Layer-by-layer assembled decomposable nanocapsules for light-responsive release of pesticide imidacloprid on Aphis craccivora Koch.

BACKGROUND: Conventional pesticide formulations are often inefficient because of low biological uptake after spraying. Controlled release nanopesticides can release pesticides precisely in response to specific stimuli, thereby killing pests and pathogens using the least effective concentration. This study aims to develop nanocapsule-based photo-decomposable nanopesticides for efficient pesticide control. RESULTS: The target nanopesticides were successfully fabricated using layer-by-layer assembly of the negative azobenzene-grafted hyaluronic acid (azo-HA) and positive polydimethyldiallylammonium chloride (polyDADMAC), confirmed by UV-visible, dynamic light scattering, Zeta potential and transmission electron microscopy measurements. The particle size and Zeta potential of the fabricated nanocapsules were 220 nm and +46.1 mV, respectively, and the nanocapsules were found to remain stable for up to 30 days. The optimized drug loading and encapsulation ratio of imidacloprid (IMI) in IMI/azo-HA@polyDADMAC were 21.5% and 91.3%, respectively. Cumulative release of IMI from the nanopesticides increased from ~50% to ~95% upon UV light irradiation (365 nm). The half lethal concentration (LC50) value of the nanopesticides toward Aphis craccivora Koch decreased from 2.22 to 0.55 mg L-1 upon UV light irradiation. CONCLUSION: The trans to cis transformation of the azo group in HA decomposed IMI/azo-HA@polyDADMAC nanopesticides upon UV irradiation, thus facilitating the release of IMI, resulting in a decrease in the concentration of pesticides required for efficient pesticide control. Our work demonstrated the great potential of light-responsive nanocapsules as a controlled release nanocarrier for efficient and eco-friendly pesticide control in sustainable agriculture. © 2024 Society of Chemical Industry.

Enhanced fungicidal efficacy and improved interfacial properties with the co-delivery of prothioconazole and tebuconazole using polylactic acid microspheres.

BACKGROUND: Prothioconazole (PTC) is one of the leading fungicide products worldwide. However, excessive use of PTC facilitates the development of resistance. Pesticide compounding technology plays an important role in reducing pesticide resistance. Microspherization technology for the construction of pesticide dual-loaded systems has recently provided a new direction for researching novel and efficient pesticide formulations. In this study, prothioconazole-tebuconazole@polylactic acid microspheres (PTC-TBA@PLA MS) were constructed by combining these two technologies. RESULTS: The final PTC-TBA@PLA MS were selected by an orthogonal method, which were uniformly spherical with smooth surface. The resultant drug loading (DL) and average particle size of PTC-TBA@PLA MS were 31.34% and 22.3 µm, respectively. A PTC-TBA@PLA MS suspending agent (SC) with a high suspension rate of 94.3% was prepared according to the suspension rate, dumping ability and stability. Compared with a commercial SC, the PTC-TBA@PLA MS SC had a larger cumulative release and better interfacial properties. Biological experiments showed that PTC-TBA@PLA MS SC had an obviously improved bactericidal effect than the commercial SC. CONCLUSION: The constructed PTC-TBA@PLA MS system detailed here is expected to reduce the risk of resistance and the frequency of pesticide use while enhancing fungal control. © 2023 Society of Chemical Industry.

An integrative method for evaluating the biological effects of nanoparticle-protein corona.

BACKGROUND: Nanoplastics in the environment can enter the human body through gastrointestinal intake, dermal contact, and pulmonary inhalation, posing a threat to human health. Protein molecules in body fluids will quickly adsorb on the surfaces of the nanoplastics, forming a protein corona, which has implications for the interaction of the nanoplastics with cells and the metabolic pathways of the nanoplastic within cells. For years, practical tools such as dynamic light scattering, transmission electron microscopy, and liquid chromatography have been developed to understand the protein corona of nanoparticles (NPs), either in vitro or in cellular or molecular level. However, an integrated approach to understand the nanoparticles-protein corona is still lacking. METHODS: Using the most frequently observed environmental nanoplastics, polystyrene nanoplastics (PS), as a standard, we established an integrative structural characterization platform, a biophysical and biochemical evaluation method to investigate the effect of surface charge on protein corona composition. The cellular and molecular mechanisms were also explored through in vitro cellular experiments. RESULTS: The first integrative method for characterizing biological properties of NPs-protein corona has been established. This method comprehensively covers the critical aspects to understand NPs-protein corona interactions, from structure to function. CONCLUSIONS: The integrative method for nanoplastics microstructure characterization can be applied to the structural characterization of nanoparticles in nanoscale, which is of universal significance from in vitro characterization to cellular experiments and then to molecular mechanism studies. GENERAL SIGNIFICANCE: This strategy has high reliability and repeatability and can be applied both in environment and nanomedicine safety assessment.

