Composite Nanospheres Research Articles

Natural-based UV-shielding additives to protect photosensitive pesticides: Production of nanoparticles from the co-self-assembly of lignin and tannin

This work explores the development of a renewable, carbon-neutral, light-colored UV-shielding film to protect photosensitive pesticides from solar radiation, as these chemicals are easily degraded under UV light, substantially reducing their efficiency and causing soil and water pollution. The abundant benzene rings in lignin and phenolic hydroxyls in tannin boosted the co-self-assembly of lignin and tannin into composite nanospheres by the simultaneous π-π stacking and H-bonding interactions between these two biopolymers. These lignin-tannin (LT) composite nanoparticles were used as natural UV-shielding additives to coat a poly-vinyl-alcohol (PVA) film, endowing the PVA-LT film with an excellent UV-shielding ability (>95 % efficiency) due to the strong π-π stacking and concentrated phenolic hydroxyls. Typical photosensitive pesticides covered with the PVA-LT film significantly increased their remaining rate by 1.5 times compared to those under the uncoated film. Besides, intensive intermolecular hydrogen bonds were generated between PVA and the abundant phenolic hydroxyl groups exposed on the hydrophilic shell of the LT coating, enhancing the mechanical properties and water vapor retention of the composite film. Our biodegradable composite film derived from natural plant extracts not only protected photosensitive pesticides from UV irradiation but also allowed the transmission of visible light to guarantee the photosynthesis process of crops.

Effects of spherical, disk-like and lamellar nanocomposite particles on cold flow behaviors of waxy crude oil

Wax precipitation and deposition are challenging hurdles in pipeline transportation of waxy crude oil. This study focuses on transforming SiO2, Laponite, and montmorillonite particles into hydrophobic particles through polymer grafting. Chemical structure analysis and grafting ratio calculation were performed. Through thermogravimetric analyzer (TGA) test, Laponite showed the highest grafting ratio. The effects of adding nanocomposites, TDA-2024-22, and commercial pour point depressants on the rheological behavior and wax crystallization behavior of African crude oil were compared. Addition of the nanocomposite PDA-22@SiO2 to crude oil, reduced the viscosity by 85.6% at 20 °C and the thixotropy by 60.2%. Wax crystal size decreased in the order of PDA-22@SiO2, PDA-22@Laponite, KS-10, TDA2024-22, and PDA-22@MMT. The pour point decreased by 6 °C with PDA-22@ SiO2 particles but only 3 °C with Laponite and montmorillonite composites. Spherical nanocomposites are promising flow improvers for waxy crude oil.

5-Fluorouracil/curcumin loaded silk fibroin hydrogel for the adjuvant therapy in colorectal cancer

This study employed silk fibroin (SF) as a carrier material to encapsulate curcumin (CUR) and 5-fluorouracil (5-FU), forming a highly effective drug-loaded hydrogel. The process involved mixing SF solution containing 5-FU with curcumin solution dissolved in acetone (AC), leading to the formation of composite drug-loaded nanospheres with particle sizes ranging from 77.87 nm to 299.22 nm, demonstrated enhanced permeability and retention (EPR) effects, enabling passive targeting of solid tumors. After the formation of the nanospheres, they were dispersed into a solution containing SF and polyethylene glycol (PEG). Following gelation and PEG removal, a SF hydrogel loaded with 5-FU and CUR (5-FU/CUR@SF hydrogel) was obtained. Results indicated that the 5-FU/CUR@SF hydrogel exhibited excellent drug release properties, with 5-FU and CUR achieving sustained release of 59.66 ± 3.76 % and 47.94 ± 5.03 %, respectively, over a 400-h of sustainable releasing period. Human colorectal cancer cell line (HT-29) and normal human colon epithelial cell line (NCM-460) were cultured with the 5-FU/CUR@SF hydrogel, resulting an apoptosis rate of only 17.38 ± 1.98 % for NCM-460 cells, whereas the apoptosis rate for HT-29 cells significantly increased to 72.31 ± 2.18 %, and its cell viability dropped to 59.77 ± 0.55 %. These findings suggest that the 5-FU/CUR@SF hydrogel exhibits low cytotoxicity toward normal NCM-460 cells, while exerting significant and sustained inhibitory effects on HT-29 cancer cells. In conclusion, the SF-based drug-loaded composite hydrogel holds great potential as a novel adjuvant therapeutic strategy for the treatment of CRC.

