Search Results (589)

Amphotericin B (AmB) is a broad-spectrum antifungal agent and a long-standing standard of care; however, its clinical use is compromised by poor solubility, off-target tissue distribution and severe dose-limiting toxicity. AmB-loaded poly (D, L-lactide-co-glycolide) nanoparticles (PLGA-AmB-NPs) were developed and characterized with respect to their physicochemical properties, antifungal activity against A. fumigatus biofilms, in vivo efficacy in the Galleria mellonella infection model, and hemolytic toxicity in vitro. Blank PLGA nanoparticles (PLGA-NPs) and PLGA-AmB-NPs exhibited mean diameters of 165 nm (PDI 0.075) and 120 nm (PDI 0.210), respectively, with negative zeta potential values consistent with colloidal stability in aqueous media. PLGA-AmB-NPs showed significantly enhanced activity against 24 h A. fumigatus biofilms compared with free AmB at concentrations of 5 and 10 µg/mL, while unloaded PLGA-NPs were inactive. Infected G. mellonella larvae treated with PLGA-AmB-NPs displayed markedly improved survival over a 5-day period relative to those receiving equivalent doses of free AmB. Furthermore, PLGA-AmB-NPs induced substantially lower hemolysis of human red blood cells than free AmB across all tested concentrations (5–20 µg/mL). PLGA-AmB-NPs represent a promising polymeric platform for the treatment of A. fumigatus infections. Full article

Flexible implantable electrodes require biocompatibility, mechanical stability, and sufficient electrical conductivity for effective neural interfacing. This work examines ultrasonic treatment during poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) impregnation of electrospun poly(D,L)-lactide (PLA) nonwoven scaffolds as a route to improve filler distribution and functional performance. Four sample types were studied: pristine PLA (untreated and sonicated) and PLA–PEDOT:PSS composites prepared with and without ultrasonication. Scanning electron microscopy shows that ultrasonic treatment suppresses the formation of continuous surface films and promotes homogeneous three-dimensional penetration of PEDOT:PSS throughout the fibrous network. As a result, electrical resistivity decreases by a factor of 7.3, from 294.4 to 40.2 Ω·m. Contact-angle measurements reveal markedly enhanced wettability, with sonicated composites exhibiting rapid water uptake (5–13 s), unlike non-sonicated controls. These findings demonstrate that ultrasound-assisted PEDOT:PSS impregnation yields conductive, highly wettable, and structurally stable scaffolds, highlighting their potential for flexible implantable neural electrodes. Full article

Poly(l-lactic acid) or poly(l-lactide) (PLLA) is an optically active polymer derived from renewable sources and fully biodegradable. It is known that PLLA assumes a left-handed helix in the solid state and also in solution it still keeps a certain degree of helical structure. Here, we examine the Optical Rotatory Dispersion (ORD) behavior of two grades of PLLA (medium molecular weight and hexadecyl-terminated or high molecular weight for 3D printing) in 13 different solvents and analyze the experimental ORD data through the Moffitt–Yang equation. Furthermore, the ORD data of PLLA in additional 6 solvents were taken from the literature and analyzed with the Moffitt-Yang approach. The results suggest that, also in solution, PLLA maintains the left-handed helix, and the most structurizing and helicogenic solvents for PLLA are ethyl acetate, acetonitrile, and certain chlorinated solvents. The equilibrium association constant (K) and other thermodynamic parameters (ΔG°, ΔH° and ΔS°) between PLLA and polyphenylacetylene (PPA, another helical polymer in the solid state and in solution) were determined in trichloromethane, dichloromethane, and tetrahydrofuran. The K values found suggest a strong helix-helix interaction between the two polymers. The ORD analysis of the PLLA-PPA solutions shows evidence of the extrinsic Cotton effect and confirms the chiral helicity induction between the two polymers with 1:1 complex formation. Full article

