Density functional theory calculations have been performed to investigate the binding and diffusion behavior of Li in phosphorene. Our studies reveal the following findings: (1) Li atom forms strong ...binding with phosphorus atoms and exists in the cationic state; (2) the shallow energy barrier (0.08 eV) of Li diffusion on monolayer phosphorene along zigzag direction leads to an ultrahigh diffusivity, which is estimated to be 102 (104) times faster than that on MoS2 (graphene) at room temperature; (3) the large energy barrier (0.68 eV) along armchair direction results in a nearly forbidden diffusion, and such strong diffusion anisotropy is absent in graphene and MoS2; (4) a remarkably large average voltage of 2.9 V is predicted in the phosphorene-based Li-ion battery; and (5) a semiconducting to metallic transition induced by Li intercalation of phosphorene gives rise to a good electrical conductivity, ideal for use as an electrode. Given these advantages, it is expected that phosphorene will present abundant opportunities for applications in novel electronic device and lithium-ion battery with a high rate capability and high charging voltage.
An NIR‐responsive mesoporous silica coated upconverting nanoparticle (UCNP) conjugate is developed for controllable drug delivery and fluorescence imaging in living cells. In this work, antitumor ...drug doxorubicin (Dox) molecules are encapsulated within cross‐linked photocaged mesoporous silica coated UCNPs. Upon 980 nm light irradiation, Dox could be selectively released through the photocleavage of theo‐nitrobenzyl (NB) caged linker by the converted UV emission from UCNPs. This NIR light‐responsive nanoparticle conjugate demonstrates high efficiency for the controlled release of the drug in cancer cells. Upon functionalization of the nanocarrier with folic acid (FA), this photocaged FA‐conjugated silica‐UCNP nanocarrier will also allow targeted intracellular drug delivery and selective fluorescence imaging towards the cell lines with high level expression of folate receptor (FR).
A NIR‐controllable drug nanocarrier based on silica‐coated upconverting nanoparticles is presented. Upon functionalization of the photoactive nanocarrier with folic acid, selective cell imaging and targeted drug delivery can be easily achieved in tumor cells with overexpression of folate receptor.
The most notable role of small interfering RNA (siRNA) is in RNA interference (RNAi) and post-transcriptional gene silencing, which leads to a surge of interest in RNAi for both biomedical research ...and therapeutic applications. However, "naked" siRNA cannot cross cellular membranes freely because of highly negative charges which limits its utility for gene therapy. In this work, a system of near-infrared (NIR) light-induced siRNA release from silica coated upconversion nanoparticles (Si-UCNPs) is presented. These Si-UCNPs were functionalized with cationic photocaged linkers through covalent bonding, which could effectively adsorb anionic siRNA through electrostatic attractions and were easily internalized by living cells. Upon NIR light irradiation, the photocaged linker on the Si-UCNPs surface could be cleaved by the upconverted UV light and thus initiated the intracellular release of the siRNA. The in vitro agarose gel electrophoresis and intracellular imaging results indicated that the Si-UCNPs-based gene carrier system allowed effective siRNA delivery and the applications of NIR light instead of direct high energy UV irradiation may greatly guarantee less cell damage.
The deteriorating state of global fresh water resources represents one of the most serious challenges that scientists and policymakers currently face. Desalination technologies, which are designed to ...extract potable water from the planet’s bountiful stores of seawater, could serve to alleviate much of the stress that presently plagues fresh water supplies. In recent decades, desalination methods have improved via water-filtering architectures based on nanoporous graphene filters and artificial membranes integrated with biological water channels. Here, we report the auspicious performance (in simulations) of an alternative nanoporous desalination filter constructed from a MoS2 nanosheet. In striking contrast to graphene-based filters, we find that the “open” and “closed” states of the MoS2 filter can be regulated by the introduction of mechanical strain, yielding a highly tunable nanopore interface. By applying lateral strain to the MoS2 filter in our simulations, we see that the transition point between “open” and “closed” states occurs under tension that induces about 6% cross-sectional expansion in the membrane (6% strain); the open state of the MoS2 filter demonstrates high water transparency and a strong salt filtering capability even under 12% strain. Our results thus demonstrate the promise of a controllable nanoporous MoS2 desalination filter, wherein the morphology and size of the central nanopore can be precisely regulated by tensile strain. These findings support the design and proliferation of tunable nanodevices for filtration and other applications.
Biofilm infections can induce chronic inflammation and stall the normal orchestrated course of wound-healing cascades. Herein, pH-switchable antimicrobial hydrogel with nanofiber networks for biofilm ...eradication and rescuing stalled healing in chronic wounds is reported on the basis of the self-assembly of a designed octapeptide (IKFQFHFD) at neutral pH. This hydrogel is biocompatible and exhibits an acidic pH (pathological environment of infected chronic wounds)-switchable broad-spectrum antimicrobial effect via a mechanism involving cell wall and membrane disruption. The antimicrobial activity of hydrogel is derived from its acidic pH-dependent nanofiber network destabilization and activated release of IKFQFHFD, which is antimicrobial only at acidic pH due to the antimicrobial peptide-like molecular structure. In addition, supramolecular nanofiber networks loaded with drugs of cypate (photothermal agent) and proline (procollagen component) are further developed. In vitro experiments show that loaded drugs exhibit acidic pH (pH ∼ 5.5)-responsive release profiles, and synergistic biofilm eradication and subsequent healing cascade activation of cells proliferation are achieved on the basis of the supramolecular nanofiber networks. Remarkably, the nanofiber networks of hydrogel enable in vivo complete healing of MRSA biofilm infected wound in diabetic mice within 20 days, showing great potential as promising chronic wound dressings. The proposed synergistic strategy for eradicating biofilm and activating subsequent healing cascades may offer a powerful modality for the management of clinical chronic wounds.
