Joseph M Wazen1, James P Stevens1, Hirobumi Watanabe1,2, Jeffrey W Kysar2, Anil K Lalwani1. 1. Department of Otolaryngology-Head and Neck Surgery, Columbia University College of Physicians and Surgeons, New York, New York. 2. Department of Mechanical Engineering, Columbia University, New York, New York.
Abstract
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.
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.
Authors: Betsy Szeto; Aykut Aksit; Chris Valentini; Michelle Yu; Emily G Werth; Shahar Goeta; Chuanning Tang; Lewis M Brown; Elizabeth S Olson; Jeffrey W Kysar; Anil K Lalwani Journal: Hear Res Date: 2020-12-02 Impact factor: 3.208
Authors: Aykut Aksit; Shruti Rastogi; Maria L Nadal; Amber M Parker; Anil K Lalwani; Alan C West; Jeffrey W Kysar Journal: Drug Deliv Transl Res Date: 2021-02 Impact factor: 4.617
Authors: Betsy Szeto; Chris Valentini; Aykut Aksit; Emily G Werth; Shahar Goeta; Lewis M Brown; Elizabeth S Olson; Jeffrey W Kysar; Anil K Lalwani Journal: J Proteome Res Date: 2021-07-22 Impact factor: 4.466