Sensitivity For Hg2 Research Articles

Multifunctional Magnetic Mesoporous Silica Nanocomposites with Improved Sensing Performance and Effective Removal Ability toward Hg(II)

In the present work, a multifunctional inorganic-organic hybrid nanomaterial (MMS-Py) was prepared by the immobilization of a pyrene-based receptor (Py) within the channels of magnetic mesoporous silica nanocomposites (MMS), and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N(2) adsorption/desorption, superconducting quantum interference device, and photoluminescence spectra. This multifunctional nanomaterial exhibits superparamagnetic behavior, ordered mesoporous characteristics, and significantly improved fluorescence sensing properties that allow for highly sensitive and reproducible Hg(2+) detection. The fluorogenical responses of MMS-Py are stable over a broad pH range. A detection limit of 1.72 ppb is obtained, which is 2 orders of magnitude lower than that based on bulk mesoporous materials. Additionally, this nanomaterial shows high performance in convenient magnetic separability and efficient removal of Hg(2+). These results indicate that these multifunctional nanocomposites may find potential applications for simple detection and easy removal of Hg(2+) in biological, toxicological, and environmental areas.

Highly Sensitive Fluorometric Hg2+ Biosensor with a Mercury(II)‐Speci?c Oligonucleotide (MSO) Probe and Water‐Soluble Graphene Oxide (WSGO)

AbstractA highly sensitive and selective, "turn‐on" and simple Hg2+ biosensor is reported by using water‐soluble graphene oxide (WSGO) and dye‐labeled mercury(II)‐specific oligonucleotide (MSO) probe. The probe is rich of thymine (T) and can readily form the stem‐loop structure which consists of the T‐Hg2+‐T configuration. In the absence of Hg2+, the probe exists as a random coil conformation which can be readily adsorbed on the surface of WSGO by strong noncovalent binding of bases, as a result, the fluorescence of the dye labeled on the terminus of the MSO is strongly quenched by the efficient electron/energy transfer from the dye to WSGO. Upon addition of Hg2+, the formation of the T‐Hg2+‐T structure releases the MSO from the surface of WSGO, resulting in a restoration of the fluorescence of dye‐labeled MSO probe. Based on this observation, a highly sensitive and selective Hg2+ sensor is developed, which can work with "turn‐on" mode in aqueous solutions at room temperature. By using the fluorometric method, the limit of detection for Hg2+ can reach picomolar range (187 pmol·L−1), and it is demonstrated that the biosensor is highly selective and only minimally perturbed by a wide range of non‐specific metal ions.

A fluorescence turn-on Hg<sup>2+</sup> probe based on rhodamine with excellent sensitivity and selectivity in living cells

A highly sensitive and selective Hg2+ probe 4 based on rhodamine-b was developed and characterized. In consideration of environmental and biological application, we connected a water soluble receptor group (sulfonated β-naphtol) and rhodamine-b together through hydrazine hydrate in high yield. The result turns out that this compound not only exhibits excellent sensitivity and selectivity toward Hg2+, but also shows well cell permeability and compatibility in vitro.

Polythymine Oligonucleotide‐Modified Gold Electrode for Voltammetric Determination of Mercury(II) in Aqueous Solution

AbstractPolythymine oligonucleotide (PTO)‐modified gold electrode (PTO/Au) was developed for selective and sensitive Hg2+ detection in aqueous solutions. This modified electrode was prepared by self‐assembly of thiolated polythymine oligonucleotide (5′‐SH‐T15‐3′) on the gold electrode via AuS bonds, and then the surface was passivated with 1‐mercaptohexanol solution. The proposed electrode utilizes the specific binding interactions between Hg2+ and thymine to selectively capture Hg2+, thereby reducing the interference from coexistent ions. After exchanging the medium, electrochemical reduction at −0.2 V for 60 s, voltammetric determination was performed by differential pulse voltammetry using 10 mM HEPES; pH 7.2, 1 M NaClO4 as supporting electrolyte. This electrode showed increasing voltammetric response in the range of 0.21 nM Hg2+, with a relative standard deviation of 5.32% and a practical detection limit of 60 pM. Compared with the conventional stripping approach, the modified electrode exhibits good sensitivity and selectivity, and is expected to be a new type of green electrode.

