Green delivery carriers of nanopesticides, like sophorolipid biosurfactants, are of great significance to reduce environmental pollution and promote sustainable agricultural development. However, the molecular diversity of an unisolated sophorolipid mixture with almost unpredictable self-assembly properties has limited the in-depth study of its structure−activity relationship and hindered the development of green pesticide delivery systems. In this work, the acidic and lactonic sophorolipids were successfully separated from the sophorolipid mixture through silica gel column chromatography. A series of cost-effective green nanopesticides loaded with lambda-cyhalothrin (LC) were rapidly fabricated based on a combination of the acidic and lactonic sophorolipids as surfactants by flash nanoprecipitation. The effects of the acidic-to-lactonic ratio on particle size, drug loading capacity, and biological activity against Hyphantria cunea of LC-loaded nanoparticles were systematically investigated. The resultant nanopesticides exhibited a better insecticidal efficacy than a commercial emulsifiable concentrate formulation. This work opens up a novel strategy to construct scalable, cost-effective, and environmentally friendly nanopesticide systems.
Distinct platinum (Pt) nanozymes as peroxidase mimics have received extensive interest owing to their outstanding catalytic activity, high environmental tolerance, lower consumption, and great potential in replacing natural enzymes. However, easy agglomeration of Pt nanoparticles (Pt NPs) resulting from the high surface free energy significantly decrease their peroxidase-like activity. Herein, spherical polyelectrolyte brush (SPB)-stabilized ultrasmall Pt NPs (SPB@Pt NPs) were prepared by a novel synthetic strategy where the SPB not only performed as a nanoreactor for the synthesis of ultrasmall Pt NPs but also greatly stabilized Pt NPs against aggregation. The well-defined SPB@Pt NP nanozymes exhibited outstanding peroxidase-like activity for the catalytic oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB and were then used to establish a colorimetric sensor for rapid detection of cysteine, giving a limit of detection of 0.11 μM. Moreover, the colorimetric detection system was demonstrated with outstanding performance in sensitive and selective detection of cysteine in the presence of several interference molecules. From these results, SPB@Pt NPs have been regarded as promising peroxidase mimics for a large number of applications such as in biosensing, biomedicine, the food industry, and environmental chemistry.
Nanosized gold nanoparticles (AuNPs) are of great interest in areas such as catalysts or imaging but are easy to aggregate due to high surface activity. To stabilize AuNPs, two approaches were employed to immobilize AuNPs in spherical polymer brushes (SPBs), namely, the in situ preparation of AuNPs within the brush layer of SPBs and external addition of preprepared citrate-capped AuNPs. The distribution and stability of AuNPs in SPBs were studied by small-angle X-ray scattering (SAXS). SAXS results demonstrated that the in situ-prepared AuNPs were mainly located on the inner layer and their amount decreased from inside to outside. In the case of external addition of preprepared AuNPs, the cationic SPB showed obvious immobilization, while almost no AuNPs were immobilized in the anionic SPB. The stable immobilization of the AuNPs in SPBs was the result of multiple interactions including complexation and electrostatic interaction. SAXS was validated to be a distinctive and powerful characterization method to provide theoretical guidance for the stable immobilization of AuNPs.
Flash nanoprecipitation (FNP) is an efficient technique for encapsulating drugs in particulate carriers assembled by amphiphilic polymers. In this study, a novel nanoparticular system of a model drug curcumin (CUR) based on FNP technique was developed by using cheap and commercially available amphiphilic poly(vinyl pyrrolidone) (PVP) as stabilizer and natural polymer chitosan (CS) as trapping agent. Using this strategy, high encapsulation efficiency (EE > 95%) and drug loading capacity (DLC > 40%) of CUR were achieved. The resulting CUR-loaded nanoparticles (NPs) showed a long-term stability (at least 2 months) and pH-responsive release behavior. This work offers a new strategy to prepare cost-effective drug-loaded NPs with high drug loading capacity and opens a unique opportunity for industrial scale-up.
Background. It is important to improve the understanding of the fracture healing process at the molecular levels, then to discover potential miRNA regulatory mechanisms and candidate markers. Methods. Expression profiles of mRNA and miRNA were obtained from the Gene Expression Omnibus database. We performed differential analysis, enrichment analysis, protein-protein interaction (PPI) network analysis. The miRNA-mRNA network analysis was also performed. Results. We identified 499 differentially expressed mRNAs (DEmRs) that were upregulated and 534 downregulated DEmRs during fracture healing. They were mainly enriched in collagen fibril organization and immune response. Using the PPI network, we screened 10 hub genes that were upregulated and 10 hub genes downregulated with the largest connectivity. We further constructed the miRNA regulatory network for hub genes and identified 13 differentially expressed miRNAs (DEmiRs) regulators. Cd19 and Col6a1 were identified as key candidate mRNAs with the largest fold change, and their DEmiR regulators were key candidate regulators. Conclusion. Cd19 and Col6a1 might serve as candidate markers for fracture healing in subsequent studies. Their expression is regulated by miRNAs and is involved in collagen fibril organization and immune responses.
Gold nanoparticles (AuNPs) on carriers have received wide attention as catalysts as a result of their excellent stability and catalytic performance. Herein, we report the design and synthesis of hollow silicasupported gold nanocatalysts (SNPs@AuNPs) composed of highly dispersed AuNPs with approximately 4.30 nm using an in situ colloidal polyelectrolyte template strategy. The monodisperse polystyrene nanospheres accompanied by poly [(2-methacryloyloxyethyl)trimethylammonium chloride] brushes were first synthesized. Subsequently, the facile polymer-brush-engaged strategy for the synthesis of hollow SNPs@AuNPs involves in situ reduction of AuNPs, hydrolytic condensation of silica, and a chemical etching process. In combination with dynamic light scattering, transmission electron microscopy, small-angle X-ray scattering, X-ray powder diffraction, and Fourier transform infrared spectroscopy, the as-obtained polymer brushes were proven as effective versatile nanoreactors for the synthesis of AuNPs and silica nanoparticles without any catalysts. Benefiting from the structural advantages, the resultant hollow SNPs@AuNPs manifested superior catalytic activity and reusability for the reduction of p-nitrophenol by sodium borohydride in aqueous solution. With a delicate design, we believe that this synthetic strategy can be extended to fabricate multifunctional nanomaterials with diverse compositions, which would be of great interest in catalysis, energy, and many other important domains.
It is highly desirable to develop smart and green pesticide nanoformulations for improving pesticide targeting and reducing their inherent toxicity. Herein, we demonstrate a continuous nanoprecipitation method to construct a novel type of enzyme-responsive fluorescent nanopesticides (denoted as ABM@BSA-FITC/GA NPs) based on abamectin, fluorescein isothiocyanate isomer (FITC)-modified protein, and food-grade gum arabic. The as-prepared ABM@BSA-FITC/GA NPs exhibit good water dispersibility, excellent storage stability, and enhanced wettability compared to commercial formulations. The controlled release of pesticides can be achieved through protein degradation caused by trypsin. Most importantly, the deposition, distribution, and transport of the ABM@BSA-FITC/GA NPs are precisely tracked on target plants (cabbage and cucumber) by fluorescence. Furthermore, the ABM@BSA-FITC/GA NPs show the high control efficacy against Plutella xylostella L., which is comparable with commercial emulsifiable concentrate formulation. In consideration of its eco-friendly composition and absence of organic solvent, this pesticide nanoformulation has promising potential in sustainable plant protection.
A flash nanoprecipitation technique was developed for the construction of a novel type of deformable hollow organosilica nanoparticle for pesticide delivery.
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