3D Printing Research Articles

Highly porous sildenafil loaded polylactic acid/polyvinylpyrrolidone based 3D printed scaffold containing forsterite nanoparticles for craniofacial reconstruction

Tissue engineering has emerged as a promising substitute for traditional tissue repair methods. Nowadays, advancements in 3D printing technology have enabled the fabrication of customized scaffolds to support tissue regeneration. In the present study, a polylactic acid-polyvinylpyrrolidone 3D-printed scaffold containing 10 % forsterite was fabricated. Subsequently, lyophilized fucoidan microstructures loaded with sildenafil were filled the channels of this 3D-printed scaffold. The fabricated scaffold loaded with sildenafil was thoroughly characterized, revealing that 97.46 % of the loaded sildenafil was released in a sustained manner over 28 days. Furthermore, the biocompatibility of MG63 was evaluated through cell viability and adhesion tests. The findings indicated a direct and favorable influence on cell behavior. Based on the chicken chorioallantoic membrane assay, the fabricated scaffold significantly increases angiogenesis due to the sustained release of sildenafil. Moreover, in-vivo studies conducted on a rat model demonstrated that the 3D-printed scaffold was able to stimulate and accelerate the repair of calvarial defects within 8 weeks, and the amount of new bone tissue formation was significantly higher than that of other experimental groups. Based on the comprehensive in-vitro and in-vivo assessments, the scaffold with a macro- and microporous structure combined with the ability to release sildenafil is suggested as a potential candidate for repairing bone tissue, especially in the context of skull defects.

Anatomical variations in 3D imaging: a case report of a dorsal metacarpal artery anomaly

This report presents a novel anatomical variant of the second dorsal metacarpal artery (SDMA). In this unique case, the SDMA abnormally penetrates the second dorsal interosseous muscle (SDIM), dividing into two major branches. A deep dorsal branch of the SDMA (dbSDMA) is located within the SDIM and extends to the distal end of the metacarpal. The other branch forms a perforating branch called the P-SDMA, which anastomoses with the palmar metacarpal artery branch (PMAb) and the deep palmar arch branch (DPAcb) in the deep palmar area. The discovery of this SDMA variant is significant for procedures involving complex hand surgeries such as DMA flaps. Understanding this anatomical variation is crucial for accurate surgical planning and can help avoid potential complications during surgery. To elucidate these unique variations, we employ three-dimensional (3D) imaging techniques, demonstrating the potential of these technologies to advance the visualization of anatomical structures and enhance medical education. 3D imaging also facilitates augmented reality applications and 3D printing. Our findings underscore the possible applications of 3D imaging in medical practice and education, potentially transforming anatomy education and surgical planning.

Impact of Graphene Nanoparticles on DLP-Printed Parts' Mechanical Behavior

Digital Light Processing (DLP) is one of the most promising techniques among the additive manufacturing (AM) technologies for polymer resin. The polymer parts produced through this technique demonstrate a diverse range of characteristics that can be specifically designed for various fields of application. Specific attributes can be attained by utilizing polymer composites composed of multiple materials in numerous ratios. This research delves into evaluating and comparing different properties, including microstructure, surface texture, and mechanical behavior, of resin-based polymer composites fabricated using the DLP 3D printing technology. To achieve this, specimens have been printed using photopolymer resin as the base material, with varying percentages of graphene nanoparticles added to the resin. Tensile tests and particle analysis based on optical microscope images validate that optimizing parameters, especially the energy setting of the printer, significantly impact the printed samples' strength, surface texture, layering, and microstructure. The findings indicate that at a specific percentage of graphene, such as 0.5%, there is an increase in tensile strength by 38.1%, Young’s modulus by 54.7%, and Yield strength by 11.2%, accompanied by an improved surface roughness. A graphene concentration of 0.75% results in diminished tensile strength, yield strength, and Young’s modulus. The significance of fine-tuning printing parameters to achieve desired properties in resin-based polymer composites manufactured via 3D printing is highlighted.

