Types Of Filaments Research Articles

Altering the mechanical properties of self-assembled filaments through engineering of EspA bacterial protein.

Protein-based biomaterials are in high demand due to their high biocompatibility, non-toxicity, and biodegradability. In this study, we explore the bacterial E. coli secreted protein A (EspA), which self-assembles into long extracellular filaments, as a potential building block for new protein-based biomaterials. We investigated the morphological and mechanical properties of EspA filaments and how protein engineering can modify them. Our study include three types of filaments: natural EspA filaments, full-length recombinant EspA filaments, and truncated recombinant EspA filaments lacking a third of the original codon region. The recombinant EspA proteins formed curly, thin filaments with higher longitudinal elasticity (shorter persistence length) compared to the natural, linear filaments. Additionally, the recombinant filaments had a radial elastic modulus about an order of magnitude lower than the natural filaments. The truncated recombinant filaments had a higher radial modulus than the full-length ones, and unlike the purely elastic natural filaments, recombinant filaments were less compliant with the applied force that penetrated them. These differences underscore the potential to modulate EspA filament properties through protein sequence mutations. Our findings suggest EspA as a fundamental element for developing a new biomaterial with a hierarchical structure, enabling the fabrication of macroscopic substances from self-assembled EspA-modulated filaments.

Transient interactions between the fuzzy coat and the cross-β core of brain-derived Aβ42 filaments.

Several human disorders, including Alzheimer's disease (AD), are characterized by the aberrant formation of amyloid fibrils. In many cases, the amyloid core is flanked by disordered regions, known as fuzzy coat. The structural properties of fuzzy coats, and their interactions with their environments, however, have not been fully described to date. Here, we generate conformational ensembles of two brain-derived amyloid filaments of Aβ42, corresponding respectively to the familial and sporadic forms of AD. Our approach, called metadynamic electron microscopy metainference (MEMMI), provides a characterization of the transient interactions between the fuzzy coat and the cross-β core of the filaments. These calculations indicate that the familial AD filaments are less soluble than the sporadic AD filaments, and that the fuzzy coat contributes to solubilizing both types of filament. These results illustrate how the metainference approach can help analyze cryo-EM maps for the characterization of the properties of amyloid fibrils.

Vimentin Intermediate Filaments Maintain Membrane Potential of Mitochondria in Growing Neurites.

Neural precursor cells contain two types of intermediate filaments (IFs): neurofilaments consisting of three IV type proteins and vimentin belonging to the type III IF proteins that disappear at the later stages of differentiation. The involvement of vimentin in neurogenesis was demonstrated earlier; however, the role of its temporary expression in neurons is not clear. We showed that the vimentin IFs that interacted with mitochondria maintained their membrane potential at the appropriate level, and thus, ensured their proper function. We examined the dependence of the mitochondrial membrane potential on the expression of vimentin in a CAD catecholaminergic neuronal cell line that was actively dividing in full culture media but stopped growing and started developing neurites when the serum was removed. Using the CRISPR Cas9 system to knock out the vimentin gene in these cells, we investigated the impact of this on the mitochondrial membrane potential. Our data show that the deletion of the vimentin IFs led to a decrease in the level of the mitochondrial potential. When the vimentin network in these cells was reconstituted by transfection with a plasmid that encoded human protein, the level of the potential was restored. Interestingly, mutated vimentin with a disrupted mitochondria-binding site had no such effect. Our data point to vimentin as a possible target in some neurological pathologies.

Evaluation of wash colour strength of a printed garment with flexible filaments on 3D printers