Efficient oral delivery of water-soluble CT contrast agent using an W1/O/W2 alginate hydrogel matrix.

HYPOTHESIS: Iohexol (IOH) is a commonly used second-generation nonionic iodinated contrast agent. However, low gastrointestinal mucosal adherence and high downstream speed limit its application in intestinal Computed tomography (CT) imaging. We hypothesize that oral IOH delivery carriers composed of environmentally responsive materials enable the intestinal targeted delivery and prolong the intestinal residence time of IOH, enhancing the intestinal disease detection efficiency. EXPERIMENTS: An emulsion-filled alginate hydrogel system was developed as the intestinal targeting vehicle for IOH. The formulation optimization was determined by response surface analysis. After a thorough study of the physicochemical properties of this hydrogel matrix, the pH sensitivity and the ability to control release were investigated, followed by a vitro cell experiment evaluating its bioactivity and CT imaging capability. FINDINGS: This alginate hydrogel matrix was sparsely structured and rapidly released IOH at pH 7.4. Meanwhile the swelling degree was 4.4 times higher than that at pH 1.2, indicating a good selective responsiveness to the gastrointestinal simulated environment. It improved the CT visual contrast of A549 cells without affecting cell morphology, suggesting that it would be an effective oral administration for water-soluble nonionic contrast agents and a potential candidate for intestinal disease detection tools.

Imidacloprid-loaded mesoporous silica nanoparticles simultaneously coated with myristyl alcohol and polydopamine for NIR-triggered delivery on Aphis craccivora Koch.

The stimuli-responsive degradation of coating layer on pesticide-loaded mesoporous silica nanoparticles (MSNs) can realize on-demand release of pesticides. Herein, we report the simultaneously coating of imidacloprid (IMI)-loaded MSNs with phase change materials (PCMs) and polydopamine (PDA) to realize NIR-triggered release of IMI. To balance good thermal stability and sensitive thermal responsiveness, myristyl alcohol (MA) was selected as optimal PCM for IMI@MSNs@MA-PDA nanocomposites. The successful preparation of IMI@MSNs@MA-PDA nanocomposites was confirmed by FT-IR, small angle XRD, SEM, TEM, TGA and BET. MSNs@MA-PDA nanocomposites exhibited concentration and irradiation power dependent stable photothermal conversion ability, with the maximum temperature increase of 23.3 â„ƒ (808 nm, 2 W/cm2, 300 µg/mL). The drug loading and encapsulation efficiency of IMI were 30.1% and 43.0%, respectively. The cumulative release of IMI from IMI@MSNs@MA-PDA was increased by ∼30% when the temperature was increased from 25 â„ƒ to 38 â„ƒ. Meanwhile, initial burst release of IMI from MSNs was inhibited. Finally, in vivo insecticidal activity of IMI@MSNs@MA-PDA was evaluated on Aphis craccivora Koch. The LC50 value was decreased from 5.01 mg/L to 3.73 mg/L, resulted from photothermal-boosted release of IMI. Our facile and effective method to prepare MSNs-based photothermal-responsive pesticide delivery system can be generalized to prepare other nanomaterials-based delivery systems for efficient and eco-friendly pesticide-control in agriculture.

Enhanced Insecticidal Effect and Interface Behavior of Nicotine Hydrochloride Solution by a Vesicle Surfactant.

