Rapid Prototyping Research Articles

FRESH 3D Bioprinting of Collagen Types I, II, and III.

Collagens play a vital role in the mechanical integrity of tissues as well as in physical and chemical signaling throughout the body. As such, collagens are widely used biomaterials in tissue engineering; however, most 3D fabrication methods use only collagen type I and are restricted to simple cast or molded geometries that are not representative of native tissue. Freeform reversible embedding of suspended hydrogel (FRESH) 3D bioprinting has emerged as a method to fabricate complex 3D scaffolds from collagen I but has yet to be leveraged for other collagen isoforms. Here, we developed collagen type II, collagen type III, and combination bioinks for FRESH 3D bioprinting of millimeter-sized scaffolds with micrometer scale features with fidelity comparable to scaffolds fabricated with the established collagen I bioink. At the microscale, single filament extrusions were similar across all collagen bioinks with a nominal diameter of ∼100 μm using a 34-gauge needle. Scaffolds as large as 10 × 10 × 2 mm were also fabricated and showed similar overall resolution and fidelity across collagen bioinks. Finally, cell adhesion and growth on the different collagen bioinks as either cast or FRESH 3D bioprinted scaffolds were compared and found to support similar growth behaviors. In total, our results expand the range of collagen isoform bioinks that can be 3D bioprinted and demonstrate that collagen types I, II, III, and combinations thereof can all be FRESH printed with high fidelity and comparable biological response. This serves to expand the toolkit for the fabrication of tailored collagen scaffolds that can better recapitulate the extracellular matrix properties of specific tissue types.

Advancements in Artificial Intelligence-mediated Fabrication of 3D, 4D, and 5D Printed for Fabrication of Drug Delivery Formulations

: One of the most powerful and inventive fabrication techniques used to create novel structures and solid materials using precise additive manufacturing technology is 5D and 4D printing, which is an improved version of 3D printing. It catches people's attention because of its capacity to generate fast, highly complex, adaptable product design and fabrication. Real-time sensing, change adaptation, and printing state prediction are made possible by this technology with the use of artificial intelligence (AI). The process of 3D printing involves the use of sophisticated materials and computer-aided design (CAD) with tomography scanning controlled by artificial intelligence (AI). The printing material is deposited according to the specifications of the file, typically in STL format; however, the printing process takes time.4D printing, which incorporates intelligent materials with time as a fourth dimension, can solve this drawback. About 80% of the time will be saved by this technique's self-repair and self-assembly qualities. One limitation of 3D printing is that it cannot print complex shapes with curved surfaces. However, this limitation can be solved by using 5D printing, which uses rotation of the print bed and extruder head to achieve additive manufacturing in five different axes. Some printed materials are made sensitive to temperature, humidity, light, and other parameters so they can respond to stimuli. With its effective and efficient manufacturing for the necessary design precision, this review assesses the potential of these procedures with AI intervention in medicine and pharmacy.

Continuous fiber printing of a modular heater for ion mobility spectrometry

Ion mobility spectrometry (IMS) is a powerful analytical method for separating and detecting gaseous substances like volatile organic compounds (VOCs). It is highly versatile, used both as a standalone technique and in combination with chromatographic methods for pre-separation or mass spectrometry for complex matrix analysis. This study explores the use of an advanced 3D printing technology to print a heater for an IMS-device.A continuous fiber printer, commonly used to enhance the mechanical properties of printed objects, was used to create a customized heating element by embedding a copper wire within the polymer matrix during the printing process. Cyclic olefin copolymer (COC) was chosen as the matrix material due to its analytical properties, such as low off-gassing and higher thermal stability, compared to the more commonly used polylactic acid (PLA).The 3D printed heater was incorporated into a drift tube ion mobility spectrometer, and its performance was evaluated by analyzing the separation of various ketones. The results show that the 3D printed heater effectively controlled the temperature within the drift tube, improving the resolving power of overlapping peaks.This study shows the potential of 3D printing technology to improve fabrication and functionality of IMS devices. The flexibility in design and material selection afforded by 3D printing not only enhances the analytical performance of IMS but also allows for customization and rapid prototyping of other analytical instruments or laboratory devices.

