Advances In 3D Printing Research Articles

Polymeric Microneedles: An Emerging Paradigm for Advanced Biomedical Applications

Microneedles are gaining popularity as a new paradigm in the area of transdermal drug delivery for biomedical and healthcare applications. Efficient drug delivery with minimal invasion is the prime advantage of microneedles. The concept of the microneedle array provides an extensive surface area for efficient drug delivery. Various types of inorganics (silicon, ceramic, metal, etc.) and polymeric materials are used for the fabrication of microneedles. The polymeric microneedles have various advantages over other microneedles fabricated using inorganic material, such as biocompatibility, biodegradation, and non-toxicity. The wide variety of polymers used in microneedle fabrication can provide a broad scope for drug delivery and other biomedical applications. Multiple metallic and polymeric microneedles can be functionalized by polymer coatings for various biomedical applications. The fabrication of polymeric microneedles is shifting from conventional to advanced 3D and 4D printing technology. The multifaceted biomedical applications of polymeric microneedles include drug delivery, vaccine delivery, biosensing, and diagnostic applications. Here, we provide the overview of the current and advanced information on polymers used for fabrication, the selection criteria for polymers, biomedical applications, and the regulatory perspective of polymer-based and polymer-coated microneedles, along with a patent scenario.

Binder-free Three-dimensional (3D) printing of Cellulose-ZIF8 (CelloZIF-8) for water treatment and carbon dioxide (CO2) adsorption

Metal-organic frameworks (MOFs) have advanced several applications, including energy, biomedical and environmental remediation. However, most of the reported MOF materials are in powder form limiting their applications. This study reported the processing of MOF via three-dimensional (3D) printing of cellulose-MOFs (denoted as CelloMOFs). The 3D printing procedure involved a one-pot method including three steps: gel formation, 3D printing, and in-situ growth of MOF crystals. This procedure offered 3D printing of CelloMOF via a binder-free method with high loading of 67.5 wt%. The 3D-printed porous structures were used as adsorbents for carbon dioxide (CO2), dye, and heavy metal ions. They can be also used as catalysts for the degradation of water pollutants such as organic dyes. The materials can be separated easily without requiring extra procedures such as centrifugation or filtration. The materials offered complete (>99%) removal of organic dyes within 10 min with high selectivity toward anionic dyes e.g, methyl blue (MeB). The materials exhibited CO2 and heavy metal ions adsorption capacities of 0.63 mmol/g (27.7 mg/g) and 8–328 mg/g, respectively, with good recyclability. Our methodology will open new venues for advanced 3D printing of CelloMOF and its applications for water treatment and air purification.

Mechano-luminescence Behavior of Lanthanide-Doped Fluoride Nanocrystals for Three-Dimensional Stress Imaging.

Pervasive mechanical force in nature and human activities is closely related to intriguing physics and widespread applications. However, describing stress distribution timely and precisely in three dimensions to avoid "groping in the dark" is still a formidable challenge, especially for nonplanar structures. Herein, we realize three-dimensional (3D) stress imaging for sharp arbitrary targets via advanced 3D printing, owing to the use of fluoride nanocrystal(NC)-based ink. Notably, a fascinating mechano-luminescence (ML) is observed for the homogeneously dispersed NaLuF4:Tb3+ NCs (∼25 nm) with rationally designed deep traps (at 0.88 and 1.02 eV) via incorporating Cs+ ions and using X-ray irradiation. Carriers captured in the corresponding traps are steadily released under mechanical stimulations, which enables a ratio metric luminescence intensity based on the applied force. As a result, a significant mechano-optical conversion and superior optical waveguide of the corresponding transparent printed targets demonstrate stress in 3D with a high spatial and temporal resolution based on stereovision. These results highlight the optical function of the 3D-printed fluoride NCs, which cast light into the black boxes of stress described in space, benefiting us in understanding the ubiquitous force relevant to most natural and engineering processes.