The research aims to evaluate the solidity of the washing colour of a garment printed with flexible filaments on 3D printers. Three groups of factors have been selected: Anet A8 and M3D Crane Quad printer, temperature (49° and 71°C) and flexible filaments TPE (thermoplastic elastomer) and TPU (polyurethane thermoplastic), framed in the factorial design, type applied of 10 units per combination of factors in a total of 80 sampling units, using Girowah equipment according to the technical standard AATCC TM61-2020. The results show that the printer factors Anet A8 and M3D Crane Quad with the CIELab and CMC (2:1) discolouration system exceed 50% in both the tolerances of the value 1. About the temperature factor (49° and 71°C), which exhibits a discolouration of 1.06 in CIE94 and 1.36 in CMC, it is determined that the combination with better resistance to discolouration of solidity at washing (CIE94 - 49°C) compared to CMC (2:1) better establishes the visual and technical concordance of the solidity of colour. As regards flexible filament types: TPE and TPU, the results show us that the colour tolerance assessments (CIELab CIE94) and (CMC (2,1)) prove that the TPE filament has greater resistance to the discoloration of the 3D-printed garment at different temperatures. In conclusion, the solidity of colour washing in a printed garment with flexible filaments in a 3D printer causes discolouration by the minimum, be it the factors of printer type, filament, and temperature. There is a need for analysis with other values and it remains open to other research.

DGAE(297-391) Tau Fragment Promotes Formation of Chronic Traumatic Encephalopathy-Like Tau Filaments.

The microtubule-associated protein tau forms disease-specific filamentous aggregates in several different neurodegenerative diseases. In order to understand how tau undergoes misfolding into a specific filament type and to control this process for drug development purposes, it is crucial to study in vitro tau aggregation methods and investigate the structures of the obtained filaments at the atomic level. Here, we used the tau fragment dGAE, which aggregates spontaneously, to seed the formation of full-length tau filaments. The structures of dGAE and full-length tau filaments were investigated by magic-angle spinning (MAS) solid-state NMR, showing that dGAE allows propagation of a chronic traumatic encephalopathy (CTE)-like fold to the full-length tau. The obtained filaments efficiently seeded tau aggregation in HEK293T cells. This work demonstrates that in vitro preparation of disease-specific types of full-length tau filaments is feasible.

Two Forms of Thick Filament in the Flight Muscle of Drosophila melanogaster.

Invertebrate striated muscle myosin filaments are highly variable in structure. The best characterized myosin filaments are those found in insect indirect flight muscle (IFM) in which the flight-powering muscles are not attached directly to the wings. Four insect orders, Hemiptera, Diptera, Hymenoptera, and Coleoptera, have evolved IFM. IFM thick filaments from the first three orders have highly similar myosin arrangements but differ significantly among their non-myosin proteins. The cryo-electron microscopy of isolated IFM myosin filaments from the Dipteran Drosophila melanogaster described here revealed the coexistence of two distinct filament types, one presenting a tubular backbone like in previous work and the other a solid backbone. Inside an annulus of myosin tails, tubular filaments show no noticeable densities; solid filaments show four paired paramyosin densities. Both myosin heads of the tubular filaments are disordered; solid filaments have one completely and one partially immobilized head. Tubular filaments have the protein stretchin-klp on their surface; solid filaments do not. Two proteins, flightin and myofilin, are identifiable in all the IFM filaments previously determined. In Drosophila, flightin assumes two conformations, being compact in solid filaments and extended in tubular filaments. Nearly identical solid filaments occur in the large water bug Lethocerus indicus, which flies infrequently. The Drosophila tubular filaments occur in younger flies, and the solid filaments appear in older flies, which fly less frequently if at all, suggesting that the solid filament form is correlated with infrequent muscle use. We suggest that the solid form is designed to conserve ATP when the muscle is not in active use.

Preparation of continuous carbon fiber reinforced PA6 prepreg filaments with high fiber volume fraction

High-performance continuous carbon fiber prepreg filaments have been a research hotspot in the field of additive manufacturing in recent years, and are considered to be an effective option for improving the mechanical strength of thermoplastic composite parts. However, the effect of fiber volume fraction on the microstructure and tensile properties of 3D printed prepreg filaments remains miss. Therefore, this study selected suitable impregnation processes and materials to prepare prepreg filaments with different fiber volume fraction and investigated their mechanical properties and microscopic morphologies. The results show that the increase of fiber volume fraction effectively promoted the interface bonding between fiber and resin, and increased capacity for load transfer. When the fiber volume fraction was 54.0 %, the tensile strength of the prepreg filaments and specimens reached 1977 MPa and 334 MPa, respectively. This study can provide a process optimization strategy for the preparation of more types of continuous fiber prepreg filaments with high fiber volume fraction, as well as a data reference for the preparation of high-performance 3D-printed thermoplastic composites.

