Gas-Phase Synthesis for Label-Free Biosensors: Zinc-Oxide Nanowires Functionalized with Gold Nanoparticles

E. Danielson, V. Dhamodharan, A. Porkovich, P. Kumar, N. Jian, Z. Ziadi, P. Grammatikopoulos, V. A. Sontakke, Y. Yokobayashi, M. Sowwan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Metal oxide semiconductor nanowires have important applications in label-free biosensing due to their ease of fabrication and ultralow detection limits. Typically, chemical functionalization of the oxide surface is necessary for specific biological analyte detection. We instead demonstrate the use of gas-phase synthesis of gold nanoparticles (Au NPs) to decorate zinc oxide nanowire (ZnO NW) devices for biosensing applications. Uniform ZnO NW devices were fabricated using a vapor-solid-liquid method in a chemical vapor deposition (CVD) furnace. Magnetron-sputtering of a Au target combined with a quadrupole mass filter for cluster size selection was used to deposit Au NPs on the ZnO NWs. Without additional functionalization, we electrically detect DNA binding on the nanowire at sub-nanomolar concentrations and visualize individual DNA strands using atomic force microscopy (AFM). By attaching a DNA aptamer for streptavidin to the biosensor, we detect both streptavidin and the complementary DNA strand at sub-nanomolar concentrations. Au NP decoration also enables sub-nanomolar DNA detection in passivated ZnO NWs that are resilient to dissolution in aqueous solutions. This novel method of biosensor functionalization can be applied to many semiconductor materials for highly sensitive and label-free detection of a wide range of biomolecules.

Original languageEnglish
Article number17370
JournalScientific Reports
Issue number1
StatePublished - 1 Dec 2019
Externally publishedYes


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