A probing system using Au nano-dot for measuring the single protein-carbohydrate bonding force

A new probing system is proposed and developed to detect and analyze the interaction of bio materials at the molecular level. Unlike the conventional technique, when the probing method is used, the substrate is treated so that a single molecule is likely to attach to an isolated area. The substrate is micro-machined to have an Au nano-dot array with various sizes from 20 nm to 70 nm in diameter and about 20 nm in height considering the size of target protein molecules. In addition, a probing instrument adopting the working principle of AFM is manufactured to measure the protein-carbohydrate interaction force with the patterned substrate and a conventionally functionalized AFM probe. The unbinding force between a single protein (vibrio cholera toxin B subunit) and a carbohydrate (ganglioside GM1 pentasaccharide) is selected to be the objective of measurement. The developed probing method and instrument are evaluated by detecting and measuring the target molecular interaction.