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Nitrogen-doped carbon submicrospheres (NCSMs) are synthesized via an efficient and environmentally friendly one-pot polymerization reaction at room temperature, in which dopamine hydrochloride serves as the source for both carbon and nitrogen. Through leverage of its distinctive structure characterized by minimal surface area, fewer oxygen-containing functional groups, and a heightened presence of active nitrogen-doping sites, the synthesized NCSM showcases a noteworthy initial Coulombic efficiency (ICE) of 84.8%, a remarkable sodium storage capacity of 384 mAh g-1, an impressive rate capability of 215 mAh g-1 at 10 A g-1, and a superior cyclic performance, maintaining 83.0% of its capacity after 2000 cycles. The submicron spherical structure, with its limited surface area and scarce oxygen-containing moieties, effectively curtails the irreversible sodium-ion loss in solid-electrolyte interphase film formation, resulting in heightened ICE. The abundant nitrogen doping can expand carbon-layer spacing as well as improve the electron/ion-transport dynamics, guaranteeing a high sodium storage capacity and a strong rate capability. Crucially, the synthesis method presented here is straightforward, effective, and amenable to scaling, offering a novel avenue for the commercialization of sodium-ion batteries.

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Manganese silicate (Mn2SiO4) possesses a more suitable volume expansion (186%) compared to SiOx-based materials and is also characterized by low cost, environmental friendliness, and considerable theoretical capacity. Hollow Mn2SiO4 sub-microspheres encapsulated by a highly continuous network of conductive carbon (MSC) are prepared by the self-templating method and subsequent ZIF-8-derived carbon coating. The as-prepared Mn2SiO4@C hybrid under optimal conditions (MSC-2) can provide a high capacity of 1343 mA h g-1 at 0.2 A g-1 and an excellent rate performance of 434 mA h g-1 at 10 A g-1. Even after 500 cycles, MSC-2 can still maintain a considerable specific capacity of 554 mA h g-1 at a high current density of 5.0 A g-1. Additionally, the full cell assembled with MSC-2 anode and LiFePO4 cathode (MSC-2//LFP) possesses a robust energy density of 218 W h kg-1, excellent power density of 2.5 kW kg-1, and good cycling stability.

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The development of high-performance carbon-based anode materials is still a significant challenge for K-ion storage. In our work, we designed reduced graphene oxide coating carbon sub-microspheres hierarchical nanostructure (CS@RGO) hierarchical nanostructure via a simple freeze-drying and subsequent pyrolysis as anode for K-ion batteries (KIBs), which presented an excellent electrochemical performance for K-ion storage, with a reversible specific capacity of 295 mAh g-1 after 100 cycles at 100 mAh g-1. Even at a high current density of 1 A g-1, our CS@RGO still achieves ultra-stable K-ion storage of 200 mAh g-1 at 1 A g-1 after 5000 cycles almost without capacity fade. According to the galvanostatic intermittent titration technique result, the CS@RGO hybrid receives a high average diffusion coefficient of 7.35 × 10-8 cm2 s-1, contributing to the rapid penetration of K-ion, which facilitates the enhancement of electrochemical performance for KIBs. Besides, we also use Raman spectra to investigate the electrochemical behavior of our CS@RGO hybrid for K-ion storage and confirm the reaction process. We believe that our work will offer the opportunity to enable ultra-stable carbon-based materials by the structure design in the K-ion battery field.

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Albumin nanoparticles represent an approved anti-tumor drug delivery system. However, there is only one albumin nanoparticle product (paclitaxel-albumin nanoparticle) on the market. The application of albumin carriers is limited by the lack of universal preparation technology and insufficient targeting effect. Herein, we developed multifunctional albumin sub-microspheres prepared by coaxial-electrospray technology to co-delivery bufalin and nintedanib for tumor-targeted combination therapy. The biguanide and ursodeoxycholic acid dual-modified multifunctional albumin was synthesized to enhance the anti-tumor effect and tumor target efficiency. Coaxial-electrospray technology was utilized in preparing albumin sub-microspheres with a core-shell structure that enables payload efficiency and stability. More importantly, the in vitro and in vivo experiments demonstrated that the multifunctional albumin sub-microspheres possessed superior tumor target efficiency. Furthermore, nintedanib and bufalin combined therapy relieved the tumor microenvironment and exerted a synergistic therapeutic effect. Therefore, this work provides a novel method for fabricating an albumin-based drug delivery system and a potential efficient combination therapeutic strategy for tumor treatment.