Crossing Domains: The Role of Transfer Learning in Rapid AI Prototyping and Deployment

In the changing world of technology today it's crucial for AI advancements to meet the increasing need for efficiency and top-notch performance. One major hurdle in developing and implementing AI solutions is the requirement, for sets of specialized data and computing power which often slows down progress. Conventional machine learning models usually demand starting from scratch with each project result in significant time and financial investments. Transfer learning is a game changer as it allows the sharing of expertise and pre-existing models from one area to assist with tasks in another domain seamlessly bridging the gap between them This method significantly lessens the reliance on datasets lowers computational requirements and speeds up the overall process of developing AI technologies In this piece we delve into how transfer learning is pivotal in transferring knowledge across domains especially beneficial, for quickly prototyping and deploying AI solutions In our analysis of different uses like natural language processing and medical diagnostics as well as computer vision applications we show how transfer learning boosts effectiveness in scenarios with limited data availability and speeds up the implementation of models while also allowing for better adjustments to pre trained models for particular tasks. Additionally, we explore the potential ahead for transfer learning to support the development of AI models that are easily customized for new tasks, in various fields rapidly. The growing access to trained models and the ongoing progress, in transfer learning methods are setting the stage for AI to be more user friendly and effective – enabling industries to drive innovation and roll out solutions at an unprecedented speed. Keywords: Transfer Learning, AI Prototyping, AI Deployment, Pre-trained Models, Cross-Domain Applications, Machine Learning, Natural Language Processing, Computer Vision, Medical Imaging, Model Fine-tuning, Data Scarcity, Scalability in AI.

Optimal Prototyping with Noisy Measurements

Problem definition: Prototyping and testing are an integral part of almost any new product development process, helping firms navigate the inherent uncertainties of creating new products. Recent developments in rapid prototyping, including technologies that enable cheaper low-fidelity tests, have opened up the possibilities for firms in reconfiguring their product development processes. Firms can, by choosing the level of evaluation fidelity, alter the traditional cost-quality trade-offs inherent in sequential prototyping. Methodology/results: The current article formulates a general model of sequential search where firms can proceed by obtaining noisy low-fidelity evaluations of their prototypes. Our results demonstrate that the imperfect fidelity of evaluations alters the firm’s optimal experimentation, with the starkest difference being that it may make it optimal for the firm to select and launch a prototype that did not yield the best evaluation. In addition, our analysis of optimal measurement technology reveals that the focal firm should demand the most precise measurements when their ex-ante uncertainty is moderate (not too high or low). We also consider extensions analyzing how the optimal choice of evaluation fidelity is affected by the number of available prototypes, by operational flexibility (to dynamically change measurement technology), and by the ability to outsource evaluations to an experimentation platform. Managerial implications: We develop managerial insights for how the optimal choice of fidelity and the optimal length of the evaluation cycle should be planned depending on the evaluation costs and the firm’s ex-ante uncertainty. The resulting framework offers guidance to product and software development firms to successfully leverage imperfect fidelity experiments. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2024.1133 .

Investigating physical and mechanical properties of alumina/acrylonitrile butadiene styrene composites manufactured by fused deposition modeling

AbstractIn recent years, 3D printing technologies or additive manufacturing have gained significant attention in research and other industries. Among the various 3D printing techniques, fused deposition modeling has been the most widely adopted. This study focused on developing composite filaments by incorporating acrylonitrile butadiene styrene (ABS) with different volume percentages of aluminum oxide (alumina). The mechanical and physical properties of parts printed with these composite filaments were thoroughly evaluated. Tensile testing revealed that increasing the alumina content led to a reduction in tensile strength. At 20 vol%, tensile strength dropped by 72%. A heat deflection temperature (HDT) test indicated an 11% reduction in HDT, likely due to the defective composite structure. Thermogravimetric analysis test demonstrated improved thermal stability as alumina content increased. Linear shrinkage was measured in three directions, revealing anisotropic shrinkage patterns. Hardness tests were conducted, and a decrease was observed when the polymer was filled with alumina. Finally, the warpage was reduced by 91% as alumina content increased to 20%.Highlights Alumina/ABS composite filaments were manufactured and 3D‐printed very well. The void content in composite samples increases with alumina powders. The mechanical properties of 3D‐printed composite parts were decreased The alumina powder improves the warpage issues in 3D‐printed parts.

