Biolayer Interferometry for Label-Free Biomolecular Interaction Analysis

For over 20 years, we have dependably supported our customers by creating established fluidic-free Biolayer Interferometry (BLI) platforms, consumables, and software. These products are trusted by scientists worldwide to support their bioanalytical needs for protein interaction analysis spanning from drug discovery to antibody engineering to bioprocessing and quality control (QC).

Our dedication to quality is reflected in an install base of more than 3,500 customers and is well-documented in more than 7,000 customer publications.  Over the years, our top priority has been providing exceptional technical and scientific support, ensuring you can quickly and effectively utilize our products to achieve your experimental goals.

We continue to shape the future with Octet®, the only brand currently combining both industry-leading label-free technologies – Biolayer Interferometry (BLI) and Surface Plasmon Resonance (SPR) for real-time label-free measurements of binding kinetics and affinity or to determine the active concentration of an analyte.

Introducing Octet® BLI Solutions

Performance, flexibility and confidence for real-time label-free, high-quality binding kinetics and analyte quantitation.

Octet®️ BLI systems offer an advanced, fast, robust, and fluidics-free approach for protein-protein and protein-small molecule analysis. The Octet®️ BLI platform allows direct detection of specific proteins or drug molecules - even in complex mixtures and unpurified samples such as cell culture supernatants and lysates. 

Always opt for the genuine Octet® platform to empower your research by enabling faster time to market, quicker project completion and greater project capacity.

Request a Quote, Demo or More Information

Biolayer Interferometry (BLI) Instruments

The Octet® BLI is an easy-to use, real-time analytical tool that rapidly screens critical quality attributes.

2-Channel System: Octet® R2

Grows with your biomolecule characterization needs

Explore Octet® R2
Octet R4 label free detection system

4-Channel System: Octet® R4

The perfect balance between cost and throughput with given leeway

Explore Octet® R4
Octet R8 label free detection system instrument

8-Channel System: Octet® R8

Unmatched flexibility and versatility in protein analysis

Explore Octet® R8
Octet® BLI rapidly determines recombinant protein concentration as a control parameter in cell line development.

96-Channel Ultra High Throughput Octet System: Octet® RH96

Monitors up to 96 biosensors simultaneously, enabling label-free detection for protein quantitation and kinetic characterization at unmatched speed

Explore Octet® RH96
Octet RH16 ultra high throughput label free detection system

16-Channel High Throughput Octet System: Octet® RH16

Ideal for high-throughput applications that demand high sensitivity and low sample volume requirements

Explore Octet® RH16
Octet N1 label free detection system

Personal Assay Octet® N1 System

Affordably priced label-free analysis for individual researchers on any budget

Explore Octet® N1

Explore BLI Consumables, Software and Support

Octet biosensors

Biosensors & Kits

Available in a wide range of surface chemistries for use in a diverse set of biomolecular applications.

Explore Biosensors & Kits
GxP Compliance

GxP Compliance Tools

A wide range of compliance tools for developing validated assay methods on the Octet® BLI platform.

Explore GxP Tools
Lab technicians with Octet RH96

Octet® Systems Software

Facilitate data acquisition and data analysis in laboratories working under GMP, GLP and 21 CFR Part 11 regulations.

Explore Software

Octet® System Service and Support

Receive outstanding assistance for both technical issues and assay-related enquiries.

Explore Service & Support

BLI Promotions

Protein Analysis Octet BLI and SPR instruments playing cards
Biolayer Interferometry

Bundle Octet® BLI and SPR Systems and Save

Global - Get up to $190K (€160K) off when you bundle Octet® BLI and SPR systems

See Promotion

20 Years of BLI Expertise

Octet® R8 touchscreen

Two Decades of Supporting Groundbreaking Scientific Research

Proven countless times – the genuine Octet® BLI is an industry-leading technology with more than 7000 peer reviewed publications covering a large variety of research areas and applications. The Octet® Publication Database provides an easy way to search scientific publications that reference and/or cite the use of our Octet® products for label-free biomolecular interaction analysis in real time. 

Discover Our Literature Search Tool

Octet® Publication Database

Literature references covering a large variety of research areas and applications

Search Featured Publications
Lab technicians with Octet RH96

Break Free from Bargain Imitations — See What Genuine Octet® BLI Users Are Saying

Thousands of researchers worldwide use Octet® systems in diverse fields ranging from drug discovery to biopharmaceutical development and academic research to determine binding specificity, active analyte concentration, affinity, or binding kinetics in real-time.

