Monday, 30 May 2022: 08:40
West Meeting Room 121 (Vancouver Convention Center)
DNA self-assembled monolayer (SAM) on gold electrodes has been widely used for biosensing.1, 2 The sensor stability and performance determine the reliability of the test results in early disease detection and point-of-care use.3, 4 We have carefully examined the thermal stability of a mixed SAMs composed of a short alkylthiol and alkylthiol modified DNA prepared with electrodeposition vs. those prepared at OCP (Open Circuit Potential) on a single crystal gold bead electrode. The nature of these two types of SAMs were carefully studied in buffer after exposure to different temperatures using in-situ fluorescence microscopy and electrochemical measurements. The analysis showed that surfaces with hexagonal symmetry were thermally less stable than those with rectangular or square symmetry, suggesting that the crystallography of the gold substrate plays an important role in sensor stability and performance in addition to the DNA density.5
We also found that OCP deposition creates a surface with high DNA coverage (>1012 DNA/cm2) but with higher level of irreproducibility. Even though this kind of surface can be more thermally stable, it is not optimal for effective biosensing due to its high coverage.6 It also seems to be challenging to make DNA SAMs with both low coverage and high thermal stability by using current SAM preparation protocols (e.g., OCP). In this study, we show that electrodeposition can prepare DNA SAMs with both higher thermal stability than those made at OCP and with good control of low surface coverage. This study provides valuable insights on making high quality DNA SAMs with better stability and functionality and improved reproducibility.
References:
- Brittain, W. J.; Brandsetter, T.; Prucker, O.; Rühe, J. ACS Appl. Mater. Interfaces 2019, 11, 39397–39409.
- Civit, L.; Fragoso, A.; O’Sullivan, C. K. commun. 2010, 12, 1045–1048.
- Sheridan, C. Biotechnol. 2020.
- Panjan, P.; Virtanen, V.; Sesay, A. M. Talanta 2017, 170, 331–336.
- Ma, Tianxiao; Dan Bizzotto. Analytical Chemistry. 2021. 93 (48), 15973–15981.
- Peterson, A. W.; Heaton, R. J.; Georgiadis, R. M. Nucleic Acids Res. 2001, 29, 5163–5168.
