Search Results (510)

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

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

Background: Nerve conduits are used to bridge peripheral nerve defects caused by trauma, iatrogenic injury, or oncologic disruption. Three-dimensional (3D) biomimetic scaffolds for peripheral nerve regeneration have advanced significantly in recent years, driven by improvements in printing technology and neuronal seeding techniques. We report on published designer conduits that can recreate the epineurium, a critical yet challenging-to-manufacture feature of nerve tissue. Methods: A medical librarian conducted a literature search for our systematic review on EMBASE, Web of Science, and PUBMED, following PRISMA guidelines, for articles from January 2010 to January 2026 for the systematic review. Descriptive statistical analysis was performed using Microsoft 365 Suite software. The literature review was conducted using keywords and search terms describing the history and development of 3DP nerve guidance conduits published prior to January 2026. Results: Our search yielded 273 titles, of which 8 were included after full-text review; these studies used 3D printing to generate nerve conduits for preclinical models. Manual data extraction identified studies reporting successful epineurial recreation. The included scaffold materials were polycaprolactone, poly(l-lactide-co-ε-caprolactone), poly(lactic-co-glycolic acid), acrylate resin, and gelatin methacryloyl. In animal model studies, various terms were used to describe the epineurium outer sheath. Despite this variability in nomenclature, many of these reports indicated successful sciatic functional index (SFI) recovery, favorable g-ratios, good durability, high cell viability, and significant neurite elongation at the time of sacrifice. Conclusions: 3DP nerve conduits targeting the epineurium are promising approaches for treating peripheral nerve defects. The constructs promote oriented growth and myelination. Future research on incorporating the epineurium into nerve scaffolds may consider encapsulating NGF to promote more efficient nerve regeneration, standardizing the definition of epineurial recreation, designing mechanical and permeability reporting benchmarks, and evaluating cell strategies using comparable functional and histologic endpoints. Full article

The design of multifunctional biomaterials that offer both structural support and biochemical cues is essential for enhancing tissue regeneration. In this study, hybrid nanofibrous scaffolds composed of poly(L-lactide-co-ε-caprolactone) (PLCL) and bioactive factors secreted by Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) were fabricated via co-electrospinning. Nanofibers were produced in aligned and random configurations following an optimized protocol developed at the Institute for Bioengineering of Catalonia (IBEC). Their morphology and topography were characterized by light microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM), and fiber orientation was quantified via Fast Fourier Transform (FFT) analysis. The scaffolds showed fiber diameters of 542.9 ± 62.3 nm, with aligned fibers predominantly oriented within 20° of the principal axis. Human AD-MSCs were used to assess biocompatibility and cell–material interactions. Aligned and random nanofiber architectures elicited distinct cellular responses. AD-MSCs on aligned fibers exhibited smaller spreading areas (~320 μm²) vs. on random nanofibers (~500 μm²) and substantially higher proliferation, resulting in a shorter cell-doubling time (~25 h) than those on random nanofibers (~130 h) or control substrates (~70 h). In addition, aligned nanofibers promoted markedly faster migration, reaching rates of ~5000 μm²/h surface coverage, compared with random nanofibers (~770 μm²/h) and controls (~1800 μm²/h). Together, the results show that nanofiber alignment and biochemical functionalization jointly influence MSC behavior and improve regeneration, highlighting the potential of these PLCL-based hybrid secretome/PLCL nanofibers for advanced wound healing. Full article

