The interactions between moisture and materials give rise to the possibility of moisture‐driven energy generation (MEG). Current MEG materials and devices only establish this interaction during water ...sorption in specific configurations, and conversion is eventually ceased by saturated water uptake. This paper reports an asymmetric hygroscopic structure (AHS) that simultaneously achieves energy harvesting and storage from moisture absorption. The AHS is constructed by the asymmetric deposition of a hygroscopic ionic hydrogel over a layer of functionalized carbon. Water absorbed from the air creates wet‐dry asymmetry across the AHS and hence an in‐plane electric field. The asymmetry can be perpetually maintained even after saturated water absorption. The absorbed water triggers the spontaneous development of an electrical double layer (EDL) over the carbon surface, which is termed a hygro‐ionic process, accounting for the capacitive properties of the AHS. A peak power density of 70 µW cm‐3 was realized after geometry optimization. The AHS shows the ability to be recharged either by itself owing to a self‐regeneration effect or via external electrical means, which allows it to serve as an energy storage device. In addition to insights into moisture‐material interaction, AHSs further shows potential for electronics powering in assembled devices.
An unusual route for moisture‐driven energy generation (MEG) is proposed by an asymmetric hygroscopic structure (AHS), which simultaneously achieves MEG and energy storage. The water‐absorption triggered dual function originates from the permanently maintained wet‐dry asymmetry that is formed across the AHS by the asymmetric deposition of a hygroscopic ionic hydrogel over a functionalized‐carbon layer.
Transcription of new RNA is crucial for maintaining synaptic plasticity, learning and memory. Although the importance of synaptic plasticity-related messenger RNAs (mRNAs) is well established, the ...role of a large group of long non-coding RNAs (lncRNAs) in long-term potentiation (LTP) is not known. In this study, we demonstrated the expression of a lncRNA cluster, namely maternally expressed gene 3 (
), retrotransposon-like gene 1-anti-sense (
),
and
, which is located in the maternally imprinted
region on mouse chromosome 12qF1, in primary cortical neurons following glycine stimulation in an N-Methyl-D-aspartate receptor (NMDAR)-dependent manner. Importantly, we also validated the expression of
,
and
in the hippocampus of mice following cued fear conditioning
. Interestingly,
is the only lncRNA that is expressed in the nucleus and cytoplasm. Further analysis revealed that
loss of function blocked the glycine-induced increase of the GluA1 subunit of AMPA receptors on the plasma membrane, a major hallmark of LTP. This aberrant trafficking of AMPA receptors correlated with the dysregulation of the phosphatidylinoside-3-kinase (PI3K)/AKT signaling pathway and the downregulation of the lipid phosphatase and tensin homolog (PTEN). These findings provide the first evidence for a functional role of the lncRNA
in the intricate regulation of the PTEN/PI3K/AKT signaling cascade during synaptic plasticity in neurons.
Incorporation of fluorinated moieties in polymeric nanoparticles has been shown in many instances to increase their uptake by living cells and, hence, has proven to be a useful approach to enhancing ...delivery to cells. However, it remains unclear how incorporation of fluorine affects critical transport processes, such as interactions with membranes, intracellular transport, and tumor penetration. In this study, we investigate the influence of fluorine on transport properties using a series of rationally designed poly(oligo(ethylene glycol) methyl ether acrylate)-
-perfluoropolyether (poly(OEGA)
-PFPE) copolymers. Copolymers with different fluorine contents were prepared and exhibit aggregate in solution in a manner dependent on the fluorine content. Doxorubicin-conjugated poly(OEGA)
-PFPE nanoparticles with lower fluorine content exist in solution as unimers, leading to greater exposure of hydrophobic PFPE segments to the cell surface. This, in turn, results in greater cellular uptake, deeper tumor penetration, as well as enhanced therapeutic efficacy compared to that with the micelle-state nanoaggregates (poly(OEGA)
-PFPE and poly(OEGA)
-PFPE) with higher fluorine content but with less PFPE exposed to the cell membranes. Our results demonstrate that the aggregation behavior of these fluorinated polymers plays a critical role in internalization and transport in living cells and 3D spheroids, providing important design criteria for the preparation of highly effective delivery agents.
