Tutorial: Saturation Transfer Difference NMR for Studying Small Molecules Interacting With Nanoparticles

Saturation transfer difference (STD) NMR is a robust, versatile technique for detecting small molecules binding to large receptors. In addition to identifying binding molecules in the presence of nonbinding molecules, the STD-NMR technique can be used to determine epitope maps and binding constants. In recent years, this technique has been applied to small molecules interacting with nanoparticles. In this tutorial, we introduce the technique of STD-NMR and how it can be used to gain information about small molecules interacting with nanoparticle surfaces. After describing the principle of the STD-NMR technique, we will explain how to best prepare the sample, set up the experiment, and analyze the resulting data when nanoparticles are involved. We will also present extensions to the STD-NMR technique, alternative approaches for when STD-NMR is not ideal, and future directions for the field.