EXPLORING ELECTROMECHANICAL SYSTEMS IN THE DEVELOPMENT OF NEXT-GENERATION ELECTRIC POWERTRAINS

In the rapidly evolving electric vehicle industry, the study of electromechanical systems in next-generation electric powertrains is of particular relevance. This is driven by the need to enhance energy efficiency, reduce costs, and improve the reliability of vehicles. The article examines the role of innovative materials, advanced design methods, and control algorithms in creating high-efficiency and reliable electric powertrains. Specifically, the impact of nanomaterials such as graphene and carbon nanotubes on reducing motor weight and increasing heat dissipation is analyzed, contributing to improved efficiency and extended driving range. The adoption of additive manufacturing (3D printing) and digital twins accelerates prototyping and component optimization in electric powertrains. Adaptive control algorithms ensure optimal system performance in real-time, enhancing overall efficiency and reliability. Research methods included the analysis of modern materials and technologies, prototyping using additive manufacturing, and the implementation of predictive and adaptive control algorithms. The results demonstrate significant improvements in the performance of electric powertrains due to the use of innovative materials and cutting-edge design technologies. Conclusions confirm that the application of advanced materials and adaptive control algorithms is critical for ensuring the sustainable development of the electric vehicle industry. Future research prospects focus on further refining materials and technologies to enhance scalability and reduce production costs, making electric powertrains more accessible and efficient.

The Use of Terahertz Computed Tomography and Time Domain Spectroscopy to Evaluate Symmetry in 3D Printed Parts

3D printing has become essential to many fields for its low-cost production and rapid prototyping abilities. As 3D printing becomes an alternative manufacturing tool, developing methods to non-destructively evaluate defects for quality control is essential. This study integrates the non-destructive terahertz (THz) analysis methods of terahertz time-domain spectroscopy (THz-TDS) and terahertz computed tomography (THz CT) to image and assess 3D printed resin structures for defects. The terahertz images were reconstructed using MATLAB, and the rotational symmetry of various structures before and after the introduction of defects was evaluated by calculating the mean squared deviation (MSD), which served as a symmetry parameter to indicate the presence of defects. Structures A and B had MSD values that were at least three standard deviations larger after introducing defects to their structures, showing a significant change in symmetry and indicating the existence of defects. Similarly, in structure C, blockages in parts made with different post-cures were identified based on the increase in MSD values for those slices. For structure D, the presence of a defect increased the MSD value by 14%. The results of this study verify that the MSD calculated for the rotational symmetry of the structures was greater when defects were present, accurately reflecting the anticipated breaks in symmetry. This paper demonstrates that terahertz imaging, combined with MSD analysis, is a viable procedure to identify and quantify defects in rotationally symmetric 3D printed structures.

Human-Centered Design to Respond to Public Health Crises: Maintaining Canine Rabies Vaccination during the COVID-19 Pandemic in Peru.