All-aqueous liquid crystal emulsions for 4D laser printing of dual-stimuli response printlets with on-demand remote control of drug release

The combination of responsive materials with 3D printing can lead to functional materials and devices for use in health, biofabrication, and biosensing. Here, we utilized an all-aqueous two-phase system made from chitosan and carrageenan to create all-water emulsion bodies, a groundbreaking group of encapsulated emulsions for possible drug delivery. Specifically, we described the development of an original all-aqueous cholesteric bicontinuous liquid crystal (LC) emulsion, which was accomplished by homogenization of a rod-like cellulose nanocrystal (CNC) with two thermodynamically immiscible, phase-separating carrageenan and chitosan solutions. Stable water-in-water emulsions were effectively prepared by mixing the respective CNC/biopolymer dispersions, showing micrometric CNC/chitosan dispersed droplets and a CNC/carrageenan continuous phase. The LC-based emulsion showed a confined 3D percolating bicontinuous network with cholesteric self-assembly of CNC within the carrageenan phase, while the nanoparticles in the chitosan phase remain isotropic. After laser 3D printing of freeze-dried LC-based emulsion, 3D porous printlets loaded with curcumim were produced with a dual stimuli response toward temperature and redox. The curcumin-loaded 3D printlets exhibited superior thermosensitive properties and maintained a sustained drug release profile, exhibiting much greater on-demand release mode at human body temperature. Notably, the 3D printlets demonstrated a gated response in an aqueous environment, showcasing potential advancements in the realms of supramolecular sensors and drug delivery systems.

Recent Advances in Biomaterial‐Based Scaffolds for Guided Bone Tissue Engineering: Challenges and Future Directions

ABSTRACTBone tissue engineering (BTE) has emerged as a promising approach for the regeneration and repair of bone defects caused by trauma, disease, or aging. This review provides an overview of recent advancements in BTE, with a focus on the development and application of biomaterial‐based scaffolds, including natural (e.g., collagen, chitosan), synthetic (e.g., polylactic acid [PLA], polycaprolactone [PCL]), and composite materials (e.g., hydroxyapatite‐based composites). It discusses their properties, benefits, and limitations. Additionally, this review examines innovative fabrication strategies such as 3D printing, electrospinning, and freeze‐drying, which enhance scaffold customization and performance. This review aims to provide insights into future directions of BTE research and its potential applications in regenerative medicine. Functionalization strategies, including surface modifications, coating, and the incorporation of growth factors and cells, are reviewed for their roles in improving scaffold bioactivity. In vivo and in vitro research have demonstrated the therapeutic promise of these scaffolds, while current clinical trials offer insights into their translational use. Challenges facing the translation of these technologies into clinical practice are also highlighted.

Design of 3D printing superhydrophilic pyramid-shaped porous materials for oil-in-water emulsion separation and visualization of separation mechanism

This study focuses on the design and fabrication of a superhydrophilic pyramid-shaped porous material using high-precision 3D printing technology for effective oil-in-water emulsion separation. The unique pyramid-shaped structure enhances droplet interception, significantly improving separation efficiency. The material’s surface was modified with a self-polymerized dopamine (DA) and polyethyleneimine (PEI) coating, resulting in superhydrophilic and underwater superoleophobicity. This porous material achieved a separation flux of 3098 L/m2h with a separation purity of 99.3 %. Computational Fluid Dynamics (CFD) simulations were employed to visualize the emulsion separation mechanism, providing insights into the dynamic process of droplet behavior within the funnel structure. The material also demonstrated excellent corrosion resistance, maintaining its performance after prolonged exposure to acidic, alkaline, and saline environments. These results suggest that the developed material offers a promising solution for high-efficiency oil–water separation with potential applications in environmental remediation and industrial wastewater treatment.