Chondrogenesis of mesenchymal stem cells (MSCs) is typically induced when they are condensed into a single aggregate and exposed to transforming growth factor-β (TGF-β). Hypoxia, like aggregation and ...TGF-β delivery, may be crucial for complete chondrogenesis. However, the pellet dimensions and associated self-induced oxygen gradients of current chondrogenic methods may limit the effectiveness of in vitro differentiation and subsequent therapeutic uses. Here we describe the use of embryoid body-forming technology to produce microscopic aggregates of human bone marrow MSCs (BM-MSCs) for chondrogenesis. The use of micropellets reduces the formation of gradients within the aggregates, resulting in a more homogeneous and controlled microenvironment. These micropellet cultures (~170 cells/micropellet) as well as conventional pellet cultures (~2 × 105 cells/pellet) were chondrogenically induced under 20% and 2% oxygen environments for 14 days. Compared to conventional pellets under both environments, micropellets differentiated under 2% O2 showed significantly increased sulfated glycosaminoglycan (sGAG) production and more homogeneous distribution of proteoglycans and collagen II. Aggrecan and collagen II gene expressions were increased in pellet cultures differentiated under 2% O2 relative to 20% O2 pellets but 2% O2 micropellets showed even greater increases in these genes, as well as increased SOX9. These results suggest a more advanced stage of chondrogenesis in the micropellets accompanied by more homogeneous differentiation. Thus, we present a new method for enhancing MSC chondrogenesis that reveals a unique relationship between oxygen tension and aggregate size. The inherent advantages of chondrogenic micropellets over a single macroscopic aggregate should allow for easy integration with a variety of cartilage engineering strategies.
...in this article, we explore existing tissue engineering technologies for de novo HF regeneration and delivery, which could potentially be used as in vitro organoid models to study the effects of ...future drug delivery. Restoring positional relationships of hair follicular cell composites Previous in vivo HF reconstitution assays have demonstrated that co-grafted dissociated epithelial and dermal cells re-position themselves spontaneously to imitate their anatomical relationship in vivo, suggesting the importance of the positional relationship between epithelial and mesenchymal cells in HFs toward follicular morphogenesis and epithelial-mesenchymal interactions (20). ...artificially assembling cell composites mimicking the HF bulb structure instead of using dissociated cells has been proposed to enhance epithelial-mesenchymal interactions. Tan JJY, Pan J, Sun L, Zhang J, Wu C, Kang L. Bioactives in Chinese proprietary medicine modulates 5α-reductase activity and gene expression associated with androgenetic alopecia. Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Hair follicle morphogenesis is heavily dependent on reciprocal, sequential, and epithelial-mesenchymal interaction (EMI) between epidermal stem cells and the specialized cells of the underlying ...mesenchyme, which aggregate to form the dermal condensate (DC) and will later become the dermal papilla (DP). Similar models were developed with a co-culture of keratinocytes and DP cells. Previous studies have demonstrated that co-culture with keratinocytes maintains the in vivo characteristics of the DP. However, it is often challenging to develop three-dimensional (3D) DP and keratinocyte co-culture models for long term in vitro studies, due to the poor intercellular adherence between keratinocytes. Keratinocytes exhibit exfoliative behavior, and the integrity of the DP and keratinocyte co-cultured spheroids cannot be maintained over prolonged culture. Short durations of culture are unable to sufficiently allow the differentiation and re-programming of the keratinocytes into hair follicular fate by the DP. In this study, we explored a microgel array approach fabricated with two different hydrogel systems. Using poly (ethylene glycol) diacrylate (PEGDA) and gelatin methacrylate (GelMA), we compare their effects on maintaining the integrity of the cultures and their expression of important genes responsible for hair follicle morphogenesis, namely
,
, and
, over prolonged duration. We discovered that low attachment surfaces such as PEGDA result in the exfoliation of keratinocytes and were not suitable for long-term culture. GelMA, on the hand, was able to sustain the integrity of co-cultures and showed higher expression of the morphogens overtime.
