Correction: Exploiting the high conjugation capacity of creatinine on 3,3′-dithiodipropionic acid di(N-hydroxysuccinimide ester) functionalized gold nanoparticles towards sensitive determination of mercury (II) ion in water

Exploiting the high conjugation capacity of creatinine on 3,3′-dithiodipropionic acid di(N-hydroxysuccinimide ester) functionalized gold nanoparticles towards sensitive determination of mercury (II) ion in water

Chromatic analysis by monitoring unmodified silver nanoparticles reduction on double layer microfluidic paper-based analytical devices for selective and sensitive determination of mercury(II)

Sensitive determination of bioaccessible mercury in complex matrix samples by combined photochemical vapor generation and solid phase microextraction coupled with microwave induced plasma optical emission spectrometry

A novel electrode modified with oligonucleotide and microporous gold was fabricated for the determination of mercury by differential pulse adsorptive stripping voltammetry (DPAdSV). Microporous gold was synthesized by electrochemical reduction using dynamic hydrogen bubble template. The oligonucleotide was immobilized on microporous gold by self-assembly. The prepared electrode exhibited an improved electrochemical response for mercury(II) ion because of the large surface area and excellent electron transfer capacity provided by microporous gold and the specific coordination between mercury ion and thymine bases in oligonucleotides. Under the optimal experiment conditions, the oligonucleotide functionalized microporous gold electrode had a linear relationship between the stripping current and mercury ion concentration in the range from 0.5 to 30 µg/L with a detection limit of 0.021 µg/L. Moreover, the prepared electrode exhibited good selectivity, reproducibility, repeatability and stability. Furthermore, the prepared electrode was applied to detect mercury in tap water with satisfactory results.

A selective and sensitive determination method for mercury (Hg) ions in river and sea water by reversed‐phase high performance liquid chromatography (HPLC) has been developed. A one milliliter water sample containing Hg(II) ions was put into a 4 mL sample tube. To the sample tube, 2 mL of 0.5 mol/L (M) tetrabutylammonium bromide (TBA‐Br) solution was added to form a neutral Hg compound. The Hg compound subsequently became pre‐concentrated in a mini‐column packed with 5 µm ODS. By switching the valve, the Hg compound was separated in an ODS analytical column, and detected with a photometric detector (255 nm). These processes occur automatically, except for the addition of water samples and 0.5 M TBA‐Br. The correlation coefficient of the calibration curves (metal concentration vs. peak area) obtained with 1 mL of mercury standard was more than 0.9995 over the range of 1 ng/mL (ppb) to 10 µg/mL (ppm). The detection limit of Hg ions in 1 mL solution was 0.5 ppb, which corresponded to 3 times the standard deviation (N=8) of the blank peak area. Effects of foreign ions on the method were investigated with 0.1‐ppm Hg standard and 55 metal ions. Forty two metal ions of 200 ppm did not interfere with the determination of Hg(II) ions. Tolerance limits of Pd(II) and Ag(I) were 5 and 10 ppm, respectively. Recovery tests were carried out by the presented HPLC method with spiked river and sea water samples. The recoveries with a spiked river water sample for 400‐, 40‐, and 4‐ppb Hg ion (N=5) were 100.1±0.2%, 100.1±1.3%, and 97.9±2.3%, respectively. Those with a sea water sample for 400‐, 40‐, and 4‐ppb Hg ion (N=5) were 100.9±1.0%, 99.9±1.8%, and 99.1±9.4%, respectively.