Optimising 3D printed medications for rare diseases: In-line mass uniformity testing in direct powder extrusion 3D printing

Optimising 3D printed medications for rare diseases: In-line mass uniformity testing in direct powder extrusion 3D printing

3D printing of soft magnetoactive superhydrophobic elastomers for droplet manipulation

Soft responsive surfaces have generated significant interest due to their dynamic control over wetting behaviors through geometrical reorganization in response to external stimuli. Here, magnetoactive elastomeric surfaces are 3D printed using the direct ink writing technology. By designing a “high-wall” structure, superhydrophobic ability is achieved, with water contacting angle of 152° and a sliding angle of 9°. The mechanical softness of the elastomer allows for reversible geometrical changes under magnetic field. This deformation can be precisely controlled by adjusting the strength and position of the magnet, causing the water droplet to move towards the desired location with a speed of 3.33 mm/s. This study introduces a new strategy for achieving lossless transportation of μL-scale nonmagnetic droplets, which holds potential for applications in microfluidics and soft robotics.

Investigations on the fracture mechanisms of Z-shaped fissured rock-like specimens

Complex shapes of cracks exist in natural rock masses, however, present research has simplified it into straight line-shaped fissures. In view of this, three-dimensional (3D) printing is employed to make Z-shaped fissured specimens with different main fissure angle α and secondary fissure angle β. The compress fracture experiments are conducted, and full-field strain distributions during crack propagations are obtained using Digital Image Correlation (DIC) technology. Traditional Smoothed Particle Hydrodynamics (SPH) method is improved to examine damage process as well as fracture mechanisms in Z-shaped fissured specimens. It can be concluded that: Wing Crack (WC), Main Crack (MC), Outer Crack (OC) and Inner Crack (IC) are observed in the experiment. The secondary fissure angle β guides the initiation of MC, while the main fissure angle α guides the initiation of WC. Stress–strain curve of 3D printing samples with Z-shaped fissures shows similar trends to that of real rock, experiencing four typical parts. Numerical results show high similarities with experimental results. We have also discussed the crack initiation mechanisms in various main fissure angle α and secondary fissure angle β in the end, and concluded the stress distribution characters. The findings of this research will offer some references for correct understanding of the crack evolution processes and fracture mechanics of Z-shaped fissured rock masses.

Impact of Porosity and Stiffness of 3D Printed Polycaprolactone Scaffolds on Osteogenic Differentiation of Human Mesenchymal Stromal Cells and Activation of Dendritic Cells.

Despite the potential of extrusion-based printing of thermoplastic polymers in bone tissue engineering, the inherent nonporous stiff nature of the printed filaments may elicit immune responses that influence bone regeneration. In this study, bone scaffolds made of polycaprolactone (PCL) filaments with different internal microporosity and stiffness was 3D-printed. It was achieved by combining three fabrication techniques, salt leaching and 3D printing at either low or high temperatures (LT/HT) with or without nonsolvent induced phase separation (NIPS). Printing PCL at HT resulted in stiff scaffolds (modulus of elasticity (E): 403 ± 19 MPa and strain: 6.6 ± 0.1%), while NIPS-based printing at LT produced less stiff and highly flexible scaffolds (E: 53 ± 10 MPa and strain: 435 ± 105%). Moreover, the introduction of porosity by salt leaching in the printed filaments significantly changed the mechanical properties and degradation rate of the scaffolds. Furthermore, this study aimed to show how these variations influence proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hBMSC) and the maturation and activation of human monocyte-derived dendritic cells (Mo-DC). The cytocompatibility of the printed scaffolds was confirmed by live-dead imaging, metabolic activity measurement, and the continuous proliferation of hBMSC over 14 days. While all scaffolds facilitated the expression of osteogenic markers (RUNX2 and Collagen I) from hBMSC as detected through immunofluorescence staining, the variation in porosity and stiffness notably influenced the early and late mineralization. Furthermore, the flexible LT scaffolds, with porosity induced by NIPS and salt leaching, stimulated Mo-DC to adopt a pro-inflammatory phenotype marked by a significant increase in the expression of IL1B and TNF genes, alongside decreased expression of anti-inflammatory markers, IL10 and TGF1B. Altogether, the results of the current study demonstrate the importance of tailoring porosity and stiffness of PCL scaffolds to direct their biological performance toward a more immune-mediated bone healing process.

