Second Harmonic Correlation Spectroscopy: A Method for Determining Surface Binding Kinetics and Thermodynamics

作者：Sly Krystal L; Mok Sze Wing; Conboy John C^*

来源：Analytical Chemistry, 2013, 85(17): 8429-8435.

DOI：10.1021/ac4018742

These studies describe the implementation of second harmonic correlation spectroscopy (SHCS) to measure the adsorption and desorption kinetics of molecular species associated with a surface. Specifically, the local fluctuations of the measured second harmonic (SH) signal were used to determine the binding kinetics and thermodynamics of (S)-(+)-1,1'-bi-2-napthol SBN intercalation into a 1,2-dioleoyl-sn-glycero-3-phosphocoline (DOPC) bilayer. In order to determine the adsorption and desorption rates, the SH signal was collected above saturation concentration at steady-state equilibrium as a function of time. The autocorrelated SH signal was then fit to a correlation model developed for molecules binding at a surface when there is no contribution from molecules in solution. The measured adsorption rate for SBN to DOPC was 2.7 +/- 0.2 X 10(3) s(-1) M-1 and the desorption rate was 9 +/- 4 x 10(-4) s(-1). The kinetic rates as well as the calculated equilibrium binding constant, 3.0 + 1.3 X 106 WI obtained from SHCS were compared with those obtained from a conventional binding isotherm and found to be statistically consistent. The primary advantage of using SHCS is both the absorption and desorption rates were determined in the same experiment using only a single bulk concentration of SBN. The results of these studies demonstrate that SHCS can be used to provide accurate kinetic and thermodynamic binding data in a label-free manner in lieu of conventional isotherm studies, especially where time and analyte are scarce.

• 出版日期2013-9-3