Gold Nanoparticle-Quantum Dot Fluorescent Nanohybrid: Application for Localized Surface Plasmon Resonance-induced Molecular Beacon Ultrasensitive DNA DetectionReport as inadecuate




Gold Nanoparticle-Quantum Dot Fluorescent Nanohybrid: Application for Localized Surface Plasmon Resonance-induced Molecular Beacon Ultrasensitive DNA Detection - Download this document for free, or read online. Document in PDF available to download.

Nanoscale Research Letters

, 11:523

First Online: 25 November 2016Received: 29 September 2016Accepted: 21 November 2016

Abstract

In biosensor design, localized surface plasmon resonance LSPR-induced signal from gold nanoparticle AuNP-conjugated reporter can produce highly sensitive nanohybrid systems. In order to retain the physicochemical properties of AuNPs upon conjugation, high colloidal stability in aqueous solution is needed. In this work, the colloidal stability with respect to the zeta potential ZP of four negatively charged thiol-functionalized AuNPs, thioglycolic TGA-AuNPs, 3-mercaptopropionic acid MPA-AuNPs, l-cysteine-AuNPs and l-glutathione GSH-AuNPs, and a cationic cyteamine-capped AuNPs was studied at various pHs, ionic strength, and NP concentration. A strong dependence of the ZP charge on the nanoparticle NP concentration was observed. High colloidal stability was exhibited between pH 3 and 9 for the negatively charged AuNPs and between pH 3 and 7 for the cationic AuNPs. With respect to the ionic strength, high colloidal stability was exhibited at ≤10 μM for TGA-AuNPs, l-cysteine-AuNPs, and GSH-AuNPs, whereas ≤10 μM is recommended for MPA-AuNPs. For the cationic AuNPs, very low ionic strength of ≤10 μM is recommended due to deprotonation at higher concentration. GSH-AuNPs were thereafter bonded to SiO2-functionalized alloyed CdZnSeS-ZnSe1.0S1.3 quantum dots SiO2-Qdots to form a plasmon-enhanced AuNP-SiO2-Qdots fluorescent nanohybrid. The AuNP-SiO2-Qdots conjugate was afterward conjugated to a molecular beacon MB, thus forming an ultrasensitive LSPR-induced SiO2-Qdots-MB biosensor probe that detected a perfect nucleotide DNA sequence at a concentration as low as 10 fg-mL. The limit of detection was ~11 fg-mL 1.4 fM while the biosensor probe efficiently distinguished between single-base mismatch and noncomplementary sequence target.

KeywordsGold nanoparticle Zeta potential Biosensor Colloidal stability Quantum dot DNA detection Electronic supplementary materialThe online version of this article doi:10.1186-s11671-016-1748-3 contains supplementary material, which is available to authorized users.

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Author: Oluwasesan Adegoke - Enoch Y. Park

Source: https://link.springer.com/







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