) (PLA) were the most common shape memory polymers, and the most common fabrication method used was Fused Deposition Modeling (FDM).
Conclusion:
A comprehensive systematic review of the studies from the past 10 years demonstrated several findings: 1) Shape memory, drug delivery, and shape morphing are three general purposes of 4D printing for bone regeneration. 2) Smart materials used for 4D printing mostly consist of shape memory polymers. 3) Temperature changes account for the majority of stimulation used for 4D printing. 4) incorporating 4D printing principles does not have a negative impact on the physiomechanical properties of the designed scaffold. 5) The 4D-printed scaffolds show a higher osteogenic differentiation capacity than their identical 3D-printed structures in terms of bone regeneration.&#xD.

Comparison of the safety of flexible ureteroscopy with the different irrigation methods in a 3D print kidney model.

To compare intrarenal pressure (IRP) and irrigation flow by varying suspended water heights and hand-held pressure pumping during flexible ureteroscopy using an in vitro 3D printed kidney model. A 3D-printed silicone model was used to simulate the kidney. The ureteral access sheath(UAS) was connected to the kidney model and positioned at the ureteropelvic junction. Central venous pressure tubing was used to monitor the pressure in the renal pelvis under different conditions. Sheath sizes of 12Fr and 14Fr were tested with flexible ureteroscope (fURS) sizes of 7.5, 8.5, and 9.5Fr, respectively. The irrigation was gravity-based, with suspended water heights set at 60, 90, 120, 150, and 180cm. The manual pumping as another set of measurement is used to measure the maximum intrarenal pressure. Using a 12Fr sheath with a 9.5Fr fURS loading without additional accessories resulted in IRP ranging from 8.4 to 17.5 cmH2O, while manual pumping perfusion pressure exceeded 60 cmH2O. Loading a 200-um laser fiber reduced the pressure to 6.4-10.5 cmH2O, and using a stone basket decreased it to 4.0-5.0 cmH2O. Using a 14Fr sheath with a 9.5Fr fURS resulted in an IRP of 2.5-6.0 cmH2O, compared to 17 cmH2O with manual pumping. With a 12Fr sheath and a 7.5Fr fURS, the IRP ranged from 5.4 to 8.2 cmH2O, while manual pumping resulted in 25.5 cmH2O. With a 14Fr sheath and a 7.5Fr fURS, the IRP ranged from 1.5 to 4.3 cmH2O, and manual pumping resulted in 9.0 cmH2O. When using a UAS in a flexible ureteroscopy, the IRP can be maintained within a safe range with different fURS/UAS combos with a suspended water height of less than 180cm. However, with specific fURS/UAS(9.5Fr/12Fr) combos, the IRP exceeded the safe limit when using manual pumping. Gravity irrigation with a suspended water height of less than 180cm is safe in this simulated clinical environment.

Polysaccharides and Composite Adsorbents in the Spotlight for Effective Agrochemical Residue Removal from Water

Agrochemical residues, including pesticides and herbicides, pose significant environmental and health risks when present in water sources. Conventional water treatment methods often fall short in effectively removing these persistent pollutants, necessitating innovative solutions. This review explores the use of polysaccharides and composite adsorbents as sustainable alternatives for agrochemical residue removal from water. Biopolymers such as chitosan, alginate, and cellulose are highlighted for their biodegradability, biocompatibility, and ability to be functionalized for enhanced adsorption performance. Recent advances in the development of composite materials incorporating nanomaterials, such as graphene, oxide, and metal oxides, have shown significant promise in enhancing the efficiency and selectivity of agrochemical adsorption. The review also addresses the fundamental mechanism of adsorption, such as electrostatic interactions, hydrogen bonding, and hydrophobic forces, that contribute to the effectiveness of these materials. Challenges associated with scalability, regeneration, and real-world applications are discussed, as well as future opportunities for integrating emerging technologies like 3D printing and machine learning into adsorbent design. Overall, polysaccharides and composites offer a promising pathway toward achieving efficient and sustainable agrochemical residue removal, with ongoing research needed to overcome current limitations and optimize their practical application in water treatment.

