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KrosFlo® KR2i TFF System
Single-use fully integrated benchtop TFF system for research and process development (PD) ranging from 2mL - 15L. Compatible with hollow fiber and flat sheet filters, this system features a peristaltic feed pump with 13 automated process modes.
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Product features
Robust Processing
Ultrafiltration and diafiltration (UF/DF) processing for batch volumes ranging 2mL to 15L.
Easy to use
Plug and play configurability to add and remove components as needed with minimal effort.
Compatible with flat sheet cassettes and hollow fiber filters.
Walk-away automation
13 automated process control modes with the Automatic Back Pressure Valve (ABV) and intuitive software platform.
KR2i-optimized flow paths
ProConnex® Flow Paths designed for efficiency, flexibility, and reproducibility — streamlining TFF setup, reducing errors, and optimizing workflows in process development.
Modularity Made Easy with Plug-and-Play Configurability
KrosFlo KR2i TFF systems achieve an unparalleled combination of configurability and user-simplicity through modular, plug-and-play hardware. All components, either directly or indirectly, connect to the main pump, which then communicates with the KF Comm 2 software for control and monitoring.
More Capabilities, Still Simple.
Get more out of TFF with the flexibility to configure your system to better suit your application needs. Keep your process compact and minimal or expand your capabilities to more advance modes of operation by adding components. Switch back and forth between configurations all without compromising on ease of use.
Automate, Control and Visualize with KF Comm 2
Control the whole system, configure recipes and automate processes in as little as 4 clicks through the intuitive KF Comm 2 software.
- Conveniently installed on any device using the Windows Operating System
- Compatible with Chrome, Mozilla, Firefox and Microsoft Explorer browsers
- Automatic software and firmware updates
- Optional 21 CFR Part 11 package available
Still using legacy KF Comm software?
Walk-away automation for your lab
The days of manually adjusting screw clamps are over. A Repligen-exclusive technology, the Automatic Back Pressure (ABV) Valve adds transmembrane pressure (TMP) control to every TFF process, reducing operator hands-on-time, data logging and continuous monitoring while improving process reproducibility.
- Automatically adjust tubing pinch distance according to user-defined set-points
- Maintain uniform TMP throughout process run, decreasing membrane fouling
- Use with compatible tubing sizes 13, 14, 16, 25, HP15, 17, HP24, 18, HP35, 36, and HP36
TFF with In-Line Protein Concentration Management
No longer are you dependent solely on mass inputs and off-line fixed-pathlength UV-Vis spectrophotometers. Now, you can measure what truly matters in real-time with the KrosFlo KR2i RPM® System. Monitor concentration in real time during your UF/DF run and control your process.
KrosFlo KR2i TFF System Virtual Demo Series
In this 6-part series, Simon Detzner provides viewers with a virtual training on the KrosFlo KR2i TFF system. This training series will cover the following topics:
- Introduction to system components
- Installation of flow-path and filter
- KF Comm2 software overview
- Recipe creation
- Running a CFC/D/C experiment
- Recovery of product
- BONUS: Flat Sheet Cassette Installation
ProConnex® Flow Paths for KR2i
Designed for all stages of process development, ProConnex Flow Paths are engineered for efficiency, reproducibility and performance while keeping personal preference in mind. Choose from one of three options to start streamlining your TFF operations today:
- NEW ProConnex® TFF Self-Assembly Kits simplify early PD set-up. One flexible assembly kit has everything you need — just add a bottle, filter and go.
- ProConnex® Standard Flow Paths come fully assembled to minimize process variability, enhance sterility and save time.
- ProConnex® Custom Flow Paths are fully tailored to your process, pre-assembled, and gamma-irradiated—ideal for use in cGMP environments. Add a fully integrated Spectrum® Hollow Fiber Filter and you’re ready to plug and play instantly.
Available gamma-irradiated, endotoxin-free, and particulate-free.
Effortless scaling with a single standardized platform
Designed as a platform and not as standalone units, KrosFlo KR2i, KMPi, and FS lab scale TFF systems share the same components, software and controls across the entire family, allowing you to confidently standardize your process. Common process change challenges during scale-up are removed.
