3D Printing and Additive Manufacturing最新文献

An in vitro colon model, particularly one suited to high throughput screening, has the potential to enhance understanding of cellular mechanisms and functions important in intestinal health and can be used for drug testing and drug permeation studies. While extensively studied, traditional monolayered cultures using immortalized colon cancer cell lines on transwell plates fail to accurately replicate the native intestinal epithelium's complex architecture. To address this limitation, we have developed a novel, facile photopolymerization technique to fabricate scaffolds that closely resemble colon crypts. We have further developed a method using screen printing to be able to coat these scaffolds while preserving the crypt architecture in order to vary the surface chemistry of these systems. This paper focuses on the development of three-dimensional crypt models that can be made with simple equipment and with chemical precursors that are commercially available to make building tissue models more accessible to the broader research community.

Materials based on the hydroxypropyl methylcellulose mixed with different biopolymers (BioP; 5 w% of chitosan, sodium alginate, apple pectin, or citrus pectin) were processed by hot-melt extrusion and 3D printing to produce capsules intended for controlled drug release. Microscopic analyses confirmed significant impact of BioP on the processing temperatures and quality of the 3D printing. The capsules' chemical composition had a more significant impact on the dissolution profiles in acidic and neutral media, which are a robust function of the intermolecular bonds and swelling characteristics of the particular BioP (as indicated by the combined results of Raman spectroscopy, differential scanning calorimetry [DSC], and thermogravimetry). The capsules of all tested compositions retained the model drug for 120 min in pH 1.2, i.e., fulfilled the condition of targeting the small intestine. The presence of the particular BioP was found to be particularly beneficial in the development of personalized capsules for oral administration. The addition of both pectins led to a relatively fast pH-independent release of the model drug and has the potential applications in the targeting of the duodenum or jejunum. The capsules containing alginate and chitosan exhibited later initial release in pH 1.2, guaranteeing an unaltered passage through the stomach environment.

Cranial reconstruction, cranioplasty, is conducted to repair skull defects caused by craniectomy following traumatic brain injury, stroke, or postoperative infection. Complications requiring implant removal occur in 10-20% of cases as the optimal cranioplasty material is not known. We describe the Cambridge University Hospital's (CUH) multidisciplinary cranial reparation service and aim to assess the safety of the workflow compared with existing technologies. We retrospectively analyzed the medical records of all patients who underwent cranioplasty via the CUH cranioplasty pathway with cranioplasty implants manufactured utilizing grade 23 Ti-6Al-4V powder bed fusion (PBF) between December 2017 and December 2021. The primary and secondary outcomes were implant removal and the occurrence of cranioplasty infections, respectively. We identified 107 cranioplasty procedures performed in 105 patients, who were followed for a median time of 34.9 months (interquartile range 46.7-17.7, range 2 days to 60.2 months). Twenty-four (22%) patients had at least one complication, and 11 (10%) cranioplasties had been removed because of complications. Thirteen (12%) patients had surgical site infections, but only eight (7%) cranioplasties had to be removed because of infections. Placement of a cerebrospinal fluid shunt (hazard ratio [HR] 8.57, 95% confidence interval [CI] 2.36-31.12) and high American Society of Anesthesiologists grade (HR 6.87, 95% CI 1.66-28.39) predicted shorter cranioplasty survival. We demonstrated the largest currently published series of titanium cranioplasties produced using PBF-the overall complication and removal rates (22% and 10%, respectively) were comparable with those reported in the literature. We have embedded the key steps and skills in the cranioplasty process in an academic setting allowing for tailored surgery and flexibility to develop further service innovations in the future. Patients with cerebrospinal fluid shunts and those in poor general condition were at increased risk of infections and subsequent cranioplasty failure.