Electrochemical performance of MWCNT nanowires-decorated ZnCo2O4 sphere nanocomposite for an asymmetric capacitor

A composite material consisting of porous ZnCo2O4 sphere covered with MWCNT nanowires is synthesised using a hydrothermal technique and thermal annealing. The capacitive properties of the electrode materials are examined. The ZnCo2O4/MWCNT composites have superior capacitive performance in comparison to pure ZnCo2O4 hexagonal nanoplates. The ZnCo2O4/MWCNT composites have a specific capacitance of 2080 F/g at 1 A g−1. The cells also exhibit outstanding rate capacity, maintaining 600 F/g even at 5 A g−1. The nanocomposites have exceptional retention rate, as seen by an only 4.7 % decrease in specific capacitance over 10,000 cycles. The improved capacitive efficiency of ZnCo2O4/MWCNT composites may be ascribed to the structural benefits of large surface area, excellent electrical characteristics, and a well-established network provided by the MWCNT support. The ASC device has a significant energy density of 52.74 Whkg−1 while operating at a power density of 4205 Wkg−1. Additionally, it has an operating voltage window of 0–1.6 V. The excellent capacitive performance shows the potential use of ZnCo2O4/MWCNT composites as electrodes for hybrid capacitors.

A novel colored chitosan-modified polystyrene composite dye nanospheres with enhanced coloring properties for binder-free printing

The limited utilization rate of dyes for coloring coupled with the consumption of large quantities of chemical reagents, can result in acute environmental pollution and waste of resources. Herein, in accordance with the electrostatic attraction between electropositivity of chitosan and anionic dyes, a novel type of chitosan-modified cationic polystyrene nanospheres (PSCS) was creatively synthesized, which can be innovatively employed as a special carrier with an adsorption capacity of up to 197.4mg/g for acid dyes. Consequently, a exclusive pigment identified as colored chitosan-modified polystyrene composite dye nanospheres (PSCS(AR9)) was procured. Simultaneously, the binder-free printing was accomplished by leveraging the intrinsic self-curing property of PSCS(AR9) for screen printing of textiles. Additionally, printed fabrics with PSCS(AR9) exhibited superb darkening effect (the K/S value can be increased by 2 times.) in conjunction with significantly improved hand feel in contrast with the conventional printed fabrics. The last but not least, the rubbing fastness of the printed fabrics using PSCS(AR9) can meet demand of the practical application. Therefore, this work may provide an innovative insight for constructing a new type of environmentally friendly and depth-enhanced printed textile.

Bio-inspired synthesis of Cm-Ag/NiO nanocomposites: Enhanced photocatalytic degradation of textile dyes

This study successfully syntheses Cm-Ag/NiO nanocomposites (NCs) using an eco-friendly approach with Cucumis maderaspatanus L. leaf extract, highlighting a promising avenue for sustainable nanomaterial development. The nanocomposites were calcined at temperatures ranging from 300 to 700 °C to optimize their bandgap, achieving a value of 2.94 eV as determined by UV-Tauc plots. Characterization techniques revealed a face-centered cubic structure via X-ray diffraction, while transmission electron microscopy (TEM) showed uniformly spherical NCs with an average particle size of 7.1 nm. X-ray photoelectron spectroscopy (XPS) confirmed the elemental composition and oxidation states, while thermogravimetric analysis (TGA) and zeta potential measurements indicated robust thermal and colloidal stability. Photocatalytic experiments demonstrated degradation efficiencies of 83.16 % for the textile dye BB41 and 90.19 % for ROM2R under optimized conditions, with degradation kinetics following a first-order reaction model. Additionally, degradation products were identified via LC-MS, and toxicity was evaluated using ECOSAR software, shedding light on the environmental implications of our photocatalytic process. These findings establish Cm-Ag/NiO NCs as highly effective photocatalysts and sustainable solutions for addressing dye pollution in wastewater treatment, paving the way for innovative applications in environmental remediation.

