Search Results (73)

Background: The generation of durable and hemocompatible small-diameter vascular grafts remains a major challenge in current vascular tissue engineering, as clinically available synthetic grafts are lacking hemocompatibility resulting in limited long-term patency. In recent years, fibrin has emerged as a promising scaffold material for various tissue engineering approaches due to its autologous nature, controllable fabrication, and mechanical properties. However, although pivotal for the translation into clinical application, systematic evaluation of hemocompatibility in fibrin-based small-caliber grafts is still missing. Methods: Here, the hemocompatibility of small-diameter fibrin-based grafts with and without heparin coating was compared to the current gold standard for prosthetic small-diameter vessel replacement in the form of heparin-coated ePTFE grafts using the Chandler Loop circulation model with human whole blood. Cell adhesion of thrombocytes, erythrocytes, and leucocytes was compared. Platelet activation, activation of the complement system, and plasmatic coagulation activity were assessed by ELISA analyses for P-Selectin, complement sC5b-9, and thrombin–antithrombin complex, respectively. Scanning electron microscopy (SEM) was performed to evaluate interactions and thrombocyte activation on the luminal graft surfaces. Results: The short-term hemocompatibility of the fibrin-based grafts with respect to the cell-count, activation of the coagulation pathways, and thrombocyte activation was comparable to the heparin-coated synthetic grafts even without heparin coating of the bioartificial grafts. Conclusions: The findings of this early-stage analysis support fibrin as a promising scaffold material for small-diameter vascular tissue engineering. Full article

Objectives: Biobanks collect biological material prospectively for future, yet unspecified research needs. The relationship between collection strategy and actual utilization remains poorly documented, yet understanding usage patterns is critical for resource allocation and planning. We aimed to analyze the time until first use and the utilization rates stratified by collection type and sample material. Methods: We conducted a retrospective analysis of metadata for all submissions (patient sample set per timepoint) deposited in 2019 (n = 13,666 from 56 collections) at the MedUni Wien Biobank. Collections were classified as prospective cohorts (without predefined hypotheses) or dedicated studies. Utilization was assessed at three levels: collections accessed, submissions from which at least one aliquot was requested, and total aliquots distributed. Results: Within 6–7 years, 31/56 collections (55%) were accessed, with 3466/13,666 submissions (25.4%) and 7565 of ~218,000 aliquots (3.5%) utilized. Among accessed collections, 21/35 were prospective cohorts, and 10/21 were dedicated studies. Median submission utilization was 54.2% (Q1–Q3: 25.2–93.1%). Among accessed submissions, conditional median time was 926 days (Q1–Q3: 438–1573). Serum was most frequently requested (24/31 projects). Aliquot requests per submission varied by material: median of 1 aliquot per sample for all materials except for citrate (2) and lithium heparin (5) plasma. Four material types showed no demand: buffy coat, ccfDNA, double-centrifuged citrate plasma, and saliva. Conclusions: The 3.5% aliquot-level utilization rate, numerically below internationally reported 10–20%, reflects metric granularity and the broad aliquoting strategy rather than low sample demand. Material-specific timing and demand patterns provide an evidence base for resource planning in hospital-based biobanks. Full article

Background and Objectives: Tunneled hemodialysis catheters (TDCs) are essential for vascular access in patients with end-stage renal disease (ESRD). This study retrospectively evaluated the clinical outcomes of permanent TDCs placed at a single center, comparing heparin-coated versus non-heparin-coated catheters. Materials and Methods: A total of 189 patients who underwent permanent TDC placement between January 2021 and January 2022 were included. Patients were categorized by catheter type (heparin-coated, n = 80; non-heparin-coated, n = 109). Catheter failure-free survival was analyzed using the Kaplan–Meier method, with arteriovenous fistula creation treated strictly as a censoring event. Multivariable Cox proportional hazards regression was used to identify independent predictors of catheter failure. Results: Complications were significantly more frequent in the non-heparin-coated group (p = 0.004). Catheter exchange was required exclusively in the non-heparin-coated group (p < 0.001). Kaplan–Meier analysis demonstrated significantly longer failure-free catheter survival in the heparin-coated group (restricted mean 49.0 vs. 41.7 months; Log-Rank p < 0.001). On multivariable Cox regression, the complete absence of events in the heparin-coated group yielded a strong protective point estimate (HR = 0.087, 95% CI: 0.004–1.710), rendering individual patient covariates such as INR and age non-significant. Conclusions: Heparin-coated TDCs were associated with significantly longer failure-free survival and lower complication rates compared with non-heparin-coated catheters. Due to the low overall event rate, individual patient-level covariates including INR did not reach statistical significance in the multivariable model. Full article

