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Silver/silver chloride microneedles can detect penetration through the round window membrane
Author(s) -
Wazen Joseph M.,
Stevens James P.,
Watanabe Hirobumi,
Kysar Jeffrey W.,
Lalwani Anil K.
Publication year - 2017
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.33557
Subject(s) - penetration (warfare) , materials science , silver chloride , membrane , window (computing) , chloride , biomedical engineering , computer science , chemistry , metallurgy , world wide web , electrode , medicine , engineering , operations research , biochemistry
Hypothesis: Silver‐plated microneedles can be used to confirm penetration of semi‐permeable membranes such as the round window membrane (RWM) by detection of voltage change at the moment of perforation. Background: The introduction of microperforations in the RWM can significantly enhance intracochlear delivery of therapeutics. However, the moment of needle penetration through the RWM cannot be reliably detected by visualization or sensation alone. We explore the ability of electrochemical detection of penetration in defining the precise instant a microneedle enters the inner ear. Methods: 0.2 mm diameter stainless steel Minutien pins were electroplated with copper, then silver. Pins were then soaked in bleach for 24 h to complete Ag/AgCl plating. Experiments were performed using a 3 mL Franz cell diffusion system with 1%, 2%, 3%, 4%, and 5% saline solution in the donor chamber and artificial perilymph solution in the receptor chamber separated by 5‐μm pore synthetic membrane. Continuous voltage measurements were made throughout the process of membrane penetration by the microneedle ( N = 6 for each saline concentration). Results: Silver‐plated needles were able to detect an instantaneous change in voltage when traversing the membrane from saline solution into artificial perilymph. As calculated, the magnitude of the change in voltage upon penetration increased with increasing saline concentration and was stable across trials. Conclusion: Ag/AgCl coated microneedles are effective in detecting the moment of penetration across semi‐permeable membranes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 307–311, 2017.