Light-Patterned Current Generation in a Droplet Bilayer Array

Vanessa Restrepo Schild,Sam N Olof,Hagan Bayley,Stuart J Box,Kozhinjampara R Mahendran,Michael J Booth

doi:10.1038/srep46585

Abstract

We have created a 4 × 4 droplet bilayer array comprising light-activatable aqueous droplet bio-pixels. Aqueous droplets containing bacteriorhodopsin (bR), a light-driven proton pump, were arranged on a common hydrogel surface in lipid-containing oil. A separate lipid bilayer formed at the interface between each droplet and the hydrogel; each bilayer then incorporated bR. Electrodes in each droplet simultaneously measured the light-driven proton-pumping activities of each bio-pixel. The 4 × 4 array derived by this bottom-up synthetic biology approach can detect grey-scale images and patterns of light moving across the device, which are transduced as electrical current generated in each bio-pixel. We propose that synthetic biological light-activatable arrays, produced with soft materials, might be interfaced with living tissues to stimulate neuronal pathways.

Highlights

We have created a 4 × 4 droplet bilayer array comprising light-activatable aqueous droplet bio-pixels
Biological light-sensors range from the high-resolution light-sensing electrical arrays in the retina of the eye[1] to the simple eye-spot apparatus found in green algae[2]
It is of interest to develop soft material arrays that generate patterned current signals by a bottom-up synthetic biological approach

Summary

Introduction

We have created a 4 × 4 droplet bilayer array comprising light-activatable aqueous droplet bio-pixels. Aqueous droplets containing bacteriorhodopsin (bR), a light-driven proton pump, were arranged on a common hydrogel surface in lipid-containing oil. The retina comprises an array of photoreceptor cells[3], containing stacks of membrane proteins, the rhodopsins[4] These biological arrays convert light into an electrical signal[1]. We present a 4 × 4 array of bio-pixels, comprising bR-containing droplets arranged on a single common hydrogel structure. The hydrogel acts both as a scaffold for the array and as a medium for ion transport. In our approach, the structure of the array is a soft material containing droplets interfaced through bilayers to a hydrogel, which allow us to detect patterns of light through current generation. Our droplet array can be regarded as a single device in which a light sensor and a current generator are integrated

Methods

Results

Conclusion