3D Printing and Biodegradable Polymers

Abstract 3D printing technology has a wide range of applications in many industries, including automotive, aerospace, biomedical, electronics and packaging, requiring different types of filaments to be used in producing 3D printed objects. The most commonly used materials are metals, ceramics, composites and plastics of which the latter are most available. Since it is necessary to reduce pollution caused by waste from conventional petroleum-based plastics, biodegradable polymers made from renewable resources or produced synthetically have gained in importance recently. Polylactic acid, poly(butylene succinate), thermoplastic starch, poly(butylene adipate co-terephthalate) and polycaprolactone are well-known representatives of this group of materials. They possess desirable properties for 3D printing which make them promising materials in many areas of applications.

Repetitive recycling effects on mechanical characteristics of poly‐lactic acid and PLA/spent coffee grounds composite used for 3D printing filament

AbstractDue to its biodegradability, biocompatibility, and mechanical properties, poly‐lactic acid (PLA) is a leading biomaterial for numerous applications, especially for fused deposition modeling and fused filament fabrication. Nonetheless, the absence of a comprehensive recycling strategy may emerge as a significant source of plastic pollution in the future. Indeed, the polymer undergoes deterioration during melt recycling, resulting in a decrease in some mechanical properties that can compromise recyclability. To improve the properties of recycled PLA, the utilization of organic fillers coming from renewable materials can be considered as a sustainable solution. The objective of this work is then to evaluate the effect of recycling (reprocessing) on a virgin raw material as well as on biocomposites based on spent coffee grounds (incorporating 5% of spend coffee grounds in weight). The different types of filaments are extruded and re‐extruded and characterized under tensile, melt flow index, and hardness tests. The results show that the increase in the number of extrusions whether for virgin PLA or the composite contributes to the diameter fluctuation. Regarding the tensile properties, the rise in the frequency of recycling shows a weakness in the tensile strength and the elongation at break. On the other hand, Young's modulus values exhibit fluctuations. Concerning the addition of the spent coffee grounds filler, no major enhancement is observed in the tensile strength and the elongation at break, which is attributed to the poor adhesion between the matrix and the filler. The recycling process affects the hardness values of PLA, leading to an increase in these values, as well as those of the composite, which can be associated with the increased crystallinity caused by the recycling process and the SCG incorporation.Highlights Recycling and reusability strategy for poly‐lactic acid (PLA) and PLA/spent coffee grounds (SCG) filaments. Assessment of recycling effects on PLA and PLA/SCG. Mechanical characterization through tensile and hardness testing.

Cell motility, cytoskeleton, and motor proteins-21st IUPAB Congress session commentary.

The cytoskeleton is the major mechanical unit of the cell and is essential for cellular processes such as motility, division, and contraction. It consists of three types of biopolymers-actin filaments, microtubules, and intermediate filaments-along with passive cross-linkers and active motor proteins. This composite biological material determines the enormous viscoelastic adaptability of cells to varying mechanical demands. In the session entitled "Cell Motility, Cytoskeleton, and Motor Proteins" at the IUPAB 2024 Congress in Kyoto, Japan, we elucidated specific examples of cell mechanics and dynamics from a physical point of view, including different length scales from molecular to cellular, as well as in vitro reconstituted systems and cellular systems.

IrOnTex: Using Ironable 3D Printed Objects to Fabricate and Prototype Customizable Interactive Textiles

In this paper, we propose IrOnTex, an approach to design, fabricate, and prototype customizable interactive textiles by ironing 3D printed elements directly onto fabrics. Our method incorporates multiple filament types to demonstrate functionalities such as electrical conductivity, sensing, and thermo- and photo-sensitivity for interactive applications. Additionally, we integrate a tiling-like fragmented design to improve stretchability and flexibility to match the mechanical behavior of textiles in our 3D printed elements. We characterized the iron-on process through technical evaluations, which showed the durability and reversibility of the approach. We also suggested baseline parameters for prototyping and methods to enhance the functionality of certain materials. The empirical results from the studies were used to develop a design tool to assist the design process. A user study with 10 participants revealed the helpfulness of the tool. To demonstrate the capabilities of the approach, we show a set of example interactive applications. We envision the proposed approach will enable designers to rapidly prototype interactive textile applications.

