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Context The value realization of the ecosystem services (ES) with directional ecosystem service flows (ESF) is sensitive to the way ES supply and demand are spatially coupled, of which the nature of the propagation dynamics of ESFs and the mechanisms of effective demand generation remain to be clarified.Objectives The paper focuses on a typical directionally flowed urban ES, the park-recreational service, and proposes a formal model for analyzing its ES value realization mechanism, which discerns the ES value contribution of distance-decaying ES supply from the that of the demand-side factors. A cellular big-data supported empirical study conducted in Ningbo, China is conducted as a case illustrating the application of the model.Methods Statistical physical analysis on people’s park visitation behavior is performed to uncover the distance decay patterns of recreational ESF propagation. Further, with the conceptualization of the ES-consuming propensity, which captures the demand-side factors influencing effective ES demand generation including population demographics, socio-economic status, and urban place semantics, we construct spatial regression models that explain these factors’ contributions in ES value realization.Results The statistical physical analysis reveals both universality and park type-specific idiosyncrasies in the ESF distance decay patterns, corroborating the findings in previous studies. The spatial regression models yield up to 80% explanatory power, and results show that the ES-consuming propensity accounts for one quarter of the variation of realized ES value, with endogenous factors dominating effective ES demand generation while exogenous factors less influential.

A high incidence of bone defects and the limitation of autologous bone grafting require 3D scaffolds for bone repair. Compared with synthetic materials, natural edible materials possess outstanding advantages in terms of biocompatibility, bioactivities and low manufacturing cost for bone tissue engineering. In this work, attracted by the natural porous/fabric structure, good biocompatibility and bioactivities of the lotus root, the lotus root-based scaffolds were fabricated and investigated their potential to serve as natural porous bone tissue engineering scaffolds. The results indicated that the lotus root-based scaffolds possess suitable natural microstructure, excellent biocompatibility and promising functions, such as antioxidant capacity and angiogenesis promotion. Remarkably, lotus root scaffolds showed encouraging possibility of bone tissue engineering while the mineralized lotus root could further improve the bone regeneration in vivo. All the results demonstrated the bone regeneration potential of lotus root-based scaffolds equipped with suitable natural architecture, excellent biocompatibility, specific bioactivities and low manufacturing cost.

Power conversion efficiency (PCE) of perovskite solar cells (PSC) has been skyrocketed to certified 25.5% owing to their improved and tunable optoelectronic properties. Although, various strategies have been adopted to date regarding PCE and stability enhancement within PSC technology, certain instability factors (moisture, heat, light) are hindering their commercial placement. Recently, all-inorganic PSCs got hype in the photovoltaic research community after they attained PCE > 20% and due to their significant endurance against heat and light mishmashes, but there only left moisture sensitivity as the only roadblock for their industrial integration. Here, we review the recent progress of additive inclusion into all-inorganic (CsPbX3) PSCs to stabilize their intrinsic structure and to withstand the performance limiting factors. We start with the detailed description of chemical instability of different perovskite compositions, phase segregation, and how organic molecules and dyes help to repair the structural defects to improve the overall PCE and stability of PSCs. Moisture endurance as a result of chemical passivation through organic additives, low-dimensional inorganic PSCs to enhance device stability and scalable fabrication of CsPbX3 PSCs are also reviewed. The challenges of module degradation and design implications with proposed strategies and outlook are interpreted in the ending phrases of this review.

Perovskite solar cells (PSCs) are attracting much attention and are on the way to commercialization. However, some modules are subject to reverse bias in actual fields, so it is meaningful to investigate the reverse-bias behavior of PSCs. Herein, an in-situ temperature and current measurement technique was developed. Intriguingly, some hot spots were observed and then quickly disappeared in the reverse biased PSCs, along with the simultaneous increase in the current and local temperature. Also, the potential mechanism has been revealed and analyzed. An abnormal bulge in the perovskite film was found at the hot spot. Accordingly, the appearance and disappearance of hot spots were perfectly explained by band bending and tunneling current caused by ion accumulation. Additionally, statistical analysis suggested that sparkling hot spots were related to reverse voltage and efficiencies of PSCs. The research provides a great significance for the study of PSCs under reverse bias.

Methylammonium (MA)-free perovskite solar cells have the potential for better thermal stability than their MA-containing counterparts. However, the efficiency of MA-free perovskite solar cells lags behind due to inferior bulk quality. In this work, 4-methylphenethylammonium chloride (4M-PEACl) is added into a MA-free perovskite precursor, which results in greatly enhanced bulk quality. The perovskite crystal grains are significantly enlarged, and defects are suppressed by a factor of four upon the incorporation of an optimal concentration of 4M-PEACl. Quasi-2D perovskites are formed and passivate defects at the grain boundaries of the perovskite crystals. Furthermore, the perovskite surface chemistry is modified, resulting in surface energies more favorable for hole extraction. This facile approach leads to a steady state efficiency of 23.7% (24.2% in reverse scan, 23.0% in forward scan) for MA-free perovskite solar cells. The devices also show excellent light stability, retaining more than 93% of the initial efficiency after 1000 h of constant illumination in a nitrogen environment. In addition, a four-terminal mechanically stacked perovskite-silicon tandem solar cell with champion efficiency of 30.3% is obtained using this MA-free composition. The encapsulated tandem devices show excellent operational stability, retaining more than 98% of the initial performance after 42 day/night cycles in an ambient atmosphere.

