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Novel 3D-printed hollow microneedles facilitate safe, reliable, and informative sampling of perilymph from guinea
Betsy Szeto1, Aykut Aksit2, Chris Valentini1
1Department of Otolaryngology - Head and Neck Surgery, Columbia University Vagelos College of Physicians and Surgeons, 180 Fort Washington Avenue, Harkness Pavilion, 8th Floor, New York, NY 10032, United States.
Background:
Inner ear diagnostics is limited by the inability to atraumatically obtain samples of inner ear fluid. The round window membrane (RWM) is an attractive portal for accessing perilymph samples as it has been shown to heal within one week after the introduction of microperforations. A 1 µL volume of perilymph is adequate for proteome analysis, yet the total volume of perilymph within the scala tympani of the guinea pig is limited to less than 5 µL. This study investigates the safety and reliability of a novel hollow microneedle device to aspirate perilymph samples adequate for proteomic analysis.
Methods:
The guinea pig RWM was accessed via a postauricular surgical approach. 3D-printed hollow microneedles with an outer diameter of 100 µm and an inner diameter of 35 µm were used to perforate the RWM and aspirate 1 µL of perilymph. Two perilymph samples were analyzed by liquid chromatography-mass spectrometry-based quantitative proteomics as part of a preliminary study. Hearing was assessed before and after aspiration using compound action potential (CAP) and distortion product otoacoustic emissions (DPOAE). RWMs were harvested 72 h after aspiration and evaluated for healing using confocal microscopy.
Results:
There was no permanent damage to hearing at 72 h after perforation as assessed by CAP (n = 7) and DPOAE (n = 8), and all perforations healed completely within 72 h (n = 8). In the two samples of perilymph analyzed, 620 proteins were detected, including the inner ear protein cochlin, widely recognized as a perilymph marker.
Conclusion:
Hollow microneedles can facilitate aspiration of perilymph across the RWM at a quality and volume adequate for proteomic analysis without causing permanent anatomic or physiologic dysfunction. Microneedles can mediate safe and effective intracochlear sampling and show great promise for inner ear diagnostics.
Insights
A novel hollow microneedle safely aspirates inner ear fluid (perilymph) for proteomic analysis. This atraumatic technique allows for complete round window membrane healing within 72 hours, enabling new diagnostics.
Area of Science:
- Otolaryngology
- Biomedical Engineering
- Proteomics
Background:
- Inner ear diagnostics are hindered by the difficulty of obtaining fluid samples atraumatically.
- The round window membrane (RWM) offers a potential access point for perilymph sampling due to its healing capacity.
- Limited perilymph volume necessitates efficient and reliable sampling methods.
Purpose of the Study:
- To investigate the safety and efficacy of a novel hollow microneedle device for aspirating perilymph.
- To determine if the aspirated perilymph volume is adequate for proteomic analysis.
- To assess the impact of microneedle perforation on hearing and RWM healing.
Main Methods:
- A postauricular surgical approach was used to access the guinea pig RWM.
- 3D-printed hollow microneedles (100 µm outer diameter) were employed to perforate the RWM and aspirate 1 µL of perilymph.
- Hearing function was evaluated using compound action potential (CAP) and distortion product otoacoustic emissions (DPOAE), and RWM healing was assessed via confocal microscopy.
Main Results:
- No permanent hearing damage was observed at 72 hours post-perforation, as confirmed by CAP and DPOAE.
- All RWM perforations demonstrated complete healing within 72 hours.
- Proteomic analysis of perilymph samples identified 620 proteins, including the established perilymph marker cochlin.
Conclusions:
- Hollow microneedles provide a safe and effective method for aspirating perilymph across the RWM.
- This technique yields sufficient sample quality and volume for proteomic analysis without causing lasting dysfunction.
- Microneedle-mediated intracochlear sampling holds significant promise for advancing inner ear diagnostics.
