Good Monodispersity Research Articles

3D simulation estimation and experimental validation of droplet generation in CFD-based flow-focusing microfluidic chips

Abstract Microdroplets generated using microfluidic techniques offer significant advantages over those generated using conventional methods, including high accuracy and excellent monodispersity. However, there remains a paucity of literature regarding the influence of fluid operating conditions and physical properties on droplet generation, specifically in relation to size and frequency, using computational fluid dynamics (CFD) techniques. In this study, we present a simplified microfluidic chip capable of flexibly adjusting the structure and size of the microchannels based on specific requirements. Subsequently, three-dimensional numerical simulations of this chip were conducted using CFD techniques and fitted a dimensionless model to estimate the droplet generation size and frequency through multivariate nonlinear regression methods. The experimental validation results demonstrated a strong correlation between the fitted data and the experimental observations, with size differences not exceeding 8% and good monodispersity, indicated by a coefficient of variation of less than 2.4%. This study provides valuable insights and a reference for future research.

Enhanced control and efficiency in millimeter-scale composite droplets preparation

A microfluidic device utilising the flow focusing method was designed and fabricated for the high-throughput and controllable preparation of millimeter-scale water-in-oil (W1/O/W2) droplets. Two distinct flow focusing modes were employed in order to prepare the composite droplets. In the flow-focused axisymmetric jetting mode, the continuous phase propels the dispersed phase, forming a cone, which subsequently leads to a jet formation downstream of the small hole. When the outer phase is activated, perturbation growth interferes with downstream fragmentation, resulting in composite droplets with excellent monodispersity. In the dripping mode, the dispersed phase fails to form a jet downstream, and the interface disintegrates, resulting in droplet formation at the exit of the small orifice. In the jetting mode, the size and shell-to-core ratio of the generated droplets can be controlled by adjusting the volume of flow of the outer and inner phases, as well as the applied frequency. Furthermore, the applied perturbation allows for precise control of droplet size, which significantly reduces satellite droplet formation and enhances droplet monodispersity. In the dripping mode, the shell-to-core ratio is adjusted by manipulating the ratio of inner to outer flow rates, which is tailored to the specific requirements of the flow-focused dripping mode. The prepared compound droplets exhibit good monodispersity. Finally, the rotational solidification method can be employed to obtain spherical shells with a shell thickness of less than 20 μm. In conclusion, the flow focusing method is an effective, controllable, and stable method for synthesising millimetre-sized composite droplets.

Design of Delivery Systems (Nanoemulsions and Biopolymer Nanoparticles) of Cloves Essential Oil: Preparation, Characterizations, Study the Release, and Antioxidant Activity

Abstract BACKGROUND: Clove oil has a wide range of therapeutic and pharmaceutical applications. It is also used in the manufacture of pesticides and antifungals, as well as many advantages. The study aims to improve the properties of essential oils, especially clove oil, and make them more stable by the design of delivery systems (nanoemulsions and biopolymer nanoparticles). METHODS: Clove oil was mixed with water in the presence of tween-20 as a polysorbate-type nonionic surfactant, and then carboxymethyl cellulose was added with different ratios of glycerin as a cross-linking agent. The formation of the clove nanogel was tested by spectrophotometric assay 2.2.2 Fourier transform infrared spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), dynamic light scattering (DLS), and morphology method field emission scanning electron microscopy (FESEM), also the rate of clove oil release during different periods, and hemolytic and antioxidant activity were tested. RESULTS: The nanoparticles were demonstrated by DLS and FESEM. The polydispersity index value was 0.279, indicating good monodispersity and good stability, while higher release values were obtained when glycerol was not present as a cross-linker. In addition to the higher antioxidant, values of the clove oil nano emulsion (CNE) have a maximum inhibition of 65% at a concentration of 100 μg/mL, whereas clove nano-gel (CNG) at the same concentration exhibited 59.2% inhibition. The calculated IC50 values of CNG and CNE were 6.58 and 3.25 μg/mL, respectively. CONCLUSION: The study proved through the results obtained that nanocomposites help stabilize components, especially volatile oil, which increases their effectiveness.

