Green light lithography: a general strategy to create active protein and cell micropatterns

Abstract

Micropatterns of functional protein are important in biotechnology and research. Using noninvasive wavelengths, green light lithography allows to photopattern active proteins with high spatiotemporal control. Patterns of light are projected onto a layer-by-layer (LbL) multiprotein film, where the green light cleavable protein CarH is integrated into the first layer. CarH is a tetramer in the dark and dissociates under green light into its monomers. The LbL protein film is designed to have different functional proteins in each layer based on the specific and polyvalent interactions between Ni²⁺-NTA groups and His-tagged proteins, thus providing oriented protein immobilization under mild conditions to preserve protein activity. This enables the remote release of proteins in the upper layers by exposing the film to green light with 1 μm spatial and 10 s temporal resolution. Green light lithography is successfully used to produce complex patterns of different functional proteins including fluorescent proteins as well as the cell adhesion protein fibronectin. These protein patterns are compatible with cell cultures and the photopatterned fibronectins allow spatial control of cell adhesion. Overall green light lithography provides a flexible way to micropattern His-tagged proteins with high spatiotemporal control and in an oriented way by using noninvasive green light assuring protein function.