Oxidative stress and infection are the main reasons for postponement of wound healing rate. They can potentially lead to serious inflammation and eventually lead to a longer and more painful recovery phase. Although wound dressings based on synthetic materials with antioxidative property have been proved to exhibit remarkable effect in controlling ROS level and improving wound healing, issues, such as high cost in raw materials, complicated procedures, usage of various toxic additives, and potential allergies, have significantly confined further clinical applications. In this study, a novel type of tissue engineering scaffold, based on tomatoes (Solanum lycopersicon) and gelatin methacryloyl (GelMA), was prepared via facile lyophilization and photo cross-link method (SL/GelMA). By taking advantages of various antioxidative components, such as carotenoids, flavonoids, phenolic acids, vitamin E, and vitamin C in tomatoes, SL/GelMA can effectively regulate ROS level, relieve the oxidative stress in wound bed, promote cell migration and angiogenesis, contribute to collagen deposition, and thus accelerate the rate of wound enclosure. Along with its high biocompatibility and low allergic potential, we believe that the food-derived wound dressing with facile preparation method, easy accessibility, and high cost-effectiveness can be translated for clinical treatments of various chronic wounds.

Perovskite devices have been developed rapidly over the past decade and all‐inorganic perovskite devices have attracted wide interest due to their outstanding stability. The crystallization process and microstructures of inorganic perovskite play important roles on the device performance. Herein, synchrotron radiation grazing incidence X‐ray diffraction (GIXRD) was utilized to investigate the microstructure evolution of CsPbI2Br all‐inorganic perovskite film during post annealing, as well as its influence on the performance of CsPbI2Br perovskite solar cells (PSCs). It was found that high‐temperature (240°C) flash annealing accelerated the precursor solution to rapidly crystallize within a few seconds and reduced the generation of non‐perovskite phase. The centroid and full‐width at half‐maximum (FWHM) of perovskite diffraction peaks, corresponding to lattice constant and crystallite size of perovskite, respectively, changed gradually with the flash annealing time. The flash annealing time was optimized to be 10 seconds, leading to the suitable microstructure and crystallite size, as well as the best photovoltaic performance of PSCs. These results indicate that the microstructure evolution of all‐inorganic perovskite film during the post flash annealing plays a key role in the device performance.

Biomimetic scaffolds present the promising potential for bone regeneration. As a natural gel-like traditional food, tofu with porous architecture and proved biological safety indicated a good potential to be a natural scaffold and easy to be improved by surface modification. Hereon, we fabricated the tofu-based scaffolds and systematically explored the potential for bone tissue engineering. In addition, the collagen has been introduced by simple coating to further enhance the surface compatibility of the tofu-based scaffold in bone regeneration. The results showed that the tofu-based scaffolds possessed good porous structure and cytocompatibility. Notably, the tofu-based scaffolds could improve the expression of osteogenesis-related genes and proteins, leading to better bone regeneration after 2 months of implantation. All the results indicated that tofu would become an outstanding sustainable natural porous scaffold for bone regeneration with excellent bioactivities.

Flexible solar cells are promising for space applications due to their unique properties including lightweight and flexibility. In particular, flexible perovskite solar cells (f-PSCs) with high eff...

To overcome the low mechanical strength and difficult bonding of hydrogels to bones which are the major limitations of hydrogels used in bone-regeneration, a new type of calcium polyphosphate incorporated into bioinspired alginate/polyacrylic acid (CPP/PAA-Alg) hybrid double network (DN) hydrogel with both high strength and enhanced osseointergration was prepared by a two-step polymerization with alginate and polyacrylic acid for bone regeneration. The morphology, mechanical properties, swelling, biocompatibility, osseointegration and osteogenic ability of this CPP/PAA-Alg DN hydrogel were investigated. The results show that CPP/PAA-Alg DN hydrogel with highly porous microstructure possesses high water absorption capacity and highly strength properties which meet the requirements of bone repairing. The results of in vitro studies revealed that the CPP/PAA-Alg DN hydrogels can support the spread of cells and promote the cell proliferation. Animal studies demonstrated that the CPP incorporated would enhance the osseointegration of DN hydrogel with host bone at an early stage after implantation to accelerate the regeneration of bone. This research may provide a new way to develop biocompatible biomaterials with high mechanical strength and good osseointegration to meet the needs of bone regeneration.

Food-derived materials possess inherent advantages in tissue engineering applications with appropriate biosafety, availability, and maneuverability. This work takes advantage of gelatin methacrylate (GelMa) to fabricate the tofu-incorporated hydrogels and systematically investigated the potential for bone regeneration. The results affirmed that tofu-incorporated hydrogel possessed porous architecture, satisfactory mechanical performance, and appropriate cytocompatibility. It is worth noting that little inflammation could be caused by the tofu/GelMa hydrogels, and the incorporated tofu powder could also promote the secretion of osteogenesis and immune-related cytokines in the early stage, resulting in improved bone regeneration during the 2-month implantation. All the results suggested that tofu/GelMa hydrogels possessed good potential for bone regeneration with low cost, satisfactory cytocompatibility, and excellent bioactivity.

The past years have witnessed promising clinical feedback for anti-cancer immunotherapies, which have become one of the hot research topics; however, they are limited by poor delivery kinetics, narrow patient response profiles, and systemic side effects. To the best of our knowledge, the development of cancer is highly associated with the immune system, especially the tumor immune microenvironment (TIME). Based on the comprehensive understanding of the complexity and diversity of TIME, drug delivery strategies focused on the modulation of TIME can be of great significance for directing and improving cancer immunotherapy. This review highlights the TIME modulation in cancer immunotherapy and summarizes the versatile TIME modulation-based cancer immunotherapeutic strategies, medicative principles and accessory biotechniques for further clinical transformation. Remarkably, the recent advances of cancer immunotherapeutic drug delivery systems and future prospects of TIME modulation-based drug delivery systems for much more controlled and precise cancer immunotherapy will be emphatically discussed.

