In the past decade, mesoporous silica nanoparticles (MSNs) have attracted more and more attention for their potential biomedical applications. With their tailored mesoporous structure and high ...surface area, MSNs as drug delivery systems (DDSs) show significant advantages over traditional drug nanocarriers. In this review, we overview the recent progress in the synthesis of MSNs for drug delivery applications. First, we provide an overview of synthesis strategies for fabricating ordered MSNs and hollow/rattle‐type MSNs. Then, the in vitro and in vivo biocompatibility and biotranslocation of MSNs are discussed in relation to their chemophysical properties including particle size, surface properties, shape, and structure. The review also highlights the significant achievements in drug delivery using mesoporous silica nanoparticles and their multifunctional counterparts as drug carriers. In particular, the biological barriers for nano‐based targeted cancer therapy and MSN‐based targeting strategies are discussed. We conclude with our personal perspectives on the directions in which future work in this field might be focused.
Mesoporous silica nanoparticles (MSNs) are drawing growing attention for their biomedical applications. With unique mesoporous structure, high surface area and low toxicity, MSNs exhibit super performance as versatile drug delivery systems especially for cancer therapy. This review focuses on recent progresses of synthesis strategies, biocompatibility research and drug delivery application of MSNs.
Owing to their self‐renewal and differentiation ability, stem cells are conducive for repairing injured tissues, making them a promising source of seed cells for tissue engineering. The extracellular ...microenvironment (ECM) is under dynamic mechanical control, which is closely related to stem cell behaviors. During the design and fabrication of biomaterials for regenerative medicine, the physiochemical properties of the natural ECM should be closely mimicked, which can reinforce stem cell lineage choice and tissue engineering. By reproducing the biophysical stimulations that stem cells may experience in vivo, many studies have highlighted the key role of biophysical cues in regulation of cell fate. Optimization of biophysical factors leads to desirable stem cell functions, which can maximize the effectiveness of regenerative treatment. In this review, the main biophysical cues of biomaterials, including stiffness, topography, mechanical force, and external physical fields are summarized, and their individual and synergistic influence on stem cell behavior is discussed. Subsequently, the current progress in tissue regeneration using biomaterials is presented, which directs the design and fabrication of functional biomaterial. The mechanisms via which biophysical cues activate cellular responses are also analyzed. Finally, the challenges in basic research as well as for clinical translation in this field are discussed.
Biophysical cues of biomaterials can simulate the characteristics of natural extracellular matrix to manipulate the fate of stem cells. This review discusses the biophysical cues integrated by functional biomaterials and the cellular response at the cell–biomaterial interface via mechanotransduction. The related application in bone, nerve, and cardiac tissue engineering is also summarized.
Abstract
Rational regulation of electrochemical reconfiguration and exploration of activity origin are important foundations for realizing the optimization of electrocatalyst activity, but rather ...challenging. Herein, we potentially develop a rapid complete reconfiguration strategy for the heterostructures of CoC
2
O
4
coated by MXene nanosheets (CoC
2
O
4
@MXene) during the hydrogen evolution reaction (HER) process. The self-assembled CoC
2
O
4
@MXene nanotubular structure has high electronic accessibility and abundant electrolyte diffusion channels, which favor the rapid complete reconfiguration. Such rapid reconfiguration creates new actual catalytic active species of Co(OH)
2
transformed from CoC
2
O
4
, which is coupled with MXene to facilitate charge transfer and decrease the free energy of the Volmer step toward fast HER kinetics. The reconfigured components require low overpotentials of 28 and 216 mV at 10 and 1000 mA cm
−2
in alkaline conditions and decent activity and stability in natural seawater. This work gives new insights for understanding the actual active species formation during HER and opens up a new way toward high-performance electrocatalysts.
