Search Results (2,126)

Polylactic acid (PLA) is considered as an attractive polymer due to its renewable origin, biodegradability, and promising tensile strength and modulus. However, its inherent brittleness, characterized by a low impact resistance and elongation at break, can significantly restrict its application. This work proposes a new insight to improve the toughness of PLA while keeping its biocompatibility by incorporating two biocompatible ionic liquids (ILs), 1-ethyl-3-methylimidazolium ethyl sulfate ([emim][EtSO₄]), and tris(2-hydroxyethyl) methylammonium methylsulfate ([Tris][MeSO₄]). The modified PLA systems were thoroughly characterized to evaluate their mechanical and thermal behavior. Results demonstrated that the addition of 1 wt% of either IL resulted in significant improvement in modulus. Increasing the amount of IL resulted in an increase in the toughness while maintaining the material’s original stiffness and also the thermal stability. Furthermore, the foaming potential of the modified PLA using supercritical CO₂ was investigated as an environmentally friendly processing method. The ionic liquids contributed positively to the foamability of the material, suggesting improved gas solubility and cell nucleation during the foaming process. The addition of both IL decreased the cell size and resulted in narrower cell size distribution. These findings highlight the potential of ionic liquid-modified PLA systems for the processing of lightweight, and high-performance packaging materials. Full article

One of the current and serious environmental problems is the pollution due to microplastics. There is an urgent need for biodegradable and bio-based materials for numerous applications, including food packaging. In this work we examine the bio-based polyester cutin for its potential to be used as food packaging material, in terms of migration, based on the Hansen Solubility Parameters (HSP). Cutin is a cross-linked polymer that is swelled by various solvents. We use the degree of swelling of cutin in carefully selected solvents of various polarities in order to estimate the HSP of cutin. Some solvents can induce alteration of the chemical structure of cutin, as proven by Fourier Transform Infrared (FTIR) measurements. This interferes with the process of estimation of the HSP and is discussed in depth. The distance R_a and the Relative Energy Difference (RED) between the HSP of cutin and various food components are calculated and used to predict the existence of favorable interactions between cutin and the food components, which is translated to a high probability for the existence of migration and permeation. Experimental confirmation of one prediction based on HSP is provided by UV-VIS photometry. Similar calculations were performed for other polyesters (poly(lactic acid) and poly(hydroxy butyrate)). Cutin exhibits compatibility with substances of low polarity, such as fats and lipids and non-polar compounds found in essential oils. Thus, migration into fatty foods is expected as well as sorption and permeation of some (volatile) compounds into cutin. Nevertheless, we conclude that the overall migration risk for cutin is lower than the one of other bio-based polyesters. HSP can be used for initial screening of potential migration risks; however, further research is necessary in order to assess the occurrence, extent, and significance of the actual migration. Full article

A comprehensive investigation was conducted focusing on two series of poly(lactic acid) (PLA)-based nanocomposites filled with small amounts (0.5 and 1.0%) of metal (Ag/Cu) nanoparticles (NPs). Our work aimed to synthesize PLA/Ag nanocomposites via in situ ring-opening polymerization (ROP), and for comparison purposes, the same materials were also prepared via solution casting followed by melt mixing. PLA/Cu nanocomposites were also prepared via melt extrusion. Gel permeation chromatography (GPC) and intrinsic viscosity measurements [η] showed that the incorporation of Ag nanoparticles (AgNPs) resulted in a decrease in the molecular weight of the PLA matrix, indicating a direct effect of the AgNPs on its macromolecular structure. Fourier-transform infrared spectroscopy (FTIR) revealed no significant changes in the characteristic peaks of the nanocomposites, except for an in situ sample containing 1.0 wt% of AgNPs, where slight interactions in the C=O region were detected. Differential scanning calorimetry (DSC) analysis confirmed the semi-crystalline nature of the materials. Glass transition temperature was strongly affected by the presence of NPs in the case of the in situ-based samples. Melt crystallized studies suggested potential indirect polymer–NP interactions, while isothermal melt crystallization experiments confirmed the nucleation ability of the NPs. The mechanical performance was assessed via tensile and flexural measurements, revealing that the in situ-based samples exhibited remarkable flexibility. Moreover, during the three-point bending tests, none of the in situ nanocomposite samples broke. In this context, next-generation PLA-based nanocomposites have been proposed for advanced applications, including flexible printed electronics. Full article

