Iskanje po katalogu digitalne knjižnice

Opis: Polyester biomaterials play a crucial in vascular surgery, but suffer from unspecific protein adsorption, thrombogenicity, and inadequate endothelial cell response, which limit their success. To address these issues, we investigated the functionalization of polyester biomaterials with antithrombogenic polysaccharide coatings. A two-step and water-based method was used to coat cationized polycaprolactone with different sulfated polysaccharides (SPS), which resulted in long-term stability, tunable morphology, roughness, film thickness, chemical compositions, zeta potential, and water content. The coatings significantly increased the anticoagulant activity and reduced the thrombogenicity of polycaprolactone, particularly with highly sulfated heparin and cellulose sulfate. Less SPS, such as chondroitin sulfate, fucoidan, and carrageenan, despite showing reduced anticoagulant activity, also exhibited lower fibrinogen adsorption. The adhesion and viability of human primary endothelial cells cultured on modified polycaprolactone correlated with the type and sulfate content of the coatings.
Ključne besede: polyester biomaterials, vascular surgery, antithrombogenic polysaccharide coatings
Objavljeno v DKUM: 10.09.2024; Ogledov: 65; Prenosov: 10
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Opis: Medical implant-associated infections resulting from biofilm formation triggered by unspecific protein adsorption arethe prevailing cause of implant failure. However, implant surfaces rendered with multifunctional bioactive nanocoatings offer apromising alternative to prevent the initial attachment of bacteria and effectively interrupt biofilm formation. The need to researchand develop novel and stable bioactive nanocoatings for medical implants and a comprehensive understanding of their properties incontact with the complex biological environment are crucial. In this study, we developed an aqueous stable and crosslinker-freepolyelectrolyte−surfactant complex (PESC) composed of a renewable cationic polysaccharide, chitosan, a lysine-based anionicsurfactant (77KS), and an amphoteric antibiotic, amoxicillin, which is widely used to treat a number of infections caused by bacteria.We successfully introduced the PESC as bioactive functional nanolayers on the“model”and“real”polydimethylsiloxane (PDMS)surfaces under dynamic and ambient conditions. Besides their high stability and improved wettability, these uniformly depositednanolayers (thickness: 44−61 nm) with mixed charges exhibited strong repulsion toward three model blood proteins (serumalbumin,fibrinogen, andγ-globulin) and their competitive interactions in the mixture in real-time, as demonstrated using a quartzcrystal microbalance with dissipation (QCM-D). The functional nanolayers with a maximum negative zeta potential (ζ:−19 to−30mV at pH 7.4), water content (1628−1810 ng cm−2), and hydration (low viscosity and elastic shear modulus) correlated with themass, conformation, and interaction nature of proteins. In vitro antimicrobial activity testing under dynamic conditions showed thatthe charged nanolayers actively inhibited the growth of both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcusaureus) bacteria compared to unmodified PDMS. Given the ease of fabrication of multifunctional and charged biobased coatingswith simultaneous protein-repellent and antimicrobial activities, the limitations of individual approaches could be overcome leadingto a better and advanced design of various medical devices (e.g., catheters, prosthetics, and stents).
