Materials and Methods

  • Tae Mok GwonEmail author
Part of the Springer Theses book series (Springer Theses)


Biocompatible polymers such as polyimide, parylene-C, SU-8, and silicone elastomer have gained great interests in neural implants due to their flexibility and compatibility with micro-fabrication. In recent studies, polymer-based or hybrid with conventional neural implants have been developed and evaluated for clinical uses (Kim et al. in Invest Ophthalmol Vis Sci 50:4337–4341, 2009 [1]. Polyimides have been widely used as insulation and substrate materials for medical devices. Polyimides can be used bulk film type or spun onto thin films as both photopatternable and non-photopatternable types. Polyimides are mainly served as substrates of flexible microelectrode arrays including cuff electrodes for peripheral nerve stimulation and micro-channel for nerve regeneration, and insulation materials for MEMS sensor. Moreover, high light transmittance property with wide range of wavelengths enable polyimide to be an optoelectronics material. Parylene-C has very low water absorption rate and chemical inertness. Chemical vapor deposition (CVD) process without any additives is needed to deposit parylene-C onto biomedical devices. It is mostly used as a coating material for implantable devices because a few micrometer of insulation layer is possible using parylene-C. SU-8 in MEMS have been famous due to its patternable property using photolithography and various types with usable thickness ranging from a few to hundreds of µm. Tunable electrical, mechanical, and optical properties make it more attractive biomaterials to be used in structural molds for soft lithography, optical waveguides, and neural probes.


  1. 1.
    E.T. Kim, C. Kim, S.W. Lee, J.-M. Seo, H. Chung, S.J. Kim, Feasibility of Microelectrode Array (MEA) based on silicone-polyimide hybrid for retina prosthesis. Invest. Ophthalmol. Vis. Sci. 50, 4337–4341 (2009)CrossRefGoogle Scholar
  2. 2.
    S.W. Lee, J. Jeong, K.S. Min, S. Shin, S.B. Jun, S.J. Kim, Liquid crystal polymer (LCP), an attractive substrate for retinal implant, Sens. Mater. 24, 2012Google Scholar
  3. 3.
    J. Jeong, S. Shin, G.J. Lee, T.M. Gwon, J.H. Park, S.J. Kim, Advancements in fabrication process of microelectrode array for a retinal prosthesis using liquid crystal polymer (LCP), in 2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (2013), pp. 5295–5298Google Scholar
  4. 4.
    S.W. Lee, K.S. Min, J. Jeong, J. Kim, S.J. Kim, Monolithic encapsulation of implantable neuroprosthetic devices using liquid crystal polymers, IEEE Transactions on Biomedical Engineering, vol. 58, 2011Google Scholar
  5. 5.
    J. Jeong, S.H. Bae, K.S. Min, J.M. Seo, H. Chung, S.J. Kim, A miniaturized, eye-conformable, and long-term reliable retinal prosthesis using monolithic fabrication of Liquid crystal polymer (LCP). IEEE Trans. Biomed. Eng. 62, 982–989 (2015)CrossRefGoogle Scholar
  6. 6.
    K.S. Min, S.H. Oh, M.H. Park, J. Jeong, S.J. Kim, A polymer-based multichannel cochlear electrode array. Otol. Neurotol. 35, 1179–1186 (2014)Google Scholar
  7. 7.
    E.Y. Chow, A.L. Chlebowski, P.P. Irazoqui, A miniature-implantable RF-wireless active glaucoma intraocular pressure monitor. IEEE Trans. Biomed. Circuits Syst. 4, 340–349 (2010)CrossRefGoogle Scholar
  8. 8.
    T. Gwon, K. Min, J. Kim, S. Oh, H. Lee, M.-H. Park et al., Fabrication and evaluation of an improved polymer-based cochlear electrode array for atraumatic insertion. Biomed. Microdevice 17, 1–12 (2015)CrossRefGoogle Scholar
  9. 9.
    G.-T. Hwang, D. Im, S.E. Lee, J. Lee, M. Koo, S.Y. Park et al., In vivo silicon-based flexible radio frequency integrated circuits monolithically encapsulated with biocompatible liquid crystal polymers. ACS Nano. 7, 4545–4553 (2013)CrossRefGoogle Scholar
  10. 10.
    N. Laotaveerungrueng, C.H. Lin, G. McCallum, S. Rajgopal, C.P. Steiner, A.R. Rezai, et al., 3-D microfabricated electrodes for targeted deep brain stimulation, in 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society (2009), pp. 6493–6496Google Scholar
  11. 11.
    S.W. Lee, J.M. Seo, S. Ha, E.T. Kim, H. Chung, S.J. Kim, Development of microelectrode arrays for artificial retinal implants using liquid crystal polymers. Invest. Ophthalmol. Vis. Sci. 50, 5859–5866 (2009)CrossRefGoogle Scholar
  12. 12.
    C. Liu, Recent Developments in Polymer MEMS. Adv. Mater. 19, 3783–3790 (2007)CrossRefGoogle Scholar
  13. 13.
