3 research outputs found
Visual Assay of Glutathione in Vegetables and Fruits Using Quantum Dot Ratiometric Hybrid Probes
Future
food safety monitoring with simple, fast, and visual methods
has become increasingly important. Accordingly, this work was designed
to construct a new-style dual-emission ratiometric fluorescent probe
(CdSe@SiO<sub>2</sub>@CdTe) for visual assay of glutathione (GSH)
with a “turn on” strategy. After adding Hg<sup>2+</sup>, the red fluorescence of the outer CdTe quantum dots (QDs) was quenched
through both electron transfer and ion-binding processes. Upon the
addition of GSH, the red fluorescence occurred again owing to the
strong affinity between GSH and Hg<sup>2+</sup>, whereas the inner
green fluorescence of CdSe QDs was unchanged, leading to a clearly
recognizable fluorescence color change (from green to orange–red).
In the concentration range from 0.1 to 10 ÎĽM, the relative fluorescence
intensity ratios (<i>I</i><sub>619</sub>/<i>I</i><sub>535</sub>) showed an excellent linear correlation with the concentration
of GSH, and the detection limit was as low as 42 nM under optimal
conditions. Meanwhile, the ratiometric hybrid probes were successfully
applied for direct visual sensing GSH in real vegetable and fruit
samples
Plasma Lipidomics Investigation of Hemodialysis Effects by Using Liquid Chromatography–Mass Spectrometry
Chronic
kidney disease (CKD) has been a global health problem that
has a great possibility of being developed into uremia in the end.
Hemodialysis (HD) is the most commonly used strategy for treating
uremic patients; however, the patients still have a high risk of suffering
various complications. It is well recognized that lipid disorder usually
occurs in maintenance HD patients. To systemically study the effects
of HD on lipid metabolism associated with uremia, we employed an ultraperformance
liquid chromatography–quadrupole-time-of-flight mass spectrometry
(UPLC-Q-TOF/MS)-based lipidomics method. A total of 87 human plasma
samples from patients with prehemodialysis (pre-HD)/posthemodialysis
(post-HD) treatment and the healthy controls were enrolled in the
study. As compared with pre-HD patients, many plasma lipids showed
significant changes (<i>p</i> < 0.05) in patients receiving
HD therapy. Specifically, sum of free fatty acids (FFA) as well as
saturated FFA and eicosanoids and sums of lyso-phosphatidylinositols
and lyso-phosphatidylethanolamines, FFA 16:1/FFA 16:0, and FFA 18:1/FFA
18:0 were obviously higher in the pre-HD group than in the controls
while they were significantly lower in patients after HD. These results indicated that UPLC-Q-TOF/MS-based lipidomics is a
promising approach to investigate lipid alterations in relation to
uremia and it is helpful to understand complex complications involved
in HD patients
Dual-Metal Centered Zirconium–Organic Framework: A Metal-Affinity Probe for Highly Specific Interaction with Phosphopeptides
The
highly specific affinity between probes and phosphopeptides is the
fundamental interaction for selective identification of phosphoproteomes
that uncover the mechanisms of signal transduction, cell cycle, enzymatic
regulation, and gene expression in biological systems. In this study,
a metal-affinity probe possessing both interactions of metal oxide
affinity chromatography (MOAC) and immobilized metal ion affinity
chromatography (IMAC) was facilely prepared by immobilizing zirconiumÂ(IV)
on a zirconium–organic framework of UiO-66-NH<sub>2</sub>,
which holds dual-metal centers of not only the inherent Zr-O cluster
but also the immobilized ZrÂ(IV) center. This dual-metal centered zirconium–organic
framework (DZMOF) demonstrates as a highly specific metal-affinity
probe toward the extraction of phosphopeptides due to the metal-affinity
interactions of MOAC and IMAC toward either mono-phosphorylated or
multi-phosphorylated peptides. The binding energies of zirconium 3d<sub>5/2</sub> and 3d<sub>3/2</sub> in this DZMOF are 183.07 and 185.47
eV, respectively, which are higher than those of the intact UiO-66-NH<sub>2</sub> (182.84 and 185.17 eV, respectively), confirming the higher
metal-affinity interaction between the DZMOF and phosphopeptides.
This high metal-affinity probe presents an unprecedented strong performance
in anti-nonspecific interference during the capturing of phosphopeptides
of β-casein with the molar ratio of β-casein vs bovine
serum albumin up to ca. 1:5000. The enrichment of phosphopeptides
from a human saliva sample by DZMOF further confirms the great potential
of DZMOF in the extraction of low-abundance phosphopeptides for real
complex biological samples