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Nowe termowrażliwe powierzchnie polimerowe do hodowli i uwalniania komórek skóry

Oleszko-Torbus N., Utrata-Wesołek A., Wałach W., Dworak A., Trzebicka B.

Wiadomości Chemiczne

2016

[Z] 70, 11-12

803--818

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.

Study of polystyrene surface local mechanical properties by the atomic force microscopy

Zaitseva A. V., Rudoy V. M., Dement'eva O. V., Kartseva M. E.

Materials Science

2002

Vol. 20, No. 3

37-43

Composites with polymer surface layer serving as a matrix for metal nanoparticles stabilization are very promising materials for modern nano- and optoelectronics, nonlinear optics, catalysis, chemical sensors and biosensors. Successful development of such nanocomposites is impossible without intimate knowledge of polymer surface layer properties (structural, mechanical, chemical, electrical, etc.) at a nanolevel. In this study, local mechanical properties (elastic modulus, wearing qualities) of polystyrene surface layer were investigated by means of atomic force microscopy (AFM). Elastic modulus was determined from the analysis of force-distance curves within the framework of Johnson-Kendall-Roberts model. A significant decrease of elastic modulus near the polystyrene surface relative to its bulk value was observed. Strong dependence of the surface layer mechanical properties on the polymer molecular weight was found. The influence of different types of treatment (annealing, UV-irradiation) on the polystyrene surface layer mechanical properties was investigated. Strong correlations between PS surfach layer mechanical properties and its glass transition temperature variations (studied in our previous works) are discussed.