3D Printing of MXenes-Based Electrodes for Energy Storage Applications

Energy storage devices (ESD) including batteries, and supercapacitors are becoming progressively imperative in the transition to a renewable energy future, as they enable the integration of intermittent renewable sources into the grid and provide backup power during outages. There are already reviews available on various energy storage materials and systems. However, the challenges in the choice of suitable materials and fabrication technology are yet to establish for the commercialization of affordable and efficient ESDs in every aspect of practical needs. Therefore, we realize that the review on the newly developed two-dimensional (2D) MXenes-based energy storage electrodes and devices fabricated through suitably advanced 3D printing technology is the need of the hour, and will be able to attract broad audiences of the related field. MXenes are a class of 2D materials having lamella structures that have shown great promise for energy storage applications due to their versatile redox behavior, high surface area, high electrical conductivity, and ability to accommodate intercalated ions. However, the processing of 2D MXenes suffers from serious agglomeration due to weak Van der Waals attraction and reduces its actual energy storage performances. In a few recent studies, it is observed that advanced 3D printing has enabled the fabrication of MXenes with complex and customized geometries, opening up new possibilities for developing high-performance energy storage devices. Therefore, this review is important for a comprehensive discussion on this topic. So, in this review, we discuss the recent breakthroughs in 3D printed MXene-based batteries and supercapacitors, the advantages of using 3D printing for the fabrication of tailor-designed MXenes-based ESDs, existing challenges, and the opportunities available for further exploration towards the successful commercialization of ESDs. Overall, this review is an insightful articulation for the future seeking to stay at the forefront of this exciting and rapidly-expanding field.

Advanced 3D Printing Materials: A Short Review of Polymers and their Composites

Advanced 3D Printing Materials: A Short Review of Polymers and their Composites

Advanced 3D Printing Materials: A Short Review of Polymers and their Composites

Advanced 3D Printing Materials: A Short Review of Polymers and their Composites

Advanced 3D Printing Materials: A Short Review of Polymers and their Composites

Advanced 3D Printing Materials: A Short Review of Polymers and their Composites

Fabrication of Architectured Biomaterials by Multilayer Co‐Extrusion and Additive Manufacturing

AbstractTissue engineering benefits from advances in 3D printing and multi‐material assembly to attain certain functional benefits over existing man‐made materials. Multilayered tissue engineering constructs might unlock a unique combination of properties, but their fabrication remains challenging. Herein, a facile process is reported to manufacture biomaterials with an engineered multilayer architecture, via a combination of co‐extrusion and 3D printing. Polymer filaments containing 5, 17, or 129 alternating layers of poly(lactic acid)/thermoplastic polyurethane (PLA/TPU) are produced, and explored for their use in fused deposition modeling (FDM) to fabricate scaffolds for cardiomyocyte culture. The co‐extruded filaments exhibit a layered architecture in their cross‐section with a continuous interface, and the integrity and alignment of the layers are preserved after 3D printing. The 17 alternating layers PLA/TPU composites exhibit excellent mechanical properties. It is envisaged that the multilayered architecture of the fabricated scaffolds can be beneficial for aligning cardiomyocytes in culture. It is found that the 17 alternating layers PLA/TPU significantly improve cardiomyocyte morphology and functionality compared to single phase materials. It is believed that this biomaterials fabrication scheme, combining a top‐down and bottom‐up approach, offers tremendous flexibility in producing a broad class of novel‐architectured materials with tunable structural design for tissue engineering applications and beyond.

3D-Printed Micro/Nano-Scaled Mechanical Metamaterials: Fundamentals, Technologies, Progress, Applications, and Challenges.

Micro/nano-scaled mechanical metamaterials have attracted extensive attention in various fields attributed to their superior properties benefiting from their rationally designed micro/nano-structures. As one of the most advanced technologies in the 21st century, additive manufacturing (3D printing) opens an easier and faster path for fabricating micro/nano-scaled mechanical metamaterials with complex structures. Here, the size effect of metamaterials at micro/nano scales is introduced first. Then, the additive manufacturing technologies to fabricate mechanical metamaterials at micro/nano scales are introduced. The latest research progress on micro/nano-scaled mechanical metamaterials is also reviewed according to the type of materials. In addition, the structural and functional applications of micro/nano-scaled mechanical metamaterials are further summarized. Finally, the challenges, including advanced 3D printing technologies, novel material development, and innovative structural design, for micro/nano-scaled mechanical metamaterials are discussed, and future perspectives are provided. The review aims to provide insight into the research and development of 3D-printed micro/nano-scaled mechanical metamaterials.