Strengthening SiC Ceramic Structural Integrity Made via 3D Printing with Pyrolysis and Precursor Infiltration

Strengthening SiC Ceramic Structural Integrity Made via 3D Printing with Pyrolysis and Precursor Infiltration

Evaluation of Image Segmentation Methods for In Situ Quality Assessment in Additive Manufacturing

Additive manufacturing (AM), or 3D printing, has revolutionized the fabrication of complex parts, but assessing their quality remains a challenge. Quality assessment, especially for the interior part geometry, relies on post-print inspection techniques unsuitable for real-time in situ analysis. Vision-based approaches could be employed to capture images of any layer during fabrication, and then segmentation methods could be used to identify in-layer features in order to establish dimensional conformity and detect defects for in situ evaluation of the overall part quality. This research evaluated five image segmentation methods (simple thresholding, adaptive thresholding, Sobel edge detector, Canny edge detector, and watershed transform) on the same platform for their effectiveness in isolating and identifying features in 3D-printed layers under different contrast conditions for in situ quality assessment. The performance metrics used are accuracy, precision, recall, and the Jaccard index. The experimental set-up is based on an open-frame fused filament fabrication printer augmented with a vision system. The control system software for printing and imaging (acquisition and processing) was custom developed in Python running on a Raspberry Pi. Most of the segmentation methods reliably segmented the external geometry and high-contrast internal features. The simple thresholding, Canny edge detector, and watershed transform methods did not perform well with low-contrast parts and could not reliably segment internal features when the previous layer was visible. The adaptive thresholding and Sobel edge detector methods segmented high- and low-contrast features. However, the segmentation outputs were heavily affected by textural and image noise. The research identified factors affecting the performance and limitations of these segmentation methods and contributing to the broader effort of improving in situ quality assessment in AM, such as automatic dimensional analysis of internal and external features and the overall geometry.

Engineering PLA-MXene nanocomposite with balanced mechanical properties for enhanced shape memory effect

AbstractPoly(lactic acid) (PLA) as shape memory material has gained attention due to its biocompatibility, biodegradability, and ease of processing by 3D printing. PLA’s environmentally friendly nature makes it an attractive candidate for sustainable and recyclable shape memory applications. However, PLA’s slow shape recovery rate and low shape fixation percentage hinder its applicability as shape memory material. In the present study, we report MXene-modified PLA (PLA/Mx) nanocomposite with enhanced shape memory effect. Solution processing methods mediated the loading of the MXene in the PLA matrix. Different samples were prepared by varying the weight% of the MXene in the PLA matrix. The structure and morphology of samples were analyzed by XRD and TEM characterization. Thermogravimetric analysis was performed to measure the thermal stability of the composite. Compared with pure PLA, with MXene loading, the PLA/Mx composites show an increase in thermal. The shape recovery study on PLA/Mx samples used temperature as an external stimulus. The PLA/Mx composite exhibited a significantly improved shape memory effect than the PLA alone. The study exhibits that a shape memory effect can be improved by tuning the MXene additive loading in the PLA matrix. The material shape recovery effect was validated by fabricating the spiral structure. The fast shape recovery time 3s and shape fixation/recovery of > 95% was observed for 1 wt% of PLA/Mx. The PLA/Mx composite is expected to contribute significantly to implementing innovative shape memory applications, particularly in the biomedical field for sutures, controlled drug release, and minimally invasive devices.