The formation of stereocomplex (SC) crystallites in poly(L-lactide) (PLLA)/poly(D-lactide) (PDLA) blends has attracted significant attention due to its potential to enhance the performance of biodegradable polymer films. In this study, the effect of solvent evaporation kinetics on the crystallization behavior, microstructure, and functional properties of PLLA/PDLA blend films was systematically investigated. Films with various blend ratios were prepared under open-lid (fast evaporation) and closed-lid (slow evaporation) conditions. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS) analyses revealed that slow solvent evaporation significantly promotes stereocomplex formation, particularly at the equimolar (50:50) composition, resulting in a higher degree of crystallinity and a more compact structure compared to fast evaporation conditions. These structural changes were directly correlated with improved functional properties. The optimized PLLA/PDLA (50:50) films exhibited a substantial reduction in water vapor permeability from 22.7 to 3.11 g·mm/m²·day·kPa (~86% decrease) and a marked decrease in microbial growth, as evidenced by reduced total plate count (TPC) values compared to neat polymers. The enhanced barrier performance and reduced microbial proliferation were attributed to the reduced free volume and increased tortuosity associated with densely packed stereocomplex crystallites, as supported by DSC and WAXD results. These findings demonstrate the importance of solvent evaporation kinetics in tailoring structure–property relationships to control stereocomplex formation and multiscale structural organization, providing a practical strategy for biodegradable packaging films. Full article

Alginate hydrogels offer mild ionic gelation and tunable porosity for drug delivery, yet their hydrophilic, macroporous networks suffer from rapid initial burst release of water-soluble payloads. Here we introduce a hierarchical barrier-engineering strategy in which poly(D,L-lactide-co-glycolide)/poly(ethylene glycol) (PLGA/PEG) blend coatings are applied via dip-coating to Ca²⁺-cross-linked alginate beads (~1 mm) and microgels (~100 µm). For beads, three-cycle PLGA/PEG multilayer coating suppressed the initial swelling rate (dQ/dt) by ~50% and reduced 1 h burst release from >85% to ~60%, functioning as an “early-burst buffer” rather than a long-term depot. For microgels, a single PLGA/PEG layer partially attenuated burst release; however, an additional PLGA outer shell (double-barrier architecture) shifted the release-governing mechanism from swelling-dominated to diffusion-barrier-dominated control, limiting 10 min release to <10%. Core–shell formation was verified by confocal laser scanning microscopy (CLSM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS); thermogravimetric analysis (TGA) showed ~73–79% coating retention after 9 days in phosphate-buffered saline (PBS, 37 °C). A vacuum re-loading process further improved encapsulation efficiency (>50% for beads, >20% for microgels) without compromising gel integrity. In beads, burst control was governed by swelling suppression; in microgels, the additional PLGA shell shifted control to diffusion-barrier-dominated release, demonstrating that barrier architecture must be adapted to particle scale. Full article

In this study, a hierarchical design strategy is introduced for tuning the release of rosmarinic acid (RA) from electrospun poly(L-lactide) (PLA) fibrous materials via surface engineering with chitosan/hyaluronic acid (Ch/HA) polyelectrolyte complexes (PECs). RA was selectively incorporated within the fiber bulk, the PEC coating, or both, enabling control over its spatial distribution. The PEC coating, formed by sequential dip coating, was shown to act as a diffusion-regulating layer with a dual role—either retarding RA release or promoting rapid initial release when functioning as a surface-associated reservoir. As a result, the release kinetics could be systematically tuned depending on the coating architecture and RA localization. Thorough characterization confirmed successful coating formation, enhanced surface hydrophilicity, and improved mechanical performance. All RA-loaded materials retained high antioxidant activity and exhibited pronounced antibacterial and antifungal effects against Staphylococcus aureus, Escherichia coli, and Candida albicans. This work introduces PEC-modified electrospun systems as a versatile platform for the rational design of multifunctional fibrous biomaterials with controlled release profiles, with potential applications in wound healing and drug delivery. Full article

The manuscript details the influence of high-temperature and high-shear processing, as well as radiation sterilization, on properties of bioresorbable and osteoconductive, patient-tailored alloplastic scaffolds for guided bone regeneration. Functionalized poly(l-lactide-co-d,l-lactide) copolymer filled with hydroxyapatite was used to produce two personalized implants for upper and lower jaw reconstruction via 3D printing. Morphology analysis (SEM, µCT), gel permeation chromatography, and thermal analysis quantified the effects of melt processing and sterilization on chain structure. Physical properties of sterilized parts, such as hardness and density, proved suitable for bone implants. Removal of the upper jaw implant after 4 months and of the lower jaw substitute after 18 months enabled monitoring of bioresorption and tissue regrowth over time. Gradual overgrowth of the implants with human tissue, initiated by the osteoconductive filler, was observed, along with time-dependent polylactide degradation, showing up to 92% molar mass reduction. The medical procedures confirmed safety, nontoxicity, non-allergenicity, and, most importantly, the tissue-forming properties of the polylactide-based formulation. Full article

