Search Results (2,179)

Poly(lactic acid) (PLA)-based nanocomposites containing a mixture of graphene nanoplatelets (GNP) and carbon nanotube (CNT) as hybrid fillers were prepared using a solution-assisted sonication process followed by melt processing. The effects of the filler dispersion on dielectric properties and microwave absorbing (MWA) performance were systematically investigated. Two ionic liquids (ILs), trihexyl-(tetra-decyl)phosphonium bis (trifluoromethanesulfonyl)imide (IL1) and 11-carboxyundecyl-triphenylphosphonium bromide (IL2), were employed as dispersing agents for the carbonaceous fillers. Incorporation of IL-treated fillers resulted in enhanced dielectric permittivity and improved MWA performance of the PLA composites. The MWA properties were evaluated in X- band and Ku-band. A minimum reflection loss (RL) of −34 dB and an effective absorption bandwidth (EAB) of 2.1 GHz were achieved for the composite containing GNP/CNT/IL2 (HB3) at a weight ratio of 2.5:0.5:0.5 wt% with one 3 mm thick layer. The superior performance of IL2 is attributed to π-π and π-cation interactions between its phenyl-containing cation and the carbonaceous fillers, as well as improved compatibility with the PLA matrix due to carboxyl groups. Additionally, three-layered composite structures, combining PLA/GNP as the outer layer with IL-assisted hybrid fillers in the core and PLA/CNT at the bottom layer, achieved an extended EAB of 4.5 GHz for GNP/HB2/CNT arrangement and 4.35 GHz for the GNP/HB3/CNT arrangement, driven by enhanced scattering and internal reflection of microwaves. These results demonstrate the potential of IL-assisted hybrid filler dispersion in PLA for developing biodegradable materials with multifunctional applications as charge storage capacitors and microwave absorbing materials for sustainable electronics. Full article

Three-dimensional biomaterial scaffolds with controlled geometry and surface nanoarchitecture are essential for advancing polymer processing strategies in tissue engineering. Conventional electrospinning generates nanofibrous structures but has limited ability to reproduce defined three-dimensional shapes or achieve high pattern fidelity. This study aimed to develop a scalable processing method for producing biodegradable scaffolds with precisely controlled microstructure and geometry using phase separation–assisted electrospray. Poly (lactic acid) microcapsules with tunable diameters and porous nanofibrous surfaces were fabricated under controlled humidity and deposited onto conductive molds to obtain two- and three-dimensional scaffold shapes. The manufacturing process required only simple electrospray equipment and static molds, without mechanically complex collectors or moving stages. The resulting scaffolds replicated mold features with resolutions down to 200 μm and achieved thickness up to 600 μm. The nanofibrous microcapsule surfaces supported strong adhesion and metabolic activity of HepG2 cells, while cellular penetration into deeper scaffold regions remained limited to approximately 80 μm. These findings indicate that electrospray-mediated microcapsule deposition is a practical polymer-processing approach that integrates nanofibrous surface formation with mold-defined shaping, offering a reproducible and scalable method for fabricating structurally precise and biologically compatible three-dimensional scaffolds. Full article

Glycerol-(9,10-trioxolane) trioleate (OTOA) is a promising material that combines good plasticizing properties for PLA with profound antimicrobial activity, which makes it suitable for application in state-of-the-art biomedical and packaging materials with added functionality. In this study, the biodegradation kinetics of PLA + OTOA mixed films under soil conditions was assessed over 180 days. Structural and morphological changes that occurred on the surface and in the volume of the films during degradation were scrutinized using DSC, X-ray diffraction, IR, and UV spectroscopy. Morphological changes were assessed using optical and confocal microscopes. The different behavior of the PLA + OTOA blend films during decomposition in soil is explained by their structure and the rate of release of antibacterial OTOA from the PLA matrix. The decomposition rate constants were determined for all films, where k_d for PLA samples is 28 µm·year⁻¹, for samples containing 10% and 30% OTOA k_d is 2 µm·year⁻¹, and for PLA + 50% OTOA samples k_d = 34 µm·year⁻¹. This is explained by changes in the structure and degree of crystallinity of materials during the process of aging in the soil. These results clarify the biodegradation processes of biomaterials containing antibacterial agents in their structure. Full article

