Digital logic circuit based on two component molecular systems of BSA and salen

A new fluorescent molecular probe 1 was designed and constructed by combining bovine serum albumin (BSA) and N,N'-bis(salicylidene)ethylenediamine (salen). Stimulated by Zn²⁺, tris, or EDTAH₂Na₂, the distance between BSA and salen was regulated, which was accompanied by an obvious change in the fluorescence intensity at 350 or 445nm based on Förster resonance energy transfer. Moreover, based on the encoding binary digits in these inputs and outputs applying positive logic conventions, a monomolecular circuit integrating one OR, three NOT, and three YES gates, was successfully achieved.