Cited in Published Research
The KrosFlo KR2i TFF System is used by researchers across academia and industry for applications spanning gene editing delivery, RNA therapeutics, extracellular vesicle engineering, and viral vector purification. Below is a selection of peer-reviewed studies citing the system.
Researchers at the Wake Forest Institute for Regenerative Medicine compared three methods — ultracentrifugation, polymer precipitation, and tangential flow filtration using the KrosFlo KR2i — for concentrating lentivirus-like bionanoparticles carrying CRISPR SaCas9 mRNA. The TFF method produced the most active particles, and was used to generate all nanoparticle material for the rest of the study.
Lu et al., Nucleic Acids Research, 2019. DOI: 10.1093/nar/gkz093
Eli Lilly researchers used the KrosFlo KR2i for buffer exchange during downstream processing of siRNA-lipid nanoparticles formulated with the ionizable lipid used in the FDA-approved Onpattro® therapy.
Estabrook et al., Nature Communications, 2025. DOI: 10.1038/s41467-025-63651-4
Scientists at Karolinska Institute and EVOX Therapeutics used the KrosFlo KR2i with 300 kDa hollow fiber filters to concentrate and diafilter engineered extracellular vesicles from HEK-293T and MSC cell culture media.
Zheng et al., Journal of Extracellular Vesicles, 2022. DOI: 10.1002/jev2.12290
Researchers at TH Köln used the KrosFlo KR2i TFF system for single-pass TFF trials to concentrate and purify HIV virus-like particles using hollow fiber modules across multiple molecular weight cutoffs.
Wolf et al., Membranes, 2022. DOI: 10.3390/membranes12121248
Northwestern University researchers used the KrosFlo KR2i to concentrate and purify engineered extracellular vesicles encapsulating AAV vectors for gene therapy research. (Preprint, not yet peer-reviewed.)
Boucher et al., bioRxiv, 2025. DOI: 10.1101/2025.07.02.662894
Click on the hotspots to explore different features.
System features at a glance
The fully integrated KrosFlo KR2i TFF System features a digital peristaltic pump, graphical LCD display, digital pressure monitor, KR2i Pump head, automatic backpressure valve, filter module stand, and KF Comm real-time data collection software.
Highly configurable and versatile, the KrosFlo KR2i utilizes a number user-defined set-points to run complex application processes with numerous built-in safety alarms and stops. The system can run up to two stackable pump heads for higher flow rates.
Components and Accessories
- IP 33 Enclosure
- 600 RPM pump with reversible drive
- 90-260 Vrms @ 50/60 Hz
- Standard Easy Load 3 Pump Head for precision tubing L/S number 13, 14, 16, 25, 17, and 18 provided.
- (Optional) Easy Load 3 pump head for high performance tubing L/S numbers 15, 24, 35, 36
- ETL listed and CE/UL/cUL marked
- Pump Drive Dimensions: 10.5 in x 8 in x 8 in
Konduit adds:
- End point conductivity control for UF /DF
- End point UV control for diafiltering free drug from drug delivery particles
- End point UV control for concentration of certain molecules
- UV alarm for membrane breakthrough
- A260 and A280 light sources available
Transducers
- Measures and displays 4 pressures: Feed Pressure, Retentate Pressure, Permeate Pressure, Transmembrane Pressure (TMP)
- User-defined pressure alarms and stop set-points
- Available with different connector types (Luer and TC) and selected materials of construction (PS, PC)
Related products
KrosFlo® KMPi TFF System
Fully automate 100 ml - 500 L UF/DF processes using an unparalleled combination of hardware integration with peristaltic pump, configurability and automation through modular, plug-and-play hardware.
KrosFlo® KTF TFF Systems
The KrosFlo KTF are a series of highly configurable single-use TFF systems for multiple unit operations, applications, and filter types. With volumes spanning across 1 to 5000L, users enjoy the unrivaled flexibility of processing large and small batch sizes within the same platform.
KrosFlo® RS TFF Systems
The KrosFlo® RS are a series of tangential flow filtration (TFF) systems engineered for an era of new modalities. These systems are single-use and cGMP compliant with features like end-to-end automation, minimal hold-up volumes, and effortless scalability. Support automated ultrafiltration and diafiltration (UF/DF) processes for batch volume ranges of 35mL to 2000L.
