A Modified Consumer Inkjet for Spatiotemporal Control of Gene Expression

Daniel J Cohen,Michel M Maharbiz,Roberto C Morfino,Christophe Herman

doi:10.1371/journal.pone.0007086

Daniel J Cohen, Michel M Maharbiz + Show 2 more

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https://doi.org/10.1371/journal.pone.0007086

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Abstract

This paper presents a low-cost inkjet dosing system capable of continuous, two-dimensional spatiotemporal regulation of gene expression via delivery of diffusible regulators to a custom-mounted gel culture of E. coli. A consumer-grade, inkjet printer was adapted for chemical printing; E. coli cultures were grown on 750 µm thick agar embedded in micro-wells machined into commercial compact discs. Spatio-temporal regulation of the lac operon was demonstrated via the printing of patterns of lactose and glucose directly into the cultures; X-Gal blue patterns were used for visual feedback. We demonstrate how the bistable nature of the lac operon's feedback, when perturbed by patterning lactose (inducer) and glucose (inhibitor), can lead to coordination of cell expression patterns across a field in ways that mimic motifs seen in developmental biology. Examples of this include sharp boundaries and the generation of traveling waves of mRNA expression. To our knowledge, this is the first demonstration of reaction-diffusion effects in the well-studied lac operon. A finite element reaction-diffusion model of the lac operon is also presented which predicts pattern formation with good fidelity.

Highlights

The development of methods that introduce spatiotemporal perturbations into developing, multi-cellular systems via soluble molecules has a long history [1,2,3,4] and a rich, recent body of literature
This paper presents the adaptation of a commercial, low-cost, piezoelectric inkjet printer and commercial compact discs (CDs) for use as a chemical interface system designed to actively regulate cellular development (Figure 1)
We were surprised by the observation that the bistable nature of the lac operon’s feedback system, when perturbed by patterns of lactose and glucose, can lead to coordination of cell expression patterns across a field in ways that mimic motifs seen in developmental biology

Summary

Introduction

The development of methods that introduce spatiotemporal perturbations into developing, multi-cellular systems via soluble molecules has a long history [1,2,3,4] and a rich, recent body of literature. Advances in microfluidics [5,6,7,8,9,10] and biochemistry [11,12,13,14] are beginning to open the door to direct modulation of developmental pattern formation at the spatial and temporal scale of the cell’s control circuitry. Such devices can provide spatially rich, real-time input-output (I/O) signals to bias toward developing cells into specific phenotypes. In the context of regenerative medicine and tissue engineering, these devices could potentially provide active, spatiotemporal control of morphogenesis [8,17,18]

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