Analytical Sciences最新文献

DNA aptamers have attracted attention as an alternative modality for biomolecules due to their excellent target binding specificity and thermal stability, and they are also expected to be applied as artificial agonists for receptor proteins. DNA aptamer agonist TD0 targeting the receptor of fibroblast growth factor (FGFR), which plays an important role in the fields of wound healing and regenerative medicine, has been reported to induce cellular responses as well as its native ligands. However, it was also noted that there were some different responses upon long-term stimulation, suggesting that the intracellular signals induced by DNA aptamer agonist TD0 are different from those of natural ligands. In this paper, we comprehensively analyzed the intracellular signals induced by DNA aptamer agonist TD0 targeting FGFR1, and compared them with those by natural protein ligand FGF2. It was found that the intracellular signals were highly similar for short-term stimulation. On the other hand, the receptor and the downstream cellular signals showed different activation behaviors for long-time stimulation. Evaluating the stability and sustained activity of DNA aptamer agonist TD0 and FGF2 in the medium suggested that ligand stability may be important in properly regulating cellular responses.

Arsenic (As(V)) contamination in aqueous resources poses a significant environmental, and public health risk due to its high toxicity. To address this challenge, we synthesized and characterized novel reduced graphene oxide/magnetite (rGO/Fe₃O₄) nanocomposites, which are efficient adsorbents for removing As(V). Using a co-precipitation method, we obtained three distinct sizes of rGO/Fe₃O₄ nanocomposites by controlling the salt concentration (Fe²⁺: Fe³⁺) ratios. Analysis of the adsorption ability of the samples shows that the adsorption efficiency can reach up to 98.10% within 90 min, and the adsorption capacity value reaches 20.55 mg/g. Furthermore, these test data are ably consistent with both the pseudo-second-order model and the Langmuir model, based on which the adsorption mechanism has been proposed. These results show that the rGO/Fe₃O₄ nanocomposites that we synthesized are a potential adsorbent for the removal of heavy metals from water.

We have developed sulphur-doped graphitic carbon nitride (S-GCN) anchored Ag@AgCl electrocatalyst through a green technique for the first time for the electrochemical sensing of chloramphenicol. The Ag@AgCl nanoparticles were synthesized using Rhoeo discolor (Tradescantia spathacea) plant extract without the use of any external halide source. As per our knowledge, this is the first time Rhoeo discolor (Tradescantia spathacea) plant extract was used for the synthesis of Ag@AgCl nanoparticles without the use of any external halide source. Using sonochemical technique, the green synthesized nanoparticle was combined with S-GCN to form Ag@AgCl/S-GCN electrocatalyst. The synthesized materials were characterized by suitable techniques such as UV-visible spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and elemental analysis. The electrocatalytic reduction mechanism of chloramphenicol was studied with the help of electrochemical impedance spectroscopy, cyclic voltammetry, and linear sweep voltammetry. The Ag@AgCl/S-GCN modified electrode has shown a linear response in the range of 1 to 650 μM, with a LOD of 420  $\text{nM}$ . Further, the practical application of the developed sensor was analyzed using real samples such as milk and honey and satisfactory recovery rates were observed.

Herein, by combining the benzofuranone-derived fluorophore and the carbamate recognition group, a fluorescent probe named BFO-CarE was developed for monitoring the carboxylesterase (CarE) level in pulmonary cells under the permissive hypercapnia condition. It showed a notable fluorescence response towards CarE at 570 nm under the excitation of 510 nm. The in-solution tests revealed the advantages of BFO-CarE including high sensitivity, high specificity, relatively rapid response, and high steadiness. It was also low-toxic upon the pulmonary cell lines. During the intracellular imaging in pulmonary cells, BFO-CarE achieved the monitoring of the CarE level in both inhibition and activation status. In particular, BFO-CarE realized the visualization of the affection of the permissive hypercapnia condition on the CarE level, which indicated the hypoxia tolerance of CarE. This work was informative for investigating the impact of hypoxia in pulmonary cells, and the corresponding anaesthesia-related approaches.

A new method for speciation analysis of tellurium(IV) and Te(VI) using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) has been developed. Tellurium(IV) and Te(VI) were completely separated using a reversed-phase column with an L-cysteine eluent under an isocratic elution condition. The detection limits (3σ) of Te(IV) and Te(VI) monitored by HPLC-ICP-MS at m/z 125 were 1.4 and 0.5 ng g^-1, respectively. The proposed determination method was precisely applied to assessing total concentrations and chemical species of Te in several standard solutions. The recovery rates of Te(IV) and Te(VI) were almost 100% from the results of the addition-recovery examinations, even when a high matrix sample such as seawater was measured. The method was applied to seawater samples and electronic products, and was proved quite effective for environmental risk assessment.

Macrophages are a type of white blood cells that play key roles in innate immune responses as a part of cellular immunity for host defence and tissue homeostasis. To perform diverse functions, macrophages show high plasticity by transforming to polarized states. They are mainly identified as unpolarized, pro-inflammatory and antiinflammatory states and termed as M0, M1 and M2 macrophages respectively. Discriminating polarized states is important due to strict implication with inflammatory conditions resulting in many diseases as chronic inflammation, neurodegeneration, and cancer etc. Many polarization protein markers have been identified and applied to investigate expression profiles through PCR and other techniques with antibodies. However, they are time and cost consuming and sometimes show insufficient performances. We focused on the mannose receptor (CD206) as representative marker of M2 macrophage recognising terminal mannose. We developed dose dependent mannosylated fluorescent proteins (FPs) by conjugations with mannose derivative for around 20 modifiable sites on FPs surfaces. Maximum modifications did not spoil various features of FPs. We found further sensitive and specific discriminations among M2, M1 and M0 macrophages after treating polarized macrophages with adequately conditioned FPs compared to already established approaches using anti CD206 antibody through flow cytometric analysis. These results might be derived from direct ligand utilizations and increased avidity due to multivalent bindings with abundantly modified multimeric FPs. Our strategy is simple but addresses disadvantages of preceding methods. Moreover, this strategy is applicable to detect other cell surface receptors as FPs can be modified with ligands or recognizable aptamer like molecules.

A reflective surface plasmon resonance (SPR) sensor was evaluated for real-time monitoring of scale deposition. The sensor consists of an optical fiber, only 5 mm at the gold-coated tip of the sensing area. The effect of silica growth on the sensor response was evaluated using a Na₂SiO₃ solution. The sensitivity of the sensor to silica was 1.6 ± 0.3 nm per one immersion in the solution of 1000 mg/L (as SiO₂) at 85 °C and subsequnt air drying, as indicated by the SPR peak shift. The amount of silica deposited on the gold surface was measured by the quartz crystal microbalance method, and the SPR sensitivity of 0.089 nm/ng to silica mass was obtained. The detection limit (3σ) of the SPR sensor was 17 ng, corresponding to a thickness of 2.5 nm for amorphous silica. The SPR sensor was tested in geothermal brine sampled at the Sumikawa Geothermal Power Plant, where a clear SPR shift was observed, suggesting the effectiveness of the SPR sensor for scale monitoring.