DNA-modified electrodes fabricated using copper-free click chemistry for enhanced protein detection

Langmuir. 2013 Dec 31;29(52):16141-9. doi: 10.1021/la403262v. Epub 2013 Dec 11.

Abstract

A method of DNA monolayer formation has been developed using copper-free click chemistry that yields enhanced surface homogeneity and enables variation in the amount of DNA assembled; extremely low-density DNA monolayers, with as little as 5% of the monolayer being DNA, have been formed. These DNA-modified electrodes (DMEs) were characterized visually, with AFM, and electrochemically, and were found to facilitate DNA-mediated reduction of a distally bound redox probe. These low-density monolayers were found to be more homogeneous than traditional thiol-modified DNA monolayers, with greater helix accessibility through an increased surface area-to-volume ratio. Protein binding efficiency of the transcriptional activator TATA-binding protein (TBP) was also investigated on these surfaces and compared to that on DNA monolayers formed with standard thiol-modified DNA. Our low-density monolayers were found to be extremely sensitive to TBP binding, with a signal decrease in excess of 75% for 150 nM protein. This protein was detectable at 4 nM, on the order of its dissociation constant, with our low-density monolayers. The improved DNA helix accessibility and sensitivity of our low-density DNA monolayers to TBP binding reflects the general utility of this method of DNA monolayer formation for DNA-based electrochemical sensor development.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Chemistry Techniques, Analytical / instrumentation*
  • Click Chemistry*
  • Copper / chemistry*
  • DNA / chemistry*
  • Electrodes*
  • Microscopy, Atomic Force
  • Models, Molecular
  • Molecular Structure
  • Proteins / analysis*
  • TATA-Box Binding Protein / chemistry

Substances

  • Proteins
  • TATA-Box Binding Protein
  • Copper
  • DNA