In the early coronavirus disease 2019 pandemic, limited understanding of severe acute respiratory syndrome coronavirus 2 transmission and fears of infection hindered mass dog vaccination efforts in dog rabies-affected areas. Interruption of dog rabies vaccination campaigns could lead to a rapid increase in the risk of human rabies. To address these challenges, we applied human-centered design (HCD) principles to develop a vaccination strategy that prioritizes safety while ensuring dog rabies vaccination continuity in Arequipa, Peru, a rabies-affected area. We describe the process of rapid prototyping and testing undertaken by our research team to adapt the vaccination process in response to a health crisis. A multidisciplinary team met twice a week to prototype a fixed-point vaccination campaign that ensured distancing and reduction of fomite transmission while allowing for the continuation of dog vaccination. Field notes and videos informed successive meetings. The final prototype was used in rabies hotspots. In 4 weeks, six prototypes of safe booths and supporting safety protocols were designed, and two copies of each prototype were field tested. During testing, additional innovations were identified and implemented, including virtual vaccine certificates and online data collection forms. The final prototype was implemented across 251 sites, and 17,876 dogs were vaccinated. Using HCD principles, we swiftly developed a mass vaccination strategy that provided safety and enabled the maintenance of rabies vaccination programs. This work highlights the importance of innovative and adaptive approaches to address public health challenges in times of crisis.

Design and Construction of Infrastructure Asset Management Information Systems Using the Rapid Application Development (RAD) Method

The school administration system manages several things, such as the management, storage, and use of facilities and infrastructure items, which have been done traditionally. In contrast, the management must be well structured so that integration with information technology is needed. In previous studies, there were many areas for improvement in the asset information system, one of which was the use of traditional methods such as waterfall which had weaknesses in user flexibility and took a long time to process. Therefore, that a more relevant and accurate method is needed in its completion. SD Khaijah Surabaya built a facilities and infrastructure asset information system using the Rapid Application Development (RAD) method, which offers a more adaptive and interactive solution because it allows the development of rapid prototypes and continuous evaluation of the system. The results of this study show that building an asset management information system can simplify the process of managing infrastructure assets, improve data accuracy, and assist in making decisions related to asset management. The implementation of this system is expected to significantly improve organizational performance in terms of asset management, while system testing using the Black Box method shows accurate results and using the System Usability Scale (SUS) method manages to get a precise score of 80. The average person gives a score of 5 on the assessment of the questionnaire distributed to stakeholders.

Directed energy deposited Fe36Ni35Al17Cr10Mo2 eutectic high entropy alloy: Hierarchical microstructure and tensile properties

Eutectic high entropy alloy (EHEA) has attracted much attention due to its outstanding properties, which are commonly fabricated through conventional manufacturing methods. Additive manufacturing (AM) techniques that can create near-net components provide opportunities for rapid prototyping EHEAs. This study elucidated the microstructural evolution mechanisms of Fe36Ni35Al17Cr10Mo2 EHEA fabricated by directed energy deposition (DED) via XRD, SEM, and EBSD. The dual-phase dendrite structure, micro-scale heterogeneous grains, and nano-scale BCC phases collectively formed the hierarchical microstructure in the DEDed alloy. We used neutron diffraction to demonstrate texture components and their relation to mechanical behaviors. {013}<100> texture possesses the highest Schmid factor compared to other textures, causing texture-induced softening of the FCC and B2 phases during tension. {233}<0 1‾ 1> texture exhibits the low SF and hard orientation for the B2 phase. Due to the synergistic plastic deformation between FCC and B2 phases and precipitation strengthening from the BCC phases, the DEDed Fe36Ni35Al17Cr10Mo2 exhibits an ultimate strength of ∼1267 MPa with an elongation of ∼20.1 % at room temperature. Moreover, the elevated-temperature tensile testing and crack analysis were employed to indicate the elevated-temperature fracture behaviors. We found that the nucleation and propagation of microcracks were suppressed at the phase boundary at elevated temperatures, avoiding brittleness and achieving excellent high-temperature mechanical properties. These results are expected to open ever-bright prospects for additive manufacturing Co-free high-performance EHEAs.