Designing biomimetic scaffolds that can provide an appropriate microenvironment in bone defects to accelerate bone regeneration may become the breach of bone tissue engineering. Herein, we present simple egg white (EW)-/eggshell (ES)-based biomimetic hybrid hydrogels to investigate their potential for promoted bone regeneration. The photopolymerized biomimetic hybrid hydrogels possessed porous structures, which may support cell growth. Remarkably, the addition of eggshells could benefit mechanical performance with good cytocompatibility. Moreover, biomimetic hybrid hydrogels could have effects on macrophages and regulate the osteogenic differentiation of human dental pulp stem cells, indicating their potential for enhanced bone regeneration. All of the results suggested that biomimetic hybrid scaffolds possess a promising prospect in bone tissue engineering with good bioactivity and low cost.

Perovskite solar cells (PSCs) have been developed rapidly in recent years, representing the most promising candidates for photovoltaics. Regarding their application in spacecraft, it is essential to exploring the space radiation tolerance of PSCs. In this paper, the mechanism of performance degradation of ternary cation (methylammonium (MA), formamidinium (FA) and cesium (Cs)) lead trihalide perovskite planar heterojunction (PHJ) solar cells under gamma-ray radiation was analyzed layer by layer. The results demonstrate that PSCs experience obvious performance degradation under gamma-ray irradiation, especially undergoing apparent recession of short-circuit current density (Jsc) and accordingly power conversion efficiency (PCE). They are mainly attributed to the phase transition of perovskite films and the color appearance of the glass substrate induced by the irradiation, deteriorating the perovskite film absorbance and the substrate transmittance. These results serve as a strong necessity to improve the stability of PSCs for the future application in aerospace.

Bone regeneration remains a clinical challenge with limited bone substitutes, urging for effective alternative strategies. Nanotubes, especially carbon nanotubes and titanium dioxide nanotubes, have been widely utilized for bone regeneration; however, their further applications were limited by the composition and degradability. As naturally occurring aluminosilicate nanoclay, halloysite nanotubes (HNTs), with good biocompatibility, functionality, and nanotubular structures, may be a promising platform for promoting bone regeneration. Herein, we presented a HNTs incorporated hydrogel and explored the potential bone tissue engineering applications of HNTs. The HNTs encapsulated hydrogel was simply fabricated by using the photopolymerization method with gelatin methacrylate (GelMA) and HNTs. The incorporation of HNTs led to an enhanced mechanical performance while maintaining a good cytocompatibility in vitro. The osteogenic activities of the HNTs incorporated platform have also been studied in vitro and in vivo. Remarkably, the addition of HNTs obviously upregulated the expression of osteogenic differentiation-related genes and concomitant protein of human dental pulp stem cells (hDPSCs) and therefore facilitated subsequent bone regeneration in calvarial defects of rats. Overall, the results obtained in this study highlight the bone regeneration capacity of HNTs, which may enhance current understanding of HNTs, and present a promising alternative strategy for bone regeneration.

To development biomimetic strategy for enhanced cancer therapy, the paclitaxel loaded egg white/sodium alginate nanoparticles were prepared by electronic spray method. Their appearance and particle size were observed by transmission electron microscope and particle size analyzer. The drug release behavior of nanoparticles was determined by high performance liquid chromatography (HPLC). The toxicity, morphology and interaction of nanoparticles to cells were studied by means of MTT, live/dead staining and laser scanning confocal microscopy. The results show that the nanoparticles have good particle size dispersion, regular morphology, good drug release performance, good biocompatibility and in vitro effective inhibition of CT26 colorectal cancer cells. These results demonstrated that the good biocompatibility of egg white coated sodium alginate nanoparticles and PTX loaded these nanoparticles would show potential application for cancer therapy.

To design and prepare a novel controlled release system for sustained release of two drugs. In this study, a double-layer microsphere was incorporated with strontium-doped calcium polyphosphate (SCPP) scaffold to facilitate bone regeneration and achieve skull repair. The double-layer microsphere combining tetracycline loaded sodium alginate and matrix metalloproteinase-2 (MMP-2) loaded chitosan was manufactured by electrospinning, which were further adhered to SCPP scaffold. The characteristics of microstructure were observed through scanning electron microscope. Loading efficiencies and the optimal ratio of microsphere of the obtained controlled release system were investigated. In addition, the cytotoxicity and the effects on osteoblast proliferation and expressions of osteogenesis-related factors were examined in vitro. Thereafter, the compound material with the controlled release system was implanted in the skull defect of rabbit to evaluate its properties of promoting bone regeneration. The results indicated that this novel controlled release system with SCPP scaffold and the double-layer microspheres loaded with tetracycline and MMP-2 could be a promising material for bones repair.

In this study, a strong and tough high-density polyethylene (HDPE)/hydroxyapatite (HA) nanocomposites with bone-analogues structure was successfully prepared via a simple dynamic-oscillation-shear processing method for biomedical application as bone substitute materials. Dynamic-oscillation-shear flow field was applied by self-made loop oscillatory push-pull molding (LOPPM) equipment. The LOPPM-processed HDPE/HA composites exhibited tremendous increase of tensile strength, modulus and toughness up to 95.1 MPa, 4.2 GPa, 58.4 kJ/m2, respectively, which could be attributed to better dispersion of HA in HDPE matrix and highly ordered shish-kebab structure as evident from DSC, SEM, WAXD and SAXS studies. Meanwhile, the formed hierarchical structure not only showed bone-like structure, but also endowed composites with high strength, modulus and toughness, even close to the human cortical bone. Moreover, in vitro cell culture study was performed on NIH-3T3 fibroblast cells to evaluate the biocompatibility of the composites. The results showed that the produced bone substitutes exhibit good biocompatibility. Besides, using a rabbit calvarial defect model, in vivo testing has shown that a strong and stable interface is developed between the composites and the host bone. Overall, we present a facile and green strategy to generate polymer composites with high strength and toughness and the produced LOPPM-processed HDPE/HA polymer nanocomposites have a great potential for use as load-bearing bone substitute in biomedical application.

