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‘Overloading’ fluorescent silica nanoparticles with dyes to improve biosensor performance

Moore, Colin, Giovannini, Giorgia, Kunc, Filip, Hall, Andrew J., Gubala, Vladimir (2017) ‘Overloading’ fluorescent silica nanoparticles with dyes to improve biosensor performance. Journal of Materials Chemistry B, 2017 (5). pp. 5564-5572. ISSN 2050-750X. (doi:10.1039/C7TB01284E) (KAR id:62152)

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Using dye-doped silica nanoparticles (DSNP) as reporter probes, we describe a simple method of enhancing fluorescent signal and the extension of the detectable target concentration range in a proof-of-concept ‘dissolution immunoassay’. DSNPs were intentionally ‘overloaded’ with 3% (w/w) FITC such that the high concentration of dye inside the NP core induced self-quenching. Despite exhibiting reduced brightness, the ‘overloaded’ DSNPs were then functionalized with anti-human IgG and were subsequently used to detect human IgG, a model biomarker, in whole serum. Following human IgG recognition, the ‘overloaded’ DSNPs were dissolved using pH10.6, 0.1M sodium carbonate-bicarbonate buffer. The large quantity of FITC inside the NP core was consequently released into solution, thus liberating the dyes from self-quenching, and led to a large increase in fluorecein emission intensity. This effect was further enhanced when coupled with FITC’s increased quantum yield in basic conditions. The overall result was a 12-fold enhancement in fluorescent signal intensity and an 11-fold improvement in signal-to-noise ratio after a dissolution time of 60 mins. In the assay setup presented, the net signal-to-noise ratio for ‘overloaded’ DSNPs was up to 9 times greater following degradation compared to traditionally used 1% (w/w) ‘optimal’ dye-loaded DSNPs. Crucially, this ‘dissolution assay’ strategy using ‘overloaded’ DSNPs could confidently detect human IgG at a 10-fold lower concentration than traditionally used ‘optimal’ DSNPs.

Item Type: Article
DOI/Identification number: 10.1039/C7TB01284E
Divisions: Divisions > Division of Natural Sciences > Medway School of Pharmacy
Depositing User: Andrew Hall
Date Deposited: 27 Jun 2017 10:53 UTC
Last Modified: 08 Dec 2022 21:26 UTC
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