Self-supporting films from amphiphilic hyaluronan are suitable for medical applications like wound dressings or resorbable implants. These films are typically cast from water/alcohol solutions. However, when the mixed solvent evaporates in ambient air, convection flows develop in the solution and become imprinted in the film, potentially compromising its properties. Consequently, we developed a novel film manufacturing method: drying in a closed box under saturated vapour conditions. Using this approach, we prepared a series of optically clear lauroyl-hyaluronan (LHA) films with uniform thickness and compared them to their air-dried counterparts. We first evaluated swelling ratios and elastic moduli for LHA films with varying degrees of substitution. The box-dried films swelled significantly less and were 1-2 orders of magnitude stiffer than air-dried films from the same LHA sample. Confocal microscopy revealed that box-dried films exhibited a regular microstructure, while air-dried films displayed a pore-size gradient and strong microstructure modulation due to convection flows. Local elastic modulus variations arising from these microstructures were assessed using nanoindentation mapping. Importantly, achieving the desired film stiffness requires much lower polymer modification when box-drying is used, enhancing the biological response to the material. These findings have implications for all polysaccharide formulations that utilize mixed solvents.
- Klíčová slova
- Film, Hyaluronan, Hydrogel, Microstructure, Mixed solvent, Nanoindentation, Solution casting,
- Publikační typ
- časopisecké články MeSH
The objective of this study is to develop a reliable tribological model to enable a more thorough investigation of the frictional behavior of fascia tissues connected to non-specific lower back pain. Several models were designed and evaluated based on their coefficient of friction, using a low-frequency, low-load reciprocating motion. The study found that two technical elastomers, layered on PDMS to simulate the fascia and underlying muscle, are suitable substitutes for biological tissue in the model. The influence of tribopair geometry was also examined, and the results showed that greater conformity of contact leads to a lower COF, regardless of the material combination used. Finally, the friction properties of HA of various molecular weights and concentrations were tested.
- Klíčová slova
- Fascia, Friction test, Hyaluronic acid, Soft material, Tribological model,
- MeSH
- biologické modely MeSH
- biomechanika MeSH
- dimethylpolysiloxany chemie MeSH
- elastomery chemie MeSH
- fascie * fyziologie MeSH
- testování materiálů * MeSH
- tření * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- baysilon MeSH Prohlížeč
- dimethylpolysiloxany MeSH
- elastomery MeSH
Nanofibrous materials represent a very promising form of advanced carrier systems that can be used industrially, especially in regenerative medicine as highly functional bandages, or advanced wound dressings. By incorporation of antimicrobial additives directly into the structure of the nanofiber carrier, the functionality of the layer is upgraded, depending on the final requirement-bactericidal, bacteriostatic, antiseptic, or a generally antimicrobial effect. Such highly functional nanofibrous layers can be prepared mostly by electrospinning technology from both synthetic and natural polymers. The presence of a natural polymer in the composition is very advantageous. Especially in medical applications where, due to the presence of the material close to the human body, the healing process is more efficient and without the occurrence of an unwanted inflammatory response. However, converting natural polymers into nanofibrous form, with a homogeneously distributed and stable additive, is a great challenge. Thus, a combination of natural and synthetic materials is often used. This review clearly summarizes the issue of the incorporation and effectiveness of different types of antimicrobial substances, such as nanoparticles, antibiotics, common antiseptics, or substances of natural origin, into electrospun nanofibrous layers made of mostly natural polymer materials. A section describing the problematic aspects of antimicrobial polymers is also included.
- Klíčová slova
- antiseptics, bandage, chitosan, electrospinning, hyaluronic acid, nanofibers, nanoparticles, wound healing,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Hyaluronan (HA) has been recently identified as a key component of the densification of thoracolumbar fascia (TLF), a potential contributor to non-specific lower back pain (LBP) currently treated with manual therapy and systemic or local delivery of anti-inflammatory drugs. The aim of this study was to establish a novel animal model suitable for studying ultrasound-guided intrafascial injection prepared from HA with low and high Mw. Effects of these preparations on the profibrotic switch and mechanical properties of TLF were measured by qPCR and rheology, respectively, while their lubricating properties were evaluated by tribology. Rabbit proved to be a suitable model of TLF physiology due to its manageable size enabling both TLF extraction and in situ intrafascial injection. Surprisingly, the tribology showed that low Mw HA was a better lubricant than the high Mw HA. It was also better suited for intrafascial injection due to its lower injection force and ability to freely spread between TLF layers. No profibrotic effects of either HA preparation in the TLF were observed. The intrafascial application of HA with lower MW into the TLF appears to be a promising way how to increase the gliding of the fascial layers and target the myofascial LBP.
