Search Results (679)

Three-dimensional cell culture systems are relevant in vitro models for studying cellular behavior. In this regard, this present study investigates the interaction between human osteoblast-like cells and 3D-printed scaffolds mimicking physiological and osteoporotic bone structures under simulated microgravity conditions. The objective is to assess the effects of scaffold architecture and dynamic culture conditions on cell adhesion, proliferation, and metabolic activity, with implications for osteoporosis research. Polylactic acid scaffolds with physiological (P) and osteoporotic-like (O) trabecular architectures were 3D-printed by means of fused deposition modeling technology. Morphometric characterization was performed using micro-computed tomography. Human osteoblast-like SAOS-2 and U2OS cells were cultured on the scaffolds under static and dynamic simulated microgravity conditions using a rotary cell culture system (RCCS). Scaffold biocompatibility, cell viability, adhesion, and metabolic activity were evaluated through Bromodeoxyuridine incorporation assays, a water-soluble tetrazolium salt assay, and an enzyme-linked immunosorbent assay of tumor necrosis factor-α secretion. Both scaffold models supported osteoblast-like cell adhesion and growth, with an approximately threefold increase in colonization observed on the high-porosity O scaffolds under dynamic conditions. The dynamic environment facilitated increased surface interaction, amplifying the effects of scaffold architecture on cell behavior. Overall, sustained cell growth and metabolic activity, together with the absence of detectable inflammatory responses, confirmed the biocompatibility of the system. Scaffold microstructure and dynamic culture conditions significantly influence osteoblast-like cell behavior. The combination of 3D-printed scaffolds and a RCCS bioreactor provides a promising platform for studying bone remodeling in osteoporosis and microgravity-induced bone loss. These findings may contribute to the development of advanced in vitro models for biomedical research and potential countermeasures for bone degeneration. Full article

This research presents a comprehensive methodology for calibrating Discrete Element Method (DEM) parameters governing rice grain interactions with biodegradable Polylactic Acid (PLA) components in agricultural bucket elevator systems. Rice grains, a critical global food staple requiring efficient post-harvest handling, were modeled as three-sphere clusters to accurately represent their physical dimensions (6.5 mm length), while the Hertz–Mindlin contact model provided the theoretical framework for particle interactions. The calibration process employed a multi-phase experimental design integrating Plackett–Burmann screening, steepest ascent method, and Face Central Composite Design to systematically identify and optimize critical micro-mechanical parameters for agricultural material handling. Statistical analysis revealed the coefficient of static friction between rice and PLA as the dominant factor, contributing 96.49% to system performance—significantly higher than previously recognized in conventional agricultural processing designs. Response Surface Methodology generated predictive models achieving over 90% correlation with experimental results from 3D-printed PLA shear box tests. Validation through comparative velocity profile analysis during bucket elevator discharge operations confirmed excellent agreement between simulated and experimental behavior despite a 20% discharge velocity variance that warrants further investigation into agricultural material-specific phenomena. The established parameter set enables accurate virtual prototyping of sustainable agricultural handling equipment, offering post-harvest processing engineers a powerful tool for optimizing bulk material handling systems with reduced environmental impact. This integrated approach bridges fundamental agricultural material properties with sustainable engineering design principles, providing a scalable framework applicable across multiple agricultural processing operations using biodegradable components. Full article

