Formation of ssDNA Brushes With Controlled Spacing on Gold Substrates Using Block-Oligonucleotides

Published

October 12, 2021

Author(s)

A Opdahl, D Y. Petrovykh, H Y. Kimura-Suda, L J. Whitman, Michael J. Tarlov

Abstract

Block-oligonucleotides, d(Tm-An), with specific thymine (dT) and adenine (dA) sequence lengths, m and n, and no additional chemical modifications, were adsorbed on gold substrates from aqueous buffer solution and characterized by FTIR and by XPS. The FTIR and XPS experimental results support a model where the d(An) blocks preferentially adsorb on the gold substrate and the d(Tm) blocks extend away from the substrate. The underlying principal of this L-shaped conformation is the previously reported observation that (dA) oligonucleotides have a higher affinity than (dT) oligonucleotides for adsorbing on gold substrates (Kimura-Suda, H.; Petrovykh, D. Y.; Tarlov, M. J.; Whitman, L. J.; J. Am. Chem. Soc.; 2003; 125(30); 9014-9015). For a range of short d(Tm-An) compositions, the overall surface density of dA nucleotides adsorbed on the gold is approximately independent of the d(An) block length, such that the surface density of the d(An) blocks decreases as their length increases. For those compositions, the d(Tm-An) oligonucleotides with longer d(An) blocks have lower densities of d(Tm) brush strands in the adsorbed layer. For longer oligonucleotides, increasing the percentage of dT in the strand is observed to decrease the immobilization efficiency.

Citation

Journal of the American Chemical Society

Pub Type

Journals

Keywords

biosensors, DNA, FTIR, gold, polyelectrolyte brushes, self assembled monolayers (SAMs), XPS

Citation

Opdahl, A. , Petrovykh, D. , Kimura-Suda, H. , Whitman, L. and Tarlov, M. (2021), Formation of ssDNA Brushes With Controlled Spacing on Gold Substrates Using Block-Oligonucleotides, Journal of the American Chemical Society (Accessed October 6, 2024)