Surface modification can regulate surface properties through the design of surface structures and chemical compositions. Heparin has good anticoagulant properties and is widely used in the surface modification of blood-contact materials. However, the molecular structure of heparin has often been overlooked in terms of its application and further utilization in the design process. In this study, heparin was grafted onto substrate materials through polydopamine/polyethyleneimine co-deposition coating and connected with cysteine to obtain PP-Hep-Cys. The sulfhydryl content of PP-Hep-Cys reached about 2.06 nmol/cm², and the NO generation was about 0.2415 nmol/cm². In the absence of NO donors, the introduction of heparin contributed to the inhibition of platelets, but when NO donors were added, the inhibition of platelets was caused by the synergistic effect of heparinization and NO generation. In addition, the clotting time of PP-Hep-Cys was significantly prolonged compared with PP, and the hemolysis rate declined to 0.33 ± 0.01%. Regarding the adsorption performance of Cu²⁺, the adsorption capacity of PP-Hep-Cys was higher than that of PP-Hep and PP-Cys, and monolayer adsorption was dominant. Overall, these results indicated that heparin, as a spacer, and cysteine, as a ligand, exerted a synergistic effect on blood compatibility and adsorption. Full article

After implantation in vivo, airway stents are prone to negative biological effects, such as platelet adhesion, aggregation, and blood coagulation, which may lead to vascular occlusion and thrombosis. Therefore, when studying the antithrombotic properties of vascular grafts, it is crucial to construct a fiber film-coated airway stent with antithrombotic properties. In this paper, PTFE/TPU fiber film was prepared by emulsion electrospinning, and heparin aldehyde group was modified to covalently graft with the fiber film to obtain heparin-loaded fiber film (Hep-PT fiber film), and a heparin-loaded PTFE fiber film-coated airway stent (Hep-PT fiber film-coated airway stent) was prepared. Covalent grafting improves the stability of heparin and promotes the long-term stable release of heparin. The loading of heparin increases the fiber nodes between the fiber films, increases the friction between the fibers, and improves the mechanical properties and ability of the fiber film to resist external forces. At the same time, the Hep-PT fiber film-coated airway stent exhibits excellent cytocompatibility, making it an ideal candidate system for airway stent materials. Full article

We evaluated human embryonic stem cell-derived mesenchymal stem cells (ES-MSCs) on collagen scaffolds for meniscus-like neotissue formation and ex vivo repair of human osteoarthritic (OA) meniscal defects. Collagen type I fibrous scaffolds were pneumatospun, and laminate scaffolds were fabricated from electrospun PLA/collagen; crosslinked; heparin conjugated; fibronectin coated; functionalized with TGFβ1, TGFβ3, or PDGFbb; seeded with ES-MSCs; and cultured for 4 weeks, followed by in vitro assessment or ex vivo implantation into 3.5 mm human meniscus defects for 5 weeks. Pneumatospinning generated highly porous scaffolds that supported uniform cell infiltration, while laminate scaffolds demonstrated interlocking fiber interfaces and enhanced mechanical properties. TGFβ1 and TGFβ3 immobilization enhanced scaffold bioactivity, defined as growth factor-mediated increases in meniscus-like matrix deposition, collagen fiber organization, and meniscogenic gene expression, by significantly increasing safranin O staining, collagen type II deposition, collagen fiber polarization, and ACAN expression. TGFβ3 additionally increased COL1A1 expression and pushout shear modulus; TGFβ1 increased peak pushout stress, indicating superior ex vivo mechanical integration. Laminate scaffolds resulted in extensive cell infiltration, robust neotissue formation (elastic modulus ~2.4 MPa), and improved ex vivo tissue integration when functionalized with TGFβ3. The data indicated that ES-MSC-seeded, heparin-conjugated, TGFβ-immobilized pneumatospun/electrospun collagen–PLA scaffolds support meniscogenic differentiation and biomechanical integration, with repair of focal meniscal defects and potential for partial meniscus replacement. Full article

