METTLER TOLEDO InPro8100 Online Optical Density Sensor for Cell Density and Biomass Monitoring
| Brand | METTLER TOLEDO |
|---|---|
| Origin | Switzerland |
| Product Line | InPro8100 Series |
| Application Domain | Bioprocess Monitoring (Microbial Fermentation & Mammalian Cell Culture) |
| Compliance | Designed for GMP/ISO 13485-aligned biomanufacturing environments |
| Installation Options | Tank-mounted, inline pipe flow cell, submersible probe |
| Measurement Principle | Near-infrared (NIR) optical absorbance at 850 nm |
| Output Signal | 4–20 mA, HART, or digital Modbus RTU/TCP |
Overview
The METTLER TOLEDO InPro8100 Online Optical Density (OD) Sensor is an industrial-grade, non-invasive process analytical technology (PAT) instrument engineered for real-time, in-situ monitoring of microbial biomass concentration and mammalian cell density during upstream bioprocessing. Unlike traditional offline sampling methods—such as spectrophotometric OD600 measurements or viable cell counts—the InPro8100 employs a calibrated near-infrared (NIR) photometric principle operating at 850 nm, enabling continuous, drift-free quantification of light attenuation caused by suspended cells in opaque or viscous fermentation broths. Its solid-state optical architecture eliminates moving parts and requires no reagents, making it suitable for sterile, single-use, and reusable bioreactor systems operating under ISO 13485, FDA 21 CFR Part 11, and EU GMP Annex 11-compliant validation frameworks.
Key Features
- Stainless-steel 316L wetted parts with IP68-rated housing for direct immersion or sanitary inline installation
- Temperature-compensated NIR measurement engine with built-in Pt100 RTD for simultaneous process temperature correlation
- Self-diagnostic optics with automatic baseline drift correction via reference channel monitoring
- Configurable analog output (4–20 mA) with HART 7 protocol support for integration into DCS/SCADA systems
- Optional digital communication via Modbus RTU over RS-485 or Modbus TCP/IP for MES/DCS interoperability
- Calibration traceable to NIST-traceable optical density standards; field calibration supported using certified turbidity standards (e.g., Formazin or AMCO AEPA)
Sample Compatibility & Compliance
The InPro8100 is validated for use across diverse bioprocess media including bacterial fermentations (E. coli, Pseudomonas), yeast cultures (S. cerevisiae, P. pastoris), and suspension-adapted mammalian cell lines (CHO, HEK293). It maintains accuracy in high-viscosity environments (up to 20 cP) and tolerates transient foam, air bubbles, and particulate load variations typical of fed-batch and perfusion operations. The sensor conforms to IEC 61508 SIL2 functional safety requirements when deployed in safety-critical loops and meets ATEX/IECEx Zone 1 certification for hazardous area installations. All firmware and configuration data support electronic audit trails compliant with 21 CFR Part 11 Annex 11 requirements for data integrity in regulated biopharmaceutical manufacturing.
Software & Data Management
Sensor configuration and diagnostics are managed via METTLER TOLEDO’s iMonitor software suite—a Windows-based engineering tool supporting device parameterization, trend logging, alarm threshold setup, and calibration history archiving. Raw OD values are time-stamped and synchronized with external process variables (pH, DO, temperature) through OPC UA connectivity. Historical datasets export in CSV or ASTM E1382-compliant format for statistical process control (SPC) analysis and batch record reconciliation. For cloud-connected deployments, optional integration with METTLER TOLEDO’s LabX® Process Edition enables centralized fleet management, predictive maintenance alerts, and automated report generation aligned with ICH Q5A/Q5D quality guidelines.
Applications
- Real-time monitoring of growth kinetics in microbial fermentation for optimal feeding strategy execution
- In-process control of harvest timing in monoclonal antibody production using CHO cell cultures
- Continuous assessment of biomass viability trends during scale-up from seed train to production bioreactors
- Supporting Quality-by-Design (QbD) initiatives by providing high-frequency PAT data for multivariate analysis (MVA) modeling
- Integration with advanced process control (APC) algorithms for adaptive pH/DO setpoint modulation based on metabolic activity proxies
FAQ
Can the InPro8100 replace offline OD600 measurements in QC release testing?
No—it is intended for process monitoring and control, not final product release. Regulatory submissions require orthogonal methods (e.g., viable plate counts or flow cytometry) for specification compliance.
Is the sensor compatible with single-use bioreactors?
Yes—available with gamma-sterilizable, disposable flow-through housings rated for up to 100 kPa pressure and 60°C maximum operating temperature.
How often does the sensor require recalibration?
Under stable process conditions, annual verification against traceable standards is recommended; however, routine zero-point checks using clean buffer can be performed daily via iMonitor.
Does it measure viable vs. total cell count?
No—it reports total optical density proportional to total suspended solids (TSS); differentiation between live/dead cells requires complementary techniques such as fluorescence staining or dielectric spectroscopy.
Can it be installed in wastewater streams?
While the InPro8100 is optimized for biopharma applications, its sister model InPro8050 is specifically designed for municipal and industrial wastewater TSS monitoring per ISO 7027 and EPA Method 180.1.
