Enzyme-Modulated Anaerobic Encapsulation of Chlorella Cells Allows Switching from O2 to H2 Production.

Single-cell encapsulation has become an effective strategy in cell surface engineering; however, the construction of cell wall-like layers that allow the switching of the inherent functionality of the engineered cell is still rare. In this study, we show a universal way to create an enzyme-modulated oxygen-consuming sandwich-like layer by using polydopamine, laccase, and tannic acid as building blocks, which then could generate an anaerobic microenvironment around the cell. This layer protected the encapsulated C. pyrenoidosa cell against external stresses and enabled it to switch from normal photosynthetic O2 production to photobiological H2 production. The layer showed an smaller effect on the PSII activity, which contributed a significant enhancement on the rate (0.32 µmol H2 h-1 (mg chlorophyll)-1 ) and the duration (7 d) of H2 production. This strategy is expected to provide a pathway for modulating the functionality of cells and for breakthroughs in the development of green energy alternatives.

Gypenoside inhibits RANKL-induced osteoclastogenesis by regulating NF-κB, AKT, and MAPK signaling pathways.

Gypenoside (GP) is one of the most pharmacologically active components in Gynostemma pentaphyllum and possesses neuroprotective, anticancer, anti-oxidant, anti-inflammatory, anti-diabetic, and anti-osteoarthritis effects. However, the involvement of GP the osteoclast differentiation has not yet been investigated. In the present study, we examined the effect of GP on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation. Our results demonstrated that GP significantly inhibited the formation of osteoclast, as well as suppressed the expression of osteoclastogenesis-related marker proteins in RANKL-stimulated bone marrow macrophages (BMMs). For molecular mechanisms, GP inhibited RANKL-induced NF-κB and MAPK activation and AKT phosphorylation in BMMs. Collectively, these findings suggest that GP inhibits RANKL-induced osteoclastogenesis via regulating NF-κB, AKT, and MAPK signaling pathways. Therefore, GP may be a potential agent in the treatment of osteoclast-related diseases such as osteoporosis.

Folic acid functionalized silver nanoparticles with sensitivity and selectivity colorimetric and fluorescent detection for Hg2+ and efficient catalysis.

In this research, folic acid functionalized silver nanoparticles (FA-AgNPs) were selected as a colorimetric and a 'turn on' fluorescent sensor for detecting Hg(2+). After being added into Hg(2+), AgNPs can emit stable fluorescence at 440 nm when the excitation wavelength is selected at 275 nm. The absorbance and fluorescence of the FA-AgNPs could reflect the concentration of the Hg(2+) ions. Thus, we developed a simple, sensitive analytical method to detect Hg(2+) based on the colorimetric and fluorescence enhancement of FA-AgNPs. The sensor exhibits two linear response ranges between absorbance and fluorescence intensity with Hg(2+) concentration, respectively. Meanwhile, a detection limit of 1 nM is estimated based on the linear relationship between responses with a concentration of Hg(2+). The high specificity of Hg(2+) with FA-AgNPs interactions provided the excellent selectivity towards detecting Hg(2+) over other metal ions (Pb(2+), Mg(2+), Zn(2+), Ni(2+), Cu(2+), Co(2+), Ca(2+), Mn(2+), Fe(2+), Cd(2+), Ba(2+), Cr(6+) and Cr(3+)). This will provide a simple, effective and multifunctional colorimetric and fluorescent sensor for on-site and real-time Hg(2+) ion detection. The proposed method can be applied to the analysis of trace Hg(2+) in lake water. Additionally, the FA-AgNPs can be used as efficient catalyst for the reduction of 4-nitrophenol and potassium hexacyanoferrate (III).

An Artificial Neural Network Based on Oxide Synaptic Transistor for Accurate and Robust Image Recognition.

Synaptic transistors with low-temperature, solution-processed dielectric films have demonstrated programmable conductance, and therefore potential applications in hardware artificial neural networks for recognizing noisy images. Here, we engineered AlOx/InOx synaptic transistors via a solution process to instantiate neural networks. The transistors show long-term potentiation under appropriate gate voltage pulses. The artificial neural network, consisting of one input layer and one output layer, was constructed using 9 × 3 synaptic transistors. By programming the calculated weight, the hardware network can recognize 3 × 3 pixel images of characters z, v and n with a high accuracy of 85%, even with 40% noise. This work demonstrates that metal-oxide transistors, which exhibit significant long-term potentiation of conductance, can be used for the accurate recognition of noisy images.