The poly-lactic acid (PLA) coating was widely applied to the WE43 alloy to modulate its degradation for biomedical implants, a strategy whose long-term efficacy is critically dictated by the coating’s protective and ion-permeation properties under dynamic physiological flow. This work systematically investigates the corrosion performance under the such flow condition using a novel in situ monitoring method. This method enables a direct, in situ assessment of both the ion-permeation rate across the PLA membrane acted as the coating and the concurrent evolution of the electrochemical properties of the membrane as well as the WE43 alloy substrate. Results revealed that the applied flow accelerated the formation of micro-cracks in the PLA membrane, which facilitated the permeation of Na⁺ and Cl⁻ ions and thereby intensified the corrosion of the underlying substrate. During the initial 15 days, the ion permeation rates for Na⁺ and Cl⁻ ions under the flow condition were 0.097 and 0.042 mmol/(L·h), respectively. The degradation rate of the substrate exhibited a strong positive correlation with the concentration of permeated Cl⁻ ions. In contrast, the deposition of calcium-containing compounds was identified as a time-dependent process, governed by the permeation kinetics of Ca²⁺ ions through the membrane. Full article

Treating bacterial infections has become increasingly difficult due to the rise in antibiotic-resistant bacterial strains. Strategies involving the targeted delivery of antibiotics have been proposed to minimize the administered antibiotic doses. This study aims to develop the first double-modified nanovehicle capable of increasing bacterial membranes’ permeability while specifically targeting Staphylococcus aureus, one of the foremost pathogens responsible for global mortality rates. Thus, polymeric NPs composed of poly(lactic-co-glycolic acid) (PLGA) were produced, and their surface was modified with TAT peptide to increase the membranes’ permeability and folic acid (FA) to direct the NPs to S. aureus. The nanosystem showed spherical morphology with sizes of 174 ± 4 nm, a monodisperse population (polydispersity index of 0.08 ± 0.02), and a zeta potential of −2.5 ± 0.1 mV. The NPs remained stable for up to four months during storage. Fluorescence-based flow cytometry analysis proved that the double modification of PLGA NPs increased the interaction of the NPs with S. aureus, with fluorescence increasing from 71 ± 3% to 87 ± 1%. The nanosystem slightly affected the growth curve of S. aureus by extending both the lag time (from 2.5 ± 0.2 to 2.88 ± 0.4 h) and the exponential phase, as evidenced by an increase in the half-maximum growth time (from 3.9 ± 0.2 to 4.4 ± 0.1 h). Furthermore, the nanocarrier showed no toxicity for human dermal fibroblast cells, maintaining a 100% cell viability at the highest concentration tested (100 µM). Therefore, the proposed FA/TAT-functionalized nanocarrier presented promising features to be successfully used as a delivery vehicle of antimicrobials to fight S. aureus. Full article