This study evaluated the thermal properties, crystallinity, particle size, morphology, and in vivo local inflammation and persistence of two poly-L-lactic acid (PLLA) injectable implants, Sculptra^® (PLLA-SCA) and GANA V^® (PLLA-GA). PLLA-SCA and PLLA-GA underwent differential scanning calorimetry and X-ray powder diffraction to evaluate their thermal properties and degree of crystallinity. X-ray powder diffraction spectra displayed a sharper, more intense peak for PLLA-GA than PLLA-SCA, with smaller peaks on either side of the main peak of PLLA-GA but not PLLA-SCA. Differential scanning calorimetry thermograms indicated three thermal events for both PLLA-SCA and PLLA-GA. For PLLA-SCA, the first two events occurred between 65 °C and 90 °C, and the third event occurred at 165 °C. For PLLA-GA all three events occurred between 156 °C and 169 °C. Heating samples to 120 °C and cooling to room temperature prior to differential scanning calorimetry resulted in no thermal events being observed between 65–90 °C with either product, while three events were observed with PLLA-GA and one event with PLLA-SCA between 156 °C and 169 °C. The median volume distribution diameter was 46.4 µm for PLLA-SCA and 31.7 µm for PLLA-GA. Scanning electron microscopy showed PLLA-GA particles were irregular in shape, had no sharp edges and had a wrinkled and crimped surface, while PLLA-SCA particles displayed plate-like shapes and had smoother surfaces. In vivo inflammatory reactivity scores indicated a slight reaction for PLLA-SCA at all time points (3.7 ± 1.1, 6.1 ± 1.6, 5.7 ± 1.2 and 6.2 ± 1.2 at 2, 12, 26 and 52 weeks, respectively), while for PLLA-GA, a moderate reaction was observed at 12 and 26 weeks (2.9 ± 1.5, 10.1 ± 1.0, 9.4 ± 0.7 and 7.1 ± 1.3 at 2, 12, 26 and 52 weeks, respectively). PLLA-SCA and PLLA-GA had similar persistence scores at 2, 12 and 26 weeks, while at 52 weeks the score was markedly higher for PLLA-SCA versus PLLA-GA (1.9 ± 0.2 versus 0.7 ± 0.2). In conclusion, PLLA-SCA is more amorphous than PLLA-GA. The single melting point of PLLA-SCA contrasts with the broader spectrum of melting points for PLLA-GA suggests a more homogenous formulation of PLLA-SCA. This, and its less crystalline structure, result in the slower degradation rate and more sustained biological response of PLLA-SCA compared with PLLA-GA. The physiochemical properties of PLLAs affect the biological response in clinical practice and should be taken into consideration when selecting a PLLA treatment for aesthetic use. Full article

Background: While intravenous administration of nanoparticles (NPs) is effective for targeting the lungs and liver, directing them to other organs and tissues remains challenging. Methods: Here, we report alternative administration routes that improve organ-specific accumulation of poly (lactic-co-glycolic acid) (PLGA) NPs (100 nm, negatively charged) loaded with the near-infrared dye Cyanine 7 (Cy7). NP cytotoxicity was evaluated in HEK293, mMSCs, C2C12, L929, and RAW264.7 cells. Hemocompatibility was assessed using WBCs and RBCs. NPs were administered via the tail vein, carotid, renal, and femoral arteries in BALB/c mice. Administration safety was evaluated by laser speckle contrast imaging and histological analysis. NP biodistribution and accumulation were assessed using in vivo and ex vivo fluorescence tomography and confocal microscopy of cryosections. Results: PLGA-Cy7 NPs demonstrate low cytotoxicity even at high doses and exhibit good hemocompatibility. Administration of NPs through the mouse carotid, renal, and femoral arteries significantly increases accumulation in the target ipsilateral brain hemisphere (31.7-fold) and salivary glands (28.3-fold), kidney (13.7-fold), and hind paw (3.6-fold), respectively, compared to intravenous administration. Injection of NPs through arteries supplying the target organs and tissues does not result in significant changes in blood flow, morphological alterations, or irreversible embolization of vessels, provided the procedure is performed correctly and the optimal dosage is used. Conclusions: These results highlight the potential of intra-arterial delivery of NPs for organ-specific drug targeting, underscoring the synergistic impact of advances in materials science, minimally invasive endovascular surgery, and nanomedicine. Full article

