Abstract
Nucleic acids that exhibit a high affinity toward noble and transition metal ions have attracted growing attention in the fields of metal ion sensing, toxic metal ion removal, and the construction of functional metal nanostructures. In this study, fluorescent nanoparticles (biodots) were synthesized from DNA, RNA, and RNA nucleotides (AMP, GMP, UMP, and CMP) using a hydrothermal (HT) method, in order to study their metal ion sensing characteristics. The fluorescent properties of biodots differ markedly between those prepared from purine and pyrimidine nucleobases. All biodots demonstrate a high sensitivity to the presence of mercury cations (Hg2+), while biodots prepared from DNA, RNA, and guanosine monophosphate (GMP) are also sensitive to Ag+ and Cu2+ ions, but to a lesser extent. The obtained results show that biodots inherit the metal ion recognition properties of nucleobases, while the nucleobase composition of biodot precursors affects metal ion sensitivity and selectivity. A linear response of biodot fluorescence to Hg2+ concentration in solution was observed for AMP and GMP biodots in the range 0–250 μM, which can be used for the analytic detection of mercury ion concentration. A facile paper strip test was also developed that allows visual detection of mercury ions in solutions.
Highlights
Accepted: 9 September 2021Nucleic acids form complexes with a broad variety of metal cations [1]
We showed that the biodots prepared in this study can be used for analytical detection of Hg2+ concentration in aqueous solutions, as well as for a facile visual detection of Hg2+, Ag+, Cu2+, and a number of other heavy metal ions, using biodot-impregnated paper strips
Fluorescent nanoparticles synthesized from nucleic acids inherit the high affinity of nucleic acids to Hg2+ and, to a lesser extent, to Ag+ and Cu2+, which was utilized for the sensing of these heavy metal ions in aqueous solutions, as well as for naked eye detection of these ions
Summary
Accepted: 9 September 2021Nucleic acids form complexes with a broad variety of metal cations [1]. The strong DNA affinity for heavy metal ions [1] was used for the sensing [6,7] and removal [8,9,10] of Hg2+ , Pb2+ , and other toxic metal ions from water. Nanobiosensing is a rapidly developing scientific field [11], and a vast number of materials for metal ion sensing have been prepared using the hydrothermal (HT) treatment of biomass [12], which involves the heating of aqueous solutions or dispersions of biomass, usually at 200–300 ◦ C in an autoclave. CDs produced from biomass have high fluorescence [14], low toxicity [15], and low price compared to conventional fluorescent dyes. Applications of CDs in energy [16], catalysis [17], biomedicine [18], and other fields are anticipated
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