Mask-directed multiphoton lithography

We report a strategy to direct the multiphoton photocrosslinking (MPP) of proteins using mask objects or transparency-based masks. This approach enables rapid prototyping and generation of microstructures and functional surface gradients with arbitrary three-dimensional features. We demonstrate use of this strategy to transfer detailed shapes into biomaterial patterns and to fabricate microchambers capable of trapping and incubating a single motile bacterium.