Architecture influence on acoustic performance, EMI shielding, electrical and thermal, properties of 3D printed PLA/graphite/molybdenum disulfide composites

Fused Filament Fabrication (FFF) is one of the most emerging techniques nowadays. Affordable, easy to use, economical, for a broad audience − from specialists to home users. These are only several of its advantages. A disadvantage is the limited number of available filament types, especially those with high performance. Therefore, the aim of the work was to investigate the properties of custom–made filament printouts based on polylactic (PLA), graphite (G) and molybdenum disulfide (MoS2).This work looked at structural and thermal analysis, acoustic performance, EMI shielding, and electrical and thermal properties, including thermal conductivity and heat diffusivity. The following were considered during the study: type of printing architecture, infill density, and filament formulations. Among the best values, which were obtained for the highest loaded sample based on 15 wt% graphite and 2 wt% MoS2 (G15/M2), where EMI shielding effectiveness surpassed SETOT ∼ 17 dB (per 1 mm sample thickness), electrical conductivity remained at a low level. It exceeded σ ∼ 0.2 S/m; thermal conductivity was slightly over κ ∼ 0.4 W/mK, and heat diffusivity was almost α ∼ 0.4 mm2/s.This work is the first step in designing high-performance materials dedicated to advanced applications based on the FFF technique.

Spontaneous Calcium Transients Recorded from Striatal Astrocytes in a Preclinical Model of Autism

Autism spectrum disorder (ASD) is known as a group of neurodevelopmental conditions including stereotyped and repetitive behaviors, besides social and sensorimotor deficits. Anatomical and functional evidence indicates atypical maturation of the striatum. Astrocytes regulate the maturation and plasticity of synaptic circuits, and impaired calcium signaling is associated with repetitive behaviors and atypical social interaction. Spontaneous calcium transients (SCT) recorded in the striatal astrocytes of the rat were investigated in the preclinical model of ASD by prenatal exposure to valproic acid (VPA). Our results showed sensorimotor delay, augmented glial fibrillary acidic protein -a typical intermediate filament protein expressed by astrocytes- and diminished expression of GABAA-ρ3 through development, and increased frequency of SCT with a reduced latency that resulted in a diminished amplitude in the VPA model. The convulsant picrotoxin, a GABAA (γ-aminobutyric acid type A) receptor antagonist, reduced the frequency of SCT in both experimental groups but rescued this parameter to control levels in the preclinical ASD model. The amplitude and latency of SCT were decreased by picrotoxin in both experimental groups. Nipecotic acid, a GABA uptake inhibitor, reduced the mean amplitude only for the control group. Nevertheless, nipecotic acid increased the frequency but diminished the latency in both experimental groups. Thus, we conclude that striatal astrocytes exhibit SCT modulated by GABAA-mediated signaling, and prenatal exposure to VPA disturbs this tuning.

Expression patterns of keratin family members during tooth development and the role of keratin 17 in cytodifferentiation of stratum intermedium and stellate reticulum.

Keratins are typical intermediate filament proteins of the epithelium that exhibit highly specific expression patterns related to the epithelial type and stage of cellular differentiation. They are important for cytoplasmic stability and epithelial integrity and are involved in various intracellular signaling pathways. Several keratins are associated with enamel formation. However, information on their expression patterns during tooth development remains lacking. In this study, we analyzed the spatiotemporal expression of keratin family members during tooth development using single-cell RNA-sequencing (scRNA-seq) and microarray analysis. scRNA-seq datasets from postnatal Day 1 mouse molars revealed that several keratins are highly expressed in the dental epithelium, indicating the involvement of keratin family members in cellular functions. Among various keratins, keratin 5 (Krt5), keratin 14 (Krt14), and keratin 17 (Krt17) are highly expressed in the tooth germ; KRT17 is specifically expressed in the stratum intermedium (SI) and stellate reticulum (SR). Depletion of Krt17 did not affect cell proliferation in the dental epithelial cell line SF2 but suppressed their differentiation ability. These results suggest that Krt17 is essential for SI cell differentiation. Furthermore, scRNA-seq results indicated that Krt5, Krt14, and Krt17 exhibited distinct expression patterns in ameloblast, SI, and SR cells. Our findings contribute to the elucidation of novel mechanisms underlying tooth development.

