Construction of biofilms with defined internal architecture using dielectrophoresis and flocculation

Abstract

A novel approach was developed for the construction of biofilms with defined internal architecture using AC electrokinetics and flocculation. Artificial structured microbial consortia (ASMC) consisting of localized layered microcolonies of different cell types were formed by sequentially attracting different cell types to high field regions near microelectrodes using dielectrophoresis. Stabilization of the microbial consortia on the electrode surface was achieved by crosslinking the cells using the flocculant polyethyleneimine (PEI). Consortia of Escherichia coli, Micrococcus luteus, and Saccharomyces cerevisiae were made as model systems. Also, more natural consortia were made of the bacteria Pseudomonas putida, Clavibacter michiganense, and Methylobacterium mesophilum, which are found together in consortia during biodegradation of metal-cutting waste fluids.

Tissue engineering with electric fields: Immobilization of mammalian cells in multilayer aggregates using dielectrophoresis

“…One of the applications of dielectrophoresis that is currently being explored is its use in the formation of tissues or tissue-like materials from suspensions of cells (Markx and Buckle, 2005). Whilst early work has concentrated on the formation of aggregates of microbial cells (Pohl, 1972; see also Alp et al, 2002;Mason et al, 2005;Verduzco-Luque et al, 2003), more recent is its use in mammalian tissue engineering (Albrecht et al, 2005(Albrecht et al, , 2006Alp et al, 2003;Heida et al, 2001a,b;Ho et al, 2006;Matsue et al, 1997;Sebastian et al, 2006). The dielectrophoretic force is used to guide cells to specific high (positive DEP) or low electric field regions (negative DEP) between (micro)electrodes, either as single cells (Gray et al, 2004;Heida et al, 2001a,b;Yu et al, 2004) or as aggregates (Sebastian et al, 2006;Venkatesh and Markx, 2007).…”

Construction by dielectrophoresis of microbial aggregates for the study of bacterial cell dormancy

“…200 l 0.0025% W/V polyethylenimine ͑PEI͒ solution was then pumped into the chambers at a flow rate of 10 l min −1 to immobilize the cells. 24 The PEI solution was kept in the chambers for 30 min and then the PEI was rinsed away with a gentle flow of 0.5M sorbitol. The electric field was removed when all of the cells were fully immobilized.…”

The use of electric fields in tissue engineering

“…23 Although it took a long time before this work was taken up again, in recent years research in this area has gained momentum, with work being done on the construction of tissue-like materials from a variety of cell types. [25][26][27][28][29] Dielectrophoretic spectra of very different cell types are very similar, 30 and the method can be employed with essentially any cell type-microbial, animal or plant-or in fact non-cellular material. [31][32][33] Both negative and positive dielectrophoresis can be used, 32,33 single cell manipulation is possible, [34][35][36][37][38] and aggregate sizes can range from single cells to hundreds of microns.…”

“…Other approaches include the use of crosslinking agents. 29,53,54 Stronger forces can be exerted on the cells with positive dielectrophoresis than with negative dielectrophoresis. However, manipulation of cells with positive DEP necessarily involves the use of low-conductivity iso-osmotic buffers which may negatively influence cell viability.…”