Phase separation strategy achieves printable corrosion-resistant ternary SiOC supercapacitors with sustained capacitance increase

Carbon-ceramic material with well-designed components and architectures is an effective strategy to fulfill the chemical-stability requirements of long-life supercapacitors. Herein, we proposed a direct cation-induced component recombination strategy to convert the intrinsically insulated SiOC ceramic to an electrochemically active ternary state for stable and long-life capacitive energy storage. Meanwhile, the cation-induced component recombination process can be directly coupled to advanced photocurable 3D printing technology to create the integral ternary SiOC electrode with various 3D structures for a complex-shaped supercapacitor. As a result, the ternary SiOC electrodes with four-type triply periodic minimal surface structures have been successfully printed and used in an alkaline supercapacitor with high corrosivity. The integral ternary SiOC electrode with Diamond structure demonstrates high capacity (756 mF·g−1 at 1.7 mA·g−1). The symmetrical supercapacitor based on ternary SiOC electrodes with a Diamond structure exhibits outstanding long-term durability (181.5 % capacity retention after 10,000 cycles) in highly corrosive environments. In addition, the ternary SiOC electrode also shows extremely high cycling stability in highly corrosive seawater, with a capacity retention rate of over 95 % after 20,000 cycles. Therefore, this novel 3D-printed ternary SiOC electrodes provides an efficient approach for developing long-term stable and reliable supercapacitors for applications in highly corrosive environments.

Manufacturing flow batteries using advanced 3D printing technology—A review

In the past decade, electrochemical energy storage systems such as rechargeable batteries have been explored as potential candidates for the large-scale storage of intermittent power sources. Among these, redox flow batteries stand out due to their low fabrication costs, high scalability, and long cycle life. Several redox flow battery pilot plants with MWh capacity have been constructed worldwide, although their commercial profitability is currently under investigation. 3D printing as a burgeoning technology offers unlimited opportunities in the process of optimizing the design, performance, and fabrication cost of redox flow batteries as compared to traditional top-down manufacturing techniques. This review discusses the principles of various redox flow batteries and 3D printing techniques, followed by explaining the advantages, disadvantages, and major factors to consider when using 3D printing in the construction of efficient redox flow batteries. The practical applications of 3D printing for redox flow batteries with different redox chemistries in the past decade are critically summarized, including classical all-vanadium, Zn/Br, and novel competitors. Lastly, a summary is provided along with outlooks that may provide valuable guidance for scientists interested in this research frontier.

How 3D-Printing Is Changing RF Front-End Design for Space Applications

3D-printing is leading to a major transformation in many industrial and application sectors, ranging from medical to aerospace. In the space sector, 3D-printing has firstly been adopted for the development of structural and thermal parts, such as brackets and heat pipes. In more recent years, thanks to improvements in precision and surface roughness, 3D-printing technologies have steadily been investigated also for the development of radio frequency components and advanced payloads. Indeed, the unique features of 3D-printing, including the free-form capability and the ease for customization, make these manufacturing technologies very appealing in the development of complex radio-frequency front-ends for space applications, including New Space constellations and next generation software-defined communication satellites. They also enable a drastic simplification of mechanical designs by reducing the number of interfaces and assembling screws of large radio-frequency front-ends, thus leading to significant mass savings and higher integration. This paper briefly reports on recent advances in 3D-printing that have been carried out according to the current trends in radio-frequency front-ends for satellite communications.

835 Rapid Prototyping, Digital Sculpting, and Computer Aided Design for Point of Care 3D Printed Stereo EEG Models

INTRODUCTION: Part of the workup for surgical management of epilepsy is stereotactic placement of intracranial depth electrodes to better understand the origin and network pattern of spread of seizures. To facilitate surgical decision making, epilepsy team discussion, and patient/family communication, a workflow was developed to create 3D printed models of sEEG patient brains and electrode locations which could be invaluable in explaining EEG results and surgical options. METHODS: Pre-op MRI and post-implantation CT scans of a sEEG case were imported and merged using 3D Slicer, a free and open-source software package for advanced medical imaging research.The CT was segmented to include only the high-density metallic electrodes. These 3D models were exported into Autodesk Fusion 360, a computer-aided design (CAD) program, where electrode models were designed based on their location on the CT scan. These models were exported to Maxon Zbrush to be cleaned and re-meshed to make the model easier to sculpt and manipulate.The electrode objects were used as cutting tools to create holes in the brain model. Finally, the relevant portion of the brain (right temporal lobe and surrounding regions) and electrodes were exported for 3D printing. The final models were 3D printed on a FormLabs Form 3 stereolithography (SLA) printer using clear resin for the brain and flexible grey resin for the electrodes. RESULTS: CONCLUSIONS: A workflow was devised to print anatomic models of brains implanted with electrodes for seizure monitoring in 2-3 days utilizing software from multiple disciplines including medical imaging, CAD/engineering, and 3D sculpting used in the film and video game industries. Future models will include further anatomical definition with more advanced 3D sculpting and printing techniques.

