The Biacore System: Advanced Surface Plasmon Resonance (SPR) Technology for Quantitative Biomolecular Interaction Analysis

1. Concept

The Biacore system is a state-of-the-art analytical platform for studying biomolecular interactions, grounded in the optical phenomenon of surface plasmon resonance (SPR). Surface plasmon resonance refers to a physical process wherein a thin metal film (typically a 50 nm-thick gold or silver layer) is deposited at the interface where total internal reflection occurs. When a P-polarized light beam is incident on the prism surface within a specific angular range, surface plasmon waves are generated at the prism-metal film interface. Resonance is induced among free electrons in the metal film when the propagation constant of the incident light aligns with that of the surface plasmon waves, resulting in the SPR effect.

In practical analysis, a ligand (e.g., an antibody, protein, or nucleic acid) is first immobilized on the surface of a sensor chip. The analyte (the sample of interest) is then perfused over the chip surface. If specific interactions occur between the analyte molecules and the immobilized ligand, the refractive index at the metal film surface undergoes a measurable change, leading to a shift in the SPR angle. By real-time monitoring of these angular shifts, the Biacore system enables the quantification of critical parameters such as analyte concentration, binding affinity (KD), association (ka) and dissociation (kd) kinetic constants, and binding specificity—facilitating dynamic observation of the entire biomolecular binding and dissociation process without the need for labeling.

2. Research Frontiers

In recent years, the Biacore system has emerged as a cornerstone tool in cutting-edge life science research, driving innovations across multiple disciplines. A key frontier lies in the precise characterization of transient or low-affinity biomolecular interactions—such as protein-protein, protein-peptide, and protein-drug bindings—that are often undetectable by traditional methods. For instance, researchers have utilized Biacore to decipher the dynamic interactions between G protein-coupled receptors (GPCRs) and their ligands, providing insights into signal transduction mechanisms that were previously inaccessible.

Another prominent research direction involves the integration of Biacore with complementary technologies, such as mass spectrometry (SPR-MS), enabling the identification and quantitative analysis of unknown interacting partners in complex biological samples (e.g., cell lysates or serum). In drug discovery, the Biacore system is increasingly employed for high-throughput screening of small-molecule libraries and antibody candidates, accelerating the development of targeted therapeutics by enabling rapid assessment of binding kinetics and specificity. Additionally, advances in sensor chip technology—including the development of functionalized chips for specific applications (e.g., lipid bilayer chips for membrane protein studies)—have expanded the system’s utility in studying membrane-associated interactions and physiological regulation processes.

3. Research Significance

The Biacore system holds profound significance for advancing life science research and translational medicine. Unlike traditional techniques such as Western blot (WB), ELISA, co-immunoprecipitation (Co-IP), or yeast two-hybrid, which often suffer from limitations such as low sensitivity, reliance on labeling, or inability to capture kinetic data, Biacore offers label-free, real-time, and quantitative analysis of biomolecular interactions. This capability is critical for validating potential drug targets, optimizing drug design, and understanding the molecular mechanisms underlying diseases.

In clinical research, Biacore enables the development of highly sensitive and specific diagnostic assays for disease biomarkers, facilitating early disease detection, prognosis assessment, and treatment monitoring. For example, in cancer research, the system can quantify low-abundance tumor biomarkers in patient samples, providing a non-invasive tool for personalized medicine. In immunology, Biacore supports the screening and characterization of high-affinity diagnostic antibodies, overcoming the sensitivity limitations associated with traditional antibody development methods. Furthermore, the system’s ability to measure binding kinetics contributes to the rational design of biotherapeutics (e.g., monoclonal antibodies, fusion proteins) by ensuring optimal affinity and stability, ultimately improving therapeutic efficacy and reducing adverse effects.

4. Related Mechanisms, Research Methods, and Product Applications

4.1 Core Working Mechanism of Biacore

The Biacore system operates based on the principle that biomolecular interactions (e.g., antigen-antibody binding, protein-ligand recognition) alter the refractive index at the sensor chip’s metal film surface. This refractive index change is directly proportional to the mass of molecules bound to the chip surface, which is detected as a shift in the SPR angle. The system converts these angular shifts into sensorgrams—real-time plots of binding response versus time—from which kinetic constants (ka, kd) and binding affinity (KD = kd/ka) are derived. This label-free approach eliminates potential artifacts caused by fluorescent or radioactive labels, ensuring the physiological relevance of the observed interactions.