IL-1ra loaded chondroitin sulfate-functionalized microspheres for minimally invasive treatment of intervertebral disc degeneration

Presently, the clinical treatment of intervertebral disc degeneration (IVDD) remains challenging, but the strategy of simultaneously overcoming the overactive inflammation and restoring the anabolic/catabolic balance of the extracellular matrix (ECM) in the nucleus pulposus (NP) has become an effective way to alleviate IVDD. IL-1ra, a natural antagonist against IL-1β, can mitigate inflammation and promote regeneration in IVDD. Chondroitin sulfate (CS), an important component of the NP, can promote ECM synthesis and delay IVDD. Thus, these were chosen and integrated into functionalized microspheres to achieve their synergistic effects. First, CS-functionalized microspheres (GelMA-CS) with porous microstructure, good monodispersion, and about 200 µm diameter were efficiently and productively fabricated using microfluidic technology. After lyophilization, the microspheres with good local injection and tissue retention served as the loading platform for IL-1ra and achieved sustained release. In in vitro experiments, the IL-1ra-loaded microspheres exhibited good cytocompatibility and efficacy in inhibiting the inflammatory response of NP cells induced by lipopolysaccharide (LPS) and promoting the secretion of ECM. In in vivo experiments, the microspheres showed good histocompatibility, and local, minimally invasive injection of the IL-1ra-loaded microspheres could reduce inflammation, maintain the height of the intervertebral disc (IVD) and the water content of NP close to about 70 % in the sham group, and retain the integrated IVD structure. In summary, the GelMA-CS microspheres served as an effective loading platform for IL-1ra, eliminated inflammation through the controlled release of IL-1ra, and promoted ECM synthesis via CS to delay IVDD, thereby providing a promising intervention strategy for IVDD. Statement of significanceThe strategy of simultaneously overcoming the overactive inflammation and restoring the anabolic/catabolic balance of the extracellular matrix (ECM) in nucleus pulposus (NP) has shown great potential prospects for alleviating intervertebral disc degeneration (IVDD). From the perspective of clinical translation, this study developed chondroitin sulfate functionalized microspheres to act as the effective delivery platform of IL-1ra, a natural antagonist of interleukin-1β. The IL-1ra loading microspheres (GelMA-CS-IL-1ra) showed good biocompatibility, good injection with tissue retention, and synergistic effects of inhibiting the inflammatory response induced by lipopolysaccharide and promoting the secretion of ECM in NPCs. In vivo, they also showed the beneficial effect of reducing the inflammatory response, maintaining the height of the intervertebral disc and the water content of the NP, and preserving the integrity of the intervertebral disc structure after only one injection. All demonstrated that the GelMA-CS-IL-1ra microspheres would have great promise for the minimally invasive treatment of IVDD.

Design of ZnS nanospheres antireflective structure for mid and far infrared applications

Developing high-performance mid and far infrared antireflection films is a significant requirement in the field of infrared optics. This study successfully prepared AR films composed of ZnS nanospheres for mid and far infrared bands using a combination of hydrothermal and sol-gel methods. Initially, ZnS nanospheres with uniform size and good monodispersity were synthesized via the hydrothermal method and subsequently coated on CdSe substrate through dip coating. The refractive index of the ZnS film is adjusted between 1.36 and 1.52. A significant AR effect was observed in ZnS nanospheres film on CdSe substrate at 3–5 μm and 8–14 μm, and the reflectance is approximately 3 % which is about 25 % lower than that of the uncoated sample. Upon coating with a TiO2 protective layer, the reflectivity further decreased to about 0.6 % and the film demonstrated excellent weather resistance and mechanical properties. This work provides a novel approach for the preparation and regulation of mid and far infrared AR film, significantly contributing to the development of optical film.