Filament formation mechanisms in yield-stress fluid-enabled embedded ink writing

Embedded ink writing (EIW), an emerging material extrusion-based three-dimensional (3D) printing strategy, has demonstrated great potential for diverse applications. EIW consists of three key components: support bath, ink, and printing conditions. Filament formation in EIW is significantly affected by the coupling effects of these components, which is still unclear. This work aims to fundamentally unveil the filament formation processes and mechanisms within support bath materials with various rheological properties. A broader range of path speed is utilized to ensure the formation of diverse representative filaments from low- and high-viscosity hydrogel inks. By varying the combination of support bath, ink, and printing conditions, ten types of filaments are observed during EIW and their formation mechanisms are explained in detail. Particularly, when designing a support bath for EIW, thixotropic time serves as the baseline to determine the functionality of the bath. A relatively long thixotropic time can facilitate the formation of well-defined filaments. In addition, the support bath’s yield stress decides the allowed maximum path speed. High yield stress is necessary if path speed is targeted in a higher range. Based on the experimental findings, a position-shape-size evaluation system is established and proposed for comprehensively evaluating printed filaments, which is helpful in filtering suitable filaments for EIW. Finally, complex 3D structures including a human nose and a human ear are printed at a high speed within the support bath with suitable rheological properties to bridge the gap between filament formation mechanisms and practical 3D printing applications.

Pengaruh Penambahan Pigmen Warna pada Filamen PLA SUNLU Colors dan SUNLU Natural

3DP technology is experiencing rapid development and is widely used in various fields. PLA material is widely used as a material for making filaments used in 3D printing (3DP). PLA filament in 3DP is widely used because it has many advantages, including biocompatible, biodegradable, and non-toxic. When compared with other filament materials, PLA material is easier and safer to use because the temperature used is relatively lower so it is more energy efficient compared to other filament materials. SUNLU is a well-known manufacturer that provides various types of quality filaments, including PLA Colors and PLA Natural, where each type of SUNLU PLA filament has its characteristics and advantages. The choice of PLA filament type is adjusted to the desired printing needs, including the desired color and visual effect. The use of color pigments in PLA filaments with various color choices is used to produce objects that are more attractive and more flexible in their use in various fields. This experimental research was carried out to determine the effect of adding color pigments to SUNLU PLA Colors and SUNLU PLA Natural 1.75 mm filament samples with predetermined sample manufacturing variables. This research uses the ASTM D638 type V standard tensile test so that the tensile strength value of each sample can be determined and the maximum value from the tensile test can be determined. The results of this research will show a comparison of the tensile strength between SUNLU PLA Colors filament samples and SUNLU PLA Natural 1.75 mm. The tensile test results of the SUNLU PLA Natural sample had a higher value, namely 53.98 MPa, and for the SUNLU PLA Colors Orange and Gray samples, each had a tensile strength value of 46.58 MPa and 46.63 MPa. These results show that adding color pigments to the filament affects the strength of the resulting 3D-printed samples

Conceptual Design and Materials Selection of the FDM Composites for Passenger Vehicle’s Spoiler

One of the additive manufacturing techniques available is Fused Deposition Modeling (FDM), which offers advantages in design flexibility, cost-effectiveness, and the ability to produce intricate designs. Therefore, FDM for the 3D-printed vehicle’s car spoiler is a subject that can be explored. The FDM technology can significantly reduce time and cost before mass production, and the vehicle’s car spoiler was used as the case study in this research. The research investigates the mechanical properties of various commercial PLA composite filaments, addressing the lack of specifications provided by manufacturers. Testing four types of filaments—PLA/bamboo, PLA/coconut, PLA/wood, and PLA/metal. This research also emphasizes the conceptual design generation and selection for the passenger vehicle’s spoiler. Five design concepts were generated using the morphological chart for the passenger vehicle’s spoiler. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method was used as the decision-making tool. As a result, PLA/metal, with 53.65 MPa and 70.23 MPa, showed the highest tensile and flexural strength values, respectively. Design concept 5 with the infill pattern of rib + I was the best from the finite element analysis (FEA) using SolidWorks simulation software. Finally, the TOPSIS technique revealed PLA/metal as the best PLA composite filament for car spoilers, scoring first in performance score with a value of 0.5774. This study demonstrates that by using a systematic approach, researchers may choose the best design concept and material choice by combining the conceptual design, experimental, simulation, and TOPSIS methods.