Background: Guided Bone Regeneration (GBR) relies on barrier membranes, for which polylactic acid (PLA) and its copolymer poly(lactic-co-glycolic acid) (PLGA) are promising biodegradable polymers. However, their inherent hydrophobicity limits biological performance, and the evidence regarding how specific modifications affect key human cell types, particularly osteoblasts and fibroblasts, remains scattered. Methods: A systematic review was conducted to synthesize the in vitro evidence on the response of primary human osteoblasts and fibroblasts to polylactic acid-based materials. Following a pre-registered protocol (10.17605/OSF.IO/CE8KB), a comprehensive search was performed across four major databases, and the risk of bias in the included studies was assessed using an adapted OHAT tool. Results: Twenty-six studies were included, which showed that polylactic acid-based materials have limited bioactivity, and their modification significantly improves cellular responses. The incorporation of bioceramics and growth factors, or alterations in surface topography, notably enhanced osteogenic differentiation and mineralization in osteoblasts. For gingival fibroblasts, topographical modifications like micro-grooves guided cell alignment and modulated proliferation. Conclusions: Native polylactic acid-based materials display limited bioactivity. However, functionalization through bioceramics incorporation, growth factor delivery, and surface topographical modification is crucial for transforming them into bioactive scaffolds capable of achieving the dual biofunctionality required for successful GBR. Full article

Driven by environmental concerns, the packaging industry is shifting toward high-performance and bio-based coating alternatives. In this research, poly(methylmethacrylate) (PMMA) and modified cellulose nanocrystal (m-CNC) were employed as reinforcing agents to develop sustainable poly (lactic acid)-based coatings for packaging applications. Various formulations, influenced by polymer matrix blends and m-CNC loadings (1–5%), were prepared using solvent and applied as protective coating on cardboard paper substrates. The grammage of polymeric coatings (CG) on paper was also investigated using various wet film thicknesses (i.e., 150–250 μm). Accordingly, key parameters including water contact angle, thermal behavior, mechanical performances and barrier properties were systematically evaluated to assess the effectiveness of the developed nanocomposite coatings. As a result, nonylphenol ethoxylate surfactant-modified cellulose nanocrystals exhibited good dispersion and stable suspension in chloroform for one hour, improving compatibility and interaction of polymer–CNC fillers. The water vapor permeability (WVP) of PLA-coated papers was significantly reduced by blending PMMA and increasing the content of m-CNC nanofillers. Furthermore, CNC incorporation enhanced the oil resistance of PLA/PMMA-coated cardboard. Pronounced improvements in barrier properties were observed for paper substrates coated with dry coat weight or CG of ~20 g/m² (corresponding to 250 μm wet film thickness). Coatings based on blended polymer—particularly those reinforced with nanofillers—markedly enhanced the hydrophobicity of the cardboard papers. SEM-microscopy confirmed the structural integrity and morphology of the nanocomposite coatings. Regarding mechanical properties, the upgraded nanocomposite copolymer (PLA-75%/PMMA-25%/m-CNC3%) exhibited the highest bending test and tensile strength, achieved on coated papers and free-standing polymeric films, respectively. Based on DSC analysis, the thermal characteristics of the PLA matrix were influenced to some extent by the presence of PMMA and m-CNC. Overall, PLA/PMMA blends with an optimal amount of CNC nanofillers offer promising sustainable coatings for the packaging applications. Full article

Background/Objectives: Empagliflozin (EMPA) was repurposed for Alzheimer’s disease (AD) treatment via buccal delivery, exploiting novel nanofibers (NFs) integrating chitosan (Cs), silk fibroin (Fb), and poly(lactic acid) (PLA). Methods: EMPA-loaded Cs/Fb/PLA NFs were electrospun in different formulations to optimize the formulation parameters. The optimized formulation was then investigated for its enhanced in vivo effect. Results: Optimized nanofiber diameters ranged from 459 ± 173 to 668 ± 148 nm, possessing bead-free morphology confirmed by SEM and satisfactory mechanical properties. EMPA was successfully well-dispersed in the polymer matrix as evidenced by FTIR, XRD, and drug content. The optimized NFs displayed a hydrophilic surface (contact angle < 90°), and biphasic drug release with sustained EMPA liberation (84.98% over 24 h). In vivo, buccal EMPA-Cs/Fb/PLA NFs in an AlCl₃-induced AD rat model significantly reduced brain-amyloid-β, phosphorylated tau, IL-1β, and AGER expression by 2.88-, 2.64-, 2.87-, and 2.50-fold, respectively, compared to positive controls, and improved locomotor activity (1.86-fold) and cognitive performance (T-maze) (4.17-fold). Compared to pure EMPA, the nanofiber formulation achieved further reductions in amyloid-β (1.78-fold), p-tau (1.42-fold), IL-1β (1.89-fold), and AGER (1.38-fold), with efficacy comparable to memantine. Histopathological examination revealed preservation of the hippocampal neuronal structure. Conclusions: The findings suggest EMPA-loaded Cs/Fb/PLA NFs as a promising non-invasive, sustained-release buccal delivery platform for AD therapy, offering multimodal neuroprotection through modulation of the Aβ–AGER–p-tau axis. Full article

