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  1. Article ; Online: Microneedles Facilitate Small-Volume Intracochlear Delivery Without Physiologic Injury in Guinea Pigs.

    Leong, Stephen / Feng, Sharon J / Aksit, Aykut / Olson, Elizabeth S / Kysar, Jeffrey W / Lalwani, Anil K

    Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology

    2023  Volume 44, Issue 5, Page(s) 513–519

    Abstract: Hypothesis: Microneedle-mediated intracochlear injection through the round window membrane (RWM) will facilitate intracochlear delivery, not affect hearing, and allow for full reconstitution of the RWM within 48 hours.: Background: We have developed ... ...

    Abstract Hypothesis: Microneedle-mediated intracochlear injection through the round window membrane (RWM) will facilitate intracochlear delivery, not affect hearing, and allow for full reconstitution of the RWM within 48 hours.
    Background: We have developed polymeric microneedles that allow for in vivo perforation of the guinea pig RWM and aspiration of perilymph for diagnostic analysis, with full reconstitution of the RWM within 48 to 72 hours. In this study, we investigate the ability of microneedles to deliver precise volumes of therapeutics into the cochlea and assess the subsequent consequences on hearing.
    Methods: Volumes of 1.0, 2.5, or 5.0 μL of artificial perilymph were injected into the cochlea at a rate of 1 μL/min. Compound action potential (CAP) and distortion product otoacoustic emission were performed to assess for hearing loss (HL), and confocal microscopy was used to evaluate the RWM for residual scarring or inflammation. To evaluate the distribution of agents within the cochlea after microneedle-mediated injection, 1.0 μL of FM 1-43 FX was injected into the cochlea, followed by whole mount cochlear dissection and confocal microscopy.
    Results: Direct intracochlear injection of 1.0 μL of artificial perilymph in vivo , corresponding to about 20% of the scala tympani volume, was safe and did not result in HL. However, injection of 2.5 or 5.0 μL of artificial perilymph into the cochlea produced statistically significant high-frequency HL persisting 48 hours postperforation. Assessment of RWMs 48 hours after perforation revealed no inflammatory changes or residual scarring. FM 1-43 FX injection resulted in distribution of the agent predominantly in the basal and middle turns.
    Conclusion: Microneedle-mediated intracochlear delivery of small volumes relative to the volume of the scala tympani is feasible, safe, and does not cause HL in guinea pigs; however, injection of large volumes induces high-frequency HL. Injection of small volumes of a fluorescent agent across the RWM resulted in significant distribution within the basal turn, less distribution in the middle turn, and almost none in the apical turn. Microneedle-mediated intracochlear injection, along with our previously developed intracochlear aspiration, opens the pathway for precision inner ear medicine.
    MeSH term(s) Guinea Pigs ; Animals ; Cicatrix ; Cochlea/metabolism ; Scala Tympani ; Pyridinium Compounds/metabolism ; Round Window, Ear ; Perilymph/metabolism
    Chemical Substances FM1 43 ; Pyridinium Compounds
    Language English
    Publishing date 2023-04-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2036790-9
    ISSN 1537-4505 ; 1531-7129
    ISSN (online) 1537-4505
    ISSN 1531-7129
    DOI 10.1097/MAO.0000000000003845
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Simulation assisted design for microneedle manufacturing: Computational modeling of two-photon templated electrodeposition.

    Aksit, Aykut / Lalwani, Anil K / Kysar, Jeffrey W / West, Alan C

    Journal of manufacturing processes

    2021  Volume 66, Page(s) 211–219

    Abstract: Fully metallic micrometer-scale 3D architectures can be fabricated via a hybrid additive methodology combining multi-photon lithography with electrochemical deposition of metals. The methodology - referred to as two-photon templated electrodeposition ( ... ...