Three-dimensional finite element analysis of occlusal stress on maxillary first molars with different marginal morphologies restored with occlusal veneers

BackgroundThere are differences in the research results regarding which edge design of occlusal veneers can achieve the best long-term success rate as a relatively new fixed prosthesis restoration method. Further research is needed. The three-dimensional finite element method was used to conduct stress analysis on occlusal veneers of maxillary first permanent molars with different thicknesses and margin preparation designs. The aim of this study was to provide mechanical research evidence and a reference for exploring standardized clinical protocols for the design of occlusal veneer restorations of maxillary first molars.MethodA 3Shape (Intraoral Scanner) was used to scan the maxillary first molar teeth in vitro, after which 3D printing was carried out. Three different edge designs were applied to identical teeth: straight-beveled finishing line(SFL), chamfer finishing line(CFL), and standard cuspal inclination(SCI). Preparation was carried out with a thickness of 0.5 mm. Using the surface deformation feature, the occlusal veneer was thickened to 0.5 mm and 1.0 mm, and periodontal ligaments were added. They were then placed into the upper and lower jaws and dental arches. Finite element analysis was performed after applying bite force dispersion to the loading area on the mandible following dynamic contact.Results(1) As the thickness increased, the maximum Von Mises stress in the occlusal veneers SFL and CFL also increased, while the SCI exhibited the opposite trend. (2). The trend of the maximum Von Mises stress in the adhesive layer decrease gradually with increasing thickness of the occlusal veneer. The stresses of the SFL and CFL is concentrated primarily at the edge position below the functional cusp, resulting in relatively low adhesive stress. However, in the SCI group, the maximum stress at the edge of the adhesive layer exceeds the maximum shear strength of commonly used adhesives.ConclusionsUnder the experimental conditions, the mechanical properties of the maximum Von Mises stress in the SFL, CFL, and SCI occlusal veneers meet clinical needs. Incorporating the minimally invasive concept of tooth preservation, a thickness of 1.0 mm are optimal for glass ceramic occlusal veneers on maxillary first molars.

Crystal Transduction 3D Printing of Bio‐Hydrogels with High Fidelity and Order Micro Pores

Abstract3D printing of bio‐hydrogel scaffolds are widely used in tissue regeneration. However, due to the ultra‐soft properties of bio‐hydrogels, it is hard to print them precisely. Here, crystal transduction 3D printing with high fidelity is proposed to address this challenge. A phase‐transition bio‐inks system with beeswax is developed for crystal transduction, which can accelerate energy consumption and induce soft bio‐inks to quickly harden during printing. Interestingly, an interconnected porous hydrogel scaffold can be obtained after washing the crystal beeswax. The porous hydrogel scaffold demonstrated excellent biocompatibility and cell proliferation effect in vitro and is free from defense responses and immunogenicity in vivo. Muscle analog porous scaffolds constructed by high‐fidelity 3D printing significantly improve the tissue function recovery of rats with muscle defects, compared with the conventional printed hydrogel with a non‐matched shape. These structure‐performance design rules create exciting opportunities to customize 3D‐printed porous hydrogel scaffolds with high fidelity.

Enhanced detection of surface deformations in LPBF using deep convolutional neural networks and transfer learning from a porosity model

Our previous research papers have shown the potential of deep-learning models for real-time detection and control of porosity defects in 3D printing, specifically in the laser powder bed fusion (LPBF) process. Extending these models to identify other defects like surface deformation poses a challenge due to the scarcity of available data. This study introduces the use of Transfer Learning (TL) to train models on limited data for high accuracy in detecting surface deformations, marking the first attempt to apply a model trained on one defect type to another. Our approach demonstrates the power of transfer learning in adapting a model known for porosity detection in LPBF to identify surface deformations with high accuracy (94%), matching the performance of the best existing models but with significantly less complexity. This results in faster training and evaluation, ideal for real-time systems with limited computing capabilities. We further employed Gradient-weighted Class Activation Mapping (Grad-CAM) to visualize the model’s decision-making, highlighting the areas influencing defect detection. This step is vital for developing a trustworthy model, showcasing the effectiveness of our approach in broadening the model’s applicability while ensuring reliability and efficiency.

