Optical manipulation of biological objects on azobenzene-containing systems

Cells interact with a chemical and mechanical environment that influences their adaptive response and conditions the physiology and pathophysiology of the tissues. Much effort is being made to reconstruct simple systems in order to study the reciprocal influences of tissues and their environment, as well as to measure the consequences of environmental disturbances on cells. Specific tools are required for the in-vivo, real-time manipulation of the cellular environment's mechanical properties and for the measurement of the resulting local and collective cellular biomechanical responses. One innovative solution is the use of photoactive systems such as azobenzene-containing polymer materials (azopolymers), whose microstructure and mechanical optical and surface properties can be modulated in time and space by light. Here we show that azopolymer bio-substrates can be used to optically control and study the cellular response of mouse fibroblasts and to single out different classes of cellular responses that might specifically depend on the photo-induced mechanical modification of the environment surrounding the cellular focal adhesions.