Gelatin methacryloyl (GelMA)-based biomaterials have been widely used in various biomedical applications due to their suitable biological properties and tuneable physical characteristics. In particular, GelMA can be used as a versatile matrix for bone tissue engineering scaffolds via various strategies to overcome major obstacles such as insufficient mechanical property and uncontrollable degradation. This review presents the research status of GelMA, its structure and function, GelMA-based biomaterials and the development of methods along with their existing challenges.

Interfacial defects greatly influence the performance of perovskite solar cells (PSCs), and interface engineering is a powerful technique to promote the power conversion efficiency (PCE) of PSCs. Herein, an interfacial passivation strategy is developed employing cesium fluoride (CsF) to modify the surface of a perovskite film. Theoretical calculations suggest that the Cs+ and F− ions have a targeted passivation effect to decrease the defect density of the perovskite. Meanwhile, Cs+-formamidine+ (FA+) and F−–I− ion exchange can occur on the perovskite surface, which leads to the decline of the Fermi level of perovskite and reinforces the built-in potential of PSCs. Additionally, experiment results also confirm the reduction in the interfacial defects and the enhancement of the built-in potential. Consequently, the open-circuit voltage ( Voc) of PSCs is increased from 1.07 to 1.12 V, contributing to the promotion of the PCE. Furthermore, the stability of PSCs is obviously improved as well owing to the suppressed phase transition of α-phase perovskite. Our findings provide guidelines for surface modification of perovskite crystals to enhance the performance and stability of PSCs.

Organic–inorganic hybrid perovskite solar cells (PSCs) are developing rapidly, but most of the PSCs are prepared by spin coating process, which is not compatible with potential large-scale, high-throughput industrialization. Slot-die coating is a promising deposition technique with high precision and excellent material utilization, which can accelerate the industrial-scale production of PSCs and enhance the potential commercial value. Herein, fully slot-die-coated PSCs were achieved by subsequently slot-die coating electron transport layer, perovskite layer and hole transport layer in ambient condition, leading to a power conversion efficiency (PCE) up to 14.55%. The optimization of slot-die coating parameters for two-step deposition process can produce even PbI2 film and subsequent high-quality perovskite film. Furthermore, a mixed solvent of dimethyl sulfoxide and N, N-dimethylformamide was used to dissolve PbI2 for further enhancing the surface energy and delaying crystallization, leading to a uniform and better perovskite film. In addition, the slot-die coating properties and repeatability could be improved by adding a small quantity of cations (cesium, methylammonium and formamidinium) additives into the PbI2 precursor solution. The results suggest that efficient PSCs with good repeatability could be processed via fully slot-die coating in ambient condition, which is compatible with potentially large-scale, roll-to-roll commercial process.

Tofu not only is a delicious vegetarian food, but also shows potential biomedical applications for its high protein content and typical porous scaffold structure. Herein, two kinds of porous soybean scaffolds were developed, the first based on the traditional tofu manufacturing processes, the second modified via covalent crosslinking. The morphology, physicochemical properties and biocompatibility in vitro and in vivo were systematically investigated. A similar porous micromorphology was observed in both the tofu scaffolds and crosslinked soybean protein scaffolds. Both scaffolds exhibited good cell proliferation and cellular adherence. No obvious inflammatory response was observed after subcutaneous implantation tests for either material. These results demonstrated that the tofu scaffolds or soybean protein scaffolds fabricated by tofu processing have potential as new food-source biomaterials in tissue engineering applications.

Three-dimensional (3D) bio-nanocomposite poly (butylene succinate) (PBS)/cellulose nanocrystals (CNC) scaffolds were fabricated by a solvent mixture of chloroform (CF) and methanol (MeOH) via electrospinning technique. Morphological, thermal, mechanical, and hydrophilicity as well as in vitro degradation and biocompatibility properties of the electrospun fibrous bio-nanocomposite scaffolds were investigated. Scanning electron microscopy (SEM) indicated that the average diameter of the electrospun fibers decreased with increase in CNC concentration. The incorporation of CNC not only enhanced the thermostability, and 0.5 wt% and 1 wt% CNC significantly increased the crystallinity of PBS matrix, but also improved the tensile strength, Young's modulus and hydrophilicity of PBS matrix with an optimum 3 wt% CNC. Moreover, it also improved the porosity and decreased the density of the PBS/CNC scaffolds. In vitro degradation results showed that PBS/CNC3 scaffold had better bio-degradation ability, from 4.5% of neat PBS to 13.74% of PBS/CNC3 in 28 days. 3T3 fibroblast cell culture was performed to confirm the good biocompatibility of the scaffolds. Cells were found to proliferate better on the PBS/CNC3 scaffolds, as compared to neat PBS scaffolds in 7 days.

