BLI & SPR Real-time Affinity Measurement Services

Overview BLI vs. SPR Applications Service Details Case Studies Contact Us

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Overview

BLI (Bio-Layer Interferometry) and SPR (Surface Plasmon Resonance) are powerful label-free optical techniques commonly used to study molecular interactions in real-time, with unique features ideal for studying protein binding, quantitation, affinity, and kinetics.

BLI works by analyzing the interference pattern of white light reflected from an immobilized protein layer on the biosensor tip and an internal reference layer. Only molecules binding to or dissociating from the biosensor cause shifts in the interference pattern.

SPR uses polarized light to excite surface plasmons at a metal-dielectric interface, causing a drop in reflected light intensity at a specific angle. When molecules bind to the metal surface, they change the local refractive index, shifting the resonance angle. This shift provides detailed information into binding kinetics and interaction affinity.

Biacore 8K

Sartorius Octet^RED

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Protein Services

BLI vs. SPR

	BLI	SPR
Common Advantages	Target-free, Real-time detection	Target-free, Real-time detection
Instruments	Sartorius Octet^RED (16 channels)	Biacore 8K (8 channels)
Samples	Sample types: suitable for expression supernatants Buffer compatibility: tolerant to organic reagents Sample recovery: available	Sample types: can detect small molecules (~100 Da); not suitable for crude samples Buffer incompatibility: high refractive index (glycerol, sucrose); amino groups (Tris)
Detection Range	Lower sensitivity for low-affinity or hard-to-dissociate samples Comparable results to SPR for moderate affinity (KD µM~nM)	High sensitivity and broader affinity detection range Suitable for samples with lower affinity (KD ~µM) and higher affinity (KD ~0.1 nM)
Service	Antigen affinity measurement-affinity ranking (1 concentration) Antigen affinity measurement-Kinetics (5 concentrations)
Timeline	Starting from 8 days
Deliverables	Analysis Report (Ka, Kd, KD)

BLI High Throughput Package

For high-throughput demands, our proprietary BLI HT service accelerates early-stage discovery—classifying molecular binding as positive, negative, or ambiguous. We offer cost-efficient bundles that seamlessly integrate gene-to-protein expression and affinity measurement in as fast as 8 days.

Discover how our tailored bundles and exclusive promotions can accelerate your projects —get in touch to learn more!

TurboCHO™ Antibody Expression + BLI HT

Fast Speed
8 days till results

Cost effective
From $136/design

Large Capacity
1000+ designs per day

High Affinity
Antibody

Learn More about TurboCHO™

Cell Free Protein Synthesis + BLI HT

Fast Speed
8 days till results

Cost effective
From $120/design

Large Capacity
1000+ designs per day

Protein type
VHH, ScFv, miniproteins

Learn More about Cell Free

Applications in Antibody Drug Discovery

BLI and SPR are essential technologies in protein discovery, unravelling precise biomolecular interaction insights critical for characterizing therapeutic antibodies. Explore our interactive workflow diagram to see how these platforms deliver value at every stage of antibody discovery!

Beyond antibodies? Our BLI/SPR solutions power diverse applications—Book a call to tell us your focus!

Gene to Hits

Hits to Leads

Candidates Selection

Discovery & Target
Identification

Hits Screening

Lead Indentifaction
& Validation

Lead Optimization

In vivo & vitro Assays

GLP Tox

0.05mg

500mg

200g

TurboCHO™ HT

TurboCHO™ Express

TurboCHO™ HP/TurboCHO™ Stable

Target Identification

Protein-protein interactions
Protein-small molecule/natural
product/extract interactions
Protein-DNA/RNA/Peptide interactions

Lead Identification

Compound library/clone screening
(hybridoma, phage display, lysate,
cell expression supernatant)
Affinity/k_off ranking
Epitope binning

Lead Optimization

Fc engineering/humanization
FcγRs/FcRn binding activity
Epitope mapping

Case Studies

Case 1: SPR – IgG Affinity –SPR has high sensitivity and broad affinity detection range (KD = 10^-3-10^-15)

As shown in Fig 1 and Tab 1, SPR has higher sensitivity and a wider affinity detection range than BLI. SPR is suitable for both low-affinity (KD ~µM) and high-affinity (KD ~0.1 nM) samples, which may not be successfully detected by BLI.

Figure 1: Affinity binding curves of human IgG-1, 2, 3

Human IgG-1

Human IgG-2

Human IgG-3

Table 1: Affinity binding detailed analysis report of human IgG-1, 2, 3

Ab	Chip	Affinity	Test item	Chi² (RU²)	Ka (1/Ms)	kdis (1/s)	KD (M)
Human IgG-1	ProA	Medium	Affinity	4.90e-02	1.39e+05	2.07e-03	1.49e-08
Human IgG-2	ProA	High	Affinity	3.41e-01	2.75e+04	3.59e-05	1.30e-09
Human IgG-3	ProA	Low	Kinetics	4.75	-	-	3.818e-07

Case 2: BLI v.s. SPR – IgG Affinity - BLI and SPR results are comparable for most antibody-antigen interactions

Most antigen-antibody interactions fall into the category of medium affinity samples, for which the detection results (KD) of BLI and SPR are nearly identical.

Rabbit IgG

Rabbit IgG

Mouse IgG
Case 3: BLI – Expression Supernatant – BLI is suitable for the affinity measurement of crude samples

The absence of a flow channel system in BLI simplifies system maintenance and enhances compatibility with crude samples, such as unpurified expression supernatants.