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EN
This short review addresses the synthesis of thermoresponsive polymer surfaces and their application for cell tissue engineering. Four classes of synthetic thermoresponsive polymers are discussed: poly(N-isopropylacrylamide)s, poly[oligo(ethylene glycol)methacrylate]s, polyoxazolines and polyethers, most notably, polyglycidol. Synthetic routes leading to thermoresponsive layers on solid support are described. Relationships between structures of the layers and their interactions with cells are analyzed. Chemical (copolymerization or the inclusion of biologically active species) and physical (patterning or themorphology of the surfaces) modifications of macromolecular surfaces are described and their relations to the growth and detachment of cell sheets are reviewed. The application of cell sheets grown and detached from thermoresponsive surfaces to treat diseases is also presented.
PL
Praca stanowi przegląd literatury dotyczącej syntezy termoczułych powierzchni polimerowych i ichzastosowania w inżynierii tkankowej. Omówionocztery klasy termoczułych polimerów: poli(N-izopropyloakryloamidy),poli(metakrylany glikoli oligoetylenowych), polioksazoliny i polietery, w tymprzede wszystkim poliglicydol. Opisano syntetyczne szlaki prowadzące do termoczułych warstw stabilnie i kowalencyjnie związanych ze stałym podłożem. Przeanalizowano zależności między strukturą warstw a ich oddziaływaniem z komórkami. Omówiono chemiczne(kopolimeryzacja, dołączenie do polimerubiologicznie aktywnego związku) i fizyczne (modelowanie, morfologia powierzchni) modyfikacje powierzchni polimerowych oraz ich związek ze wzrostem i odczepianiem komórek. Przedstawiono również zastosowanie wyhodowanychi odczepionych od termoczułych powierzchni komórek w postaci arkusza wleczeniu różnych chorób.
EN
Covalent attachment of a thermoresponsive polymer to solid support leads to layers exhibiting temperature-dependent properties. Below the cloud point temperature (TCP) of the thermoresponsive polymer the layer is hydrophilic – it is hydrated and polymer chains adopt an expanded conformation. Above TCP, the polymer chains collapse due to dehydration and the surface becomes hydrophobic. This is a reversible process, lowering the temperature cause hydration and swelling of the layer. Such thermoresponsive layers can be obtained via reactions of entities present on the surface (e.g. functional groups, radicals etc.) with complementary functionalities in the polymer chains (grafting to) or with monomer subjected to polymerization (grafting from). Thermoresponsive layers may be used in many biomedical applications such as separation of molecules or cell sheet engineering. In this work, well-defined thermoresponsive (co)polymers of glycidol and ethyl glycidyl carbamate (mPGl), 2-ethyl and 2-nonyl-2-oxazoline (PENOx) as well as homopolymers of 2-isopropyl-2-oxazoline (PIPOx) were grafted to functionalized glass and silica substrates with the aim to obtain thermoresponsive layers for potential application in cell sheet engineering. Presence of polymers covalently bonded to substrates was confirmed by FT-IR and XPS studies. The polymer layers were 5-50 nm thick, depending on the molar mass and polymer concentration. Microscopic techniques indicated a smooth surface of mPGl layers, slightly rough texture of PENOx layers and fibrille-like fibers surface of PIPOx layers. Ellipsometry and contact angle studies revealed the response of layers to temperature changes. Biocompatibility of layers with dermal fibroblasts was confirmed by toxicity tests. Thermoresponsive surfaces were employed as substrates for skin cell culture and harvesting. Fibroblasts adhesion and proliferation on investigated surfaces was comparable with control sample. A confluent cell sheet was formed after 24 hours of culture. The influence of surface properties on cell adhesion and proliferation was examined. Detachment of cells from surfaces was controlled by variation of the temperature. An intact monolayer of cultured dermal fibroblasts was detached. No mechanical or enzymatic methods were required to harvest the cell sheets. Skin cell sheets, detached from thermoresponsive polymer layers may be applied in the cell sheet engineering that is highly desirable in tissue regeneration.
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