Long-term plant diversity increases soil extractable organic carbon and nitrogen contents in a subtropical forest.

Plant diversity is one of the various factors influencing ecosystem functions such as soil carbon (C) and nitrogen (N) stocks. Soil extractable organic carbon (EOC) and nitrogen (EON) contents are active fractions in soil organic matter, but little is known about the impact of variations in long-term plant diversity on soil EOC and EON contents in forest ecosystems. Utilizing the Biodiversity-Ecosystem Functioning Experiment China platform, we selected long-term plant diversity level treatments, distinguished the functional types of evergreen and deciduous plants, and explored their effects on soil EOC and EON contents. The results showed that soil EOC and EON contents increased significantly with greater plant diversity, which is mainly attributed to proportional increases in complementary effects. After distinguishing plant functional types, we did not find the strong complementary effects at the mixed planting of evergreen and deciduous tree species. Within two-species planting mixtures, evergreen tree species can increase soil EON compared to deciduous tree species. Cyclobalanopsis have a strong carbon and nitrogen storage capacity, suggesting that increasing the plant diversity and the proportion of Cyclobalanopsis planting in forest management will promote carbon and nitrogen accumulation in forest soil. These findings enhance our understanding of long-term forest C and N cycling processes and also provide theoretical support for managing forest soil C sinks.

Morpholine-modified permethyl ß-cyclodextrin supramolecular nanoparticles for precise dual-targeted imaging.

Possessing dual-targeted agents toward the lysosome and cancer cells, a ternary supramolecular assembly was constructed by a morpholine-modified permethyl ß-cyclodextrin, sulfonated porphyrin, and folic acid-modified chitosan via multivalent interactions. As compared with free porphyrin, the obtained ternary supramolecular assembly showed promoted photodynamic effect and achieved dual-targeted precise imaging in cancer cells.

Nanoreactor Based on Cyclodextrin for Direct Electrocatalyzed Ammonia Synthesis.

The high-efficiency transition metal-free electrocatalytic nitrate reduction reaction (NO3-RR) for ammonia synthesis has received more attention because of its green and environmentally friendly characteristics. Here, we report an efficient electrochemical NH3 synthesis directly from purely organic macrocyclic compounds α-, ß-, and γ-cyclodextrins (CDs)-catalyzed transition metal-free electroreduction of nitrate under ambient conditions. In comparison with α-, and ß-CDs, parent γ-CD presented uncommon catalytic performance with a relatively higher NH3 yield that can reach up to 2.28 mg h-1 cm-2 with a Faradaic efficiency (FE) of 63.2% at -0.9 V versus a reversible hydrogen electrode in alkaline medium, and the potassium ion-coordinated γ-CD complex can achieve a maximum NH3 production rate up to 4.66 mg h-1 cm-2 with an NH3 FE of 79.3%. Further comparison with permethyl-γ-CD, d-glucose, and poly(vinyl alcohol) for the NO3-RR indicated that the typical torus-shaped cyclic conformation and edge hydroxyl groups of parent CDs play important roles in the electrocatalytic process. The K+-mediated 3D γ-CD-K+ frameworks containing six CDs as nanoreactors greatly strengthen the enrichment effect of nitrate through hydrogen-bonding interaction and electrostatic interaction and promote the mass transfer, thus leading to the efficient NO3-RR in an alkaline electrolyte. This work provides a convenient, green, and economic method for high-performance NO3-RR, which has potential applications in the fields of environment, energy, and industry.

Supramolecular Assembly of ß-Cyclodextrin-Modified Polymer by Electrospinning with Sustained Antibacterial Activity.