The ability to precisely control the morphology of polylactide (PLA) microparticles is crucial for their biomedical applications, yet it is a challenge due to the interdependent nature of key parameters such as size, porosity, and surface topology. This study presents a systematic approach to fabricating PLA microparticles with tunable architecture via emulsion-solvent evaporation by investigating the interplay of polymer molecular weight (44–442 kDa), solution concentration (0.5–20% w/v), and porogen type (PEG, alkanes, lithium salts). We achieved precise size control from 5 to 500 μm, dictated by solution viscosity and the polymer’s crystallization tendency, with poly(L-lactide) yielding irregular particles and poly(D,L-lactide) forming perfect spheres. Furthermore, porogen selection was critical for porosity: alkanes enabled tailored pore networks, with longer chains (e.g., decane) producing larger pores via enhanced phase separation, whereas the double-emulsion method with Li₂CO₃ proved superior for macroporosity due to its slow leaching kinetics. This work provides a foundational guideline for the rational design of PLA microparticles with customized properties for targeted applications in drug delivery and tissue engineering. Full article

Triacetin (TA) is a solvent commonly used in pharmaceutical and food applications, and as a plasticizer in bioplastics such as poly(lactic acid) (PLA) and cellulose acetate (CA). L-lactide is the monomer used in the ring-opening polymerization of PLA. The structure of TA emulsions stabilized by a cellulose hydrogel (CH) was imaged in this study. The emulsions were prepared by mechanical homogenization or a two-step process with subsequent high-pressure homogenization (HPH). The two-step process yielded smaller TA droplets and a more homogeneous CH dispersion. The images demonstrate that emulsion stabilization is due to CH particles adsorbed at the TA–water interface. The ester hydrolysis of TA and a lactide/TA solution by two industrially important lipases, from Candida rugosa (CRL) and Burkholderia cepacia (BCL), was investigated, assessing the effect of CH as an emulsion stabilizer. Mechanically homogenized TA emulsions were effectively hydrolyzed. Lactide was found to inhibit the enzymatic hydrolysis of TA. This inhibition was mitigated by CH for CRL-catalyzed hydrolysis but not for BCL catalysis. These results indicate a synergistic effect of CH stabilization on the interfacial activation of CRL. Thise effect may also be relevant for the biodegradation of bio-derived plastics and their fibrous cellulose composites. Full article

This study aims to assess the rate and duration of rat brain retention after a single intranasal administration of indocyanine green (ICG) as an aqueous solution or encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles. Near-infrared fluorescence emission of ICG from the brain and visceral organs was measured at 1, 4, and 24 h, as well as at 1 and 2 weeks after administration. It was observed that both ICG formulations stained the olfactory bulbs and brainstem, the latter mainly in the basolateral region of the pons. Reduced staining was observed on day 7 after treatment, and the signal remains detectable on day 14. Additionally, while emission from ICG-labeled brains in water decreased after two weeks compared to day 7, in ICG-loaded nanoparticles, the emission was significantly higher on day 14. It is concluded that ICG is transported into the brain via both nose-to-brain delivery pathways—through and along olfactory or trigeminal nerves—and that ICG is a useful dye for in vivo studies due to its long-lasting emission and low toxicity. Furthermore, the suggested penetration of ICG-encapsulated PLGA nanoparticles via these transport mechanisms makes them a useful carrier for brain delivery of substances that are rapidly eliminated from circulation or do not cross the blood–brain barrier. Full article

Background/Objectives. This research supports the development of long-acting injectables (LAIs) via in situ gel (ISG) technology by illustrating the influence of drug properties and formulation variables on in vitro drug release (Part 1), and providing an example of a point-to-point in vitro–in vivo correlation (IVIVC) for celecoxib ISGs (Part 2). Methods/Results. Part 1 evaluated the in vitro release (IVR) for ISGs containing 10 mg/g of five model drugs—paracetamol, theophylline, felbinac, indomethacin, and celecoxib—using two different poly(D,L-lactide-co-glycolide) (PLGA) grades with lactide/glycolide ratios (L/G) of 50:50 or 85:15 in N-methyl-2-pyrrolidone (NMP) at polymer/solvent ratios of 30/70% or 40/60% (w/w). The results demonstrated sustained IVR, with approximately 80% of the drug released within 1 to 5 days for the sparingly soluble compounds paracetamol and theophylline ISGs, and within 1.5 to 11 days, 3 to over 20 days, and 19 to 74 days for the slightly soluble compounds felbinac, indomethacin, and celecoxib, respectively. The IVR rate increased with decreasing polymer lipophilicity and concentration and with increasing drug solubility in the IVR medium. In Part 2, the pharmacokinetics of celecoxib ISGs were assessed following subcutaneous (SC) injection in rats. A point-to-point IVIVC was established between the fraction of drug absorbed derived via deconvolution (deconvoluted F_abs) and the fraction dissolved (observed F_diss) obtained in Part 1, based on Korsmeyer–Peppas fitting and release phase-specific scaling. Conclusions. In summary, this research highlights the significant impact of drug solubility, polymer grade, and concentration on the IVR rates of ISGs and provides an example of a point-to-point IVIVC for celecoxib ISGs with varying polymer concentrations and grades, following SC injection in rats. Full article