Nicotine hydrochloride (NCT) has a good control effect on hemiptera pests, but its poor interfacial behavior on the hydrophobic leaf leads to few practical applications. In this study, a vesicle solution by the eco-friendly surfactant, sodium diisooctyl succinate sulfonate (AOT), was prepared as the pesticide carrier for NCT. The physical chemical properties of NCT-loaded AOT vesicles (NCT/AOT) were investigated by techniques such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). The results showed that the pesticide loading and encapsulation efficiency of NCT/AOT were 10.6% and 94.8%, respectively. The size of NCT/AOT vesicle was about 177 nm. SAXS and surface tension results indicated that the structure of the NCT/AOT vesicle still existed with low surface tension even after being diluted 200 times. The contact angle of NCT/AOT was always below 30°, which means it could wet the surface of the cabbage leaf well. Consequently, NCT/AOT vesicles could effectively reduce the bounce of pesticide droplets. In vitro release experiments showed that NCT/AOT vesicles had sustained release properties; 60% of NCT in NCT/AOT released after 24 h, and 80% after 48 h. Insecticidal activity assays against aphids revealed that AOT vesicles exhibited insecticidal activity and could have a synergistic insecticidal effect with NCT after the loading of NCT. Thus, the NCT/AOT vesicles significantly improved the insecticidal efficiency of NCT, which has potential application in agricultural production activities.

Mitochondria-specific peptide amphiphiles induce mitochondrial dysfunction and peripheral T-cell lymphomas (PTCL) damage.

Background: Peripheral T-cell lymphomas (PTCL) are aggressive lymphomas with poor prognosis, and therefore, there is a pressing need to explore new targets or compounds. Mitochondria may serve as a potential therapeutic target for PTCL. A designed positively-charged segment (pKV) is anchored to the specific 15 amino acid sequence (MIASHLLAYFFTELN) to yield a cell-penetrating peptide (pHK-pKV) and a lipid chain (Pal) is conjugated to the N-terminus of pHK-pKV (Pal-pHK-pKV) are bioactive amphiphilic peptide assemblies targeting the interaction between mitochondrial voltage dependent anion channel 1 (VDAC1) and hexokinase II (HKII). Methods: PTCL cell line H9 was treated with Pal-pHK-pKV and pHK-pKV, respectively. Cell proliferation in each group was measured by detecting cell viability and the corresponding marker Ki-67. Apoptosis was detected by immunofluorescence, flow cytometry and western blot. We also measured mitochondrial membrane potential, adenosine triphosphate (ATP) production, the cytochrome c distribution and the expression levels of B cell lymphoma 2 (BCL-2) and BCL-2 associated X protein (BAX). Western blot was used to detect the activation of the extracellular regulated protein kinases (ERK) signaling pathway. Results: Pal-pHK-pKV and pHK-pKV with 20 µM blocked the interaction between VDAC1 and HKII, and detached HKII from mitochondria, which depolarized the mitochondrial membrane potential, induced mitochondria dysfunction, and decreased ATP production. The decreased ATP subsequently inhibited the activation of the ERK/BCL-2 pathway and increased the BAX/BCL-2 ratio. Cytochrome c was then released from the mitochondria and induced capase-3 activation and subsequently apoptosis. Additionally, decreased ATP induced the expression of FAS and then apoptosis. Conclusions: Mitochondria specific peptide amphiphiles induce mitochondrial dysfunction and provide a new approach for the treatment of PTCL.

Mitochondrial Voltage-Dependent Anion Channel 1-Hexokinase-II Complex-Targeted Strategy for Melanoma Inhibition Using Designed Multiblock Peptide Amphiphiles.

