Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
권호 표지
DOI QR코드

DOI QR Code

Fabrication of a Moldable, Long-Term Stable, High-Performance Conductive Hydrogel Composed of Biocompatible Materials

생체친화적 재료로 구성된 성형 가능하고 장시간 안정성을 지닌 고성능 전도성 하이드로겔 제작

  • Seon Young Lee (Department of Chemical Engineering, Pukyong National University) ;
  • Hocheon Yoo (Department of Electronic Engineering, Gachon University) ;
  • Eun Kwang Lee (Department of Chemical Engineering, Pukyong National University)
  • 이선영 (부경대학교 화학공학과) ;
  • 유호천 (가천대학교 전자공학과) ;
  • 이은광 (부경대학교 화학공학과)
  • Received : 2024.07.22
  • Accepted : 2024.08.13
  • Published : 2024.10.10
Download PDF
⟨ Previous Next ⟩

Abstract

The entire process of producing a conductive hydrogel for use as electrodes, such as in biomedical applications like electrocardiogram (ECG) and electromyogram (EMG), was conducted through a one-pot synthesis method where all reactions took place within a single reactor. In this study, the poly-(Hydroxyethyl methacrylate) (pHEMA)/Chitosan (CS) hydrogel was fabricated with improved functionality by incorporating phytic acid (PA). For a pHEMA hydrogel without PA, the functionality was 47.8%, while the pHEMA/CS/PA-200 hydrogel with 0.2 mL of PA exhibited a functionality of 67.8%, indicating an increase of approximately 20%. As the PA content increased to 0.025, 0.05, and 0.2 mL, the ionic conductivity also increased to 0.057, 0.14, and 1.5 S/m, respectively. Notably, the HCP-200 hydrogel showed a conductivity 104 times greater than the pHEMA hydrogel. Therefore, the HCP-200 hydrogel, among the three concentrations, was synthesized for further testing, including shaping and direct attachment to three electrodes for subsequent ECG and EMG signal analysis. In the case of ECG, the signal peak heights were similar for the existing electrodes, Ag/AgCl and HCP gel. The average value of the EMG signal peak height was approximately 4 times higher for HCP gel.

전극으로 사용할 전도성 하이드로겔을 제작하는 일련의 과정은 한 반응기 내에서 모든 반응이 진행되는 one-pot synthesis 방법으로 진행되었다. 본 연구에서는 심전도(electrocardiogram, ECG), 심근도(electromyogram, EMG) 전극과 같은 생체 전극에 활용하기 위한 poly-(hydroxyethyl methacrylate) (pHEMA)/chitosan (CS) 하이드로겔에 phytic acid (PA) 첨가를 통해 함수율을 향상시킨 형태로 제작하였다. PA를 함유하지 않은 pHEMA 하이드로겔의 경우 함수율이 47.8%, PA의 함량이 0.2 mL인 pHEMA/CS/PA-200 (HCP-200) 하이드로겔의 경우 67.8%으로 함수율이 약 20% 증가한 것으로 나타났다. PA의 함량이 0.025, 0.05, 0.2 mL로 증가할 때 이온 전도도는 각각 0.057, 0.14, 1.5 S/m로 증가하였고, pHEMA 하이드로겔 대비 HCP-200 하이드로겔이 전도도 성능이 104배 큰 수치를 보였다. 이를 이용해 세 농도의 하이드로겔 중 HCP-200을 합성하여 성형 가능성을 확인하고, 이를 활용해 3전극 시스템 ECG, EMG 신호에 대한 결과를 분석하였다. ECG의 경우 신호 피크의 높이가 기존 전극인 Ag/AgCl과 HCP 겔이 유사하게 나타났다. EMG 신호 피크가 HCP 겔이 약 4배 높은 값을 보였다.