This study evaluates the flexural strength of poly lactic acid parts (PLAs) fabricated with fused filament fabrication (FFF) by systematically analyzing the combined effects of infill density, infill pattern, and built-up orientation. Therefore, samples with 10, 30, 50, 70, and 90% infill densities were printed with cubic and triangular patterns in all three possible built-up directions (Cartesian X, Y, Z) and subjected to a standardized three-point bending test according to ISO 178, while printing time was concurrently assessed to quantify trade-offs between mechanical performance and manufacturing efficiency. The results show that a cubic infill with layers transverse to the bending load (Y-direction) offers the highest flexural strength of about 31 MPa for 90% infill density at comparably low printing times. In addition to significantly longer printing times, samples printed in the X-direction achieved the highest flexural strengths across all configurations tested for both infill patterns examined, up to densities of approximately 60%. Full article

Biocompatible poly(lactic acid) (PLA) was plasticized with poly(ethylene glycol) (PEG) added at concentrations of 10, 15, and 20 wt.% relative to PLA, and then processed into gyroid triply periodic minimal surface (TPMS) scaffolds using fused filament fabrication (FFF) 3D printing. The influence of PEG concentration and gyroid structure (50% infill density) on thermal transitions, crystallinity, and low–temperature shape-memory performance was systematically investigated. The shape-memory effect (SME) of the PLA–based scaffolds was tailored through compositional control and structural design. Shape recovery under thermal activation at 40 °C and 50 °C was examined to reveal the correlation between composition and structure in governing low–temperature shape-memory behavior. The optimal composition (PLA/10 PEG, 50% gyroid infill) achieved shape recovery with a recovery ratio (R_r) of 97 ± 1% at 40 °C within 6 ± 1 min, demonstrating optimal shape-memory activation close to physiological temperature. Structural and morphological changes were characterized using ATR–FTIR, Raman spectroscopy, DSC, XRD, and SEM, providing comprehensive insight into the plasticization of the PLA matrix and its impact on structure–property relationships relevant to bone tissue engineering. Full article

This work focused on the development of eco-friendly bio-composites based on polylactic acid (PLA) and sugarcane bagasse (SCB) as a natural fiber from Moroccan vegetable waste. First, the fiber surface was treated with an alkaline solution to remove non-cellulosic components. Then, the composite materials with various amounts of treated sugarcane bagasse (TSCB) were fabricated using two routes, melt processing and solvent casting. The primary objective was to achieve high fiber dispersion/distribution and homogeneous bio-composites. The dispersion properties were analyzed using scanning electron microscopy (SEM). Subsequently, the thermal, mechanical, and melt shear rheological properties of the obtained PLA-based bio-composites were investigated. Through a comparative approach between the dispersion state of fillers with extrusion/injection molding and solvent casting method, the work aimed to identify the most suitable processing route for producing PLA-based composites with optimal dispersion, improved thermal stability, and mechanical reinforcement. The results support the potential of TSCB fibers as an effective bio-based additive for PLA filament production, paving the way for the development of eco-friendly and high-performance materials designed for 3D printing applications. Since the solvent-based route did not allow further improvement and presents clear limitations for large-scale or industrial implementation, the transition toward 3D printing became a natural progression in this work. Material extrusion offers several decisive advantages, notably the ability to preserve the original morphology of the fibers due to the moderate thermo-mechanical stresses involved, and the possibility of manufacturing complex geometries that cannot be obtained through conventional injection molding. Although some printing defects may occur during layer deposition, the mechanical properties obtained through 3D printing remain promising and demonstrate the relevance of this approach. Full article