This work investigates the effect of a bio-based plasticizer derived from used sunflower oil on the crystallization behavior of poly (lactic acid) (PLA), comparing it with that of the conventional plasticizer tributyrin. This study aims to explore biodegradable alternatives to petroleum-based materials and to evaluate their potential in modulating PLA crystallization kinetics without altering the crystalline structure of the resulting sustainable material solutions with tailored performance. PLA-based films containing 5%, 10%, and 15% plasticizer were prepared and characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-Ray diffraction (XRD). DSC analysis showed a decrease in the glass transition temperatures upon plasticization, with tributyrin producing a more pronounced effect than the recycled sunflower oil plasticizer. XRD patterns confirmed that the crystalline form of PLA remained unchanged regardless of plasticizer type or content. POM revealed that both plasticizers influenced crystallization kinetics, with the bio-plasticizer promoting larger and more sparsely distributed spherulites than tributyrin, indicating differences in nucleation efficiency and crystal growth. Crystallization kinetics were further analyzed using the Avrami model, the Lauritzen-Hoffman theory, and the isoconversional method. Avrami analysis indicated that nucleation mechanisms were largely unaffected, although the overall crystallization rate increased upon plasticization. Lauritzen-Hoffman analysis confirmed crystallization in Regime III, controlled by nucleation, while isoconversional analysis showed reduced activation energy in plasticized PLA. These findings highlight the ability of bio-derived plasticizers to modulate PLA crystallization, promoting the valorization of a food industry residue as a sustainable plasticizer. This study hopes to contribute relevant knowledge to emerging areas of polymer processing, such as 3D printing, to develop sustainable and high-performance PLA-based materials. Full article

Background/Objectives: Palmitoylethanolamide (PEA) is an endogenous lipid mediator with endocannabinoid-like activity. Despite its therapeutic potential in muscle-related inflammatory disorders, including sarcopenia, its clinical use is limited by poor solubility and bioavailability. To overcome these issues, we developed hybrid nanoparticles combining poly(lactic-co-glycolic acid) (PLGA) and lipids to enhance PEA encapsulation and ok delivery. Methods: PEA-loaded hybrid nanoparticles (PEA-Hyb-np) were produced via a modified single-emulsion solvent evaporation method using stearic acid and Gelucire^® 50/13 as lipid components. Characterization included particle size, morphology, PDI, and zeta potential, as well as DSC, FT-IR, and XRD analyses. For the biological evaluation in a C2C12 myoblasts cell culture, coumarin-6-labeled nanoparticles were employed. Results: PEA-Hyb-np showed mean particle sizes of ~150 nm, with internal lipid–polymer phase separation. This structure enabled high encapsulation efficiency (79%) and drug loading (44.2 mg/g). Drug release in physiological and non-physiological media was enhanced due to drug amorphization, confirmed by DSC, FT-IR, and XRD analyses. Cytocompatibility studies showed no toxicity and improved cell viability compared to unloaded nanoparticles. Cellular uptake studies by confocal microscopy and flow cytometry demonstrated efficient and time-dependent internalization. Conclusions: PEA-Hyb-np represent a promising delivery platform to improve the solubility, bioavailability, and therapeutic efficacy of PEA for muscle-targeted applications. Full article

Guided bone regeneration membranes are essential for bone formation. While non-resorbable membranes require removal surgery, resorbable membranes such as poly (lactic-co-glycolic acid) PLGA are widely used; however, issues with animal-derived components and degradation control have been identified. A novel bilayer membrane composed of synthetic poly (L-lactic acid-co-ε-caprolactone) (PBM) was developed, offering prolonged degradability and elasticity. This study compared the wound-healing effects of PBM and PLGA membranes in vivo and in vitro experiments. In vivo, maxillary molars were extracted from rats, and membranes were placed over the sockets. Healing was evaluated histologically at 1, 2, 3, 4 and 8 weeks. In vitro, oral epithelial cells and fibroblasts were seeded on both sides of PBM. Adhesion and permeability of the membranes were assessed. In vivo, both groups displayed similar mucosal healing. However, PBM preserved a clear bone-soft tissue boundary. In vitro, the surface of PBM supported significantly greater oral epithelial cell adhesion than the reverse side, with no differences for fibroblasts. Both sides of PBM exhibited better protein permeability compared to PLGA. PBM maintained distinct bone-soft tissue separation in rat extraction sockets, suggesting its potential as an effective space maintainer in guided bone regeneration. Further studies are warranted to investigate the mechanisms underlying these favorable properties. Full article