Rapid Microwave Method to Enhance the Characteristics of Fe3O4 and Fe3O4/SiO2 Nanoparticles

The application of nanoparticles can increase the number of products and protect against the deadly effects of industrial processes. Generally, nanoparticle technology offers numerous benefits, including reduced energy consumption and waste generation. Therefore, this study aimed to prepare Fe3O4 and Fe3O4/SiO2 nanoparticles using rapid microwave method. The instruments used for analysis included x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscopy-dispersive x-ray (SEM-EDX), and ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS). The combustion process was carried out using a microwave to produce sufficient energy for forming Fe3O4 nanoparticles. The homogeneous heating distribution process in the raw material effectively formed different initial phases and nanoparticle morphologies within a few minutes. The results showed that the application of rapid and efficient microwave provided good monodispersity, uniform core-shell structure, and high magnetization. The calculated optical bandgap values for Fe3O4 and Fe3O4/SiO2 ranged from 1.77–2.33 eV. According to magnetic analysis, Fe3O4 nanoparticles showed superparamagnetic behavior at room temperature with a value of 32–40 emu/g, while Fe3O4/SiO2 powder had 9–23 emu/g. The analysis of SEM-EDX showed that SiO2 had the potential to prevent particle aggregation and stabilize the nanoparticles prepared. Moreover, further study is recommended to modify the product with other materials, such as TiO2, for photocatalysts.

Laser-Induced Graphene/h-BN Laminated Structure to Enhance the Self-Lubricating Property of Si3N4 Composite Ceramic

Incorporating graphene as ceramic additives can significantly enhance both the toughness and self-lubricating characteristics of ceramic matrices. However, due to the difficult dispersion and easy agglomeration of graphene, the preparation process of composite ceramics still faces many problems. In this study, a laminated laser-induced reduced graphene oxide/hexagonal boron nitride (L-rGO/h-BN) was introduced as an additive into a silicon nitride matrix, then a silicon nitride/reduced graphene oxide/hexagonal boron nitride (Si3N4/L-rGO/h-BN) ceramic composite was successfully synthesized using Spark Plasma Sintering technology. This approach led to enhancements in both the mechanical and self-lubricating properties of silicon nitride ceramics. This is due to the good monodispersity of the incorporating graphene in the silicon nitride matrix. The flexural strength and fracture toughness of the ceramic composite experienced notable increases of 30.4% and 34.4%, respectively. Tribological experiments demonstrate a significant enhancement in the self-lubricating performance of ceramic composites upon the incorporation of L-rGO/h-BN. The coefficient of friction and wear spot diameter experienced reductions of 26.6% and 21%, respectively. These improvements extend the potential industrial applications of Si3N4/L-rGO/h-BN ceramic composites. Throughout the friction process, the evenly exposed rGO and h-BN demonstrate an effective self-lubricating effect on the wear surface. This research paves the way for a novel approach to fabricating high-performance self-lubricating structural ceramics.

Chiral resolution of ketoprofen by modified polymethyl methacrylate microspheres

AbstractDue to unique structural characteristics and chiral environment, β‐cyclodextrin (β‐CD) has a strong chiral separation ability. 4‐Chlorophenyl isocyanate (4CPI) also plays an important role in separating chiral drugs. In this paper, a chiral stationary phase: 4‐CPI‐β‐CD stationary phase (4CPI‐β‐CD@PMMA) was designed and prepared. Polymethyl methacrylate (PMMA) microspheres with uniform particle size and good monodispersity were prepared by modified seed polymerization and seed expansion methods. Using diazo resin as a coupling agent, PMMA microspheres were connected with 4CPI‐β‐CD to prepare a stationary phase with chiral recognition ability. PMMA microspheres and 4CPI‐β‐CD were also characterized. Compared with the traditional silica gel column, PMMA microspheres have higher preparation efficiency, better monodispersity, and better mechanical properties as chromatographic fillers. Finally, the chiral separation of ketoprofen was carried out by reversed‐phase high‐performance liquid chromatography, and the separation conditions were optimized. This paper is a good idea for the preparation of the chiral stationary phase.

Zwitterionic targeting nanodrugs prepared from poly(propyleneimine) dendrimers for enhanced anti-tumor therapy