In recent years, there has been a growing interest in the frictional anisotropy of snake scale-inspired surfaces, especially its potential applications in enhancing the bearing capacity of foundations (piles, anchor elements, and suction caissons) and reducing materials consumption and installation energy. This study first investigated the frictional properties and surface morphologies of the ventral scales of Cantor’s rat snakes (Ptyas dhumnades). Based on the findings on the snake scales, a novel snakeskin-inspired geosynthetic reinforcement (SIGR) is developed using 3D-printed polylactic acid (PLA). A series of pullout tests under different normal loads (25 kPa, 50 kPa, and 75 kPa) were performed to analyze the pullout behavior of SIGR in sandy soil. Soil deformation and shear band thickness were measured using Particle Image Velocimetry (PIV). The results revealed that the ventral scales of Ptyas dhumnades have distinct thorn-like micro-protrusions pointing towards the tail, which exhibit frictional anisotropy. A SIGR with a unilateral (one-sided) layout scales (each scale 1 mm in height and 12 mm in length) could increase the peak pullout force relative to a smooth-surface reinforcement by 29% to 67%. Moreover, the peak pullout force in the cranial direction (soil moving against the scales) was found to be 13% to 20% greater than that in the caudal direction (soil moving along the scales). The pullout resistance, cohesion, and friction angle of SIGR all showed significant anisotropy. The soil deformation around the SIGR during pullout was more pronounced than that observed with smooth-surface reinforcement, which suggests that SIGR can mobilize a larger volume of soil to resist external loads. This study demonstrates that SIGR is able to enhance the pullout resistance of reinforcements, thereby improving the stability of reinforced soil structures, reducing materials and energy consumption, and is important for the sustainability of geotechnical engineering. Full article

Objectives: This research focuses on the development of fabrication approaches for microparticles intended for controlled drug delivery. The primary objective is to identify the most suitable polymer type, particle size, and morphology for encapsulating a water-soluble crystalline drug. Optimizing these parameters may enhance structural stability and prolong the release of this active substance. Methods: The microparticles were fabricated through the encapsulation of a drug substance within a polymer carrier and employing polymer casting on prepatterned surfaces, followed by the loading of drug precipitates and the application of a sealing layer. The crystalline powder 1-allyl-2,5-dimethylpiperidol-4 hydrochloride served as the core cargo material, while the walls of these particles were composed of polylactic acid (PLA) and a poly (α-caprolactone) (PCL) in a 70:30 composition ratio. Results: The size and volume of the microparticles were found to be dependent on the geometric parameters of the template and the concentration of the polymer solutions. The study demonstrates the formation, physical dimensions, and particle count at varied polymer compositions and concentrations. The formation of the PLA and PCL mixture occurred solely through physical interactions. Scanning electron microscopy (SEM) and optical microscopy were employed to observe the appearance and physical dimensions of the microparticles. The obtained data confirm that tailored polymer compositions can yield consistent particle morphology and a suitable drug elution rate. Conclusions: The results indicate that microparticles sealed with an optimal polymer composition exhibit enhanced release properties. This finding highlights the feasibility of microencapsulation at precise ratios and concentrations of polymers to achieve the long-lasting effects of water-soluble drugs. Full article

This study investigates the combined use of electron beam irradiation (EBI) and nanotechnology to develop improved food packaging films. EBI, commonly applied for sterilization, can alter polymer microstructure, while irradiated cellulose nanocrystals (CNCs) offer enhanced functionality when incorporated into biopolymer matrices. Here, CNCs were irradiated with doses up to 50 kGy, leading to the formation of carboxyl and aldehyde groups, confirmed by FTIR analysis, as a consequence of the initial formation of free radicals and peroxides that may subsist in that original form or be converted into various carbonyl groups. Flexible films were obtained by incorporating pristine and EB-irradiated CNCs in an internal mixer, using minute amounts of poly(ethylene oxide) (PEO) to facilitate the dispersion of the filler within the polymer matrix. The resulting PLA/PEO/CNC films were evaluated for their mechanical, thermal, barrier, and antioxidant properties. The results showed that structural modifications of CNCs led to significant enhancements in the performance of the composite films, including a 30% improvement in water barrier properties and a 50% increase in antioxidant activity. These findings underscore the potential of irradiated CNCs as effective additives in biopolymer-based active packaging, offering a sustainable approach to reduce dependence on synthetic preservatives and potentially extend the shelf life of food products. Full article

