Gelatin methacryloyl-based tactile sensors for medical wearables

Zhikang Li; Shiming Zhang; Yihang Chen; Haonan Ling; Libo Zhao; Guoxi Luo; Xiaocheng Wang; Martin C Hartel; Hao Liu; Yumeng Xue; Reihaneh Haghniaz; KangJu Lee; Wujin Sun; Hanjun Kim; Junmin Lee; Yichao Zhao; Yepin Zhao; Sam Emaminejad; Samad Ahadian; Nureddin Ashammakhi; Mehmet R Dokmeci; Zhuangde Jiang; Ali Khademhosseini

doi:10.1002/adfm.202003601

Gelatin methacryloyl-based tactile sensors for medical wearables

Adv Funct Mater. 2020 Dec 1;30(49):2003601. doi: 10.1002/adfm.202003601. Epub 2020 Sep 6.

Authors

Zhikang Li^{1

2

3

4

5

6}, Shiming Zhang^{1

2

3}, Yihang Chen^{1

2

3}, Haonan Ling^{1

2

3

7}, Libo Zhao^{4

5

6}, Guoxi Luo^{4

5

6}, Xiaocheng Wang^{1

2

3

8}, Martin C Hartel^{1

2

3}, Hao Liu^{1

2

3

9}, Yumeng Xue^{1

2

3

10}, Reihaneh Haghniaz^{1

2

3}, KangJu Lee^{1

2

3}, Wujin Sun^{1

2

3}, Hanjun Kim^{1

2

3}, Junmin Lee^{1

2

3}, Yichao Zhao¹¹, Yepin Zhao^{3

12}, Sam Emaminejad¹¹, Samad Ahadian^{1

2

3}, Nureddin Ashammakhi^{1

2

3

13}, Mehmet R Dokmeci^{1

2

3

13}, Zhuangde Jiang^{4

5

6}, Ali Khademhosseini^{1

2

3

13

14

15}

Affiliations

¹ Department of Bioengineering, University of California-Los Angeles, Los Angeles, CA 90095, USA.
² Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA 90095, USA.
³ California NanoSystems Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA.
⁴ School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
⁵ State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
⁶ International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi'an Jiaotong University, Xi'an, 710049, China.
⁷ Department of Mechanical and Aerospace Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA.
⁸ School of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310000, China.
⁹ Ministry of education key laboratory of biomedical information engineering, Xi'an Jiaotong University, Xi'an 710049, China.
¹⁰ Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
¹¹ Department of Electrical and Computer Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA.
¹² Department of Materials Science and Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA.
¹³ Department of Radiology, University of California-Los Angeles, Los Angeles, CA 90095, USA.
¹⁴ Department of Chemical and Biomolecular Engineering, University of California-Los Angeles, Los Angeles, CA 90095, USA.
¹⁵ Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90024, USA.

Abstract

Gelatin methacryloyl (GelMA) is a widely used hydrogel with skin-derived gelatin acting as the main constituent. However, GelMA has not been used in the development of wearable biosensors, which are emerging devices that enable personalized healthcare monitoring. This work highlights the potential of GelMA for wearable biosensing applications by demonstrating a fully solution-processable and transparent capacitive tactile sensor with microstructured GelMA as the core dielectric layer. A robust chemical bonding and a reliable encapsulation approach are introduced to overcome detachment and water-evaporation issues in hydrogel biosensors. The resultant GelMA tactile sensor shows a high-pressure sensitivity of 0.19 kPa^-1 and one order of magnitude lower limit of detection (0.1 Pa) compared to previous hydrogel pressure sensors owing to its excellent mechanical and electrical properties (dielectric constant). Furthermore, it shows durability up to 3000 test cycles because of tough chemical bonding, and long-term stability of 3 days due to the inclusion of an encapsulation layer, which prevents water evaporation (80% water content). Successful monitoring of various human physiological and motion signals demonstrates the potential of these GelMA tactile sensors for wearable biosensing applications.

Keywords: GelMA hydrogel; Healthcare; Interface adhesion; PEDOT: PSS, Transparency; Solution-processable; Wearable tactile sensors.

Abstract

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