Mechanism of mercury detection based on interaction of single-strand DNA and hybridized DNA with gold nanoparticles

• Published in: Talanta (Oxford) 2010-10, Vol.82 (5), p.1642-1646
• Main Authors: Zuo, Xinbing, Wu, Huanan, Toh, Juhong, Li, Sam Fong Yau
• Format: Article
• Language: English
• Subjects: Absorption; Analytical chemistry; Base Pair Mismatch; Base Sequence; Chemistry; Colorimetry; DNA; DNA Probes - chemistry; DNA, Single-Stranded - chemistry; Exact sciences and technology; Fluorescence Resonance Energy Transfer; Gold - chemistry; Gold nanoparticles; Hg 2; Mercury Compounds - analysis; Mercury detection; Metal Nanoparticles - chemistry; Molecular Sequence Data; Reproducibility of Results; Sensitivity and Specificity; Thymine - chemistry
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2010.07.031

Mechanisms of interaction of single-strand DNA and hybridized DNA on gold nanoparticles in the presence of Hg 2+ was studied in this work. Recently the detection of Hg 2+ using unmodified gold nanoparticles (AuNPs) combined with DNA is becoming a promising technique with the advantages of simplicity, cost-effectiveness and high sensitivity. However, few studies focused on the interaction of ssDNA and hybridized DNA on AuNPs to date. In the present work, we compared the interactions of different DNA probes on AuNPs using both absorption and fluorescence detection. It was found that there were only small partial dsDNA dissociated from the surface of AuNPs after hybridization in the presence of Hg 2+. Moreover, we found that the aggregated AuNPs/DNA system tended to be dispersed again with increasing Hg 2+ concentration up to 250 μM. Based on these results, the mechanisms of mercury detection based on interaction between DNA-conjugated gold nanoparticles were investigated. Positively charged dsDNA could bind to the surface of AuNPs and dominate the electrostatic interactions and consequently aggregation of the AuNPs/DNA system.