Polylactic acid (PLA) fabrics exhibit significant sunlight reflectivity and high emissivity within the atmospheric window, making them suitable as the foundational material for this study. This research involves the modification of one side of the fabric with hydrophilic agents and titanium dioxide (TiO₂), while the opposite side is treated with MXene and subsequently coated with polydimethylsiloxane (PDMS) to inhibit oxidation of the MXene. Through these surface modifications, a thermal management fabric based on PLA was successfully developed, capable of passively regulating temperature in response to environmental conditions and user requirements. The study discusses the optimal concentrations of TiO₂ and MXene for the fabric, and characterizes and evaluates the functional surface of the PLA. Surface morphology analyses and tests indicate that the resulting functional PLA fabrics possess excellent ultraviolet (UV) resistance, favorable air permeability, high sunlight reflectivity on the TiO₂-treated side, and superior photothermal conversion capabilities on the MXene-treated side. Furthermore, photothermal effect tests conducted under a light intensity of 1000 W/m² reveal that the MXene-treated fabric exhibits a heating effect of approximately 25 °C, while the TiO₂-treated side demonstrates a cooling effect exceeding 5 °C. This study developed PLA functional fabrics with heating and cooling capabilities. Full article

Fused Filament Fabrication (FFF) is a widely adopted additive manufacturing technique, yet its mechanical performance is highly dependent on process parameters, particularly nozzle diameter and printing speed. This study evaluates the influence of these parameters on the tensile behavior of Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA), aiming to determine optimal conditions for enhanced strength. ASTM D638-Type IV specimens were printed using nozzle diameters ranging from 0.05 to 0.25 mm and speeds from 15 to 80 mm/s. For ABS, tensile strength increased from 56.46 MPa to 60.74 MPa, representing a 7.6% enhancement, as nozzle diameter increased, with the best performance observed at 0.25 mm and 45 mm/s, attributed to improved melt flow and interlayer fusion. PLA exhibited a non-linear response, reaching a maximum strength of 89.59 MPa under the same conditions, marking a 22.3% enhancement over the minimum value. The superior performance of PLA was linked to optimal thermal management that enhanced crystallinity and interlayer bonding. Fractographic analysis revealed reduced porosity and smoother fracture surfaces under optimized conditions. Overall, PLA consistently outperformed ABS across all settings, with an average tensile strength advantage of 47.5%. The results underscore the need for material-specific parameter tuning in FFF and offer practical insights for optimizing mechanical performance in applications demanding high structural integrity, including biomedical, aerospace, and functional prototyping. Full article

This study developed sustainable biocomposites composed of polylactic acid (PLA) and surface-treated pineapple core powder (PACP), fabricated via extrusion and fused deposition modelling (FDM). PACP loadings of 1–3 vol% were combined after chemical modification with NaOH and silane to improve interfacial bonding. Particle morphology showed increased porosity and surface roughness following treatment. The melt flow index (MFI) increased from 31.56 to 35.59 g/10 min at 2 vol% PACP, showing improved flowability. Differential scanning calorimetry (DSC) showed the emergence of cold crystallization (T_cc ~121 °C) and an increase in crystallinity from 35.7% (neat PLA) to 47.3% (2 vol% PACP). Thermogravimetric analysis showed only slight decreases in T₅ and T_max, showing the thermal stability. The mechanical testing of extruded filaments showed increased modulus (1463 to 1518 MPa) but a decrease in tensile strength and elongation. For the 3D-printed samples, elongation at break increased slightly at 1–2 vol% PACP, likely because of the improvement in interlayer fusion. Though, at 3 vol% PACP, the mechanical properties declined, consistent with filler agglomeration observed in SEM. Overall, 2 vol% PACP offered the optimal balance between printability, crystallinity, and mechanical performance. These results reveal the possibility of PACP as a value-added biowaste filler for eco-friendly PLA composites suitable for extrusion and 3D printing applications. Full article

The surface modification of zinc oxide nanoparticles (ZnONPs) with organic compounds has been shown to improve their dispersibility. In this study, to develop a highly functional material, ZnONP modified with 6-amino-1-hexanol bearing both amino and hydroxyl functional groups was synthesized. Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analyses confirmed that functionalized ZnONP was successfully obtained by a hydrothermal synthetic method. The mechanical properties of composite films of polylactic acid (PLA) reinforced with the functionalized ZnONP were then evaluated. The composite containing functionalized ZnONP exhibited a higher maximum stress than that containing unmodified ZnONP. These ZnONP/polymer composites therefore show promise as novel high-performance materials. Full article