BACKGROUND For safe and effective therapy, drugs are supposed to be actively targeted at the desired disease locations. As a promising candidate for drug delivery, long circulating system with various strategies has been widely used. Recently, biomimetic strategies mediated long circulation of drug delivery system have been increasingly developed for forming various nanoparticles and shown the anticipated potential. METHOD In this review, a variety of approaches for long circulation strategy have been surveyed, together with different modifications. The future perspectives as well as challenges in this field are also discussed. RESULTS Amounts of papers from nearly 5 years were included in the review, this review identified PEGylation, liposomal, biomimetic materials were the effective strategy for drug long circulation. CONCLUSION The findings of this review confirm the importance of long circulation for drug delivery. Designing of a delivery system requires an appropriate balance between the stability of material and the long term circulation in body, which can be tailored to a specific application, based on experience optimization and customized design. Biomimetic design strategy is likely to revolutionize the current medical condition. In the medical field, using these emerging technologies on materials is promising to improving the traditional modalities and achieving novel applications on long circulation of delivery systems.

It is highly desirable to develop large-scale, low-cost fabrication techniques to process perovskite solar cells (PSCs) under ambient condition for accelerating their potential commercialization. Herein, efficient planar heterojunction (PHJ) PSCs with a simple structure of ITO/NiOx/CH3NH3PbI3 (MAPbI3)/PC61BM/Ag is fabricated via fully doctor blading under ambient condition with the humidity of ∼40%, in which the NiOx layer, MAPbI3 layer, and PC61BM layer are deposited via doctor blading subsequently. The high-quality perovskite CH3NH3PbI3 films are fabricated by one-step doctor-bladed deposition using modified precursors with the co-solvents of dimethylsulphoxide (DMSO) and dimethylformamide (DMF) along with the suitably excess MAI. The well control on solvent recipe retards the crystallization time, leading to the formation of homogeneous and uniform perovskite film with large-size domains. Furthermore, the excess MAI in the modified precursor ink is helpful to form large-size perovskite grains and high crystallinity. With the optimization, the fully doctor-bladed PHJ-PSCs under ambient condition with the power conversion efficiency (PCE) up to 10.92% is achieved, yielding an average PCE of 10.16%. The research suggests that solvent engineering is a good route for fabricating high-quality perovskite films via one-step, doctor-blading deposition, and it is feasible to achieve efficient PHJ-PSCs through fully doctor-balding technique under ambient condition.

The quality of perovskite film plays an important role on the performance and stability of perovskite solar cells (PSCs). Herein, dense and uniform perovskite (CH3NH3PbI3) films are fabricated by combining hot-casting technique (HCT) and methylamine (CH3NH2) gas treatment (MGT) under ambient conditions with a relative humidity of about 60%. These high quality CH3NH3PbI3 films are further used to fabricate planar heterojunction (PHJ) PSCs with a structure of ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Ag, showing a power conversion efficiency (PCE) up to 14.2% with negligible hysteresis. More importantly, these PHJ-PSCs show excellent stability, and over 80% of their original efficiencies could be maintained even stored in air (humidity ∼45%) for 20 days without encapsulation. Meanwhile, the PCE up to 13.6% could be achieved for PHJ-PSCs fully fabricated in air including electron transport layer PCBM. The researches provide an ease-of-fabrication method to fully fabricate highly efficient and stable PHJ-PSCs under ambient conditions with high humidity, which would potentially accelerate the commercialization of PHJ-PSCs.

Metal halide perovskites (MHPs) show excellent optoelectronic properties and exhibit great potential applications in optoelectronic devices, such as solar cells (SCs), photodetectors, light-emitting diodes (LEDs), lasers, and so on. Vapor-phase synthesis provides an important way to grow large-scale, high-quality MHP thin films and micro-/nanostructures, exhibiting wide applications in constructing all kinds of optoelectronic devices. In this review, we systematically summarize the growth of perovskite thin film and the nano-/microstructure by vapor-phase synthesis. The detailed classification of vapor-phase synthesis is first introduced, and the effects of the substrates on the growth process are discussed subsequently. Then, the applications of perovskite thin films and micro-/nanostructures grown by vapor-phase synthesis in SCs, photodetectors, LEDs, lasers, and so forth, are discussed in detail. Finally, the conclusions and outlook are presented.

Thermal plastic polyurethanes (TPUs), serving as biomaterials, have become increasingly prevalent over time in many fields including artificial blood vessels, pericardial patches and other tissue engineering scaffolds by virtue of well adjustable performance. However, synthetic polyurethanes are, to some extent, inadequate for their cytocompatibility and biological activity owing to high hydrophobicity and lack of active groups. In this study, an amino-terminated bis(L-arginine) alkylene diester extender (L-Arg-8) was synthesized and Arg-based biodegradable poly(ester urea) urethanes (PEUUs) with different content of arginine groups were designed, synthesized and characterized in regard to the amelioration of the biodegradability, hydrophilicity and cytocompatibility of thermoplastic polyurethanes (TPUs) with PCL as soft segments. Biodegradability, hydrophilicity and positive surface charges increased after Arginine was introduced. As cytocompatibility was improved, PEUU materials A8-1.2 and A8-1.6 were proved to be suitable for human dental pulp stem cells (hDPSCs) to adhere, grow and proliferate on in vitro. These materials would unlock great potential for the use in tissue engineering and regeneration. Additionally, halloysite nanotubes (HNTs) were composited to PEUUs for further exploration to the applications in bone tissue. The addition of halloysite nanotubes further stimulated the osteogenic differentiation of human dental pulp stem cells in vitro. At the same time, a rat cranial defect model was built to assess effects of repair in vivo. Osteointegration and repair were promoted by patch-implanted groups. A8-1.2 6% HNTs showed the best repair. All the results indicated that Arg-based poly(ester urea) urethanes and the composites were conductive to bone repair.

