Evaluation of the corrosion of magnets in hydrocephalus shunt valve coated in epoxy resin
4 affiliations
- 1Scientific Independent Consultant Biomaterials and Medical Devices
- 2Faculty of General Health Care, Titu Maiorescu University
- 3Department of Orthodontics, University of Medicine and Pharmacy of Craiova
- 4Department of Orthopedics and Traumatology, University of Medicine and Pharmacy Craiova
Abstract
Hydrocephalus remains a complex neurosurgical pathology requiring permanent cerebrospinal fluid (CSF) shunting. This work explores the characteristics of polymer resins, intended to isolate and stabilize the micromagnets of the pressure and flow adjustment mechanism. The polymeric disc containing the micromagnets play a critical role in the functional stability and safety of programmable valves with magnetic mechanism: any failure of the coating can lead to corrosion phenomena and ion diffusion in the CSF. It has a diameter of 5.5 mm and on it are positioned 10 magnets with a diameter of 2 mm. However, corrosion phenomena and electrochemical interactions between the magnets and LCS represent a potential risk of ion release (Co, Sm, Nd, B) and toxicity in cerebrospinal fluid (CFS). The study focuses on the nature of coating resins, by several electrochemical techniques using rotating electrode, by electrochemical impedance spectroscopy (EIE). Nielsen-Tuccillo tests and cations release on encapsulated magnets. Three resins were evaluated: Stycast 1266, Stycast 1267 and Loctite medical device application (MDA). The encapsulated magnets are of CoSm5 and CoNd2 Fe14 B nature. All tests reveal an ion exchange permeability between electrolyte NaCl 9 g/l is the coated magnets after three days of immersion. All three resins shift the polarisation curves into the domain of 10−7–10–12 A/cm2 Degradations by corrosion phenomena on the surfaces of magnets were found in the Stycast 1266 by the Nielsen-Tuccillo test after 30 days of immersion. The extraction kinetic tests were carried out for 30, 60 and 90 days. The Stycast 1267 releases cobalt mainly in the first 60 days, at approximately 0.8 µg/l. The Loctite series a level of about 0.15 µg/l is observed for 60 days, then cobalt release increases to 1.2 µg/l after 90 days. The Stycast 1267 releases Neodymium up to a concentration that could reach 0.6 µg/l. The release of Neodymium from the Loctite series is at the detection limit < 0.260 mg/l after 90 days. Future generations of valves, integrating electronic sensors and wireless telemetry, will have to take these constraints into account to ensure their long-term reliability and biocompatibility.
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BibTeX
@article{reclaru2026evaluation,
title = {{Evaluation of the corrosion of magnets in hydrocephalus shunt valve coated in epoxy resin}},
author = {Lucien Reclaru and Gabriel Buciu and Stelian-Mihai-Sever Petrescu and Alexandru Florian Grecu and Ioan Dogariu},
journal = {Scientific Reports},
year = {2026},
month = aug,
doi = {10.1038/s41598-026-63319-z},
url = {https://doi.org/10.1038/s41598-026-63319-z},
note = {CC BY},
}
RIS
TY - JOUR
TI - Evaluation of the corrosion of magnets in hydrocephalus shunt valve coated in epoxy resin
AU - Lucien Reclaru
AU - Gabriel Buciu
AU - Stelian-Mihai-Sever Petrescu
AU - Alexandru Florian Grecu
AU - Ioan Dogariu
PY - 2026
DA - 2026/08/01
JO - Scientific Reports
DO - 10.1038/s41598-026-63319-z
UR - https://doi.org/10.1038/s41598-026-63319-z
AB - Hydrocephalus remains a complex neurosurgical pathology requiring permanent cerebrospinal fluid (CSF) shunting. This work explores the characteristics of polymer resins, intended to isolate and stabilize the micromagnets of the pressure and flow adjustment mechanism. The polymeric disc containing the micromagnets play a critical role in the functional stability and safety of programmable valves with magnetic mechanism: any failure of the coating can lead to corrosion phenomena and ion diffusion in the CSF. It has a diameter of 5.5 mm and on it are positioned 10 magnets with a diameter of 2 mm. However, corrosion phenomena and electrochemical interactions between the magnets and LCS represent a potential risk of ion release (Co, Sm, Nd, B) and toxicity in cerebrospinal fluid (CFS). The study focuses on the nature of coating resins, by several electrochemical techniques using rotating electrode, by electrochemical impedance spectroscopy (EIE). Nielsen-Tuccillo tests and cations release on encapsulated magnets. Three resins were evaluated: Stycast 1266, Stycast 1267 and Loctite medical device application (MDA). The encapsulated magnets are of CoSm5 and CoNd2 Fe14 B nature. All tests reveal an ion exchange permeability between electrolyte NaCl 9 g/l is the coated magnets after three days of immersion. All three resins shift the polarisation curves into the domain of 10−7–10–12 A/cm2 Degradations by corrosion phenomena on the surfaces of magnets were found in the Stycast 1266 by the Nielsen-Tuccillo test after 30 days of immersion. The extraction kinetic tests were carried out for 30, 60 and 90 days. The Stycast 1267 releases cobalt mainly in the first 60 days, at approximately 0.8 µg/l. The Loctite series a level of about 0.15 µg/l is observed for 60 days, then cobalt release increases to 1.2 µg/l after 90 days. The Stycast 1267 releases Neodymium up to a concentration that could reach 0.6 µg/l. The release of Neodymium from the Loctite series is at the detection limit < 0.260 mg/l after 90 days. Future generations of valves, integrating electronic sensors and wireless telemetry, will have to take these constraints into account to ensure their long-term reliability and biocompatibility.
SN - 2045-2322
ER -