A few-minute, simple, and affordable route to functionalized electrodes with DNA

A key challenge in developing DNA-based electrochemical sensors is the rapid and easy immobilization of DNA on different electrode surfaces. The current methods are often laborious and time-consuming. Here, we present a cost-effective and easy-to-perform method for efficiently functionalizing electrode surfaces with DNA in just a few minutes. Our strategy operates in two simple and rapid steps, regardless of the type of electrode, and avoids complicated and time-consuming procedures. The method uses phosphorothioate (PS) modification as an anchoring agent, which is a more cost-effective alternative to thiol (SH) modification, and eliminates the need for complex pretreatment processes. Additionally, a low-pH DNA loading method was used to quickly bind PS DNA to the gold surface without the need for surface-covering agents. We attributed the effect of low pH to the protonation of adenine (A), which leads to the formation of a parallel poly-A duplex (A motif) and facilitates vertical PS-DNA attachment to the electrode surface. Electrochemical techniques were used to confirm the vertical attachment of DNA to the electrode surface, and evaluation of the adsorption stability and hybridization efficiency confirmed the effectiveness of the method. The simplicity and efficiency of this method make it an ideal solution for researchers who require a fast and reliable method for DNA functionalization of electrode surfaces.