Oxygen plasma-treated thermoresponsive polymer surfaces for cell sheet engineering

• Published in: Biotechnology and bioengineering 2010-06, Vol.106 (2), p.303-310
• Main Authors: Shimizu, Kazunori, Fujita, Hideaki, Nagamori, Eiji
• Format: Article
• Language: English
• Subjects: Acrylamides - chemistry; Acrylic Resins; Animals; Biocompatible Materials - chemistry; Biological and medical sciences; Biotechnology; cell culture; Cell Differentiation; Cell Line; cell sheet; Cells; Fundamental and applied biological sciences. Psychology; Gases - chemistry; Hot Temperature; Materials Testing; Mice; Muscle Fibers, Skeletal - cytology; Muscle Fibers, Skeletal - physiology; Musculoskeletal system; Myoblasts - cytology; Myoblasts - physiology; Oxygen; Oxygen - chemistry; oxygen plasma; Plasma; poly-N-isopropylacrylamide; Polymers; Polymers - chemistry; Proteins; skeletal muscle cell; Surface Properties; Temperature; Tissue engineering; Tissue Engineering - methods
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.22677

Although cell sheet tissue engineering is a potent and promising method for tissue engineering, an increase of mechanical strength of a cell sheet is needed for easy manipulation of it during transplantation or 3D tissue fabrication. Previously, we developed a cell sheet-polymer film complex that had enough mechanical strength that can be manipulated even by tweezers (Fujita et al., 2009. Biotechnol Bioeng 103(2): 370-377). We confirmed the polymer film involving a temperature sensitive polymer and extracellular matrix (ECM) proteins could be removed by lowering temperature after transplantation, and its potential use in regenerative medicine was demonstrated. However, the use of ECM proteins conflicted with high stability in long-term storage and low cost. In the present study, to overcome these drawbacks, we employed the oxygen plasma treatment instead of using the ECM proteins. A cast and dried film of thermoresponsive poly-N-isopropylacrylamide (PNIPAAm) was fabricated and treated with high-intensity oxygen plasma. The cells became possible to adhere to the oxygen plasma-treated PNIPAAm surface, whereas could not to the inherent surface of bulk PNIPAAm without treatment. Characterizations of the treated surface revealed the surface had high stability. The surface roughness, wettability, and composition were changed, depending on the plasma intensity. Interestingly, although bulk PNIPAAm layer had thermoresponsiveness and dissolved below lower critical solution temperature (LCST), it was found that the oxygen plasma-treated PNIPAAm surface lost its thermoresponsiveness and remained insoluble in water below LCST as a thin layer. Skeletal muscle C2C12 cells could be cultured on the oxygen plasma-treated PNIPAAm surface, a skeletal muscle cell sheet with the insoluble thin layer could be released in the medium, and thus the possibility of use of the cell sheet for transplantation was demonstrated. Biotechnol. Bioeng. 2010;106: 303-310.