Discover what users of genuine Octet® BLI have to say about this indispensable tool that has helped them advance their research and accelerate the development of new therapeutics and diagnostics.


Easy to use, speedy and robust.

Application Area: High-throughput antibody characterization and small molecule analysis

"The Octet® RH96 lets our team carry out quantitation at high-resolution that is comparable to an HPLC and rapid throughput. It allows shortening of our experimental timelines and less cost for cell line development projects. Our team uses it for label-free, real-time data generation and it's a facile instrument to use that provides superior quality data at a very cost-efficient price." 

- Sankalp Gupta, Sanofi

Really wonderful instrument definitely can't live without it!

Application Area: High throughput mAb characterization and small molecule analysis

"We use it for label-free, real-time data generation. The Octet® RH96 is a facile instrument to use and provides superior quality data at a very cost-efficient price."

– Kesh Prakash, Emergent BioSolutions

The ease of use, robustness, speed, and costs make this an exemplary instrument.

Application Area: HTS drug development screening tool

"The Octet® RH96 allows quantitation with high resolution comparable to an HPLC and rapid throughput. The platform allows shortening of our timelines and less cost for cell line development. The instrument is very robust, easy to use and is well supported by an experienced support staff of application scientists, software engineers, service engineers and sales. Integration of the instrument into an automation system was completely supported by the vendor."

– Glenn Yamasaki, Bayer Healthcare

Would buy that instrument again.

Application Area: IgG Quantitation in Cell Line Development

"Easy to use instrument [Octet® R8], good results. Easy to explain to new users. Great support."

– Julius Grzeschik, Ferring Pharmaceuticals

First choice for interaction studies.

Application Area: Drug discovery

"Octet® is very easy to use system for fast screening of protein - small molecule interaction studies. Easy to maintain and definitely value for the money because of time saved in measurements time."

– Juha Määttä, Tampere 

Great results, can’t live without this instrument!

Application Area: Drug discovery

"State of the art technology"

– Hailan Yao, Roskamp Institute

Octet® Performance: Sensitive, Clean, and Reproducible Data

Baseline Stability, Low Noise, and Low Baseline Drift are Key for High-Quality Data

The Octet® R Series offers an advanced, fluidics-free approach to bimolecular analysis, with a wide variety of off-the-shelf biosensors for rapid binding kinetics and quantitation analysis. These systems utilize Sartorius’ genuine label-free Biolayer Interferometry (BLI) technology, enabling direct detection of specific proteins and other biomolecules — even in complex mixtures like crude cell culture supernatants and lysates.

The Octet® BLI systems monitor binding events in real time to calculate on rates (ka), off rates (kd) and affinity constants (KD). The superior sensitivity enables measurement of low molecular weight molecules down to 150 Da. The following example shows the kinetic interaction analysis of a small molecule.

Figure 1. The kinetic analysis of between a ligand, biotinylated-carbonic-anhydrase, and the small molecule analyte Furosemide (330.7 Da) with Super Streptavidin (SSA) Biosensors at 1000 rpm and 25°C on an Octet® R8 system. Furosemide working solutions were prepared in serial dilutions of 0.1, 0.3, 1.0. 3.0, 10.0 µM (n=4), respectively. Data was processed and curve fitted using a 1:1 binding model. 

High Resolution and Low Noise to Measure High Affinity Interactions 

Slow off-rate measurements show minimal changes in signals in the dissociation step requiring a combination of stable baselines and low baseline drifts for accurate measurement of the dissociation phase.

In addition, capturing measurable dissociation of the interaction may take hours of (> 2 hr data acquisition) specifically at the dissociation phase of higher affinity interactions that exhibit very slow off rates. Therefore, measuring longer dissociation times is also critical for measuring high-affinity interactions.

The Octet® R8 system simultaneously enables measurements of up to 8 samples in a single unattended run. Combined with a unique microplate cover that keeps samples intact by minimizing evaporation, it allows scientists to collect accurate measurements with evaporation control for up to 12 hours.

The measurement of one high-affinity interaction measured in triplicates in a long dissociation experiment on the Octet® R8 system is demonstrated below. Full kinetic characterization of an antibody-antigen interaction was run three times with a total run time of 11 hours.