A biopolymer blend of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephtalate) (PBAT) in a 60/40 weight ratio was investigated as a potential green alternative to thermoplastic polyurethane (TPU) for material extrusion (MEX)-based additive manufacturing. A comparison of the two materials was conducted based on their tensile mechanical properties, evaluated using 3D-printed specimens fabricated with three distinct infill raster orientations (0°, ±45°, and 90°). The results showed that the tensile strengths of the two materials were relatively similar, ranging from 14.7 to 34.8 MPa, depending on the raster angle. However, the stiffness of PLA/PBAT was considerably higher than that of TPU, as reflected by Young’s modulus values an order of magnitude greater. While the elongation at break was comparable at 0° infill orientation (214% for PLA/PBAT and 265% for TPU), TPU exhibited better tolerance to increasing raster angles, with elongation only decreasing to 134% at 90°. In contrast, PLA/PBAT dropped drastically to 2%. Full article

Background: In response to the emergence of immune-evasive variants of SARS-CoV-2, this study explores a novel heterologous vaccination strategy using a microparticulate formulation approach that is delivered via oral dissolving film (ODF) formulations into the buccal cavity. Heterologous administration has the potential to generate cross-reactive antibodies, which can be especially beneficial against viruses with ever-mutating variants. Moreover, the microparticulate oral dissolving film-based vaccine approach is a non-invasive vaccine delivery platform. Methods: The vaccine design incorporated whole inactivated Delta and Omicron variants of the virus, administered at prime and booster doses, respectively, effectively encapsulated in a Poly(lactic-co-glycolic) acid (PLGA) polymer matrix, and adjuvanted with Alum to enhance immune activation. Following vaccination, serum, mucosal, and tissue samples were analyzed to evaluate humoral and cellular immune responses against the model antigen, as well as other variants such as Alpha and Beta variants, to understand the cross-reactive response. Result: In vitro evaluations confirmed the vaccine’s safety and its ability to stimulate immune responses. On administering microparticulate oral dissolving films to mice, whole inactivated delta and omicron variant-specific antibodies were observed in serum samples along with neutralizing titers in terminal week. The formulated vaccine showed significant secretory IgA antibody levels in mucosal samples. Moreover, CD4⁺ and CD8a cellular responses were observed in tissue samples of spleen and lymph nodes, along with antibodies (IgG, IgA, and IgM) detected in lung supernatant samples. Humoral and cellular cross-reactive antibodies were observed in the samples. Conclusions: This approach offers a promising platform for developing next-generation vaccines capable of inducing broad immunity. Full article

L-arginine, a basic amino acid, exhibits high biocompatibility, reactivity, and absorbability. It was selected as the co-polymer modification monomer for L-lactic acid with the objective of enhancing the hydrophilicity of poly(lactic acid) (PLA), neutralizing the acidity of PLA degradation products, and regulating the degradation cycle. The copolymer poly(lactic acid-co-arginine) (PLAA) was synthesized by direct melting polycondensation of L-arginine and L-lactic acid, and the structures and properties of PLAA were characterized. The results indicated the presence of –NH₂, –NH–, and NH= in the molecular chain of the copolymer PLAA. Furthermore, the PLAA was identified as an amorphous copolymer. The “PLAA/CHCl₃/C₆H₁₄” ternary phase diagram was constituted by nonsolvent-induced phase separation (NIPS) by selecting chloroform (CHCl₃) as a good solvent and n-hexane (C₆H₁₄) as a nonsolvent. The phase diagram displays three distinguishable regions: the homogeneous zone, the metastable zone, and the phase separation zone. These regions are identified by the binodal and spinodal curves. The ternary phase diagram establishes a theoretical foundation for the preparation and processing of PLAA nanoparticles, composite materials, and porous fibers or membranes. Full article

Fibres play a crucial role in diverse biomedical applications, ranging from tissue engineering to drug delivery. Electrospinning has emerged as a simple and versatile technique for producing ultrafine fibres at micro- to nanoscale dimensions. Synthetic biopolymers are effective cues to replace damaged tissue in the biomedical field, both in vitro and in vivo applications. Among them, poly (L-lactic acid) (PLLA) is a renewable, environmentally friendly biopolymer material. Polycaprolactone (PCL) is a synthetic polymer with good biocompatibility and biodegradation characteristics. However, both electrospun PLLA and PCL fibres have their limitations. To overcome these shortcomings, electrospinning PLLA/PCL blend fibres has been the subject of many studies. This review discusses the different parameters for the electrospinning of PLLA/PCL-based fibres for biomedical applications. Furthermore, we also discuss how electrospun PLLA/PCL-based scaffolds can be modified or combined with other biomaterials, such as natural polymers and bioceramics, and examine their in vitro and in vivo applications in various tissue repair strategies. Full article

