Hydrogen bonding involves the attraction between a hydrogen atom, which is covalently bonded to an electronegative atom, and another electronegative atom. At the nanoscale, hydrogen bonds significantly affect the interaction between molecules and the stability of complex nanostructures. This is particularly important in biological systems, where hydrogen bonds are critical for the structure and function of proteins and DNA. Understanding hydrogen bonding at the nanoscale aids in the design of biocompatible materials and drug delivery systems.