Highly Sensitive and Selective Spectroscopic Detection of Mercury(II) in Water by Using Pyridylporphyrin–DNA Conjugates

Abstract

Single-labeled pyridylporphyrin-DNA conjugates are reported as highly sensitive and selective spectroscopic sensors for mercury(II) ions in water. The effects of chemical structure (thymine versus adenine), number of nucleotides (monomer versus octamer), and porphyrin metalation (Zn versus free base) on the sensitivity and selectivity of mercury(II) detection are explored. The results indicated that pyridylporphyrin rather than the nucleobase plays a crucial role in mercury(II) sensing, because porphyrin conjugates with both adenosine and thymidine exhibited excellent mercury(II) detection. Mercury(II) recognition was shown in emission quenching, as well as in a redshift of the porphyrin Soret band absorption. The limit of detection (LOD, 3σ/slope) of zinc(II) pyridylporphyrin-5'-oligodeoxythymidine (ZnPorT8) obtained by fluorescence quenching was calculated to be 21.14 nM. Other metal cations (Zn(2+), Cd(2+), Pb(2+), Mn(2+), Ca(2+), Ni(2+), Mg(2+), Fe(2+), Cu(2+), and Na(+)) did not interfere with the emission and absorption sensing of mercury(II). Free-base porphyrin-oligothymine conjugate 2HPorT8 displayed similar sensitivity to ZnPorT8 but different selectivity. The results also implied that the sensing properties of porphyrin-deoxythymidine conjugates could potentially be tuned by porphyrin metalation.

Porphyrinoid biohybrid materials as an emerging toolbox for biomedical light management

“…In particular, Balaz and co-workers studied their dependency on the presence of thymine or adenine, the number of nucleobases, and the Por central metal. 198 Linking adenine instead of thymine produced a decrease in the limit of detection of Hg 2+ in water, while the combination of zinc as the central metal and oligodeoxythymidine as the sensing unit showed the best results toward this mercury cation. Cytosine-substituted Co(II)Por and Zn(II)Por have been used, on the other hand, as nucleotide receptors.…”

A chemical sensor based on a photonic-crystal L3 nanocavity defined in a silicon-nitride membrane

“…Indeed, we note that porphyrin based materials have been used to selectively recognize a variety of different materials, including dopamine [39] and mercury(II) [40]. Sensors utilizing other polymers that undergo swelling can be envisaged to detect vapors such as chloroform [41] or ammonia [42].…”

A highly sensitive and reversible chemosensor for Hg2+ detection based on porphyrin‐thymine conjugates

“…However, chemosensor studies based on porphyrin‐thymine conjugates have seldom been reported so far, although porphyrin is among the best known self‐associating dyes in poor solvents, and this self‐aggregation is clearly reflected by changes in the absorption spectra (Liu et al ., ; Arai and Segawa, ). In this regard, porphyrins and their derivatives represent very attractive components of molecular sensors due to the fact that porphyrins are highly flexible and a number of structural changes involving different central metal ions and peripheral substituents can be introduced, which in turn is reflected by changes in the emission and absorption spectra (Fang and Liu, , Yang et al ., , Choi et al ., , Bettini et al ., ). In general, porphyrins exhibit an intense and narrow absorption band in the visible spectrum between 400 and 460 nm as well as an emission band in the red part of the spectrum (550–750 nm) (Karolczak et al ., ).…”