Review: Application of Bionic-Structured Materials in Solid-State Electrolytes for High-Performance Lithium Metal Batteries.

Solid-state lithium metal batteries (SSLMBs) have gained significant attention in energy storage research due to their high energy density and significantly improved safety. But there are still certain problems with lithium dendrite growth, interface stability, and room-temperature practicality. Nature continually inspires human development and intricate design strategies to achieve optimal structural applications. Innovative solid-state electrolytes (SSEs), inspired by diverse natural species, have demonstrated exceptional physical, chemical, and mechanical properties. This review provides an overview of typical bionic-structured materials in SSEs, particularly those mimicking plant and animal structures, with a focus on their latest advancements in applications of solid-state lithium metal batteries. Commencing from plant structures encompassing roots, trunks, leaves, flowers, fruits, and cellular levels, the detailed influence of biomimetic strategies on SSE design and electrochemical performance are presented in this review. Subsequently, the recent progress of animal-inspired nanostructures in SSEs is summarized, including layered structures, surface morphologies, and interface compatibility in both two-dimensional (2D) and three-dimensional (3D) aspects. Finally, we also evaluate the current challenges and provide a concise outlook on future research directions. We anticipate that the review will provide useful information for future reference regarding the design of bionic-structured materials in SSEs.

The synthesis of gold nanoclusters with high stability and their application in fluorometric detection for Hg2+ and cell imaging.

Sensing Hg2+ is significant to protecting human health and environmental ecosystems, for its toxicity and genotoxicity. Here, highly stable fluorescent folic acid (FA)-protected Au nanoclusters (FA-AuNCs) were synthesized by optimizing the reactive parameters with high quantum yield of 34.7%. Main components of Au4L were confirmed by MALDI-TOF, and the electron-rich residues of FA shell enabled FA-AuNCs excellent photostability. FA-AuNCs exhibited sensitive response behavior to Hg2+ with a minimum detectability of 1.3 nM, and presented extreme effect to the detection of Hg2+ in real water. Notably, the cellular imaging and in-situ detection of Hg2+ in cells can be achieved visually. The high selectivity was attributed to the chemical bond formed between Au+ (4f145d10) and Hg2+ (4f145d10). And the internal filter effect and static quenching effect were proved triggering the quenching of FA-AuNCs. The ultra-stable FA-AuNCs provide a potential promising opportunity for the in-situ tracing Hg2+ from environmental and biological samples.

High crystallinity Sn crystals on Ni foam: an ideal bimetallic catalyst for the electroreduction of carbon dioxide to syngas.

The investigation of highly efficient catalysts for the electrochemical reduction of carbon dioxide (ER-CO2) is the most critical challenge to commercialize conversion and utilization of CO2. Herein we propose a new and very promising catalyst, high crystallinity Sn crystals on Ni foam (Sn@f-Ni), for the electroreduction reaction of CO2 in potassium bicarbonate aqueous solution. The catalyst is fabricated in situ on a pretreated Ni foam substrate through a galvanostatic electrodeposition strategy. SEM and XRD demonstrate that high crystallinity Sn crystals, with an average size of 2-3 µm, evenly dispersed on the Ni foam support can be reproducibly obtained. Electrochemical measurements demonstrate that the Sn@f-Ni electrode at the deposition current of 15 mA exhibits superior performance in promoting the ER-CO2. Tafel measurements show that except for electrodes with a deposition current of 5 mA, the Tafel slopes of the other four electrodes are all above 100 mV dec-1, which is consistent with a rate-determining initial electron transfer to CO2 to form a surface adsorbed intermediate, a mechanism that is commonly invoked for metal electrodes. A stable composition of syngas can be obtained by electrolysis at -1.7 V potential (vs. Ag/AgCl), indicating that the Sn surface with high crystallinity conforms to the Heyrovsky-Volmer mechanism at a potential of -1.7 V. The ratio of CO and H2 generation was about 1 : 2, meaning it could be used as syngas for preparing some valuable fuels. This work provided an efficient method to convert the surplus CO2 to valuable syngas.

A Removable Artificial Cell Wall for Withstanding Ciprofloxacin.