Portable Colorimetric Sensor Array Based on a Porous Single‐Atom Fe Nanozyme with Different Surface Sites for Identifying Artificially Ripened Fruits

AbstractSingle‐atom nanozyme materials have demonstrated exceptional specific catalytic activity due to the atomic‐level dispersion of their active centers. However, the exploration of catalytic mechanisms for single‐atom catalysts is so far limited to the 2D surfaces of nanozymes. In this study, porous single‐atom Fe nanozyme (psaFeN) is successfully prepared through a straightforward coordination‐assisted polymerization‐assembly strategy. The psaFeN composite nanospheres are uniformly sized, exhibiting excellent dispersibility with well‐organized pore channels extending from the center to the surface. Density functional theory calculations reveal that in the psaFeN nanozyme, the (010) facets serve as the primary active surface, where Fe atoms form tri‐coordinated or tetra‐coordinated structures with doped nitrogen atoms. The (100) facets act as auxiliary reactive surfaces with tetra‐coordinated Fe─N as the active center. psaFeN exhibits excellent POD‐like activity (Km = 1.77 mM; Vmax = 173.53 × 10−⁸ M s−1). Given this exceptional bioactivity, a portable colorimetric biosensor is constructed for distinguishing artificially ripened fruits from naturally ripened ones. The sensor achieves precise discrimination with a detection limit as low as 310 nmol L−1. This study is anticipated to offer valuable insights into understanding the 3D catalytic mechanisms of single‐atom nanozymes, promoting their application in the development of robust biosensors for food safety.

Synthesis of magnetic ferrite/carbon nano sphere composites (MFe2O4/CNS, M = Mn, Ni, Zn) for Rhodamine B degradation by catalyzing persulfate

Synthesis of magnetic ferrite/carbon nano sphere composites (MFe2O4/CNS, M = Mn, Ni, Zn) for Rhodamine B degradation by catalyzing persulfate

Enhancing the performance of lithium-ion batteries with NiCo2S4/C-hollow sphere nanocomposites

Enhancing the performance of lithium-ion batteries with NiCo2S4/C-hollow sphere nanocomposites

Uncovering fantastic synergistic lithium adsorption with manganese-titanium based composite nanospheres: Mild synthesis and molecular dynamics simulation insights

In light of the burgeoning energy technology sector and the ever-growing demand for lithium across diverse industrial domains, conventional lithium extraction methods have been proven inadequate due to their limited production capacity and high operational costs. This work introduces a novel approach to the manganese-titanium based composite HMTO (Mn:Ti=1:4) lithium ion-sieve (LIS) nanospheres, employing lithium acetate dihydrate, manganese carbonate and titanium dioxide P25 as the primary materials. These nanospheres exhibit relatively uniform spherical morphology, narrow size distribution, small average particle size (ca. 55 nm), large specific surface area (43.58 m2 g−1) and high surface O2− content (59.01%). When utilized as the adsorbents for Li+ ions, the HMTO (Mn:Ti=1:4) LIS demonstrates a fast adsorption rate, approaching equilibrium within 6.0 h with an equilibrium adsorption capacity (qe) of 79.5 mg g−1 and a maximum adsorption capacity (qm) of 87.26 mg g−1 (initial concentration C0: 1.8 g L−1). In addition, the HMTO (Mn:Ti=1:4) also delivers a high lithium extraction from the simulated high magnesium-lithium molar ratio salt lake brine (Mg:Li = 103), achieving a qe of 33.85 mg g−1 along with a remarkable selectivity (αMgLi=2192.76). Particularly, the HMTO (Mn:Ti=1:4) LIS showcases a satisfactory recycling adsorption performance. The adsorption capacity remains at a high level, even that determined after the 5th cycle (55.45 mg g−1) surpasses that of the most recently reported adsorbents. Ultimately, the fantastic synergistic lithium adsorption mechanism is deliberately uncovered by leveraging the ion exchange principles and molecular dynamics (MD) simulations.

