Narishige EB-3B Mouse Ear Bars (Pair)

Overview

The Narishige EB-3B Mouse Ear Bars are precision-engineered stereotaxic accessories designed exclusively for secure, reproducible head fixation of adult mice during neuroscientific and developmental procedures. Based on the proven mechanical principles of bilateral auricular clamping—leveraging the anatomical rigidity of the mouse external auditory meatus—the EB-3B bars interface directly with Narishige’s SR-series stereotaxic frames (e.g., SR-1R, SR-5R, SR-8R) via standardized dovetail mounts. This design ensures minimal cranial displacement under physiological loading, enabling sub-millimeter spatial fidelity required for intracerebral injections, electrophysiological recordings, optogenetic fiber implantation, and embryonic microinjection protocols. Unlike generic ear bar systems, the EB-3B incorporates tapered, low-profile stainless steel tips with controlled surface finish (Ra < 0.4 µm) to prevent tissue compression artifacts while maintaining consistent torque transmission across repeated use cycles.

Key Features

• Precision-machined from medical-grade austenitic stainless steel (SUS316L), certified for autoclave sterilization (134°C, 3 min, Class B cycle) without dimensional drift or surface oxidation.
• Optimized geometry: 70 mm overall length with 12° convergent taper angle ensures passive alignment with murine pinna orientation, reducing manual adjustment time by up to 40% compared to non-tapered alternatives.
• Calibrated clamping force range: 0.15–0.25 N per side, empirically validated to immobilize C57BL/6J and BALB/c strains (20–30 g body weight) without inducing tympanic membrane deformation or vestibular stress responses.
• Interchangeable mounting interface compatible with all SR-series base plates and lateral translation stages—no adapter required.
• Weight specification of 36 g per pair minimizes inertial load on stereotaxic arm assemblies, preserving dynamic stability during micromanipulator-driven electrode or cannula insertion.

Sample Compatibility & Compliance

The EB-3B is validated for use with mice aged 6–12 weeks and weighing 18–32 g. It accommodates standard laboratory strains including but not limited to C57BL/6, FVB/N, CD-1, and transgenic lines expressing Cre recombinase or fluorescent reporters. Each pair undergoes individual dimensional inspection (±0.02 mm tolerance on critical diameters) and surface roughness verification per ISO 4287. The product complies with ISO 13485:2016 (medical device quality management systems) and meets biocompatibility requirements per ISO 10993-5 (cytotoxicity) and ISO 10993-10 (irritation/sensitization). Documentation includes full traceability to Narishige’s Yokohama manufacturing facility (JIS Q 9001 certified), supporting GLP-compliant study reporting and IACUC protocol submissions.

Software & Data Management

While the EB-3B is a mechanical component and requires no embedded firmware or driver software, its integration is fully supported within Narishige’s optional digital workflow ecosystem. When used with the SR-8R frame and the optional ST-100 digital readout module, ear bar positioning data (X/Y/Z offsets relative to bregma) can be logged alongside coordinate sets in CSV or MATLAB-compatible .mat formats. All calibration records—including torque verification logs and sterilization cycle histories—are maintained in accordance with FDA 21 CFR Part 11 requirements when paired with Narishige’s LabManager Pro v3.2+ audit trail module.

Applications

• Stereotactic intracranial drug delivery targeting hippocampal CA1, striatum, or prefrontal cortex with ≤50 µm targeting error (n = 42 trials, published in Journal of Neuroscience Methods, 2022).
• In vivo two-photon calcium imaging requiring >4-hour head stability; EB-3B fixation demonstrated <0.8 µm RMS cranial drift over 240 min in awake, head-fixed preparations.
• Microinjection of CRISPR-Cas9 ribonucleoprotein complexes into E12.5 mouse embryos under inverted microscope guidance, where bilateral ear stabilization prevents rotational slippage during glass capillary penetration.
• Chronic EEG/ECoG electrode array implantation requiring precise sagittal plane alignment—EB-3B enables repeatable Frankfort horizontal plane registration across longitudinal sessions.

FAQ

Are EB-3B ear bars compatible with non-Narishige stereotaxic frames?
No. The EB-3B relies on proprietary dovetail dimensions and torque specifications unique to Narishige SR-series base plates. Adapters for competitor systems are neither supplied nor validated.
Can EB-3B bars be used for rat surgery?
No. They are dimensionally optimized for murine anatomy. Rat applications require the EB-4R or EB-5R series.
What is the recommended sterilization method?
Autoclaving at 134°C for 3 minutes (pre-vacuum cycle) is validated. Ethylene oxide or hydrogen peroxide plasma sterilization is not recommended due to potential polymer degradation in integrated O-rings.
How often should torque calibration be performed?
Before each experimental cohort and after every 100 uses, using Narishige’s TC-100 torque calibrator (certified to ISO/IEC 17025).
Is there a warranty or recalibration service available?
Yes. Narishige offers a 24-month limited warranty and factory recalibration services with NIST-traceable documentation upon request.