Environmental Impact of Fused Filament Fabrication: What Is Known from Life Cycle Assessment?

This systematic review interrogates the literature to understand what is known about the environmental sustainability of fused filament fabrication, FFF (also known as fused deposition modeling, FDM), based on life cycle assessment (LCA) results. Since substantial energy demand is systematically addressed as one of the main reasons for ecological damage in FFF, mitigation strategies are often based on reducing the printing time (for example, adopting thicker layers) or the embodied energy per part (e.g., by nesting, which means by printing multiple parts in the same job). A key parameter is the infill degree, which can be adjusted to the application requirements while saving printing time/energy and feedstock material. The adoption of electricity from renewable resources is also expected to boost the sustainability of distributed manufacturing through FFF. Meanwhile, bio-based and recycled materials are being investigated as less impactful alternatives to conventional fossil fuel-based thermoplastic filaments.

Hot-Melt Extrusion-Based Dexamethasone-PLGA Implants: Physicochemical, Physicomechanical, and Surface Morphological Properties and In Vitro Release Corrected for Drug Degradation.

Developing bioequivalent (BE) generic products of complex dosage forms like intravitreal implants (IVIs) of corticosteroids such as dexamethasone prepared using hot-melt extrusion (HME), based on biodegradable poly (lactide-co-glycolide) (PLGA) polymers, can be challenging. A better understanding of the relationship between the physicochemical and physicomechanical properties of IVIs and their effect on drug release and ocular bioavailability is crucial to develop novel BE approaches. It is possible that the key physicochemical and physicomechanical properties of IVIs such as drug properties, implant surface roughness, mechanical strength and toughness, and implant erosion could vary for different compositions, resulting in changes in drug release. Therefore, this study investigated the hypothesis that biodegradable ophthalmic dexamethasone-loaded implants with 20% drug and 80% PLGA polymer(s) prepared using single-pass hot-melt extrusion (HME) differ in physicochemical and/or physicomechanical properties and drug release depending on their PLGA polymer composition. Acid end-capped PLGA was mixed with an ester end-capped PLGA to make three formulations: HME-1, HME-2, and HME-3, containing 100%, 80%, and 60% w/w of the acid end-capped PLGA. Further, this study compared the drug release between independent batches of each composition. In vitro release tests (IVRTs) indicated that HME-1 implants can be readily distinguished by their release profiles from HME-2 and HME-3, with the release being similar for HME-2 and HME-3. In the early stages, drug release generally correlated well with polymer composition and implant properties, with the release increasing with PLGA acid content (for day-1 release, R2 = 0.80) and/or elevated surface roughness (for day-1 and day-14 release, R2 ≥ 0.82). Further, implant mechanical strength and toughness correlated inversely with PLGA acid content and day-1 drug release. Drug release from independent batches was similar for each composition. The findings of this project could be helpful for developing generic PLGA polymer-based ocular implant products.

Effectiveness of capsulodesis in ganglion cysts caused by a medial meniscotibial ligament tear and medial meniscus extrusion.

INTRODUCTION AND IMPORTANCE: Meniscotibial ligament (MTL) has received attention as a major meniscus stabilizer. An MTL injury results in instability and extrusion of the meniscus. Cases of knee ganglion cyst formation due to an MTL tear and medial meniscus extrusion (ME) are extremely rare. CASE PRESENTATION: A 42-year-old female Japanese childcare worker presented painful ganglion cysts on the proximal medial side of her left tibia. An MTL tear and medial ME were thought to be involved in the ganglion formation. Joint fluid flowed through the meniscotibial side of the extruded meniscus into the space between the medial collateral ligament and tibia, where the MTL tear acted as a check valve, forming ganglion cysts. Ultrasonography-guided aspiration of the ganglion was attempted, but ganglion cysts recurred within 1 month. We used an open excision for the ganglion cysts, and arthroscopic capsulodesis was performed to repair the MTL and internalize the medial meniscus to block the inflow route from the intra-articular space. CLINICAL DISCUSSION: We performed capsulodesis, which repaired the MTL and internalized the medial meniscus to prevent the recurrence of the ganglion cyst. Three months have passed since the surgery, with no recurrence of knee pain or ganglion cysts, indicating good short-term results. CONCLUSIONS: We encountered a rare case of ganglion cyst formation in the knee joint due to MTL tear and medial ME. Arthroscopic MTL repair and internalization of the meniscus by capsulodesis were effective in treating the ganglion cysts.