Targeted therapies of melanoma are of urgent need considering the resistance of this aggressive type of cancer to chemotherapeutics. The voltage-dependent anion channel 1 (VDAC1)-hexokinase-II (HK-II) complex is an emerging target for novel anticancer therapies based on induced mitochondria-mediated apoptosis. The low cell membrane permeability of the anticancer 12-mer peptide N-Ter (RDVFTKGYGFGL) derived from the N-terminal fragment of the VDAC1 protein impedes the intracellular targeting. Here, novel multiblock VDAC1-derived cationic amphiphilic peptides (referred to as Pal-N-Ter-TAT, pFL-N-Ter-TAT, and Pal-pFL-N-Ter-TAT) are designed with a self-assembly propensity and cell-penetrating properties. The created multiblock amphiphilic peptides of partial α-helical conformations form nanoparticles of ellipsoid-like shapes and are characterized by enhanced cellular uptake. The amphiphilic peptides can target mitochondria and dissociate the VDAC1-HK-II complex at the outer mitochondrial membrane, which result in mitochondria-mediated apoptosis. The latter is associated with decrease of the mitochondrial membrane potential, cytochrome c release, and changes of the expression levels of the apoptotic proteins in A375 melanoma cells. Importantly, the mitochondrial VDAC1-derived amphiphilic peptides have a comparable IC50 value for melanoma cells to a small-molecule drug, sorafenib, which has been previously used in clinical trials for melanoma. These results demonstrate the potential of the designed peptide constructs for efficient melanoma inhibition.

A Lipidated Peptide with Mitochondrial Membrane Localization in Human A549 Lung Cells: From Enhanced Cell-Penetrating Properties to Biological Activity Mechanism.

Here, a lipidated peptide Pal-pHK-pKV with self-assembly properties and the ability to provoke the disruption of the mitochondrial voltage-dependent anion channel-1 protein (VDAC1)-hexokinase-II (HK-II) complex is reported. The effects of the peptide pHK (N-terminal 15-amino acid fragment of HK-II that specifically binds VDAC1) are compared to those of a designed biomimetic amphiphilic pHK-pKV conjugate (pHK coupled with a cell-penetrating peptide pKV) and Pal-pHK-pKV (a lipidated conjugate modified with a hydrophobic palmitic (Pal) alkyl chain). The Pal-pHK-pKV exhibits a stronger interaction with the membrane as compared to pHK-pKV, which is demonstrated by the Langmuir-Blodgett technique and two-photon excitation microscopy. The amphiphilic peptide derivatives are cytotoxic to the A549 cells, but Pal-pHK-pKV is more cytotoxic. The inhibitory effects of the pHK derivatives on the A549 cells growth are investigated through induced apoptosis pathway, depolarized mitochondrial membrane potential, inhibited glycolysis, and activated caspase. The results of the immunofluorescence evidence the specific mitochondrial targeting by those derivatives.

Construction and characterization of a temperature-responsive nanocarrier for imidacloprid based on mesoporous silica nanoparticles.

Nanopesticides have great potential applications due to their stability enhancement, sustained release and target affinity. In this work, a temperature-responsive nanocarrier for imidacloprid (IMI) was constructed using mesoporous silica nanoparticles (MSNs) as the core and paraffin wax (PW) as the outer layer. IMI was loaded into MSNs by screening the drug/carrier mass ratios to obtain the optimized IMI/MSNs formulation with a high drug loading (27.47 %). IMI/MSNs were functionalized with octadecyltrimethoxysilane (C18TMS) and further coated with a temperature-responsive trigger (PW) through hydrophobic interactions. Thus, a temperature-responsive nanocarrier for IMI (PW/IMI/MSNs) was constructed. Fourier transforms infrared (FT-IR), thermogravimetric analysis (TGA) and N2 adsorption-desorption isotherm measurements confirmed the successful loading of IMI into MSNs and the coating of PW on the surface of the IMI/MSNs. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses indicated that PW/IMI/MSNs with diameters approximately 100 nm had an ordered hexagonal mesoporous structure with a surface coating of approximately 6 nm. In addition, an in vitro release experiment showed that PW/IMI/MSNs displayed a temperature-responsive sustained release property. Correspondingly, the bioactivity assay of the PW/IMI/MSNs showed that the insecticidal activity greatly increased with temperature. This formulation is expected to have potential applications in some high-temperature areas, such as Turpan in Xinjiang Province, for improving the utilization efficiency of IMI.

Eco-friendly Water-Based λ-Cyhalothrin Polydopamine Microcapsule Suspension with High Adhesion on Leaf for Reducing Pesticides Loss.