Eminent Red Sea water hydrogen generation via a Pb(ii)-iodide/poly(1H-pyrrole) nanocomposite photocathode

Abstract The development of a photocathode based on a Pb(ii)-iodide/poly(1H-pyrrole) porous spherical (PbI2/P1HP PS) nanocomposite has been successfully achieved in the efficient production of H2 gas from Red Sea water. The distinguishable spherical and porous shapes of these nanocomposites are characterized by a minimum surface measuring approximately 25 nm. This structural configuration, coupled with the nanocomposite’s substantial light absorbance, results in a modest bandgap of 2.4 eV. This turns the nanocomposite into a highly promising candidate for renewable energy applications, particularly for H2 gas generation from natural sources like Red Sea water. The economic viability of the PbI2/P1HP PS nanocomposite, relying on a glass substrate, mass production, and straightforward fabrication techniques, adds to its promising profile for H2 gas evolution. The photocathode exhibits significant potential for H2 gas production, with a notable current density (J ph) value of 1.0 mA·cm−2 in a three-electrode cell configuration. The IPCE reaches 3.1%, reflecting the successful evolution of 24 µmol·h−1 10 cm2 of the photocathode. Importantly, the use of natural Red Sea water as an electrolyte underscores a key feature for H2 gas production: utilizing freely available natural resources. This aspect holds considerable promise for industrial applications, emphasizing the environmentally sustainable nature of the photocathode.

Cobalt (II) porphyrin nanoaggregates as sacrificial templates to improve the peroxidase-like activity of light-controlled TiO2-based nanozymes for colorimetric determination of amikacin

Although porphyrin modification can improve the peroxidase-like activity of some inorganic nanozymes, it is hardly studied that metal porphyrin self-assembled nanoaggregates as sacrificial templates to turn on the peroxidase-like activity of inorganic nanozymes under light illumination. In this work, cobalt (II) 5,10,15,20-Tetrakis (4-carboxylpheyl)porphyrin (CoTCPP) self-assembled nanoaggregates are firstly used as soft templates to prepare TiO2-based nanozymes with the enhanced peroxidase-like activity. Interestingly, CoTCPP nanoaggregates can be changed into Co oxide nanoparticles dispersed into the nanosphere composites. Furthermore, the peroxidase-like activity of CoTCPP-TiO2 nanospheres can be controlled by light illumination. Comparatively, CoTCPP-TiO2 nanoshperes exhibit the highest peroxidase-like activity of three nanospheres (CoTCPP-TiO2, H2TCPP-TiO2 and TiO2) with similar morphology under the light illumination. Other than the existence of oxygen vacancy, the formation of heterostructure between TiO2 and a small amount of Co3O4 are ascribed to increase the catalytic activity of CoTCPP-TiO2 composites. Thus, a facile and convenient colorimetric sensing platform has been constructed and tuned by light illumination for determining H2O2 and amikacin in a good linear range of 20–100 and 50–100 μM with a limit of detection (LOD) of 3.04 μM and 1.88 μM, respectively. The CoTCPP-TiO2 based colorimetric sensing platform has been validated by measuring the amikacin residue in lake water.

Diphasic CeO2 Nanocrystal/Bioactive Glass Nanosphere-Based Composite Hydrogel for Diabetic Wound Healing by Reactive Oxygen Species Scavenging and Inflammation Regulation.