It is widely accepted that the oxygen level in tumor tissue is significantly lower than the adjacent normal tissue, thus termed hypoxia. Intratumoral hypoxia represents a major driving force in ...cancer progression, recurrence, metastasis, and decreased survival. Though multiple gene signatures reflect the complex cellular response to hypoxia have been established in several cancer types such as head and neck, breast, and lung cancers, the hypoxic panorama in colorectal cancer (CRC) remains poorly understood.
A hypoxic signature constituted by a total of 356 genes, including canonical hypoxia-responsive ADM, ANGPTL4, CA9, and VEGFA, was established based on systemic literature search. A total of 1,730 CRC samples across four independent cohorts were used for
Prognosis, molecular signatures, pathways, and tumor-infiltrating lymphocytes were compared between the subtypes.
CRCs mainly fell into two subgroups, one indicated as hypoxia and the other one designated as normoxia. Hypoxia was correlated with poor outcomes in CRC and will increase the risk of a subset of stage II patients to the level of normoxic stage III. Additionally, hypoxia was closely associated with activation of RAS signaling pathway independent of
mutation. More M2 macrophage infiltration was another hypoxic marker indicated that subsets of patients with high M2 macrophages may benefit from macrophage-targeting therapy.
These findings will facilitate the development of a hypoxia-oriented therapy strategy to enhance the treatment effect in the near future.
Effective CO2 capture and activation is a prerequisite step for highly efficient CO2 reduction. In this study, we reported a case of Cu2+ in a porphyrin based MOF promoted enhanced photocatalytic CO2 ...conversion to methanol. Compared with the sample without Cu2+, the methanol evolution rate was improved as high as 7 times. In situ FT-IR results suggested that CO2 chemical adsorption and activation over Cu2+ played an important role in improving the conversion efficiency.
Although multifunctional upconversion imaging probes have recently attracted considerable interest in biomedical research, there are currently few methods for stabilizing these luminescent nanoprobes ...with oligonucleotides in biological systems. Herein, a method to robustly disperse upconversion nanoprobes in physiological buffers based on rational design and synthesis of nanoconjugates comprising hairpin‐DNA‐modified gold nanoparticles is presented. This approach imparts the upconversion nanoprobes with excellent biocompatibility and circumvents the problem of particle agglomeration. By combining single‐band anti‐Stokes near‐infrared emission and the photothermal effect mediated by the coupling of gold to upconversion nanoparticles, a simple, versatile nanoparticulate system for simultaneous deep‐tissue imaging and drug molecule release in vivo is demonstrated.
Current strategies for surface functionalization often yield the resulting upconversion nanoparticles with limited biocompatibility, specificity, functionality, and dispersibility in high‐salt physiological environment. To this end, a rational design and synthesis of hairpin DNA‐functionalized upconversion/gold nanoprobes is presented featuring improved stability, which is particularly useful for deep‐tissue drug delivery.
Trading up: A bioimaging system that is based on caged D‐luciferin/upconversion nanoparticle conjugate has been developed. The nanoparticles upconvert near‐infrared light into UV light, which ...triggers the photorelease of D‐luciferin (see scheme) and leads to enhanced fluorescence and bioluminescence signals in vitro and in vivo. The use of near‐infrared light enables deep penetration into tissue in vivo with minimum cellular damage.
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•Effects of extraction condition on AAEM determination in were experimentally studied.•An improved sequential extraction method was proposed with clearly defined conditions.•The new ...method has higher accuracy and is less time consuming.•AAEM occurrence modes and contents in three Zhundong coals were determined by the new method.•Mineral patterns in raw coal and extraction residues were analyzed by XRD.
Zhundong coal is one of the most important coals in China due to its huge reserve, but it causes severe fouling and slagging problems when it is burnt in boilers for its high AAEMs (alkali and alkaline earth metal species) contents. Accurately determination of the occurrence modes and contents of AAEMs in Zhundong coals is a necessary step to overcome the ash-related problems. Nowadays, different researchers used different methods or procedures to determine AAEMs in Zhundong coals, and the data were scattering. Based on a series of experiments on the effects of extraction conditions, an improved extraction method with clearly defined conditions for each extraction step was proposed. 0.1mol/L NH4Cl (pH=8.5) instead of 1mol/L NH4OAc (pH=7) was used to extract the exchangeable AAEMs in Zhundong coals to avoid the high solubility of carbonates in the extraction solution. The improved method was more accurate and took much less time than the conventional one. With the proposed extraction method, the occurrence modes and contents of AAEMs in three Zhundong coals were measured. The results revealed that Na is mainly water soluble (Naw/Natotal=50–85%) which is halite or in the form of surface bound Na+, while Ca and Mg are mainly acid soluble (Caac/Catotal=60–90%, Mgac/Mgtotal=45–90%) which are carbonates together with a little amount of sulfates. Exchangeable AAEMs organically bonded to the coal matrix are not the main occurrence mode of AAEMs. Acid insoluble Ca-species could be rankinite. The amounts of AAEMs in the same occurrence mode could be remarkably different among coals from different Zhundong district. The improved sequential extraction method can be extended to determine AAEMs in high carbonate-containing coals.
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