The coagulation cascade triggered by the contact between blood and the surface of implantable/interventional devices can lead to thrombosis, severely compromising the long-term safety and efficacy of medical devices. As an alternative to systemic anticoagulants, surface anticoagulant modification technology can achieve safer hemocompatibility on the device surface, holding significant potential for clinical application. This article systematically elaborates on the latest research progress in the surface anticoagulant modification of blood-contacting materials. It analyzes and discusses the main strategies and their evolution, spanning from physically inert carbon-based coatings and heparin-based drug-functionalized surfaces to hydrophilic/hydrophobic dynamic physical barriers, biologically signaling regulatory coatings, and bio-integrative/regenerative endothelium-mimicking surfaces. The advantages and limitations of the respective methods are outlined, and the potential for synergistic application of multiple strategies is explored. A special emphasis is placed on current research hotspots regarding novel anticoagulant surface technologies, such as hydrogel coatings, liquid-infused surfaces, and 3D-printed endothelialization, aiming to provide insights and references for developing long-term, safe, and hemocompatible cardiovascular implantable devices. Full article

Recently, interest in multifunctional materials has increased; therefore, we developed a system that combines biocompatibility, gradient changing, and antibacterial properties. We aim to combine these properties in the development of a biomimetic system based on hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, HA) by incorporating silver nanoparticles (Ag NPs) into HA matrices, leveraging their antimicrobial effects, while also exploring their role as drug-release triggers (which absorb infrared (IR) light of 808–960 nm, convert it to heat energy to induce localized heating, and cause a structural leak for drug release) to unmodified HA, which cannot be activated by IR in significant amounts. Limited diffusion aggregation is used to form HA (enhanced with glycine or produced with different outer electrolytes) by diffusing calcium phosphates through Na₂HPO₄-agar. The composite is then packed with tetracycline and a deposition of polyelectrolytes (PE). The combination of polydiallyldimethylammonium chloride (PDADMAC) and heparin forms a robust PE. Infrared light (808 nm, 1.4 mW/cm²) was utilized as energy source for non-invasive and on-demand drug release. Physical and chemical characterization of HA was carried out. Glycine did not affect the p-factor of the resulting rings, which is equal to ca. 1.00. NIR increased release rates 2.1-fold (k = 39.21 compared to 18.22). High glycine concentrations reduce HA crystallinity (94 to 30%), result in a 12.5% increased drug-loading capacity, and increase solubility (5× control). NIR reduced the Korsmeyer–Peppas release exponent (n) from 0.42 (Fickian) to 0.11 (PE-coated HA-Ag), confirming the photothermal disruption of diffusion barriers due to the presence of silver nanoparticle peaks in the composition. Full article

Polymeric micelles are widely studied as nanocarriers for hydrophobic drugs, yet their structural stability under physiological conditions remains a major limitation. This review provides a comparative evaluation of synthetic and natural polymeric micelles with a focus on their stability under dilution and in protein-rich environments. The discussion integrates thermodynamic and kinetic factors governing micelle integrity and examines how molecular composition, hydrophobic segment length, and core–shell modifications influence disintegration behavior. While synthetic micelles commonly collapse below their critical micelle concentration during intravenous administration, natural polymeric micelles, such as those derived from chitosan, alginate, or heparin, exhibit improved resistance to dilution but remain vulnerable to protein-induced destabilization. Strategies such as core or shell cross-linking, surface functionalization, and natural polymer coatings are reviewed as promising approaches to enhance circulation stability and controlled drug release. The work provides a framework for designing micellar systems with balanced biocompatibility, biodegradability, and robustness suitable for clinical drug-delivery applications. Full article

