Evaluating the Thickness of Multivalent Glycopolymer Brushes for Lectin Binding

Electrochemical impedance spectroscopy (EIS) is applied for investigating binding of lectins to multivalent glycopolymer brushes grafted from interdigital gold microelectrodes. By variation of the measuring frequency, EIS allows simultaneous analysis of binding at different subnanometer distances from the sensor surfaces. In this way, the binding dynamics along the brushes are quantified, giving an idea about the motion of the lectin through the brush layer. Two different brush lengths are investigated, revealing distinct dynamics of lectin binding due to changing topology of the brushes. Moreover, very low K-D values in the nanomolar range are obtained. This unique platform may be used as sophisticated biosensor for detailed investigation of high-affinity protein binding to polymer layers.