Reproducing hydrodynamics and elastic objects: A hybrid mesh-free model framework for dynamic multi-phase flows

Reproducing Hydrodynamics and Elastic Objects (RHEO) is a new meshfree modeling framework for simulating complex multi-phase flows of fluids and solids. RHEO is implemented within the open-source Large-Scale Atomic/Molecular Massively Parallel Simulator particle dynamics code and couples a reproducing kernel smoothed particle hydrodynamics scheme for modeling fluid flow and heat transfer with a bonded particle model for modeling breakable elastic bodies. The resulting scheme provides a robust framework for simulating multi-phase material systems with complex and evolving boundaries and interfaces. RHEO collects many advanced mesh-free modeling features into a centralized, modular, and easily extensible package, including heat transport, reversible melting and solidification, particle distribution regularization, and user adjustable kernel accuracy. We report comprehensive tests of RHEO's accuracy and convergence for common benchmark flows of bulk fluids, boundary driven flows, and complex fluid/solid systems. A series of multi-phase systems are highlighted, including a bouncing water balloon, the fracture and flow of a brittle egg, melting of a free-standing solid beam, and conductive cooling and solidification of an extruded polymer during 3D printing.

Microstructure and material properties of 3D-printed bimetallic steels

Corroded steel components can be repaired by laser 3D printing technology. However, studies on the mechanical behaviour of repaired areas composed of a substrate and deposited material are still limited. In this study, 316L stainless steel powder was deposited on Q355B steel plates through 3D laser printing technology to form bimetallic steel plates. Uniaxial tensile tests were conducted on Q355B steel coupons, laser 3D-printed 316L stainless steel coupons, and bimetallic steel coupons. The test results revealed that ductile fracture occurred in the bimetallic steel coupons. The mechanical properties of bimetallic steel are considerably correlated with the properties of the cladding layer and substrate. During the loading process, the axial strain of the bimetallic steel coupons was uniformly distributed along the thickness direction, indicating that the substrate and cladding materials maintained excellent cooperative deformation. Bending tests and scanning electron microscopy observations indicate that a reliable and robust metallurgical bond is established at the interface between the substrate and the cladding layer. The interface area can be divided into the cladding layer, the carburising zone, the decarburised zone, and the Q355B substrate. The microhardness results indicate a considerable increase in the hardness of the carburised layer, which enhances the tensile strength of the bimetallic steel. On the basis of the experimental results, a three-stage model for predicting the stress‒strain curve of bimetallic steel was established.

Preparation of UV curable acrylamide modified epoxy resin and performance in 3D printing

A novel UV-curable 3D printing resin was synthesized by combining diglycidyl ether of bisphenol A (DGEBA) and acrylamide (AAM) to create a UV-curable acrylamide-modified epoxy resin prepolymer. This prepolymer was then uniformly mixed with the photoinitiator TPO and the reactive diluent hydroxyethyl methacrylate (HEMA). By adjusting the prepolymer content, UV-curable 3D printing resins were formulated with prepolymer concentrations of 30 wt%, 40 wt%, and 50 wt%, respectively. Infrared spectroscopy and nuclear magnetic resonance studies indicated that the amino groups in acrylamide reacted with the epoxy groups. When the prepolymer was added at concentrations of 30 wt% and 40 wt%, the viscosity met the requirements for UV-curable 3D printing. Upon completion of curing, these three distinct resins exhibited high mechanical strength, with tensile strength reaching up to 59.42 MPa and flexural strength peaking at 72.25 MPa. The elongation at break ranged from 2.60 % to 4.91 %. Scanning electron microscopy was used to examine the UV-cured 3D printed samples, and comparison with the design files revealed that the printed samples exhibited excellent dimensional stability. The study results indicated that this novel UV-curable epoxy vinyl resin formulation possessed excellent mechanical properties, suitable curing characteristics, and high resolution, making it a highly promising prepolymer for UV-curable 3D printing.

A Patient-Specific 3D Printed Lingual Nerve Protector in Third Molar Extraction.