A selective and sensitive determination method for mercury (Hg) ions in river water by reversed phase high performance liquid chromatography (HPLC) has been developed. Two mL of water sample containing Hg(II) ions was put into a 4 mL sample tube. To the sample tube, 500 µL of 2 mol/L (M) acetate buffer solution (pH 4.5), and 50 µL of 0.01 M 2-mercaptopyrimidine (MP) were added to form a neutral Hg chelate. The Hg chelate subsequently became preconcentrated in a reversed phase mini column. By switching the valve, the Hg chelate was separated and detected at 255 nm. These processes occur automatically, except for the addition of water samples, buffer, and MP solutions. The correlation coefficients of the calibration curves obtained with 2 mL of mercury standard were more than 0.999 over the range of 20 ng/mL (ppb) to 10 µg/mL (ppm). The detection limit of Hg ions in 2 mL solution was 1.6 ppb, which corresponded to 3 times the standard deviation (N = 10) of the blank peak area. Effects of foreign ions on the determination of 0.2 ppm Hg were investigated with 57 metal ions. Almost none of the ions interfered except for Au(III), Pd(II), Ag(I), and Co(II) ions. The recoveries with spiked river water samples for 5, 0.5, and 0.05 Hg ion (N = 7) were 99.7 ± 0.4%, 100.3 ± 0.3%, and 100.7 ± 0.7%, respectively.

This work reportsnon-cross-linking of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) stabilized copper oxide nanoparticles for the detection of mercury ions through the resonance Rayleigh scattering method.

Mercury is a very toxic element that is widely spread in the atmosphere, lithosphere, and surface water. Concentrated mercury poses serious problems to human health, as bioaccumulation of mercury within the brain and kidneys ultimately leads to neurological diseases. To control mercury pollution and reduce mercury damage to human health, sensitive determination of mercury is important. This article summarizes some current sensors for the determination of both abiotic and biotic mercury. A wide array of sensors for monitoring mercury is described, including biosensors and chemical sensors, while piezoelectric and microcantilever sensors are also described. Additionally, newly developed nanomaterials offer great potential for fabricating novel mercury sensors. Some of the functional fluorescent nanosensors for the determination of mercury are covered. Afterwards, the in vivo determination of mercury and the characterization of different forms of mercury are discussed. Finally, the future direction for mercury detection is outlined, suggesting that nanomaterials may provide revolutionary tools in biomedical and environmental monitoring of mercury.

An ion-imprinted polymer-coated maghemite nanoparticle adsorbent for selective extraction of Hg(II) ion was synthesized. The polymerization was carried out by the new mercaptoethylamino monomer as the functional monomer, ethylene glycol dimethacrylate as the crosslinking agent and ammonium persulfate as the initiator in the presence of Hg(II) ions as the template. The synthesized nanoparticles were characterized using FT-IR, XRD and TEM analysis. The effects of various factors that may affect the solid-phase extraction of Hg(II) (i.e. pH, adsorbent dosage, contact time) and the preconcentration factor (i.e. initial sample volume, type and volume of the desorbing solvent) were optimized using one-at-a-time method. The maximum adsorption capacity was obtained as 72.8 mg g−1. Compared with the non-imprinted polymer-coated nanoparticles, the synthesized ion-imprinted polymer-coated nanoparticles had higher selectivity for Hg(II). The detection limit was found to be 4.1 μg L−1 for an initial sample volume of 200.0 mL using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace amounts of mercury in tap water and wastewater samples.

Retinal dopamine is believed to be involved in the development of myopia, which is projected to affect almost half of the world population's visual health by 2050. Direct visualization of dopamine in the retina with high spatial precision is essential for understanding the biochemical mechanism during the development of myopia. However, there are very few approaches for the direct detection of dopamine in the visual system, particularly in the retina. Here, we report surface-enhanced Raman scattering (SERS)-based dopamine imaging in cells and retinal tissues with high spatial precision. The surface of gold nanoparticles is modified with N-butylboronic acid-2-mercaptoethylamine and 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester), which shows excellent specific reaction with dopamine. The existence of dopamine triggers the aggregation of gold nanoparticles that subsequently form plasmonic hot spots to dramatically increase the Raman signal of dopamine. The as-synthesized SERS nanoprobes have been evaluated and applied for dopamine imaging in living cells and retinal tissues in form-deprivation (FD) myopia guinea pigs, followed by further investigation on localized dopamine levels in the FD-treated mice. The results suggest a declined dopamine level in mice retina after 2-week FD treatment, which is associated with the development of myopia. Our approach will greatly contribute to better understanding the localized dopamine level associated with myopia and its possible treatments. Furthermore, the imaging platform can be utilized to sensing other important small molecules within the biological samples.