Biodegradable poly(lactide)/poly(ε-caprolactone) (PLA/PCL) systems functionalized with TiO₂-SiO₂ were synthesized via in situ ring-opening polymerization of a eutectic L-lactide/ε-caprolactone system. This work introduces a TiO₂-SiO₂ composite with a dual function, acting as a catalytic initiator that governs polymerization and microstructure, while simultaneously serving as a reinforcing and photocatalytic phase. The system exhibits high polymerization efficiency, reaching conversions up to 99% with low filler loadings (0.1–1.0 wt%). Structural analyses confirm polymer formation and reveal modifications in ester groups associated with coordination-driven mechanisms. Notably, the presence of TiO₂-SiO₂ promotes increased PLA tacticity, directly influencing mechanical performance. The resulting materials show enhanced tensile strength (~250,000 Pa) and Young’s modulus (1.5–2.0 MPa) compared to conventional systems. In addition, excellent photocatalytic activity was achieved, with up to 99.7% degradation of methyl orange. These findings demonstrate a synergistic strategy to simultaneously control polymer structure and functionality, positioning PLA/PCL–TiO₂-SiO₂ systems as promising multifunctional materials for environmental applications. Full article

Background/Objectives: Commercially available drug-eluting stents still suffer from poor blood compatibility, polymer coating delamination, polymer cracking and lack of stability during and after stent implantation that led to adverse events such as stent thrombosis and in-stent restenosis. This article highlights the advantages of using silicon nanofilament (SiNf) as an interface between stent surface and drug-in-polymer coating or bloodstream. Methods: Thin layer of SiNf was successfully formed on the surface of Co-Cr substrate via one-step simple method. For stent applications, sirolimus-in-poly(D,L-lactide) (PDLLA/SRL) matrix was coated on control and SiNf-modified Co-Cr substrates and the stability, cracking, and long-term degradation was compared. Blood compatibility studies were also compared between control and SiNf-modified Co-Cr substrates. Results: The morphology of the filaments showed nanosized structures with nano-gaps between the filaments which support mechanical interlocking of PDLLA/SRL coating and enhanced the coating stability with no coating delamination whereas, the control substrate presented 97% of coating delamination. The PDLLA/SRL coating on stent platform demonstrates smooth and uniform morphology without webbing between stent struts. After stent ballooning, the control stent presented cracking and peeling of the polymer coating from the surface whereas, the SiNf-modified stent did not show any signs of these unfavorable defects. Moreover, SiNf-modified surface showed reduced fibrinogen adsorption and lower number of platelet adhesion with round shape morphology. Conclusions: Overall, this suggests that modifying the metallic substrates with SiNf could act as a universal coating for reinforcing the polymer coating stability, prevent coating defects that accompany stent ballooning, and improve the blood compatibility of the material surfaces that could have various applications to medical implants and devices. Full article

Degradable polymers, such as poly(L-lactide) (PLLA), are widely investigated for biomedical applications, including drug delivery systems and temporary implants. Their functionality can be expanded by incorporating degradable metal microparticles that may influence degradation behaviour and enable additional surface modification strategies. In this study, the feasibility of composites consisting of PLLA and biodegradable iron microparticles was investigated. Composites were fabricated by solvent casting, providing a gentle alternative to thermal processing methods, which often compromise polymer integrity. Composites were evaluated by thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy (SEM), tensile testing, dynamic mechanical analysis, and X-ray photoelectron spectroscopy (XPS). Incorporation of iron altered thermal behaviour and crystallinity of PLLA, indicating interactions between polymer matrix and dispersed metal phase that may affect degradation kinetics and material stability. While iron addition reduced Young’s modulus, tensile strength, and elongation at break, composites maintained sufficient structural integrity for potential biomedical applications. XPS and SEM confirmed the embedding of particles within the polymer matrix, enabling potential post-processing approaches. In vitro direct contact and eluate tests demonstrated good cell viability, whereas exposure to free iron particles resulted in dose- and time-dependent cytotoxic effects. Overall, the results demonstrate the feasibility of solvent-cast PLLA–iron composites for resorbable biomedical applications. Full article

