Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Sep 2:8:96.
doi: 10.1038/s41378-022-00433-8. eCollection 2022.

Electrochemical and biological performance of hierarchical platinum-iridium electrodes structured by a femtosecond laser

Linze Li  1   2 , Changqing Jiang  1 , Wanru Duan  3   4 , Zhiyan Wang  1 , Feng Zhang  1 , Changgeng He  1 , Tiangang Long  1 , Luming Li  1   5   6   7
Affiliations

Electrochemical and biological performance of hierarchical platinum-iridium electrodes structured by a femtosecond laser

Linze Li et al. Microsyst Nanoeng. .

Abstract

Neural electrode interfaces are essential to the stimulation safety and recording quality of various bioelectronic therapies. The recently proposed hierarchical platinum-iridium (Pt-Ir) electrodes produced by femtosecond lasers have exhibited superior electrochemical performance in vitro, but their in vivo performance is still unclear. In this study, we explored the electrochemical performance, biological response, and tissue adhesion of hierarchical Pt-Ir electrodes by implantation in adult rat brains for 1, 8, and 16 weeks. Regular smooth Pt-Ir electrodes were used as a control. The results showed that the electrochemical performance of both electrodes decreased and leveled off during implantation. However, after 16 weeks, the charge storage capacity of hierarchical electrodes stabilized at ~16.8 mC/cm2, which was 15 times that of the smooth control electrodes (1.1 mC/cm2). Moreover, the highly structured electrodes had lower impedance amplitude and cutoff frequency values. The similar histological response to smooth electrodes indicated good biocompatibility of the hierarchically structured Pt-Ir electrodes. Given their superior in vivo performance, the femtosecond laser-treated Pt-Ir electrode showed great potential for neuromodulation applications.

Keywords: Electrical and electronic engineering; Nanostructures.

PubMed Disclaimer

Conflict of interest statement

Competing interestsThe authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Study overview.
a Smooth and hierarchical Pt-Ir electrode surfaces (sPt-Ir and hPt-Ir). PU polyurethane. b Fixation base of the electrode. c X-ray photo of the implanted electrode. d Experimental design. WE working electrode, RE reference electrode, CE counter electrode, CV cyclic voltammetry, EIS electrochemical impedance spectrum, HE hematoxylin–eosin staining, IHC immunohistochemistry, SEM scanning electron microscopy.
Fig. 2
Fig. 2. Weekly body weight.
Rats implanted for a 1 week, b 8 weeks and c 16 weeks.
Fig. 3
Fig. 3. Electrochemical performance results.
a Cyclic voltammetry curves of sPt-Ir and hPt-Ir at 0 and 16 weeks. b In vitro and in vivo charge storage capacity (CSC). The inset shows the trend of normalized CSC varying with implantation time compared to the in vitro value. c In vitro and in vivo electrochemical impedance spectra. An asterisk (*) denotes p < 0.05 (one-way ANOVA).
Fig. 4
Fig. 4. Histological results.
a HE, Iba-1, GFAP, and NeuN staining of the tissue surrounding the electrodes at 1, 8, and 16 weeks after implantation. b Normalized neurons count with increasing distance from the electrode interface.
Fig. 5
Fig. 5. Scanning electron microscopy of electrodes surfaces.
The sPt-Ir and hPt-Ir electrodes surfaces a as processed and after b 1 week, c 8 weeks, and d 16 weeks of implantation.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Cogan SF. Neural stimulation and recording electrodes. Annu. Rev. Biomed. Eng. 2008;10:275–309. doi: 10.1146/annurev.bioeng.10.061807.160518. - DOI - PubMed
    1. Jiang C, Li L, Hao H. Carbon nanotube yarns for deep brain stimulation electrode. IEEE Trans. Neural Syst. Rehabil. Eng. 2011;19:612–616. doi: 10.1109/TNSRE.2011.2165733. - DOI - PubMed
    1. Cowley A, Woodward B. A healthy future: platinum in medical applications. Platin. Met. Rev. 2011;55:98–107. doi: 10.1595/147106711X566816. - DOI
    1. Vedam-Mai, V. et al. Proceedings of the eighth annual deep brain stimulation think tank: advances in optogenetics, ethical issues affecting DBS Research, neuromodulatory approaches for depression, adaptive neurostimulation, and emerging DBS technologies. Front. Hum. Neurosci. 15, 765150 (2021). - PMC - PubMed
    1. Steigerwald F, Matthies C, Volkmann J. Directional deep brain stimulation. Neurotherapeutics. 2019;16:100–104. doi: 10.1007/s13311-018-0667-7. - DOI - PMC - PubMed