For a decade, individual living cells have been encased within polyelectrolytes and nanomaterials.^1,2  Layer-by-layer (LbL) self-assembly is the deposition or assembly of polyelectrolytes/nanomaterials, applied sequentially to the surfaces of living cells, through electrostatic interactions between oppositely charged polyelectrolytes or nanomaterials. LbL films are useful in integrating living cells with various materials for the following reasons.³  (1) LbL films are formed in a substrate-nonspecific manner, but are only manipulated by the surface charge. (2) Their thickness can be finely controlled on a 1-nm scale by the number of depositions. (3) LbL films are fabricated with extremely simple and low-cost processes, which make them highly accessible. (4) All the processes involved can be performed in biorelevant conditions, such as aqueous media, ambient pressure, and room temperature.