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Published November 1990 | public
Journal Article

Photoregulation of the binding of an azobenzene-modified poly(methacrylic acid) to phosphatidylcholine bilayer membranes

Abstract

Radical copolymerization of a 4:1 mixture of methacrylic acid and N-[4-(phenylazo)-phenyl]methacrylamide afforded a copolymer of methacrylic acid bearing 10.4 mol% pendent azobenzene units. The copolymer was sensitive to irradiation by virtue of the photochemical trans-to-cis isomerization of the pendent chromophore. The pH-dependent conformational transition characteristic of poly(methacrylic acid) was shifted to a higher pH by the hydrophobic nature of the azobenzene units, but viscosity measurements revealed no further shift in the transition upon photoisomerization. The potentiometric titration curves of the two photoisomeric states of the chain were displaced in a manner consistent with the enhanced polarity of the cis form of the chromophore. The adsorption of the chain on phosphatidylcholine bilayer membranes was strikingly sensitive to light; at pH 7, the cis form adsorbed weakly if at all, whereas the trans form bound strongly to the membrane surface with concomitant reorganization of the lipid bilayer structure.

Additional Information

© 1990 Butterworth-Helnemann Ltd. This work was supported by US Army Research Office grant DAAL03-88-K-0038. We thank Professor Sheila E. Browne of Mount Holyoke College for use of the pulsed N_2 laser.

Additional details

Created:
August 22, 2023
Modified:
October 19, 2023