Research on frozen sand mold casting technology for complex thin-walled aluminum alloy castings

With the growing emphasis on environmental sustainability and the modernization of the manufacturing sector, the pursuit of eco-friendly practices within the foundry industry has become a critical objective. This paper proposes an innovative solution for environmentally friendly casting: the digital frozen sand mold casting technology. To evaluate its effectiveness, this study analyzed complex thin-walled grid rudder aluminum alloy castings. A comparative analysis was conducted between the binder jetting 3D printing and frozen sand mold (sand mold milling) casting processes. By utilizing Anycasting software, the research explored the filling and solidification processes of ZL101 grid rudder castings under varying mold conditions, aiming to predict the distribution and severity of shrinkage defects. Validation of this approach indicated a machining error of ±0.25 mm for frozen sand molds. The dimensional accuracy of the grid rudder castings achieved a casting tolerance grade of 9 (CT9), and the direct recovery rate of used sand exceeded 98 %, thus positioning this method as a viable alternative to 3D-printed resin sand. Additionally, the study assessed the economic feasibility of frozen sand mold casting technology in terms of resource consumption and production efficiency. The research findings hold significant relevance, offering valuable insights and guidance for traditional casting enterprises seeking to adopt sustainable development practices through the application of leveraging frozen sand casting technology.

Two-step fabrication of clear view SLA millifluidic device for long-term in-vitro cultures

Purpose In vitro millifluidic cultures with perfusion are essential tools to analyse and understand the interactions between cells, their matrix and multi-cell populations. The purpose of this paper is to focus on the design and development of a 3D-printed template that can be used for fabrication of a clear view poly (dimethyl siloxane) (PDMS) device. The major objective is to obtain a transparent device prototype that allows perfusion culture of two cell types for multiple days that can be imaged using laser scanning confocal microscopy. Design/methodology/approach The authors used a two-step approach for achieving the final geometric structure at a faster timeline and lower cost. The first part focuses on comparing the fidelity of the printing templates using fused deposition modelling (FDM) and stereolithography (SLA) printers for a range of dimensions. They then show that the complex geometry chip with connection chambers can be printed using low resolution low cost FormLab SLA printer. The final optimized design was then printed using high-resolution Projet 6000 SLA printer to obtain smoother structures. Findings In this work, the authors have shown that the FormLab SLA printer yields significantly lower error for printing complex design geometries as compared to FDM printer. Result shows that FormLab printer can be used to achieve a minimum dimension of 0.5 mm. They then use the printer to optimize the device dimension for the culture chip which requires several iterations of printing and experimenting. They showed the two-step protocol of printing the optimized template in a high-resolution SLA printer and further fabricating a clear view millifluidic PDMS device that is compatible confocal microscopy imaging. They used this culture chip for perfusion culture of two cell type, and the controlled fluidic exchange between the two chambers led to the formation of neuroglia junction. Originality/value One of the major bottlenecks for obtaining complex geometry in mili/microfluidic device by 3D printing is the need of multiple iterations on printing. This makes the tuning of dimension significantly expensive. Another challenge is to obtain a smooth surface of PDMS that leads to a leak proof clear view device compatible for laser based confocal imaging. The combination of two printers plays a crucial role for the rapid prototyping of the imaging device with flow control. The proposed approach lowers the cost for prototyping of in vitro culture chip with complex geometries to improve on biological research demanding multi-chamber fluidic device.