Impact of hydroxypropylation coupled with extrusion treatment on the morphological, structural, and rheological properties of sorghum and corn starch.

The purpose of the present study to prepare hydroxypropyl derivatives (HP) instant (partially cold-water swell-able) starches via extrusion technique (Ex) from sorghum and corn. The native and hydroxypropylated (at propylene level 5 % and 12 %) starch extrudates were evaluated for functional, structural, thermal and rheological properties. The development of extrudates provides ease to industries as they are easily soluble in aqueous mediums and does not require any prior heating. The degree of substitution (DS) for all extrudates varied between 0.0083 and 0.1530 which is under limit and save to consume. The X-ray diffraction (XRD) analysis revealed that all extrudates exhibited V-type pattern while the intensity of peaks increased due to hydroxypropylation. The starch extrudates showed gel-like behavior since storage modulus (G') was greater than loss modulus (G″). Non-Newtonian shear thinning behavior was observed for all extrudates. At lower temperature, HP-Ex at higher substitution level (12 %) demonstrated higher complex viscosity than native and low-substituted extrudates. Creep recovery of HP-Ex dispersion was more pronounced than native extrudates suggesting elastic nature of sorghum and corn starch extrudates. The differential scanning calorimetry (DSC) results revealed that HP-Ex were observed to gelatinize at lower temperatures and needed lower enthalpy of gelatinization (ΔHgel) because of their weakened structure after modification.

Material extrusion 3D-printing technology: A new strategy for constructing water-soluble, high-dose, sustained-release drug formulations.

The advantage of low-temperature forming through direct ink writing (DIW) 3D printing is becoming a strategy for the construction of innovative drug delivery systems (DDSs). Optimization of the complex formulation, including factors such as the printing ink, presence of solvents, and potential low mechanical strength, are challenges during process development. This study presents an application of DIW to fabricate water-soluble, high-dose, and sustained-release DDSs. Utilizing poorly compressible metformin hydrochloride as a model drug, a core-shell delivery system was developed, featuring a core composed of 96 % drug powder and 4 % binder, with a shell structure serving as a drug-release barrier. This design aligns with the sustained-release profile of traditional processes, achieving a 25.8 % reduction in volume and enhanced mechanical strength. The strategy facilitates sustained release of high-dose water-soluble formulations for over 12 h, potentially improving patient compliance by reducing formulation size. Process optimization and multi-batch flexibility were also explored in this study. Our findings provide a valuable reference for the development of innovative DDSs and 3D-printed drugs.

Early Evidence of Post-Mortem Fetal Extrusion in Equids: A Case from the Western Zhou Period (1045-771 BC) Site of Yaoheyuan in Northwestern China.

Post-mortem fetal extrusion, also known as "coffin birth", refers to the phenomenon where a fetus is pushed out of a deceased female due to pressure from decomposing gas in the abdominal cavity. While post-mortem fetal extrusion has been documented in humans at several archaeological sites, there are few reports of it occurring in non-human animals. In this study, we present a case of post-mortem fetal extrusion in equids observed in a chariot-horse pit (CMK2) at the Western Zhou period site of Yaoheyuan in northwestern China, dating to the early first millennium BC. This specific pit, one of four excavated at the site, contained at least 29 horses and 3 wooden chariots. Most of these horses were young adults aged between 4 and 12 years. Out of the 22 horses with sex estimates, 21 were males. Among these individuals, one adult female horse (Horse 6) and one infantile horse (Horse 10) were of particular importance. Based on the age-at-death, sex, and head orientation of the two individuals, alongside their spatial relationships, it is highly likely that Horse 6 was the fetus of Horse 10 and was extruded in the pit. According to the parturition stage of Horse 10, Horse 6 was likely interred in CMK2 in late spring or early summer of the year, during which the relatively high temperature may have generated gas that led to the extrusion of the fetus. Although the specific reason for the inclusion of a pregnant mare in a chariot-horse pit at Yaoheyuan remains a topic for future research, this case marks the first report of post-mortem fetal extrusion in archaeological horses. The findings offer insights into the timing of horse interment as part of ritual practices among the settled elites during the Bronze Age in China and provide valuable reference data for contemporary equine veterinary science.