Development of targeting and high drug loading drug delivery system has been gaining great interest. Zwitterionic modification of the terminal amine groups on G2 poly(propyleneimine) (G2 PPI) dendrimers was achieved via the thiol-ene click reaction, followed by the introduction of the anti-cancer drug paclitaxel and targeting peptides c(RGDfC), then the micelles were formed through self-assembly behavior, subsequently doxorubicin was encapsulated internally, finally the targeting drug-loaded micelles PPIMPRC-DOX were synthesized. The PPIMPRC-DOX micelles were irregular spherical with good monodispersity. The average particle size from TEM image was 63.05 nm and the hydrodynamic size was 93.1 nm, both of which were relatively uniform. The critical micelle concentration was 48.52 μg/mL, the total drug loading efficiency was 32.45 %. In vitro release experiments revealed that within the mildly acidic environment of tumors, PPIMPRC-DOX micelles exhibited enhanced release efficiency and increased accumulation of DOX. The anti-nonspecific protein adsorption experiment proved that the interaction between the PPIMPRC-DOX micelles and fibrinogen was very weak, and they had good anti-nonspecific protein adsorption ability. The cytotoxicity assessments using the MTT assay on HeLa cells and A549 cells revealed obvious cytotoxic effects of PPIMPRC-DOX micelles on both cells. Hence, the utilization of zwitterionic G2 PPI dendrimers in constructing PPIMPRC-DOX micelles holds promise as a prospective nanodrug delivery system.

Optimal conditions for nano-emulsified vegetable oil synthesis for the biostimulation of 1,1,2-trichloroethane and vinyl chloride contaminated groundwater in bioreactors

Contamination of groundwater with chlorinated aliphatic hydrocarbons (CAHs) has become increasingly widespread. Enhanced reductive dechlorination (ERD) by emulsified vegetable oil (EVO) is an environmentally friendly, low-carbon and sustainable technology that effectively eliminates the threat from CAHs. To improve the permeability and bioavailability of EVO in the low-permeability substratum, nano-emulsified vegetable oil (nanoEVO) can be synthesized using a modified phase inversion composition method (MPIC) by increasing the emulsification temperature that reduces the shear force required for the formation of nanodroplets and the interfacial tension between the mixed phase and water. The emulsification temperature of 60 °C, the water content of 40–70%, the droplet diameter (DD) of nanoEVO prepared by MPIC is ∼200 nm, and had good monodispersion (≤0.2). The high molecular weight and low solubility of vegetable oil, and similar size of droplet make nanoEVO remains homogeneous after storage for > one year. NanoEVO can effectively biostimulate indigenous bacteria in CAHs-contaminated groundwater to dechlorinate 1,1,2-trichloroethane (1,1,2-TCA) to ethene via vinyl chloride (VC). The maximum dihaloelimination rate of 1,1,2-TCA was ∼66.06 μM·Cl−·day−1 and the maximum hydrogenolysis rate of VC was ∼35.67 μM·Cl−·day−1. NanoEVO effectively increased the relative abundance of Dehalococcoides from <0.10 to 9.61%. The abundances of Dhc 16S rRNA gene and dehalogenase gene vcrA increased by 102 and 103, respectively. Biostimulation shaped the structure of microbial communities and promoted hydrolytic acidification and anaerobic fermentation. Moreover, the syntrophic VFA-oxidizing bacteria participated in secondary fermentation and were closely correlated with H2 consumption metabolism. By providing carbon sources and maintaining an anaerobic environment with stable pH and ORP, nanoEVO biostimulated the hydrolytic acidification led by fermentative bacteria, secondary fermentation with syntrophic VFA-oxidizing bacteria and reductive dechlorination carried out by dechlorinator, thus greatly increasing the CAH-dechlorinating ability of indigenous microbial communities.

Preparation and evaluation of microcapsules of sodium alginate based on microfluidic technology

Many active ingredients in food products are destroyed by gastric acids and enzymes as they pass through the stomach, thereby reducing the desired effect of the target ingredient. In addition, traditional microcapsule preparation methods usually break up the dispersion by mechanical stirring or oscillation, which generates droplets of uneven size and inconsistent inclusion content, and mechanical external forces may cause denaturation and inactivation of active substances. This study aimed to use microfluidics to generate Oil-in-water-in-oil (O/W/O) droplet structures with good monodispersity and highly tunable properties, and to further prepare microcapsules with high encapsulation rate and targeted intestinal release by taking advantage of the cross-linking properties of alginate that reacts with Ca2+ under acidic conditions. Finally, the particle size distribution, release effect, encapsulation effect and oxidative stability of the core-shell microcapsules were evaluated. In this study, two types of microcapsules, homogeneous and core-shell microcapsules, were prepared by selecting tea polyphenols and vitamin E as models for hydrophilic and lipophilic bioactive compounds, respectively. Thin shell microcapsules with a shell thickness of about 25 μm were prepared using PDMS chip conditioning. Large microcapsules with a particle size of 230 μm were generated by using capillary glass tube chips, which had an excellent antioxidant property with a retention rate of 88.66 ± 1.25% of VE after 20 days of storage at 4 °C, while all of the VE was oxidized in the bare environment. In addition, in simulated gastric fluid, the release of VE was only about 20%, while in artificial intestinal fluid, the release was close to 100%, so the microcapsules also had intestinal targeting properties.

