title: Chondrocyte spheroids on microfabricated PEG hydrogel surface and their noninvasive functional monitoring.
abstract: A two-dimensional microarray of 10 000 (100 × 100) chondrocyte spheroids was constructed with a 100μm spacing on a micropatterned gold electrode that was coated with poly(ethylene glycol) (PEG) hydrogels. The PEGylated surface as a cytophobic region was regulated by controlling the gel structure through photolithography. In this way, a PEG hydrogel was modulated enough to inhibit outgrowth of chondrocytes from a cell adhering region in the horizontal direction, which is critical for inducing formation of three-dimensional chondrocyte aggregations (spheroids) within 24 h. We further report noninvasive monitoring of the cellular functional change at the cell membrane using a chondrocyte-based field effect transistor. This measurement is based on detection of extracellular potential change induced as a result of the interaction between extracellular matrix protein secreted from spheroid and substrate at the cell membrane. The interface potential change at the cell membrane/gate interface can be monitored during the differentiation of spheroids without any labeling materials. Our measurements of the time evolution of the interface potential provide important information for understanding the uptake kinetics for cellular differentiation.
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Otsuka
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Nagamura
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.
authors.forename: Akie
authors.initials: A
authors.lastname: Kaneko
authors.affiliation: Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kutsuzawa
authors.affiliation: Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Sakata
authors.affiliation: Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miyahara
keywords: 3D cell culture; bovine articular cartilage; field effect transistor (FET); glycosaminoglycan (GAG); spheroid