Ingredient Functionality of Soy, Chickpea, and Pea Protein before and after Dry Heat Pretreatment and Low Moisture Extrusion.

This study investigates the impact of dry heat pretreatment on the functionality of soy, chickpea, and pea protein ingredients for use in texturized vegetable protein (TVP) production via low moisture extrusion. The protein powders were heat-treated at temperatures ranging from 80 °C to 160 °C to modulate the extent of protein denaturation and assess their effects on RVA pasting behavior, water absorption capacity (WAC), and color attributes. The results indicate that the pretreatment temperature significantly influenced the proteins' functional properties, with an optimal temperature of 120 °C enhancing pasting properties and maintaining WAC, while a higher pretreatment temperature of 160 °C led to diminished ingredient functionality. Different protein sources exhibited distinct responses to heat pretreatment. The subsequent extrusion processing revealed significant changes in extrudate density and color, with increased density and darkness observed at higher pretreatment temperatures. This research provides insights into the interplay between protein sources, pretreatment conditions, and extrusion outcomes, highlighting the importance of controlled protein denaturation for developing high-quality, plant-based meat analogues. The findings have broad implications for the optimization of meat analogue manufacturing, with the aim of enhancing the sensory experience and sustainability of plant-based foods.

Possibility of Isolated Mung Bean Protein as a Main Raw Material in the Production of an Extruded High-Moisture Meat Analog.

As consumer demand for meat analogs continues to grow, various plant proteins are being explored for their production. This study uses isolated mung bean protein (IMBP) to replace isolated soy protein (ISP), investigating the effects of IMBP content (0%, 10%, 20%, 30%, 40%, and 50%) on the physicochemical and textural properties of high-moisture meat analogs (HMMAs) and exploring the potential of IMBP in the development and production of meat analogs. The results show that IMBP can bind water and cause protein denaturation, thus requiring more time and higher temperatures to be formed compared to HMMAs without IMBP. Additionally, increasing the IMBP content improves the gelling ability, thereby increasing the input of specific mechanical energy. As the IMBP content increases, the fibrous structure of the HMMA also increases. When the IMBP content reaches 40-50%, the most meat-like fibrous structure is observed. The water-holding capacity, water absorption capacity, springiness, and cohesiveness are negatively correlated with the IMBP content, while the oil absorption capacity is positively correlated with it. The integrity index and nitrogen solubility index show opposite trends with the increase in the IMBP content. When the IMBP content is 50%, the springiness and chewiness are the lowest, and the cutting strength is also the lowest, but the sample has a rich fibrous content, indicating that the HMMA with 50% IMBP content is soft and juicy. In conclusion, IMBP has the potential to be a substitute for ISP in the production of HMMAs.

A Comprehensive Review on Harnessing Soy Proteins in the Manufacture of Healthy Foods through Extrusion.

The global development of livestock production systems, accelerated by the growing demand for animal products, has greatly contributed to land-use change, greenhouse gas emissions, and pollution of the local environment. Further, excessive consumption of animal products has been linked with cardiovascular diseases, digestive system diseases, diabetes, and cancer. On the other hand, snacks, pasta, and bread available on the market are made from wheat, fat, salt, and sugar, which contribute to the risk of cardiovascular diseases. To counter these issues, a range of plant protein-based food products have been developed using different processing techniques, such as extrusion. Given the easy scalability, low cost of extrusion technology, and health benefits of soy proteins, this review focuses on the extrusion of soy protein and the potential application of soy protein-based extrudates in the manufacture of healthy, nutritious, and sustainable meat analogs, snacks, pasta products, and breakfast cereals. This review discusses the addition of soy protein to reformulate hypercaloric foods through extrusion technology. It also explores physical and chemical changes of soy proteins/soy protein blends during low and high moisture extrusion. Hydrogen bonds, disulfide bonds, and hydrophobic interactions influence the properties of the extrudates. Adding soy protein to snacks, pasta, breakfast cereals, and meat analogs affects their nutritional value, physicochemical properties, and sensory characteristics. The use of soy proteins in the production of low-calorie food could be an excellent opportunity for the future development of the soybean processing industry.