Recently, innovations of nano/microcarrier formulations have been focused on improving application efficiencies and retention time. In this study, a water-based 2.5% λ-cyhalothrin (LC) microcapsule suspension (CS) was developed by orthogonal test with biodegradable and adhesive polydopamine (PDA) microcapsules (MCs) as carriers. The obtained LC-PDA CS had good suspension properties, flow behavior, storage stability, and rheological properties. LC-PDA CS had higher retention, wettability, and decreased rainwater washing out on the leaves than commercial CS. LC-PDA CS displayed higher insecticidal activity against Lipaphis erysimi compared to commercial CS. LC-PDA CS reduced the toxicity of LC to the aquatic organism Danio rerio compared to LC. The above results demonstrated that LC-PDA CS would be eco-friendly water-based pesticides carrier system for prolonging the retention time on target leaf and reducing toxicity to aquatic organisms.

Application of N-methyl-D-aspartate receptor nanopore in screening ligand molecules.

N-methyl-D-aspartate receptors (NMDARs) are crucial for excitatory synaptic transmission in the central nervous system. To study NMDARs more accurately and conveniently, we developed a stable NMDAR nanopore in a planar lipid bilayer. Pharmacological properties were validated using the allosteric modulator Ro 25-6981 and antagonist D-2-amino-5-phosphonopentanoic acid (D-APV). The cyanotoxin ß-N-methylamino-L-alanine (BMAA) found in fresh water systems is suspected to be associated with the development of neurodegenerative diseases. Therefore, BMAA and its two isomers L-2, 4-Diaminobutyric acid dihydrochloride (DAB) and N-(2-aminoethyl) glycine (AEG) and an endogenous excitotoxin, quinolinic acid (QA), were studied using the NMDAR nanopores to assess their effects on NMDAR modulation. We demonstrated that the NMDAR nanopore could reliably detect its ligand molecules at the single-channel level. The study also demonstrated the practicability of NMDAR nanopores, and results were validated using two-electrode voltage-clamp (TEVC) recording. Compared with TEVC recording, the NMDAR nanopores conducted ion channel gating at the single-channel level without being affected by other proteins on the cell membrane. The highly sensitive and accurate NMDAR nanopore technique thus has a unique advantage in screening NMDAR ligand molecules that could be associated with neurodegenerative disease.

Single-Molecule Study of Peptides with the Same Amino Acid Composition but Different Sequences by Using an Aerolysin Nanopore.

Nanopores are original sensors employed for highly sensitive peptides/proteins detection. Herein, we describe the use of an aerolysin nanopore to identify two similar model peptides, YEQYEQQDDDRQQQ (YEQ2Q3) and QDDDRQQQYEQYEQ (Q3YEQ2), with the same amino acid composition but different sequences. All-atom molecular dynamics (MD) simulations reveal that YEQ2Q3 possesses fewer hydrogen bonds and a more extended conformation than Q3YEQ2. These two peptides, which fold differently, exhibit obviously distinct mass-independent current blockades with characteristic dwell times when entering the aerolysin nanopore. Typically, at +60 mV, the statistical dwell time of 0.630±0.018 ms for peptide Q3YEQ2 is four times longer than the value of 0.160±0.001 ms for peptide YEQ2Q3, and yet peptide YEQ2Q3 induces ∼1.9 % larger blockade current amplitude than peptide Q3YEQ2. The obtained results show the remarkable potential of aerolysin nanopore for peptides/proteins identification, characterization, sequencing and also demonstrate that the mass identification of nonuniformly charged peptides/proteins by using the nanopore technique could be complicated by their folded structure and complex analyte-pore interaction.

pH Responsiveness of Hexosomes and Cubosomes for Combined Delivery of Brucea javanica Oil and Doxorubicin.

