Berthold Mithras² LB 943 Multimode Microplate Reader

Overview

The Berthold Mithras² LB 943 is a high-performance multimode microplate reader engineered for precision, flexibility, and reproducibility in life science laboratories. Based on a modular optical architecture integrating dual-grating monochromators, low-noise photomultiplier tubes (PMTs), and configurable excitation sources—including halogen, xenon flash, and optional laser—it supports quantitative detection across absorbance, luminescence, fluorescence, time-resolved fluorescence (TRF), fluorescence polarization (FP), Förster resonance energy transfer (FRET), bioluminescence resonance energy transfer (BRET1/BRET2), homogenous time-resolved fluorescence (HTRF®), AlphaScreen®/AlphaLISA®, and chemiluminescence. Its measurement principles adhere to standardized photometric and photon-counting methodologies compliant with ISO 15197, CLSI EP10, and ASTM E2579 for assay validation. Designed for non-radioactive academic and pharmaceutical research environments, the LB 943 delivers trace-level sensitivity without compromising dynamic range (>6 decades) or inter-assay robustness—critical for longitudinal studies in cell signaling, receptor pharmacology, and biomarker quantification.

Key Features

• Triple low-noise PMTs optimized for distinct modalities: two spectrally extended PMTs (up to 850 nm) for absorbance and general fluorescence; one ultra-low-noise PMT positioned at high-sensitivity focal point for luminescence, BRET, and Alpha assays.
• Dual independent monochromators—separate excitation and emission gratings—with continuously adjustable bandwidth (4–22 nm, 1 nm increments) and optical blocking >10⁶, enabling precise spectral resolution for multiplexed and pH-sensitive fluorophore characterization.
• Hybrid filter/grating detection architecture: High-transmission interference filters (up to 25× more efficient than gratings) support rapid-ratio FP and HTRF® measurements; software-controlled filter wheel with RFID-encoded identification ensures automatic validation of center wavelength, bandwidth, and transmission profile upon insertion.
• Simultaneous top- and bottom-reading capability across all detection modes, essential for adherent-cell assays, 3D spheroid imaging, and turbid or colored media applications where signal attenuation necessitates alternative optical paths.
• Up to four programmable syringe-based injectors (10–100 µL, 1 µL increment), fully synchronized with kinetic read cycles and compatible with both top- and bottom-read configurations for 96- and 384-well formats.
• Integrated temperature control (ambient +5 °C to 45 °C, optional) with PID-regulated chamber and real-time monitoring—validated per ISO/IEC 17025 for thermal stability during long-term kinetic experiments.

Sample Compatibility & Compliance

The Mithras² LB 943 accommodates standard microplate formats from 6- to 1536-well, including opaque, clear, black, white, and UV-transparent plates, as well as specialized vessels such as Petri dishes and Terasaki plates. Its optical design minimizes well-to-well crosstalk (<5×10⁻⁶), ensuring fidelity in high-density screening. The system complies with CE, UL, and CSA safety standards and meets electromagnetic compatibility (EMC) requirements per IEC 61326-1. For regulated environments, the instrument supports audit-trail-enabled software (optional Berthold MikroWin™ with 21 CFR Part 11 compliance package), including electronic signatures, user access controls, and immutable data logging aligned with GLP and GMP documentation practices.

Software & Data Management

Controlled via MikroWin™ software (Windows-based), the LB 943 offers intuitive protocol building, real-time kinetic visualization, and automated curve fitting (linear, sigmoidal, log-log, four-parameter logistic). Raw data export is supported in CSV, XML, and Excel-compatible formats; integration with LIMS and ELN systems is achieved through ODBC and RESTful API interfaces. Spectral scanning data are processed using proprietary deconvolution algorithms to resolve overlapping emission peaks. All instrument settings—including grating positions, PMT voltage, gain, and injector timing—are stored with each dataset, satisfying traceability requirements under ISO/IEC 17025 and FDA guidance on analytical instrument qualification.

Applications

The LB 943 is routinely deployed in reporter gene assays (luciferase, GFP), caspase- and kinase-activity profiling, GPCR functional screening (cAMP, IP1, calcium flux via Fura-2 ratiometric detection), nucleic acid and protein quantification (dsDNA, BCA, Bradford), cytotoxicity/viability assessment (ATP, resazurin), binding kinetics (SPR surrogate assays), and proximity-based immunoassays (HTRF®, AlphaScreen®). Its validated performance in TRF and HTRF® makes it suitable for high-stringency biomarker validation in preclinical development, while its low-background luminescence detection enables single-cell-equivalent sensitivity in primary neuron or stem-cell-derived assay models.

FAQ

Does the Mithras² LB 943 support 21 CFR Part 11 compliance?
Yes—when configured with MikroWin™ 21 CFR Part 11 Edition, it provides electronic signatures, role-based access control, audit trails, and data integrity safeguards required for FDA-regulated workflows.
Can the instrument perform simultaneous dual-emission ratiometric measurements?
Yes—via rapid sequential filter switching (RFID-validated) or dual-monochromator acquisition, enabling Fura-2 Ca²⁺, BCECF pH, or CyQUANT/NuPAGE ratio assays with sub-second temporal resolution.
Is bottom-reading available for luminescence mode?
Yes—both top- and bottom-reading are fully supported for all detection modalities, including glow-type luminescence, with optimized optics and background subtraction algorithms.
What is the maximum plate format supported for kinetic assays with onboard injectors?
All injector-assisted kinetic protocols are validated for 96- and 384-well plates; injection synchronization is maintained across full-plate and well-scanning read modes.
How is wavelength calibration maintained over time?
The system performs automatic self-calibration using internal holmium oxide and didymium reference filters at startup and after major environmental shifts, traceable to NIST standards.