Effects of Different Soybean and Coconut Oil Additions on the Physicochemical and Sensory Properties of Soy Protein-Wheat Protein Mixture Subjected to High-Moisture Extrusion.

A protein mixture was prepared using a blend of soybean protein isolate, soybean protein concentrate, and wheat protein through high-moisture extrusion. This study investigated the effects of soybean oil/coconut oil additions (2%, 5%, and 8%) on the physiochemical properties of a soy protein-wheat protein mixture subjected to high-moisture extrusion. The protein extrudates underwent assessment for textural properties, fiber degree, sensory evaluation, microstructure, protein solubility, and protein secondary structure. The findings indicated that plant oils significantly reduced the hardness, springiness, and chewiness of the extrudates, and 5% plant oil significantly increased the fiber degree of the extrudates. In addition, the highest fiber degree and sensory evaluation score were achieved with 5% coconut oil. Observation of the macro- and microstructure indicated that the presence of unsaturated fatty acids in soybean oil did not benefit the improvement of the fibrous structure of protein extrudates during high-moisture extrusion processing. SDS-PAGE and FTIR results revealed that coconut oil, rich in saturated fatty acids, caused the clustering of medium- and low-molecular-weight subunits in texturized protein. Additionally, coconut oil elevated the ratio of 11S protein subunits containing sulfur-based amino acids and facilitated a shift from ß-turn to ß-sheet. The inclusion of plant oils increased the development of hydrogen and disulfide bonds, resulting in a denser, fibrous structure. DSC demonstrated that plant oils reduced the thermal stability of the texturized proteins but enhanced the order of protein structure.

Impact of Sourdough from a Commercial Starter Culture on Quality Characteristics and Shelf Life of Gluten-Free Rice Breads Supplemented with Chickpea Flour.

This study aimed to develop a novel gluten-free bread using a rice/chickpea flour-based sourdough, fermented by a commercial starter culture, to improve the quality characteristics and shelf life of this product. The effects of sourdough incorporation, chickpea flour content (6.5 and 10.0%), and added water level (80-110%) on batter rheology and bread quality were investigated; bread textural characteristics upon storage (0-2 days) were also monitored. The level of added water was the primary factor influencing batter rheology, as evaluated by the back extrusion test. Sourdough incorporation decreased the pH and increased the acidity of batters and breads. The inclusion of sourdough, the water level, and the storage time affected the moisture and texture parameters of the bread crumb. Sourdough incorporation into bread formulations decreased crumb hardness and staling rate and increased loaf specific volume. Moreover, intermediate water (90 and 100%) and high chickpea (10%) levels in the batters increased loaf specific volumes and crust redness, respectively. Sensory analysis revealed that sourdough-enriched breads were preferred by the assessors concerning general appearance and crumb texture. Overall, bread formulations with the incorporation of sourdough, at a 90% level of added water in the batter mixtures, exhibited the most desirable characteristics according to both instrumental and sensory analyses.

Achieving High Strength-Ductility Synergy in Low-Alloyed Mg-Li-Er Extrusion Alloys via Tailoring Bimodal-Grained Structure.

Low-alloyed Mg-Li-Er alloys were developed in this study and a bimodal-grained structure was obtained by varying the trace Er content and extrusion temperature. The alloys displayed a good strength-ductility synergy, i.e., a tensile yield strength (TYS) of 270 MPa and an elongation (EL) of 19.1%. Microstructural characterization revealed that the formation of numerous submicron Mg24Er5 particles favored a high density of low-angle grain boundaries (LAGBs) inside the deformed grains and inhibited dynamic recrystallization (DRX). The resultant coarse unDRXed grains with a strong basal texture and considerable LAGBs, together with the fine DRXed grains, contributed to the high strength-ductility synergy.