Rapid Prototyping of Multiscale Flexible Printed Circuit Boards With NeXus, a Robotic Additive Manufacturing System

Abstract This paper demonstrates the NeXus system, a multiscale robotic additive manufacturing platform developed at the Louisville Automation and Robotics Research Institute, as a rapid prototyping tool through additively manufacturing a multilayer flexible printed circuit board (FPC) with a printed strain sensor and soldered surface mounted devices (SMD). Manufacturing of the demonstrator requires the application and curing of multiple materials with specialized properties, tools for automated assembly, and software advances to streamline the process enabling the use of industry-standardized programs to command the NeXus system. Additive manufacturing processes supported by the NeXus include aerosol jet printing (AJP) for fine feature silver conducting lines, direct write ink-jet printing for insulating materials, and intense pulsed light (IPL) for curing materials between depositions. The NeXus system transports and manipulates parts using a six-degree-of-freedom (DOF) high-precision positioner. Solder paste deposition and pick-and-place (PnP) procedures are performed by a 4DOF Selective Compliance Articulated Robot Arm (SCARA). Conversion methods between traditional printed circuit board (PCB) design software and production-ready command scripts were developed to translate basic drawings into command scripts. Multilayer structures with AJP 50-μm wide lines, an insulating bridge with a thickness of around 100 μm, and SMDs soldered to silver AJP pads were integrated within the demonstrator. An operational amplifier and other SMDs reduce the complexity of the accompanying control circuit and amplify the sensor's response by 1830 times. The successful fabrication of the demonstrator FPC highlights the rapid prototyping ability of the NeXus system.

3D Printing and Additive Manufacturing: Revolutionizing the Production Process

Additive manufacturing (AM), widely known as 3D printing, is revolutionizing production processes across industries by enabling customization, reducing waste, and enhancing efficiency. This paper explores the fundamentals of AM, its applications in healthcare, aerospace, consumer goods, and construction, and its benefits, including complex geometries and sustainability. It also addresses challenges such as material limitations, regulatory hurdles, and high costs, while highlighting emerging trends like hybrid manufacturing, bioprinting, AI integration, and nanoprinting. Future directions emphasize scaling production, improving education, and fostering global collaboration to unlock the full potential of AM.

4D Direct Laser Writing for Intelligent Micromachines

AbstractIntelligent micromachines are devices with sizes ranging from submillimeters to nanometers, capable of performing complex tasks adaptively at small scales. Smart micromachines have recently been developed that exhibit shape‐morphing capability in response to various stimuli to adapt to their environment. However, for such micromachines to be effective in harsh environments, micromachines should be more than adaptive. Essentially, they must exhibit a high degree of intelligence, characterized by enhanced locomotion capability, self‐adaptability, programmability, reconfigurability, and multifunctionality. 4D direct laser writing has enabled the rapid prototyping of stimulus‐responsive adaptive micromechanisms and diverse functional microcomponents, including microscale sensors, actuators, data processors, memory structures, and power‐supply structures. This review provides a comprehensive overview of the current state of the art in 4D microprinting technology based on two‐photon polymerization for the intelligentization of micromachines. Further, it offers insights into the fabrication of intelligent micromachines via the integration of diverse functional components through the 4D direct laser writing technology.

3D Printing of a Chitosan and Tamarind Gum Ink: a Two-Step Approach.

3D bioprinting stands out as one of the most promising innovations in the field of high technologies for personalized biomedicine, enabling the fabrication of biomaterial-based scaffolds designed to repair, restore, or regenerate tissues and organs in the body. Among the various materials used as inks, hydrogels play a critical role due to their unique characteristics, including excellent biocompatibility, adjustable mechanical properties, and high solvent retention. This versatility makes them ideal for various applications such as biomedical devices, drug delivery, or flexible electronics. Although chitosan is a promising material for such applications, when used alone, it does not possess the necessary strength and stiffness for creating high-resolution 3D bioprinted structures. In this study, we propose a combined method for the fabrication of self-supporting 3D printed objects with an ink made of chitosan and tamarind gum. Our approach involves two key techniques. The first one is a controlled evaporation of the solvent, aiming to increase the concentration of the components of the ink. The second one relies on printing in a gelling bath composed of sodium hydroxide and ethanol, allowing for improved printability and long-term stability of the scaffolds. The results obtained revealed the possibility of modulating the concentration of the components based on the heating time. The latter positively influences not only the ink printability but also the properties of the resulting scaffolds such as their biodegradability and mechanical properties.

A high sensitivity, low cost and fully decoupled multi-axis capacitive tactile force sensor for robotic surgical systems.

