Objective: A novel hearing-aid scheme using magnetomotive nanoparticles (MNPs) as transducers in the tympanic membrane (TM) is proposed, aiming to noninvasively and directly induce a modulated vibration on the TM. Methods: In this feasibility study, iron oxide (Fe3O4) nanoparticles were applied on ex vivo rat TM tissues and allowed to diffuse over ∼2 h. Subsequently, magnetic force was exerted on the MNP-laden TM via a programmable electromagnetic solenoid to induce the magnetomotion. Optical coherence tomography (OCT), along with its phase-sensitive measurement capabilities, was utilized to visualize and quantify the nanometer-scale vibrations generated on the TM tissues. Results: The magnetomotive displacements induced on the TM were significantly greater than the baseline vibration of the TM without MNPs. In addition to a pure frequency tone, a chirped excitation and the corresponding spectroscopic response were also successfully generated and obtained. Finally, visualization of volumetric TM dynamics was achieved. Conclusion: This study demonstrates the effectiveness of magnetically inducing vibrations on TMs containing iron oxide nanoparticles, manipulating the amplitude and the frequency of the induced TM motions, and the capability of assessing the magnetomotive dynamics via OCT. Significance: The results demonstrated here suggest the potential use of this noninvasive magnetomotive approach in future hearing aid applications. OCT can be utilized to investigate the magnetomotive dynamics of the TM, which may either enhance sound perception or magnetically induce the perception of sound without the need for acoustic speech signals.

Original languageEnglish (US)
Article number8325518
Pages (from-to)2837-2846
Number of pages10
JournalIEEE Transactions on Biomedical Engineering
Issue number12
StatePublished - Dec 2018


  • Magnetic nanoparticles
  • hearing aids
  • magnetomotive
  • optical coherence tomography
  • tympanic membrane

ASJC Scopus subject areas

  • Biomedical Engineering


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