The Stamping Method Utilizing a Double-Trough Die in Microforming to Enhance Formability.

Currently, the field of microgear manufacturing faces various processing challenges, particularly in terms of size reduction; these challenges increase the complexity and costs of manufacturing. In this study, a technique for microgear manufacturing is aimed at reducing subsequent processing steps and enhancing material utilization. This technique involves the use of trough dies with extrusion-cutting processing, which enables workpieces to undergo forming in a negative clearance state, thus reducing subsequent processing time for micro products. We conducted finite element simulations using microgear dies, measuring stress, velocity, and flow during the forming process of four types of dies-flat, internal-trough, external-trough, and double-trough dies. The results indicated that the buffering effect of the troughs reduced the rate of increase in the material's internal stress. In the cavity, the material experiences a significant increase in hydrostatic pressure, leading to the formation of a "hydrostatic pressure wall". This pressure barrier imposes substantial constraints on the flow of the material during dynamic processes, making it difficult for the material to move into the remaining areas. This effectively enhances the blockage of material flow, demonstrating the critical role of hydrostatic pressure in controlling material distribution and movement. In addition, combining the characteristics of both into a double-trough die enhances the overall stability of forming velocity, reduces forming load and energy consumption, and maximizes material utilization. Results further revealed that microgears manufactured using double-trough dies exhibited defect-free surfaces, with a dimensional error of less than 5 µm and tolerances ranging from IT5 to IT6. Overall, this study offers new insights into the traditional field of microgear manufacturing, highlighting potential solutions for the challenges encountered in current microstamping processes.

The Impact of Orthodontic Extrusion on Keratinized Gingiva.

Background and Objectives: The key factor that enables osteoblastic activity and the formation of new bone, as well as gingiva, during orthodontic tooth extrusion (OE) is the periodontal ligament. The reaction of periodontal tissues associated with changes in the gingiva is a part of orthodontic tooth displacement. The aim of this study was to examine the effect of OE on the width of the zone of the keratinized and attached gingiva, the position of the mucogingival junction, and the height of the interdental papillae in the region where the OE was performed as well as in the adjacent region. Materials and Methods: This research included 28 adult patients (both orthodontically treated and untreated). The treated group included 15 patients, in whom orthodontic extrusion of the upper or lower frontal teeth was indicated and performed. The untreated group included 13 patients, with no previous or undergoing orthodontic treatment. Patients with periodontal disease and periodontal pockets in the frontal region and patients allergic to iodine were excluded from the study. Gingivomorphometric measurements were performed on two occasions in three groups of teeth (24 extruded and 30 agonist teeth in the treated patients; 66 teeth in the untreated patients). Statistical analysis of the obtained data was performed using the software package SPSS version 26.0. Results: Orthodontic extrusion induced changes in the position of the mucogingival line and an increase in the width of the keratinized gingiva. There were no statistically significant effects on the depth of the gingival sulcus, the attached gingiva width, or the height of the interdental papillae. Conclusions: Orthodontic tooth extrusion has an effect on the periodontium in the observed region. Vertical orthodontic force, directed towards the coronal plane, affects the surrounding soft oral tissues.

Effects of high gravity on properties of parts fabricated using material extrusion system by additive manufacturing.

Additive manufacturing (AM) has gained significant attention in recent years owing to its ability to fabricate intricate shapes and structures that are often challenging or unattainable using conventional manufacturing techniques. This high-quality development trend entails higher requirements for the structural design of 3D printers. In this study, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) filaments were fed through a heated extrusion nozzle, which melted the material and deposited it onto a build platform. This study's objectives are high-gravitational material extrusion (HG-MEX) systems development, analyzing the high gravity influences on the flow behavior of materials during extrusion, and understanding the effects of gravitational on material flow and overall extrusion performance. HG-MEX systems have great potential for addressing various challenges in additive manufacturing, such as precise manufacturing. The highlight of the progress is that we developed an HG-MEX system and applied surface science to material extrusion in different gravity. We established a system and obtained results on different gravity, we analyzed the analogy between different gravity phenomena. We analyzed the interplay between the behavior of the fabricated parts and gravity. We analyzed high gravity effects on extrusion processes. The results confirmed the characteristics and feasibility of the developed system. The results suggest that a material extrusion line operating under 15 G conditions resulted in better printing quality compared to one operating under 1 G conditions. This observation implies that high gravity had a positive effect on the extrusion process, leading to improved material extrusion performance.

