科研之友
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摘要
Targeted drugs have been increasingly recognized as effective agents against cancers because of their specificity. Kinetic label-free analysis is an essential tool to evaluate the affinity and reaction rate constants of drugs associated with their targets. Surface plasmon resonance (SPR) biosensors with real-time detection capability have been widely used as such a tool. The phase-type SPR technique based on Mach-Zehnder configuration has a high sensitivity because the measurement noise can be significantly reduced. In this study, we combine this technique with SPR imaging (SPRi), forming a phase SPRi biosensor to achieve multiplex detection. This phase SPRi biosensor, which features a 10(-5) RIU sensitivity and a 30 mu m x 20 mu m spatial resolution, is applied for the kinetic analysis of a typical targeted drug-cetuximab. After preliminary experiments to measure the antibody binding reaction on BSA, the affinity and reaction rate constants of cetuximab are evaluated for its target, namely the epidermal growth factor receptor. The measured equilibrium dissociation constant (K-D) is 4.20 (+/- 0.62) nM, and the measured dissociation constant (k(d)) is 1.76 (+/- 0.34) x 10(-3) S-1, which are both close to the values reported in literature.
