Conformational tuning of sensing Langmuir-Blodgett membranes for selective determination of metal ions, anions, and molecular fragments

In this work, we describe a novel approach to prepare ionophore-based Langmuir-Blodgett (LB) sensors with desirable analytical characteristics via fine tuning of macrocycle conformation during the assembly of the membrane. In this context, two related types of LB sensors of dicetyl cyclen and its complex with Zn²⁺ were constructed. The multi-use mass-sensitive and electrochemical LB-multilayer sensors of DCC were used for selective and accurate detection of divalent copper traces (down to 10^-9M) in aqueous solution, containing other similar metal ions (Zn²⁺ and Ni²⁺). The SPR-based imide recognition modeled with uracil binding and the phosphate recognition were investigated with SAM-supported LB monolayers of zinc(II)-dycetyl cyclen complexes. Controlled steric constraints imposed on Zn(II)-DCC structure upon membrane formation resulted in exceptional selectivity toward inorganic HPO₄^2- (at least down to 10^-8M of anions).