In-vivo, in-situ, light-tunable manipulation of cells' biomechanics on a photoactive azobenzene bio-substrate

In-vivo, real-time study of the local and collective cellular biomechanical responses requires the fine and selective control of the cellular environment. Optical manipulation provides a suitable pathway to achieve non-contact, selective, local, temporal and spatial stimuli. The spectacular photomechanical properties of photoactive bio-substrates such as azobenzene-containing thin polymer films are a new promising strategy to achieve optically triggered local mechanical stimulation of cells. Excited cells exhibit spectacular morphological modifications and area shrinkage, which are dependent on the illumination. In this work we demonstrate that the capabilities of photomechanically active azocontaining substrates to optically stimulate cells' mechanical response can be strongly influenced by the adhesion binding agent used to deposit the living cells on the photoactive layer. This provides a further tool for the photomechanical control of the cellular environment and of the cellular response.