Supramolecular assembly loading drug as biomedical materials is a research hotspot. Herein, we reported a supramolecular electrospun assembly constructed via the hydrophobic and hydrogen bonding interaction. The obtained results showed that the assembly by supramolecular electrospinning not only increased the interactions of multiple antibacterial active species including antibiotics, cationic polymers, and silver to form a flexible membrane with good mechanical strength but also indicated the dual effects of rapid doxycycline and polyethyleneimine release as well as a sustained Ag release. Interestingly, the assembly showed not only good degradability but also a high bacteriostatic efficacy toward Escherichia coli (E. coli) up to 99.9%. More importantly, the in vivo wound healing assay indicated that the assembly could promote the healing of uninfected, E. coli-infected, and even methicillin-resistant staphylococcus aureus-infected wounds. The current research provides a novel approach to construct a supramolecular assembly by electrospinning mechanically induced strong noncovalent interaction.

Directional Water Transfer Janus Nanofibrous Porous Membranes for Particulate Matter Filtration and Volatile Organic Compound Adsorption.

In order to reduce the possible harm caused by air pollution, excellent personal protective materials are attracting more and more attention. Therefore, the research of multifunctional materials that can filter particulate matter (PM) and volatile organic compounds (VOCs) simultaneously is of great significance. In addition, in cold weather, water vapor in the exhaled gas condenses into small droplets inside the respirator causing uncomfortable feeling of dampness. Herein, we prepared several types of cyclodextrin-containing Janus nanofibrous porous membranes by electrospinning, which can efficiently filter PM of different sizes in the air, effectively adsorb VOCs, and orientate moisture from exhaled gas to the outside of the membranes to provide a dry and comfortable environment. These advantageous features, combined with the cheap price and easy availability of component materials and low respiratory resistance, highlight the great potential of these Janus nanofibrous porous membranes in the development of personal wearable air purifiers.

A Synergistic Enhancement Strategy for Realizing Ultralong and Efficient Room-Temperature Phosphorescence.

An enhancement strategy is realized for ultralong bright room-temperature phosphorescence (RTP), involving polymerization between phosphor monomers and acrylamide and host-guest complexation interaction between phosphors and cucurbit[6,7,8]urils (CB[6,7,8]). The non-phosphorescent monomers exhibit 2.46 s ultralong lifetime after copolymerizing with acrylamide. The improvement is due to the rich hydrogen bond and carbonyl within the polymers which promote intersystem crossing, suppress nonradiative relaxation and shield quenchers effectively. By tuning the ratio of chromophores, a series of phosphorescent copolymers with different lifetimes and quantum yields are prepared. The complexation of macrocyclic hosts CB[6,7,8] promote the RTP of polymers by blocking aggregation-caused quenching, and offsetting the losses of aforementioned interaction provided by polymer. Multiple lifetime-encoding for digit and character encryption are achieved by utilizing the difference of their lifetimes.

MOF-based fibrous membranes adsorb PM efficiently and capture toxic gases selectively.

Air pollution is harmful to the functioning of the lungs, heart, and brain even at low concentrations of particle matter (PM) and toxic gases. Purification methods and materials have made tremendous progress to improve the purity of air to adhere to national quality standards. Metal-organic frameworks (MOFs) have an excellent gas adsorption capacity due to their high specific surface area and porous structure, but the intrinsic fragility of MOF crystals limits their application. In this study, we selected appropriate organic ligands to prepare MOF-surface-grown fibrous membranes using an electrospinning technique, which have an excellent ability to adsorb PM and capture toxic gases selectively. The efficiency of the MOF-surface-grown fibrous membranes to remove PM reached 99.99%, even for fine PM. More importantly, under low partial pressure and complex gas composition conditions, the fibrous membrane was able to selectively adsorb SO2. The concentration of SO2 dropped from 7300 ppb to 40 ppb. Interestingly, the MOF-surface-grown fibrous membrane had a higher purification capacity toward O3 than toward SO2. The concentration of O3 rapidly dropped from 3000 ppb to 7 ppb, which was far below national air quality standards (81 ppb). The MOF-surface-grown fibrous membrane was able to adsorb toxic atmospheric gases selectively, while not being influenced by the presence of other gases, such as CO2 and O2. MOF-based fibrous membranes prepared using a simple and inexpensive electrospinning technique have wide potential for practical use in the field of environmental protection and air purification.

