Fermentation based carbon nanotube multifunctional bionic composites

Abstract

The exploitation of the processes used by microorganisms to digest nutrients for their growth can be a viable method for the formation of a wide range of so called biogenic materials that have unique properties that are not produced by abiotic processes. Here we produced living hybrid materials by giving to unicellular organisms the nutrient to grow. Based on bread fermentation, a bionic composite made of carbon nanotubes (CNTs) and a single-cell fungi, the Saccharomyces cerevisiae yeast extract, was prepared by fermentation of such microorganisms at room temperature. Scanning electron microscopy analysis suggests that the CNTs were internalized by the cell after fermentation bridging the cells. Tensile tests on dried composite films have been rationalized in terms of a CNT cell bridging mechanism where the strongly enhanced strength of the composite is governed by the adhesion energy between the bridging carbon nanotubes and the matrix. The addition of CNTs also significantly improved the electrical conductivity along with a higher photoconductive activity. The proposed process could lead to the development of more complex and interactive structures programmed to self-assemble into specific patterns, such as those on strain or light sensors that could sense damage or convert light stimulus in an electrical signal.

Graphene and Carbon Nanotube Auxetic Rubber Bionic Composites with Negative Variation of the Electrical Resistance and Comparison with Their Nonbionic Counterparts

“…Figure c–f shows the images of the bionic SR composites. Considering that the strategy adopted in this work is to reproduce the Saccharomyces cerevisiae through a process called “budding”, where a daughter cell is initiated as growth from the mother cell, it is reasonable to suggest that the yeast cells remain trapped in the gelling matrix . As seen in Figure c, the yeast cells were completely removed by post‐thermal annealing at 250 °C of the bionic composite after their cure.…”

“…As an example bacteria and fungi were extensively used in materials science as simple templates with monodisperse sizes and controlled shapes as well as scalable growth . More recently the metabolic activities of biological processes such as beer fermentation, were adopted to generate porous hierarchical composites in gelling materials during their cross‐linking or bionic porous nanocomposites based on intractable polymers …”

Engineered Living Materials: Prospects and Challenges for Using Biological Systems to Direct the Assembly of Smart Materials

“…Nevertheless, they served as a precursor to the development of materials wherein the living cells played a more direct role in the performance of the final composite materials. Follow‐on work form the same group described bionic composites of yeast and carbon materials that were produced using fermentation ( Figure a) . First, fermentation was used to produce yeast–carbon nanotubes (CNT) bionic composites with improved mechanical, electrical and optical properties compared with yeast and CNTs simply blended together .…”

“…Bottom: Reproduced with permission. [] Copyright 2016, Nature Publishing Group. b) Biomemory device fabricated through the self‐assembly of Shewanella oneidensis bacteria with graphene oxide (left: SEM image of the composite, right: Write/erase function of the biomemory device).…”

Combining Living Microorganisms with Regenerated Silk Provides Nanofibril-Based Thin Films with Heat-Responsive Wrinkled States for Smart Food Packaging

“…Inspired by our previous work where the metabolic activity of living microorganisms was used as an engineered platform for the fabrication of advanced carbon-based materials [19], here we extend this approach, with emphasis on the fermentation process used for centuries in wine-and bread-making, to produce bionic composites which integrate regenerated silk nanofibrils that from the geometrical point of view and in terms of mechanical properties are similar to carbon nanotubes. The resulting reduced volume fraction of nanofibrils within the film could make the fermented hybrid composite more resistant to fracture with self-repairing properties exploiting the microorganisms' growth process that allows for the intracellular transport of nanomaterials, and the CO2 bubbles produced during fermentation could be used to produce porous architectures for biomedical applications.…”