We present initial results on using electric field gradients, in a technique called dielectrophoresis (DEP), for the spatiotemporal manipulation of the bacterium K. xylinus; and the impact of the electric field on the synthesis of bacterial cellulose (BC). These are crucial steps for the use of K. xylinus as a robotic printer of architected nanocellulose scaffolds that can be used as is or serve as a precursor to multiple carbonaceous materials. DEP is an established technique that uses electric field gradients for the label-free spatiotemporal manipulation of cells. The strength and direction of the DEP force acting on K. xylinus depends on the frequency of the applied electric field and the dielectric properties of the cell and its suspending media. K. xylinus can synthesize BC, an advantageous source of cellulose over plant cellulose in terms of strength and purity. Particularly, the extraction of biomass from plants and purification of cellulose to remove hemicellulose and lignin is not required in BC production. The use of a bioreactor to produce BC also eliminates the need for forestry operations to produce cellulose. While the fabrication throughput of BC may appear low, it must be compared to the growth rate of plants, with the advantage that pure BC can be directly obtained. By combining DEP techniques with K. xylinus, we attempt to architect BC from the bottom-up and create engineered films that can be subsequently shaped using film shaping techniques like folding and origami. However, the spatiotemporal manipulation of individual K. xylinus cells is still challenging and no methodical study of the effect of an electric field on BC synthesis has been reported; that is, a field with the magnitude necessary to enable spatiotemporal manipulation in a microfluidics reactor. We present two major developments towards the use of K. xylinus as a tiny printer: 1) the use of light-induced DEP, or the use of light fields to enable an electric field gradient, to enable basic manipulation of K. xylinus cells; and 2) the use of a microfluidic reactor featuring microelectrodes to study how electrostimulation can potentially manipulate and influence the synthesis of BC. This second study features experiments running over fourteen days with an AC induced electric field at polarization voltages of 1 Vpp, 2 Vpp, and 5 Vpp at a frequency of 750 kHz. Results suggest that long-term BC synthesis is possible under electric fields necessary for K. xylinus manipulation.

Towards architecting bacterial cellulose

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.