The pollution of antibiotics in aquaculture environment is increasingly serious, and excessive antibiotics will kill the probiotics in aquaculture feed. How to improve the viability of probiotics in the antibiotics-contaminated environment is of significance. In this study, a new strategy for protecting Saccharomyces cerevisiae cells in situ against antibiotics is constructed based on cell surface engineering technology by putting on wearable protective layers for cells. The protective layer is constructed around cellular surface via the self-assembly of coacervate microdroplets that consist of carboxymethyl chitosan and carboxyl dextran. Without affecting the cell viability, the protective layer can grasp ciprofloxacin and decrease the contact of ciprofloxacin to cells and consequently improve the survival rate of cells when exposing to ciprofloxacin. This work highlights a facile strategy to establish removable artificial cell wall by biodegradable polysaccharides for improving the productivity of probiotics in antibiotic environments.

Knockdown of IQGAP1 inhibits proliferation and epithelial-mesenchymal transition by Wnt/ß-catenin pathway in thyroid cancer.

BACKGROUND: Thyroid cancer is the most common endocrine malignant disease with a high incidence rate. The expression of IQGAP1 is upregulated in various cancers, including thyroid cancer. However, the role and underlying mechanism of IQGAP1 in thyroid cancer are still not clear. MATERIALS AND METHODS: The expression of IQGAP1 in thyroid cancer tissues and cells was determined by reverse transcription polymerase chain reaction and Western blot analysis. Cells were transfected with different siRNAs using Lipofectamine 2000 or were treated with various concentrations of XAV939. The effects of IQGAP1 knockdown on proliferation and epithelial-mesenchymal transition (EMT) of thyroid cancer cells were determined by MTT assay and Western blot analysis. Animal experiments were performed to investigate the effects of IQGAP1 knockdown on the growth of tumors in vivo. RESULTS: High IQGAP1 expression is found in thyroid cancer tissues and cells. Knockdown of IQGAP1 had inhibitory effects on cell proliferation and EMT, as well as on the Wnt/ß-catenin pathway. Additionally, inactivation of the Wnt/ß-catenin pathway by XAV939 or si-ß-catenin suppressed cell proliferation and EMT. Furthermore, suppression of the Wnt/ß-catenin pathway reversed the positive effects of pcDNA-IQGAP1 on cell proliferation and EMT in vitro. Moreover, downregulation of IQGAP1 suppressed tumor growth and EMT in SW579 tumor xenografts through the Wnt/ß-catenin pathway in vivo. CONCLUSION: Our study demonstrated that knockdown of IQGAP1 inhibited cell proliferation and EMT through blocking the Wnt/ß-catenin pathway in thyroid cancer.

Silencing of A-Kinase Anchor Protein 4 (AKAP4) Inhibits Proliferation and Progression of Thyroid Cancer.

A-kinase anchor protein 4 (AKAP4), a member of the A-kinase anchor family of proteins, plays a role in tumor development and progression. However, its expression pattern and function in human thyroid cancer remain obscure. Here we examined AKAP4 expression in thyroid cancer cell lines as well as the effects of AKAP4 on the proliferation and metastasis of thyroid cancer cells. We also explored the molecular mechanism by which AKAP4 mediates the metastatic potential of thyroid cancer cells. Our results revealed that the transcript and protein levels of AKAP4 were significantly upregulated in thyroid cancer cell lines. In vitro experiments showed that knockdown of AKAP4 significantly inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) process in thyroid cancer cells. Additionally, knockdown of AKAP4 greatly decreased the protein expression of Shh as well as Smo, Ptc, and Gli-1 in ACT-1 cells. Finally, the in vivo nude mice model confirmed that knockdown of AKAP4 attenuated tumor growth. In conclusion, our findings demonstrated that knockdown of AKAP4 inhibited proliferation and metastasis, likely through suppressing the Shh signaling pathway, in thyroid cancer cells. Thus, AKAP4 may act as a potential therapeutic target for human thyroid cancer.

Construction of biological hybrid microcapsules with defined permeability towards programmed release of biomacromolecules.

An effective method to modulate the permeability of microcapsules on demand based on a "self-sacrificing" strategy was demonstrated, which then realized a programmed release of the corresponding loaded biomacromolecules.

Bio-inspired engineering proteinosomes with a cell-wall-like protective shell by self-assembly of a metal-chelated complex.

A cell-wall-like shell is constructed around proteinosomes by coordination complexes of tannic acid and Fe3+, which endows the engineered proteinosomes with an enhanced Young's modulus of the membrane, protease resistant ability, EDTA-mediated release of loaded DNA, and electrostatic gated encapsulated enzyme activity, as well as antioxidant capacity.

Establishment of pancreatic cancer stem cells by flow cytometry and their biological characteristics.

