Molecular recognition and biological application of modified β-cyclodextrins

The molecular recognition based on cyclodextrins (CDs) has become a focus of interest in modern supramolecular chemistry. CDs are known to encapsulate various ions and organic/inorganic molecules in their hydrophobic cavities and form stable inclusion complexes through cooperative noncovalent interactions. During the past few decades, a large variety of modified CDs have been elaborately designed and synthesized, which significantly promotes our molecular-level understanding of the structure–function relationship in many supramolecular systems. Through the accurate analysis on the molecular binding behaviors, one can create a library of CD-based nanoassemblies with controlled physicochemical properties. In this review, we will focus on the stability constant-directed molecular recognition and the biological activities of β-CDs toward some representative bioactive substrates, including metal ions, steroids, porphyrins, amino acids and oligopeptides, as well as drug molecules, with the final goal of promoting their practical applications in the biomedical field.