title: Measurement of small molecule binding kinetics on a protein microarray by plasmonic-based electrochemical impedance imaging.
abstract: We report on a quantitative study of small molecule binding kinetics on protein microarrays with plasmonic-based electrochemical impedance microscopy (P-EIM). P-EIM measures electrical impedance optically with high spatial resolution by converting a surface charge change to a surface plasmon resonance (SPR) image intensity change, and the signal is not scaled to the mass of the analyte. Using P-EIM, we measured binding kinetics and affinity between small molecule drugs (imatinib and SB202190) and their target proteins (kinases Abl1 and p38-α). The measured affinity values are consistent with reported values measured by an indirect competitive binding assay. We also found that SB202190 has weak bindings to ABL1 with KD > 10 μM, which is not reported in the literature. Furthermore, we found that P-EIM is less prone to nonspecific binding, a long-standing issue in SPR. Our results show that P-EIM is a novel method for high-throughput measurement of small molecule binding kinetics and affinity, which is critical to the understanding of small molecules in biological systems and discovery of small molecule drugs.
authors.affiliation: Center for Bioelectronics and Biosensors and §Center for Personalized Medicine, Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Liang
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Wang
authors.forename: Fernanda
authors.initials: F
authors.lastname: Festa
authors.forename: Peter
authors.initials: P
authors.lastname: Wiktor
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Mitchell
authors.initials: M
authors.lastname: Magee
authors.forename: Joshua
authors.initials: J
authors.lastname: LaBaer
authors.forename: Nongjian
authors.initials: N
authors.lastname: Tao
mesh_terms: D001549:Benzamides / Q000737:chemistry*; D017097:Electric Impedance; D006801:Humans; D000068877:Imatinib Mesylate; D007093:Imidazoles / Q000737:chemistry*; D007700:Kinetics; D037601:Mannose-Binding Lectin / Q000737:chemistry*; D048308:Mitogen-Activated Protein Kinase 14 / Q000737:chemistry*; D057054:Molecular Imaging / Q000295:instrumentation / Q000379:methods*; D010879:Piperazines / Q000737:chemistry*; D040081:Protein Array Analysis; D011485:Protein Binding; D016315:Proto-Oncogene Proteins c-abl / Q000737:chemistry*; D019009:Proto-Oncogene Proteins c-kit / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D020349:Surface Plasmon Resonance
chemical_list: D001549:Benzamides; D007093:Imidazoles; D037601:Mannose-Binding Lectin; D010879:Piperazines; D011725:Pyridines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit; D016315:Proto-Oncogene Proteins c-abl; D048308:Mitogen-Activated Protein Kinase 14; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole