Plasmonic Properties of the Multispot Copper-Capped Nanoparticle Array Chip and Its Application to Optical Biosensors for Pathogen Detection of Multiplex DNAs

Abstract

A localized surface plasmon resonance (LSPR)-based optical biosensor in connection with a multispot copper-capped nanoparticle array (MC-NPA) chip was proposed and developed. The copper (Cu) films, used as a shell, formed a "cap-like" layer on the top of the silica nanoparticles, used as a core, in an orderly fashion, to form the surface called a "Cu-capped nanoparticle array chip". The plasmonic properties of this nanostructure type were initially investigated while controlling the shell thickness of the deposited Cu. Also, we quantified the sensitivity of MC-NPA chip to changes in bulk refractive index (RI). As a result of its LSPR properties, the MC-NPA chip displayed a sensitivity of 67.8 nm per RI unit, and the wavelength shift of the LSPR spectrum peak was sensitive to the RI of the surrounding bulk medium, such as the biomolecular layers. Using MC-NPA chips, multiplex sensing of target DNAs from reference bacteria and clinical samples was possible in a quantitative manner with a detection limit of 10 fM (50 zmol). The optical biosensor developed in this study represents a unique approach to performing LSPR that utilizes a simple and cost-effective optical setup with disposable chips.

Strategies for enhancing the sensitivity of plasmonic nanosensors

“…While plasmonic nanosensors are almost exclusively made of gold or silver, LSPR sensing applications of other metal and/or metal oxide nanocomposites, e.g., zinc oxide [78][79][80], aluminium [81][82][83][84][85][86][87] and copper [88][89][90][91][92][93][94][95][96], have also been investigated. However, the non-noble metals are susceptible to corrosion in aqueous environments and oxidation in air, both of which significantly diminish refractive index sensitivity [4].…”

Recent Advancements in Nanobioassays and Nanobiosensors for Foodborne Pathogenic Bacteria Detection

“…LSPR detection of seven pathogenic bacteria, including foodborne Salmonella, S. aureus, and Enterococcus faecalis, was demonstrated on copper-capped nanoparticle array chips through probe-target DNA hybridization. The LOD was 10 fM after the PCR, with stable, quantitative, and reproducible signal and high specificity (57).…”

Preparation and study of concentrated hydrosols of copper nanoparticles using of weak reducing agents

“…A number of reports have been published on preparation of copper nanoparticles using weak reducing agents [13][14][15][16][17][18]; however, the issue of the process optimization has been rarely touched upon, and the data are often contradictory. For example, the products obtained under similar conditions are reported as copper, copper oxide, or mixed nanoparticles.…”