The ability to customize products with additive manufacturing allows manufacturers to meet the unique requirements and functionality for individual applications. By printing dissolvable materials as a matrix material, the release of active agents over time can be tailored on a per part basis by varying both geometry and printed material properties. Direct printing of actives via filament material extrusion is challenging because many active agents become inactive at the elevated temperatures found in the melt-based process. This limitation is circumvented by in situ embedding the active agents into a priori designed voids of a printed water-soluble capsule. In this work, this process is demonstrated by the in situ deposition of liquids and powders into thin-walled, water-soluble, printed structures. The authors demonstrate the ability to tune dissolution time by varying the thickness of a printed part's walls in order to create a delay in release and by creating parts with multiple chambers to initiate a multistaged release. This ability provides opportunities for creating customized containers for the prescribed release of liquid and powdered active agents.

Electrohydrodynamic (EHD) technology is renowned for its significant advantages in high resolution and micro-nanoscale printing, demonstrating an immense potential in the development of micro-nano devices. During the printing process, it is inevitably influenced by different interferences, which result in printing errors that influence its printing precision. This article summarizes several research topics on printing errors of EHD printing technology, involving the sources, and correction of different types of printing errors. First, the induced factors of printing errors are summarized in details, which are used to categorize the error correction methods. Then, the existing correction methods are comprehensively summarized and analyzed according to the types of printing errors. Finally, the conclusions are provided, involving some potential research topics.

Additive manufacturing, particularly 3D-printing, has emerged as a crucial method for creating prototypes and specialized components in various scientific fields. This study investigates the biocompatibility and performance of 3D-printed materials, with focus on cyclic olefin copolymer (COC) in comparison with traditional materials such as polylactic acid (PLA) and COC combined with glass (Glass + COC) inlays. Biocompatibility is especially critical for cell-based research and millifluidic applications, impacting cell culture experiments and the interaction of 3D-printed structures with reactive substances. To investigate material influence, experiments were conducted using rat cardiomyocyte (H9c2) and human embryonal kidney (HEK293) cell lines, with comprehensive assays including lactate, lactate dehydrogenase (LDH), and thiazolyl blue tetrazolium bromide assays assessing metabolic activity, cell stress, and cell viability. Results demonstrated that Glass + COC exhibited increased metabolic activity and cell viability compared with standard polystyrene (PS) culture dishes, with COC and PLA materials showing comparable viability with standard PS dishes, although with slight differences favoring COC. Lactate assays revealed subtle increases in lactate secretion, notably in Glass + COC cultures, suggesting a correlation with cell viability. LDH assays provided insights into potential material-associated toxicity. Microscopy experiments visually confirmed cell growth and distribution within culture vials, using various transparent materials, including PLA foil, COC foil, standard microscope glass slides, and Glass + COC. Furthermore, atomic force microscopy (AFM) examined surface roughness and differences between the upper and lower surfaces of 3D-printed PLA and COC parts, contributing to the understanding of material surface characteristics. In conclusion, this study highlights the biocompatibility of 3D-printed materials for cell-based research, emphasizing the potential of COC and Glass + COC manufactured via 3D-printing for such applications. The interplay among cell viability, metabolic activity, and lactate levels underscores the importance of material selection. Microscopy and AFM analyses enhance the comprehension of cell growth behavior and surface properties, advancing the selection of 3D-printed materials for biocompatible applications.

Regenerative design lies on synergistic relationship between sociocultural and ecological systems, which can enable revolutionary boundaries for designing decision-making frameworks. Transitioning to regenerative design as a manifestation of systems thinking necessitates a fundamental shift from sustainable patterns and mechanistic design methodologies. At its core, regenerative design unlocks a holistic paradigm that fosters circular systems reliant on renewable resources, which can strive for equilibrium between creation and utilization. This framework goes beyond mere sustainability by actively engaging in the restoration and regeneration of its sources of energy and materials. It aspires to harness the inherent wisdom of nature, facilitating a comprehensive harmonious coexistence with environment. The integration of data-driven decision-making and regenerative paradigms can provide an insight for developing evidence-based solutions for strategic environmental and natural resource management through design practices. This short research presents a holistic data-driven and self-adaptive design strategy as the integrated problem-solver model under the imperatives of regenerative adaptive design and transfer knowledge system capable of the extensive range of applications from microscale to macroscale. The underlying idea proposes orientation on machine learning feedback loop mechanisms and nested coevolutionary loops embedded in an inclusive feedback loop frame, synergistically interfaced with the typologies of monitoring systems and intuitive datasets to problem-solve at the intersection of design, construction, and built environment. This design model can support designers, planners, and city managers in optimizing their decision-making process by relying on precise data-driven feedback in different scales of complex systems, from living bits to ecological living environments.