Donning of personal protective equipment (PPE) in the healthcare sector has been intensified by the on‐going COVID‐19 pandemic around the globe. While extensive PPE provides protection, it typically ...limits moisture permeability and severely hinders the sweat evaporation process, resulting in greater heat stress on the personnel. Herein, a zinc‐poly(vinyl alcohol) (Zn‐PVA) composite film is fabricated by embedding a super‐hygroscopic zinc‐ethanolamine complex (Zn‐complex) in the PVA matrix. By attaching the Zn‐PVA composite film, the relative humidity (RH) inside the protective suit decreases from 91.0% to 48.2%. The reduced RH level, in turn, enhances evaporative cooling, hence bringing down the heat index from 64.6 to 40.0 °C at an air temperature of 35 °C, remarkably lowering the likelihood of heat stroke. The American Society for Testing and Materials tests conducted on a sweating manikin have also proven that the Zn‐PVA composite films can significantly reduce the evaporative resistance of the protective suit by 90%. The low material cost, facile fabrication process, and reusability allow the Zn‐PVA composition films to be readily available for healthcare workers worldwide. This application can be further extended to other occupations that are facing severe thermal discomfort and heat stress.
A super‐hygroscopic zinc‐poly(vinyl alcohol) composite film is developed to improve thermal comfort for healthcare workers. With the composite film attached to the personal protective equipment, the water vapor accumulated is rapidly absorbed by the film. A steep vapor pressure gradient is created to facilitate sweat evaporation and relieve the heat stress experienced by healthcare workers.
In vitro 3D cell models have been accepted to better recapitulate aspects of in vivo organ environment than 2D cell culture. Currently, the production of these complex in vitro 3D cell models with ...multiple cell types and microenvironments remains challenging and prone to human error. Here, a versatile ink comprising a 4‐arm poly(ethylene glycol) (PEG)‐based polymer with distal maleimide derivatives as the main ink component and a bis‐thiol species as the activator that crosslinks the polymer to form the hydrogel in less than a second is reported. The rapid gelation makes the polymer system compatible with 3D bioprinting. The ink is combined with a novel drop‐on‐demand 3D bioprinting platform, designed specifically for producing 3D cell cultures, consisting of eight independently addressable nozzles and high‐throughput printing logic for creating complex 3D cell culture models. The combination of multiple nozzles and fast printing logic enables the rapid preparation of many complex 3D cell cultures comprising multiple hydrogel environments in one structure in a standard 96‐well plate format. The platform's compatibility for biological applications is validated using pancreatic ductal adenocarcinoma cancer (PDAC) and human dermal fibroblast cells with their phenotypic responses controlled by tuning the hydrogel microenvironment.
3D cell culture has been proven to better mimic physiological conditions than 2D. Production throughput and assay consistency remain the bottleneck for the rapid uptake of in vitro 3D cell culture models. The combination of tunable synthetic hydrogel and rapid drop‐on‐demand bioprinting is demonstrated as a potential solution to democratize in vitro 3D cell culture models among biologists.
Cost‐effective expansion of human mesenchymal stem/stromal cells (hMSCs) remains a key challenge for their widespread clinical deployment. Fibroblast growth factor‐2 (FGF‐2) is a key hMSC mitogen ...often supplemented to increase hMSC growth rates. However, hMSCs also produce endogenous FGF‐2, which critically interacts with cell surface heparan sulfate (HS). We assessed the interplay of FGF‐2 with a heparan sulfate variant (HS8) engineered to bind FGF‐2 and potentiate its activity. Bone marrow‐derived hMSCs were screened in perfused microbioreactor arrays (MBAs), showing that HS8 (50 μg/ml) increased hMSC proliferation and cell number after 3 days, with an effect equivalent to FGF‐2 (50 ng/ml). In combination, the effects of HS8 and FGF‐2 were additive. Differential cell responses, from upstream to downstream culture chambers under constant flow of media in the MBA, provided insights into modulation of FGF‐2 transport by HS8. HS8 treatment induced proliferation mainly in the downstream chambers, suggesting a requirement for endogenous FGF‐2 accumulation, whereas responses to FGF‐2 occurred primarily in the upstream chambers. Adding HS8 along with FGF‐2, however, maximized the range of FGF‐2 effectiveness. Measurements of FGF‐2 in static cultures then revealed that this was because HS8 caused increased endogenous FGF‐2 production and liberated FGF‐2 from the cell surface into the supernatant. HS8 also sustained levels of supplemented FGF‐2 available over 3 days. These results suggest HS8 enhances hMSC proliferation and expansion by leveraging endogenous FGF‐2 production and maximizing the effect of supplemented FGF‐2. This is an exciting strategy for cost‐effective expansion of hMSCs. Stem Cells Translational Medicine 2017;6:1178–1190
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