Nanogel Characterization and Thermal Analysis

Proton nuclear magnetic resonance (NMR) spectra were recorded on a Varian Mercury-400 NMR spectrometer (400 MHz) in D₂O using tetramethylsilane (TMS) as a reference. The particle sizes and zeta potentials of complexes at weight ratio 10 were determined using a commercial laser light scattering instrument (Malvern ZEN3690, Malvern Panalytical Ltd., Cambridge, UK) at room temperature. The hydrodynamic diameter of nanogels was measured from 25–80 °C with 2 °C intervals [45 (link)]. The morphologies of nanogels were characterized through atomic force microscopy (AFM) imaging (Dimension 3100 Nanoscope V, Veeco, Plainview, NY, USA). DNP cantilevers (k = 0.24 N/m) were operated in the air using contact mode.