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Adsorption of DNA Oligonucleotides by Titanium Dioxide Nanoparticles

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Liu_Juewen(3)-stmt.pdf (783.89 KB)

Date

2014-01-28

Authors

Zhang, Xu
Wang, Feng
Liu, Biwu
Kelly, Erin Y.
Servos, Mark R.
Liu, Juewen

Journal Title

Journal ISSN

Volume Title

Publisher

American Chemical Society

Abstract

Titanium dioxide (TiO2) or titania shows great promise in detoxification and drug delivery. To reach its full potential, it is important to interface TiO2 with biomolecules to harness their molecular recognition function. To this end, DNA attachment is an important topic. Previous work has mainly focused on long double-stranded DNA or single nucleotides. For biosensor development and targeted drug delivery, it is more important to use single-stranded oligonucleotides. Herein, the interaction between fluorescently labeled oligonucleotides and TiO2 nanoparticles is reported. The point of zero charge (PZC) of TiO2 is around 6 in water or acetate buffer; therefore, the particles are positively charged at lower pH. However, if in phosphate or citrate buffer, the particles are negatively charged, even at pH ∼2, suggesting strong adsorption of buffer anions. DNA adsorption takes place mainly via the phosphate backbone, although the bases might also have moderate contributions. Peptide nucleic acids (PNAs) with an amide backbone cannot be adsorbed. DNA adsorption is strongly affected by inorganic anions, where phosphate and citrate can strongly inhibit DNA adsorption. DNA adsorption is promoted by adding salt or lowering pH. DNA adsorption is accompanied with fluorescence quenching, and double-stranded DNA showed reduced quenching, allowing for the detection of DNA using TiO2 nanoparticles.

Description

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see http://dx.doi.org/10.1021/la404633p

Keywords

adsorption, DNA, oligonucleotides, Titanium Dioxide, nanoparticle, quenching

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Citation

URI

http://dx.doi.org/10.1021/la404633p
 http://hdl.handle.net/10012/11359

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Waterloo Research
Chemistry
Waterloo Institute for Nanotechnology