12 research outputs found
Bioinspired Polydopamine Sheathed Nanofibers for High-Efficient in Vivo Solid-Phase Microextraction of Pharmaceuticals in Fish Muscle
In this study, electrospun nanofibers
were used as solid-phase
microextraction (SPME) fiber coatings after substituting the water-soluble
sheath of the emulsion electrospun polystyrene (PS)@Plurinic F-127
core–sheath nanofibers with biocompatible and water-stable
polydopamine (PDA) and subsequently being appropriately cross-linked
with glutaraldehyde (GA) to enhance the strength of the electrospun
architecture. The novel custom-made PS@PDA-GA coating was wettable
in aqueous solutions and thus exhibited much higher extraction efficiency
than the nonsheathed PS nanofiber coating and the thicker polydimethylsiloxane
(PDMS) coating. The novel coating also possessed excellent stability
(relative standard deviations (RSDs) less than 7.3% for six sampling-desorption
cycles), interfiber reproducibility (RSDs less than 14.3%), and antibiofouling
ability, which were beneficial for in vivo sampling. The PS@PDA-GA
fiber was used to monitor pharmaceuticals in dorsal-epaxial muscle
of living fish, and satisfactory sensitivities with the limits of
detection in the range of 1.1 (mefenamic acid) to 8.9 (fluoxetine)
ng·g<sup>–1</sup> and comparable accuracies to liquid
extraction were achieved. In general, this study explored a convenient
and effective method to sheath nanofibers for high-efficient in vivo
SPME of analytes of interest in semisolid tissues
Novel Magnetic Microprobe with Benzoboroxole-Modified Flexible Multisite Arm for High-Efficiency <i>cis</i>-Diol Biomolecule Detection
With
regard to regulating a variety of biological events, including
molecular recognition, signal transduction, cell adhesion, and immune
response, <i>cis</i>-diol biomolecules, such as saccharides
and glycoproteins, play vital roles. However, saccharides and glycoproteins
in living systems usually exist in very low abundance, along with
abundant interfering components. High-efficiency detection of saccharides
and glycoproteins is a challenging yet highly impactful area of research.
Herein, we reported a novel magnetic microprobe with a benzoboroxole-modified
flexible multisite arm (PEG 2000-grafted PAMAM dendrimers; the microprobe
was denoted as BFMA-MNP) for high-efficiency saccharides detection.
The extraction capacity was significantly improved by ∼2 orders
of magnitude, because of the integration of the enhanced hydrophilicity
and multivalency effects in benzoboroxoles and the enhanced accessibility
of the binding sites within the PEG 2000-grafted PAMAM dendrimers.
As a result, the proposed approach possessed several advantages, compared
with previous boronic acid-based methods, including ultrahigh sensitivity
(limit of detection was <1 ng/mL), wide linear range (ranged from
0.5 μM to 2000 μM), and applicable in physiological pH
condition. Furthermore, we established a general BFMA-MNP/glycoproteins/AuNPs
sandwich assay to realize the visual glycoprotein qualitative screening
for the first time. The unique sandwich assay possessed the dual nature
of the magnetic separation by BFMA-MNPs and specific coloration by
citrate-coated AuNPs. This visual sandwich assay enabled fast differentiation
of the existence of glycoproteins in complicated samples without any
advanced instruments. We believe the proposed BFMA-MNP microprobe
herein will advance the ideas to detect and identify trace saccharides
and glycoproteins in important fields such as glycomics and glycoproteomics
Novel Electrosorption-Enhanced Solid-Phase Microextraction Device for Ultrafast In Vivo Sampling of Ionized Pharmaceuticals in Fish
Decreasing
the tedious sample preparation duration is one of the
most important concerns for the environmental analytical chemistry
especially for in vivo experiments. However, due to the slow mass
diffusion paths for most of the conventional methods, ultrafast in
vivo sampling remains challenging. Herein, for the first time, we
report an ultrafast in vivo solid-phase microextraction (SPME) device
based on electrosorption enhancement and a novel custom-made CNT@PPY@pNE
fiber for in vivo sampling of ionized acidic pharmaceuticals in fish.
This sampling device exhibited an excellent robustness, reproducibility,
matrix effect-resistant capacity, and quantitative ability. Importantly,
the extraction kinetics of the targeted ionized pharmaceuticals were
significantly accelerated using the device, which significantly improved
the sensitivity of the SPME in vivo sampling method (limits of detection
ranged from 0.12 ng·g<sup>–1</sup> to 0.25 ng·g<sup>–1</sup>) and shorten the sampling time (only 1 min). The
proposed approach was successfully applied to monitor the concentrations
of ionized pharmaceuticals in living fish, which demonstrated that
the device and fiber were suitable for ultrafast in vivo sampling
and continuous monitoring. In addition, the bioconcentration factor
(BCF) values of the pharmaceuticals were derived in tilapia (<i>Oreochromis mossambicus</i>) for the first time, based on the
data of ultrafast in vivo sampling. Therefore, we developed and validated
an effective and ultrafast SPME sampling device for in vivo sampling
of ionized analytes in living organisms and this state-of-the-art
method provides an alternative technique for future in vivo studies
Novel Electrosorption-Enhanced Solid-Phase Microextraction Device for Ultrafast In Vivo Sampling of Ionized Pharmaceuticals in Fish
Decreasing
the tedious sample preparation duration is one of the
most important concerns for the environmental analytical chemistry
especially for in vivo experiments. However, due to the slow mass
diffusion paths for most of the conventional methods, ultrafast in
vivo sampling remains challenging. Herein, for the first time, we
report an ultrafast in vivo solid-phase microextraction (SPME) device
based on electrosorption enhancement and a novel custom-made CNT@PPY@pNE
fiber for in vivo sampling of ionized acidic pharmaceuticals in fish.
