Dye-doped silica nanoparticle labels/protein microarray for detection of protein biomarkers

Abstract

We report a dye-encapsulated silica nanoparticle as a label, with the advantages of high fluorescence intensity, photostability, and biocompatibility, in conjunction with microarray technology for sensitive immunoassay of a biomarker, Interleukin-6 (IL-6), on a microarray format. The tris (2,2'-bipyridyl)ruthenium (II)chloride hexahydrate (Rubpy) dye was incorporated into silica nanoparticles using a simple one-step microemulsion synthesis. In this synthesis process, Igepal CA520 was used as the surfactant, therefore, no requirement of cosolvent during the synthesis and the particle size was reduced comparing to the commonly used Triton surfactant system. The nanoparticles are uniform in size with a diameter of 50 nm. The microarray fluorescent immunoassay approach based on dye-doped silica nanoparticle labels has high sensitivity for practical applications with a limit of detection for IL-6 down to 0.1 ng mL −1 . The calibration curve is linear over the range from 0.1 ng mL −1 to 10 ng mL −1 . Furthermore, results illustrated that the assay is highly specific for IL-6 in the presence of range of cytokines or proteins. The RuDS dye-labeled nanoparticles in connection with protein microarrays show the promise for clinical diagnosis of biomarkers.

Fluorescent nanoparticles for chemical and biological sensing

“…The FRET hybrids can reach a very low LOD of goat antihuman IgG at 0.88 μg mL −1 . In conjunction with microarray technology, the dye-encapsulated silica NPs were also used for sensitive immunoassay of a biomarker, interleukin-6 [131].…”

FITC Labeled Silica Nanoparticles as Efficient Cell Tags: Uptake and Photostability Study in Endothelial Cells

“…Advancement of nanotechnology has drawn great interest in the area of biological imaging and drug delivery. Nanoscale materials are currently used as fluorescent probes in vitro and in vivo, drug carriers, contrast agents etc., thus aiding in pharmaceutical, therapeutic and diagnostic areas in the medical field [2][3][4][5][6]. Minimized particle size of nanoscale materials is critical for biological intracellular delivery as they are easily taken up by cells.…”

Rhodamine B doped silica nanoparticle labels for protein microarray detection

“…In this case, most of the organic fluorescent dyes have to be conjugated with hydrophilic or functional groups to avoid absorption and increase their solubility in water [9,10,12]. (Rubpy)-doped nanoparticles have been synthesized using this method [7,8]. The other is the Stöber method, in which the dye molecules are first chemically bound to reactive organosilicates to form a precursor, then hydrolyzed and co-condensed with TEOS in a mixture solution of ammonia and ethanol [13].…”

“…Rubpy (Tris(2,2c-bipyridyl)ruthenium(II) chloride hexahydrate) doped silica nanoparticles have been used in DNA and protein microarrays [7,8]. However, Rubpy is an inorganic dye with a low quantum yield and its excited wavelength does not match the current available solid scanner.…”