Cell Spheroid Formation on the Surface of Multi-Block Copolymers Composed of poly(2-methoxyethyl acrylate) and Polyethylene Glycol.

Three-dimensional (3D) structured cells have great drug screening potential because they mimic in vivo tissues better than two-dimensional cultured cells. In this study, multi-block copolymers composed of poly(2-methoxyethyl acrylate) (PMEA) and polyethylene glycol (PEG) are developed as a new kind of biocompatible polymers. PEG imparts non-cell adhesion while PMEA acts as an anchoring segment to prepare the polymer coating surface. The multi-block copolymers show higher stability in water than PMEA. A specific micro-sized swelling structure composed of a PEG chain is observed in the multi-block copolymer film in water. A single NIH3T3-3-4 spheroid was formed in 3 h on the surface of the multi-block copolymers with 8.4 wt% PEG. However, at a PEG content of 0.7 wt%, spheroid formed after 4 days. The adenosine triphosphate (ATP) activity of cells and the internal necrotic state of the spheroid change depending on PEG loading in the multi-block copolymers. As the formation rate of cell spheroid on low-PEG-ratio multi-block copolymers is slow, internal necrosis of cell spheroid is less likely to occur. Consequently, we successfully control the cell spheroid formation rate by changing the PEG chain content in multi-block copolymers. These unique surfaces are suggested to be useful for 3D cell culture. This article is protected by copyright. All rights reserved.