To investigate the method of separating human pancreatic cancer stem cells by Hoechst 33342 labeled flow cytometry and to analyze the biological properties of pancreatic cancer stem cells. The human pancreatic cancer cell line PC-3 was divided into SP and non-SP cells by flow cytometry. The number of two cell clone spheres and nude mice tumor formation rates were compared by cultivating in serum-free medium; The expression of CD133, Nestin mRNA and protein was analyzed by real-time fluorescence quantitative PCR and Western blot; The expression of two cell drug resistance genes (MDR1, ABCG2, ABCA2 and MRP1) was analyzed by real time fluorescent quantitative PCR. The number of the cloned spheres in SP cells in serum-free medium was significantly higher than that of non-SP cells (P<0.05). The incidence of SP cells in the tumor of immunodeficiency nude mice was significantly higher than that of non-SP cells, and the difference was statistically significant (P<0.05). Real-time fluorescence quantitative PCR analysis showed that the expression of CD133 and Nestin mRNA in SP cells was significantly higher than those of non-SP cells, and the expression of CD133 and Nestin protein in SP cells was also significantly higher than those of non-SP cells (P<0.05). In conclusion, SP side population pancreatic cancer cells by Hoechst 33342 separation have the stem cell characteristics, higher tumor formation rate and higher drug resistance, which may be related to chemotherapy resistance.

MiR-200 Regulates Epithelial-Mesenchymal Transition in Anaplastic Thyroid Cancer via EGF/EGFR Signaling.

This study was set to study the molecular mechanism underlying how miR-200 regulates EGF/EGFR signaling to involve in epithelial-mesenchymal transition (EMT) in anaplastic thyroid cancer (ATC) cells. Loss-of-function experiments of EGFR silencing by siRNA transfection was performed. Transfection of pre-miR-200s or anti-miR-200s was used to increase or decrease miR-200 transcripts. Real-time PCR, Western blot, immunohistochemistry, and transwell experiments were performed to determine the role of miR-200s in EMT and its role in EGF/EGFR-mediated EMT in vitro and in vivo. EGF/EGFR signaling activation increased the expression of mesenchymal marker vimentin in Nthy-ori 3-1 cells and decreased the expression of endothelial maker E-cadherin. EGF stimulation led to increased RhoA expression in Nthy-ori 3-1 cells. EGFR silencing resulted in decreased RhoA expression in SW1736 and ARO cells. EGF stimulation led to down-regulation of miR-200s and EMT. Restoration of miR-200 expression by pre-miR-200a/c transfection reversed the process, including increased E-cadherin and decreased vimentin. Down-regulation of miR-200 by anti-miR-200 effectively reduced miR-200. Matrigel invasion assay proved that restoration of miR-200 expression counteracted invasiveness. EGFR silencing decreased invasiveness in SW1736 cells, while down-regulation of miR-200s restored invasiveness. Xenograft tumors of SW1736 cells with cotransfection of anti-miR-200s and EGFR siRNA which kept the similar E-cadherin and vimentin expression with the untransfected controls. In ATC cells, miR-200s play a central role in EGF/EGFR-mediated invasiveness in vitro and EMT in vivo.

Fluorescent detection of TNT and 4-nitrophenol by BSA Au nanoclusters.

Rapid and sensitive detection of 2,4,6-trinitrotoluene (TNT) and 4-nitrophenol (4-NP) has attracted considerable attention due to their wide applications as nitroaromatic explosive materials. A novel fluorescence method for TNT and 4-NP based on bovine serum albumin functionalized fluorescent gold nanoclusters (BSA Au-NCs) has been developed. The detection probe BSA Au-NCs can be used as a fluorescent probe for the sensitive and selective detection of TNT and 4-NP simultaneously. A good linearity of fluorescence detection using BSA Au-NCs as a fluorescent probe was observed for TNT and 4-NP concentrations in the range of 10(-8)-5 × 10(-5) M and 10(-9)-5 × 10(-5) M, with a detection limit of 10 nM and 1 nM, respectively. The high specificity of TNT and 4-NP with BSA Au-NCs interactions provided excellent selectivity towards detecting TNT and 4-NP over other relevant nitroaromatic compounds. This system can be applied to test strips to detect TNT and 4-NP with high sensitivity and selectivity. The vapour of TNT and 4-NP can be detected using BSA Au-NCs test paper within 1 min with a detection limit of 10 pM and 1 pM.