Metal single‐atom materials with their high atom utilization efficiency and unique electronic structures usually show remarkable catalytic performances in many crucial chemical reactions. Herein, a ...facile and easily scalable “impregnation‐carbonization‐acidification” strategy for fabricating a class of single‐atom‐anchored (including cobalt and nickel single atoms) monolith as superior binder‐free electrocatalysts for developing high‐performance wearable Zn–air batteries is reported. The as‐prepared single atoms, supported by N‐doped carbon flake arrays grown on carbon nanofibers assembly (M SA@NCF/CNF), demonstrate the dual characteristics of excellent catalytic activity (reversible oxygen overpotential of 0.75 V) and high stability, owing to the greatly improved active sites' accessibility and optimized single‐sites/pore‐structures correlations. Furthermore, wearable Zn–air battery based on Co SA@NCF/CNF air electrode displays superior stability under deformation, satisfactory energy storage capacity, and good practicality to be utilized as an integrated battery system. Theoretical calculations reveal a mechanism for the promotion of the catalytic performances on single atomic sites by lowering the overall oxygen reduction/evolution reaction barriers comparing to metal cluster co‐existing configuration. These findings provide a facile strategy for constructing free‐standing single‐atom materials as well as the engineering of high‐performance binder‐free catalytic electrodes.
A class of single‐atom‐anchored hierarchically porous monoliths for flexible energy storage is prepared by a facile and easily scalable “impregnation–carbonization–acidification” strategy. It exhibits excellent bifunctional electrocatalytic activity for oxygen reduction/evolution reactions. Wearable zinc–air batteries based on this binder‐free monolith show low overpotential and high mechanical stability.
Tissue regeneration, energy conversion & storage, and water treatment are some of the most critical challenges facing humanity in the 21st century. In order to address such challenges, ...one-dimensional (1D) materials are projected to play a key role in developing emerging solutions for the increasingly complex problems. Eletrospinning technology has been demonstrated to be a simple, versatile, and cost-effective method in fabricating a rich variety of materials with 1D nanostructures. These include polymers, composites, and inorganic materials with unique chemical and physical properties. In this tutorial review, we first give a brief introduction to electrospun materials with a special emphasis on the design, fabrication, and modification of 1D functional materials. Adopting the perspective of chemists and materials scientists, we then focus on the recent significant progress made in the domains of tissue regeneration (e.g., skin, nerve, heart and bone) and conversion & storage of clean energy (e.g., solar cells, fuel cells, batteries, and supercapacitors), where nanofibres have been used as active nanomaterials. Furthermore, this review's scope also includes the advances in the use of electrospun materials for the removal of heavy metal ions, organic pollutants, gas and bacteria in water treatment applications. Finally a conclusion and perspective is provided, in which we discuss the remaining challenges for 1D electrospun nanomaterials in tissue regeneration, energy conversion & storage, and water treatment.
We show that interstitial nitrogen doping improves the tensile properties of a CoCrNi alloy. A material with 0.5 at% interstitial nitrogen was compared to a nitrogen-free CoCrNi alloy. The ...nitrogen-doped variant has a stable, single-phase face-centered cubic (FCC) lattice structure without nitrides, also after different annealing treatments (800–900 °C, 10 and 30 min). The nitrogen caused an increase in yield strength by 24–33% at identical ductility compared to the nitrogen-free material with similar grain size. The strengthening effect of nitrogen was explained in terms of the simultaneous increase of the lattice friction stress and of the Hall-Petch coefficient.
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The feasibility of low-field nuclear magnetic resonance (LF-NMR) was investigated to predict the dielectric properties of Chinese yam slices. Changes in relaxation behaviors and dielectric properties ...(at 915 and 2450 MHz) of samples during microwave vacuum drying as well as their relationship were studied. Results showed that the total moisture content decreases gradually over drying time, and the free water was removed first, followed by the immobile water and bound water. Correspondingly, the dielectric constant (ε′) gradually decreased till to reach a relative and stable low value; while the loss factor (ε″) changed slightly first, then decreased gradually and also reached a low value finally. Univariate linear models showed that the signal intensity of free water peak (A23) and the transverse relaxation time of immobile water (T22) had good correlation with dielectric properties. Furthermore, partial least squares regression (PLSR) models with four NMR parameters as variables gave better results with R2P of 0.946, 0.936, 0.962 and 0.921 for ε′ and ε″ at 915 MHz and ε′ and ε″ at 2450 MHz, respectively. The overall results revealed that LF-NMR is suitable for predicting the dielectric properties as a rapid and noninvasive method.