Bio-nanocomposites represent an advanced class of materials that combine the unique properties of nanomaterials with biopolymers, enhancing mechanical, electrical and thermal properties while ensuring biodegradability, biocompatibility and sustainability. These materials are gaining increasing attention, particularly in biomedical applications, due to their ability to interact with biological systems in ways that conventional materials cannot. Graphene and graphene oxide (GO), two of the most well-known nanocarbon-based materials, have garnered substantial interest in bio-nanocomposite research because of their extraordinary properties such as high surface area, excellent electrical conductivity, mechanical strength and biocompatibility. The integration of graphene-based nanomaterials within biopolymers, such as polysaccharides and proteins, forms a new class of bio-nanocomposites that can be tailored for a wide range of biological applications. This review explores the synthesis methods, properties and biotechnological applications of graphene-based bio-nanocomposites, with a particular focus on polysaccharide-based and protein-based composites. Emphasis is placed on the biotechnological potential of these materials, including drug delivery, tissue engineering, wound healing, antimicrobial activities and industrial food applications. Additionally, biodegradable polymers such as polylactic acid, hyaluronic acid and polyethylene glycol, which play a crucial role in biotechnological applications, will be discussed. Full article

In this work, biocomposites of polylactic acid (PLA) and polypropylene (PP) with micronized cellulose (MC) were produced by mold injection and subjected to accelerated aging with ultraviolet (UV) radiation. The tests took place over 10 weeks, during which the produced specimens were exposed to a total of 1050 h of ultraviolet light. During the UV aging test, images were captured, and spectral reflectance and colorimetric measurements were carried out on the specimens exposed to UV and on specimens of the same materials kept in the dark (originals). As expected, only residual color differences were observed in the original specimens with values of ΔE*_ab always below 0.5. On the other hand, spectral reflectance and colorimetric changes were noticed over time in the specimens subjected to UV radiation. In particular, the values of ΔE*_ab increased over time and were found to be higher for PLA with MC compared to PP with MC. Values of ΔE*_ab = 4.7, 9.0, and 10.4 were obtained for weeks 1, 5, and 10, respectively, for the specimens of PLA with MC, whereas ΔE*_ab = 4.5, 6.8, and 7.3 were obtained for weeks 1, 5, and 10, respectively, for the specimens of PP with MC. Therefore, it was found that the specimens of PLA with MC showed greater color fading compared to the specimens of PP with MC when subjected to UV exposure. In addition, it was also found in this work that besides the color differences noted in the tested specimens, those made of PP with MC also showed signs of surface damage. Full article

In the face of accelerating urbanization and the growing demand for environmentally responsible materials and designs, this study presents the development and implementation of a modular parklet demonstrator fabricated using dual-material 3D printing. The structure integrates polylactic acid (PLA) and wood-filled PLA (wood/PLA), combining the mechanical robustness of pure PLA in the core with the tactile and aesthetic appeal of wood-based biocomposite on the surface. The newly developed dual-nozzle 3D printing approach enabled precise spatial control over material distribution, optimizing both structural integrity and sustainability. A comprehensive evaluation was conducted for developed filaments and printed materials, including optical microscopy, coupled thermogravimetry analysis and Fourier Transform Infrared Spectroscopy (TG/FTIR), differential scanning calorimetry (DSC), and chemical and mechanical resistance testing. Results revealed distinct thermal behaviors and degradation pathways between filaments and printed parts composed of PLA and PLA/wood. The biocomposite exhibited slightly increased sensitivity to aggressive chemical environments and mechanical wear, dual-material prints maintained high thermal stability and interlayer adhesion. The 3D-printed demonstrator bench and stools were successfully deployed in public spaces as a functional urban intervention. This work demonstrates the feasibility and advantages of using biocomposite materials and dual-head 3D printing for the rapid, local, and sustainable fabrication of small-scale urban infrastructure. Full article