Effective bone regeneration remains a challenge for bone-tissue engineering. In this study, we propose a new strategy to accelerate bone regeneration via a sustained supply of phosphorus without providing foreign calcium. Herein, a black phosphorus nanosheet (BPN)-based hydrogel platform was developed, and the BPNs were used to stably and mildly provide phosphorus. The hydrogel was fabricated by photo-crosslinking of gelatin methacrylamide, BPNs, and cationic arginine-based unsaturated poly(ester amide)s. This platform combines the following advantages: the hydrogel scaffold would keep BPNs inside, and the encapsulated BPNs can degrade into phosphorus ions and capture calcium ions to accelerate biomineralization in a bone defect. The introduction of BPNs helped to enhance the mechanical performance of hydrogels, photoresponsively release phosphate, and accelerate mineralization in vitro. Moreover, BPN-containing hydrogels improved osteogenic differentiation of human dental pulp stem cells via the bone morphogenic protein-runt-related transcription factor 2 pathway. In vivo results from a rabbit model of bone defects revealed that the BPNs helped to accelerate bone regeneration. All these results strongly suggest that the strategy of a sustained supply of calcium-free phosphorus and this BPN-containing hydrogel platform hold promise for effective bone regeneration.

Flexible perovskite solar cells (f-PSCs) have been attracting tremendous attention due to their potentially commercial prospects in flexible energy system and mobile energy system. Reducing the energy barriers and charge extraction losses at the interfaces between perovskite and charge transport layers is essential to improve both efficiency and stability of f-PSCs. Herein, 4-trifluoromethylphenylethylamine iodide (CF3 PEAI) is introduced to form a 2D perovskite at the interface between perovskite and hole transport layer (HTL). It is found that the 2D perovskite plays a dual-functional role in aligning energy band between perovskite and HTL and passivating the traps in the 3D perovskite, thus reducing energy loss and charge carrier recombination at the interface, facilitating the hole transfer from perovskite to the Spiro-OMeTAD. Consequently, the photovoltaic performance of f-PSCs is significantly improved, leading to a power conversion efficiency (PCE) of 21.1% and a certified PCE of 20.5%. Furthermore, the long-term stability of f-PSCs is greatly improved through the protection of 2D perovskite layer to the underlying 3D perovskite. This work provides an excellent strategy to produce efficient and stable f-PSCs, which will accelerate their potential applications.

Organic-inorganic hybrid perovskite solar cells (PSCs) are continuously attracting much attention due to the poential applications in low-cost and flexible solar energy system. In this work, potassium (K+) and cesium (Cs+) were added into the perovskite (FAMA)Pb(IBr)3 (FA = CH(NH2)2+, MA = CH3NH3+) to prepare the high-quality quadruple-cation (KCsMAFA) perovskite film and PSCs via two-step solution process. The optoelectronic properties and stability of FAMA, CsFAMA and KCsFAMA perovskite film and PSC devices were systematically studied and analyzed. The power conversion efficiency (PCE) of champion KCsFAMA device reached 19.70%, and the steady output PCE was 19.40% with a simple device structure of ITO/SnO2/Perovskite/Spiro-OMeTAD/Ag. In addition, the stability of PSCs with quadruple-cation KCsMAFA was significantly improved as compared to the control ones. With the storage in air for 20 days (humidity ∼35%), the PCEs of PSCs without encapsulation could maintain 77% of the initial values, while the PCEs of PSCs with MAFA and CsMAFA only maintained 39% and 56% of their initial values, respectively. The improved efficiency and stability in PSCs with both K+ and Cs + were attributed to significant improvement in the film quality with large and dense grains, which could reduce grain boundaries and moisture immersion. Meanwhile, the incorporation of K+ and Cs+ could enhance the charge transfer resistance and suppress the charge recombination effectively, supporting in the improvement in the performance of PSCs.

Organic solar cells (OSCs) have been attracting considerable interest due to their unique advantages of low cost, light weight, and especially mechanical flexibility. The low-cost and high-throughput techniques matching with the large-scale and roll-to-roll (R2R) process for fabricating efficient OSCs in the ambient condition would greatly accelerate the potential commercialization of OSCs. Herein, we demonstrate that the fabrication processes of OSCs using the bulk heterojunction (BHJ) composed of poly[(2,6–(4,8-bis(5–(2-ethylhexy)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5–(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′5′-c′]dithiophene-4,8-dione))] (PBDB-T) and 3,9-bis(2-methylene-(3–(1,1-dicyanomethylene)-5-methylindanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]-dithiophene (IT-M) are transferred from a glovebox to the ambient condition, where the deposition of doctor blading instead of conventional spin coating is investigated. The morphology, microphase separation, and crystallinity of BHJ PBDB-T:IT-M are dramatically influenced by the fabrication processes. The OSCs with a structure of ITO/ZnO/PBDB-T:IT-M/MoO3/Ag fabricated via doctor-blading in the ambient condition show a power conversion efficiency (PCE) of 9.0% as compared to conventional spin-coated OSCs in a glovebox with a PCE of 11.91% and in the ambient condition with a PCE of 9.91%. These results suggest that efficient OSCs could be processed in the ambient condition by large-scale and low-cost doctor-blading, which can be compatible with the R2R manufacturing process.