Poly(lactic-co-glycolic acid)/Polycaprolactone Nanofibrous Membranes for High-Efficient Capture of Nano- and Microsized Particulate Matter.

The incidence of many diseases is closely related to air pollution. Suspended particulate matter of different sizes represents a major source of environmental pollution. Fine particles, especially ultrafine particles smaller than 2.5 µm, might be more harmful to human health because of their extremely small size, which enables them to penetrate human lungs and bronchi and makes them difficult to filter out. Therefore, the fatal risks associated with PM call for the development of air purification materials with high efficiency and low resistance. In this study, poly(lactic-co-glycolic acid) and polycaprolactone were used to prepare nanofibrous membranes suitable for the efficient capture of particulate matter formed in haze-fog episodes, especially particles smaller than 0.5 µm. The present nanofibrous membranes exhibit superior filtration efficiency for particulate matter, with a much lower pressure drop compared to typical commercial microfiber air filters. Thanks to the combination of small pore size, high porosity, and robust mechanical properties, the poly(lactic-co-glycolic acid)/polycaprolactone (6:4) composite membrane exhibits a high filtration efficiency of 97.81% and a low pressure drop of 181 Pa. These favorable features, combined with the easy availability and biocompatibility of the component materials, highlight the promising potential of the present nanofibrous membranes for the development of personal wearable air purifiers.

Direct site-specific treatment of skin cancer using doxorubicin-loaded nanofibrous membranes.

Doxorubicin (DOX) is widely used in cancer therapy. However, its application is sometimes limited by its adverse cardiotoxicity and delivery pathways. In our study, we prepared a topical implantable delivery device for controlled drug release and site-specific treatment. The core region consisted of poly (lactic co-glycolic acid) and poly-caprolactone, whereas the shell region was composed of cross-linked gelatin. DOX was enclosed in the core region of a core-shell nanofiber obtained by electrospinning. This implantable delivery device was implanted on the top of the melanoma in a mouse model, which had shown a DOX-controlled release profile with sustained and sufficient local concentration against melanoma growth in mice with negligible side effects. Compared with the traditional intravenous administration, the implantable device allows precisely localized treatment and therefore can reduce the dose, decrease the injection frequency, and ensure antitumor efficacy associated with lower side effects to normal tissues. Using a coaxial electrospinning process, it is promising to deliver different hydrophobic or hydrophilic drugs for direct tumor site-specific therapy without large systemic doses and minimized systemic toxicity.

Innovative biodegradable poly(L-lactide)/collagen/hydroxyapatite composite fibrous scaffolds promote osteoblastic proliferation and differentiation.

The development of an artificial bone graft which can promote the regeneration of fractures or diseased bones is currently the most challenging aspect in bone tissue engineering. To achieve the purpose of promoting bone proliferation and differentiation, the artificial graft needs have a similar structure and composition of extracellular matrix. One-step electrospinning method of biocomposite nanofibers containing hydroxyapatite (HA) nanoparticles and collagen (Coll) were developed for potential application in bone tissue engineering. Nanocomposite scaffolds of poly(L-lactide) (PLLA), PLLA/HA, PLLA/Coll, and PLLA/Coll/HA were fabricated by electrospinning. The morphology, diameter, elements, hydrophilicity, and biodegradability of the composite scaffolds have been investigated. The biocompatibility of different nanocomposite scaffolds was assessed using mouse osteoblasts MC3T3-E1 in vitro, and the proliferation, differentiation, and mineralization of cells on different nanofibrous scaffolds were investigated. The results showed that PLLA/Coll/HA nanofiber scaffolds enhanced cell adhesion, spreading, proliferation, differentiation, mineralization, and gene expression of osteogenic markers compared to other scaffolds. In addition, the nanofibrous scaffolds maintained a stable composition at the beginning of the degradation period and morphology wastage and weight loss were observed when incubated for up to 80 days in physiological simulated conditions. The PLLA/Coll/HA composite nanofibrous scaffolds could be a potential material for guided bone regeneration.