The development of effective drug delivery systems, in terms of their application route and release profile, is crucial for improving the therapeutic outcomes of all bioactive compounds. In this study, we explored the encapsulation of 5-fluorouracil, a commonly used chemotherapeutic agent, in poly(lactic acid) films for the first time and the role of chitosan particles in the structure, as no previous studies have examined their potential for this purpose. The objective is to enhance the sustained release of 5-FU and minimise the burst release step while leveraging the biocompatibility and biodegradability of these polymers. PLA films were fabricated using a solvent casting method, and 5-FU was encapsulated either directly within the PLA matrix or loaded into chitosan particles, which were then incorporated into the film. The physicochemical properties of the films, including morphology, wettability, phase state of the drug, thermal stability, drug loading efficiency, and release kinetics, were evaluated along with their barrier and mechanical properties. The results indicate a change in morphology after the addition of the drug and/or particles compared to the empty film. Additionally, the strain value at break decreased from nearly 400% to below 15%. Young’s modulus also changes from 292 MPa to above 500 MPa. The addition of chitosan particles lowered the permeability and vapour transmission rate slightly, while dissolving 5-FU increased them to 241 g/m²·24 h and 1.56 × 10⁻¹³ g·mm/m²·24 h·kPa, respectively. Contact angle and surface energy values went from 71° and 34 mJ/m² for pure PLA to below 53° and around 58 mJ/m² for the composite structures, respectively. Drug release tests, conducted for 8 h, indicated a nearly 2-fold decrease in the amount of drug released from the film with particles within this period, from around 45% for bare particles and PLA film to 25% for the combined structure, indicating the potential of this system for sustained release of 5-FU. Full article

This study focused on composites of magnetite magnetic nanoparticles (MNP) and poly(lactic acid) (PLA) prepared via sonochemical synthesis. The evaluation of MNP loadings (2, 5, 10, 15, and 20 wt.%) provided insights into the structural and reactivity properties of the materials. Methods used included XRD, FT-IR and Raman spectroscopy, SEM and TEM microscopy, textural and thermal analysis (TG and DTA), and magnetic property measurements. The agreement between theoretical and experimental MNP loadings was good. XRD patterns showed predominantly MNP and semicrystalline phases, with a minor maghemite phase detected by FT-Raman and magnetic measurements. FT-IR analysis revealed interactions between MNP and PLA, confirmed by thermal analysis showing higher transition temperatures for the composites (145 °C) compared to pure PLA (139 °C). FT-Raman spectra also indicated that PLA helps prevent iron oxide oxidation, enhancing nanoparticle stability. SEM and TEM micrographs showed well-dispersed, spherical nanoparticles with minimal agglomeration, dependent on MNP loading. The nanocomposites exhibited low N₂ adsorption, resulting in low surface area (~2.1 m²/g) and porosity (~0.03 cm³/g). Magnetic analysis indicated that in the 2MNP/PLA sample, MNP were in a superparamagnetic-like regime at 300 K, suggesting good dispersion of 2 wt.% MNP in the PLA matrix. Full article

Poly(lactic acid) (PLA) holds significant promise as an option in the field of packaging materials due to its biodegradability and antibacterial properties. Therefore, it is vital for developing packaging materials while improving their heat resistance, and transparency is essential for guaranteeing its application. Using a self-assembled nucleating agent with hydrogen bonding and thermodynamically compatible transparent polymethyl methacrylate (PMMA), this study fabricated PLA micro-crystals with an interface blurred grain. Furthermore, the crystalline structure-property relationship was investigated in different isothermal crystallization conditions; it was possible to achieve higher crystallinity while maintaining the transparency of PLA/10 wt% PMMA/0.3 wt% nucleating agent blends. Compared to other temperatures, the crystallization rate of PLA blends under annealing conditions at 90 °C was higher when induced by three different nucleating agents. Particularly, in the presence of the TC-328 nucleating agent, the system exhibited a crystallinity of 32%, the smallest grain size, and an increased Tg of 61.3 °C, as well as an elevated heat deformation temperature (HDT) from 54.13 °C to 63.2 °C. The smaller nucleating agents with high surface energy enhanced the interaction between the PLA and PMMA, enhancing the PLA/PMMA tensile strength and HDT. These findings may pave the way for designing novel blends for packaging or heat-resistant devices. Full article