High-yield nanovesicles extruded from dental follicle stem cells promote the regeneration of periodontal tissues as an alternative of exosomes.

AIM: To identify an optimized strategy for the large-scale production of nanovesicles (NVs) that preserve the biological properties of exosomes (EXOs) for use in periodontal regeneration. MATERIALS AND METHODS: NVs from dental follicle stem cells (DFSCs) were prepared through extrusion, and EXOs from DFSCs were isolated. The yield of both extruded NVs (eNVs) and EXOs were quantified through protein concentration and particle number analyses. Their pro-migration, pro-proliferation and pro-osteogenesis capacities were compared subsequently in vitro. Additionally, proteomics analysis was conducted. To further evaluate the periodontal regeneration potential of eNVs and EXOs, they were incorporated into collagen sponges and transplanted into periodontal defects in rats. In vivo imaging and H&E staining were utilized to verify their biodistribution and safety. Micro-Computed Tomography analysis and histological staining were performed to examine the regeneration of periodontal tissues. RESULTS: The yield of eNVs was nearly 40 times higher than that of EXOs. Interestingly, in vitro experiments indicated that the pro-migration and pro-proliferation abilities of eNVs were superior, and the pro-osteogenesis potential was comparable to EXOs. More importantly, eNVs exhibited periodontal regenerative potential similar to that of EXOs. CONCLUSIONS: Extrusion has proven to be an efficient method for generating numerous eNVs with the potential to replace EXOs in periodontal regeneration.

Tympanostomy Tubes Under Local Versus General Anesthesia for Children: A Prospective Long-Term Study.

OBJECTIVES: Tympanostomy tube insertion (TTI) under local anesthesia (LA) is gaining popularity but literature comparing long-term outcomes for children undergoing TTI under LA versus general anesthesia (GA) is limited. This study compares the long-term quality of life (QoL) between LA and GA in children undergoing TTI. Secondary objectives included long-term behavioral changes, parental satisfaction, tube durability, and postoperative complications. METHODS: We prospectively followed children aged under 6 who underwent TTI, under LA or GA, 2 years prior. We assessed QoL using validated scales (OM6, PedsQL), analyzed behavioral changes and parental satisfaction through qualitative scales, and retrieved data on tube durability and non-immediate complications. RESULTS: A total of 84 children (LA = 42; GA = 42) had complete data and a minimum of 1 year of follow-up. Demographic data were similar, except for younger patients in the LA group (1.4 vs. 1.9 years, p = 0.02). LA group exhibited increased fear of health care professionals following TTI (LA: Likert scale 2.1/5, GA: 1.5/5, p = 0.04). Tube retention rate was shorter in the LA group (at 15 months: GA:72%, LA:50%, p = 0.039). Two years post-TTI, there were no differences regarding QoL (OM-6 score; LA: 15.2/100, GA: 21.4/100, p = 0.18, and PedsQL score; LA: 84.3/100, GA: 83.8/100, p = 0.90), parental satisfaction with anesthesia (GA: 4.5/5, LA: 4.6/5, p = 0.56), and postoperative complications (GA: 3/42, LA: 7/42, p = 0.18). CONCLUSIONS: TTI under LA in children is associated with an increased fear of health care professionals and shorter functionality of tympanostomy tubes as compared to GA. No difference was observed in long-term QoL, parental satisfaction, and complications rate. LEVEL OF EVIDENCE: Level 3 Laryngoscope, 2024.

Pneumatic extrusion bioprinting-based high throughput fabrication of a melanoma 3D cell culture model for anti-cancer drug screening.