Selenium Nanoparticle Activity against S. mutans Biofilms as a Potential Treatment Alternative for Periodontitis.

The disruption of periodontal biofilms and prevailing antimicrobial resistance issues continue to pose a great challenge to the treatment of periodontitis. Here, we report on selenium nanoparticles (SeNPs) as a treatment alternative for periodontitis by determining their antibiofilm activity against S. mutans biofilms and the potential role of particle size in disrupting biofilms. SeNPs were synthesised via a reduction reaction. Various physicochemical characterisations were conducted on the NPs, including size and shape. The microbroth dilution method was used to conduct the biofilm and antibiofilm assay against S. mutans, which was analysed by absorbance. SeNPs displayed hydrodynamic sizes as low as 46 ± 4 nm at a volume ratio of 1:5 (sodium selenite/ascorbic acid) with good monodispersity and stability. Hydrodynamic sizes of SeNPs after resuspension in tryptic soy broth supplemented with 2.5% sucrose (TSB + 2.5% suc.) and incubated at 37 °C for 24 h, ranged from 112 to 263 nm, while the zeta potential values increased to greater than -11 mV. The biofilm assay indicated that S. mutans are weakly adherent, bordering on moderately adherent biofilm producers. The minimum biofilm inhibitory concentration (MBIC) was identified at 500 µg/mL. At a 1000 µg/mL concentration, SeNPs were able to inhibit S. mutan biofilms up to 99.87 ± 2.41% at a volume ratio of 1:1. No correlation was found between antibiofilm activity and particle size; however, antibiofilm activity was proven to be concentration-dependant. SeNPs demonstrate antibiofilm activity and may be useful for further development in treating periodontitis.

Preparation of TiO2/Ni‐NG Mesoporous Microspheres and Photocatalytic Hydrogen Evolution Properties

AbstractThe regulation of surface active sites and structures is a key factor affecting the performance of photocatalysts. In order to prepare monodisperse anatase TiO2 mesoporous microspheres with higher specific surface area, smaller pore size and particle size, a dual‐surfactant orientation assembly method was selected. Graphene (NG) was selected as a cocatalyst to compound with mesoporous TiO2 and nickel doping was performed on the cocatalyst to improve the photocatalytic hydrogen production activity of the semiconductor photocatalyst. Through proper regulation and rational design, the semiconductor photocatalyst with desired properties was prepared. SEM characterization of mesoporous titanium dioxide (TiO2/Ni‐NG) with graphene cocatalyst proved that TiO2 nanospheres have good monodispersion, and TiO2 nanospheres are well supported on graphene cocatalyst. The composite material belonged to mesoporous group with the pore size being mainly distributed between 10–20 nm. The loading of graphene and Ni‐NG cocatalyst increased the absorption band edge by 9 nm and 38 nm, respectively, and the band gap decreased by 0.07 eV and 0.16 eV, respectively. The selection of graphene as cocatalyst improved the hydrogen production activity of photocatalyst and nickel doping was very effective in the modification of graphene. For reaction time of 2.5 h, the H2 production of TiO2/Ni‐NG material reached 1.767 mmol/g which was 7.27 times that of TiO2/NG composite material.