    Abstract Fully metallic micrometer-scale 3D architectures can be fabricated via a hybrid additive methodology combining multi-photon lithography with electrochemical deposition of metals. The methodology - referred to as two-photon templated electrodeposition (2PTE) - has significant design freedom that enables the creation of complicated, traditionally difficult-to-make, high aspect ratio metallic structures such as microneedles. These complicated geometries, combined with their fully metallic nature, can enable precision surgical applications such as inner ear drug delivery or fluid sampling. However, the process involves electrochemical deposition of metals into complicated 3D lithography patterns thicker than 500 μm. This causes potential and chemical gradients to develop within the 3D template, creating limitations to what can be designed. These limitations can be explored, understood, and overcome via numerical modeling. Herein we introduce a numerical model as a design tool that can predict growth for manufacturing complicated 3D metallic geometries. The model is successful in predicting the geometric result of 2PTE, and enables extraction of insights about geometric constraints through exploration of its mechanics.
    Language English
    Publishing date 2021-04-16
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2168529-0
    ISSN 1526-6125 ; 0278-6125
    ISSN 1526-6125 ; 0278-6125
    DOI 10.1016/j.jmapro.2021.04.023
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Inner Ear Diagnostics and Drug Delivery via Microneedles.

    Leong, Stephen / Aksit, Aykut / Feng, Sharon J / Kysar, Jeffrey W / Lalwani, Anil K

    Journal of clinical medicine

    2022  Volume 11, Issue 18

    Abstract: Objectives: Precision medicine for inner ear disorders has seen significant advances in recent years. However, unreliable access to the inner ear has impeded diagnostics and therapeutic delivery. The purpose of this review is to describe the development, ...

    Abstract Objectives: Precision medicine for inner ear disorders has seen significant advances in recent years. However, unreliable access to the inner ear has impeded diagnostics and therapeutic delivery. The purpose of this review is to describe the development, production, and utility of novel microneedles for intracochlear access.
    Methods: We summarize the current work on microneedles developed using two-photon polymerization (2PP) lithography for perforation of the round window membrane (RWM). We contextualize our findings with the existing literature in intracochlear diagnostics and delivery.
    Results: Two-photon polymerization lithography produces microneedles capable of perforating human and guinea pig RWMs without structural or functional damage. Solid microneedles may be used to perforate guinea pig RWMs in vivo with full reconstitution of the membrane in 48-72 h, and hollow microneedles may be used to aspirate perilymph or inject therapeutics into the inner ear. Microneedles produced with two-photon templated electrodeposition (2PTE) have greater strength and biocompatibility and may be used to perforate human RWMs.
    Conclusions: Microneedles produced with 2PP lithography and 2PTE can safely and reliably perforate the RWM for intracochlear access. This technology is groundbreaking and enabling in the field of inner ear precision medicine.
    Language English
    Publishing date 2022-09-17
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2662592-1
    ISSN 2077-0383
    ISSN 2077-0383
    DOI 10.3390/jcm11185474
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Pyrolyzed Ultrasharp Glassy Carbon Microneedles.

    Zhou, Chaoqun / Aksit, Aykut / Szeto, Betsy / Li, Richard L / Lalwani, Anil K / Kysar, Jeffrey W

    Advanced engineering materials

    2022  Volume 24, Issue 11

    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 ... ...

    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.
    Language English
    Publishing date 2022-11-16
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2016980-2
    ISSN 1527-2648 ; 1438-1656
    ISSN (online) 1527-2648
    ISSN 1438-1656
    DOI 10.1002/adem.202270046
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Physiologic Effects of Microneedle-Mediated Intracochlear Dexamethasone Injection in the Guinea Pig.

    Feng, Sharon J / Leong, Stephen / Aksit, Aykut / Hébert, Daniella / Olson, Elizabeth S / Kysar, Jeffrey W / Lalwani, Anil K

    The Laryngoscope

    2023  Volume 134, Issue 1, Page(s) 388–392

    Abstract: Objectives: Oral or intratympanic corticosteroids are commonly used to treat sudden sensorineural hearing loss (SSHL), tinnitus, and Meniere disease. Direct intracochlear delivery has been proposed to overcome the variability in bioavailability and ... ...

