In this paper, we present an array of tunable microlenses on polydimethylsiloxane (PDMS) microfluidic chips as a convenient platform for the study of cell responses to mechanical strains. This array of microlenses is an array of microwells covered with a thin PDMS membrane that are connected by microfluidic channels. The deformation of the PDMS membrane on the microlenses is tuned by external hydraulic pressure that is introduced through the microchannels. The degree of deformation of the PDMS membrane can be estimated from the focal length of the microlens, and the corresponding mechanical strain that is caused can be calculated from finite element simulation. We demonstrate the capability of this array of microlenses as a general platform for studying the influence of mechanical strain on adherent cells by using NIH 3T3 fibroblasts and HeLa cells as our models.
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