title: Plasmonic imaging of protein interactions with single bacterial cells.
abstract: Quantifying the interactions of bacteria with external ligands is fundamental to the understanding of pathogenesis, antibiotic resistance, immune evasion, and mechanism of antimicrobial action. Due to inherent cell-to-cell heterogeneity in a microbial population, each bacterium interacts differently with its environment. This large variability is washed out in bulk assays, and there is a need of techniques that can quantify interactions of bacteria with ligands at the single bacterium level. In this work, we present a label-free and real-time plasmonic imaging technique to measure the binding kinetics of ligand interactions with single bacteria, and perform statistical analysis of the heterogeneity. Using the technique, we have studied interactions of antibodies with single Escherichia coli O157:H7 cells and demonstrated a capability of determining the binding kinetic constants of single live bacteria with ligands, and quantify heterogeneity in a microbial population.
authors: Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
authors: Karan
authors: K
authors: Syal
authors: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors: Wei
authors: W
authors: Wang
authors: Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA.
authors: Xiaonan
authors: X
authors: Shan
authors: Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors: Shaopeng
authors: S
authors: Wang
authors: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China. Electronic address: hychen@nju.edu.cn.
authors: Hong-Yuan
authors: HY
authors: Chen
authors: Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China; School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA. Electronic address: njtao@asu.edu.
authors: Nongjian
authors: N
authors: Tao
mesh_terms: D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D019453:Escherichia coli O157 / Q000737:chemistry / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D025941:Protein Interaction Mapping / Q000379:methods*; D059010:Single-Cell Analysis / Q000379:methods*; D020349:Surface Plasmon Resonance
chemical_list: D000906:Antibodies; D029968:Escherichia coli Proteins; D008024:Ligands
keywords: Analytical chemistry; Antigen–antibody kinetics; Bacterial population heterogeneity; Biosensors; Single microbial cell; Surface plasmon resonance microscopy