Novel synthesis approach for metal–biomolecule-framework–hexacyanoferrate composite nanofibers, besides developing a chiral sensing probe

Abstract

New stable composite nanofibers of copper hexacyanoferrate (CuHCF) were synthesized by a remarkable electrochemical design method. Cu(II)-L-aspartic acid nanofibers were used as a metal biomolecule framework (MBioF) for modifying a carbon paste electrode and electrochemical deposition of hexacyanoferrate from solution was performed to synthesize CuHCF nanofibers by cyclic voltammetry. This MBioF established a solid nanocompartment including copper ions for electrodepositing, which led to the in situ external template-free formation of CuHCF nanofibers. This preparation route combines the characteristics of one-dimensional nanofiber frameworks, the stereoselectivity of MBioFs, and the surprising features of the open-framework hexacynanometalates. This is a heterogeneous electrodeposition technique that represents a significant advancement in the synthesis of stable, self-template-assisted nanostructures of metal-hexacyanoferrates with tunable morphologies, moving beyond the conventional homogeneous reactions in solution phases. The redox peak of CuHCF nanofibers allows them to be used as a chiral probe due to the stereoselectivity of the Cu(II)-BioF nanofiber framework. Comprehensive characterization techniques are employed to elucidate the electrochemical synthesis process and the chiral interactions. In a subsequent application, the electrode modified with Cu(II)-L-aspartic acid nanofibers was used to recognize tyrosine enantiomers, considering a difference in the current signal of CuHCF during electrosynthesis with a linear range from 2.5 μM to 300.0 μM.