- Klíčová slova
- Hyaluronan, Intrafascial injection, Thoracolumbar fascia,
- MeSH
- fascie * fyziologie MeSH
- králíci MeSH
- kyselina hyaluronová * MeSH
- modely u zvířat MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- kyselina hyaluronová * MeSH
This study investigated the impact of carbonaceous fillers (carbon black, multiwalled carbon nanotubes, graphene, and highly defective graphene) on aromatic and nonaromatic photopolymer resins' properties, such as viscosity, long-term stability, complex permittivity, curing efficiency, final conversion, storage modulus, heat deflection and glass transition temperatures, network density, and DC resistivity. The presented results also highlight challenges that must be addressed in designing and processing carbonaceous filler-based 3D-printed photopolymer resins. The improved dielectric and electrical properties were closely tied to the dispersion quality and filler-matrix affinity. It favored the enhanced dispersion of anisotropic fillers (nanotubes) in a compatible matrix above their percolation threshold. On the other hand, the dispersed filler worsens printability due to the elevated viscosity and deteriorated penetration depth. Nonetheless, electrical and rheological percolation was found at different filler concentrations. This window of despaired percolation combines highly enhanced conductivity with only mildly increased viscosity and good printability.
- Publikační typ
- časopisecké články MeSH
In this work, amphiphilic hyaluronan was synthesized by grafting succinylated N-oleoyl-phytosphingosine via esters bonds. Succinylated N-oleoyl-phytosphingosine (sCER) was first prepared by esterification of hydroxyl moieties of the ceramide with succinic anhydride. The esterification of hyaluronan was governed by crowding effect. The oligomeric HA-sCER derivatives exhibited a strong self-aggregation as evidenced by a very low critical aggregation concentration (1.9 μg mL-1), higher pyrene binding constant (KB), and the smallest particle size (30 nm) in solution. The self-aggregation properties demonstrated to be a function of the substitution degree and molecular weight of HA. The prepared derivatives were non-cytotoxic towards cell lines NIH-3T3. Nanoparticles prepared using oligomeric HA-sCER derivatives improved the penetration of Nile red dye through the stratum corneum due to their smaller size (≤50 nm). The fluorescence intensity localized at the stratum corneum was higher for oligomeric HA-sCER. A significant inhibition of the pro-inflammatory cytokine interleukin-6 production was observed in vitro in macrophages differentiated from THP-1 cells. These findings showed that HA-sCER constituted a promising active ingredient for cosmetics use.
- Klíčová slova
- Amphiphilic polysaccharides, Ceramides, Hyaluronan, IL-6, Self-assembling, Skin penetration,
- MeSH
- ceramidy MeSH
- esterifikace MeSH
- kyselina hyaluronová * MeSH
- lékové transportní systémy * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- ceramidy MeSH
- kyselina hyaluronová * MeSH
- phytosphingosine MeSH Prohlížeč
The negative impact of cigarette smoking on the skin includes accelerated aging, pigmentation disorders, and impaired wound healing, but its effect on the skin barrier is not completely understood. Here, we studied the changes in selected epidermal proteins and lipids between smokers (45-66 years, smoking > 10 years, > 10 cigarettes per day) and non-smokers. Volar forearm epidermal and stratum corneum samples, obtained by suction blister and tape stripping, respectively, showed increased thickness in smokers. In the epidermis of smokers, we observed a significant upregulation of filaggrin, loricrin, and a trend of increased involucrin but no differences were found in the case of transglutaminase 1 and kallikrein-related peptidase 7, on the gene and protein levels. No significant changes were observed in the major skin barrier lipids, except for increased cholesterol sulfate in smokers. Liquid chromatography coupled with mass spectrometry revealed shorter acyl chains in ceramides, and an increased proportion of sphingosine and 6-hydroxysphingosine ceramides (with C4 trans-double bond) over dihydrosphingosine and phytosphingosine ceramides in smokers, suggesting altered desaturase 1 activity. Smokers had more ordered lipid chains found by infrared spectroscopy. In conclusion, cigarette smoking perturbs the homeostasis of the barrier proteins and lipids even at a site not directly exposed to smoke.
