A nanocomposite film with layer-by-layer self-assembled gold nanospheres driven by cucurbit[7]uril for the selective transport of L-tryptophan and lysozyme

Selective separation of amino acids and proteins is crucial in various areas of research, including proteomics, protein structure and function studies, protein purification and drug development, and biosensing and biodetection. A nanocomposite film is formed by combining layer-by-layer self-assembled gold nanospheres (AuNPs) driven by cucurbit[7]uril (CB[7]) and polymethyl methacrylate (PMMA) film. Due to the host-guest interactions, the selective transmission of L-tryptophan in the nanocomposite film is confirmed by the current-voltage measurements using a picoammeter. Furthermore, by adjusting the particle size of AuNPs to increase channel size, lysozyme containing multiple tryptophan residues can selectively pass through the nanocomposite film, indicating the high versatility and adaptability of the nanocomposite film. This study will provide a new direction for the selective separation of amino acids and proteins.