Plasmonic Properties of Anchored Nanoparticles Fabricated by Reactive Ion Etching and Nanosphere Lithography

Aqueous environments pose unique challenges to the use of nanoparticle platforms for development of robust in vitro and in vivo sensors. A method is developed to anchor nanoparticles into a glass substrate by combining nanosphere lithography (NSL) and reactive ion etching (RIE) to create a mechanically durable sensing platform. The increased mechanical performance is attributed to the higher adhesion strength of NSL nanoparticles anchored in shallow nanowells formed by RIE. Using atomic force microscopy (AFM), anchored and conventional NSL nanoparticle arrays were subjected to increasing normal forces. The anchored nanoparticles were able to withstand normal forces 3 times greater (35.1 nN) compared to the conventional NSL nanoparticles (12.4 nN) prior to separation from the glass substrate. Superior adhesion in a constant flow aqueous environment is demonstrated by extinction measurements. After 1 h of 1.5 mL/min flow, extinction intensity decreased by 53% for bare and 13% for functionalized nanoparticle...