Poly(lactic acid) (PLA) has emerged as a leading bio-based polymer due to its renewability, processability, and biodegradability, yet its broader adoption remains constrained by limitations in thermal stability, mechanical performance, and end-of-life control. This review provides a comparative and application-oriented overview of recent advances in PLA from synthesis and catalyst landscapes to structure–property–biodegradation relationships and practical applications. Representative polymerization routes and catalyst systems are critically compared in terms of achievable molecular weight, stereochemical control, scalability, and sustainability. Key structure–property modification strategies—including stereocomplex formation, blending, and copolymerization—are quantitatively evaluated with respect to thermal and mechanical properties, highlighting inherent trade-offs. Importantly, environment-specific biodegradation behaviors are assessed using representative quantitative metrics under industrial composting, soil, marine, and enzymatic conditions, underscoring the strong dependence of degradation on both material design and testing environment. Finally, application-driven requirements for food packaging, fibers, and agricultural materials are discussed alongside regulatory considerations, processing constraints, and qualitative cost positioning relative to conventional polymers. By integrating recent representative studies into comparative tables and synthesis-driven discussions, this review offers design guidelines for tailoring PLA-based materials toward targeted performance and sustainable deployment. Full article

This review systematically outlines recent advances in long-acting microneedle-based transdermal drug delivery systems. It begins by introducing the fundamental principles of microneedles (MNs) as a minimally invasive technology and categorizes them by delivery mechanism into solid, coated, dissolving, hollow, hydrogel-forming, and biodegradable types. The review then discusses the design strategies and material platforms engineered for sustained drug release. A key focus is on biodegradable synthetic polymers, such as polylactic acid (PLA), poly (lactic-co-glycolic acid) (PLGA), and polycaprolactone (PCL), and natural polymers like silk fibroin (SF) and chitosan (CS), which enable prolonged drug release through their tunable degradation rates. Furthermore, it describes the incorporation of advanced drug carriers, including liposomes and polymeric nanoparticles/microparticles, into MNs to further extend release duration and enhance drug-loading capacity. Finally, the major challenges for clinical translation are addressed, including ensuring batch-to-batch consistency in manufacturing, maintaining sterility, and the necessity for more comprehensive validation of long-term in vivo efficacy and safety. Full article

Electrospinning of poly(lactic acid) (PLA) commonly relies on toxic organic solvents, which limit its sustainability and biomedical applicability. In this work, a green electrospinning process was developed using dimethyl carbonate (DMC), a biodegradable and low-toxicity solvent, combined with acetone as a volatile co-solvent to promote efficient jet solidification. Three commercial PLA grades were evaluated for solubility and spinnability, and PLA 4043D was identified as the most suitable for DMC and acetone systems. The electrospinning parameters, including solvent ratio, flow rate, and applied voltage, were systematically optimized to achieve stable jet formation and uniform fiber morphology. Under optimized conditions, the process produced continuous, bead-free nanofibers with a mean diameter of ~1 µm and uniform nanoscale surface porosity resulting from differential solvent evaporation. The resulting fibers were characterized in terms of morphology, structure, thermal behavior, and mechanical performance, confirming increased amorphous content, high porosity (about 78%), and tensile strength of ~3 MPa for the selected electrospinning condition. This study demonstrates that DMC-based solvent systems enable a sustainable and potentially biocompatible route, considering the lower toxicity of the solvents employed, offering a green alternative to conventional toxic processes for the fabrication of medical scaffolds. Full article

The growing accumulation of plastic and electronic waste highlights the urgent need for sustainable and biodegradable polymers. However, developing intrinsically conductive biodegradable polymers remains challenging, particularly for packaging and sensing applications. Poly(lactic acid) (PLA) is intrinsically non-conductive, and enhancing its functionality without compromising structural integrity is a key research goal. In this study, PLA-based filaments were developed using melt extrusion, incorporating cellulose nanocrystals (CNCs), graphene nanoplatelets (GNPs), and carbon nanotubes (CNTs), individually and in hybrid combinations with total filler contents between 1 and 5 wt%. The inclusion of CNC enhanced the dispersion of GNP and CNT, promoting the formation of interconnected conductive networks within the PLA matrix, allowing the percolation threshold to be reached at a lower fillers concentration. Hybrid formulations showed a balance melt strength and processability suitable for fused deposition modelling (FDM) 3D printing and prototypes successfully made. This study also provides the first systematic evaluation of temperature-dependent thermal conductivity of PLA-based composites at multiple temperatures (25, 5, and −20 °C), relevant to typical food and medical supply chains conditions. Full article