Advancing optical transparency in 3D‐printed PLA parts using chemical post‐processing

AbstractFused filament fabrication (FFF) is an increasingly popular three‐dimensional (3D) printing technology known for its ability to produce complex 3D models at a low‐cost using polymer materials. Despite its advantages, the poor surface finish and high layer resolution in FFF‐printed parts have hindered its wider adoption, particularly for applications requiring high transparency. Thus, the current study investigates the transparency evaluation of chemically post‐processed 3D‐printed transparent polylactic acid (PLA) parts, focusing on enhancing optical transparency. Fused Filament Fabrication was employed to produce transparent parts made from PLA filament, which were subsequently treated at various time settings using various solvents, including tetrahydrofuran (THF), chloroform or trichloromethane (TCM), and ethyl acetate (EA). This study examines the impact of chemical post‐processing on the surface roughness, transparency, mechanical properties, and dimensional accuracy of solvent treated parts. It has been found that the THF solvent with 40 s of immersion time resulted in a maximum transmittance of 74.66% and minimum surface roughness of 1.777 μm. Based on this finding a case study was also conducted to apply the findings of the current investigation to a practical application. The findings highlight the potential of chemical‐based post‐processing techniques to improve the optical properties of 3D printed PLA, offering a promising approach for applications in optics, medical devices, and consumer goods requiring transparent components.Highlights Effect of chemical post‐processing on 3D‐printed PLA parts was investigated. Tetrahydrofuran, chloroform, and ethyl acetate were used as solvents. Surface roughness, transparency, hardness, and dimensional accuracy were analyzed. Reported a maximum transmittance of 74.66% and minimum surface roughness of 1.777 μm.

Evaluating the outcomes of three dimensional printing-assisted osteotomy on treating varus knee deformity from old tibial plateau fractures.

This study aimed to evaluate the outcomes of three-dimensional (3D) Printing-Assisted Osteotomy in treating varus knee deformity from old tibial plateau fractures. The study retrospectively analyzed patients with varus deformity induced by old-tibial plateau fractures between January 2019 and June 2023. All patients utilized 3D printed models for surgical planning. The Lysholm Knee Score (LKS), Visual Analog Scale (VAS) and Knee Society Score (KSS) were measured for functional outcomes. Medial Proximal Tibial Angle (MPTA), Joint Line Convergence Angle (JLCA), Mechanical Axis (%MA), Medial Tibial Plateau Depression (MTPD), and Femorotibial Angle (FTA) were measured for radiological outcomes. 15 patients (12 males and 3 females) were included in this study and followed up for 21.9 ± 8.6 (range, 12 to 28) months. Healing of the osteotomy sites were achieved in all patients at 15.8 ± 1.5 (range, 13 to 18) weeks. The knee varus deformities were significantly corrected as reflected by %MA (2.13 ± 13.1°(range, -20 to 22) versus 57.06 ± 9.8°(range, 41 to 70), p < 0.01), FTA (186.7 ± 3.2°(range, 181 to 193) versus 172.3 ± 2.1°(range, 169 to 175), p < 0.01), JLCA (5.8 ± 1.7°(range, 3 to 8) versus 1.3 ± 0.8°(range, 0 to 3), p < 0.01), and MPTA (5.6 ± 1.2°(range, 3 to 8) versus 1.2 ± 1.1°(range, -1 to 3), p < 0.01). Postoperative knee function showed dramatic improvements as reflected by VAS (4.6 ± 1.6 (range, 1 to 7) versus 0.7 ± 0.9 (range, 0 to 2), p < 0.01), KSS (50.1 ± 16.5 (range, 27 to 88) versus 88.5 ± 5.2 (range, 80 to 95), p < 0.01), and LKS (49.5 ± 10.2 (range, 37 to 69) versus 89.2 ± 2.5 (range, 87 to 94), p < 0.01). 3D printing technology provides a valuable tool for understanding deformities and optimizing osteotomy strategies, thereby improving surgical efficacy and treatment outcomes. Its clinical application is highly recommended.