    Abstract Objectives: Oral or intratympanic corticosteroids are commonly used to treat sudden sensorineural hearing loss (SSHL), tinnitus, and Meniere disease. Direct intracochlear delivery has been proposed to overcome the variability in bioavailability and efficacy of systemic or middle ear delivery. In this study, we aim to characterize the physiologic consequences of microneedle-mediated direct intracochlear injection of dexamethasone through the round window membrane (RWM).
    Methods: In Hartley guinea pigs (n = 5), a post-auricular incision followed by bullostomy was made to access the round window membrane. Using 100 μm diameter hollow microneedles, 1.0 μl of 10 mg/ml dexamethasone was injected through the RWM over 1 min. Compound action potential (CAP) and distortion product otoacoustic action emissions (DPOAE) were measured before perforation, at 1 h, and at 5 h following injection. CAP hearing thresholds were measured from 0.5 to 40 kHz, and DPOAE f2 frequencies ranged from 1.0 and 32 kHz. Repeated measures ANOVA followed by pairwise t-tests were used for statistical analysis.
    Results: ANOVA identified significant CAP threshold shifts at four frequencies (4, 16, 36, and 40 kHz) and differences in DPOAE at 1 frequency (6 kHz). Paired t-tests revealed differences between the pre-perforation and 1 h time point. By 5 h post injection, both CAP hearing thresholds and DPOAE recover and are not significantly different from baseline thresholds.
    Conclusion: Direct intracochlear delivery of dexamethasone via microneedles results in temporary shifts in hearing thresholds that resolve by 5 hours, thus supporting microneedle technology for the treatment of inner ear disorders.
    Level of evidence: NA Laryngoscope, 134:388-392, 2024.
    MeSH term(s) Guinea Pigs ; Animals ; Hearing ; Hearing Loss, Sensorineural ; Tinnitus ; Meniere Disease ; Dexamethasone
    Chemical Substances Dexamethasone (7S5I7G3JQL)
    Language English
    Publishing date 2023-06-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 80180-x
    ISSN 1531-4995 ; 0023-852X
    ISSN (online) 1531-4995
    ISSN 0023-852X
    DOI 10.1002/lary.30811
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Anatomic, physiologic, and proteomic consequences of repeated microneedle-mediated perforations of the round window membrane.

    Leong, Stephen / Aksit, Aykut / Szeto, Betsy / Feng, Sharon J / Ji, Xiang / Soni, Rajesh K / Olson, Elizabeth S / Kysar, Jeffrey W / Lalwani, Anil K

    Hearing research

    2023  Volume 432, Page(s) 108739

    Abstract: Background: We have developed 3D-printed microneedle technology for diagnostic aspiration of perilymph and intracochlear delivery of therapeutic agents. Single microneedle-mediated round window membrane (RWM) perforation does not cause hearing loss, ... ...

    Abstract Background: We have developed 3D-printed microneedle technology for diagnostic aspiration of perilymph and intracochlear delivery of therapeutic agents. Single microneedle-mediated round window membrane (RWM) perforation does not cause hearing loss, heals within 48-72 h, and yields sufficient perilymph for proteomic analysis. In this study, we investigate the anatomic, physiologic, and proteomic consequences of repeated microneedle-mediated perforations of the same RWM at different timepoints.
    Methods: 100-μm-diameter hollow microneedles were fabricated using two-photon polymerization (2PP) lithography. The tympanic bullae of Hartley guinea pigs (n = 8) were opened with adequate exposure of the RWM. Distortion product otoacoustic emissions (DPOAE) and compound action potential (CAP) were recorded to assess hearing. The hollow microneedle was introduced into the bulla and the RWM was perforated; 1 μL of perilymph was aspirated from the cochlea over the course of 45 s. 72 h later, the above procedure was repeated with aspiration of an additional 1 μL of perilymph. 72 h after the second perforation, RWMs were harvested for confocal imaging. Perilymph proteomic analysis was completed using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
    Results: Two perforations and aspirations were performed in 8 guinea pigs. In six, CAP, DPOAE, and proteomic analysis were obtained; in one, only CAP and DPOAE results were obtained; and in one, only proteomics results were obtained. Hearing tests demonstrated mild hearing loss at 1-4 kHz and 28 kHz, most consistent with conductive hearing loss. Confocal microscopy demonstrated complete healing of all perforations with full reconstitution of the RWM. Perilymph proteomic analysis identified 1855 proteins across 14 samples. The inner ear protein cochlin was observed in all samples, indicating successful aspiration of perilymph. Non-adjusted paired t-tests with p < 0.01 revealed significant changes in 13 of 1855 identified proteins (0.7%) between the first and second aspirations.
    Conclusions: We demonstrate that repeated microneedle perforation of the RWM is feasible, allows for complete healing of the RWM, and minimally changes the proteomic expression profile. Thus, microneedle-mediated repeated aspirations in a single animal can be used to monitor the response to inner ear treatments over time.
    MeSH term(s) Animals ; Guinea Pigs ; Chromatography, Liquid ; Proteomics ; Tandem Mass Spectrometry ; Round Window, Ear/metabolism ; Cochlea/metabolism ; Perilymph/metabolism ; Hearing Loss/metabolism
    Language English
    Publishing date 2023-03-14
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 282629-x
    ISSN 1878-5891 ; 0378-5955
    ISSN (online) 1878-5891
    ISSN 0378-5955
    DOI 10.1016/j.heares.2023.108739
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Impact of Systemic versus Intratympanic Dexamethasone Administration on the Perilymph Proteome