Background/Objectives: Hospital-acquired and fracture-related infections remain major complications in orthopedic trauma surgery, with significant clinical and socio-economic impact. Antibacterial implant surface coatings represent a promising strategy to reduce early postoperative bacterial adhesion and biofilm formation. Methods: This retrospective matched case–control study evaluated the clinical effectiveness of an antibiotic-free fast-resorbable hyaluronic acid and poly-d, l-lactide hydrogel (DAC^®) applied intraoperatively to orthopedic implants. A total of 222 patients with comorbidities who underwent open reduction and internal fixation between May 2023 and April 2024 in two trauma centers were included: 99 patients received the DAC^® coating and 123 served as controls with standard fixation. The primary endpoint was infection incidence within 6 months; secondary endpoints included wound complications, revision surgery, prolonged antibiotic therapy, and bone healing. Results: Postoperative infection incidence was significantly lower in the DAC^® group compared with controls (0.7% vs. 5.3%; p = 0.0363). Wound complications were also reduced (1.3% vs. 8.0%; p = 0.028), and only one patient in the DAC^® cohort required additional surgical interventions or prolonged antibiotic therapy. Bone healing outcomes were comparable between groups, with no delayed unions reported in the treated cohort. Conclusions: Even if larger prospective studies with longer follow-up are required to further confirm these findings and better define long-term safety and effectiveness, the routine intraoperative use of DAC^® hydrogel without antibiotic loading appears to be a safe and promising strategy to reduce early postoperative infections and wound complications in orthopedic trauma patients with comorbidities. Full article

Silica-supported zinc (II)–Schiff-base complexes were prepared through a simple and high-yield immobilization strategy and evaluated as heterogeneous catalysts for the ring-opening polymerization (ROP) of lactide. Silica gel and silica nanoparticles were employed as supports to assess the influence of support morphology and textural properties on catalytic performance. Comprehensive characterization by AAS, BET, SEM, and SEM–EDS confirmed effective anchoring of the Zn complexes, homogeneous metal distribution, and support-dependent textural modifications. The supported catalysts were active in the bulk ROP of racemic and enantiopure lactide, affording PLA with high conversions and moderate dispersities. Silica-gel-supported systems exhibited high and reproducible activity over a wide range of conditions, whereas catalysts supported on silica nanoparticles showed a stronger dependence on reaction time and ligand electronic effects, highlighting the key role of the support in modulating active site accessibility and chain growth. Microstructural and thermal analyses confirmed the formation of atactic PLA from rac-lactide and stereoregular PLLA from L-lactide. Overall, this study demonstrates that silica-supported zinc(II)–Schiff-base complexes constitute an effective and versatile heterogeneous platform for lactide ROP and underscore the importance of support properties in the rational design of sustainable catalysts for biodegradable polyester synthesis. Full article

The use of seven biomaterials was examined in the study: polyethylene (PE), polypropylene (PP), polyurethane (PU), teflon (PTFE), polycaprolactone (PCL), polylactide (PLLA), and a copolymer of poly L-lactide and dibutyryl chitin (PLLA/DBC). The use of these materials has not been discussed in the context of animal reproduction so far. Due to the specific nature of the reproductive system and the high sensitivity of reproductive cells, at the outset the biocompatibility and cytotoxicity of the materials were tested in somatic cell and embryo cultures. Additionally, the material properties of the catheters were determined in terms of the roughness of the internal and external surfaces, the stability of the shape of the catheters, their elasticity, durability, and ductility. Finally, clinical testing of the developed catheters was performed in laparoscopic transplantation of embryos into the uterine tubes of the sows. Significant toxicity of PTFE, PCL and PLLA/DBC towards the embryos was indicated in the cytotoxicity testing. In the materials testing, numerous flaws of the PP, PLLA, and PLLA/DBC catheters were indicated. In the final stage, catheters were developed using PE and PU. In clinical testing, these latter catheters exhibited high effectiveness in transferring embryos. Among the seven biomaterials tested, only polyethylene and polyurethane exhibited high biocompatibility and the material properties mentioned above. There is thus good indication for the introduction of these catheters for embryo transfer in animal reproduction biotechnology. Full article