The development of biodegradable ABA-type triblock copolymers with tailored thermo-mechanical performance requires precise control over polymer architecture and phase behavior. In this study, PLLA-based ABA triblock copolymers were synthesized using two structurally distinct, fully bio-based soft segments: poly(methyl ricinoleate) (PMR) and poly(1,3-propanediol) (PPD). To the best of our knowledge, this is the first report on PLLA triblock copolymers incorporating PMR as a renewable soft middle block. Hydroxyl-terminated PMR and PPD were employed as macroinitiators for the controlled ring-opening polymerization of L-lactide, enabling systematic variation in block composition and molecular weight. Structural characterization confirmed successful block formation, while thermal and mechanical analyses revealed pronounced differences in phase separation and structure–property relationships. Copolymers containing PMR exhibited enhanced phase separation, increased crystallinity of PLLA domains, and significantly improved elongation at break, attributed to the presence of pendant chains in the soft segment. In contrast, PPD-based copolymers showed reduced phase separation and more PLA-like mechanical behavior. These results demonstrate that the chemical architecture of bio-based soft segments plays a decisive role in governing the thermo-mechanical performance of PLLA-based triblock copolymers. Full article

Background: Synthetic vascular scaffolds often exhibit limited mechanical performance and low hydrophilicity, which compromise early vascular integration and increase susceptibility to bacterial colonization. This study developed 3D-printed scaffolds based on poly(L-co-D,L-lactide)–poly(trimethylene carbonate) (PLDLA–TMC) with polyethylene glycol 400 (PEG) to modulate mechanical and interfacial properties and coated with poly(hexamethylene biguanide) (PHMB) to confer antibacterial activity. Methods: PLDLA–TMC scaffolds modified with PEG 400 and coated with PHMB were prepared and systematically characterized to assess their structural, thermal, mechanical, and antimicrobial properties. PHMB coatings (3%, 6%, and 12% w/w in hydroxypropyl methylcellulose, HPMC) were applied and evaluated for drug release, cytotoxicity, and activity against Staphylococcus aureus. Biocompatibility was tested in an endothelial cell and myoblast co-culture. Results: Incorporation of 2% PEG increased the tensile strength from 0.14 ± 0.10 MPa for scaffolds containing 0.5% PEG to 0.79 ± 0.12 MPa and promotes a more elastic scaffold behavior. PHMB at 12% caused cytotoxicity (7.70 ± 0.37% cell viability). The 3% PHMB coating produced a 12.5 ± 0.1 mm inhibition zone but exhibited burst release within 1 h, whereas the 6% coating maintained cell viability (72.95 ± 1.10%), produced a 13.1 ± 0.2 mm inhibition zone, and provided sustained antimicrobial release over 7 days. Scaffolds supported organized adhesion and proliferation of endothelial cells and myoblasts. Conclusions: 3D-printed PLDLA–TMC scaffolds containing 2% PEG and coated with 6% PHMB combined improved mechanical performance, sustained antimicrobial release, antibacterial activity, and biocompatibility in an in vitro vascular model. Full article