Abstract The photothermal conversion capacity of pristine organic phase change materials (PCMs) is inherently insufficient in solar energy utilization. To upgrade their photothermal conversion capacity, we developed bimetallic zeolitic imidazolate framework (ZIF) derived Co/N co‐doped flower‐like carbon (Co/N‐FLC)‐based composite PCMs toward solar energy harvesting. 3D interconnected carbon framework with low interfacial thermal resistance, abundant carbon defects and high content of nitrogen doping, excellent localized surface plasmon resonance (LSPR) effect of Co nanoparticles, and light absorber Co 3 ZnC in Co/N‐FLC synergistically upgrade the photothermal capacity of (polyethylene glycol) PEG@Co/N‐FLC composite PCMs with an ultrahigh photothermal conversion efficiency of 94.8% under 0.16 W/cm 2 . Uniformly anchored Co and Co 3 ZnC nanoparticles in carbon framework guarantee excellent photon capture ability. Bridging carbon nanotubes (CNTs) in 2D carbon nanosheets further accelerate the rapid transport of phonons by constructing cross‐connected heat transfer paths. Additionally, PEG@Co/N‐FLC exhibits a thermal energy storage density of 100.69 J/g and excellent thermal stability and durable reliability. Therefore, PEG@Co/N‐FLC composite PCMs are promising candidates to accelerate the efficient utilization of solar energy.
A spatiotemporally dynamic therapy (SDT) is proposed as a powerful therapeutic modality that provides spatially dynamic responses of drug-carriers for adapting to the wound microenvironment. Herein, dynamic chitosan-poly (ethylene glycol) (CP) Schiff-base linkages are employed to perform SDT by directly converting a liquid drug
In this work, we develop a modified mussel-inspired method to enhance interfacial adhesion of aramid fiber to a rubber matrix. Through a simple dip-coating procedure, catechol and polyamine could initially codeposit as a poly(catechol-polyamine) (PCPA) coating on the surface of the aramid fiber. Then, the PCPA layer could be further grafted with silane coupling agent γ-(glycidyloxypropyltrimethoxysilane) (GPTMS). Results indicated that GPTMS was successfully grafted onto the aramid fiber surface via the bridging of the PCPA layer. The interfacial adhesion between the aramid fibers and the rubber matrix was improved compared to that achieved by polydopamine in our previous study. In addition, this method is more applicable to the rubber industry than polydopamine coating because of its cost-effectiveness and short reaction time.
Hsp70 response serves as an important mechanism underlying skeletal muscle adaptation to cellular stress. Electrical stimulation (ES) is frequently used to investigate muscle response to cellular stress, and ES can bring out a series of functional and structural responses in the skeletal muscle, which varies with characteristics of ES. It is yet unknown whether there is an Hsp70 response in the ES-induced cellular process. PURPOSE: To investigate whether ES induces Hsp70 responses in C2/C12 and the Hsp70 response depends on different kinds of ES. METHODS: Cultured C2C12 (by a confluence at 75%) were divided into different groups with regard to ES characteristics (at 13 voltages): A (ES: 12 Hz, 11 min), B (12 Hz, 90 min) and C (100 Hz, 11 min). Cells were harvested before ES, and 0, 1, 4, 8, 12h after ES. The gene expression of Hsp70 was estimated by real-time quantitative PCR with relation to an internal reference (ß2-microglobulin), and Hsp70 expression at protein level was also determined by quantitative Western-Blot. The results were analysed in comparison with control cells without ES. RESULTS: Hsp70 mRNA increased 1h after ES in all the groups (142% to 229%), and 4h after ES it increased further clearly in B (386%) and C (1412%). 8h after ES the increase maintained in B (389%). 12h after ES it kept above baseline in B(246%) and C (310%). Regarding Hsp70 protein expression, there was a significant and continual increase in B during first 8 hours after ES, reaching peak (412%) at 8h, and then dropped to 213% 12h after ES. In comparison, Hsp70 protein expression increased slightly 8h after ES in A (127%) and C (149%), but not at other time points after ES. CONCLUSION: Electrical stimulation to C2/C12 led to distinct Hsp70 response at both mRNA and protein level, which associated with characteristics of ES. Not only the duration of ES, but also the frequency of ES could significantly affect the Hsp70 response. There was a discrepancy in Hsp70 response in the ES-stimulated cells between mRNA and protein level, suggesting possible different regulation at transcriptional and translational level in the Hsp70 response. The role of Hsp70 in the experimental setting has to be studied further.
Despite advances in wound treatments, chronic diabetic wounds remain a significant medical challenge. Exosomes from mesenchymal stem cells (MSCs) and small molecule activators of nuclear factor erythroid 2-related factor 2 (Nrf2) have emerged as potential therapies for nonhealing diabetic wounds. This study aimed to evaluate the effects of exosomes from bone marrow-derived MSCs (BMSCs) alone, or in combination with a small molecule activator of Nrf2 on diabetic wound healing.BMSCs and endothelial progenitor cells (EPCs) were isolated from the femur and tibia bone marrow of Sprague-Dawley (SD) rats and culture-expanded. Exosomes were harvested from the BMSC culture supernatants through ultracentrifugation. The effects of the exosomes and Nrf2 knockdown, alone or in combination, on EPC tube formation were evaluated. Streptozotocin-induced diabetic rats bearing a fresh full-thickness round wound were treated with the exosomes alone, or in combination with a lentiviral shRNA targeting Nrf2 (Lenti-sh-Nrf2) or tert-butylhydroquinone (tBHQ), a small molecule activator of Nrf2. Two weeks later, wound closure, re-epithelization, collagen deposition, neovascularization, and local inflammation were evaluated. BMSC exosomes promoted while Nrf2 knockdown inhibited EPC tube formation. BMSC exosomes accelerated wound closure, re-epithelization, collagen deposition, and neovascularization, and reduced wound inflammation in diabetic rats. These regenerative and anti-inflammatory effects of the exosomes were inhibited by Lenti-sh-Nrf2 but enhanced by tBHQ administration.BMSC exosomes in combination with a small molecule Nrf2 activator hold promise as a new therapeutic option for chronic diabetic wounds.
Hydrogels composed of hyperbranched poly(amine-ester) (HPAE) macromers with 36% of terminal CC groups were prepared as a pH-sensitive multi-drug release system with low swelling ratios (4.2% for the lowest one). Anticancer drugs including doxorubicin hydrochloride (Dox), 5-fluorouracil (5FU) and hydroxycamptothecin (HPT) were separately encapsulated in HPAE macromers before hydrogel formation and their release can be controlled by the conformational change of HPAE macromers under different pH conditions, fast when pH > 7 and slow when pH < 7. Furthermore, this system allows a combination release of multiple drugs and the release behavior of each drug was relatively independent with no interference from each other. This is different from traditional pH-sensitive hydrogel systems which control the drug release by a swelling-shrinking mechanism. HPAE hydrogels exhibited pH-controllable drug release properties with a relatively constant volume, because the swelling of hydrogel is limited due to the unique globe like structure of HPAE molecules. These findings show the great promise of HPAE hydrogels as a smart release system for controlled delivery of single or multiple drugs in combined therapy, and where a constant volume of the release system is required.
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