2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

pH Detections with Nano-cantilever-Based Biosensor System

S. Hur, H. Yoon, W.D. Kim
Korea Institute of Machnery & Materials, KR

pH, nano-cantilever, self-assembled monolayer

In this study, nano-cantilever based biosensor system is used to detect a biomolecule in a liquid. It is composed with an cantilevers array, liquid cell, a micro syringe pump, laser diode array, a position sensitive detector, data acquisition device, and data processing software. The probe cantilevers is functionalized with pH-sensitive MHA(mercaptohexadecanoic acid) at the first four cantilever, while the reference cantilevers are functionalized with HDT(hexadecanethiol). We prepare phosphate buffer solutions with different pH values and inject them into liquid cell at a regular time interval and at a regular injection speed. Then the functionalized cantilevers with the solutions of MHA or HDT produce the deflection of cantilever due to a binding between self assembled monolayer and probe molecules. A differential deflection, i.e. MHA-covered cantilever minus HDT-covered reference cantilever, was calculated to compensate for thermal drift. The differential deflection clearly increases with increasing pH. When the pH values of phosphate buffer solutions are high, it is shown that there are large variations in the deflection of cantilevers, whereas there are small variations for low pH value. The experiment results show that the cantilever array functionalized with MHA and HDT can detect pH value with good resolution and repeatability.

Nanotech 2008 Conference Program Abstract