This sampling device exhibited an excellent robustness, reproducibility,
matrix effect-resistant capacity, and quantitative ability. Importantly,
the extraction kinetics of the targeted ionized pharmaceuticals were
significantly accelerated using the device, which significantly improved
the sensitivity of the SPME in vivo sampling method (limits of detection
ranged from 0.12 ng·g<sup>–1</sup> to 0.25 ng·g<sup>–1</sup>) and shorten the sampling time (only 1 min). The
proposed approach was successfully applied to monitor the concentrations
of ionized pharmaceuticals in living fish, which demonstrated that
the device and fiber were suitable for ultrafast in vivo sampling
and continuous monitoring. In addition, the bioconcentration factor
(BCF) values of the pharmaceuticals were derived in tilapia (<i>Oreochromis mossambicus</i>) for the first time, based on the
data of ultrafast in vivo sampling. Therefore, we developed and validated
an effective and ultrafast SPME sampling device for in vivo sampling
of ionized analytes in living organisms and this state-of-the-art
method provides an alternative technique for future in vivo studies
In Situ Hydrothermally Grown TiO<sub>2</sub>@C Core–Shell Nanowire Coating for Highly Sensitive Solid Phase Microextraction of Polycyclic Aromatic Hydrocarbons
Nanostructured
materials have great potential for solid phase microextraction (SPME)
on account of their tiny size, distinct architectures and superior
physical and chemical properties. Herein, a core–shell TiO<sub>2</sub>@C fiber for SPME was successfully fabricated by the simple
hydrothermal reaction of a titanium wire and subsequent amorphous
carbon coating. The readily hydrothermal procedure afforded in situ
synthesis of TiO<sub>2</sub> nanowires on a titanium wire and provided
a desirable substrate for further coating of amorphous carbon. Benefiting
from the much larger surface area of subsequent TiO<sub>2</sub> and
good adsorption property of the amorphous carbon coating, the core–shell
TiO<sub>2</sub>@C fiber was utilized for the SPME device for the first
time and proved to have better performance in extraction of polycyclic
aromatic hydrocarbons. In comparison to the polydimethylsiloxane (PDMS)
and PDMS/divinylbenzene (DVB) fiber for commercial use, the TiO<sub>2</sub>@C fiber obtained gas chromatography responses 3–8
times higher than those obtained by the commercial 100 μm PDMS
and 1–9 times higher than those obtained by the 65 μm
PDMS/DVB fiber. Under the optimized extraction conditions, the low
detection limits were obtained in the range of 0.4–7.1 ng L<sup>–1</sup> with wider linearity in the range of 10–2000
ng L<sup>–1</sup>. Moreover, the fiber was successfully used
for the determination of polycyclic aromatic hydrocarbons in Pearl
River water, which demonstrated the applicability of the core–shell
TiO<sub>2</sub>@C fiber
Study on the Diffusion-Dominated Solid-Phase Microextraction Kinetics in Semisolid Sample Matrix
Solid-phase microextraction (SPME)
kinetics in semisolid samples
should be different from that in aqueous and gaseous samples, as convection
is negligible in semisolid samples but dominates mass transfer in
bulk phases of aqueous and gaseous samples. This study developed a
mathematical model for describing SPME kinetics in semisolid samples
by considering the diffusion of analytes in two compartments, i.e.,
the fiber coating and the ever-increasing diffusion domain in the
sample matrix. The mathematical model predicted that SPME and the
desorption of preloaded analytes from the fiber would be isotropic
in semisolid samples, while SPME in semisolid samples would not follow
the first order kinetics as in aqueous and gaseous samples. The predictions
were proven true in the experiment of four pharmaceuticals in agarose
gel. In return, it was observed in the experiment that SPME kinetics
would deviate more significantly from the first order kinetics for
the analytes with higher partition coefficients between the fiber
and the sample matrix, which was well explained by the mathematical
model developed in this study. In addition, SPME kinetics predicted
by the model coincided well with the experimental results when the
diffusion coefficients were at reasonable levels, which demonstrated
that the model could be satisfactory for describing SPME kinetics
in semisolid samples. The illustration of the nonfirst order SPME
kinetics in semisolid samples can be valuable for evaluating the applicability
of the existing pre-equilibrium calibration methods in semisolid samples
<i>In Vivo</i> Tracing Uptake and Elimination of Organic Pesticides in Fish Muscle
Bioconcentration
factors (BCFs) measured in the laboratory are
important for characterizing the bioaccumulative properties of chemicals
entering the environment, especially the potential persistent organic
pollutants (POPs), which can pose serious adverse effects on ecosystem
and human health. Traditional lethal analysis methods are time-consuming
and sacrifice too many experimental animals. In the present study, <i>in vivo</i> solid-phase microextraction (SPME) was introduced
to trace the uptake and elimination processes of pesticides in living
fish. BCFs and elimination kinetic coefficients of the pesticides
were recorded therein. Moreover, the metabolism of fenthion was also
traced with <i>in vivo</i> SPME. The method was time-efficient
and laborsaving. Much fewer experimental animals were sacrificed during
the tracing. In general, this study opened up an opportunity to measure
BCFs cheaply in laboratories for the registering of emerging POPs
and inspecting of suspected POPs, as well as demonstrated the potential
application of <i>in vivo</i> SPME in the study of toxicokinetics
of pollutants
Observing Discrete Blocking Events at a Polarized Micro- or Submicro-Liquid/Liquid Interface
Single-entity collisional electrochemistry (SECE), a
subfield of
single-entity electrochemistry, enables directly characterizing entities
and particles in the electrolyte solution at the single-entity resolution.