We report pH-responsive liquid crystalline lipid nanoparticles, which are dual-loaded by Brucea javanica oil (BJO) and doxorubicin hydrochloride (DOX) and display a pH-induced inverted hexagonal (pH = 7.4) to cubic (pH = 6.8) to emulsified microemulsion (pH = 5.3) phase transition with a therapeutic application in cancer inhibition. BJO is a traditional herbal medicine that strongly inhibits the proliferation and metastasis of various cancers. Doxorubicin is an antitumor drug, which prevents DNA replication and hampers protein synthesis through intercalation between the base pairs of the DNA helices. Its dose-dependent cardiotoxicity imposes the need for safe delivery carriers. Here, pH-induced changes in the structural and interfacial properties of designed multicomponent drug delivery (monoolein-oleic acid-BJO-DOX) systems are determined by synchrotron small-angle X-ray scattering and the Langmuir film balance technique. The nanocarrier assemblies display good physical stability in the studied pH range and adequate particle sizes and ζ-potentials. Their interaction with model lipid membrane interfaces is enhanced under acidic pH conditions, which mimic the microenvironment around tumor cells. In vitro cytotoxicity and apoptosis studies with BJO-DOX dual-loaded pH-switchable liquid crystalline nanoparticles are performed on the human breast cancer Michigan Cancer Foundation-7 (MCF-7) cell line and MCF-7 cells with doxorubicin resistance (MCF-7/DOX), respectively. The obtained pH-sensitive nanomedicines exhibit enhanced antitumor efficacy. The performed preliminary studies suggest a potential reversal of the resistance of the MCF-7/DOX cells to DOX. These results highlight the necessity for further understanding the link between the established pH-dependent drug release profiles of the nanocarriers and the role of their pH-switchable inverted hexagonal, bicontinuous cubic, and emulsified microemulsion inner organizations for therapeutic outcomes.

Self-assembly of mitochondria-specific peptide amphiphiles amplifying lung cancer cell death through targeting the VDAC1-hexokinase-II complex.

Mitochondria-targeting peptides represent an emergent tool for cancer inhibition. Here supramolecular assemblies of novel amphiphilic cell-penetrating peptides for targeting cancer cell mitochondria are reported. The employed strategy aims at amplifying the apoptotic stimuli by weakening the mitochondrial VDAC1 (voltage-dependent anion channel-1)-hexokinase-II (HK-II) interaction. Peptide engineering is performed with the N-terminus of the HK-II protein, which binds to VDAC1. First, a designed positively charged segment (pKV) is anchored to the specific 15 amino acid sequence (MIASHLLAYFFTELN) to yield a cell-penetrating peptide (pHK-pKV). Second, a lipid chain (Pal) is conjugated to the N-terminus of pHK-pKV in order to enhance the intracellular delivery of the HK-II scaffold. The self-assembly properties of these two synthetic peptides are investigated by synchrotron small-angle X-ray scattering (BioSAXS) and cryogenic transmission electron (cryo-TEM) imaging, which evidence the formation of nanoassemblies of ellipsoid-like shapes. Circular dichroism (CD) spectroscopy demonstrates the induction of partial α-helical structures in the amphiphilic peptides. Confocal microscopy reveals the specific mitochondrial location of Pal-pHK-pKV assemblies in human non-small cell lung cancer (NSCLC) A549 cells. The cytotoxicity and apoptotic studies indicate the enhanced bioactivity of Pal-pHK-pKV self-assembled reservoirs, which cause massive A549 cell death with regard to pHK-pKV. Of significance, Pal-pHK-pKV treatment of non-cancerous NCM460 cells resulted in substantially lower cytotoxicity. The results demonstrate the potential of self-assembled lipo-peptide (HK-II-derived) conjugates as a promising strategy in cancer therapy.

In situ phase transition of microemulsions for parenteral injection yielding lyotropic liquid crystalline carriers of the antitumor drug bufalin.