Ophthalmic lens coatings are increasingly designed to combine optical, mechanical, and biological functions. This systematic review, registered in PROSPERO and conducted according to PRISMA 2020 guidelines, synthesized 54 experimental, preclinical, and clinical studies on coatings for spectacle lenses, contact lenses, and intraocular lenses. Spectacle lens studies consistently showed that anti-reflective and blue-light filtering coatings reduce glare perception, improve contrast sensitivity, and provide UV protection, while laboratory tests demonstrated significant reductions in impact resistance, with fracture energy of CR-39 lenses decreasing by up to 63% when coated. Contact lens research revealed that plasma and polymeric coatings reduce water contact angles from >100° to <20°, enhancing wettability, while antimicrobial strategies such as melamine binding or nanoparticle-based films achieved >80% reductions in bacterial adhesion. Drug-eluting approaches sustained antibiotic or antioxidant release for periods ranging from 24 h to 6 days, with improved ocular bioavailability compared with drops. Intraocular lens studies demonstrated that heparin surface modifications reduced postoperative flare and anterior chamber cells, and phosphorylcholine or alkylphosphocholine coatings suppressed lens epithelial cell proliferation. Drug-loaded coatings with methotrexate, gefitinib, or amikacin significantly inhibited posterior capsule opacification and infection in ex vivo and animal models. Collectively, coatings improve visual comfort, photoprotection, wettability, and biocompatibility, but clinical translation requires solutions to mechanical trade-offs, long-term stability, and regulatory challenges. Full article

Bioabsorbable scaffolds from synthetic polyesters are widely used in the field of tissue engineering. However, their hydrophobic surface and lack of suitable functional groups are the main limitations related to cell attachment. The aim of this research was to modify the surface of polycaprolactone (PCL) scaffolds using a bioactive coating containing heparin bound via albumin spacer and platelet lysate over heparin. Porous scaffolds were produced by electrospinning from 10% PCL (w/w) solution in methylene chloride (25 kV voltage, 100 mm distance between electrodes and 4 mL/h feedrate), which demonstrated 5.5 ± 1.1 MPa Young’s modulus, 2.5 ± 0.4 MPa tensile strength and 321 ± 29% elongation at break. Bioactive coating does not change the structure and mechanical properties of the scaffolds. Treated scaffolds are biocompatible and have no cytotoxic effect in direct contact with cells. Functionalization also promotes the in vitro adhesion and proliferation of human adipose mesenchymal stromal cells. After 7 days of incubation, the PCL scaffold modified with the heparin–platelet lysate complex had a cell density of 185.6 ± 15.7 cells/mm² compared to 79.5 ± 7.8 cells/mm² for nontreated control. The intramuscular implantation of scaffolds revealed that immobilization of heparin alone prolongs the acute phase of the inflammatory reaction. However, subsequent treatment with platelet lysate minimizes the inflammatory reaction, slows the rate of implant absorption, and accelerates vascularization. The results obtained show that the developed bioactive coating improves the cellular properties of PCL electrospun scaffolds and can be used to form in vivo tissue-engineered constructs. Full article

Background: Blood collection tubes (BCTs) are critical in vitro diagnostic devices used in clinical laboratory testing. Innomed tubes are novel BCTs coated with heparin and anti-glycolytic agents (Innomed 1) and clot activators combined with anti-glycolytic agents (Innomed 2). This study, we focus on the verification and multicenter validation of Innomed tubes, aiming to assess their performance in glucose stability, hemolysis resistance, and biochemical interferences relevant to diabetes and non-communicable disease (NCD) monitoring. Methods: Two types of Innomed tubes were evaluated. The verification process, conducted in a reference laboratory, assessed biochemical interferences, glucose stability, and the potential for hemolysis due to centrifugation and blood collection techniques. The multicenter validation of biochemical interferences was carried out across five hospital laboratories. Subsequently, samples were centrifuged at 3500 rpm for 5–10 min and analyzed immediately after separation, not exceeding 2 h from collection. Results: Glucose levels in Innomed 1 and 2 remained stable within 8% of up to 8 h post-collection. No hemolysis was observed under varying centrifugation times (at 3500 rpm) and blood collection techniques, as confirmed through visual inspection and lactate dehydrogenase level determinations. Innomed tubes were suitable BCTs for glucose, HbA1c, thyroid stimulating hormone, free triiodothyronine, free thyroxin, triiodothyronine, carcinoembryonic antigen, and prostate-specific antigen, as well as for 19 routine biochemical assays. Conclusions: Innomed 1 and 2 BCTs maintain blood glucose stability for 8 h, ensuring accurate biochemical, HbA1c, thyroid, and tumor marker testing. Their hemolysis resistance supports diabetes screening and Non-Communicable Diseases (NCD) monitoring. thereby emphasizing their clinical relevance in chronic disease management. Full article