Ferrocene (Fc)-functionalized gold nanoparticles (Fc-GNPs) have been synthesized and tested for anti-tumor activity in breast cancer and normal cell lines MCF-7 and MCF-10a, respectively. Synthesized Fc-GNPs exhibited homogeneous particle distribution as evident from transmission electron microscopy (TEM). Energy dispersive X-ray spectroscopy (EDX) showed the homogenous ligation of Fc on gold nanoparticles. Atomic emission spectroscopy-inductively coupled plasma (AES-ICP) was used to quantify the amount of Fc per GNPs and found to be 84 Fc units per GNPs. Gel electrophoresis and UV–visible (UV–Vis) analysis indicated that Fc-GNPs interacted with DNA. Binding interactions of Fc-GNPs with DNA were investigated using UV–Vis spectrum. Hypochromism and shift towards shorter wavelength was observed with addition of DNA in Fc-GNPs, indicating electrostatic mode of binding of DNA with Fc-capped AuNPs. Drug release experiments performed using dialysis bag method revealed that maximum amount of Fc was released from GNPs in 10–19 h. Cancer cell line treatments showed that Fc-GNPs were comparatively more toxic to MCF-7 (breast cancer cell line) as compared to MCF-10a (breast normal cell line) at 20 μM Fc-GNPs. We did not find any significant differences in Fc and Fc-GNPs treatment in breast normal cell line MCF-10a at 10 μM or 20 μM. However, the toxic effect of the Fc increased sparingly when concentration was raised to 20 μM from 10 μM. Interestingly, Fc-GNPs have higher anti-tumor effect as compared to Fc alone in cancer cell line.

Sensitive determination of mercury in tap water by cloud point extraction pre-concentration and flow injection-cold vapor-inductively coupled plasma optical emission spectrometry

Ultrasensitive determination of mercury by ICP-OES coupled with a vapor generation approach based on solution cathode glow discharge

Sensitive determination of mercury by a miniaturized spectrophotometer after in situ single-drop microextraction

Today, understanding the interaction between DNA molecule with nanoparticles and functionalized nanoparticles has a significant importance in medical applications and targeted drug delivery. Molecular dynamics simulation on double-stranded molecule with the structure of the double helix and sequence of (CCTCAGGCCTCC) was performed in three states. The aim was to evaluate the effect of gold nanoparticles (GNPs) with partial negative charge on the stability of a DNA molecule. During the simulation process, the GNPs become closed to the DNA molecule and phosphate groups of the DNA molecule guided the nanoparticles toward its major groove. At the end of the DNA molecule chain, the terminal nucleotide of the chain was laid flat on the surface of the GNPs due to excessive exposure to solvent molecules and occurrence of peeling and untwisting states. According to the results, proximity of the GNPs and functionalized GNPs to the DNA molecule led to increased configuration entropy. While conformational energy and van der Waals energy of the DNA molecule increased in the presence of the GNPs and functionalized GNPs, there was a reduction and an increase in the number of hydrogen bonds between complementary bases in the presence of the GNPs and functionalized GNPs, respectively. Radial distribution function was estimated for water molecules and sodium cations, compared to oxygen atoms of the phosphate group of the DNA molecule. Results were indicative of the release of water molecules from around the DNA molecule in the presence of the GNPs. In addition, the distance between sodium cations and the GNPs decreased. Nevertheless, no such phenomenon occurred in the presence of the functionalized GNPs. Therefore, according to results, it seems that GNPs decreased the stability of the DNA molecule and the functionalized GNPs with partial negative charge caused structural changes and created compression, but did not destroy the double-strand structure of the DNA molecule.