Figures 2 and 3 provide two examples of long dissociation measurement over several hours to allow the detection of very slow off-rates.

Figure 2. A high-affinity interaction between an IgG and Fab measured in triplicates that required a long dissociation step time of more than three hours was measured using an Octet® R8 system. The total experiment run time was 11 hours for measurements made in triplicate.

Figure 3. Kinetics of high-affinity interaction between Human Epidermal Growth Factor (HER2) protein and anti-HER2 monoclonal antibody (Herceptin) analyzed in the Octet® R8 system demonstrating reliable high-resolution kinetic data.

Applications for Biolayer Interferometry

Potential Applications of Label-Free Octet® BLI

Binding Kinetics
  • Protein-protein interactions
  • Antibody characterization
  • Antibody-antigen binding
  • Protein-small molecule interactions
  • DNA-aptamer binding
  • Bacteria-antibody interactions
  • Virus-like particle-antibody/protein binding
  • Epitope binning
  • GPCR-protein binding
  • Off-rate ranking
  • Affinity maturation
Analyte Quantitation
  • Antibody quantitation
  • Protein Quantitation
  • AAV titer
  • Glycosylation profiling
  • ELISA replacement
  • Protein quantitation in crude extracts
  • Detection of contaminations
  • Expression monitoring
  • Immunogenicity
  • Vaccine-induced antibody responses
  • Potency assays
  • Screening for binders (hybridoma, page, or lysates)
  • DNA-aptamer screening
  • Secondary screening and hit validation
  • Inhibitor screening
  • Clone selection
Assay Development
  • Formulation development
  • Media development
  • Cell line development
  • Cell line optimization
  • Lateral flow assay validation

Featured BLI Resources

Educational Resources

7000+ Octet publications New

Octet® Publication Database

Literature references covering a large variety of research areas and applications

Search Featured Publications

Label-Free Techniques for Biologics Assessment

When investigating biological mechanisms and developing new therapeutics, BLI and SPR offer unique advantages

Access eBook
A compendium for successful BLI and SPR assays
Application Guide

A Compendium for Successful BLI and SPR Assays

A comprehensive guide for designing and performing assays that accurately measure the binding kinetics of biomolecular interactions and analyte concen...

Access the Guide
harmonizing regulatory guidelines for assay validation application note cover
Application Guide

Harmonizing Regulatory Guidelines for Assay Validation

Current regulatory guidelines for assay validation were harmonized for kinetic-based assay to derive a common set of parameters.

Access the Guide

Octet® BLI Products are Confidently Adopted in Regulated Environments

Not Just GxP Compliance Tools — Rely on a Comprehensive Toolbox

From antibody quantitation, ligand binding characterization to potency assays, Sartorius offers a wide range of GxP compliance tools for developing validated assay methods on the genuine Octet® BLI platform.

The United States Pharmacopeia (USP) has recently released a new general chapter <1108> which for the first time cites the use of biolayer interferometry in key ligand binding applications that provide more precise kinetic data and that can measure a relatively wide range of binding affinities. Read More

Sartorius Offers Octet® 21 CFR Part 11 Software and a Full Line of GxP Products and Services as Part of the Octet® GxP Package Including Our Biosensor Validation Support Services

This service enables the Octet® BLI users to sample multiple lots of a biosensor during assay qualification and validation and reserve a well-characterized lot for purchase. Hence, customers can order up to five different biosensor lots, up to 20 trays from each lot for evaluation, and reserve up to 40 additional trays for future purchase.

Contact Us to Explore Octet® GxP

Approved Drugs Utilizing Octet®️ BLI Data in Their Regulatory Approval Process

Octet®️ BLI assays can help identify potential safety concerns and improve the accuracy of drug evaluations. Here are several examples of companies, including Pfizer, AstraZeneca, or Roche, who have utilized such assays to generate data submitted as part of the supporting information for the drug’s approval with regulatory bodies such as the FDA or the EMA.

Explore Examples of Approved Drugs Using Octet® BLI

Frequently Asked Questions

Biolayer Interferometry (BLI) is a label-free technology for measuring biomolecular interactions. It is an optical analytical technique that has gained popularity in the fields of biochemistry, biology, and medical research due to its real-time, high-throughput analysis capabilities.

