UC customers: $129/hr
DARTs/NonProfits: $171/hr
External/For Profit: $250/hr

For questions, and to reserve machine time,  please contact unit director Alexey Tomilov, PhD, at atomilov@ucdavis.edu, or call 530-902-1051.

BLI is an optical analytical technique that measures interference patterns between waves of light (Figure 1). White light is directed down a fiber-optic biosensor towards two interfaces: an internal reference layer (Figure 1A), and a biocompatible layer on the surface of the tip (Figure 1B). A thin layer at the tip of the fiber separates these interfaces. Light reflects from each of the two layers, and the reflected beams interfere constructively or destructively at different light spectrum wavelengths; a CCD array detector measures this interference pattern.

Target molecules bind to the two-dimensional coated surface when the tip of a biosensor is dipped into a sample. This molecular layer increases in thickness when more target molecules bind to the surface. As the thickness of the layer increases at the biosensor tip, the effective distance between the two reflective layers increases, creating a shift in the interference pattern of reflected light (Figure 1C). The spectral pattern of the reflected light therefore changes as a function of the molecular layer optical thickness, i.e. the number of molecules bound to the biosensor surface. This spectral shift is monitored at the detector and reported as a change of wavelength (Response [nm] shift) on the Octet® sensorgram.

ForteBio Octet® RED384 Instrument Software

Please visit the Octet® RED384 manufacturer website for information regarding available data analysis software packages:
https://www.sartorius.com/en/products/protein-analysis/octet-systems-software 

This image shows Octet® RED384 analyzer sensorgram output of a small molecule binding to proteins of interest.

ForteBio Octet® RED384 Instrument

General information about the Octet systems can be found here:
https://www.sartorius.com/en/products/protein-analysis/octet-label-free-detection-systems 

Bio-Layer Interferometry (BLI) Technology

Octet® Real-Time Drug and Protein Binding Kinetics Unit

Unit director Alexey Tomilov, PhD, stands in front of the Octet® RED384 instrument.

Equipment Description and Usage Service

Octet Instrument

Octet Recharge Facility Rules

PLATE-BASED and High Throughput Assay Assistance, Hourly Rates

1. Users provide following information at the beginning of the experiment: Name, PI, Department, Tel., Contact Email, and Recharge Number.

2. No Radioactive, Acutely Toxic, Toxic, Hazardous, Corrosive, or Flammable materials are allowed in the Instrument

3. Users are responsible for purchasing their own supplies, buffers biosensors and assay plates as listed on the Cortopassi lab website: https://www.cortopassilab.com/octet-instrument.html

4. Users are responsible for preparing all necessary reagents and for pipetting their experimental components onto their assay plates, and are encouraged to bring their own pipettes and tips. If User would need to use Cortopassi lab pipette, ask Instrument Operator.

5. Instrument Operator loads the experimental protocol (“method file”) into the Instrument Controller Software and executes Users protocols on the Instrument. Instrument Operator controls the Instrument robotics. Instrument Operator can create the "method file", if requested by User, according to the goal of the experiment.

6. Users are required to be familiar with UC Davis Safety policies and training, adhere to UC Davis Safety rules, and be able to provide appropriate documentation. Users are required to have appropriate PPE while in the laboratory space; the facility have extra lab-coats and gloves to facilitate Users.

7. Users will be charged Recharge Hourly Rate according to the timing recorded in the Log File the Instrument Control Software automatically creates.

The ForteBio Octet® RED384 equipment is available for recharge use at the UC Davis Octet® Real-Time Drug and Protein Binding Kinetics Unit.The Octet system provides researchers the opportunity to perform high-throughput, real-time, drug-protein and protein-protein binding kinetics in an expedited manner compared to traditional techniques. This machine is a relatively new technological advancement and is the only one available in Northern California except UCSF.

The Octet® system provides many advantages over traditional methods for detecting drug- protein and protein-protein interactions. The high-throughput aspect of the system means that a library of small molecules or known proteins can be screened for interaction with a protein of interest both quickly and at large scale. The Bio Layer Interferometry (BLI) Technology provides real-time protein-small molecule or protein-protein association and dissociation kinetics. The high sensitivity of the assay means that much lower protein amounts are required for analysis compared to traditional immunoprecipitation, NMR, or ELISA methods. In addition, crude protein extracts may be used, and the Octet® system has considerable flexibility to work with both labeled and non-labeled protein targets.

Use charges for the Octet: Users buy biosensors and plates, and pay for machine time.  

Users order the biosensors from Forte Bio biodensor list: https://www.sartorius.com/en/products/protein-analysis/biosensors-and-kits; choose the BLI Biosensors tab, and pay for them with a credit card or UCD Purchase Order number. 

Users order micro-plates. If you planning to test a small molecules binding to a target protein of interest, or you would like to use small (100ul) samples volumes you need to order 384 well micro-plates from Forte Bio (384 well), Part number 18-5076 (Case) or  18-5080 (Pack of 10 plates, ~$15/plate): https://www.sartorius.com/shop/ww/en/usd/search?search=18-5076. These plates have a tilted bottom, alowing the light not to be reflected back into the instrument optics, thus, increasing sensitivity and accuracy of measurements. These micro-plates are not re-usable.

If you are planning to study macromolecular interactions, such as Protein-Protein interaction (PPI), Protein-DNA/RNA, Antibody binding, Peptides, or planning to study blocking of PPI agents (iPPI), and like to use larges sample volumes (200 – 250 uL), you would need to order 96 well plates. The 96-well plates can be ordered from greiner bio-one, Greiner Bio-One: GBO (grainer bio-one, MICROPALTE 96 WELL, PS, F-BOTTOM (CHIMNEY WELL) BLACK, NON-BINDING, 10 PCS/BAG. REF 655900): https://shop.gbo.com/en/usa/products/bioscience/microplates/non-binding-microplates/96-well-non-binding-microplates/655900.html. 

These micro-plates are re-usable and facilitate larger sample volumes to reduce the effects of evaporation and allow more accurate pipetting to achieve specific concentrations. These plates are good if you are planning to use long association and dissociation times.

Users are encouraged to purchase and use the “Kinetics Buffer” specifically designed for binding assays with Octet systems. The composition is 137 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 1.8 mM KH2PO4, 0.02% Tween-20, 0.1% BSA, 0.05% Sodium Azide, pH=7.4, the reagents used to make this buffer are very high grade, and we found that it is cheaper to purchase it, than to make it yourself: https://www.sartorius.com/shop/ww/en/usd/products-protein-analysis/octet-kinetics-buffer-10x/p/Bio-Layer-Interferometry-Kinetic-Buffer. Users can also use any buffer of choice; however need to make sure that chemistry is compatible with buffer components. For example to use Ni-NTA biosensors, the buffer should not contain imidazole, EDTA or other reagents capable to compromise the Ni-NTA biosensors.