Background: Antioxidant therapy aimed at reducing excessive local oxidative stress is one of the most important strategies for promoting diabetic wound repair. The reversible transformation of Ce3+/Ce4+ in ceria (CeO2) can reduce excessive local oxidative stress. However, inducing angiogenesis, local anti-inflammatory effects, and other positive effects are challenging. Therefore, ideal dressings for chronic diabetic wound management must concurrently reduce excessive oxidative stress, promote angiogenesis, and have anti-inflammatory effects. Methods: In this study, Ce-doped borosilicate bioactive glasses (BGs) were prepared using the sol-gel method, and CeO2 nanocrystals (CeO2-NCs) were precipitated on the glass surface by heat treatment to obtain BG-xCe composite glass nanospheres. Subsequently, nanospheres were modified by amino group and combined with dopamine and acrylamide to obtain BG-xCe/polydopamine/polyacrylamide (PDA/PAM) composite hydrogel. Then, the morphology and properties of composite hydrogels were detected, and the properties to treat the diabetic wounds were also evaluated. Results: The results demonstrated that the BG-10Ce/PDA/PAM composite hydrogel possessed excellent tensile and adhesive properties. Invitro, the migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) and fibroblasts (L929) were enhanced by reducing reactive oxygen species (ROS) levels in the conditioned medium. Animal experiments have shown that CeO2-NCs in hydrogels effectively scavenge ROS in diabetic wounds, and Sr dissolved from the glassy phase can modulate macrophage polarization to the M2 phenotype. Conclusions: The synergistic effect of both amorphous materials and nanocrystals provides the BG-10Ce/PDA/PAM composite hydrogel with great potential for diabetic wound healing.

Synthesis of Fe3O4@SiO2–branched polyethylenimine nanospheres for removal of Cr(VI) and anionic dyes

There is a need to design and prepare new sorbents for the effective elimination of toxic metal ions and textile dyes from the environment. In the presented study, the preparation of magnetic functionalized silica composite nanospheres for the removal of inorganic and organic pollutants from aqueous solutions is reported. Firstly, the surface of silica coated magnetic nanospheres was functionalized with epoxy groups via a reaction of 3-glycidoxypropyltriethoxysilane. Then, the branched polyethylenimine (BPEI) was attached to generate positive functional charged groups on the on the Fe3O4@SiO2. The performance of the Fe3O4@SiO2-BPEI nanospheres for the removal of Cr(VI) and Congo Red (CR) and Trypan Blue (TB) dyes was studied under various experimental conditions. The optimum pHs values for adsorption of Cr(VI) ions, CR and TB dyes on the Fe3O4@SiO2-BPEI nanospheres were found to be at pH 2.0, and at pH 4.0, respectively. The maximum adsorption capacities of the Fe3O4-@SiO2-BPEI nanospheres for Cr(VI), CR, and TB were obtained as 356.7, 395.3, and 561.8 mg/g within 90 min equilibrium time, an initial concentration of 500 mg/L, and at 25 ºC, respectively. The adsorption of the tested pollutants were well described by the Langmuir isotherm model and second-order kinetic model. After ten reuse cycles, the adsorption capacity of Fe3O4-@SiO2-BPEI nanospheres was not significantly changed for the tested pollutants. The adsorption mechanism of Cr(VI), CR, and TB by the Fe3O4-@SiO2-BPEI nanospheres was evaluated to be related to ion exchange and ion exchange and/or hydrogen bonding interactions, respectively. The results also suggested that the presented adsorbent may serve as a multi-functional adsorbent for the remediation of industrial effluents. In addition, compared to the unmodified Fe3O4@SiO2, the Fe3O4@SiO2-BPEI nanospheres have antibacterial activities against Escherichia coli (American Type Culture Collection (ATCC) 12435), Pseudomonas aeruginosa (ATCC 10145), Listeria monocytogenes (ATCC 7644), and Staphylococcus aureus (ATCC 43300). Based on the obtained results from this work, the branched polyethylene functionalized magnetic silica nanospheres with antibacterial properties can be used as a potential adsorbent for the removal of metal ions and anionic dyes from wastewater.