    P. Sattayasoonthorn, J. Suthakorn, S. Chamnanvej, J. Miao, A.G.P. Kottapalli, LCP MEMS implantable pressure sensor for intracranial pressure measurement, in 2013 IEEE 7th International Conference on Nano/Molecular Medicine and Engineering (NANOMED) (2013), pp. 63–67Google Scholar
  14. 14.
    S.E. Lee, S.B. Jun, H.-J. Lee, J. Kim, S.W. Lee, H.-C. Shin, J.W. Chang, S.J. Kim, A flexible depth probe using liquid crystal polymer. IEEE Trans. Biomed. Eng. 59, 2085–2094 (2012)CrossRefGoogle Scholar
  15. 15.
    W. Xuefeng, E. Jonathan, L. Chang, Liquid crystal polymer (LCP) for MEMS: processes and applications. J. Micromech. Microeng. 13, 628 (2003)CrossRefGoogle Scholar
  16. 16.
    J.H. Kim, K.S. Min, S.K. An, J.S. Jeong, S.B. Jun, M.H. Cho et al., Magnetic resonance imaging compatibility of the polymer-based cochlear implant. Clin. Exp. Otorhinolaryngol. 5, S19–S23 (2012)CrossRefGoogle Scholar
  17. 17.
    J. Jeong, S.H. Bae, J.-M. Seo, H. Chung, S.J. Kim, Long-term evaluation of a liquid crystal polymer (LCP)-based retinal prosthesis. J. Neural Eng. 13, 025004 (2016)ADSCrossRefGoogle Scholar
  18. 18.
    S.H. Bae, J.-H. Che, J.-M. Seo, J. Jeong, E.T. Kim, S.W. Lee, K.-I. Koo, G.J. Suaning, N.H. Lovell, D.-I. Cho, S.J. Kim, H. Chung, In vitro biocompatibility of various polymer-based microelectrode arrays for retinal prosthesismicroelectrode arrays for retinal prosthesis. Invest. Ophthalmol. Vis. Sci. 53, 2653–2657 (2012)CrossRefGoogle Scholar
  19. 19.
    T.M. Gwon, J.H. Kim, G.J. Choi, S.J. Kim, Mechanical interlocking to improve metal–polymer adhesion in polymer-based neural electrodes and its impact on device reliability. J. Mater. Sci. 51, 6897–6912 (2016)ADSCrossRefGoogle Scholar
  20. 20.
    T.M. Gwon, C. Kim, S. Shin, J.H. Park, J.H. Kim, S.J. Kim, Liquid crystal polymer (LCP)-based neural prosthetic devices. Biomed. Eng. Lett. 6, 148–163 (2016)CrossRefGoogle Scholar
  21. 21.
    A.L. Chlebowski, Advanced radio frequency materials for packaging of implantable biomedical devices, 2009Google Scholar
  22. 22.
    J.R.N. Dean, J. Weller, M.J. Bozack, C.L. Rodekohr, B. Farrell, L. Jauniskis et al., Realization of ultra fine pitch traces on LCP substrates. IEEE Trans. Compon. Packag. Technol. 31, 315–321 (2008)CrossRefGoogle Scholar
  23. 23.
    C. Hassler, T. Boretius, T. Stieglitz, Polymers for neural implants. J. Polym. Sci., Part B: Polym. Phys. 49, 18–33 (2011)ADSCrossRefGoogle Scholar
  24. 24.
    R. Pelrine, R. Kornbluh, J. Joseph, R. Heydt, Q. Pei, S. Chiba, High-field deformation of elastomeric dielectrics for actuators. Mater. Sci. Eng., C 11, 89–100 (2000)CrossRefGoogle Scholar
  25. 25.
    A.D. Woolfson, R.K. Malcolm, S.P. Gorman, D.S. Jones, A.F. Brown, S.D. McCullagh, Self-lubricating silicone elastomer biomaterials. J. Mater. Chem. 13, 2465–2470 (2003)CrossRefGoogle Scholar
  26. 26.
    K.S. Min, “A study on the liquid crystal polymer-based intracochlear electrode array,” Thesis Seoul National University, 2014Google Scholar
  27. 27.
    A.A. Eshraghi, N.W. Yang, T.J. Balkany, Comparative study of cochlear damage with three perimodiolar electrode designs. The Laryngoscope 113, 415–419 (2003)CrossRefGoogle Scholar
  28. 28.
    A. Fedorov, R. Beichel, J. Kalpathy-Cramer, J. Finet, J-C. Fillion-Robin, S. Pujol, C. et al., Kikinis. 3D Slicer as an Image Computing Platform for the Quantitative Imaging Network. Magn. Reson. Imaging. 30(9), 1323–1341. PMID: 22770690 (2012)CrossRefGoogle Scholar
  29. 29.
    M. Polak, A.A. Eshraghi, O. Nehme, S. Ahsan, J. Guzman, R.E. Delgado et al., Evaluation of hearing and auditory nerve function by combining ABR, DPOAE and eABR tests into a single recording session. J. Neurosci. Methods 134, 141–149 (2004)CrossRefGoogle Scholar
  30. 30.
