A label-free electrochemical DNA biosensor used a printed circuit board gold electrode (PCBGE) to detect SARS-CoV-2 without amplification

Abstract

The emergence of coronavirus disease 2019 (COVID-19) motivates continuous efforts to develop robust and accurate diagnostic tests to detect the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Detection of viral nucleic...

Editors’ Choice—Challenges and Opportunities for Developing Electrochemical Biosensors with Commercialization Potential in the Point-of-Care Diagnostics Market

“…65,71 ENIG uses a nickel layer on copper prior to gold deposition, while ENEPIG uses an intermediate palladium layer between nickel and gold to prevent long-term corrosion. 65,72 Hard gold plating offers a thicker layer of gold compared to ENIG to protect electrochemical chips from sliding wear, but ENIG plating offers more resistance to corrosion. 72,73 The thick layer of hard gold in high-wear areas of PCBs makes hard gold plating expensive.…”

“…65,72 Hard gold plating offers a thicker layer of gold compared to ENIG to protect electrochemical chips from sliding wear, but ENIG plating offers more resistance to corrosion. 72,73 The thick layer of hard gold in high-wear areas of PCBs makes hard gold plating expensive. 67 Therefore, the most commonly used method for fabricating electrochemical chips is ENIG.…”

“…67 Therefore, the most commonly used method for fabricating electrochemical chips is ENIG. 65,72,73 Immersion silver is directly electroplated from the electrolyte solution onto the copper layer, and lacks a nickel layer, making it weaker than immersion gold and requiring more care for long-term storage. 68 Industrial plating processes that use ENIG, ENEPIG, and hard gold introduce organic and inorganic impurities such as watersoluble and rosin-based flux residues, 74 copper traces, 75 and in rare cases, nickel 76 on electrodes, which could interfere with functionalization and consequently, the electroanalytical performance of biosensors manufactured using PCB technology.…”

“…Because of its scalable and inexpensive production cost, PCB electrodes are becoming key alternatives to SPEs and have been employed for POC detection of various target analytes including infectious agents, 72,79 disease biomarkers, 65 and small molecules. 80,81 Nevertheless, the oxidation of copper in the tracks of PCB electrodes introduces a challenge for electrochemical biosensors as it interferes with their analytical performance, hindering their wider acceptance.…”