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Sodium-ion batteries (SIBs) are the appropriate alternatives to lithium-ion batteries (LIBs) for the large-scale energy storage applications because of the abundant resources and wide distribution of sodium on earth. O3-NaCrO2 is a promising cathode material for SIBs due to its stable structure and low-cost raw materials. In this paper, we design and synthesize a powder consisting of submicrometer-sized O3-NaCrO2 spheres (s-NaCrO2) self-assembled with nanoflakes, which exhibits faster ion migration ability and strong structure robustness. The galvanostatic intermittent titration technique test reveals the higher apparent Na+ diffusion coefficient of s-NaCrO2 when compared with a normal NaCrO2 powder with an irregular particle morphology. The s-NaCrO2 shows impressive electrochemical properties with a capacity of 90 mAh g-1 at 50 C. In addition, outstanding cycling stability is shown when tested at 20 C, where a capacity of 90 mAh g-1 is maintained with a retention of 87% after 1500 cycles. Also, s-NaCrO2 is advantageous at high (50 °C) and low (-10 °C) temperatures. The full cells assembled employing Sb/C as the anode exhibit good rate capability with 85 mAh g-1 obtained at 50 C.

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In the traditional Fenton process, the efficient generation of hydroxyl radical (HO) strongly relies on an acidic circumstance and the iron ions would precipitate and form large amounts of hazardous iron-containing sludge at alkaline pH. To realize stable heterogeneous Fenton-like catalytic degradation at alkaline condition, Fe3O4 submicrospheres with SiO2 coating were successfully synthesized by using water glass as the silica sources via a facile ultrasound assisted method. The as-obtained Fe3O4@SiO2 spheres were further used as catalysts for the Fenton-like degradation of tetracycline hydrochloride (TC). The Fe3O4@SiO2 submicrospheres exhibited superior catalytic activity in higher pH environment (pH value = 11), and the degradation efficiency toward TC was ca. 80% after ten successive runs. The kinetics for the catalytic degradation of TC were agreed well with the second-order kinetic model. The reaction rate constant (k) over the Fe3O4@SiO2 submicrospheres at a pH value of 11 was 7.69 times greater than that at a pH value of 3. Reactive species scavenging experiments revealed that HO and superoxide radical (O2- / HO2-) played a dominant role during the Fenton-like degradation of TC at pH 3 and pH 11, respectively. Possible Fenton-like degradation pathways of TC were proposed through the identification of intermediates using the high performance liquid chromatography coupled with mass spectrometry (HPLC-MS), which involved cleavage of methyl groups, N-dimethyl group, and hydroxy groups, ring-opening reaction, etc. The degradation efficiency of TC was close to 91.5% and total organic carbon (TOC) in solution was eliminated by about 41.4% at the optimized conditions. In a word, with the unique acidic surface properties and abundant Si-OH bonds, the Fe3O4@SiO2 submicrospheres exhibited well dispersion, good catalytic activity, strong alkali resistance and excellent recyclability in an ultrasonic-Fenton-like system.

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Clostridium difficile colitis is caused by a cytotoxin produced by the anaerobic bacteria C. difficile in the epithelial cells of the large intestine, particularly C. difficile toxin B (TcdB). However, the sensitivity of currently utilized C. difficile endotoxin determination methods has been called into question, and, therefore, more accurate and convenient detection methods are needed. Our study is the first to systematically compare fluorescent submicrosphere-based and quantum-dot nanobead-based lateral fluidity measurement methods (FMs-LFA and QDNBs-LFA) with toxin B quantification in fecal samples via sandwich analysis. The limits of detection (LOD) of FMs-LFA and QDNBs-LFA in the fecal samples were 0.483 and 0.297 ng/mL, respectively. TcdB analyses of the fecal samples indicated that the results of QDNBs-LFA and FMs-LFA were consistent with those of a commercial enzyme-linked immunosorbent assay (ELISA) test kit. The sensitivity of QDNBs-LFA was highly correlated with clinical diagnoses. Therefore, quantum dot nanobeads (QDNBs) are deemed highly suitable for lateral fluidity analyses, which would facilitate the implementation of portable and rapid on-the-spot applications, such as food hygiene and safety tests and onsite medical testing.

