23 research outputs found
A Sunlight-Degradable Autonomous Self-Healing Supramolecular Elastomer for Flexible Electronic Devices
Preparing an autonomous
self-healing supramolecular elastomer with
sunlight degradability is still a challenging task in related fields.
In this work, we report a supramolecular elastomer by using the classic
host–guest complexation of visible-light-photolabile picolinium-containing
adamantanes (Ad) and β-cyclodextrin nanogels (β-CD). The
as-synthesized elastomer possesses merits of high mechanical strength,
excellent stretchability (>1500% strain), efficient self-healing
(>85% at 60 min), ultrastability against electrolytes, and photodegradation
properties, implying versatile applications in flexible and stretchable
electronics. As proofs-of-concept, self-healable strain and pressure
sensors using conductive elastomers are first fabricated, which feature
exceptionally high sensitivity (e.g., 0.1% in capacitance at 0.2 kPa)
and fast response to detect human body motions. A degradable and flexible
supercapacitor is also fabricated using the conductive elastomer as
the flexible matrix. Remarkably, both the elastomer and this supercapacitor
can be degraded upon the exposure to sunlight irradiation in 48 h
at very mild conditions. Therefore, it is anticipated that such a
novel strategy and the as-prepared supramolecular elastomer can inspire
further applications in the multidisciplinary fields of materials
science, electronics, etc
A Sunlight-Degradable Autonomous Self-Healing Supramolecular Elastomer for Flexible Electronic Devices
Preparing an autonomous
self-healing supramolecular elastomer with
sunlight degradability is still a challenging task in related fields.
In this work, we report a supramolecular elastomer by using the classic
host–guest complexation of visible-light-photolabile picolinium-containing
adamantanes (Ad) and β-cyclodextrin nanogels (β-CD). The
as-synthesized elastomer possesses merits of high mechanical strength,
excellent stretchability (>1500% strain), efficient self-healing
(>85% at 60 min), ultrastability against electrolytes, and photodegradation
properties, implying versatile applications in flexible and stretchable
electronics. As proofs-of-concept, self-healable strain and pressure
sensors using conductive elastomers are first fabricated, which feature
exceptionally high sensitivity (e.g., 0.1% in capacitance at 0.2 kPa)
and fast response to detect human body motions. A degradable and flexible
supercapacitor is also fabricated using the conductive elastomer as
the flexible matrix. Remarkably, both the elastomer and this supercapacitor
can be degraded upon the exposure to sunlight irradiation in 48 h
at very mild conditions. Therefore, it is anticipated that such a
novel strategy and the as-prepared supramolecular elastomer can inspire
further applications in the multidisciplinary fields of materials
science, electronics, etc
Unexpected Temperature-Dependent Single Chain Mechanics of Poly(<i>N</i>-isopropyl-acrylamide) in Water
PolyÂ(<i>N</i>-isopropyl-acrylamide) (PNIPAM)
is a paradigm
thermally sensitive polymer, which has a lower critical solution temperature
(LCST) of ∼32 °C in water. Herein by AFM-based single molecule
force spectroscopy (SMFS), we measured the single chain elasticity
of PNIPAM across the LCST in water. Below LCST, the force curves obtained
at different temperatures have no remarkable difference; while above
LCST, an unexpected temperature dependent elasticity is observed,
mainly in the middle force regime. We found that 35 °C is a turning
point of the variation: from 31 to 35 °C, the middle parts of
the force curves drop gradually, whereas from 35 to 40 °C, the
middle parts rise gradually. A possible mechanism for the unexpected
temperature dependent mechanics is proposed. The single chain contraction against external force upon heating from 35 to 40 °C
may cast new light on the design of molecular devices that convert
thermal energy to mechanical work
Down-Regulated Receptor Interacting Protein 140 Is Involved in Lipopolysaccharide-Preconditioning-Induced Inactivation of Kupffer Cells and Attenuation of Hepatic Ischemia Reperfusion Injury
<div><p>Background</p><p>Lipopolysaccharide (LPS) preconditioning is known to attenuate hepatic ischemia/reperfusion injury (I/RI); however, the precise mechanism remains unclear. This study investigated the role of receptor-interacting protein 140 (RIP140) on the protective effect of LPS preconditioning in hepatic I/RI involving Kupffer cells (KCs).</p><p>Methods</p><p>Sprague—Dawley rats underwent 70% hepatic ischemia for 90 minutes. LPS (100 μg/kg) was injected intraperitoneally 24 hours before ischemia. Hepatic injury was observed using serum and liver samples. The LPS/NF-κB (nuclear factor-κB) pathway and hepatic RIP140 expression in isolated KCs were investigated.</p><p>Results</p><p>LPS preconditioning significantly inhibited hepatic RIP140 expression, NF-κB activation, and serum proinflammatory cytokine expression after I/RI, with an observation of remarkably reduced serum enzyme levels and histopathologic scores. Our experiments showed that protection effects could be effectively induced in KCs by LPS preconditioning, but couldn’t when RIP140 was overexpressed in KCs. Conversely, even without LPS preconditioning, protective effects were found in KCs if RIP140 expression was suppressed with siRNA.</p><p>Conclusions</p><p>Down-regulated RIP140 is involved in LPS-induced inactivation of KCs and hepatic I/RI attenuation.</p></div
Protein Crystallization-Mediated Self-Strengthening of High-Performance Printable Conducting Organohydrogels
Conductive polymers have many advanced
applications,
but there
is still an important target in developing a general and straightforward
strategy for printable, mechanically stable, and durable organohydrogels
with typical conducting polymers of, for example, polypyrrole, polyaniline,
or poly(3,4-ethylenedioxythiophene). Here we report a protein crystallization-mediated
self-strengthening strategy to fabricate printable conducting organohydrogels
with the combination of rational photochemistry design. Such organohydrogels
are one-step prepared via rapidly and orthogonally controllable photopolymerizations
of pyrroles and gelatin protein in tens of seconds. As-prepared conducting
organohydrogels are patterned and printed to complicated structures
via shadow-mask lithography and 3D extrusion technology. The mild
photocatalytic system gives the transition metal carbide/nitride (MXene)
component high stability during the oxidative preparation process
and storage. Controlling water evaporation promotes gelatin crystallization
in the as-prepared organohydrogels that significantly self-strengthens
their mechanical property and stability in a broad temperature range
and durability against continuous friction treatment without introducing
guest functional materials. Also, these organohydrogels have commercially
electromagnetic shielding, thermal conducting properties, and temperature-
and light-responsibility. To further demonstrate the merits of this
simple strategy and as-prepared organohydrogels, prism arrays, as
proofs-of-concept, are printed and applied to make wearable triboelectric
nanogenerators. This self-strengthening process and 3D-printability
can greatly improve their voltage, charge, and current output performances
compared to the undried and flat samples
The influence of LPS preconditioning dose on hepatic ischemia/reperfusion injury.
