Platform comparison of binding kinetics of Nivolumab

The pharmacological response of a biological drug is profoundly influenced by its non-specific binding to serum proteins. Interactions with blood proteins affect conformational changes and modulate the efficacy of the drug, which in some extreme situations cause antagonistic drugs to lose their capacity to bind to their receptors. How strongly a drug protein binds to its target molecule alters the drug’s potency, dosing regimen and degree of on-target side effects. Unfortunately, the platforms typically used to measure binding strength, such as those relying on Surface Plasmon resonance (SPR) or Bio-Layer Interferometry (BLI), are unable to consistently and reliably measure protein binding kinetics in a physiologically relevant system. 

In contrast, the MagArray Protein Binding Kinetics platform can measure protein binding kinetics precisely, reproducibly, and with great sensitivity in physiologically relevant matrices.  A recent comparison study of the kinetics of Nivolumab binding with PD-1 in increasing concentrations of serum, demonstrated the MagArray platform can measure binding on rates and off rates when the SPR and BLI systems cannot. 

The MagArray platform was able to provide a reliable and rapid approach to obtaining binding kinetics parameters in physiologically relevant matrices while the SPR platform could not measure the kinetics in a matrix containing more than 0.5% serum. The BLI platform could not measure binding kinetics in the presence of any amount of serum. 

Given the profound impact that cancer immunotherapies are having, and the rapid increase in the number of antibody checkpoint inhibitors being investigated, the importance of examining their binding kinetics in a physiologically relevant matrix is critical to understanding exactly how such immuno-oncology inhibitors are likely to behave in-vivo

To learn more about how the MagArray Protein Kinetics platform can help your drug discovery and characterization efforts, click here, or reach out to Kalidip Choudhury, Ph.D 

MagArray Lifesciences 

Giant Magnetic Resonance (GMR) Assay Principles

Our platform utilizes a sandwich assay in which the target antigen is sandwiched between two antigens, one bound to the magnetic sensor and the other to a superparamagnetic nano particle. Under an external magnetic field, the nanoparticles magnetize and their presence or absence can be detected by the sensor. Using chips with 64 GMR sensors we show rapid multiplex protein detection with a liner dynamic range of over 5-6 orders of magnitude for a diverse range of biological fluids in real time.



 *Based on standard LBA process with magnetic nanoparticles used as labels

Instrument and chip

GMR Multiplex Chip

  • 80 individual sensors on each chip
  • 8 chips with 640 sensors total
  • Each sensor can be individually spotted
  • 80 biomarkers with controls for the multiplex chip

GMR Reader Unit

MagArray MR-813 Reader Unit
  •  Rugged and reliable
    • No optics meaning no calibration of lasers, mirrors etc
    • No fluidics means no pumps, valves, etc
  •  Fully automated
    • Hands free incubation
    • Bar code system to minimize errors
  • No wash necessary
  • Flexible assay protocols
    • Run time of 1 hour for most sensitive assay
    • Run time of 5-10 minutes for express assays

Multiplex Immunoassay

MagArray has 5-6 orders of magnitude greater dynamic range and a 1000 times more sensitive than ELISA.

Compared to ELISA, the MagArray platform is capable of detecting CEA at significantly lower concentrations and at 5-6 orders of magnitude greater dynamic range utilizing the same Ab pair

Matrix insensitive detection in different buffers.

A panel of eight human tumor markers with BSA negative control and epoxy control indicates matrix insensitive detection when shifting from PBS to mouse serum to lysis buffer

Ligand Binding Assay

Our GMR platform is more sensitive than SPR and insensitive to buffer conditions

graphic 6

MagArray platform at least 1000 times more sensitive than Biacore/SPR

MagArray platform insensitive to pH and salinity*

The effect of matrix on protein binding between SPR and MagArray

Buffer: 0.01M HEPES, pH 7.4, 0.15M NaCl, 3mM EDTA 
Regeneration: 10mM Gly-HCL, pH 2.5 
Analyte: TSH, Ligand: Anti-TSH ab

Biacore X 100

KD-Comparison Graph
  • The same binding pair and buffer conditions were used to compare between MagArray and Biacore
  • Plasma was used as a matrix and diluted by PBS to 80%, 50%, 10%, 1%, 0.1%
  • MagArray platform kinetic measurements were not affected by matrix
  • Biacore did not provide reliable results above 0.1% matrix


  • Truly a transformational platform that helps to bridge the gap between in-vitro and in-vivo.
  • Matrix insensitive technology for measuring biomolecules in blood, plasma, serum, saliva and urine.
  • 1000 times more sensitive than leading SPR technologies in measuring protein-protein interactions.
  • Partnership with Hitachi Hi-Technologies allows expansion of platform for unmet needs in biological assays.


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