This paper presents the design of a multi-axis capacitive tactile force sensor with a fully decoupled output response for input normal and shear forces. A patterned elastomer is used as a dielectric layer between capacitive electrodes of the sensor that allows to achieve relatively higher sensitivity. The sensor is fabricated utilizing a low-cost rapid prototyping technique and is characterized for normal and shear forces in the range of 0 ~ 10 N and 0 ~ 3.1 N respectively. The achieved force sensitivity for the normal axis is 2.03%/N and for shear axes is 1.67%/N. The difference between the estimated force from the sensor and actual force applied is negligible, which demonstrates the accuracy of the sensor. The reliability of the sensor is analysed by performing hysteresis and repeatability tests. The hysteresis error is found to be 4.94% and 4.69% for normal and shear forces respectively. The repeatability error of the sensor is less than 5%, which shows the stability of the sensor. The high sensitivity, linear output response, high force measurement range, reliability and low cost make the proposed tactile sensor suitable for the force feedback in the robotic surgical systems.

Rapid Prototyping for Accelerated Establishment of Film Processing‐Performance Relationships in Silicon Phthalocyanine OFETs

AbstractUnderstanding the complex relationships underlying the performance of organic electronic devices, such as organic field‐effect transistors (OFETs), requires researchers to navigate a multi‐dimensional parameter space that includes material design, solution formulation, fabrication parameters, and device geometry. Herein, a recently developed materials acceleration platform is demonstrated, named the RoboMapper, to perform direct on‐chip fabrication of OFETs by ultrasonic meniscus printing using silicon phthalocyanine (SiPc) derivatives as the semiconductor. OFETs using bis(tri‐n‐butylsilyl oxide) SiPc ((3BS)2‐SiPc) exhibited the best device performance characterized by the highest electron field‐effect mobility (µe). Through optical microscopy and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), the favorable performance of (3BS)2‐SiPc is attributed to the specific film morphology and molecular packing achieved with optimal print conditions. Investigating the impact of deposition parameters reveals the crucial role of solvent evaporation rate and print speed in achieving high‐quality film formation. Overall, optimal fabrication conditions for (3BS)2‐SiPc devices include slow print speeds and fast evaporating solutions achieved by using a mixture of co‐solvents and an elevated substrate temperature. The results of this work reveal distinct relationships between deposition conditions, film properties, and device performance for each SiPc derivative and emphasize the necessity of high throughput experimentation to comprehensively understand process‐performance relationships in organic semiconductors.

Vortex-enhanced jet impingement and the role of impulse generation rate in heat removal using additively manufactured synthetic jet devices

This article presents an approach to the design and fabrication of synthetic jet devices (SJDs) using rapid prototyping via additive manufacturing, marking the first study to employ this method for such devices. This manufacturing technique empowers researchers with complete design freedom, enabling the production of ultra-thin SJDs—as thin as 4 mm—without mechanical fasteners and facilitating the rapid fabrication of multiple devices with varying geometries. To showcase the potential of this method, SJDs with conical and cylindrical cavities and orifices ranging from 1.6 mm to 7 mm were designed, fabricated, and tested.These devices achieved air jet exit velocities exceeding 106 m/s using a single piezoelectric diaphragm—among the highest reported in the literature—validating the effectiveness of this manufacturing approach. This high jet velocity is significant for practical applications requiring efficient thermal management, such as cooling high-power-density electronics, where compact and energy-efficient solutions are essential. Beyond achieving high velocities, it was revealed that maximizing jet velocity alone is not always optimal for heat removal. The hydrodynamic impulse generation rate was introduced as a more significant factor influencing heat transfer performance. By fabricating and testing multiple SJDs with different geometries, it was demonstrated that the impulse generation rate, which accounts for both jet velocity and flow rate, better correlates with enhanced heat transfer capabilities than jet velocity alone. This insight addresses an often-overlooked parameter in SJD design and has substantial implications for optimizing heat removal performance. Moreover, lumped element modeling, tuned solely on diaphragm deflection behavior, accurately predicted device performance and was validated using a hotwire anemometer. This model effectively characterizes center-axis orifice devices and confirms its applicability to thin-cavity designs, providing a valuable tool for future SJD development. Despite moderate volume flow rates (0.2 to 0.8 m3/h), the fabricated SJDs delivered significant improvements in heat transfer. Compared to natural convection, these devices achieved over 13 times greater heat removal rates, with an average heat transfer coefficient exceeding 120 W/m2·K over a 30 mm × 30 mm heated surface. These findings demonstrate the practicality and effectiveness of vortex-enhanced synthetic jet impingement for targeted and efficient cooling of localized hot spots. This approach offers multiple advantages over traditional rotary cooling systems like fans, including increased reliability, lower profile, while consuming less than 100 mW. The ability to rapidly prototype and optimize SJDs using additive manufacturing accelerates research and development in this field, paving the way for advanced thermal management solutions in real-world applications.