Synthesis and characterisation of tamarind seed husk-derived carbon quantum dots incorporated polypyrrole nanosphere composite for energy storage applications

ABSTRACT In this study, the green synthesis of Tamarind Seed Husk-derived carbon quantum dots (TCQDs) by using a facile one-step hydrothermal technique and Tamarind Seed Husk-derived carbon quantum dots/Polypyrrole nanosphere composites (TCQDs/PPy-NS) was synthesised by using the facile in-situ chemical polymerisation method. These results suggest that the TCQDs/PPy-NS composite electrode is a promising electrode for high-energy storage applications. The TCQDs/PPy-NS composite offers an effective supercapacitor electrode material by blending the superior electrical conductivity of TCQDs with the increased pseudocapacitive capacity of polypyrrole nanospheres (PPy-NS). The TCQDs/PPy-NS composite exhibits a specific capacity (Csp) of 400 Fg−1 at a current density (CD) of 2 Ag−1, and a solid-state flexible symmetric supercapacitor (SSC) was developed using the TCQDs/PPy-NS composite to meet an excellent power density (PD) of 1008.19 Wkg−1 at an energy density (ED) of 31.02 Whkg−1 It also demonstrated excellent cycling stability with a capacity retention and coulombic efficiency of 84.57% and 98.06% after 4000 cycles at 2 Ag−1 respectively. This remarkable flexibility and stability make the TCQDs/PPy-NS SSC device highly suitable for applications in wearable electronics and flexible energy storage systems.

Magnetically Induced Thermal Effects on Tobacco Mosaic Virus-Based Nanocomposites for a Programmed Disassembly of Protein Cages.

Protein cages are promising tools for the controlled delivery of therapeutics and imaging agents when endowed with programmable disassembly strategies. Here, we produced hybrid nanocomposites made of tobacco mosaic virus (TMV) and magnetic iron oxide nanoparticles (IONPs), designed to disrupt the viral protein cages using magnetically induced release of heat. We studied the effects of this magnetic hyperthermia on the programmable viral protein capsid disassembly using (1) elongated nanocomposites of TMV coated heterogeneously with magnetic iron oxide nanoparticles (TMV@IONPs) and (2) spherical nanocomposites of polystyrene (PS) on which we deposited presynthesized IONPs and TMV via layer-by-layer self-assembly (PS@IONPs/TMV). Notably, we found that the extent of the disassembly of the protein cages is contingent upon the specific absorption rate (SAR) of the magnetic nanoparticles, that is, the heating efficiency, and the relative position of the protein cage within the nanocomposite concerning the heating sources. This implies that the spatial arrangement of components within the hybrid nanostructure has a significant impact on the disassembly process. Understanding and optimizing this relationship will contribute to the critical spatiotemporal control for targeted drug and gene delivery using protein cages.

Fluorescence Enhancement of CdS:Ag Quantum Dots Co-Assembled with Au Nanoparticles in a Hollow Nanosphere Form.

Colloidal quantum dots (QDs) have exceptional fluorescence properties. Overcoming aggregation-induced quenching and enhancing the fluorescence of colloidal QDs have remained a challenging issue in this field. In this study, composite hollow nanospheres composed of Au nanoparticles (NPs) and CdS:Ag-doped QDs were successfully constructed through controlled microemulsion-based cooperative assembly. This method harnessed the localized surface plasmon resonance (LSPR) effect of Au NPs nearby doped QDs, resulting in enhanced doped QD fluorescence and the observation of the Purcell effect. The composite hollow nanospheres show a fluorescence enhancement compared to that of the pure CdS:Ag QDs. The enhanced fluorescence was demonstrated to come from the synergetic enhancement of the absorption and emission transition of the doped QDs. This approach provides a feasible technological pathway to address the challenge of improving the fluorescence performance of the doped QDs.