Blockade SECE at the traditional solid ultramicroelectrode (UME)/electrolyte
interface suffers from a limitation: only redox-inactive particles
can be studied. The wide application of the classical Coulter counter
is restricted by the rapid translocation of entities through the orifice,
which results in a remarkable proportion of undetected signals. In
response, the blocking effect of single charged conductive or insulating
nanoparticles (NPs) at low concentrations for ion transfer (IT) at
a miniaturized polarized liquid/liquid interface was successfully
observed. Since the particles are adsorbed at the liquid/liquid interface,
our method also solves the problem of the Coulter counter having a
too-fast orifice translocation rate. The decreasing quantal staircase/step
current transients are from landings (controlled by electromigration)
of either conductive or insulating NPs onto the interface. This interfacial
NP assembly shields the IT flux. The size of each NP can be calculated
by the step height. The particle size measured by dynamic light scattering
(DLS) is used for comparison with that calculated from electrochemical
blocking events, which is in fairly good agreement. In short, the
blocking effect of IT by single entities at micro- or submicro-liquid/liquid
interface has been proven experimentally and is of great reference
in single-entity detection
Polyelectrolyte Microcapsules Dispersed in Silicone Rubber for in Vivo Sampling in Fish Brains
Direct detection
of fluoxetine and its metabolite norfluoxetine
in living fish brains was realized for the first time by using a novel
solid-phase microextraction fiber, which was prepared by mixing the
polyelectrolyte in the oligomer of silicone rubber and followed by
in-mold heat-curing. The polyelectrolyte was finally encased in microcapsules
dispersed in the cured silicone rubber. The fiber exhibited excellent
interfiber reproducibility (5.4–7.1%, <i>n</i> =
6), intrafiber reproducibility (3.7–4.6%, <i>n</i> = 6), and matrix effect-resistant capacity. Due to the capacity
of simultaneously extracting the neutral and the protonated species
of the analytes at physiological pH, the fiber exhibited high extraction
efficiencies to fluoxetine and norfluoxetine. Besides, the effect
of the salinity on the extraction performance and the competitive
sorption between the analytes were also evaluated. Based on the small-sized
custom-made fiber, the concentrations of fluoxetine and norfluoxetine
in the brains of living fish, which were exposed to waterborne fluoxetine
at an environmentally relevant concentration, were determined and
found 4.4 to 9.2 and 5.0 to 9.2 times those in the dorsal-epaxial
muscle. The fiber can be used to detect various protonated bioactive
compounds in living animal tissues
Enhanced Photocatalytic Degradation of Environmental Pollutants under Visible Irradiation by a Composite Coating
Although
nanotechnology has offered effective and efficient solutions for environmental
remediation, the full utilization of sustainable energy and the avoidance
of secondary pollution are still challenges. Herein, we report a two-step
modification strategy for TiO<sub>2</sub> nanoparticles by first forming
a thin, surface-adherent polydopamine (PDA) shell onto the nanoparticles
and then assembling core–shell nanoparticles as a photodegradation
coating. The composite coating modified from TiO<sub>2</sub> could
not only realize the highly efficient utilization of photons from
the visible region but also avoid the secondary pollution of nanoparticles
during application. Additionally, improvements in the adsorption ability
after modification greatly facilitated the photocatalytic process
of the modified materials. A preliminary in vivo study on <i>Daphnia magna</i> and a wastewater treatment experiment suggest
that treatment with the composite coating can effectively eliminate
fluorene and significantly reduce its lethality. We believe the two-step
modification scheme can open new avenues for the facile modification
of nanomaterials for designed purposes, especially in the field of
environmental remediation