Enhanced stability and confinement effects of Cs4PbBr6 quantum dots via mechanochemical immobilization on MOF nodes

Mechanochemical has emerged as an eco-friendly, efficient, and upscalable tool for the synthesis of perovskite quantum dots (PQDs). However, achieving control over the size and ensuring good mono-dispersion of PQDs by mechanochemistry, while simultaneously increasing their stability remains a great challenge. Herein, we specifically chose a lead bromine-based MOF (PbBr-MOF) with [Pb2Br3]+ nodes and utilized the uniform distribution of [Pb2Br3]+ to induce the in-situ confined growth of Cs4PbBr6 QDs via bottom-up mechanochemical approach for the first time, denoted as Cs4PbBr6@PbBr-MOF. The Cs4PbBr6 QDs uniform and firmly anchor in PbBr-MOF through [Pb2Br3]+ nodes, preventing their aggregation and enhancing quantum confinement effects. Highly dispersed Cs4PbBr6 QDs (3.86 ± 0.61 nm) exhibit high photoluminescence quantum yield (31%) and notable durability in various solvents. Furthermore, Cs4PbBr6@PbBr-MOF demonstrates excellent performance as a temperature sensor, with maximum absolute (Sa) and relative (Sr) temperature sensitivities of up to 0.013 K−1 and 3.41% K−1, respectively.

Near-Infrared Persistent Luminescence Nanoprobe for Early Detection of Atherosclerotic Plaque.

Atherosclerosis (AS) is a crucial contributor to various cardiovascular diseases (CVDs), which seriously threaten human life and health. Early and accurate recognition of AS plaques is essential for the prevention and treatment of CVD. Herein, we introduce an AS-targeting nanoprobe based on near-infrared (NIR) persistent luminescence nanoparticles (PLNPs), developing a highly sensitive NIR persistent luminescence (PersL) AS plaque imaging technique and successfully realizing early AS plaque detection. The nanoprobe exhibits good monodispersity and regular spherical morphology and also owns exceptional NIR PersL performance upon repetitive irradiation by biological window light. The surface-conjugated antibody (anti-osteopontin) endowed nanoprobe excellent targeting ability to foam cells within plaques. After intravenously injected nanoprobe into AS model mice, the highly sensitive PersL imaging technique can accurately detect AS plaques prior to ultrasonography (US) and magnetic resonance imaging (MRI). Specifically, the NIR PersL imaging reveals AS plaques at the earliest within 2 weeks, with higher signal-to-background ratio (SBR) up to 5.72. Based on this technique, the nanoprobe has great potential for applications in the prevention and treatment of CVD, the study of AS pathogenesis, and the screening of anti-AS drugs.

A fluorescent ratiometric potassium sensor based on IPG4-silica microparticles for selective detection and fluorescence imaging of potassium cations.

Potassium cations play many important roles in living organisms, especially in electro-physiology, since they are involved in neurotransmission and muscle contractions. We report the synthesis of a ratiometric fluorescent microsensor for potassium (K+) detection, based on the fluorescent probe ION potassium green 4. Potassium-sensitive fluorescent microparticles were obtained by using silica as the core material. We obtained silica-based microsensors with sizes in the micrometer range, spherical shapes, good monodispersity, optimal selectivity and a sensitivity range of 0 to 40 mM. The microsensors also proved to be non-toxic in cell cultures and suitable for fluorescence imaging, offering new possibilities for non-invasive optical detection, quantification and in situ monitoring of K+ variations in cell culture systems.

Biomass-derived Co, N and P co-doped 3D porous carbon as an effective electrocatalyst for oxygen reduction reaction

Fuel cells are an important and promising energy system which has attracted lots of attention. The research on non precious metal catalysts is extremely important for the development of fuel cells. In this work, we fabricated metal organic hybrids (MOH) from chitosan, phytic acid, and CoCl2 through a simple chemical method, and further obtained the Co, N, and P co-doped 3D porous carbon material, with the Co atoms exhibiting good monodispersity on the surface. Due to the size effect brought by the single atom doping of Co and the influence of N and P doping on the microenvironment of the active center, the obtained Co-NPC-6 M exhibits excellent catalytic performance for ORR in the alkaline aqueous electrolyte solution.