Optimization of Cartesian and polar 3D printer structures using finite element analysis: a comparative study on material selection and design enhancement

Optimization of Cartesian and polar 3D printer structures using finite element analysis: a comparative study on material selection and design enhancement

Rapid preparation and mechanism investigation of covalent organic framework membranes by 3D printing based on electrostatic spraying

Covalent organic framework (COF) has great advantages in the field of membrane separation, but the efficient and convenient preparation of COF membranes is still a challenge. Herein, we propose a novel method with green solvent for the preparation of COF membranes based on electrostatic spraying, which can be successfully prepared within 10 min, forming the TpPa COF with a pore size of 1.8 nm. Molecular dynamics simulations demonstrate that electrostatic spraying enhances the reaction rate by lowering the energy barrier and increasing the movement of reacting monomers. Atomization of the solvent in electrostatic spraying causes the rapid volatilization of the solvent, resulting in supersaturation of the generated TpPa, precipitation and crystallization, and promotes the formation of TpPa COF structure. The optimal COF membrane for the separation of Congo red wastewater is prepared by adjusting the voltage, concentration, and spraying time, with selectivity of Na2SO4 for Congo Red attaining 118 and water permeance reaching 70.2 L m-2 h-1 bar-1. This work not only elaborates the membrane preparation mechanism in the electrostatic spraying process, but also greatly shortens the time of COF membrane preparation compared to the traditional method (2–3 days), which contributes to the possibility for practical application of COF membranes.

A new granule extrusion-based for 3D printing of POE: studying the effect of printing parameters on mechanical properties with “response surface methodology”

A new granule extrusion-based for 3D printing of POE: studying the effect of printing parameters on mechanical properties with “response surface methodology”

Breakthrough and Challenging Application: Mixed Reality-Assisted Intracardiac Surgery

Background: While several studies investigate the utility and clinical value of 3D printing in aiding diagnosis, medical education, preoperative planning, and intraoperative guidance of surgical interventions, there is a scarcity of literature regarding concrete applications of mixed reality in the cardiovascular domain due to its nascent stage of study and expansion. This study goes beyond a mere three-dimensional visualization of the cardiac district, aiming to visualize the intracardiac structures within the scope of preoperative planning for cardiac surgery. Methods: The segmentation of the heart was performed through an open-source and a professional software and by applying different procedures. Each anatomical component of the heart, including the aortic valve, was accurately segmented and a 3D model was built to represent the entire heart. Results: Beyond the three-dimensional visualization of the cardiac region, the intracardiac structures were also segmented. A mixed-reality app was implemented with the possibility of exploding the model, interacting with it, and freely sectioning it with a plane. Conclusions: The proposed segmentation methodology allows a segmentation of the valve and the intracardiac structures. Furthermore, the mixed-reality app has confirmed the potential of this technology in diagnostic and preoperative planning, although some limitations should still be overcome.

Publisher Correction: Frontiers in construction 3D printing: self-monitoring, multi-robot, drone-assisted processes

Publisher Correction: Frontiers in construction 3D printing: self-monitoring, multi-robot, drone-assisted processes

High Efficiency Producing Technology Applied in Metal Optical Lens by 3D Wax Printing Combined with Investment Casting

3D printing technology can easily and quickly produce small batch models and full-size parts, which has obvious and important benefits in shortening development time. Since metals exhibit excellent mechanical strength and high wear resistance, metal additive manufacturing (MAM) is a popular technology for making metal parts. However, metal powders and 3D-printing machines are costly, which increases the difficulty of achieving mass production through MAM. In this study, the 3D wax printing and investment casting (WPIC) approach was developed to manufacture high-quality metal optical lenses with high efficiency and low cost. The manufactured lenses had a diameter of 38.1 mm, two radii of curvature (15 and 90 mm), and a cooling channel. These lenses were manufactured through 3D printing by using wax patterns produced through investment casting. The manufacturing efficiency and machining accuracy of the lenses produced using the proposed method were compared with those of lenses produced through MAM and investment casting. The results indicated that the total costs of manufacturing an optical lens through MAM and investment casting were nine and eight times greater, respectively than that of manufacturing an optical lens through WPIC. In addition, the surface roughness of metal lenses manufactured through WPIC was 45% lower than that of lenses manufactured through MAM. Finally, the time required to manufacture 50 metal lenses was only 15 days when WPIC was used; the corresponding time was 25 days and 6 months when MAM and investment casting were used, respectively. According to the above-mentioned results, the WPIC process has excellent advantages in product manufacturing cost and developing schedule over MAM and traditional methods of investment casting.