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Calcium phosphate (CaP)-based submicrospheres containing magnetic iron oxide (IO) nanoparticles (IO-CaP submicrospheres) have potential for various biomedical applications. We recently achieved facile one-pot fabrication of IO-CaP submicrospheres using a laser-assisted precipitation process in which weak pulsed laser irradiation was applied to a labile CaP reaction mixture supplemented with ferrous ions under adequate pH. In this study, we performed cross-sectional transmission electron microscopy (TEM) analysis of the resulting IO-CaP submicrospheres. The cross-sectional TEM analysis revealed that the IO-CaP submicrospheres were heterogeneous in their internal nanostructures and could be categorized into two types, namely types A and B. The type A submicrospheres contained single nano-sized IO nanoparticles homogeneously dispersed throughout the CaP-based matrix. The type B submicrospheres contained larger IO nanoparticles with an irregular or spherical shape, which were mostly a few tens of nanometers in size along with one or two submicron-sized domains. These findings provide new insight into the formation mechanism of IO-CaP submicrospheres in this fabrication technique as well as future applications of the resulting IO-CaP submicrospheres.

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Recently, rock-salt NiCoO2 (NCO) with desirable electronic conductivity has drawn enormous interest worldwide for energy-related applications. However, the intrinsically sluggish kinetics and electrode aggregation/volumetric change/pulverization during Li-insertion/-extraction processes hugely limit its applications in Li-ion batteries (LIBs). In the contribution, we first devise a bottom-up method for scalable fabrication of the nanodimensional NCO particles encapsulated in porous nitrogen-doped carbon submicrospheres (NCS), which are derived from a bimetal (Ni, Co) metal-organic framework. The porous NCS, as a flexible conductive skeleton, can buffer distinct volume expansion as an efficient buffering phase, restrain agglomeration of nanoscaled NCO, and enhance electronic conductivity and wettability of the electrode. Benefiting from the synergistic functions between the nanodimensional NCO and porous NCS, the obtained NCO@NCS anode (∼74.5 wt % NCO) is endowed with remarkable high-rate reversible capacity (∼403.0 mAh g-1 at 1.0 A g-1) and cycling behaviors (∼371.4 mAh g-1 after being cycled for 1000 times at 1.0 A g-1) along with a high lithium diffusion coefficient and remarkable pseudocapacitive contribution. Furthermore, the NCO@NCS-based full LIBs exhibit competitive lithium-storage properties in terms of energy density (∼217.0 Wh kg-1) and cyclic stability. Furthermore, we believe that the methodology is highly promising in versatile design and construction of binary metal oxide/carbon hybrid anodes for advanced LIBs.

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Polydopamine-modified additives have been thus far widely used in the mixed matrix membranes (MMMs) for gas separation. However, very few reports focus on the polydopamine alone and investigate its contribution to the gas separation performance. Herein, the polydopamine-derived submicrospheres (PDASS) were paired with polymers of intrinsic microporosity (PIM-1) to fabricate high-performance gas separation membranes, through which the effects of PDASS on gas permeability and CO2/N2 separation performance were systematically investigated. The addition of PDASS provides a 1.6-fold enhancement in CO2/N2 selectivity together with acceptable gas permeability as compared to the original polymeric membrane. Such enhanced separation behavior is supposed to stem from the densified membrane microstructure induced by the strong intermolecular interactions between PIM-1 and PDASS (i.e., charge transfer, π-π stacking, and hydrogen bonding). Importantly, the physical aging behavior, as judged by gas permeability, is retarded for PIM/PDASS membranes after 4 months of testing.

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Developing cheap, abundant, and easily available electrocatalysts to drive the hydrogen evolution reaction (HER) at small overpotentials is an urgent demand of hydrogen production from water splitting. Molybdenum disulfide (MoS2 ) based composites have emerged as competitive electrocatalysts for HER in recent years. Herein, nickel@nitrogen-doped carbon@MoS2 nanosheets (Ni@NC@MoS2 ) hybrid sub-microspheres are presented as HER catalyst. MoS2 nanosheets with expanded interlayer spacings are vertically grown on nickel@nitrogen-doped carbon (Ni@NC) substrate to form Ni@NC@MoS2 hierarchical sub-microspheres by a simple hydrothermal process. The formed Ni@NC@MoS2 composites display excellent electrocatalytic activity for HER with an onset overpotential of 18 mV, a low overpotential of 82 mV at 10 mA cm-2 , a small Tafel slope of 47.5 mV dec-1 , and high durability in 0.5 H2 SO4 solution. The outstanding HER performance of the Ni@NC@MoS2 catalyst can be ascribed to the synergistic effect of dense catalytic sites on MoS2 nanosheets with exposed edges and expanded interlayer spacings, and the rapid electron transfer from Ni@NC substrate to MoS2 nanosheets. The excellent Ni@NC@MoS2 electrocatalyst promises potential application in practical hydrogen production, and the strategy reported here can also be extended to grow MoS2 on other nitrogen-doped carbon encapsulated metal species for various applications.

