Bacterial cellulose spheroids as building blocks for 3D and patterned living materials and for regeneration

Tom Ellis,Koon-Yang Lee,Joaquin Caro-Astorga,Natalia Herrera,Kenneth T Walker

doi:10.1038/s41467-021-25350-8

Tom Ellis, Koon-Yang Lee + Show 3 more

Open Access

https://doi.org/10.1038/s41467-021-25350-8

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Journal: Nature Communications	Publication Date: Aug 19, 2021
Citations: 59	License type: open-access

Affiliation: Imperial College London

Abstract

Engineered living materials (ELMs) based on bacterial cellulose (BC) offer a promising avenue for cheap-to-produce materials that can be programmed with genetically encoded functionalities. Here we explore how ELMs can be fabricated in a modular fashion from millimetre-scale biofilm spheroids grown from shaking cultures of Komagataeibacter rhaeticus. Here we define a reproducible protocol to produce BC spheroids with the high yield bacterial cellulose producer K. rhaeticus and demonstrate for the first time their potential for their use as building blocks to grow ELMs in 3D shapes. Using genetically engineered K. rhaeticus, we produce functionalized BC spheroids and use these to make and grow patterned BC-based ELMs that signal within a material and can sense and report on chemical inputs. We also investigate the use of BC spheroids as a method to regenerate damaged BC materials and as a way to fuse together smaller material sections of cellulose and synthetic materials into a larger piece. This work improves our understanding of BC spheroid formation and showcases their great potential for fabricating, patterning and repairing ELMs based on the promising biomaterial of bacterial cellulose.

Highlights

Engineered living materials (ELMs) based on bacterial cellulose (BC) offer a promising avenue for cheap-to-produce materials that can be programmed with genetically encoded functionalities
It has been hypothesised that spheroid formation is produced by the adhesion of bacteria to air bubbles produced in shaking media, with cellulose grown at the bubble air–liquid interphase to form a spheroid shape[25]
We visually assessed the cultures for the presence of BC spheroids and used this information to determine the key factors involved in spheroid formation and which combination of growth variables leads to reproducible growth of BC spheroids

Summary

Introduction

Engineered living materials (ELMs) based on bacterial cellulose (BC) offer a promising avenue for cheap-to-produce materials that can be programmed with genetically encoded functionalities. By providing nutrients, water and oxygen, the bacteria can keep growing and seal gaps and tears when they arise, so long as the material has not been dehydrated or sterilised after growth For patterned functionalities, this can theoretically be achieved with BCbased materials by growing these from genetically engineered cells[5]. This can theoretically be achieved with BCbased materials by growing these from genetically engineered cells[5] Another possibility to tackle this problem could be to use modular ELM building blocks and pattern these physically as a mosaic to make larger materials. We define a reproducible method to produce BC spheroids from the bacterium Komagataeibacter rhaeticus We use these BC spheroids as building blocks to build 3D shapes and to create patterned ELMs made of spheroids containing genetically functionalised bacteria that impart fluorescence and send and receive signals. We further demonstrate that spheroid building blocks can be used to regenerate damaged BC materials as fresh, stored or purified spheroids and that this can be used to fuse and assemble independent BC pieces in a mosaic fashion

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