Keywords

Acknowledgement

이 연구는 한국 정부가 지원하는 한국연구재단(NRF) 지원금(RS-2023-00213534) 및 교육부에서 지원하는 지역혁신전략(RIS) 프로젝트(2023RIS-007)의 일환과 국립부경대학교 자율창의학술연구비(2024년)에 의하여 연구으로 수행되었음.

References

  1. W. Shi, Y. Guo, and Y. Liu, When flexible organic field-effect transistors meet biomimetics: A prospective view of the internet of things, Adv. Mater., 32, 1901493 (2020).
  2. C. Xu, D. Jiang, Y. Ge, L. Huang, Y. Xiao, X. Ren, X. Liu, Q. Zhang, and Y. Wang, A PEDOT:PSS conductive hydrogel incorporated with Prussian blue nanoparticles for wearable and noninvasive monitoring of glucose, Chem. Eng. J., 431, 134109 (2022).
  3. J. Yoo, L. Yan, S. Lee, H. Kim, and H. J. Yoo, A wearable ECG acquisition system with compact planar-fashionable circuit boardbased shirt, IEEE Trans. Inf. Technol. Biomed., 13, 897-902 (2009).
  4. Y. Hong, Z. Lin, Y. Yang, T. Jiang, J. Shang, and Z. Luo, Biocompatible conductive hydrogels: Applications in the field of biomedicine, Int. J. Mol. Sci., 23, 4578 (2022).
  5. Y. Zhang, Q. Tang, J. Zhou, C. Zhao, J. Li, H. Wang, Conductive and eco-friendly biomaterials-based hydrogels for noninvasive epidermal sensors: A review, ACS Biomater. Sci. Eng., 10, 191-218 (2024).
  6. G. Kougkolos, M. Golzio, L. Laudebat, Z. Valdez-Nava, and E. Flahaut, Hydrogels with electrically conductive nanomaterials for biomedical applications, J. Mater. Chem. B, 11, 2036-2062 (2023).
  7. K. Nagamine, S. Chihara, H. Kai, H. Kaji, and M. Nishizawa, Totally shape-conformable electrode/hydrogel composite for on-skin electrophysiological measurements, Sens. Actuators B Chem., 237, 49-53 (2016).
  8. F. Ghorbanizamani, H. Moulahoum, E. Guler Celik, and S. Timur, Ionic liquids enhancement of hydrogels and impact on biosensing applications, J. Mol. Liq., 357, 119075 (2022).
  9. Q. Zhang, X. Liu, J. Zhang, L. Duan, and G. Gao, A highly conductive hydrogel driven by phytic acid towards a wearable sensor with freezing and dehydration resistance, J. Mater. Chem. A, 9, 22615-22625 (2021).
  10. W. Liu, R. Xie, J. Zhu, J. Wu, J. Hui, X. Zheng, F. Huo, and D. Fan, A temperature responsive adhesive hydrogel for fabrication of flexible electronic sensors, npj Flex. Electron., 6, 68 (2022).
  11. D. Lee, S. Cho, H. S. Park, and I. Kwon, Ocular drug delivery through pHEMA-hydrogel contact lenses co-loaded with lipophilic vitamins, Sci. Rep., 6, 34194 (2016).
  12. V. Manigandan, R. Karthik, S. Ramachandran, and S. Rajagopal, Chitosan applications in food industry. In: A. M. Grumezescu and A. M. Holban (eds.). Biopolymers for Food Design, 469-491, Academic Press, Cambridge, Massachusetts, United States (2018).
  13. E. Graf and J. W. Eaton, Antioxidant functions of phytic acid, Free Radical Biol. Med., 8, 61-69 (1990).
  14. Z. Wang, Y. C. Lai, Y. T. Chiang, J. M. Scheiger, S. Li, Z. Dong, Q. Cai, S. Liu, S. H. Hsu, C. C. Chou, and P. A. Levkin, Tough, self-healing, and conductive elastomer ionic peggel, ACS Appl. Mater. Interfaces, 14, 50152-50162 (2022).
