Immobilization of DNA-Au nanoparticles on aminosilane-functionalized aluminum nitride epitaxial films for surface acoustic wave sensing

Abstract

A generic method for immobilization of gold nanoparticle bioconjugates onto aluminum nitride (AlN) surfaces using aminosilane molecules as cross-linkers is demonstrated for surface acoustic wave (SAW) sensor applications. Electrostatic interaction between positively charged surface amine groups and negatively charged DNA-Au nanoparticle conjugates allows the self-assembly of a probe nanoparticle monolayer onto functionalized AlN surfaces under physiological conditions. Both 10 and 20 nm Au nanoparticles bound with thiolated oligonucleotides were employed in the detection scheme. We show that Au nanoparticles can play multiple roles in SAW sensing for probe immobilization, signal amplification, and labeling.