Electrochemical sensing of L-histidine based on structure-switching aptamer and elongated tetrahexaheral gold nanocrystals

A sensitive aptasensor for detection of L-histidine based on switching structure of aptamer and elongated tetrahexaheral gold nanocrystals (ETHH Au NCs) is presented. The introduction of L-histidine induced self-cleavage of aptamer on the ETHH Au NCs / glassy carbon electrode (GCE) into the solution and the ferrocene (Fc) moiety approached the electrode surface and produced measurable electrochemical signals. With the enhancement effect of ETHH Au NCs, a linear electrical response was observed for concentrations ranging from 1 pM to 0.1 μM, a lower detection limit was 0.1 pM. The proposed approach exhibited excellent selectivity against other amino acids. Such an aptasensor provides a promising strategy for screening other amino acids and toxic ions at ultratrace levels on line.