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A hybrid based on nickel phosphide nanoparticle assembled submicrospheres coated with a glucose-derived carbon shell is synthesized from Ni-glycerate precursors through a carbon coating route and a subsequent calcination-phosphatization approach. Characterization results indicate that the synthesized submicrospheres have a diameter of ∼500 nm and are composed of nanoparticles as subunits with sizes ranging from 30 to 40 nm. Each sphere and its subunits are coated by a continuous carbon coating shell. The electrochemical performance of the material as an anode for reversible energy storage is investigated and evaluated. A comparative study of the lithium/sodium storage properties between the hybrid and pure nickel phosphide is carried out. The electrochemical results demonstrate that the hybrid fabricated electrode is a highly attractive anode for lithium- and sodium-ion batteries, exhibiting much better lithium/sodium storage properties compared to the nickel phosphide submicrospheres of the same construction. The reasons for the enhanced energy storage performance of the submicrospheres are explored by a series of comparison experiments based on morphology, structure, electrical conductivity, and kinetic property.

RESUMEN

Label selection is a critical factor for improving the sensitivity of lateral flow assay. Time-resolved fluorescent nanobeads, fluorescent submicrospheres, quantum dots, and colloidal gold-based lateral flow assay (TRFN-LFA, FM-LFA, QD-LFA, and CG-LFA) were first systematically compared for the quantitative detection of ractopamine in swine urine based on competitive format. The limits of detection (LOD) of TRFN-LFA, FM-LFA, QD-LFA, and CG-LFA were 7.2, 14.7, 23.6, and 40.1pg/mL in swine urine samples, respectively. The sensitivity of TRFN-LFA was highest. In the quantitative determination of ractopamine (RAC) in swine urine samples, TRFN-LFA exhibited a wide linear range of 5pg/mL to 2500pg/mL with a reliable coefficient of correlation (R2=0.9803). Relatively narrow linear ranges of 10-500pg/mL (FM-LFA) and 25-2500pg/mL (QD-LFA and CG-LFA) were acquired. Approximately 0.005µg of anti-RAC poly antibody (pAb) was used in each TRFN-LFA test strip, whereas 0.02, 0.054, and 0.15µg of pAb were used in each of the FM-LFA, QD-LFA, and CG-LFA test strips, respectively. In addition, TRFN-LFA required the least RAC-BSA antigens and exhibited the shortest detection time compared with the other lateral flow assays. Analysis of the RAC in swine urine samples showed that the result of TRFN-LFA was consistent with that of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a commercial enzyme-linked immunosorbent assay (ELISA) kit.

