Bioelectronic, stretchable devices interfacing with the human body

Organic electronic devices have attracted particular attention in the last decades and established applications in organic light-emitting diodes have been realized. Besides low-temperature processes, low-cost and ease of processing, another significant advantage of organic devices are their mechanical flexibility and ductility. A flexible or stretchable architecture of organic devices can be plastered on skin, heart or brain tissue to monitor e.g. pressure or body movements. As a result, organic electronic devices have already been used to realize artificial electronic skin or wearable sensors. In recent years we have seen the rise of research on organic bioelectronics, where cells and tissues are demonstrated to directly interface with electronic devices via ionic signal communication. A combination of flexible/stretchable architectures with organic bioelectronics could lead to a mechanical compliance device which will be a promising candidate for future e-skin or e-health applications. However, device development on such materials presents several challenges. For flexible and stretchable substrates are not compatible with conventional photolithography techniques, which renders the fabrication of micro-scale devices difficult. In addition, all the processes involved in the flexible/stretchable bioelectronics device development should be environmentally friendly and the materials used should not contain any toxic ingredients since they will interface directly with cells and human body.

We realized micron-scale electrode arrays and patterned conducting polymer poly-(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonic acid) (PEDOT:PSS) channels on poly(dimethylsiloxane) (PDMS) substrates. Completely bio-compatible as well as stretchable organic electronic devices were finally developed using a new fabrication approach. Systematical studies were conducted on the composition of the conducting polymer, water immersion, channel thickness and PDMS pre-stretching to reveal their effect on stretchablity and device performance. Long-time film stability, frequency response and device fatigue is also discussed. According to these results, a reasonable device engineering guideline is finally proposed. The optimized device can be stretched up to nearly 100% with reversible I-V curves. Further studies show that these devices can work efficiently to interface with biological systems and living tissues or as tactile sensors.

References: [1] Rivnay J, Owens R M and Malliaras G G 2014 The Rise of Organic Bioelectronics Chemistry of Materials 26 679-85 [2] Cicoira F and Santato C 2013 Organic electronics: emerging concepts and technologies: John Wiley & Sons) [3] Bernards D A and Malliaras G G 2007 Steady‐state and transient behavior of organic electrochemical transistors Advanced Functional Materials 17 3538-44 [4] Lin P and Yan F 2012 Organic Thin‐Film Transistors for Chemical and Biological Sensing Advanced materials 24 34-51 [5] Campana A, Cramer T, Simon D T, Berggren M and Biscarini F 2014 Electrocardiographic recording with conformable organic electrochemical transistor fabricated on resorbable bioscaffold Advanced Materials 26 3874-8 [6] Stavrinidou E, Leleux P, Rajaona H, Khodagholy D, Rivnay J, Lindau M, Sanaur S and Malliaras G G 2013 Direct measurement of ion mobility in a conducting polymer Advanced Materials 25 4488-93

Mots clés

• Biomedical Engineering
• Polymers and Plastics
• Advanced Sensor and Energy Harvesting Materials
• Conducting polymers and applications