There has been much development of composites of calcium phosphate and polymers for use as artificial bone, with other applications still ongoing, and clarification of the in vivo absorption mechanism is considered an important perspective. In order to clarify the absorption mechanism of bioabsorbable materials used for artificial bones and bone grafts, we prepared composites of calcium phosphate and polymers and conducted in vivo experiments in experimental animals using composites as implantation samples. Two typical types of calcium phosphate, β-tricalcium phosphate (β-TCP) and unsintered hydroxyapatite (uHA), were used as calcium phosphate, and copolymers of poly-dl-lactide-co-glycolide (PDLGA) and poly-l-lactide-co-glycolide (PLGA) were used as polymers. For samples composed of PDLGA and calcium phosphates, the weight ratios of calcium phosphate were set at 40% and 10% for uHA and 40% for β-TCP (uHA(40), uHA(10) and β-TCP(40), respectively). A composite sample of PLGA and uHA was also prepared with a weight ratio of 10% uHA (uHA(10)/PLGA), intending slow degradation of the polymer matrix compared to PDLGA. The samples were implanted in the metaphysis and diaphysis region of rabbits’ femur for up to 48 weeks. In this study, positron emission tomography/X-ray computed tomography (PET/CT) was used to continuously evaluate the changes in the samples and the accumulation of cells in the animals, and histological evaluation was performed, focusing on the time of characteristic changes in the PET/CT to confirm the cell types. The results are summarized as follows: (1) the absorption mechanism of the materials used in this study was suggested to be mainly phagocytosis by macrophages; (2) the disappearance rate was faster for β-TCP(40) compared with uHA(40); and (3) uHA(10), having a lower proportion of uHA, is not prone to aggregation and exhibited a similar disappearance result to β-TCP(40). These results suggest that phagocytosis by macrophages is the dominant path in resorption of the bioresorbable materials, and the resorption period varies depending on the type of polymer. It is important to optimize the type and amount of polymers and calcium phosphate in order to achieve a degradation rate of bioresorbable materials that corresponds to the extent of damage in the healing area. Full article

Aliphatic polyesters, widely used in biomedicine due to their biocompatibility and biodegradability, are typically synthesized via the ring-opening polymerization (ROP) of cyclic esters. Although traditional metal catalysts are highly active, their biological toxicity limits their applications. Organocatalysts, particularly natural organic molecules, offer safer alternatives. We explored the ROP mechanisms of cyclic esters (L-Lactide (L-LA), ε-caprolactone (ε-CL), and δ-valerolactone (δ-VL)) catalyzed by phosphonium carboxybetaines (PCBs, (PhR)₃P⁺(CH₂)₂COO⁻, R = H(PCB), F(PCB-F) and OMe(PCB-OMe)) through density functional theory (DFT) computations. The DFT results revealed that the ROP of cyclic esters follows a bifunctional–cooperative activation mechanism, wherein the phosphonium moiety (Ph₃P⁺(CH₂)₂) activates the monomer via an extensive hydrogen-bonding interaction network, and the carboxylate (COO⁻) serves as a proton acceptor to enhance the nucleophilicity of the initiator phenylpropanol (PPA). In contrast, unsubstituted PCB exhibited the lowest energy barrier, being consistent with the highest catalytic activity among PCB derivatives observed experimentally. Moreover, a series of novel PCB derivatives (Ph₃P⁺(CH₂)_nCOO⁻, n = 3–6 (PCB1-PCB4)) were designed by regulating the carbon spacer length, and their catalytic performances were computationally tested. The designed catalyst PCB2 (Ph₃P⁺(CH₂)₄COO⁻) exhibited higher activity for the ROP of L-LA, attributed to providing sufficient flexibility to minimize deformation while improving proton-accepting capability. Similarly, PCB2 also demonstrated superior catalytic activity for δ-VL and the more challenging ε-CL monomer. This work not only clarifies the intrinsic catalytic nature of these zwitterionic organocatalysts, but also provides an effective strategy for the rational design of high-performance, metal-free catalysts for the synthesis of sustainable polyesters. Full article