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We achieved rapid, surfactant-free, and one-pot fabrication of antibacterial calcium phosphate (CaP) submicrospheres containing silver nanoparticles by combining physical laser and chemical coprecipitation processes. In this physicochemical process, weak pulsed laser irradiation (20min) was performed on a labile CaP reaction mixture supplemented with silver ions as a light-absorbing agent. The silver content in the submicrospheres was controlled for a wide range (Ag/P elemental ratio varied from 0.60 to 62.0) by tuning the initial concentration of silver ions (from 5 to 20mM) in the CaP reaction mixture. At the silver concentration of 5mM, we obtained unique nanocomposite particles: CaP submicrospheres (average diameter of approximately 500nm) containing metallic silver nanoparticles dispersed throughout, as a result of CaP and silver coprecipitation with simultaneous photoreduction of silver ions and spheroidization of the coprecipitates. These CaP submicrospheres containing silver nanoparticles (ca. 0.3mg silver per 1mg submicrospheres) exhibited antibacterial activity against major pathogenic oral bacteria, i.e., Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Moreover, the CaP submicrospheres dissolved and neutralized the acidic environment generated by Streptococcus mutans, demonstrating their potential as acid-neutralizing and remineralizing agents. The present process and resulting antibacterial CaP-based submicrospheres are expected to be useful in dental healthcare and infection control. STATEMENT OF SIGNIFICANCE: Nano- and microsized spheres of calcium phosphate (CaP) containing silver nanoparticles have great potential in dental applications. Conventional fabrication processes were time-consuming or weak regarding the size/shape control of the spheres. In this study, we achieved a simple (one-pot), rapid (20-min irradiation), and surfactant-free fabrication of CaP submicrospheres containing silver nanoparticles by pulsed laser irradiation to a mixture of calcium, phosphate, and silver ion solutions. The resulting CaP submicrospheres contained metallic silver nanoparticles dispersed throughout in a sequence of reactions: CaP and silver coprecipitation, laser-induced melting and spheroidization of the coprecipitates, and photoreduction of silver ions. These submicrospheres showed antibacterial activity against oral bacteria and acid-neutralizing property in the bacterial suspension, and hence are worth considering for dental applications.

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TiO2 sub-microspheres composed of anatase granular-like nanocrystallines with an average diameter ∼250 nm are synthesized using sol-gel method and employed as the scaffold layer for efficient mesocopic perovskite solar cells. Compared with mesoporous TiO2 films composed of ∼18 nm nanoparticles, the sub-microsphere films show superior light-trapping characteristics and significantly improve the light-harvesting capability of the solar cells. In addition, the charge-transport performance is also dramatically improved according to the transient photocurrent decay despite there being no significant difference in the perovskite layer surface morphology. As a result, an average power conversion efficiency of 15% with a highly uniform distribution is achieved for the solar cells with TiO2 sub-microsphere films, 12% higher than those with TiO2 nanoparticle films. The combination of light-harvesting capability and fast charge transfer make the TiO2 sub-microsphere film a good candidate as the scaffold layer for efficient perovskite solar cells.

RESUMEN

In general, the properties and performance of mesoporous TiO2 are greatly dependent on its crystal size, crystallinity, porosity, surface area, and morphology; in this regard, design and fine-tuning the crystal and pore sizes of the TiO2 submicrospheres and investigating the effect of these factors on the properties and photoelectric performance of dye-sensitized solar cells (DSSCs) is essential. In this work, uniform TiO2 submicrospheres were synthesized by a two-step procedure containing hydrolysis and solvothermal process. The crystal and pore sizes of the TiO2 submicrospheres were fine-tuned and controlled in a narrow range by adjusting the quantity of NH4OH during the solvothermal process. The effect of crystal and pore size of TiO2 submicrosphere on the performance of the DSSCs and their properties including dye-loading capacity, light scattering effect, power conversion efficiency (PCE), incident photon-to-electron conversion efficiencies (IPCEs), and electron recombination were compared and analyzed. The results show that increasing pore size plays a more significant role in improving the dye-loading capacity and PCE than increasing surface area, and an overall PCE value of 8.62% was obtained for the device with a 7.0 µm film thickness based on the TiO2 submicrospheres treated with 0.6 mL of NH4OH. Finally, the best TiO2 submicrosphere based photoanode film was optimized by TiCl4 treatment, and increasing film thickness and a remarkable PCE up to 11.11% were achieved.

RESUMEN

A novel method was developed to synthesize organic-inorganic hybrid hollow sub-microspheres (HHSs) through the addition of colloidal SiO2. The hydrolysis rate of 3-(methacryloyloxy)propyltrimethoxysilane (MPS) was accelerated by SiO2 particles; meanwhile, the condensation rate of the hydrolytic species was decelerated. Thus, the hydrolytic monomers and oligomers of MPS were preserved as emulsifiers. These emulsifiers can then emulsify the isopentyl acetate (PEA) to form a steady O/W emulsion. The HHSs were produced by subsequent free radical polymerization and removal of the oil core. The hydrolytic MPS acted as emulsifiers and polymerizable monomers at the emulsification and polymerization stage, respectively. Thus, extra emulsifiers, co-emulsifiers, and organic monomers were omitted, which simplified the synthesis process. The good dispersion of HHSs in water and oil, as well as the EDX results, indicated the organic-inorganic hybrid structure of HHSs.

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