Rhodamine-based chemosensor for Hg2+ in aqueous solution with a broad pH range and its application in live cell imaging

A new fluorescent probe, rhodamine B derivative (1) bearing an 8-hydroxyquinoline group, was synthesized and displayed highly selective and sensitive Hg(2+)-amplified absorbance and fluorescence emission above 500 nm in aqueous solution with a broad pH range 4-9. It was found that mercury ions coordinate reversibly to 1 and the spirolactam ring of 1 was opened, forming a 1 : 1 metal-ligand complex. Furthermore, this sensor was applied for in vivo imaging in HeLa cells to confirm that 1 can be used as a fluorescent probe for monitoring Hg(2+) in living cells.

Highly selective and sensitive Hg2+ fluorescent sensors based on a phosphane sulfide derivative

A series of fluorescent sensor molecules based on a phosphane sulfide derivative were designed and synthesized. The effect of the distance between the complex entities as well as the number and the length of fluorophores was investigated using both steady-state and time-resolved fluorescence methods. The complexation behavior of these sensor molecules, which have a distinct affinity for Hg(2+), is reported. The coordination of Hg(2+) induces a photoinduced electron transfer from fluorophore to the complexed mercury and results in a significant decrease of the fluorescence. Theses sensors exhibit very low detection limits in CH(3)CN/H(2)O (80/20 v:v) and excellent sensitivity to Hg(2+) over other potentially interfering cations such as Na(+), K(+), Mg(2+), Ca(2+), Cu(2+), Ag(+), Zn(2+), Cd(2+) and Pb(2+).

Fluorescent imaging of acute mercuric chloride exposure on cultured human kidney tubular epithelial cells

Imaging of intracellular mercuric ion is necessary for mechanism of renal toxicity of exposure to HgCl2. The distribution of Hg2+ inside a living cell, however, is still invisible due to the lack of high selective and sensitive fluorescent molecular probe for Hg2+. A new fluorescent probe, EPNP, was applied to the cultured cells of human kidney proximal tubular epithelial cell line (HKC) in the presence of HgCl2 and some other bivalent ions. The relative fluorescence intensity of EPNP was measured and fluorescence images were taken by laser scanning confocal microscope. Results showed it led to an Hg2+ concentration- and time-dependent increase in fluorescence intensity, and responded weakly for some other heavy and transition metal ions. It could be seen during acute exposure on HKC cells, Hg2+ locate perinuclear, and on nuclear membrane, which was beyond what one knew before. EPNP is a real-time and on-line probe for imaging Hg2+ in a living cell due to its high selectivity and sensitivity for Hg2+ and slow bleaching/fading. Both the probe and the new results about the distribution of intracellular Hg2+ may be helpful for relevant biologic research.

Messenger RNA induction in cellular salt tolerance of Alfalfa (Medicago sativa)

A salt tolerant alfalfaMedicago sativa L. cell line (HG2-N1) has been selected for growth in 171 mM NaCl. The salt tolerance characteristic is stable and is retained after growth in absence of salt selection for two months.In vitro translation was used to compare mRNA composition from the salt tolerant HG2-N1 and parent salt sensitive HG2 cell lines grown in the presence and absence of 171 mM NaCl. The results suggest that the mRNA composition differs between HG2-N1 and HG2 in a number of RNA species. The salt tolerant HG2-N1 shows both increases and decreases in specific polypeptides as compared to HG2. Many of the enhanced polypeptide bands from mRNA in the salt tolerant HG2-N1 variant appear to be constitutively expressed, since they can be detected from HG2-N1 cells grown in presence and absence of NaCl, but the expression of a few bands may depend on the presence of added NaCl. Most enhanced polypeptides, which are detected from mRNA in the salt tolerant variant HG2-N1 (grown on NaCl) are different from polypeptide bands enhanced in the salt sensitive HG2 line as a result of 24 hour salt stress. Similar results were obtained from two dimensional analysis ofin vivo labeled polypeptides. At least one isolated cDNA clone shows selective expression of mRNA in salt tolerant cells grown in NaCl. These results indicate that adaptive mechanisms for salt tolerance may differ in some aspects from acute stress mechanisms.