Effect of protein and cell behavior on pattern-grafted thermoresponsive polymer

Abstract

A thermoresponsive copolymer, poly(Nisopropylacrylamide-co-acrylic acid), was coupled with azidoaniline. The azidophenyl-derivatized copolymer was grafted in a specific pattern on a polystyrene matrix by photolithography. The surface micropattern appeared and disappeared interchangeably, as observed under a phase-contrast microscope, by varying the temperature between 10 degrees C and 37 degrees C. The copolymer-grafted polystyrene surface was hydrophobic at 37 degrees C and hydrophilic at 10 degrees C. Albumin and fibronectin adsorption on the matrix was investigated using the fluorescent-labeling method. Fibronectin adsorbed onto both the grafted and nongrafted regions, while albumin adsorbed more onto the nongrafted regions than the grafted regions. Protein adsorption did not affect surface wettability. Mouse fibroblast STO cells were cultured on tissue culture plates pattern-grafted with the thermoresponsive copolymer. Fibronectin adsorption enhanced cell spreading, while albumin reduced it. When the temperature was lowered, the cells selectively detached from the surface areas grafted with the thermoresponsive copolymer when cultured in serum-free medium; the cells partially detached from these areas when cultured in serum-containing medium. The effect of serum proteins on cell detachment was similar to that caused by a mixture of albumin and fibronectin. Albumin adsorption did not affect the detachment of cells, while fibronectin adsorption inhibited it. The results of the present study indicate that a pattern-grafted, thermoresponsive, azidophenyl-derivatized copolymer can effectively facilitate selective cell detachment under some conditions such as serum-free culture or preadsorption of albumin. The pattern-grafting technique will be useful for qualitative microscopic comparison of surfaces prepared differently on one chip under the same conditions.

Biology on a Chip: Microfabrication for Studying the Behavior of Cultured Cells

“…Mouse fibroblasts grown on the copolymer-grafted surface area were selectively detached by lowering the temperature in serum-free medium, but only partially detached in serum-containing medium. 60,61 Growth factors such as insulin could also be immobilized to the thermoresponsive polymer and showed stimulation of cell growth. 62,63 Mrksich et al 47 developed an electrochemical switch to reverse the cell adhesiveness of a substrate (or select regions of a substrate).…”

Microimmunoassay Using a Protein Chip: Optimizing Conditions for Protein Immobilization

“…It is also necessary to immobilize the protein antigens on a glass slide in a way that preserves their immunological characteristics exposing linear or conformational epitopes. Several methods of protein immobilization on glass slides have been described previously (1,2,3,4,5,6,7,9,10). Although extensive studies with protein microarrays have been performed (11,12,13,14,15), fundamental analyses comparing the conventional methods easily accessible to a laboratory have not been studied.…”

Effect of Tetrafluoromethane Plasma Treatment of PMMA on MCF-7 Cell Proliferation

“…To tether the bioactive compounds to PMMA, surface modification methods, such as wet chemical method, ionized gas treatment, and UV radiation need to be conducted. Surface properties such as electrical charge, functional groups [5], and contact angle [6][7] play important roles on governing the response of biomolecules to the surface [6,[8][9][10].…”