Design, manufacturing, and multi-modal imaging of stereolithography 3D printed flexible intracranial aneurysm phantoms.

Physical vascular phantoms are instrumental in studying intracranial aneurysms and testing relevant imaging tools and training systems to provide improved clinical care. Current vascular phantom production methods have major limitations in capturing the biophysical and morphological characteristics of intracranial aneurysms with good fidelity and multi-modal imaging capacity. With stereolithography (SLA) 3D printing technology becoming more accessible, newer flexible and transparent printing materials with higher precision controls open the door for improving the efficiency and quality of producing anthropomorphic vascular phantoms but have rarely been explored for the application. This technical note intends to report the feasibility of using SLA 3D printing technology to manufacture flexible intracranial aneurysm phantoms with similar scales to the real anatomy, as well as their capacity for multi-modal flow imaging and analysis, including ultrasound flow imaging, high-speed filming, and particle image velocimetry analysis. We designed and 3D-printed two intracranial aneurysm phantoms with an SLA 3D printer using Formlabs Elastic 50A resin. By using a micropump to introduce cyclical flows in the phantoms, we first employed conventional Doppler and vector flow ultrasonography to observe and measure different fluidic properties. Then, a high-speed camera was used to record particles flowing within the phantom, and we further conducted a particle image velocimetry analysis, including the distribution of mean 2D velocity vectors, average velocity magnitudes, and the mean vorticity fields in the phantom for the high-speed imaging data. We successfully 3D-printed flexible intracranial aneurysm phantoms with similar dimensions to the real anatomy. Additionally, we validated the phantoms' ability to allow visualization, measurement, and analysis of flow dynamics based on both real-time ultrasound and optical imaging. Our proof-of-concept study illustrates that SLA 3D printing using commercial elastic resins can significantly contribute towards facilitating the fabrication of flexible intracranial aneurysms phantoms for training, research, and preoperative planning.

Additive and subtractive hybrid manufacturing assisted by femtosecond adaptive optics

Advanced micro–nano devices commonly require precise three-dimensional (3D) fabrication solutions for pre-designing and integrating 0D to 3D configurations. The additive–subtractive hybrid manufacturing strategy dominated by femtosecond laser direct writing has become an increasingly interesting technical route for material processing. In this study, a novel approach termed femtosecond adaptive optics-assisted hybrid manufacturing was proposed, which integrates subtractive (femtosecond laser ablation) and additive (two-photon polymerization) fabrication. In this hybrid manufacturing method, the introduction of adaptive optics offers parallel direct writing and wide-area material processing capabilities. To demonstrate the validity of the hybrid approach, on-chip surface plasmon polariton waveguides with strong sub-wavelength field confinement and enhanced functionality were successfully fabricated. In comparison with the terahertz-wave devices fabricated based on the focused ion beam technique, the functional tests in terahertz near-field microscopy show a rival performance fabricated with our hybrid approach. Besides, our cost-effective solution also dramatically reduces the fabricating time of excitation regions by a factor &gt;16. Our work provides a new inspiration in integrated photonics.