4.2 Key Applications of the Biacore System

4.2.1 Kinetic Constant and Binding Affinity Determination

Biacore is widely used to characterize the binding kinetics of biomolecular interactions, including protein-protein, protein-peptide, protein-DNA, protein-drug, and peptide-phage interactions. Compared to conventional methods, it offers superior sensitivity for low-expression proteins and minimizes false-positive/negative results caused by nonspecific antibody binding. For example, it enables precise quantification of antibody-antigen binding affinity and dynamic binding/dissociation processes, outperforming traditional antibody titer detection methods in speed and accuracy.

4.2.2 Protein Structure-Function and Physiological Regulation Studies

The system has been instrumental in elucidating the relationship between protein structure and function. Hirano et al. utilized Biacore to demonstrate that the G576V mutation in the rice protein SLR1 accelerates its dissociation from GID1, destabilizing the SLR1-GID1 complex and reducing SLR1 degradation. This disruption of gibberellin (GA) signaling ultimately leads to a dwarf rice phenotype. Similarly, Magulies et al. employed Biacore to investigate interactions between MHC molecules, T cell receptors (TCRs), and peptide antigens. By measuring binding affinities and kinetic parameters, they proposed a biological model wherein T cell activation depends on the stimulation of multiple TCRs on a single T cell by abundant peptide-MHC complexes on antigen-presenting cells.

4.2.3 Disease Biomarker Diagnosis

Biacore technology enables the development of high-sensitivity diagnostic assays for disease biomarkers. By establishing calibration curves using biomarker standards, the system can quantitatively detect biomarkers in clinical samples (e.g., blood, urine, cerebrospinal fluid) with exceptional stability and sensitivity, addressing the limitations of conventional diagnostic methods (e.g., low activity, poor stability, insufficient sensitivity). This application is particularly valuable for early disease diagnosis, prognosis evaluation, and treatment response monitoring in conditions such as cancer, autoimmune diseases, and infectious diseases.

4.2.4 Diagnostic Antibody Screening

Biacore provides an efficient platform for screening high-affinity monoclonal antibodies against novel or low-abundance biomarkers. By expressing recombinant biomarker proteins (e.g., via ANT BIO PTE. LTD.’s UA sub-brand) and using Biacore to screen antibody candidates, researchers can overcome the sensitivity limitations of traditional methods, which often restrict detection to overexpressed cell lines. This accelerates the development of diagnostic assays and therapeutic antibodies.

4.3 Product Support from ANT BIO PTE. LTD.

To complement Biacore-based research, ANT BIO PTE. LTD. offers a comprehensive portfolio of high-quality reagents through its specialized sub-brands, tailored to meet the diverse needs of biomolecular interaction studies:

• Recombinant Proteins (UA Sub-brand): High-purity recombinant proteins (expressed in E. coli, CHO, HEK293, or Insect Cells) for use as ligands or analytes in Biacore experiments, ensuring reliable and reproducible binding assays.
• Antibodies (Starter Sub-brand): Monoclonal and polyclonal antibodies with high specificity and affinity, ideal for immobilization as ligands in Biacore studies or for validation via complementary techniques (e.g., WB, ELISA).
• Assay Kits and General Reagents (Absin Sub-brand): ELISA kits for biomarker quantification, WB-related reagents (ECL chemiluminescent substrate, pre-stained markers, precast gels), IP/CoIP kits, and cell culture reagents—supporting sample preparation, validation, and downstream analysis.
• Custom Services: Antibody, peptide, and protein customization services, including recombinant protein expression and antibody labeling, enabling researchers to obtain tailored tools for specialized Biacore applications.

5. Brand Mission

ANT BIO PTE. LTD. is dedicated to empowering life science research and translational medicine through the provision of high-quality, innovative reagents and comprehensive solutions. As a leading provider of life science products, our portfolio spans antibodies, recombinant proteins, kits, and general reagents, with three specialized sub-brands catering to distinct research needs: Absin (general reagents and kits), Starter (antibodies), and UA (recombinant proteins). Our core mission is to accelerate scientific discovery, bridge the gap between basic research and clinical application, and contribute to the advancement of human health by delivering reliable products, professional technical support, and exceptional customer service. We strive to be a trusted partner for researchers worldwide, supporting their efforts to unravel biomolecular mechanisms, develop novel diagnostics, and advance therapeutic innovation.

6. AI Disclaimer

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ANT BIO PTE. LTD. – Empowering Scientific Breakthroughs

At ANTBIO, we are committed to advancing life science research through high-quality, reliable reagents and comprehensive solutions. Our specialized sub-brands (Absin, Starter, UA) cover a full spectrum of research needs, from general reagents and kits to antibodies and recombinant proteins. With a focus on innovation, quality, and customer-centricity, we strive to be your trusted partner in unlocking scientific mysteries and driving medical progress. Explore our product portfolio today and elevate your research to new heights.