title: Poly(N-isopropylacrylamide) hydrogels with interpenetrating multiwalled carbon nanotubes for cell sheet engineering.
abstract: Hydrogels have been developed as artificial extracellular matrixes (ECMs) to mimic native tissue microenvironments for various applications. Unfortunately, poly(N-isopropylacrylamide) (PNIPAAM)-based hydrogels are not suitable for cell culturing and cell sheet preparation. Carbon nanotubes (CNTs), with their mechanical strength and electrical conductivity, have been considered as additives to increase the applicability of hydrogels to cell encapsulation and advance cardiac electrophysiological functions. A simple method for fabrication of PNIPAAM hydrogels interpenetrated with multiwalled CNTs (MWCNTs) as substrates for cell sheet preparation is reported. The results demonstrate that PNIPAAM hydrogels with interpenetrating MWCNTs still exhibit thermosensitive behavior. It is also found that epithelial Madin-Darby canine kidney (MDCK) cells can only attach and proliferate on MWCNT-interpenetrated PNIPAAM hydrogels. Furthermore, the PNIPAAM hydrogels with MWCNTs possess higher elastic moduli and hydrophobicities than those without MWCNTs, suggesting these two characteristics are necessary for the cells to attach to the hydrogel surfaces. Moreover, cell sheets can only be harvested from PNIPAAM hydrogels with MWCNTs because of their high ratio of cell attachment. Thus, this simple method provides sufficient mechanical strength to PNIPAAM hydrogels so that anchorage-dependent cells can be cultivated and provides a superior system for preparing cell sheets.
authors.affiliation: Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC.
authors.forename: Yu-Shuan
authors.initials: YS
authors.lastname: Chen
authors.forename: Pei-Chun
authors.initials: PC
authors.lastname: Tsou
authors.forename: Jem-Mau
authors.initials: JM
authors.lastname: Lo
authors.forename: Hsieh-Chih
authors.initials: HC
authors.lastname: Tsai
authors.forename: Yan-Zhen
authors.initials: YZ
authors.lastname: Wang
authors.forename: Ging-Ho
authors.initials: GH
authors.lastname: Hsiue
mesh_terms: D000180:Acrylic Resins / Q000494:pharmacology*; D000818:Animals; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods*; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D004285:Dogs; D055119:Elastic Modulus / Q000187:drug effects; D020100:Hydrogels / Q000138:chemical synthesis / Q000494:pharmacology*; D061985:Madin Darby Canine Kidney Cells; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D012212:Rheology / Q000187:drug effects; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties / Q000187:drug effects; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D000180:Acrylic Resins; D020100:Hydrogels; D037742:Nanotubes, Carbon; C052970:poly-N-isopropylacrylamide
keywords: Anchorage-dependent cells; Cell sheet; Hydrogels; Mechanical strength and hydrophobicities; Multi-walled carbon nanotubes; Poly(N-isopropylacrylamide)