  15. C. Yang, Q. Wu, J. Liu, J. Mo, X. Li, C. Yang, Z. Liu, J. Yang, L. Jiang, W. Chen, H. J. Chen, J. Wang, and X. Xie, Intelligent wireless theranostic contact lens for electrical sensing and regulation of intraocular pressure, Nat. Commun., 13, 2556 (2022).
  16. Y. Shi, Y. Ding, W. Wang, and D. Yu, High performance zwitterionic hydrogels for ECG/EMG signals monitoring, Colloids Surf. A: Physicochem. Eng. Asp., 675, 132081 (2023).
  17. Y. M. Gao, Z. Y. Li, X. J. Zhang, J. Zhang, Q. F. Li, and S. B. Zhou, One-pot synthesis of bioadhesive double-network hydrogel patch as disposable wound dressing, ACS Appl. Mater. Interfaces, 15, 11496-11506 (2023).
  18. N. Thakur, A. Chaudhary, A. Chakraborty, R. Kumar, and T. K. Sarma, Ion conductive phytic acid-G quadruplex hydrogel as electrolyte for flexible electrochromic device, ChemNanoMat, 7, 613-619 (2021).
  19. N. B. Alsaafeen, S. S. Bawazir, K. K. Jena, A. Seitak, B. Fatma, C. Pitsalidis, A. Khandoker, and A. M. Pappa, One-pot synthesis of a robust crosslinker-free thermo-reversible conducting hydrogel electrode for epidermal electronics, ACS Appl. Mater. Interfaces, Doi:10.1021/acsami.3c10663.
  20. C. Liu, R. Zhang, Y. Wang, J. Qu, J. Huang, M. Mo, N. Qing, and L. Tang, Tough, anti-drying and thermoplastic hydrogels consisting of biofriendly resources for a wide linear range and fast response strain sensor, J. Mater. Chem. A, 11, 2002-2013 (2023).
  21. J. Hua, M. Su, X. Sun, J. Li, Y. Sun, H. Qiu, Y. Shi, and L. Pan, Hydrogel-based bioelectronics and their applications in health monitoring, Biosensors, 13, 696 (2023).
  22. M. W. Tibbitt, A. M. Kloxin, L. A. Sawicki, and K. S. Anseth, Mechanical properties and degradation of chain and step-polymerized photodegradable hydrogels, Macromolecules, 46, 2785-2792 (2013).
  23. B. Pejcic and R. De Marco, Impedance spectroscopy: Over 35 years of electrochemical sensor optimization, Electrochim. Acta, 51, 6217-6229 (2006).
  24. K. H. Lee, S. Zhang, T. P. Lodge, and C. D. Frisbie, Electrical impedance of spin-coatable ion gel films, J. Phys. Chem. B, 115, 3315-3321 (2011).
  25. S. Zhang, K. H. Lee, C. D. Frisbie, and T. P. Lodge, Ionic conductivity, capacitance, and viscoelastic properties of block copolymer-based ion gels, Macromolecules, 44, 940-949 (2011).
  26. D. Lou, C. Wang, Z. He, X. Sun, J. Luo, and J. Li, Robust organohydrogel with flexibility and conductivity across the freezing and boiling temperatures of water, Chem. Commun., 55, 8422-8425 (2019).
  27. J. Zhang, Q. Wang, and Z. Cao, Effects of water on the structure and transport properties of room temperature ionic liquids and concentrated electrolyte solutions, Chin. Phys. B, 29, 087804 (2020).
  28. Y. Wang, Q. Li, H. Hong, S. Yang, R. Zhang, X. Wang, X. Jin, B. Xiong, S. Bai, and C. Zhi, Lean-water hydrogel electrolyte for zinc ion batteries, Nat. Commun., 14, 3890 (2023).
  29. X. He, S. Yang, Q. Pei, Y. Song, C. Liu, T. Xu, and X. Zhang, Integrated smart janus textile bands for self-pumping sweat sampling and analysis, ACS Sensors, 5, 1548-1554 (2020).