Biodegradable polymers such as Polycaprolactone (PCL), Polylactic acid (PLA), and Poly(lactic-co-glycolic acid) (PLGA) are attracting attention as key platforms for anticancer drug delivery systems due to their excellent biocompatibility and controllable degradation rates. These polymers can overcome limitations of existing chemotherapeutics, such as low bioavailability, systemic toxicity, and nonspecific cell damage, and contribute to the development of precision medicine approaches and long-acting therapeutics. This paper discusses the chemical and physicochemical properties of these three polymers, their synthetic strategies, and the controlled drug release technology through surface functionalization and stimuli-responsive design. Furthermore, we highlight their potential for use in various formulations, including micelles, nanoparticles, hydrogels, and microspheres, enabling enhanced drug solubility, sustained release, and tumor targeting. Preclinical and clinical applications demonstrate that these polymer-based DDSs represent a promising approach for implementing next-generation precision anticancer treatment strategies, with further potential for clinical translation and widespread adoption. Full article

Poly(lactic-co-glycolic acid) (PLGA) sustained-release systems for intra-articular (IA) delivery aim to extend joint residence time and reduce the reinjection frequency of conventional IA therapies. This review synthesizes current understanding of PLGA degradation, the acidic microenvironment inside degrading microspheres, and release behavior in joints, and surveys clinical experience with extended-release corticosteroid depots alongside emerging platforms for nonsteroidal and biologic agents. To situate PLGA within the broader IA field, we briefly summarize selected non-PLGA sustained-release approaches—such as multivesicular liposomes, hyaluronic acid conjugates, and hybrid matrices—to contextualize comparative performance and safety. For proteins and peptides, central barriers include acidification inside degrading microspheres, aggregation during fabrication and storage, and incomplete or delayed release, as illustrated by glucagon-like peptide-1 analog formulations. Mitigation strategies span pH buffering, excipient-based stabilization, and gentler manufacturing that improve encapsulation efficiency and preserve bioactivity. Translation hinges on manufacturing scale-up and quality systems that maintain critical particle attributes and enable informative in vitro–in vivo interpretation. Clinically, prolonged symptom relief after single dosing has been demonstrated for corticosteroid depots (e.g., ~50% pain reduction over 12 weeks with a single PLGA–triamcinolone injection), whereas repeat-dose safety and indication expansion beyond the knee remain active needs best addressed through multicenter trials incorporating imaging and patient-reported outcomes. Consistent real-world performance will depend on controlling batch-to-batch variability and implementing pharmacovigilance approaches suited to long dosing intervals, enabling broader clinical adoption. Full article

Cellulose stands out as a promising alternative to conventional polymers in food packaging due to its abundance, renewability, biodegradability and structural robustness. Despite these advantages, its natural low resistance to water and fats limits its direct application, necessitating the use of protective coatings to enhance its functionality. In this context, the use of biopolymeric coatings such as poly(lactic acid) (PLA), starch, lignin, chitin and chitosan has emerged as a sustainable solution, providing effective barriers against moisture and oils. These coatings not only improve the functional performance of cellulosic substrates but also reduce reliance on fossil-based plastics, fostering compostable systems and supporting a circular economy. This review analyzes recent developments in biopolymer-coated cellulosic packaging materials, focusing on their resistance to water and fats. The aim is to assess their potential for sustainable food packaging applications. The findings highlight how these innovations contribute to global sustainability goals, such as reducing plastic waste, lowering carbon emissions, and decreasing dependence on non-renewable resources. Full article