CryoEM reveals the structure of an archaeal pilus involved in twitching motility

Amongst the major types of archaeal filaments, several have been shown to closely resemble bacterial homologues of the Type IV pili (T4P). Within Sulfolobales, member species encode for three types of T4P, namely the archaellum, the UV-inducible pilus system (Ups) and the archaeal adhesive pilus (Aap). Whereas the archaellum functions primarily in swimming motility, and the Ups in UV-induced cell aggregation and DNA-exchange, the Aap plays an important role in adhesion and twitching motility. Here, we present a cryoEM structure of the Aap of the archaeal model organism Sulfolobus acidocaldarius. We identify the component subunit as AapB and find that while its structure follows the canonical T4P blueprint, it adopts three distinct conformations within the pilus. The tri-conformer Aap structure that we describe challenges our current understanding of pilus structure and sheds new light on the principles of twitching motility.

Unlocking the nanoparticle emission potential: a study of varied filaments in 3D printing.

This study investigates nanoparticle emission during 3D printing processes, assessing various filament materials' impact on air quality. Commonly used 3D printers, including both filament and resin-based types, were examined. The study's scope encompasses diverse filament materials like ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), PETG (polyethylene terephthalate glycol), ASA (acrylonitrile styrene acrylate), TPU (thermoplastic polyurethane), PP (polypropylene), nylon, and wood-based variants, alongside three types of resins. The research delves into the relationship between the type of material and nanoparticle emissions, emphasizing temperature's pivotal role. Measurement instruments were employed for nanoparticle quantification, including an engine exhaust particle sizer spectrometer, condensation particle counter, and nanozen dust counters. Notably, results reveal substantial variations in nanoparticle emissions among different filament materials, with ASA, TPU, PP, and ABS showing considerably elevated emission levels and characteristic particle size distribution patterns. The findings prompt practical recommendations for reducing nanoparticle exposure, emphasizing printer confinement, material selection, and adequate ventilation. This study offers insights into potential health risks associated with 3D printing emissions and provides a basis for adopting preventive measures.

Investigation of wettability and wear properties on 3D printed Polylactic acid/Molybdenum disulfide-Silicon carbide polymeric composite for sustainable biomedical applications

In the present work, investigations of the wettability, wear, and morphological study on 3D-printed polylactic acid (PLA)/molybdenum disulfide (MoS2)-silicon carbide (SiC) based composite have been performed. In the first stage, the PLA/MoS2-SiC composite was fabricated from the different types of filaments of 1.75 ± 0.10 mm size by taking MoS2-SiC as reinforcement at various extrusion temperatures (150°C–160°C) and screw rotational speed (3–7 r/min) of the extruder setup. The Taguchi L9 orthogonal array was used to design the experiments for 3D printing by varying the filament type, range of nozzle temperature (200°C–210°C), and infill density (40%–90%). The pin-on-disk (POD) setup was used for measuring specific wear rate (SWR) and showed the lowest value of 0.00141 g/N-m when composites were 3D printed by taking filaments manufactured at the parametric combination of 160°C extruder temperature and 7 r/min rotational speed, while 3D printed at 210°C nozzle temperature and 40% infill density. Contact angle (CA) values indicated that the reinforcement of MoS2 and SiC in PLA resulted in hydrophilic surface formation due to morphology and increased roughness (including mean roughness (Sa), mean root square of the Z data (Sq), and the highest peak (Sz)). The significantly increased surface free energy (SFE) of MoS2-SiC-reinforced PLA composite compared to pure PLA was reported which makes the prepared composite a promising candidate to be used for biocompatible implants with high wear resistance.