MOF-derived porous In2O3 nanospheres sensitized by CdS quantum dots: A ppb-level NO2 sensor with ultra-high response at room-temperature

NO2 is one of the most important atmosphere pollutants, causing great harm to the human body at very low concentrations (ppb levels). Herein, a novel fabrication idea for gas sensing materials was reported to detect ppb-level NO2 via MOF-derived porous In2O3 nanospheres (NSs) sensitized by CdS quantum dots (QDs). The good distribution of CdS QDs (2.5–4.0 nm) on porous In2O3 NSs was verified by the transmission electron microscopy and element mapping analyses. In comparison to In2O3 NSs, the CdS@In2O3 composite nanospheres (CNSs) exhibited exceptional responses to ppb-level concentrations of NO2 (S=425.1@100 ppb) at room temperature (RT, 25 °C), while also demonstrating good selectivity and response reproducibility. These improvements in sensing performance were attributed to the synergies of the electronic effects of CdS QDs, MOF-derived porous nanostructures, and enhanced adsorption of NO2 and active O2– by well-dispersed CdS QDs. This work emphasizes that the MOF-derived In2O3 porous NSs sensitized by CdS QDs can accurately detect ppb-level concentrations of the NO2 at RT.

Multiplex fluorescence quenching immunoassay based on multicolor magnetic quantum dot and dual spectral-overlapped polydopamine nanospheres for ultrasensitive detection of aflatoxin B1, zearalenone, ochratoxin A, and fumonisin B1

Due to the increasing fungal infections and the implementation of strict food safety regulations, the demand for sensitive, rapid, and easy assays for testing co-contaminated mycotoxins in food has grown in recent years. In this study, a multiplex fluorescence quenching immunoassay is developed to simultaneously detect prevalent mycotoxins in cereals, namely aflatoxin B1 (AFB1), zearalenone (ZEN), ochratoxin A (OTA), and fumonisin B1 (FB1). Four spherical nanocomposites with magnetic core and three-layer quantum dot (QD) shell (MagTQD) are fabricated. These nanocomposites exhibit different maximum emission peaks without overlap and interference at the same excitation wavelength. Four MagTQD conjugated with corresponding coating antigens to prepare four fluorescence signal probes with rapid magnetic enrichment ability, respectively. Moreover, polydopamine nanospheres (PDANs) with dual-spectral overlapped fluorescence quenching properties are conjugated with four mycotoxin antibodies to prepare four fluorescence quenching probes, respectively. The established immunoassay has the low detection limit at 1.29 pg mL−1 for AFB1, 0.80 pg mL−1 for ZEN, 1.97 pg mL−1 for OTA, and 13.89 pg mL−1 for FB1, respectively. This developed assay can provide a new approach to realize the efficient detection of multi-mycotoxins in food safety supervision.

Copper Quantum Dot/Polyacrylamide Composite Nanospheres: Spreading on Quartz Flake Surfaces and Displacing Crude Oil in Microchannel Chips.

Polyacrylamide, silica, and other nanoparticles have all been realized in the field of enhanced oil recovery. Researchers often explore the mechanisms of spreading behavior and simulated displacement to develop more efficient types of nanoparticles. In this study, copper quantum dots were introduced into a acrylamide copolymerization system to obtain composite nanospheres and its structure, topographic, and application performance were characterized. The results show that the composite nanospheres have a particle size of around 25 nm, are uniformly loaded with copper particles, and have good temperature resistance. The spreading ability on the quartz flake surfaces and displacement effect in microchannels of composite nanospheres, acrylamide copolymer nanospheres, and copper quantum dots were compared by nanofluid spreading experiments and microchannel chip oil displacement experiments. The results indicate that the composite nanospheres can effectively reduce the water contact angle, promote the spreading of aqueous phase, and accelerate the oil droplet removal process; the accelerating effect is stronger than other samples. Its oil displacement effect is also the strongest, and it is minimized by the influence of channel size, temperature, and dispersing medium, with better stratigraphic adaptability. This work supports the practical application of copper quantum dot/polyacrylamide composite nanospheres in the oilfield.