Interfacial Structure and Transformation of Guanine-Rich Oligonucleotides on Solid Supported Lipid Bilayer Investigated by Sum Frequency Generation Vibrational Spectroscopy

Abstract

Lipid membrane-anchored guanine-rich oligonucleotides with non-Watson–Crick structures can perform structure transformation in a controllable and reversible manner upon the external stimuli. Elucidating the mechanisms of their interaction and transformation is the key to understand medical applicability and functioning feasibility of these oligonucleotides. In this study, the molecular structure and interfacial transformation kinetics of guanine-rich oligonucleotides at model cell membrane were investigated by sum frequency generation vibrational spectroscopy (SFG-VS) in real time and <i>in situ</i>. The conformations of oligonucleotides are obtained by analyzing the SFG spectra in the “fingerprint” region. The results indicate that the electrostatic interaction and hydrophobic interaction are both important to the interfacial adsorption and transformation of oligonucleotides. The tilt angles of oligonucleotides with different conformations were also calculated. Molecular insights into interfacial oligonucleotides will help researchers to control the oligonucleotide–lipid membrane interactions in a desired manner and improve the reproductivity, stability, and reversibility of oligonucleotide-based applications