Gold nanorods enhanced resonance Rayleigh scattering for detection of Hg2+ by in-situ mixing with single-stranded DNA

• Published in: Sensors and actuators. B, Chemical Vol. 255; pp. 836 - 842
• Main Authors: Ngernpimai, Sawinee, Matulakun, Piyaporn, Teerasong, Saowapak, Puangmali, Theerapong, Kopwitthaya, Atcha, Kanokmedhakul, Somdej, Sangiamdee, Duangkamon, Chompoosor, Apiwat
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2018
• Subjects: Aggregation; Gold nanorods; Hg2; Resonance Rayleigh scattering; ssDNA; Tap water; Aggregation; Hg2; Gold nanorods; Resonance Rayleigh scattering; Tap water; ssDNA
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.08.129

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•A sensitive resonance Rayleigh scattering method for determination of Hg2+ was developed.•The reaction was simply performed by in-situ mixing of gold nanorods, ssDNA and Hg2+ in one pot.•The reaction took place rapidly and the analysis could be completed within 5min.•The method offers a low detection limit of 0.23nM.
A resonance Rayleigh scattering (RRS) method for determination of Hg2+ concentration using positively charged gold nanorods (GNRs) and thymine-rich single-stranded DNA (ssDNA) was developed. Hg2+ can induce a conformation change of ssDNA from a random coil to a hairpin structure via thymine–Hg2+–thymine coordination. Hairpin shaped DNA possesses a high density of negative charges, therefore it caused in a drastic aggregation of GNRs. This resulted in an enhancement of RRS intensity. In this work, a change in RRS intensity proportional to the concentration of Hg2+ was monitored by spectrofluorometer at excitation and RRS wavelengths of 550nm (λex=λRRS). This method offered a detection limit of 0.23nM, which is lower than the maximum mercury contaminant level specified by the US Environmental Protection Agency. Good precision of analysis was obtained (3.1% relative standard deviation). Furthermore, the method was simple, involving in-situ mixing and sensing in a one-pot solution. Detection was accomplished in 5min. This makes the method advantageous in terms of convenience and rapidity of analysis. The developed method was successfully applied for detection of Hg2+ in tap water samples. Recoveries were found in range of 100.6–119.0%.