Biolayer Interferometry (BLI) is a label-free analytical technique commonly used to study biomolecule interactions. It is based on the principles of optical interferometry, where changes in the thickness of a biological layer constructed on a biosensor tip cause shifts in the interference pattern of white light reflected from the biolayer. This shift in the interference pattern correlates to real-time layer thickness changes, which allows for monitoring molecular binding and dissociation.

BLI is especially useful in providing quantitative data on the analyte concentration, binding kinetics, binding affinity, and specificity of biomolecular interactions without requiring fluorescent or radioactive labeling. This makes it a popular choice in various fields, such as drug development, antibody testing, and protein analysis.

In BLI, a biosensor tip is dipped into a solution containing biomolecules. These molecules bind to the biosensor, forming a thin biological layer. The interference pattern changes as more molecules bind to the biosensor, causing a shift in the wavelength of the reflected light. By monitoring this shift, scientists can track the binding process in real-time. This allows them to measure the rate of association (ka) and dissociation (kd), as well as the binding affinity (KD) of the interaction, providing valuable insights into the biomolecular interaction of a wide variety of molecules.

Biolayer Interferometry (BLI) offers several advantages over other biomolecular binding analysis methods such as Surface Plasmon Resonance (SPR) and Enzyme-Linked Immunosorbent Assay (ELISA). Here are some of the key benefits:

  1. BLI is a label-free technique that eliminates potential interference from labeling, allowing for the analysis of unmodified biomolecules.
  2. BLI provides real-time analysis of biomolecular interactions, including binding kinetics, affinity, and concentration.
  3. Compatibility with Diverse Sample Types: BLI can be used with a range of sample types, including crude samples or samples in complex matrices, without significant interference
  4. Requires minimal or no sample preparation, which is beneficial for high-throughput screening.
  5. Wide Range of Applications: BLI can be used to study various interactions, including protein-protein, protein-DNA/RNA, protein-small molecule, and even cell-based interactions. This versatility makes it applicable in many research and development contexts.
  6. Low Sample Consumption: BLI typically requires a small sample and can be reused, which is advantageous when working with precious or limited materials.
  7. Ease of Use and High Throughput: BLI instruments are generally user-friendly and capable of handling multiple samples simultaneously, making them suitable for high-throughput screening applications.
  8. Cost-Effectiveness: Compared to some other techniques, BLI can be more cost-effective, especially in terms of reagent use and maintenance of the equipment.

Biolayer Interferometry (BLI) has great potential in various fields, including biomedical research, drug discovery, and diagnostic development. It is a highly effective tool for antibody characterization and for exploring interactions between proteins and small molecules, which can significantly aid in therapeutic development.

BLI can be useful in biosimilar production, assessing vaccine efficacy, and quality control for protein therapeutics. It is also beneficial in studying cellular signaling and gene regulation through interactions between ligands and receptors, and nucleic acids and proteins. In the biopharmaceutical industry, BLI can play a critical role in ensuring quality control and can help in the development of diagnostic tools for detecting disease biomarkers, highlighting its wide-ranging applications in life sciences.

BLI biosensors operate on the principle of interferometry employing a white light source, which emits light across a broad range of wavelengths. The interference between the light reflected from the top of the biological surface on the sensor tip and the light reflected from an internal reference layer creates an interference pattern. This pattern is captured by a detector, typically a spectrometer or photodetector, and is used to measure changes in the interference signal. These changes in the interference pattern are directly related to the biomolecular interactions occurring on the sensor surface.

Biolayer Interferometry is a powerful and versatile technology that provides a valuable tool for studying biomolecular interactions. Its ability to provide real-time, label-free analysis makes it an invaluable tool in advancing the understanding in biochemistry, biology, and medical research, contributing significantly to the development of new drugs and therapies.

Request a Quote, Demo, or More Information

What other areas are you interested in? (select all that apply)

Experience the Octet® Difference - Request a Quote, Demo, or More Information

Follow Octet® on LinkedIn

Get the Latest Updates, Trends and Developments on Label-free, Stress-Free Solutions for Drug Discovery, Biologics Development and Biomanufacturing.

Follow Us Now

Related Content


Applications for Label-Free Detection

Explore More

Octet® System Service and Support

Explore More

Octet® BLI Resources

Explore More