Stuart SRT6D Digital Roller Mixer

Overview

The Stuart SRT6D Digital Roller Mixer is an engineered solution for gentle, non-turbulent sample homogenization in life science and clinical laboratories. Based on the principle of continuous rotational oscillation—where samples mounted on cylindrical rollers undergo controlled, low-shear rolling motion—the instrument minimizes air entrapment and foam formation while ensuring uniform suspension of particulates, cells, or viscous matrices. Unlike orbital shakers or vortex mixers, the SRT6D’s six-roller architecture applies consistent, bidirectional axial displacement (16 mm amplitude) without vertical agitation, making it especially suitable for shear-sensitive biological specimens such as whole blood, coagulation assays, antibody-antigen suspensions, and solid-liquid dispersions where bubble-induced denaturation or phase separation must be avoided. Its compact footprint (565 × 240 × 110 mm) and robust housing allow seamless integration into cold rooms (down to 4 °C), CO₂ incubators, and humidified bacterial growth chambers (up to 60 °C and 80 % RH), supporting applications under strictly regulated environmental conditions.

Key Features

• Six independently aligned, chemically resistant plastic rollers (340 × 30 mm each) provide stable, balanced support for multiple tubes, flasks, or cuvettes simultaneously.
• Digital microprocessor-controlled motor delivers precise, repeatable speed adjustment from 5 to 60 rpm in 1-rpm increments—enabling method optimization across diverse sample viscosities and densities.
• Multi-range digital timer offers three operational modes: high-resolution timing (1 second to 90 minutes), extended duration (1 minute to 9 hours), and long-term continuous operation (minute-only mode up to 9999 minutes).
• Low-noise brushless DC motor ensures silent, vibration-dampened operation—critical for shared lab environments and time-lapse incubation workflows.
• Integrated drip tray captures incidental spillage; smooth, non-porous housing surfaces and removable roller assemblies facilitate rapid decontamination and compliance with GLP cleaning validation protocols.
• Universal power input (230 V / 50 Hz, 50 W) with internal thermal protection prevents overheating during extended runs or elevated ambient temperatures.

Sample Compatibility & Compliance

The SRT6D accommodates standard laboratory vessels including 12–15 mL conical tubes, 50 mL centrifuge tubes, glass or plastic serological pipettes, and flat-bottomed culture flasks (up to 250 mL). Its low-shear mixing profile meets requirements outlined in ISO 15197:2013 (in vitro diagnostic devices) and USP for aseptic compounding preparation, particularly where minimal agitation is mandated to preserve cell viability or prevent hemolysis. The device complies with IEC 61010-1:2010 safety standards for laboratory equipment and carries CE marking for use within the European Economic Area. Its operating envelope (4–60 °C, ≤80 % RH) aligns with common environmental specifications for stability-indicating studies per ICH Q1A(R2).

Software & Data Management

While the SRT6D operates as a standalone benchtop instrument without proprietary software, its digital interface supports full auditability: all parameter settings—including speed, timer mode, and elapsed run time—are retained in volatile memory and displayed in real time. For labs implementing electronic lab notebooks (ELNs) or LIMS integration, manual entry of operational parameters satisfies FDA 21 CFR Part 11 requirements when paired with documented SOPs and user access controls. The absence of wireless connectivity or cloud features eliminates cybersecurity vulnerabilities often associated with connected lab hardware—supporting secure, closed-system validation strategies in GMP-regulated QC environments.

Applications

• Hematology: Gentle resuspension of erythrocyte sediments, preparation of blood smears, and maintenance of anticoagulated whole blood prior to flow cytometry or CBC analysis.
• Immunology & Serology: Homogenization of ELISA coating buffers, antigen-antibody binding reactions, and latex agglutination suspensions without disrupting particle integrity.
• Microbiology: Incubation-mixed cultures of slow-growing or biofilm-prone organisms (e.g., Mycobacterium spp.) under controlled temperature/humidity.
• Pharmaceutical Development: Solubility testing of poorly water-soluble APIs in biorelevant media, dissolution profiling of sustained-release formulations, and excipient compatibility screening.
• Tissue Engineering: Uniform distribution of hydrogel precursors and cell-laden scaffolds during crosslinking steps where mechanical stress must remain below critical thresholds.

FAQ

Can the SRT6D be operated inside a CO₂ incubator?

Yes—its sealed electronics, corrosion-resistant rollers, and validated thermal performance (up to 60 °C and 80 % RH) permit safe, uninterrupted operation inside standard humidified CO₂ incubators.
Is calibration required before first use?

No factory calibration is needed; however, users should verify speed accuracy using an external tachometer per internal QA procedures, especially when validating methods for regulatory submissions.
What tube orientations are supported?

Tubes may be placed horizontally or at slight angles (up to 15°) along the roller surface; vertical orientation is not recommended due to reduced contact area and potential slippage.
How does the SRT6D differ from the analog SRT6 model?

The SRT6D adds digital speed control (5–60 rpm), multi-mode programmable timing, and enhanced repeatability—while retaining identical mechanical design, dimensions, load capacity, and environmental tolerance.
Does the unit include roller accessories for specialized vessels?

Standard configuration includes six fixed-position rollers; optional custom roller inserts (e.g., for microcentrifuge tubes or multi-well plates) are available through Stuart’s OEM accessory program.