Hybrid Optimization of Green Supply Chain Network and Scheduling in Distributed 3D Printing Intelligent Factory

Considering the advantages of 3D printing, intelligent factories and distributed manufacturing, the 3D printing distributed intelligent factory has begun to rise in recent years. However, because the supply chain network of this kind of factory is very complex, coupled with the impact of customized scheduling and environmental constraints on the enterprise, the 3D printing distributed intelligent factory is facing the great challenge of realizing green supply chain networks and optimizing production scheduling at the same time, and thus a theoretical gap appears. This paper studies the hybrid optimization of green supply chain networks and scheduling of the distributed 3D printing intelligent factory. Firstly, according to the green supply chain network architecture of the distributed 3D printing intelligent factory, the cost minimization model is constructed. Secondly, mathematical software is used to solve the model, and the scheduling plan can be worked out. Finally, through the simulation analysis, it is concluded that the influencing factors such as demand, factory size and production capacity complicate the production distribution, and it can be observed that the carbon emission cost has gradually become the main factor affecting the total cost. The study has a reference value for the management decision making of the distributed 3D printing intelligent factory under the background of carbon emissions.

Two‐Photon Polymerization Lithography for Optics and Photonics: Fundamentals, Materials, Technologies, and Applications

AbstractThe rapid development of additive manufacturing has fueled a revolution in various research fields and industrial applications. Among the myriad of advanced 3D printing techniques, two‐photon polymerization lithography (TPL) uniquely offers a significant advantage in nanoscale print resolution, and has been widely employed in diverse fields, for example, life sciences, materials sciences, mechanics, and microfluidics. More recently, by virtue of the optical transparency of most of the resins used, TPL is finding new applications in optics and photonics, with nanometer to millimeter feature dimensions. It enables the minimization of optical elements and systems, and exploration of light‐matter interactions with new degrees of freedom, never possible before. To review the recent progress in the TPL related optical research, it starts with the fundamentals of TPL and material formulation, then discusses novel fabrication methods, and a wide range of optical applications. These applications notably include diffractive, topological, quantum, and color optics. With a panoramic view of the development, it is concluded with insights and perspectives of the future development of TPL and related potential optical applications.

Comparison of Shape Optimization Methods for Heat Exchanger Fins Using Computational Fluid Dynamics

Inverse design techniques are one way to leverage advances in 3D printing, artificial intelligence, and computational resources to achieve increased performance of heat exchangers. Two optimization techniques (genetic algorithm and particle swarm) and three geometry representations (binary level set, composite Bézier, and free form deformation) are used to increase the heat transfer and reduce the pressure drop of a heat exchanger fin. After running 210,810 OpenFOAM simulations, results indicate that a significant performance increase of the fin can be realized in less than 48 hrs, allowing for such a process to be integrated in traditional design processes. The best design increased the performance of the objective function, compared to the baseline rectangular geometry by 75%. A custom distributed infrastructure was built, allowing for all methods to reach 95% of the final objective values in a little over 4 hrs, handling 1674 OpenFoam simulations per hour.

Dual Material Fused Filament Fabrication via Core–Shell Die Design

In this work a fused filament fabrication (FFF) die design, capable of extruding two thermoplastics simultaneously in a core–shell configuration, is demonstrated as a means to produce composite structures in a single step. Despite the enormous advancements in 3D printing, fabrication of FFF objects with a composite structure remains a challenge due to the difficulty in finding dies to extrude such structures. We used polyethylene terephthalate glycol (PETG) and high-density polyethylene (HDPE) filaments to perform core–shell 3D printing. HDPE is one of the most commonly produced plastics but rarely used in FFF due to the severe warpage caused by volume changes upon its crystallization. Rheological and thermal analyses suggest the use of HDPE as a shell material due to its extremely short reptation time and sharp melting peak that facilitate superior surface contact and interlayer weld strength at the interface between neighboring FFF tracks. PETG is a commonly used 3D printing filament with excellent printability and sufficient zero shear viscosity to help maintain the extruded filament shape against shrinkage induced by the HDPE shell. Impact and tensile properties of core–shell objects revealed tremendous improvements in the impact resistance and toughness especially at 30 vol % HDPE shell with 1280% and 150% enhancement in impact resistance when compared to individual components: PETG and HDPE, respectively. Scanning electron microscopy was used to analyze the fracture morphology of the tested specimens to obtain an understanding of the fracture mechanism leading to the increased impact resistance. Using this die design can help open avenues of fabricating high impact resistance materials suitable for high performance applications and using HDPE in 3D printed objects with its superior solvent resistance.

