Electrochemically stable synthesis of DNA on gold electrodes based on pulsed DC voltage

Background DNA electrochemical synthesis, which utilizes electrochemical reactions to synthesize oligonucleotides, has gained attention for its potential in high-throughput applications. Gold, with its excellent electron conductivity, strong chemical stability, and process compatibility, is widely used for DNA electrochemical synthesis chips. Its ability to be chemically modified for initiating oligonucleotide synthesis makes it the material of choice. However, when gold electrodes are used as reaction substrates, metal layer delamination occurs due to the combined effects of voltage and electrolyte, which negatively affects DNA synthesis stability. The problem addressed in this study is the metal layer delamination that hinders reliable DNA synthesis. Results This study demonstrates that pulsed DC voltage effectively mitigates metal layer delamination on gold electrodes during DNA electrochemical synthesis. The delamination rate decreases significantly with higher pulse frequencies, from 54.61 % under continuous DC voltage to 17.98 % under pulsed DC voltage at the same voltage magnitude and a pulse frequency of 0.4 Hz. Notably, the electrochemical deprotection process causes minimal electrode damage even under short-term electrolytic action. Over longer operation times, pulsed DC voltage significantly extends electrode lifespan, with electrodes exhibiting enhanced stability and durability compared to continuous DC voltage. Fluorescence characterization of electrochemically synthesized DNA shows that synthesis quality is comparable under both pulsed and continuous DC voltages, provided the input voltage and operational time are consistent. This approach ensures the stable operation of gold electrodes, even in challenging chemical environments, and demonstrates clear advantages over traditional continuous DC voltage methods for preventing delamination. Significance and Novelty This work introduces the use of pulsed DC voltage to enhance electrode stability, effectively preventing metal layer delamination and ensuring high-quality DNA synthesis. By extending electrode lifespan and minimizing degradation, this method addresses key challenges in electrochemical DNA synthesis and supports the development of large-scale, high-throughput applications in the field.