Blue Light Patterning for Engineered Living Materials

Engineered living materials have many exciting properties such as self-healing, bioresponstivity, and the formation of composite materials with complex structures. One challenge in the advancement of engineered living materials is controlling the growth of single cells to form micro- and nano-scale patterns. We, and others, have reported the use of low intensity blue light to control the resting membrane potential of bacteria at the single cell level. We found that blue light (480 nm, &lt;60 s) can slow the growth of <i>B. subtilis</i> and <i>E. coli</i> without damaging the cells. The growth rate of bacteria is inversely proportional to blue light exposure time. We have used this method to pattern bacteria by controlled cell growth. This use of blue light provides a low-cost, high-throughput method for patterning biofilms or the deposition of materials by bacteria, such as bacterial cellulose and calcium carbonate. Current research is aimed at characterizing the underlying mechanism for the slowed bacteria growth including hyperpolarization, generation of reactive oxygen species, and enzyme activity.