Home / Interviews / Interview with Prof Seokheun (Sean) Choi
Prof Seokheun (Sean) Choi
Prof Seokheun (Sean) Choi
Lead researcher- Dept of Electrical & Computer Engineering

Interview with Prof Seokheun (Sean) Choi

Textiles conducive for flexible, wearable electronic devices

A team of researchers from the State University of New York (SUNY), popularly called the Binghamton University, have developed a flexible and stretchable bio-battery powered by bacteria from fabric. The bio-battery has the potential to reform the future of wearable electronics and smart textiles. Lead researcher Prof Seokheun (Sean) Choi from the university's department of electrical & computer engineering talks to Fibre2Fashion about the need for flexible batteries and explains the potential of textile-based, bacteria-powered bio-battery.

TT: Does the fabric composition impact the working of microbes and the bio-batteries? What kind of fabric works best?

We used a fabric comprising 92 per cent polyester and 8 per cent spandex. We selected this fabric because it was stretchable enough for the mechanical deformation tests and hydrophilic enough for the storage of the bacteria-containing liquid. Conductive textiles are required to extract electrons from the microorganisms, and at the same time, the textiles must have open pores and hydrophilic features to adsorb the cells in liquid while the device needs to be mechanically flexible, stretchable and easily integratable with other necessary electronic components.

 
TT: What sparked the idea to create this textile-based, bacteria-powered battery?

Textile-based wearable electronics have recently emerged as a technology that promises next-generation, ubiquitous health monitoring. However, there has been a significant challenge in creating a truly self-reliant and standalone wearable sensing system that does not rely on an external power source. Traditional battery-operated wearable devices cannot realise long-term advanced functionality because of finite energy budgets available from existing batteries. Furthermore, the batteries are too bulky, rigid and heavy to be integrated in thin, light-weight and flexible fabric-based devices. Even the latest advances in flexible energy storage devices, such as supercapacitor and lithium ion batteries, have not been considered as a sole potential platform for self-sustaining, practical use because of their low energy capacity and frequent recharging requirements. 

Microbial fuel cells (MFCs) used in this work are arguably the most underdeveloped for wearable electronic applications because microbial cytotoxicity may pose health concerns. Reported work on wearable MFCs was either unavailable or quite limited. However, if we consider that humans possess more than 3.8×1013 bacterial cells compared with 3.0×1013 human cells in their bodies, the direct use of bacterial cells as a power resource interdependently with the human body is conceivable for wearable electronics. 


What sparked the idea to create this textile-based, bacteria-powered battery?
TT: You have already tested this on paper. How will it be more relevant on fabric?

Because of its light-weight, low-cost, disposable and flexible features, a paper MFC can be potentially integrated into ubiquitous newspapers, wrapping papers, wallpapers and other objects. However, extremely harsh operating conditions, for example, those that require bending, twisting, folding and stretching, demand development of a fully flexible and stretchable MFC. 

Textiles are attractive materials for flexible devices and offer superior elastomeric properties towards achieving conformal contact with non-planar, unsymmetrical surroundings. Low-cost and scalable fabrication based on well-established traditional textile manufacturing techniques can also be used, and other manufacturing techniques can add other functions. Furthermore, textiles are light-weight, inexpensive and disposable. More specifically, textiles can be ideal supports for substrates and promise functional components for the development of flexible and stretchable MFCs.


You have already tested this on paper. How will it be more relevant on fabric?
TT: What kind of wearable tech-gadgets can be empowered using MFCs?

With the rapid evolution of wireless sensor networks for the emerging Internet-of-Things (IoT), there is a clear and pressing need for flexible and stretchable electronics that can be easily integrated with a wide range of surroundings to collect real-time information. Those electronics must perform reliably even while closely - even intimately when used on humans - attached while deformed toward complex and curvilinear shapes. To achieve the standalone and sustainable operation of the sensor networks, we considered a flexible, stretchable, miniaturised bio-battery as a truly useful energy technology because of their sustainable, renewable and eco-friendly capabilities. For the long-term goal, other wearable electronics, such as activity trackers, socks and gloves, can be powered as well.

TT: What is the cost of developing and using such fabrics-based wearable technology?

It is hard to say at this moment because this work is in the infant stage.

TT: How do MFCs work?

Most microorganisms 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. Most forms of respiration use a soluble compound as an electron acceptor, such as oxygen, nitrate and sulfate; however, some microorganisms are able to respire solid electron acceptors to obtain biological energy. These microorganisms can transfer electrons produced via metabolism across the cell membrane to an external electrode. MFCs typically comprise anodic and cathodic chambers separated by a proton exchange membrane (PEM) so that only H+ or other cations can pass from the anode to the cathode. A conductive load connects the two electrodes to complete the external circuit.

TT: What is the amount of power that can be generated using your innovation?

The device generated a maximum power of 6.4µW/cm2 and current density of 52µA/cm2, which are similar to other flexible paper-based MFCs.

TT: What was the response you received at the 21st International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTas) organised at Savannah, Georgia, in October 2017 for this breakthrough?

This work gained significant attention from the community and was reported by many media outlets, including ScienceDaily, Newswise, Techxplore and EurekAlert.

TT: What are the challenges that your innovation needs to overcome for it to be commercially viable?

First, the power needs to be improved significantly for the future applications. Second, we will demonstrate that sweat generated from the human body can be a potential fuel to support bacterial viability, providing the long-term operation of the MFCs.

TT: How do you plan to take it forward from here? What other possibilities do you see with MFCs within the textile realm?

Compared to traditional batteries and other enzymatic fuel cells, the MFCs can be the most suitable power source for wearable electronics because the whole microbial cells as a biocatalyst provide stable enzymatic reactions and long life time. Sweat generated from the human body can be a potential fuel to support bacterial viability, providing the long-term operation of the MFCs.

TT: Please explain how would sweat be used in this process?

The organic fuel for microorganisms can be any type of biodegradable substrate, including wastewater, soiled water from a puddle, and biological/physiological fluids, such as tears, urine, blood and sweat.

TT: A whole lot of research is being carried out in this field. How do you keep yourself abreast of what the peer community is up to?

Yes. Flexible electronics are getting more and more attention these days because of the wide application possibilities. However, we have tended to overlook the importance of flexible energy supplying devices even though they are necessary for a truly stand-alone device platform. My stretchable and twistable power device printed directly onto a single textile substrate can establish a standardised platform for flexible bio-batteries and will be potentially integrated into wearable electronics in the future.

TT: If we were to ask you to do some crystal gazing, how do you think the fashion apparel scenario is likely to be in terms of smart wearables?

Smart wearables will attract greater attention because of their continuous interaction with the human body, such as monitoring blood pressure, heart rate, motion, biomarkers in sweat, and other health-related conditions. Furthermore, smart wearables will enable a next-generation of smart, stand-alone, always-on wireless sensor networks designed to collect real-time information for human safety and security. (HO)

Published on: 04/01/2018

DISCLAIMER: All views and opinions expressed in this column are solely of the interviewee, and they do not reflect in any way the opinion of technicaltextile.net.


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