We present a novel, patient-specific 3D-printed lingual nerve protector designed to minimize the risk of nerve injury during mandibular third molar extraction, a common cause of lingual nerve damage. Lingual nerve injuries, often resulting from trauma, dental procedures, or maxillofacial surgeries, lead to significant functional impairments. Using computed tomography (CT) data, the custom protector is fabricated through 3D printing with a self-retaining structure to shield the lingual mucosa and nerve. The device effectively separates the lingual nerve from the surgical field without requiring retraction of the lingual flap, thereby reducing the risk of nerve injury and enhancing the safety and ease of the procedure.

Pharmacy 2050: A New Clinical and Patient Experience

With the changing demographics of the US population and evolving shift in urban design, the physical experience at the community level will change how health care is delivered. This will allow for more personalized and localized care complemented by digital technologies and smart devices over the next 25 years. At the same time, the evolution of clinical research with prevention, vaccinations, 3D printing, drone delivery, CRISPR, and implantables, will change the pharmaceutical landscape. Pharmacists and pharmacies have an opportunity to evolve with these changes making their role an integral part of the care team, but it is important that regulations and reimbursement also change. By 2050, pharmacists may play very different roles from clinical specialists to digital coaches and use data, AI, and technology to help drive outcomes while robots and technology automate many of their current repetitive tasks.

Optimization of three-dimensional Tesla valve-based passive micromixer for gradient functional materials mixing

With the rapid development of three-dimensional (3D) printing technology, the field of multi-material fabrication, particularly in the production of functionally graded materials, has achieved revolutionary advancements. However, the structures of micromixers, which are central to this technology, have not been sufficiently studied. This study introduces an optimized passive micromixer design based on a 3D Tesla valve, specifically engineered for the efficient mixing of Fe3O4 particles within an epoxy resin E51 matrix. The micromixer leverages the fluid dynamics of the Tesla valve, where sudden changes in flow direction generate secondary flows that enhance mixing performance by disrupting laminar flow and inducing chaotic advection, thereby increasing the interfacial area between different material components. This process significantly improves mixing efficiency in the fabrication of gradient materials. Through theoretical analysis and computational simulations, the study identifies optimal configurations for the Tesla valve system, emphasizing mixing dynamics that enhance material gradient formation. The findings reveal that optimal mixing efficiency is achieved with a configuration comprising three Tesla valves. This optimal setup includes a 0.5-mm opening width at the turning point, an immediate transition from the turning point to the straight pipe (0 mm length), a 0.25-mm structural height for the Tesla valve, and an outlet distance of 0.25 mm from the curved pipe. Hopefully, this study can provide a robust reference for the significant potential of future applications in the realm of multi-material 3D printing, thereby fostering its substantial growth prospects.

LabEmbryoCam: An opensource phenotyping system for developing aquatic animals

Phenomics is the acquisition of high-dimensional data on an individual-wide scale and is proving transformational in areas of biological research related to human health including medicine and the crop sciences. However, more broadly, a lack of accessible transferrable technologies and research approaches is significantly hindering the uptake of phenomics, in contrast to molecular-omics for which transferrable technologies have been a significant enabler. Aquatic embryos are natural models for phenomics, due to their small size, taxonomic diversity, ecological relevance, and high levels of temporal, spatial and functional change. Here, we present LabEmbryoCam, an autonomous phenotyping platform for timelapse imaging of developing aquatic embryos cultured in a multiwell plate format, and while optimised for embryos, the instrument is extremely versatile. The LabEmbryoCam capitalises on 3D printing, single board computers, consumer electronics and stepper motor enabled motion. These provide autonomous X, Y and Z motion, a web application streamlined for rapid setup of experiments, user email notifications and a humidification chamber to reduce evaporation over prolonged acquisitions. Downstream analyses are provided, enabling automated embryo segmentation, heartbeat detection, motion tracking, and energy proxy trait (EPT) measurement. LabEmbryoCam is a scalable, and flexible laboratory instrument, that leverages embryonic and early life stage organisms to tackle key global challenges including biological sensitivity assessment, toxicological screening, but also to support broader engagement with the earliest stages of life.