Large-scale extrusion-based additive manufacturing (AM) has emerged as a potential alternative for construction, addressing the challenges associated with the high carbon footprint of the building industry. Although AM enables the creation of intricate design geometries through controlled material deposition, providing innovative solution strategies for design construction, large-scale 3D printed structures are limited to a single homogeneous material, such as cement or clay, and their functionality is restricted to load-bearing formwork. Although still at a nascent stage for building construction, multimaterial additive manufacturing (MMAM) has emerged as a promising technology for the industry to overcome this limitation and reduce the embodied carbon of 3D printed structures by limiting the use of structural materials through topology optimization strategies. MMAM enables the fabrication of functionally graded materials (FGMs) by controlling the extrusion ratio between two or more distinct materials, resulting in building envelopes with multiple performance characteristics and functions. While research has focused on improving the structural performance of 3D-printed envelopes through MMAM, limited attention has been given to optimizing thermal performance and energy efficiency. An increasing interest in thermal energy storage technologies for buildings using the latent heat storage capacity of microencapsulated phase change materials (mPCMs) is related to the advantages of improving energy efficiency using materials that can absorb, store, and release heat when their temperature changes. To this end, this study proposes an FGM design-to-construction methodology for large-scale structures that optimizes the thermal performance of 3D-printed envelopes by locally tuning the distribution of heterogeneous mixes of clay and mPCMs during the AM process. The results of the digital simulations and physical tests show that the local optimization of mPCM and clay within the wall thickness according to the specific temperature differential can provide annual energy reductions compared with a homogeneously printed envelope without embedded mPCM.

Despite recent advances in 3D printing and additive manufacturing, the main materials in rapid prototyping are derived from finite resources such as petroleum-based plastics. Researchers are developing alternatives to exhaustible and potentially environmentally harmful materials through biomaterials. Mycelium biocomposites are one promising area of inquiry; when mycelium decomposes biomass, it produces a composite biomaterial, which is fully compostable and has beneficial structural and hydrophobic properties. However, mold-based fabrication methods for biocomposites require tooling and limit the possible shapes. We introduce a novel method for directly 3D printing mycelium biocomposites without the need for molds or tooling. Our method comprises three main contributions: Mycofluid, a mycelium-inoculated paste that uses spent coffee grounds, a recycled biomass; Fungibot, a custom hardware system for 3D printing biopastes like Mycofluid; and a method for incubating mycelial growth within fresh 3D prints resulting in mycelium biocomposite parts. We illustrate our contributions through a series of objects showcasing our method and the material qualities of the parts. Notably, we demonstrate how living mycelium can fuse separate prints, enabling complex geometries that are otherwise challenging to 3D print as one part.

This review explores additive manufacturing (AM) strategies across disciplines for designing with responsive biomaterials and presents a vision of how printed responsive biomaterials (PRBs) can be integrated into everyday objects and buildings to enhance environmental and human health. Advancements in biomaterials science, biological materials manufacturing, synthetic biology, biomedical engineering, bio design, and living architecture are ushering in a new era characterized by multisensory interactions within everyday products and built environments. The material systems developed in recent research demonstrate the ability to interact with their environments through biological, chemical, or physical processes, yielding functionalities desirable in daily-use products. These include self-healing, health diagnostics, pathogen neutralization, adjustable stiffness, strain detection, threat visualization, shapeshifting, toxin trapping, stress correction, waste processing, and energy generation. Here we review examples of AM of biobased environmentally interactive materials using biopolymer composites, electrochemical and resistive devices, active molecules, bio sensors, living cells, spores, or cell-free sites, resulting in genetically active, and physical and chemical interactive systems. We highlight their robustness and evaluate their potential for scaling up into designs and architectures on Earth and beyond.