Microfluidic Organ-on-A-chip: A Guide to Biomaterial Choice and Fabrication.

Organ-on-A-chip (OoAC) devices are miniaturized, functional, in vitro constructs that aim to recapitulate the in vivo physiology of an organ using different cell types and extracellular matrix, while maintaining the chemical and mechanical properties of the surrounding microenvironments. From an end-point perspective, the success of a microfluidic OoAC relies mainly on the type of biomaterial and the fabrication strategy employed. Certain biomaterials, such as PDMS (polydimethylsiloxane), are preferred over others due to their ease of fabrication and proven success in modelling complex organ systems. However, the inherent nature of human microtissues to respond differently to surrounding stimulations has led to the combination of biomaterials ranging from simple PDMS chips to 3D-printed polymers coated with natural and synthetic materials, including hydrogels. In addition, recent advances in 3D printing and bioprinting techniques have led to the powerful combination of utilizing these materials to develop microfluidic OoAC devices. In this narrative review, we evaluate the different materials used to fabricate microfluidic OoAC devices while outlining their pros and cons in different organ systems. A note on combining the advances made in additive manufacturing (AM) techniques for the microfabrication of these complex systems is also discussed.

Biocompatibility and osteointegration capability of β-TCP manufactured by stereolithography 3D printing: In vitro study.

Beta-tricalcium phosphate (β-TCP) bioceramics have an inorganic composition similar to the human bone. While conventional methods can only produce ceramic scaffolds with poor controllability, the advancement of 3D-printing, especially stereolithography, made it possible to manufacture controllable, highly precise, micropore ceramic scaffolds. In this study, the stereolithography was applied to produce β-TCP bioceramics, while ZrO2, Al2O3, Ti6Al4V, and polyetheretherketone (PEEK) were used as controls. Phase analysis, water contact angle tests, and Micro-CT were applied to evaluate the surface properties and scaffold. Hemolytic toxicity, cell proliferation, and morphological assessment were performed to evaluate the biocompatibility. Alkaline phosphatase (ALP) level, mineralization, and qRT-PCR were measured to evaluate the osteointegration. During the manufacturing of β-TCP, no evident impurity substance and hemolytic toxicity was found. Cells on β-TCP had good morphologies, and their proliferation capability was similar to Ti6Al4V, which was higher than the other materials. Cells on β-TCP had higher ALP levels than PEEK. The degree of mineralization was significantly higher on β-TCP. The expression of osteogenesis-related genes on β-TCP was similar to Ti6Al4V and higher than the other materials. In this study, the β-TCP produced by stereolithography had no toxicity, high accuracy, and excellent osteointegration capability, thus resulting as a good choice for bone implants.

Predicting the Bending of 3D Printed Hyperelastic Polymer Components

The advancement of 3D printing has led to its widespread use. NinjaFlex®, a thermoplastic polyurethane (TPU) filament, is a highly durable and flexible material that has been used to create flexible parts. While this material has been available for nearly two decades, the mechanical properties of 3D printed NinjaFlex® parts are not well-understood, especially in bending. The focus of this research was predicting the behavior of small 3D printed NinjaFlex® components. Three-dimensionally printed rectangular specimens of varying lengths and aspect ratios were loaded as cantilevers. The deflection of these specimens was measured using a computer. The experimental results were compared to a modified form of the Euler-Bernoulli Beam Theorem (MEB), which was developed to account for nonlinearities associated with large deflection. Additionally, experimental results were compared to the finite element analysis (FEA). The results showed that both modeling approaches were overall accurate, with the average difference between experimental deflection data and MEB predictions ranging from 0.6% to 3.0%, while the FEA predictions ranged from 0.4% to 2.4%. In the case of the most flexible specimens, MEB underestimated the experimental results, while FEA led to higher retraction.