Printed bioelectronic sensors for BIA (Bioimpedance Analysis), ECG (Electrocardiography), and EMG (Electromyography)

Inkjet-printed flexible gold electrode array consisting of 31 electrodes, which is used for impedance mapping of conformal surfaces.

Non-invasively mapping pressure-induced tissue damage with inkjet-printed flexible gold electrode array.

Bioelectronic interfaces require electrodes that are mechanically flexible and chemically inert. Flexibility allows pristine electrode contact to skin and tissue, and chemical inertness prevents electrodes from reacting with biological fluids and living tissues. Since a manufacturing process to fabricate gold electrode arrays on plastic substrates is elusive, we devised a fabrication and low-temperature sintering (\(\approx 200 ^\circ C\)) technique to print gold electrodes. Utilizing the versatility of printing and plastic electronic processes, electrode arrays were fabricated and used for impedance mapping of conformal surfaces at 15 kHz [1].

A more direct application of the array was to non-invasively map pressure-induced tissue damage. Here, the array was used to detect pressure ulcers in an animal model, even before the damages were observed visually. Our results demonstrated the feasibility of an automated, non-invasive “smart bandage” for early detection of pressure ulcers [2]. Moreover, for a different project, we used the gold electrodes printed on a wearable sensor patch as electrocardiography (ECG) electrodes.

Relevant publications:

  1. Inkjet-printed flexible gold electrode arrays for bioelectronic interfaces Yasser Khan*, Felippe J Pavinatto*, Monica C Lin, Amy Liao, Sarah L Swisher, Kaylee Mann, Vivek Subramanian, Michel M Maharbiz, and Ana C Arias Advanced Functional Materials, 2016 26, 7. Cover article.

    Bioelectronic interfaces require electrodes that are mechanically flexible and chemically inert. Flexibility allows pristine electrode contact to skin and tissue, and chemical inertness prevents electrodes from reacting with biological fluids and living tissues. Therefore, flexible gold electrodes are ideal for bioimpedance and biopotential measurements such as bioimpedance tomography, electrocardiography (ECG), electroencephalography (EEG), and electromyography (EMG). However, a manufacturing process to fabricate gold electrode arrays on plastic substrates is still elusive. In this work, a fabrication and low-temperature sintering (≈200 °C) technique is demonstrated to fabricate gold electrodes. At low-temperature sintering conditions, lines of different widths demonstrate different sintering speeds. Therefore, the sintering condition is targeted toward the widest feature in the design layout. Manufactured electrodes show minimum feature size of 62 μm and conductivity values of 5 × 10 6 S m−1. Utilizing the versatility of printing and plastic electronic processes, electrode arrays consisting of 31 electrodes with electrode-to-electrode spacing ranging from 2 to 7 mm are fabricated and used for impedance mapping of conformal surfaces at 15 kHz. Overall, the fabrication process of an inkjet-printed gold electrode array that is electrically reproducible, mechanically robust, and promising for bioimpedance and biopotential measurements is demonstrated.

    @article{khan2016inkjet, title = {Inkjet-printed flexible gold electrode arrays for bioelectronic interfaces}, author = {Khan*, Yasser and Pavinatto*, Felippe J and Lin, Monica C and Liao, Amy and Swisher, Sarah L and Mann, Kaylee and Subramanian, Vivek and Maharbiz, Michel M and Arias, Ana C}, journal = {Advanced Functional Materials}, volume = {26}, number = {7}, pages = {1004--1013}, year = {2016}, publisher = {Wiley Online Library}, url = {http://dx.doi.org/10.1002/adfm.201503316}, doi = {10.1002/adfm.201503316}, thumbnail = {khan2016inkjet.png}, pdf = {khan2016inkjet.pdf}, note = {Cover article.} }

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  1. Impedance sensing device enables early detection of pressure ulcers in vivo Sarah L Swisher, Monica C Lin, Amy Liao, Elisabeth J Leeflang, Yasser Khan, Felippe J Pavinatto, Kaylee Mann, Agne Naujokas, David Young, Shuvo Roy, Michael R Harrison, Ana C Arias, Vivek Subramanian, and Michel M Maharbiz Nature communications, 2015 6, Media coverage: BBC News, UC Berkeley News Center, Futurity, NSF News, ACM Communications, and many more.

    When pressure is applied to a localized area of the body for an extended time, the resulting loss of blood flow and subsequent reperfusion to the tissue causes cell death and a pressure ulcer develops. Preventing pressure ulcers is challenging because the combination of pressure and time that results in tissue damage varies widely between patients, and the underlying damage is often severe by the time a surface wound becomes visible. Currently, no method exists to detect early tissue damage and enable intervention. Here we demonstrate a flexible, electronic device that non-invasively maps pressure-induced tissue damage, even when such damage cannot be visually observed. Using impedance spectroscopy across flexible electrode arrays in vivo on a rat model, we find that impedance is robustly correlated with tissue health across multiple animals and wound types. Our results demonstrate the feasibility of an automated, non-invasive ‘smart bandage’ for early detection of pressure ulcers.

    @article{swisher2015impedance, title = {Impedance sensing device enables early detection of pressure ulcers in vivo}, author = {Swisher, Sarah L and Lin, Monica C and Liao, Amy and Leeflang, Elisabeth J and Khan, Yasser and Pavinatto, Felippe J and Mann, Kaylee and Naujokas, Agne and Young, David and Roy, Shuvo and Harrison, Michael R and Arias, Ana C and Subramanian, Vivek and Maharbiz, Michel M}, journal = {Nature communications}, volume = {6}, pages = {6575}, year = {2015}, publisher = {Nature Publishing Group}, url = {http://dx.doi.org/10.1038/ncomms7575}, doi = {10.1038/ncomms7575}, thumbnail = {swisher2015impedance.png}, pdf = {swisher2015impedance.pdf}, note = {Media coverage: }, media_1 = {BBC News, }, media_1_link = {http://www.bbc.com/news/health-31903367}, media_2 = {UC Berkeley News Center, }, media_2_link = {http://newscenter.berkeley.edu/2015/03/17/smart-bandages-detect-bedsores/}, media_3 = {Futurity, }, media_3_link = {http://www.futurity.org/smart-bandage-bedsores-876942/}, media_4 = {NSF News, }, media_4_link = {https://www.nsf.gov/news/news_summ.jsp?cntn_id=134610}, media_5 = {ACM Communications, }, media_5_link = {https://cacm.acm.org/news/184717-smart-bandage-detects-bedsores-before-they-are-visible-to-doctors/fulltext}, media_6 = {and many more.}, media_6_link = {https://www.altmetric.com/details/3798805} }

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Last modified: 2018-01-02