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Zhou C, Aksit A, Szeto B, Li RL, Lalwani AK, Kysar JW. Pyrolyzed Ultrasharp Glassy Carbon Microneedles. ADVANCED ENGINEERING MATERIALS 2022; 24:2270046. [PMID: 36686328 PMCID: PMC9858104 DOI: 10.1002/adem.202270046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Polymeric microneedles fabricated via two-photon polymerization (2PP) lithography enable safe medical access to the inner ear. Herein, the material class for 2PP-lithography-based microneedles is expanded by pyrolyzing 2PP-fabricated polymeric microneedles, resulting in glassy carbon microneedles. During pyrolysis the microneedles shrink up to 81% while maintaining their complex shape when the exposed surface-area-to-volume ratio (SVR) is 0.025 < SVR < 0.04, for the temperature history protocol used herein. The derived glassy carbon is confirmed with energy-dispersive X-ray spectroscopy and Raman spectroscopy. The pyrolyzed glassy carbon has Young's modulus 9.0 GPa. As a brittle material, the strength is stochastic. Using the two-parameter Weibull distribution, the glassy carbon has Weibull modulus of 3.1 and characteristic strength of 710 MPa. The viscoelastic response has characteristic time scale of about 10000 s. In vitro experiments demonstrate that the glassy carbon microneedles introduce controlled perforations across the guinea pig round window membrane (RWM) from the middle ear space into the inner ear, without damaging the microneedle. The resultant controlled perforation of RWM is known to enhance diffusion of therapeutics across the RWM in a predictable fashion. Hence, the glassy carbon microneedles can be deployed for mediating inner ear delivery.
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Affiliation(s)
- Chaoqun Zhou
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - Aykut Aksit
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - Betsy Szeto
- Department of Otolaryngology - Head & Neck Surgery, Columbia University, New York, NY 10032, USA
| | - Richard L Li
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
| | - Anil K Lalwani
- Department of Otolaryngology - Head & Neck Surgery, Columbia University, New York, NY 10032, USA
| | - Jeffrey W Kysar
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA; Department of Otolaryngology - Head & Neck Surgery, Columbia University, New York, NY 10032, USA
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Szeto B, Valentini C, Aksit A, Werth EG, Goeta S, Brown LM, Olson ES, Kysar JW, Lalwani AK. Impact of Systemic versus Intratympanic Dexamethasone Administration on the Perilymph Proteome. J Proteome Res 2021; 20:4001-4009. [PMID: 34291951 DOI: 10.1021/acs.jproteome.1c00322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glucocorticoids are the first-line treatment for sensorineural hearing loss, but little is known about the mechanism of their protective effect or the impact of route of administration. The recent development of hollow microneedles enables safe and reliable sampling of perilymph for proteomic analysis. Using these microneedles, we investigate the effect of intratympanic (IT) versus intraperitoneal (IP) dexamethasone administration on guinea pig perilymph proteome. Guinea pigs were treated with IT dexamethasone (n = 6), IP dexamethasone (n = 8), or untreated for control (n = 8) 6 h prior to aspiration. The round window membrane (RWM) was accessed via a postauricular approach, and hollow microneedles were used to perforate the RWM and aspirate 1 μL of perilymph. Perilymph samples were analyzed by liquid chromatography-mass spectrometry-based label-free quantitative proteomics. Mass spectrometry raw data files have been deposited in an international public repository (MassIVE proteomics repository at https://massive.ucsd.edu/) under data set # MSV000086887. In the 22 samples of perilymph analyzed, 632 proteins were detected, including the inner ear protein cochlin, a perilymph marker. Of these, 14 proteins were modulated by IP, and three proteins were modulated by IT dexamethasone. In both IP and IT dexamethasone groups, VGF nerve growth factor inducible was significantly upregulated compared to control. The remaining adjusted proteins modulate neurons, inflammation, or protein synthesis. Proteome analysis facilitated by the use of hollow microneedles shows that route of dexamethasone administration impacts changes seen in perilymph proteome. Compared to IT administration, the IP route was associated with greater changes in protein expression, including proteins involved in neuroprotection, inflammatory pathway, and protein synthesis. Our findings show that microneedles can mediate safe and effective intracochlear sampling and hold promise for inner ear diagnostics.
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Affiliation(s)
- Betsy Szeto
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Vagelos College of Physicians and Surgeons, New York, New York 10032, United States
| | - Chris Valentini
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Vagelos College of Physicians and Surgeons, New York, New York 10032, United States
| | - Aykut Aksit
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Emily G Werth
- Quantitative Proteomics and Metabolomics Center, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Shahar Goeta
- Quantitative Proteomics and Metabolomics Center, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Lewis M Brown
- Quantitative Proteomics and Metabolomics Center, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Elizabeth S Olson
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Vagelos College of Physicians and Surgeons, New York, New York 10032, United States.,Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
| | - Jeffrey W Kysar
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Vagelos College of Physicians and Surgeons, New York, New York 10032, United States.,Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Anil K Lalwani
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Vagelos College of Physicians and Surgeons, New York, New York 10032, United States.,Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
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