An electrochemical and surface plasmon resonance study of adsorption actions of DNA by Escherichia coli

• A polypeptide RGD immobilization scheme for bacterial cells is described.
• Binding process between E. coli and hsDNA investigated by electrochemical and SPR.
• The two methods can be used to detect the DNA binding on microorganism surface.

In this work, we proposed an immobilization scheme targeting Escherichia coli bacterial cells onto gold surface utilizing polypeptide RGD's binding specificity to gold particles. Adsorption kinetics of extracellular Herring Sperm DNA on E. coli was then studied using electrochemical methods along with surface plasmon resonance spectroscopy through this immobilization scheme. The adsorption equilibrium constants of DNA adsorbing to E. coli from electrochemical method and surface plasmon resonance spectroscopy, were (5.596 ± 0.462) × 105 L mol−1 and (1.24 ± 0.361) × 105 L mol−1, accordingly. Importantly, this is the first study that used an electrochemical method to express the adsorptive action of DNA by E. coli.

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