Pokročilé biomateriály

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Investigating the effects of laser wavelengths and other ablation parameters on the detection of biogenic elements and contaminants in hydroxyapatite
(ROYAL SOC CHEMISTRY, 2024-08-28) Fazlić, Aida; Faruzelová, Anna; Buday, Jakub; Michlovská, Lenka; Vojtová, Lucy; Modlitbová, Pavlína; Pořízka, Pavel; Kaiser, Jozef
The main purpose of this work is to thoroughly describe sensitivity and resolution enhancement by systematically optimizing key parameters in laser-induced breakdown spectroscopy analysis. Simultaneous analysis of biogenic (C, P, Mg, and Ca) and contaminating (Pb) elements, which are commonly detected in selected biotic matrices (mammal teeth), was performed. Hydroxyapatite reference pellets were utilized as model matrices, which successfully reflect human dental tissue. The optimization involved precise adjustments of the used laser wavelengths (1064, 532, and 266 nm), relative defocus of the laser pulse, ablation pulse energies, and gate delays for collecting characteristic spectra. In addition, for Ca analysis, the signals of different ionization line types (Ca I 364.44 nm; Ca II 370.60 and 396.85 nm) were compared; in the case of Pb analysis, the limits of detection were established for each used laser wavelength, and the revealed differences were discussed in detail. We intend to demonstrate the benefits of rapid, low-cost analysis and also the importance of measurement parameters used in biotic sample testing. A comparison of laser ablation measurement parameters (laser wavelength, energy, gate delay, defocus, and spot size) to determine optimal settings for the detection of heavy metals and biogenic elements in a hard tissue matrix (hydroxyapatite).
The effect of surface roughness and wettability on the adhesion and proliferation of Saos-2 cells seeded on 3D printed poly(3-hydroxybutyrate)/polylactide (PHB/PLA) surfaces
(Elsevier, 2024-08-01) Melčová, Veronika; Krobot, Štěpán; Šindelář, Jan; Šebová, Eva; Klusáček Rampichová, Michala; Přikryl, Radek
The aim of this work is to explore the effect of surface characteristics of the 3D printed scaffolds on their suitability for Saos-2 cells growth. Two promising materials for bone tissue engineering were examined, both containing poly(3-hydroxybutyrate)/poly(d,l-lactide) plasticized blend and one of them filled with bioactive tricalcium phosphate. The surface free energy (SFE) of samples was determined by contact angle measurement with four liquids. For non-filled sample the water contact angle (WCA) was 74° and its SFE was 40 mNm1. The composite sample exhibited substantially decreased WCA, 61°. Moreover, the addition of the tricalcium phosphate caused doubling of the polar component of the SFE which increased by a total of 13%. 3D printed surfaces prepared by fused deposition modeling method showed a profound increase of WCA due to the increase in their surface roughness which was analyzed by confocal microscopy. The change in wetting properties strongly affected the behavior of Saos-2 cells on printed surfaces. The number of cells as measured by DNA quantification linearly decreased with increasing surface WCA. The highest number of cells was observed on the pressed samples and 3D printed surfaces made of simple lines and a grid with 50 m gap between lines. The favored surfaces exhibit WCA under 80° which is important information for the future design of the scaffolds.
Liposomes Affect Protein Release and Stability of ITA-Modified PLGA-PEG-PLGA Hydrogel Carriers for Controlled Drug Delivery
(AMER CHEMICAL SOC, 2023-12-22) Kadlecová, Zuzana; Sevriugina, Veronika; Lysáková, Klára; Rychetský, Matěj; Chamradová, Ivana; Vojtová, Lucy
Fat grafting, a key regenerative medicine technique, often requires repeat procedures due to high-fat reabsorption and volume loss. Addressing this, a novel drug delivery system uniquely combines a thermosensitive, FDA-approved hydrogel (itaconic acid-modified PLGA-PEG-PLGA copolymer) with FGF2-STAB, a stable fibroblast growth factor 2 with a 21-day stability, far exceeding a few hours of wild-type FGF2's stability. Additionally, the growth factor was encapsulated in "green" liposomes prepared via the Mozafari method, ensuring pH protection. The system, characterized by first-order FGF2-STAB release, employs green chemistry for biocompatibility, bioactivity, and eco-friendliness. The liposomes, with diameters of 85.73 +/- 3.85 nm and 68.6 +/- 2.2% encapsulation efficiency, allowed controlled FGF2-STAB release from the hydrogel compared to the unencapsulated FGF2-STAB. Yet, the protein compromised the carrier's hydrolytic stability. Prior tests were conducted on model proteins human albumin (efficiency 80.8 +/- 3.2%) and lysozyme (efficiency 81.0 +/- 2.7%). This injectable thermosensitive system could advance reconstructive medicine and cosmetic procedures.
