Merging Electric Bacteria with Paper

Abstract

other electronic components. [18,19] Revolutionary combinations of synthetic materials and paper allow the development of unconventional electronics, which cannot be built with traditional semiconductor technology. While the combinations are revolutionary, these materials can be blended with paper by using mature manufacturing processes, such as roll-to-roll printing, soaking, coating, screen-printing, and dipping. [8,12,[20][21][22] Many functional inks, [23] synthetic polymers, [24] metals, [25] semiconductors, [26] insulators, [27] and nanoparticles [28] have integrated into the paper. The combinations can make paper conductive, biocompatible, biodegradable, smooth, and protective by filling the pores, covering the fibers, and laminating the surface. [6,29,30] Other biological materials such as enzymes, proteins, and DNAs, have also been used to functionalize the paper. [31][32][33] Recently, electric bacteria (exoelectrogens) that are capable of harvesting electrons have been innovatively merged with paper to power on-chip paper devices (Figure 1). [34][35][36] These electric bacteria use respiration to convert biochemical energy stored in organic matter into biological energy, adenosine triphosphate (ATP), where this process involves a cascade of reactions through a system of electron-carrier biomolecules in which electrons are transferred to the terminal electron acceptor, an anode. [37] During the bacterial respiration, protons are also generated, which diffuse through a selective ion exchange membrane and reach a cathode. Those electrons and protons are reduced to water in the presence of catholyte (e.g., oxygen) at the cathode. Paper-based batteries or energy storage devices have been considered as an indispensable component in creating selfsustainable and independent papertronics. [38][39][40] Paper-based solar cells, [41] supercapacitors, [28] nanogenerators, [42] thermoelectrics, [21] and chemical fuel cells [43] have been widely studied as potential energy sources in various applications. Incorporating electric bacteria into paper can offer a simple but powerful energy source for papertronics especially in remote and resource-limited settings as the bacteria can inhabit any environment even those with extreme conditions. [44] Furthermore, the device can be compact, affordable, and easily integrated into a simple structure's design in a cost-effective and eco-friendly manner. The paper's high roughness and porosity can be advantageous for bacterial accommodation and mass transfer relative to the bacterial energy harvesting while its hydrophilicity easily absorbs bacterial media and holds it for Paper-based electronics (papertronics) are recently considered as one of the most exciting device platforms because of their flexibility, sustainability, ecofriendliness, and low cost as well as their excellent mechanical, dielectrical, and fluidic properties. Now, innovative structure engineering techniques can manipulate diameters of the cellulose fibers of paper, smoothing the roughness and controlling the t...

Paper Robotics: Self‐Folding, Gripping, and Locomotion

“…Fabrication of Folding Structures: The hydrophilic channels were defined with hydrophobic wax boundaries on paper by double-sided printing and letting the wax penetrate asymmetrically. [54,55] Specific wax and channel patterns were designed using a computer aided design tool (AutoCAD software), and the wax was printed onto 8.5″ × 11″ copy paper from Staples using a Phaser printer (ColorQube 8570 from Xerox). Printing various prescribed planar designs of patterns enabled the mass production of different geometries on a single paper sheet, which maintained its inherent flexibility.…”

A Portable, Single-Use, Paper-Based Microbial Fuel Cell Sensor for Rapid, On-Site Water Quality Monitoring

“…Both the current and power On the anode reservoir, a conductive ink consisting of 1wt% poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) (Clevios PH1000, Heraeus, Vandalia, OH, USA) and 5wt% dimethyl sulfoxide (DMSO, Sigma-Aldrich) was injected and air-dried. Then, 2wt% 3-glycidoxypropy-trimethoxysilane (3-GLYMO) was pipetted to improve the hydrophilicity [13] (Figure 2a). For the cathode, a silver-based mixture was prepared by adding 100 mg of Ag 2 O to 2 mL of the conductive ink.…”

“…For the cathode, a silver-based mixture was prepared by adding 100 mg of Ag 2 O to 2 mL of the conductive ink. Our previous works have demonstrated that, compared to the widely used potassium ferricyanide and air-cathode used in the preparation of cathodes in MFCs, Ag 2 O showed greater power performance and provided more versatile device design [13,18]. The mixture was sonicated and vortexed before pipetting it onto the cathode reservoir ( Figure 2b).…”

“…Then carbon ink was screen-printed on top of the anode and cathode reservoirs and was left to be air-dried overnight. Afterwards, the two layers were combined by spraying adhesives on the peripheries of the reservoirs [13] (Figure 2c).…”

“…Paper-based electronics, or "papertronics", have recently attracted a lot of attention, as electronic and fluidic components can be printed onto a paper substrate [12]. Papers offer unique characteristics as electronic components of a device in that they are available in abundance, as well as being cost-effective, flexible, biodegradable, and disposable [13]. Previously, papers have been used in the fabrication of MFCs to provide power for small, portable transceivers and point-of-care diagnostic devices in remote areas [14][15][16].…”