MEMS Graduate Student Seminar: "A pressure sensor assembled by pattern-forming bacteria"
Friday, March 4, 2016
12:00 pm - 1:00 pm
Hudson Hall 141
Will Cao, Duke BME
Abstract: Standard methods for materials fabrication have well-recognized limitations, including the requirement for harsh reaction conditions, negative impact on the environment and manipulators' health, and low energy efficiency. Yet, structured materials consisting of organic and inorganic components naturally emerge in diverse biological systems, such as bone, teeth, and mollusk shells. Drawing inspiration form nature, we use engineered pattern forming bacteria (Payne et al., 2013) as the scaffold to assemble inorganic nanoparticles into self-organized 3D structures. In particular, we engineered E. coli to program spatially patterned expression of a curli amyloid fibril (Chen et al., 2014). By integrating inkjet printing, a porous membrane as the growth platform, and immunolabeling, we generated a programmable organic-inorganic shell structure. This structure was highly programmable by manipulating printing configuration, membrane properties, and the extent of circuit activation. Remarkably, we found that the bacterially fabricated shell structure could function as a pressure sensor that responded to touch. Different geometric parameters of the shell patterns resulted in different sensitivities to the pressure input. Moreover, the shape itself dictates pressure response: a shell structure responds to pressure level whereas a spherical cap structure remains constant. Using this design principle, we constructed a "touch pad" to implement locational pressure sensing....