    Szeto, Betsy / Valentini, Chris / Aksit, Aykut / Werth, Emily G. / Goeta, Shahar / Brown, Lewis M. / Olson, Elizabeth S. / Kysar, Jeffrey W. / Lalwani, Anil K.

    Journal of proteome research. 2021 July 22, v. 20, no. 8

    2021  

    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 ... ...

    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.
    Keywords data collection ; dexamethasone ; diagnostic techniques ; glucocorticoids ; guinea pigs ; inflammation ; inner ear ; liquid chromatography ; mass spectrometry ; nerve growth factor ; neuroprotective effect ; protein synthesis ; proteome ; proteomics ; research ; Guinea
    Language English
    Dates of publication 2021-0722
    Size p. 4001-4009.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 2078618-9
    ISSN 1535-3907 ; 1535-3893
    ISSN (online) 1535-3907
    ISSN 1535-3893
    DOI 10.1021/acs.jproteome.1c00322
    Database NAL-Catalogue (AGRICOLA)

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  8. Article ; Online: Drug delivery device for the inner ear: ultra-sharp fully metallic microneedles.

    Aksit, Aykut / Rastogi, Shruti / Nadal, Maria L / Parker, Amber M / Lalwani, Anil K / West, Alan C / Kysar, Jeffrey W

    Drug delivery and translational research

    2020  Volume 11, Issue 1, Page(s) 214–226

    Abstract: Drug delivery into the inner ear is a significant challenge due to its inaccessibility as a fluid-filled cavity within the temporal bone of the skull. The round window membrane (RWM) is the only delivery portal from the middle ear to the inner ear that ... ...

    Abstract Drug delivery into the inner ear is a significant challenge due to its inaccessibility as a fluid-filled cavity within the temporal bone of the skull. The round window membrane (RWM) is the only delivery portal from the middle ear to the inner ear that does not require perforation of bone. Recent advances in microneedle fabrication enable the RWM to be perforated safely with polymeric microneedles as a means to enhance the rate of drug delivery from the middle ear to the inner ear. However, the polymeric material is not biocompatible and also lacks the strength of other materials. Herein we describe the design and development of gold-coated metallic microneedles suitable for RWM perforation. When developing microneedle technology for drug delivery, we considered three important general attributes: (1) high strength and ductility material, (2) high accuracy and precision of fabrication, and (3) broad design freedom. We developed a hybrid additive manufacturing method using two-photon lithography and electrochemical deposition to fabricate ultra-sharp gold-coated copper microneedles with these attributes. We refer to the microneedle fabrication methodology as two-photon templated electrodeposition (2PTE). We demonstrate the use of these microneedles by inducing a perforation with a minimal degree of trauma in a guinea pig RWM while the microneedle itself remains undamaged. Thus, this microneedle has the potential literally of opening the RWM for enhanced drug delivery into the inner ear. Finally, the 2PTE methodology can be applied to many different classes of microneedles for other drug delivery purposes as well the fabrication of small scale structures and devices for non-medical applications. Graphical Abstract Fully metallic ultra-sharp microneedle mounted at end of a 24-gauge stainless steel blunt syringe needle tip: (left) Size of microneedle shown relative to date stamp on U.S. one-cent coin; (right) Perforation through guinea pig round window membrane introduced with microneedle.
    MeSH term(s) Animals ; Drug Delivery Systems ; Ear, Inner ; Guinea Pigs ; Needles ; Pharmaceutical Preparations ; Round Window, Ear
    Chemical Substances Pharmaceutical Preparations
    Language English
    Publishing date 2020-06-05
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2590155-2
    ISSN 2190-3948 ; 2190-393X
    ISSN (online) 2190-3948
    ISSN 2190-393X
    DOI 10.1007/s13346-020-00782-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Impact of Systemic versus Intratympanic Dexamethasone Administration on the Perilymph Proteome.

