Magnetoactive elastomer as an element of a magnetic retina fixator

Abstract

We explore the possibility of creating an effective retinal fixator on the basis of magnetoactive elastomers (MAEs) and systems of permanent magnets. MAEs consist of silicone elastomer matrix with embedded magnetic iron microparticles. We study theoretically and experimentally magnetic forces acting between MAE samples and permanent magnets in various configurations. The theoretical model is based around classical magnetostatics and Maxwell equations with different parameters accounting for peculiarities of the material and the setup. Approximation of the experimentally measured magnetization curves for MAE samples was used to find input parameters for the theoretical model. To test the model, we conducted a series of experimental measurements of magnetic forces accompanied by model predictions for the system of one cylindrical magnet and a cuboid MAE sample. Calculated dependences of the average pressure arising from magnetic interactions on the distance between the closest faces of MAE samples and a permanent magnet are in a good agreement with the experimental data. The proof on concept for smaller magnetic systems required for eye surgery includes data for 10 magnets configuration and a thin MAE band. This research demonstrates high prospects of using MAE as an element of a magnetic fixator for treatment of complicated retinal detachments.

Influence of the geometry on magnetic interactions in a retina fixator based on a magnetoactive elastomer seal

“…The magnetic buckle consisting of several magnets covered by medical silicone rubber is sutured to the sclera, and a MAE seal is introduced into the eye through a small incision and placed on the retina surface. This paper continues and improves upon our previous combined theoretical and experimental study demonstrating high prospects of using an MAE as an element of a magnetic fixator for treatment of complicated retinal detachments [17]. Our previous work involved setting up the model and checking its validity through calculation of the interaction parameters for test flat configurations as well as comparison with experimental data [17].…”

“…This paper continues and improves upon our previous combined theoretical and experimental study demonstrating high prospects of using an MAE as an element of a magnetic fixator for treatment of complicated retinal detachments [17]. Our previous work involved setting up the model and checking its validity through calculation of the interaction parameters for test flat configurations as well as comparison with experimental data [17]. Here we are exploring how varying the geometric configuration of the system affects the results.…”

“…As for the MAE seal, we perform calculations for the sample containing 75mass % of iron particles. MAEs of this composition were used in our previous publication [17] in order to test the theoretical model. The MAE sample is cuboid-shaped and it either covers the entire upper side of the magnetic buckle or has the size equal to two periods of it.…”

“…The comparison of the modeling results with the experimental data was performed in our previous work [17]. It has shown that two factors need to be considered when modeling the interaction between a MAE sample and a system of magnets.…”

“…For the field dependence itself we use the Langevin model and do not introduce magnetic hysteresis into our model, since the experimental results for our samples showed hysteresis to be insignificant. Our previous work contains a more detailed explanation of the modeling process with both factors taken into account as well as information about experimental support as it outlines the basis of this particular research [17]. Experimental data for cylindrical neodymium magnets (R = 2 mm and hm = 1 mm) as well as MAE samples with 75 mass percentage of magnetic filler obtained in [17] was used to derive the necessary uniqueness conditions for the magnetization distribution and to calculate the parameters of the Langevin model respectively.…”