    C.A. Schneider, W.S. Rasband, K.W. Eliceiri, NIH image to imageJ: 25 years of image analysis. Nature methods 9(7), 671–675 (2012)CrossRefGoogle Scholar
  31. 31.
    B.H. Bonham, L.M. Litvak, Current focusing and steering: modeling, physiology, and psychophysics. Hear. Res. 242, 141–153 (2008)CrossRefGoogle Scholar
  32. 32.
    J.H. Park, C. Kim, S.H. Ahn, T.M. Gwon, J. Jeong, S. Beom Jun, S.J. Kim, A distributed current stimulator ASIC for high density neural stimulation, in 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2016Google Scholar
  33. 33.
    A. Leng, H. Streckel, K. Hofmann, M. Stratmann, The delamination of polymeric coatings from steel Part 3: effect of the oxygen partial pressure on the delamination reaction and current distribution at the metal/polymer interface. Corros. Sci. 41, 599–620 (1998)CrossRefGoogle Scholar
  34. 34.
    A. Leng, H. Streckel, M. Stratmann, The delamination of polymeric coatings from steel. Part 2: first stage of delamination, effect of type and concentration of cations on delamination, chemical analysis of the interface. Corros. Sci. 41, 579–597 (1998)CrossRefGoogle Scholar
  35. 35.
    A. Leng, H. Streckel, M. Stratmann, The delamination of polymeric coatings from steel. Part 1: Calibration of the Kelvinprobe and basic delamination mechanism. Corros. Sci. 41, 547–578 (1998)CrossRefGoogle Scholar
  36. 36.
    A. Vanhoestenberghe, N. Donaldson, The limits of hermeticity test methods for micropackages. Artif. Organs 35, 242–244 (2011)CrossRefGoogle Scholar
  37. 37.
    K. Aihara, M.J. Chen, C. Cheng, A.V.H. Pham, Reliability of liquid crystal polymer air cavity packaging. IEEE Trans. Compon. Packag. Manuf. Technol. 2, 224–230 (2012)CrossRefGoogle Scholar
  38. 38.
    A.-V. Pham, Packaging with liquid crystal polymer. IEEE Microwave Mag. 5, 83–91 (2011)CrossRefGoogle Scholar
  39. 39.
    W.-S. Kim, I.-H. Yun, J.-J. Lee, H.-T. Jung, Evaluation of mechanical interlock effect on adhesion strength of polymer–metal interfaces using micro-patterned surface topography. Int. J. Adhes. Adhes. 30, 408–417 (2010)CrossRefGoogle Scholar
  40. 40.
    F.K. LeGoues, B.D. Silverman, P.S. Ho, The microstructure of metal–polyimide interfaces. J. Vac. Sci. Technol., A 6, 2200–2204 (1988)ADSCrossRefGoogle Scholar
  41. 41.
    D.E. Packham, Surface energy, surface topography and adhesion. Int. J. Adhes. Adhes. 23, 437–448 (2003)CrossRefGoogle Scholar
  42. 42.
    J.D. Venables, Adhesion and durability of metal-polymer bonds. J. Mater. Sci. 19, 2431–2453 (1984)ADSCrossRefGoogle Scholar
  43. 43.
    J.F. McCabe, T.E. Carrick, H. Kamohara, Adhesive bond strength and compliance for denture soft lining materials. Biomaterials 23, 1347–1352 (2002)CrossRefGoogle Scholar
  44. 44.
    W. Chun, N. Chou, S. Cho, S. Yang, S. Kim, Evaluation of sub-micrometer parylene C films as an insulation layer using electrochemical impedance spectroscopy. Prog. Org. Coat. 77, 537–547 (2014)CrossRefGoogle Scholar
  45. 45.
    E. Song, H. Fang, X. Jin, J. Zhao, C. Jiang, K.J. Yu et al., Thin, transferred layers of silicon dioxide and silicon nitride as water and ion barriers for implantable flexible electronic systems. Adv. Electron. Mater. 3, 1700077 (2017)CrossRefGoogle Scholar
  46. 46.
    D.S. Wuu, W.C. Lo, C.C. Chiang, H.B. Lin, L.S. Chang, R.H. Horng et al., Water and oxygen permeation of silicon nitride films prepared by plasma-enhanced chemical vapor deposition. Surf. Coat. Technol. 198, 114–117 (2005)CrossRefGoogle Scholar
  47. 47.
    S.J. Oh, J.K. Song, S.J. Kim, Neural interface with a silicon neural probe in the advancement of microtechnology. Biotechnol. Bioprocess Eng. 8, 252–256 (2003)CrossRefGoogle Scholar
  48. 48.
    A.U. Alam, Y. Qin, M.R. Howlader, M.J. Deen, Direct bonding of liquid crystal polymer to glass. RSC Adv. 6, 107200–107207 (2016)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.Department of Electrical and Computer EngineeringSeoul National UniversitySeoulKorea (Republic of)

Personalised recommendations