The high incidence of malignant melanoma highlights the need for in vitro models that accurately represent the tumour microenvironment, enabling developments in melanoma therapy and drug screening. Despite several advancements in 3D cell culture models, appropriate melanoma models for evaluating drug efficacy are still in high demand. The 3D pneumatic extrusion-based bioprinting technology offers numerous benefits, including the ability to achieve high-throughput capabilities. However, there is a lack of research that combines pneumatic extrusion-based bioprinting with analytical assays to enable efficient drug screening in 3D melanoma models. To address this gap, this study developed a simple and highly reproducible approach to fabricate a 3D A375 melanoma cell culture model using the pneumatic extrusion-based bioprinting technology. To optimise this method, the bioprinting parameters for producing 3D cell cultures in a 96-well plate were adjusted to improve reproducibility while maintaining the desired droplet size and a cell viability of 92.13± 6.02%. The cross-linking method was optimised by evaluating cell viability and proliferation of the 3D bioprinted cells in three different concentrations of calcium chloride. The lower concentration of 50 mM resulted in higher cell viability and increased cell proliferation after 9 days of incubation. The A375 cells exhibited a steadier proliferation rate in the 3D bioprinted cell cultures, and tended to aggregate into spheroids, whereas the 2D cell cultures generally formed monolayered cell sheets. In addition, we evaluated the drug responses of four different anti-cancer drugs on the A375 cells in both the 2D and 3D cell cultures. The 3D cell cultures exhibited higher levels of drug resistance in all four tested anti-cancer drugs. This method presents a simple and cost-effective method of producing and analysing 3D cell culture models that do not add additional complexity to current assays and shows considerable potential for advancing 3D cell culture models' drug efficacy evaluations.

Bioprinting of Synthetic Cell-like Lipid Vesicles to Augment the Functionality of Tissues after Manufacturing.

Bioprinting is an automated bioassembly method that enables the formation of human tissue-like constructs to restore or replace damaged tissues. Regardless of the employed bioprinting method, cells undergo mechanical stress that can impact their survival and function postprinting. In this study, we investigate the use of a synthetic cell-like unit, giant unilamellar vesicles (GUVs), as adjuvants of the cellular function of human cells postprinting, or in future as the complete replacement of human cells. We analyzed the impact of two nozzle-based bioprinting methods (drop-on-demand and extrusion bioprinting) on the structure, stability, and function of GUVs. We showed that over 65% of the GUVs remain intact when printing at 0.5 bar, demonstrating the potential of using GUVs as a synthetic cell source. We further increased the stability of GUVs in a cell culture medium by introducing polyethylene glycol (PEG) into the GUV lipid membrane. The presence of PEG, however, diminished the structural properties of GUVs postprinting, and reduced the interaction of GUVs with human cells. Although the design of PEG-GUVs can still be modified in future studies for better cell-GUV interactions, we demonstrated that GUVs are functional postprinting. Chlorin e6-PEG-GUVs loaded with a fluorescent dye were bioprinted, and they released the dye postprinting only upon illumination. This is a new strategy to deliver carriers, such as growth factors, drugs, nutrients, or gases, inside large bioprinted specimens on a millimeter to centimeter scale. Overall, we showed that printed GUVs can augment the functionality of manufactured human tissues.

Advancing molecular understanding in high moisture extrusion for plant-based meat analogs: Challenges and perspectives.

In recent years, meat analogs based on plant proteins have received increasing attention. However, the process of high moisture extrusion (HME), the method for their preparation, has not been thoroughly explored, particularly in terms of elucidating the complex interactions that occur during extrusion, which remain challenging. These interactions arise from the various ingredients added during HME, including proteins, starches, edible gums, dietary fibers, lipids, and enzymes. These ingredients undergo intricate conformational changes and interactions under extreme conditions of high temperature, pressure, and shear, ultimately forming the fibrous structure of meat analogs. This review offers a overview of these ingredients and the molecular interaction changes they undergo during the extrusion process. Additionally, it delves into the major molecular interactions such as disulfide bonding, hydrogen bonding, and hydrophobic interactions, providing detailed insights into each.