    Szeto, Betsy / Valentini, Chris / Aksit, Aykut / Werth, Emily G / Goeta, Shahar / Brown, Lewis M / Olson, Elizabeth S / Kysar, Jeffrey W / Lalwani, Anil K

    Journal of proteome research

    2021  Volume 20, Issue 8, Page(s) 4001–4009

    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 ... ...

    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 (
    MeSH term(s) Animals ; Dexamethasone/administration & dosage ; Glucocorticoids/administration & dosage ; Guinea Pigs ; Injection, Intratympanic ; Perilymph ; Proteome ; Proteomics
    Chemical Substances Glucocorticoids ; Proteome ; Dexamethasone (7S5I7G3JQL)
    Language English
    Publishing date 2021-07-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2078618-9
    ISSN 1535-3907 ; 1535-3893
    ISSN (online) 1535-3907
    ISSN 1535-3893
    DOI 10.1021/acs.jproteome.1c00322
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: 3D-Printed Microneedles Create Precise Perforations in Human Round Window Membrane in Situ.

    Chiang, Harry / Yu, Michelle / Aksit, Aykut / Wang, Wenbin / Stern-Shavit, Sagit / Kysar, Jeffrey W / Lalwani, Anil K

    Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology

    2019  Volume 41, Issue 2, Page(s) 277–284

    Abstract: Hypothesis: Three-dimensional (3D)-printed microneedles can create precise holes on the scale of micrometers in the human round window membrane (HRWM).: Background: An intact round window membrane is a barrier to delivery of therapeutic and ... ...

    Abstract Hypothesis: Three-dimensional (3D)-printed microneedles can create precise holes on the scale of micrometers in the human round window membrane (HRWM).
    Background: An intact round window membrane is a barrier to delivery of therapeutic and diagnostic agents into the inner ear. Microperforation of the guinea pig round window membrane has been shown to overcome this barrier by enhancing diffusion 35-fold. In humans, the challenge is to design a microneedle that can precisely perforate the thicker HRWM without damage.
    Methods: Based on the thickness and mechanical properties of the HRWM, two microneedle designs were 3D-printed to perforate the HRWM from fresh frozen temporal bones in situ (n = 18 total perforations), simultaneously measuring force and displacement. Perforations were analyzed using confocal microscopy; microneedles were examined for deformity using scanning electron microscopy.
    Results: HRWM thickness was determined to be 60.1 ± 14.6 (SD) μm. Microneedles separated the collagen fibers and created slit-shaped perforations with the major axis equal to the microneedle shaft diameter. Microneedles needed to be displaced only minimally after making initial contact with the RWM to create a complete perforation, thus avoiding damage to intracochlear structures. The microneedles were durable and intact after use.
    Conclusion: 3D-printed microneedles can create precise perforations in the HRWM without damaging intracochlear structures. As such, they have many potential applications ranging from aspiration of cochlear fluids using a lumenized needle for diagnosis and creating portals for therapeutic delivery into the inner ear.
    MeSH term(s) Animals ; Cochlea ; Guinea Pigs ; Humans ; Needles ; Printing, Three-Dimensional ; Round Window, Ear/diagnostic imaging ; Round Window, Ear/surgery
    Language English
    Publishing date 2019-11-19
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2036790-9
    ISSN 1537-4505 ; 1531-7129
    ISSN (online) 1537-4505
    ISSN 1531-7129
    DOI 10.1097/MAO.0000000000002480
    Database MEDical Literature Analysis and Retrieval System OnLINE

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