Ključne besede: silicone implants, protein-repellent, antimicrobial, chitosan, lysine, bioactive coatings, adsorption, QCM-D
Objavljeno v DKUM: 15.04.2024; Ogledov: 266; Prenosov: 16
Celotno besedilo (4,24 MB)
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Opis: In this work, the ability of polyvinylpyrrolidone (PVP)-stabilised gold nanoparticle (AuNP) coatings to inhibit blood protein adsorption was evaluated by studying timeresolved solid–liquid interactions of the coatings with the model blood protein bovine serum albumin (BSA). Inhibiting unspecific blood protein adsorption is of crucial importance for blood-contacting implant devices, e.g. vascular grafts, stents, artificial joints, and others, as a preventive strategy for bacterial biofilm formation. A quartz crystal microbalance was used in this work to coat the AuNPs on piezoelectric sensors and to follow time-resolved solid–liquid interactions with the proteins. The AuNP coatings were evaluated for their wettability by contact angle measurements, their surface morphology by lightand atomic force microscopy, and their chemical composition by energy-dispersive X-ray spectroscopy. Results revealed a homogeneous distribution of AuNPs on the sensor surface with a dry mass coverage of 3.37 ± 1.46 µg/cm2 and a contact angle of 25.2 ± 1.1°. Solid–liquid interaction studies by quartz crystal microbalance showed a high repellence of BSA from the PVP-stabilised AuNP coatings and the importance of the PVP in the mechanism of repellence. Furthermore, the conformation of the polymer on the coatings as well as its viscoelastic properties were revealed. Finally, the activated partial thrombin time test and fibrinogen adsorption studies revealed that the AuNPs do not accelerate blood coagulation and can partially inhibit the adhesion of fibrinogen, which is a crucial factor in the common blood coagulation cascade. Such AuNPs have the potential to be used in blood-contact medical applications.
Ključne besede: gold nanoparticles, ultrasonic spray pyrolysis, haemocompatibility, protein adsorption, quartz crystal microbalance
Objavljeno v DKUM: 30.01.2024; Ogledov: 377; Prenosov: 33
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Opis: This work investigated the potential of amoxicillin-doped hyaluronic acid/fucoidan multifunctional coatings on medical grade stainless steel as biocompatible, osteointegration enhancing, antimicrobial, and bacterial biofilm inhibiting coatings for orthopedic implants. The coatings were prepared by layer-by-layer spin coating and confirmed by optical contact angle goniometry and infrared spectroscopy. Time-of-flight secondary ion mass spectrometry showed a homogeneous distribution of the individual layers. In contrast, thermal diffusivity, and thermal conductivity measurements by photothermal beam deflection spectrometry showed diffusion of the amoxicillin into the hyaluronic acid and fucoidan layers. In vitro release of amoxicillin showed complete release within one hour, as reflected by the formation of inhibition zones against Staphylococcus aureus and Escherichia coli. Synergistic effects were observed between the hyaluronic acid and amoxicillin in inhibiting S.Aureus biofilm, and between the fucoidan and amoxicillin in improving the antioxidant properties by an ABTS radical scavenging assay. Biocompatibility was determined with human osteoblasts, confirming the potential of such multifunc- tional coatings to enhance the bioactivity of steel-based orthop edic implants.
Ključne besede: orthopedic implant, medical grade stainless steel, amoxicillin, hyaluronic acid, fucoidan, multifunctional coating
Objavljeno v DKUM: 18.08.2023; Ogledov: 588; Prenosov: 106
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Opis: Prekomerna uporaba antibiotikov za zdravljenje infekcij vodi v naraščanje števila odpornih bakterij, kar predstavlja grožnjo javnemu zdravju. Strategije zmanjševanja uporabe temeljijo tudi na preprečevanju nastanka bakterijskega biofilma na površinah medicinskih pripomočkov. Predstavljamo metodo funkcionalizacije silikona z oplaščenjem z naravnimi bioaktivnimi substancami. Na silikon smo kot vezni polimer adsorbirali biopolimer polidopamin, na katerega smo kovalentno vezali karbokismetil hitozan s tiolnimi funkcionalnimi skupinami, ki izkazuje protimikrobne in biofilm-inhibitorne lastnosti. Rezultati karakterizacije so pokazali uspešno kovalentno vezavo karboksimetil hitozana preko tiolnih skupin na polidopamin, kar je pripomoglo k zmanjšanju tvorbe biofilma na površini v primerjavi s fizikalno vezanim karboksimetil hitozanom in neobdelanim silikonom.
Ključne besede: biopolimeri, biofunkcionalizacija, protimikrobnost, polidopamin, karboksimetil hitozan
Objavljeno v DKUM: 20.09.2021; Ogledov: 1074; Prenosov: 84
Celotno besedilo (2,89 MB)