•Drying caused significant changes in the T2 curves.•Moisture-dependent dielectric properties (DPs) were analyzed.•PCA analysis indicated the relation between NMR parameters and DPs.•PLSR model with 4 NMR parameters showed better prediction accuracy for DPs.
•A stochastic frontier analysis (SFA) is used to evaluate urban land use efficiency (ULUE).•The spatial and temporal characteristics of ULUE are analyzed.•Undesirable outputs cause a loss of ...ULUE.•The improvement potential of ULUE is revealed.•Targeted policy suggestions for ULUE improvement are further proposed.
With economic growth facing increasing constraints of resource and environment, intensive land use becomes one of the effective ways to promote urban sustainable development. This paper aims to reveal the spatial and temporal differences in urban land use efficiency (ULUE) in provincial China, and examine the impact of undesirable output (e.g., industrial pollutant emissions) on ULUE using a one-stage stochastic frontier analysis (SFA). Furthermore, we analyze the improvement potential of ULUE. Results show that 1) ULUE in China is relatively low, and it shows a trend of slow growth at an annual growth rate of 0.34 %. 2) Undesirable output causes a loss of ULUE. The loss ratio in the western region is the highest (9.61 %), followed by the central region (8.41 %) and the eastern region (3.93 %). Estimation results of the technical inefficiency function also show that pollution intensity has a negative effect on ULUE. 3) ULUE varies significantly across the country. The mean efficiency values in the eastern, central, and western regions are 0.733, 0.535, and 0.507, respectively. ULUE levels in different provinces present a greater gap when undesirable output is considered. 4) The improvement potential analysis indicates a mismatch between the ULUE and the improvement potential. Areas with low efficiency does not necessarily have relatively high improvement potential (e.g., Ningxia and Xinjiang), or areas with relatively high efficiency may also have high improvement potential (e.g., Fujian and Shandong). Based on the difference in ULUE level and its improvement potential, targeted policy suggestions for ULUE improvement are further proposed.
This reviewer paper summarizes recent progresses in nanozymes for disease therapy through regulation of reactive oxygen species.
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With high catalytic activity and stability, nanozymes ...have huge advantage in generating or eliminating the reactive oxygen species (ROS) due to their intrinsic enzyme-mimicking abilities, therefore attracting wide attention in ROS-related disease therapy. To better design nanozyme-based platforms for ROS-related biological application, we firstly illustrate the catalytic mechanism of different activities, and then introduce different strategies for using nanozymes to augment or reduce ROS level for the applications in cancer therapy, pathogen infection, neurodegeneration, etc. Finally, the challenges and future opportunities are proposed for the development and application of nanozymes.
Rechargeable aluminum‐ion batteries (AIBs) are considered as a new generation of large‐scale energy‐storage devices due to their attractive features of abundant aluminum source, high specific ...capacity, and high energy density. However, AIBs suffer from a lack of suitable cathode materials with desirable capacity and long‐term stability, which severely restricts the practical application of AIBs. Herein, a binder‐free and self‐standing cobalt sulfide encapsulated in carbon nanotubes is reported as a novel cathode material for AIBs. The resultant new electrode material exhibits not only high discharge capacity (315 mA h g−1 at 100 mA g−1) and enhanced rate performance (154 mA h g−1 at 1 A g−1), but also extraordinary cycling stability (maintains 87 mA h g−1 after 6000 cycles at 1 A g−1). The free‐standing feature of the electrode also effectively suppresses the side reactions and material disintegrations in AIBs. The new findings reported here highlight the possibility for designing high‐performance cathode materials for scalable and flexible AIBs.
Binder‐free and free‐standing cobalt sulfide@carbon nanotubes are applied as the cathode for aluminum‐ion batteries with enhanced electrochemical performance. The optimized electrode exhibits a high capacity (315 mA h g−1 at 100 mA g−1), excellent rate performance, and remarkable cycling stability (297 mA h g−1 at 100 mA g−1 after 200 cycles; 87 mA h g−1 at 1 A g−1 after 6000 cycles).
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