A cascade of reactions known as the foreign body response (FBR) follows the implantation of biomaterials leading to the formation of a fibrotic capsule around the implant and subsequent health complications. The severity of the FBR is driven mostly by the physicochemical characteristics of implanted material, the method and place of implantation, and the degree of immune system activation. Here we present an in vitro model for assessing new materials with respect to their potential to induce a FBR in the peritoneum. The model is based on evaluating protein sorption and cell adhesion on the implanted material. We tested our model on the free-standing films prepared from hyaluronan derivatives with different hydrophobicity, swelling ratio, and rate of solubilization. The proteomic analysis of films incubated in the mouse peritoneum showed that the presence of fibrinogen was driving the cell adhesion. Neither the film surface hydrophobicity/hydrophilicity nor the quantity of adsorbed proteins were decisive for the induction of the long-term cell adhesion leading to the FBR, while the dissolution rate of the material proved to be a crucial factor. Our model thus helps determine the probability of a FBR to materials implanted in the peritoneum while limiting the need for in vivo animal testing.
- Klíčová slova
- Cell adhesion, Fibrinogen, Foreign body reaction, Hyaluronan, Implant, Protein adsorption,
- MeSH
- biokompatibilní materiály farmakologie chemie MeSH
- cizí tělesa * MeSH
- myši MeSH
- peritoneum MeSH
- proteiny MeSH
- proteomika MeSH
- reakce na cizí těleso * chemicky indukované MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- biokompatibilní materiály MeSH
- proteiny MeSH
Hyaluronan (HA) is a naturally occurring polysaccharide widely used in medicine and cosmetics. To further broaden its potential, various HA derivatives have been developed with the aim of reducing solubility, slowing degradation, or providing other beneficial properties. However, for most medical applications, these derivatives must be processed into suitable forms. Here we present water-insoluble fibres prepared from lauroyl-modified HA using a wet spinning process. Important properties of the fibres, such as swelling or the degradation rate, can be fine-tuned by adjusting the degree of HA modification. Due to their mechanical properties, the lauroyl HA fibres can be easily processed into threads and subsequently into fabrics of various sizes, shapes, and degrees of porosity. In addition, in vitro cytotoxicity testing of the fibres showed that they were non-cytotoxic. Overall, our results suggest that lauroyl HA fibres are a promising material that could be used to develop a variety of medical devices.
- Klíčová slova
- Fibre, Lauroyl hyaluronan, Wet spinning,
- MeSH
- kyselina hyaluronová * metabolismus MeSH
- poréznost MeSH
- voda * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- kyselina hyaluronová * MeSH
- voda * MeSH
Hyaluronan (HA) is a natural polysaccharide occurring ubiquitously in the connective tissues of vertebrates widely used in the cosmetic and pharmaceutic industries. In numerous applications HA oligosaccharides are being chemically modified using reactions incompatible with aqueous solutions, often carried out in water:organic mixed solvents. We carry out molecular-dynamics (MD) simulations of HA oligosaccharides in water:1,4-dioxane and water:tert-butanol mixtures of different compositions. HA molecule causes a separation of the solvent components in its surroundings, especially in tert-butanol containing solutions, constituting thus a solvation shell enriched by water. Furthermore, interactions with ions are stronger than in pure water and depend on the solvent composition. Consequently, the dynamics of the HA chain varies with the solvent composition and causes observable conformational changes of the HA oligosaccharide. Composition of mixed solvents thus enables us to modify the interaction of HA with other molecules as well as its reactivity.
- Klíčová slova
- 1,4-Dioxane, Hyaluronan, Mixed solvent, Molecular dynamics, Solvent separation, Tert-butanol,
- MeSH
- kyselina hyaluronová * MeSH
- oligosacharidy MeSH
- rozpouštědla chemie MeSH
- terc-butanol MeSH
- voda * chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- kyselina hyaluronová * MeSH
- oligosacharidy MeSH
- rozpouštědla MeSH
- terc-butanol MeSH
- voda * MeSH
