Inżynieria tkankowa : nowe narzędzie w rekonstrukcji tkanek

The loss or failure of an organ or tissue is one of the most devastating and costly problems in healthcare. Tissue engineering is a new field that applies the principles of biology, engineering and the life science in the development of functional substitutes for damaged tissue. Regeneration involves the creation of tissue identical to that which has been lost or injured. In contrast, tissue repair restores the damaged area with functional but different tissue. This approach uses two main components: cells and scaffolds. Scaffold development underpins the advancement of tissue engineering. Materials used for scaffold preparation play a major role and have found widespread biomedical applications in the development of synthetic skin substitutes, controlled drug release delivery, artificial tissue and organs, and biosensors. They have numerous advantages, such as biocompatibility, biodegradability, and antibacterial properties. They are safe for human use

Hydrogel membranes based on genipin-cross-linked chitosan blends for corneal epithelium tissue engineering

Novel polymeric hydrogel scaffolds for corneal epithelium cell culturing based on blends of chitosan with some other biopolymers such as hydroxypropylcellulose, collagen and elastin crosslinked with genipin, a natural substance, were prepared. Physicochemical and biomechanical properties of these materials were determined. The in vitro cell culture experiments with corneal epithelium cells have indicated that a membrane prepared from chitosan–collagen blend (Ch–Col) provided the regular stratified growth of the epithelium cells, good surface covering and increased number of the cell layers. Ch–Col membranes are therefore the most promising material among those studied. The performance of Ch–Col membranes is comparable with that of the amniotic membrane which is currently recommended for clinical applications

Corneal epithelial scaffolds based on chitosan membranes containing collagen and keratin

Novel biodegradable and resorbable polymeric membranes that can function as supports for corneal epithelial cells cultures were developed. The materials used to synthesize these supports are natural polymers (i.e., chitosan, collagen and keratin [7 and 17% w/w]). The membranes were crosslinked with a natural crosslinker, genipin. The physicochemical, mechanical, and biological properties of the membranes were determined. It was found that the addition of keratin results in the appearance of antibacterial properties against Escherichia coli and in increased elasticity of the membranes

Evolution or revolution in therapy of acquired corneal limbal stem insufficiency: Holoclar® – a new medicine containing corneal epithelium stem cells

Leczenie niewydolności rąbka rogówki wkroczyło w nowy etap. W terapii zastosowano komórki pochodzące z hodowli. Tkanka uzyskana w laboratorium zawiera komórki macierzyste nabłonka rogówki pozyskane ze strefy rąbkowej. Dzięki temu zastąpienie hodowanym nabłonkiem patologicznych tkanek zapewnia jego stałą odnowę, tak jak dzieje się to w warunkach fizjologicznych. Do inicjacji hodowli wystarczy zaledwie 2 mm2 rąbka rogówki; pobrane komórki wytwarzają prawidłowy wielowarstwowy nabłonek, który zawiera też pulę komórek macierzystych. Odległe obserwacje potwierdzają, że z zastosowaniem tej metody można trwale odtwarzać powierzchnię nabłonkową rogówki.Treatment of corneal limbal insufficiency has entered a new stage. The cells from the culture were used in the therapy. The tissue produced in the laboratory contains stem cells of the corneal epithelium obtained from the limbal zone. With this technology, replacing the pathological tissue with the cultured epithelium gives its constant renewal, as it happens under physiological conditions. Only 2 mm2 of the corneal limbus is needed to initiate the culture, the harvested cells produce a normal multilamellar, stratified epithelium, that also contains a population of stem cells. Long-term observations confirm that this method can permanently maintain the epithelial surface of the cornea

Synthesis of Nonsymmetrically Substituted 2,3-Dialkoxyphenazine Derivatives and Preliminary Examination of Their Cytotoxicity

Fourteen new 2,3-dialkoxyphenazine derivatives with two different alkoxy groups bearing R1 and R2 alkyl chains, defined as −CH2CH(CH3)2 and −(CH2)n−1CH3 for n = 1, 2, 4, 6, 8, and 10, were prepared via regioselective synthesis. The applied synthetic protocol is based on the following reactions: the Buchwald–Hartwig coupling of a nonsymmetrically substituted 4,5-dialkoxy-2-nitroaniline with a 1-bromo-2-nitrobenzene derivative featuring additional tert-butyl, trifluoromethyl or two methoxy groups; the reduction of bis(2-nitrophenyl)amine; and a final step of tandem-like oxidation that leads to the preparation of a heterocyclic phenazine system. The regioselectivity of these steps and the molecular structure of the compounds under investigation were confirmed by nuclear magnetic resonance and additionally by single-crystal X-ray diffraction performed for some examples of 5 and 6 phenazine series. For 7-(tert-butyl)-3-isobutoxy-2-(octyloxy)phenazine (5f), 3-(hexyloxy)-2-isobutoxy-7-(trifluoromethyl)phenazine (6e), and 2,3-bis(hexyloxy)-7,8-dimethoxyphenazine (7), viability and cytotoxicity assays were performed on the LoVo human colon adenocarcinoma cell line, with 5f confirmed to exhibit cytotoxicity