ProConnex® Flow Paths for Systems
ProConnex® Flow Paths for TFF and Chromatography processes are single-use and engineered for optimum performance, reproducibility and time savings. System specific flow paths provide speed and reliability. Configured flow paths prioritize process requirements and sterility.
Fluid Management
Own your process with ProConnex® — streamlined fluid management solutions that reduces risk, improves consistency, and accelerates your path to production.
Process Analytics
Our process analytics solutions, featuring Variable Pathlength Spectroscopy for at-line and in-line concentration monitoring systems, ensure that products meet required Process Analytical Technology (PAT) standards. These tools provide critical data for optimizing bioprocesses and ensuring compliance with regulatory requirements.
The KrosFlo KR2i TFF System handles UF/DF processing for volumes from 2 mL to 15 L. The minimum recirculation volume can be as low as 2 mL.
Yes. The KrosFlo KR2i TFF System works with Spectrum Hollow Fiber Filters (13 cm² to 3,700 cm²), TangenX SIUS Flat Sheet Cassettes (100 cm² to 5,000 cm²) and most third-party filter options. You can switch between filter types on the same system with minor hardware changes.
The KrosFlo KR2i TFF System is controlled by KF Comm 2 software for automating, controlling, and visualizing UF/DF runs in as few as 4 clicks. It installs on any Windows-based device and works with Chrome, Firefox, and Microsoft Edge browsers. An optional 21 CFR Part 11-compliant version, KF Comm 2C, adds electronic signatures, audit trails, and user access controls for regulated environments. Users on legacy KF Comm software can upgrade to KF Comm 2 at any time.
The KrosFlo KR2i TFF System features 13 automated process control modes, including concentration, diafiltration, C/D/C (concentration/diafiltration/concentration), constant feed concentration, and more. The Automatic Back Pressure Valve (ABV) maintains uniform TMP throughout the process run, enabling walk-away operation.
While optimal for research and process development applications, the KrosFlo KR2i TFF system can be upgraded with an optional 21 CFR Part 11 compliance package through the KF Comm 2C software, which includes LDAP authentication, audit trails, electronic signatures, user group and review/approval controls. For GMP-ready solutions, you may also consider the KrosFlo RS TFF system or KrosFlo KTF TFF System.
The KrosFlo KR2i TFF system is used across many bioprocessing applications including monoclonal antibodies (mAb), viral vector (AAV, lentivirus), cell and gene therapy, mRNA and lipid nanoparticle (LNP), vaccine purification, and exosomes.
Yes. The KrosFlo KR2i TFF System can be upgraded to the KrosFlo KR2i RPM System, which integrates the PATsmart™ FlowVPX for inline protein concentration monitoring during UF/DF operations, providing real-time feedback control.
The KrosFlo KR2i TFF system is part of the KrosFlo platform family. Process parameters developed on the KrosFlo KR2i can transfer directly to larger systems such as the KrosFlo KMPi (100 mL to 500 L), KrosFlo FS (up to 500 L), KrosFlo KTF (1 to 5,000 L), and KrosFlo RS Systems for cGMP manufacturing. Repligen application specialists are ready to work with you to identify solutions for scale-up.
The KrosFlo KR2i and KMPi share the same peristaltic pump architecture, KF Comm 2 software, and automation features, but are sized for different stages of a process. The KrosFlo KR2i is built for research and process development, handling volumes from 2 mL to 15 L. The KrosFlo KMPi is designed for larger-scale process development and clinical manufacturing, scaling up to 500 L.
Because both systems use the same software, control logic, and add-on accessories, processes developed on the KrosFlo KR2i transfer directly to the KMPi without re-validation of core parameters — making them part of a single scale-up platform rather than two unrelated systems.
Konduit is an optional add-on module for the KrosFlo KR2i TFF System that adds inline UV and conductivity monitoring to UF/DF processes. It enables automated endpoint control based on conductivity (for diafiltration) or UV absorbance (for separating free drug from drug delivery particles, or concentrating specific molecules), and includes a UV alarm to detect membrane breakthrough. Konduit is available with A260 and A280 light sources to support a range of nucleic acid and protein applications.
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