It is very meaningful to develop large-scale, low-cost technology for fabricating efficient perovskite solar cells (PSCs) to accelerate their commercialization. Doctor-blading is one of important scalable technologies for processing PSCs, but the power conversion efficiencies (PCEs) of fully doctor-bladed PSCs, including electron transport layer, perovskite layer and hole transport layer, are still lag far behind the PSCs fabricated via conventional spin-coating technology, especially fabricated in ambient condition. Herein, highly efficient planar heterojunction PSCs with a structure of ITO/SnO2/FAxMA(1-x)PbIyBr(3-y)/Spiro-OMeTAD/Ag are achieved by fully doctor-blading technique in ambient condition, in which high-quality perovskite films with low trap-density are fabricated via two-step sequential deposition with a low temperature process by simultaneously introducing composition engineering and additive-doping technology. Organic cation is added into the PbI2 precursor to reduce the uneven distribution of nucleation sites in the perovskite films during doctor-blading process and promote the uniform growth of perovskite grain. Moreover, 2,3,5,6-tetrafluoro-7,7,8,8-tetra-cyanoquinodimethane (F4-TCNQ) acted as the doping additive is employed into perovskite, resulting in healing the perovskite grain boundary and reducing trap-density accordingly. As a result, the doctor-bladed PSCs fabricated in ambient condition exhibit the champion PCE of 18% and a stabilized efficiency of 17.7%. Furthermore, PSCs fabricated via fully doctor-blading in ambient condition achieve the PCE of 17.0% with negligible hysteresis. This work provides an important strategy for scalable fabrication of efficient PSCs in ambient condition and potentially accelerates the commercialization.

The morphology and interface of perovskite film are very important for the performance of perovskite solar cells (PSCs). The quality of perovskite film, fabricated via two-step spin-coating process, is significantly influenced by the morphology and crystallinity of PbI2 film. With the addition of additive dimethyl sulfoxide (DMSO) into the PbI2 precursor, the roughness and trap-state density of perovskite film have been significantly reduced, leading to the excellent contact between perovskite layer and subsequent deposited carrier transport layer. Accordingly, the planar heterojunction PSCs with an architecture of ITO/SnO2/perovskite/PTAA/Ag show an efficiency up to 19.02%. Furthermore, PSCs exhibit promising stability in air with a humidity of ∼ 45%, and retain 80% of initial efficiency after being exposed to air for 400 h without any encapsulation.

Bone transplantations are still facing many serious challenges, hydrogel as a new kind of artificial bone substitutes has developed into a promising bone scaffold material. However, it is still a challenge to combine bioactive agents and hydrogel matrix to promote osteoinductivity. Herein, we developed a novel bioactive hydrogel based on arginine-based unsaturated poly (ester amide) (Arg-UPEA) and methacrylated hyaluronic acid (HA-MA) via photo-crosslinking. As the results indicated, we found that the introduction of Arg-UPEA into HA-MA hydrogels could finely modulate their compressive modulus, swelling level and porous structure. Besides, among groups of different feed ratio, groups of 10 % and 15 % of Arg-UPEA content effectively enhanced osteogenic differentiation in osteoblasts when compared with HA-MA hydrogel. Furthermore, better bone regeneration and expression of osteogenesis-related factors in vivo also verified the Arg-UPEA/HA-MA hybrid hydrogels as a promising scaffold material for bone tissue engineering.

After a biomaterial is implanted in a bone defect area, the immune response and bacterial infection affect the success of bone regeneration. In this study, we describe the development of a promising therapeutic approach to accelerate bone regeneration via combining osteoimmunomodulatory and antibacterial activities. Herein, we fabricated a nanosilver/halloysite nanotubes/gelatin methacrylate (nAg/HNTs/GelMA) hybrid hydrogel and evaluated its osteoimmunomodulatory and antibacterial properties in vitro and in vivo. The nAg/HNTs/GelMA hybrid hydrogel had good biocompatibility with human periodontal ligament stem cells (hPDLSCs) and macrophages. Moreover, the nAg/HNTs/GelMA hybrid hydrogel modulated inflammatory cytokines secreted by macrophages and enhanced the osteogenic differentiation of hPDLSCs in an inflammatory environment. In addition, nAg/HNTs/GelMA hybrid hydrogel inhibited the growth of Gram-positive and Gram-negative bacteria in vitro and in vivo. Compared with HNTs/GelMA hydrogel, the nAg/HNTs/GelMA hybrid hydrogel better modulated the osteoimmune microenvironment and eliminated bacterial infection. Thus, this hybrid hydrogel combining osteoimmunomodulatory with antibacterial activities is a promising biomaterial for bone regeneration in defect areas.

Increasing the energy density without sacrificing power density is a key technical problem all the time that hinders the further application of supercapacitor. A good electrical conductivity electrode determines whether the supercapacitor can be charged–discharged at the high current density and the electric energy stored can be effectively utilized. Silver nanowires (AgNWs) acted as an electrode material in supercapacitor not only improve the electrical conductivity, but also enhance the mechanical stability. Here, we provide a simple and low-cost way to effectively improve the conductivity of carbon electrode by adding suitable AgNWs dispersed in alcohol. A single cell with a composite electrode composed of activated carbon (AC) and 4% AgNWs has a capacitance of 215 F g− 1, an excellent rate performance of 75% at 10 A g− 1, and a good cycling stability after 5000 cycles, showing a great improvement compared with bare AC. The results suggest that the composite electrode composed of AC and AgNWs have a great potential application in supercapacitor commercialization.