A synergistic effect of fibrous carboxymethyl cellulose with equine collagen improved the hemostatic properties of freeze-dried wound dressings
(Springer Nature, 2023-08-23) Sedlář, Marian; Verčimáková, Katarína; Fohlerová, Zdenka; Izsák, Dávid; Chalupová, Marta; Suchý, Pavel; Dohnalová, Marcela; Sopuch, Tomáš; Vojtová, Lucy
Bleeding is one of the most commonly occurring injuries; it can be painful and even life-threatening condition. The hemostats are substances that promote blood clotting and fasten hemostasis. In this paper, we evaluated the hemostatic effect of freeze-dried wound dressings based on equine collagen, porcine collagen, fibrous carboxymethyl cellulose (CMC) and their mixtures. The wound dressings were investigated for their morphological structure, chemical structure, absorption properties, in vitro hemostasis, cytotoxicity assay and lastly, for in vivo hemostasis. We have found out that adding fibrous CMC into collagen-based hemostatic wound dressings creates a strong synergistic effect, which significantly improves absorption capacity by almost doubling it, as well as supports clotting time. Based on the in vivo studies on partial nephrectomy in rats, the time needed for achieving hemostasis was significantly lower due to the synergy of collagen and CMC. Our materials were compared to the commonly used hemostatic sealing patch on the market (Tachosil) during the in vivo testing, and sample of a mixture of equine collagen and CMC showed better hemostatic efficacy.
Antimicrobial Cost-Effective Transparent Hydrogel Films from Renewable Gum Karaya/Chitosan Polysaccharides for Modern Wound Dressings
(American Chemical Society, 2023-04-14) Drápalová, Eva; Michlovská, Lenka; Poštulková, Hana; Chamradová, Ivana; Lipový, Břetislav; Holoubek, Jakub; Vacek, Lukáš; Růžička, Filip; Hanslianová, Markéta; Svobodová, Táňa; Černá, Eva; Hrdličková, Barbara; Vojtová, Lucy
The newest trends in wound healing management and the development of the next generation of dressings are pointing toward natural polymeric materials with important beneficial properties such as antimicrobial effects, renewability, easier process of preparation, and biological activity. Here, we present the preparation and in vitro evaluation of a unique biopolymeric blend composed of natural polymers based on the positively charged polysaccharide chitosan and negatively charged gum karaya. A plate lysis assay of gum karaya and chitosan solution mixtures proved the synergistic antimicrobial effect against specific strains of both Gram-positive and Gram-negative bacteria and yeast. This polymeric mixture was used for hydrogel film preparation and determination of the composition effect on physical properties (swelling behavior in different solvents, pH, diffusion mechanism, hydrolytic stability, mechanical and optical properties). While the pure gum karaya with poly(vinyl alcohol) exhibited the highest hydrolytic degradation (68%), the mixture of poly(vinyl alcohol) and gum karaya with chitosan (in the 25:75 ratio) exhibited the lowest degradation value (41%) due to the strong physical interactions. Cytotoxicity tests performed with hydrogel extracts using two different in vitro models, adherent fibroblasts (NIH3T3) and non-adherent suspension B-lymphocytes (BaF3), exhibited excellent biocompatibility and no cytotoxicity. As expected, the antimicrobial activity of 3-day film extracts showed a significantly improved antimicrobial effect of mixtures involving a chitosan biopolymer. The physical and biological properties of prepared biopolymer-based hydrogels meet the requirements of modern wound dressings.

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