Modulating surface density of proteins via caged surfaces and controlled light exposure

We demonstrate the possibility of tuning the degree of functionalization of a surface using photoactivatable chemistries and controlled light exposure. A photosensitive organosilane with a protected amine terminal group and a tetraethyleneglycol spacer was synthesized. A o-nitrobenzyl cage was used as the photoremovable group to cage the amine functionality. Surfaces with phototunable amine densities were generated by controlled irradiation of silica substrates modified with the photosensitive anchor. Protein layers with different densities could be obtained by successive coupling and assembly steps. Protein surface concentrations were quantified by reflectance interference. Our results demonstrate that the protein density correlates with the photogenerated ligand density. The density control was proved over four coupling steps (biotin, SAv, BTtris-NTA, MBP, or GFP), indicating that the interactions between underlying layer and soluble targets are highly specific and the immobilized targets at the four levels maintain their full functionality. Protein micropatterns with a gradient of protein density were also obtained. © 2011 American Chemical Society.Fil: Álvarez, Marta. Max-Planck-Institut fur Polymerforschung; AlemaniaFil: Alonso, José María. Max Planck Institut fur Metallforschung; AlemaniaFil: Filevich, Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Bhagawati, Maniraj. Universitat Osnabruck; AlemaniaFil: Etchenique, Roberto Argentino. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Piehler, Jacob. Universitat Osnabruck; AlemaniaFil: del Campo, Aránzazu. Max-Planck-Institut fur Polymerforschung; Alemani