Light-induced release systems can be triggered remotely and are of interest for many controlled release applications due to the possibility for spatio-temporal release control. In this study a biotin-functionalized photocleavable macromer is incorporated with an o-nitrobenzyl moiety into gelatin methacryloyl(-acetyl) hydrogels via radical cross-linking. Stronger immobilization of streptavidin-coupled horseradish peroxidase occurs in linker-functionalized hydrogels compared to pure gelatin methacryloyl(-acetyl) hydrogels, and a controlled release of the streptavidin conjugate upon UV-irradiation is possible. Liquid chromatography coupled to mass spectrometry (LC-MS) analysis of aqueous linker solutions allows the identification of the main cleavage products and the cleavage kinetics. Thus, it is shown that a significant hydrolysis of the linker occurs at 37 °C. Nevertheless the system reported here is a promising controlled release scaffold for proteins and application in tissue engineering, if background releases of the immobilized drug are tolerable.
Keywords: LC-MS; gelatin methacryloyl; photocleavable linker; stimuli-responsive release; streptavidin-coupled HRP.
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