In recent years, cardiac patches have been developed for the treatment of myocardial infarction. However, the fixation approaches onto the tissue through suture or phototriggered reaction inevitably cause new tissue damage. Herein, a paintable hydrogel is constructed based on Fe -triggered simultaneous polymerization of covalently linked pyrrole and dopamine in the hyperbranched chains where the in situ formed conductive polypyrrole also uniquely serves to crosslink network. This conductive and adhesive hydrogel can be conveniently painted as a patch onto the heart surface without adverse liquid leakage. The functional patch whose conductivity is equivalent to that of normal myocardium is strongly bonded to the beating heart within 4 weeks, accordingly efficiently boosting the transmission of electrophysiological signals. Eventually, the reconstruction of cardiac function and revascularization of the infarct myocardium are remarkably improved. The translatable suture-free strategy reported in this work is promising to address the human clinical challenges in cardiac tissue engineering.
The
continued growth in the demand of data storage and processing
has spurred the development of high-performance storage technologies
and brain-inspired neuromorphic hardware. Semiconductor quantum dots
(QDs) offer an appealing option for these applications since they
combine excellent electronic/optical properties and structural stability
and can address the requirements of low-cost, large-area, and solution-based
manufactured technologies. Here, we focus on the development of nonvolatile
memories and neuromorphic computing systems based on QD thin-film
solids. We introduce recent advances of QDs and highlight their unique
electrical and optical features for designing future electronic devices.
We also discuss the advantageous traits of QDs for novel and optimized
memory techniques in both conventional flash memories and emerging
memristors. Then, we review recent advances in QD-based neuromorphic
devices from artificial synapses to light-sensory synaptic platforms.
Finally, we highlight major challenges for commercial translation
and consider future directions for the postsilicon era.
Hydrogen sulfide
(H2S) exhibits extensive protective
actions in cardiovascular systems, such as anti-inflammatory and stimulating
angiogenesis, but its therapeutic potential is severely discounted
by the short half-life and the poorly controlled releasing behavior.
Herein, we developed a macromolecular H2S prodrug by grafting
2-aminopyridine-5-thiocarboxamide (a small-molecule H2S
donor) on partially oxidized alginate (ALG-CHO) to mimic the slow
and continuous release of endogenous H2S. In addition,
tetraaniline (a conductive oligomer) and adipose-derived stem cells
(ADSCs) were introduced to form a stem cell-loaded conductive H2S-releasing hydrogel through the Schiff base reaction between
ALG-CHO and gelatin. The hydrogel exhibited adhesive property to ensure
a stable anchoring to the wet and beating hearts. After myocardial
injection, longer ADSCs retention period and elevated sulfide concentration
in rat myocardium were demonstrated, accompanied by upregulation of
cardiac-related mRNA (Cx43, α-SMA, and cTnT) and angiogenic
factors (VEGFA and Ang-1) and downregulation of inflammatory factors
(tumor necrosis factor-α). Echocardiography and histological
analysis strongly demonstrated an increase in the ejection fraction
value and smaller infarction size, suggesting a remarkable improvement
of the cardiac functions of Sprague-Dawley rats. The ADSC-loaded conductive
hydrogen sulfide-releasing hydrogel dramatically promoted the therapeutic
effects, offering a promising therapeutic strategy for treating myocardial
infarction.
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