Ischemia-reperfusion (I/R) is a major cause of acute kidney injury (AKI), which is associated with unacceptably high mortality rates in ICU. This research was designed to explore the therapeutic effect of BAPTA-AM (1,2-Bis(2-aminophenoxy) ethane-N,N,N,N-tetraacetic acid tetrakis(acetoxymethyl ester)) nanoparticle (BA-N) on AKI. BA-N was developed by liposome strategy and characterized by standard methods. The rat model was selected and the rats were randomly allocated into four groups: (1) Normal group; (2) Sham-operated group; (3) Model group (I/R + NS); (4) BA-N treatment group (I/R + BA-N). AKI model was established via clipping the bilateral renal artery with a microvascular clamp for 45 min. After reperfusion, serum cystatin C (Cys C), creatinine (Cr), blood urea nitrogen (BUN), lactate dehydrogenase (LDH) and caspase 3 levels were determined for the assessment of renal function. Kidney samples were then collected for the measurement of renal malondialdehyde (MDA) level and superoxide dismutase (SOD) activity. The assays of histological examination, ELISA, immunohistochemistry, western blot, TUNEL and RT-PCR were utilized for the detection of apoptosis. The results demonstrated that AKI model caused a significant decreasing in SOD activity, accompanied by a remarkable increase in Cys C, Cr, BUN, LDH, MDA, caspase 3 and cytochrome c (Cyt C) level, compared to the control group. BA-N (100 μg/kg i.v.) significantly improved renal function and histopathological appearance, restored MDA level and SOD activity, decreased Bax/Bcl-2 ratio, caspase 3 activity, Cyt C release and TUNEL positive apoptotic cells. Our studies indicated that BA-N plays a renal-protective role, probably through antiapoptotic and antioxidant mechanisms. BA-N may regulate mitochondria pathway via decreasing Bax/Bcl-2 ratio, inhibiting caspase 3 expression and Cyt C release. Overall, BA-N may have potentials as an anti-AKI drug.

Double network (DN) hydrogels, a kind of promising soft and tough hydrogels, are produced by two unique contrasting networks with designed network entanglement burst into the field of materials science as versatile functional systems for a very broad range of applications. A part of the DN hydrogels is characterized by extraordinary mechanical properties providing efficient biocompatible and high strength for holding considerable promise in tissue engineering. Following DN hydrogels principles and consideration of biomedical applications, we provide an overall view of the present various DN hydrogels and look forward to the future of DN hydrogels for tissue engineering. In this review, the preparation methods, structure, properties, current situation, and challenges are mainly discussed for the purpose of tissue engineering. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement.

New targeted RGD peptides obtained by solid phase peptide synthesis (SPPS) were successfully screened by Molecular Operating Environment (MOE) and used for the building of the 6-O-carboxymethyl chitosan based carrier with an active target on the surface. CRGDYC-6-O-carboxymethyl chitosan based nanoparticles (NPs) loaded with doxorubicin hydrochloride (DOX) were successfully prepared by an ionic gelation method with the carrier synthesized before. Synthesis conditions and formulation parameters were optimized by determining the characteristics of nanoparticles including the particle size and drug encapsulation efficiency. 6-O-Carboxymethyl chitosan concentration, calcium chloride concentration and calcium chloride/6-O-carboxymethyl chitosan ratio all had effects on the particle size and drug encapsulation efficiency. Nanoparticles with an average diameter of 193.4 nm, an average drug loading efficiency of up to 69.5% and an average drug loading of up to 0.395% were prepared successfully with the optimal formulation. Flow cytometry and confocal microscopy analyses showed that the cellular uptake of DOX in human breast cancer cell lines (MCF-7) was higher in the CRGDYC-modified nanoparticles compared with the unmodified nanoparticles. In vivo imaging showed that the distribution of CRGDYC-modified nanoparticles in the tumor site was higher compared with the unmodified nanoparticles. These results suggest that CRGDYC-6-O-carboxymethyl chitosan may be a promising cancer targeting carrier which can enhance the intracellular uptake and cytotoxicity of the drug-loaded nanoparticles.

Peptide amphiphiles (PAs), functionalized with alkyl chains, are capable of self-assembling into various nanostructures. Recently, PAs have been considered as ideal drug carriers due to their good biocompatibility, specific biological functions, and hypotoxicity to normal cells and tissues. Meanwhile, the nanocarriers formed by PAs are able to achieve controlled drug release and enhanced cell uptake in response to the stimulus of the physiological environment or specific biological factors in the location of the lesion. However, the underlying detailed drug delivery mechanism, especially from the aspect of primary and secondary structures of PAs, has not been systematically summarized or discussed. Focusing on the relationship between the primary and secondary structures of PAs and stimuli-responsive drug delivery applications, this review highlights the recent advances, challenges, and opportunities of PA-based functional drug nanocarriers, and their potential pharmaceutical applications are discussed.

The development of hydrogels for bone regeneration has highlighted the challenge that load-bearing hydrogels need to be biocompatible while achieving high strength. Several approaches have been reported to improve the toughness of hydrogels, but achieving high toughness and biocompatibility simultaneously remains a challenge. Here we report a polyacrylic acid/alginate/demineralized bone matrix (PAA/Alg/DBM) hybrid double network hydrogel, which was synthesized by a two-step sequential polymerization with embedded DBM, possessing both high strength and biocompatibility. With the persistence of DBM, it can promote the synthesis of VEGF and bFGF and the ALP activity of MG63 cells on hydrogel. All the results suggest that this hybrid double network hydrogel have potential for future application in bone regeneration.

Bone tissue engineering uses the principles and methods of engineering and life sciences to study bone structure, function and growth mechanism for the purposes of repairing, maintaining and improving damaged bone tissue. Scaffolds not only provide structural support for stem cells in cell adhesion and proliferation and bone formation, but also serve as a microenvironment for guiding stem cell differentiation and tissue regeneration and for controlling tissue structure. This review presents the research status of the scaffold microenvironment for bone-related stem cells based on bone tissue engineering. Scaffold materials and the stem cell microenvironment are described in this review, and the existing shortcomings are also simply mentioned.