Abstract
In this paper, we demonstrate the formation of uniformly distributed silver nanoparticles (NPs) regulated by gold NPs deposited in advance, and demonstrate their application to the enhancement of fluorescent signals. First, gold NPs were created by liquid-phase citrate reduction, and preferentially deposited onto surfaces chemically modified with 3-aminopropyl-trimethoxysilane (APTS). After the APTS was removed by oxygen plasma treatment, silver NPs were deposited onto the glass surface by a modified silver mirror reaction. Distribution of the silver NPs formed on the substrate was controlled by the reaction times of the gold and silver NP reduction processes. With gold NPs present, the silver NPs were more likely to deposit as isolated NPs than as aggregated NPs. This enabled the gold/silver NP substrates to achieve a significantly enhanced rhodamine-6G fluorescence, 8 times greater than that of a glass substrate on average, and greater than those of substrates with only silver or only gold NPs. The proposed gold and silver nanoparticle substrates are readily applicable to ultrasensitive bio/chemical detection technology.
Highlights
Metal nanoparticles (NPs) have been extensively studied for various uses, such as ultrasensitive bio/chemical detection using fluorescence enhancement[1,2,3,4,5,6] and/or surfaceenhanced Raman scattering.[7,8,9,10,11,12,13] Silver NPs are known to exhibit high enhancement whereas gold NPs have been widely used owing to their chemical stability and affinity to biochemical substances
Silver NPs can be formed by reducing silver nitrate.[23,24,25] A modified silver mirror reaction, in which dispersants are added to a conventional silver mirror reaction, can deposit silver NPs ~ 30 nm in diameter onto a glass substrate.[25]. This process can be combined with the spatial surface modification of the glass substrate by microcontact printing of a self-assembled monolayer (SAM), which enables siteselective deposition of silver NPs
3.1 Deposition of metal NPs Dense, uniform silver NPs were successfully formed on a glass substrate, with the most uniform silver NP layer formed at a reaction time of 80 s
Summary
Metal nanoparticles (NPs) have been extensively studied for various uses, such as ultrasensitive bio/chemical detection using fluorescence enhancement[1,2,3,4,5,6] and/or surfaceenhanced Raman scattering.[7,8,9,10,11,12,13] Silver NPs are known to exhibit high enhancement whereas gold NPs have been widely used owing to their chemical stability and affinity to biochemical substances They are highly efficient catalysts because of their extremely large surface/volume ratio.[14,15,16,17,18] These characteristics of NPs depend on the metal species and the nanoscale geometry. Previous reports suggest that multicomponent surface compositions produce synergistic effects and augment their activities
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