Boron and nitrogen co-doped carbon dots as the dual functional fluorescent probe for Fe3+ and pH detection

Carbon dots doped with boron and nitrogen atoms (B, N-CDs) were designed and prepared by hydrothermal strategy using citric acid, urea and borax as raw materials. The structure and optical properties of B, N-CDs were characterized by various characterization technologies. The results showed that the B, N-CDs exhibited good mono-dispersion, excellent fluorescence stability, and high fluorescence intensity (quantum yield up to 32 %). A dual-functional Fe3+ and pH detection platform based on B, N-CDs was constructed. The Fe3+ sensing method based on B, N-CDs fluorescence quenching showed an excellent linear relationship between 0.044–70 μM (R2 = 0.994), with a detection limit as low as 0.044 μM. Then, this detection method was successfully applied to the high-accuracy detection of Fe3+ in water samples and iron supplement tablets. The study of the quenching mechanism showed that the fluorescence of B, N-CDs was quenched by Fe3+ in two ways: static quenching and dynamic quenching. Moreover, B, N-CDs can also be used as a pH fluorescence sensor in the ranges of pH 2.0–4.8 and 5.2–7.6. The developed sensing system based on B, N-CDs has high selectivity and sensitivity for the detection of Fe3+, and a wide detection range for pH.

A simple photocatalytic assisted strategy by MIL-100 (Fe) for fabrication of polymer based on H-bonding as filtrate reducer to resist salt and temperature in ultra-deep wells

Improving the performance of water-based drilling fluids for high temperature, salt and calcium resistance in the exploration of deep and ultra-deep wells is a matter of great urgency. In this study, MIL-100 (Fe) nanosphere catalyst with regular shape, uniform size and good monodispersity is prepared ahead of time. XRD, SEM and BET tests indicates that the MIL-100 (Fe) owning large specific surface areas, adjustable pore sizes and high porosity can display to be a photocatalyst. Based on the excellent photocatalytic activity under visible light, a new one-pot method strategy was supposed to achieve the graft modification on N atom in acrylamide using aziridine, and obtained the multi-amine allyl monomer. Finally, the poly (AM/AMPS/PSMM) (PAAP) filtrate reducer with significant hydrogen bonding effect was successfully synthesized by free radical copolymerization with acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and the pre-synthesized multi-amine allyl monomer. Due to the three dimensional hydrogen bonding interaction and resulted supramolecular association structure, the PAAP-based drilling fluids exhibit outstanding rheological and filtration properties even after aging at high temperatures and high salinity. The filtration volume after aging at 180 °C for 16 h is only 6.0 mL, meanwhile, the 20 wt% NaCl and 1.5 wt% CaCl2 copolymer base slurry aged at 180 °C both show the satisfactory filtration loss and offering performance higher than commercial filtrate reducers. Specifically, after aging at 180 °C, the filtration losses of DSP-1/BM and DSP-2/BM were 19.8 and 37.2 mL with 20 wt% NaCl contamination, respectively, while the filtration loss of PAAP was only 10.8 mL. Even under both 1.5 wt% CaCl2 contamination and 180 °C aging, the filtration loss of PAAP was only 11.0 mL, whereas the filtration loss of DSP-1 and DSP-2 reached 26.0 and 20.0 mL. Finally, the filtration control mechanism of poly (AM/AMPS/PSMM) was proposed via XPS test, hydrogen bonding analysis, filter cake morphologies observation by SEM and particle size distribution measurement.

Pancreatic cancer cell line in responsive hydrogel microcapsules for drug evaluation

AbstractDrug therapies are the cornerstone of systemic treatment for pancreatic cancer patients. However, the relative outcome of drug evaluation is often hampered by the complex microenvironment of pancreatic cancer due to the lack of reasonable tumor models. Here, we proposed a novel platform that integrated pancreatic adenocarcinoma cells encapsulated into hydrogel microcapsules for three‐dimensional (3D) tumor cultivation and antitumor agent evaluation. These hydrogel microcapsules contain alginate/poly (N‐isopropyl acrylamide) (alginate/PNIPAM) shells and carboxymethyl cellulose cores, which are generated through the microfluidic electrospray technique. The microcapsules have the feature of rapid response to temperature, by which they can regulate the internal pressure environment. Besides, benefiting from good monodispersity, precise size control, and biocompatibility of these microcapsules, these wrapped tumor cells have the capacity for proliferating spontaneously and forming 3D tumor spheroids with good cell viability. We have demonstrated that pancreatic adenocarcinoma cells encapsulated in the composite microcapsules with different PNIPAM concentrations showed different drug sensitivity, which could be ascribed to the influence of external pressures environment. These results indicate that the tumor spheroids coated in these responsive microcapsules have great potential in the analysis of antitumor drug sensitivity.