Electroactive biomaterials are a key emerging technology for the treatment of neural damage. Conducting polymer-coated carbon microfibers are particularly useful for this application because they provide directional support for cell growth and tissue repair and simultaneously allow for ultrasensitive recording and stimulation of neural activity. Here, we report in vitro experiments investigating the biology of Schwann cells (SCs), a major player in peripheral nerve regeneration, on electroconducting microfibers. The optimal molecular composition of the cell substrate and cell culture medium was studied for SCs dissociated from rat and pig peripheral nerves. The substrate molecules were then attached to carbon microfibers coated with poly (3,4-ethylenedioxythiophene) doped with poly [(4-styrenesulfonic acid)-co-(maleic acid)] (PCMFs), which served as an electroactive scaffold for culturing nerve explants. Biphasic electrical stimulation (ES) was applied through the microfibers, and its effects on cell proliferation and migration were assessed in different cell culture media. Rodent and porcine SCs avidly migrated on PCMFs functionalized with a complex of poly-L-lysine, heparin, basic fibroblast growth factor, and fibronectin. Serum and forskolin/heregulin increased, by two-fold and four-fold, the number of SCs on PCMFs, respectively, and ES further doubled cell numbers without favoring fibroblast proliferation. ES additionally increased SC migration. These results provide a baseline for using biofunctionalized PCMFs in peripheral nerve repair. Full article

Extracorporeal membrane oxygenation (ECMO) is a crucial life support therapy for patients with severe cardiac and respiratory failure. However, the complications associated with venoarterial ECMO (VA-ECMO), including thrombus formation, bleeding, and hemolysis, remain significant challenges that impact patient outcomes and healthcare costs. These complications primarily arise from blood–material interactions within the ECMO circuit, necessitating the development of biocompatible materials to optimize hemocompatibility. This review provides an updated overview of the latest advancements in VA-ECMO materials, focusing on cannula, oxygenators, and centrifugal pumps. Various surface modifications, such as heparin coatings, nitric oxide-releasing polymers, phosphorylcholine (PC)-based coatings, and emerging omniphobic surfaces, have been explored to mitigate thrombosis and bleeding risks. Additionally, novel oxygenator membrane technologies, including zwitterionic polymers and endothelial-mimicking coatings, offer promising strategies to enhance biocompatibility and reduce inflammatory responses. In centrifugal pumps, magnetic levitation systems and hybrid polymer-composite impellers have been introduced to minimize shear stress and thrombogenicity. Despite these advancements, no single material has fully addressed all complications, and further research is needed to refine surface engineering strategies. This review highlights the current progress in ECMO biomaterials and discusses future directions in developing more effective and durable solutions to improve patient safety and clinical outcomes. Full article

Due to the limited regeneration of cartilage, new implant materials are needed. Biodegradable polymers poly-(D,L)-lactide-ε-caprolactone-methacrylate (LCM) and polyamid-ε-caprolactone-methacrylate (ACM) were recently established and coated with heparin, making them able to prevent blood coagulation and cartilage mineralization. The aim of this study was to analyze the suitability of LCM and ACM alone or coated with heparin (the latter are abbreviated as LCMH and ACMH, respectively) as implant material for cartilage repair. Therefore, mesenchymal stem cells were chondrogenically differentiated in 2D cultures with polymer discs. Differentiation was induced by the supplementation of cell medium with dimethyloxalylglycine, TGF-β, and BMP2. After 5 days, no increase in proinflammatory factors was observed. Cell viability declined on ACM and ACMH discs. During early chondrogenesis, SOX9 expression increased on LCM and LCMH discs, while TRPV4 expression decreased on ACMH discs. At day 20, the level of collagen type II increased on LCM, LCMH, and ACM discs, demonstrating the ability of chondrogenic development on these implants. In summary, coating with heparin showed no advantages compared to pure LCM and ACM. For cartilage repair, LCM is more suitable than ACM in this 2D in vitro model, which needs to be verified by long-term 3D models and in vivo studies. Full article