<p>Animals subjected to 90 minutes of 70% hepatic ischemia, followed by 6 h reperfusion, then the hepatic I/RI was evaluated. <b>(A)</b> The H&E staining of the liver from sham group, LPS + I/RI group and I/RI group. <b>(B)</b> ALT serum level. <b>(C)</b> Suzuki’s pathological score (*, <i>P</i> < 0.01).</p
The influence of LPS on RIP140 expression of KCs.
<p>The RIP140 knockdown and overexpression in KCs were assessed using RT-PCR and WB <b>(A)</b>. KC RIP140 expression was examined with RT-PCR, western blot <b>(B)</b>, and immunofluorescence assay <b>(C)</b> (<i>*</i>, <i>P</i> < 0.01).</p
Synthetic Glycopolymers for Highly Efficient Differentiation of Embryonic Stem Cells into Neurons: Lipo- or Not?
To
realize the potential application of embryonic stem cells (ESCs) for
the treatment of neurodegenerative diseases, it is a prerequisite
to develop an effective strategy for the neural differentiation of
ESCs so as to obtain adequate amount of neurons. Considering the efficacy
of glycosaminoglycans (GAG) and their disadvantages (e.g., structure
heterogeneity and impurity), GAG-mimicking glycopolymers (designed
polymers containing functional units similar to natural GAG) with
or without phospholipid groups were synthesized in the present work
and their ability to promote neural differentiation of mouse ESCs
(mESCs) was investigated. It was found that the lipid-anchored GAG-mimicking
glycopolymers (lipo-pSGF) retained on the membrane of mESCs rather
than being internalized by cells after 1 h of incubation. Besides,
lipo-pSGF showed better activity in promoting neural differentiation.
The expression of the neural-specific maker β3-tubulin in lipo-pSGF-treated
cells was ∼3.8- and ∼1.9-fold higher compared to natural
heparin- and pSGF-treated cells at day 14. The likely mechanism involved
in lipo-pSGF-mediated neural differentiation was further investigated
by analyzing its effect on fibroblast growth factor 2 (FGF2)-mediated
extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling
pathway which is important for neural differentiation of ESCs. Lipo-pSGF
was found to efficiently bind FGF2 and enhance the phosphorylation
of ERK1/2, thus promoting neural differentiation. These findings demonstrated
that engineering of cell surface glycan using our synthetic lipo-glycopolymer
is a highly efficient approach for neural differentiation of ESCs
and this strategy can be applied for the regulation of other cellular
activities mediated by cell membrane receptors
Protein Crystallization-Mediated Self-Strengthening of High-Performance Printable Conducting Organohydrogels
Conductive polymers have many advanced
applications,
but there
is still an important target in developing a general and straightforward
strategy for printable, mechanically stable, and durable organohydrogels
with typical conducting polymers of, for example, polypyrrole, polyaniline,
or poly(3,4-ethylenedioxythiophene). Here we report a protein crystallization-mediated
self-strengthening strategy to fabricate printable conducting organohydrogels
with the combination of rational photochemistry design. Such organohydrogels
are one-step prepared via rapidly and orthogonally controllable photopolymerizations
of pyrroles and gelatin protein in tens of seconds. As-prepared conducting
organohydrogels are patterned and printed to complicated structures
via shadow-mask lithography and 3D extrusion technology. The mild
photocatalytic system gives the transition metal carbide/nitride (MXene)
component high stability during the oxidative preparation process
and storage. Controlling water evaporation promotes gelatin crystallization
in the as-prepared organohydrogels that significantly self-strengthens
their mechanical property and stability in a broad temperature range
and durability against continuous friction treatment without introducing
guest functional materials. Also, these organohydrogels have commercially
electromagnetic shielding, thermal conducting properties, and temperature-
and light-responsibility. To further demonstrate the merits of this
simple strategy and as-prepared organohydrogels, prism arrays, as
proofs-of-concept, are printed and applied to make wearable triboelectric
nanogenerators. This self-strengthening process and 3D-printability
can greatly improve their voltage, charge, and current output performances
compared to the undried and flat samples
The influence of LPS preconditioning on RIP140 expression and NF-κB signal transduction.
<p>Hepatic RIP140 expression in the rats from different groups was examined with immunohistochemical analysis <b>(A)</b>, RT-PCR <b>(B)</b>, and western blot <b>(C)</b>. Hepatic NF-κB activity <b>(D)</b>, and TNF-α, IL-1β, and IL-6 expression levels <b>(E)</b> were examined with ELISA and RT-PCR (*, <i>P</i> < 0.01).</p