In this work, we used the small angle X-ray scattering (SAXS) method for controlled preparation of in situ forming sustained-release carriers for the antitumor drug bufalin (BUF), which has very poor solubility and a considerable cardiotoxicity in a non-encapsulated state. To that aim, we exploited the pseudo-ternary phase diagram of an oil(O)/surfactant(S)/water(W) system containing medium chain capric/caprylic triglycerides (MCT) and a co-surfactant blend of Macrogol (15)-hydroxystearate (Solutol HS 15) and sorbitan monooleate (Span 80). Two compositions with different oil contents (sample B and C) were selected from the microemulsion region of the phase diagram in order to study the effect of the aqueous environment on their structural behavior. A phase transition from a microemulsion (ME) to a liquid crystalline phase (LC) was established by SAXS upon progressive dilution. The drug bufalin (BUF) was encapsulated in the microemulsions with low viscosity, whereas the release of the drug occurred from the in situ generated lamellar liquid crystalline structures. The formulations were characterized by SAXS, dynamic light scattering (DLS), cryogenic transmission electron microscopy (Cryo-TEM), rheology, drug loading and encapsulation efficiency, and in vitro release profiles. A correlation was suggested between the structures of the in situ phase-transition formed LCME formulations, the differences in their viscosities and drug release profiles. The performed cytotoxicity, cell apoptosis and pharmacokinetic experiments showed an enhanced bioavailability of BUF after encapsulation. These results suggest potential clinical applications for the obtained safe in situ phase-transition sustained-release formulations of BUF.

Construction and Characterization of a Novel Sustained-Release Delivery System for Hydrophobic Pesticides Using Biodegradable Polydopamine-Based Microcapsules.

Microcapsule formulations have been highly desirable and widely developed for effective utilization of pesticides and environmental pollution reduction. However, commercial and traditional microcapsule formulations of λ-cyhalothrin (LC) were prepared by complicated synthesis procedures and thereby specific organic solvents were needed. In this work, LC was encapsulated into versatile, robust, and biodegradable polydopamine (PDA) microcapsules by self-polymerization of dopamine. LC-loaded PDA microcapsules were characterized by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and thermogravimetric analysis measurements (TGA). LC-loaded PDA microcapsules have uniform morphology with nanoscale, decent LC loading content (>50.0% w/w), and good physicochemical stability and sustained release properties. The bioassay against housefly ( Musca domestica) showed that the bioactivity and long-term efficiency of LC-loaded PDA microcapsules was superior to that of the commercial formulation. All of these results demonstrated that LC-loaded PDA microcapsules could be applied as a commercial LC microcapsule formulation with fewer environmental side effects and higher effective delivery.

Preparation of an Environmentally Friendly Formulation of the Insecticide Nicotine Hydrochloride through Encapsulation in Chitosan/Tripolyphosphate Nanoparticles.

Insecticide nicotine hydrochloride (NCT) was formulated as nanoparticles composed of chitosan (CS) and sodium tripolyphosphate (TPP) to undermine its adverse impacts on human health and reinforce its physicochemical stability. The study investigated the preparation and characterization of chitosan/tripolyphosphate nanoparticles (CS/TPP NPs) with good encapsulation efficiency (55%), uniform morphology, and physicochemical stability (45 days) through dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS) measurements. A bioassay against Musca domestica NCT CS/TPP NPs exhibited good bioactivity and thermal stability. The effect of the monovalent salt (NaCl) on manipulating the formation and size distribution of ionically cross-linked nanoparticles was demonstrated as well. The formulation of NCT CS/TPP NPs could be a utility candidate in public health and agriculture.

Reversible switching of a supramolecular morphology driven by an amphiphilic bistable [2]rotaxane.

An acid/base responsive amphiphilic [2]rotaxane switch containing a hydrophilic macrocycle component and a hydrophobic terminal bulky group was prepared and characterized. The morphology of the supramolecular assemblies formed by the rotaxanes could be switched between spherical vesicles and worm-like micelles using acid/base stimuli, as confirmed by transmission electron microscopy (TEM).

Folate receptor targeted bufalin/ß-cyclodextrin supramolecular inclusion complex for enhanced solubility and anti-tumor efficiency of bufalin.

Bufalin (BF), a traditional Chinese medicine, exhibited inhibitory activities against a broad spectrum of tumor cells. The present study elaborates that bufalin was successfully encapsulated into the cavity of ß-cyclodextrin (ß-CD), which was determined by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The best reaction mole ratio of BF/ß-CD was 1:5. The solubilities of bufalin in water and phosphate buffer solution (pH=7.4) were increased up to 24 and 34 times after encapsulated into the cavity of ß-CD respectively. The inclusion efficiency (IE) and drug loading (DL) of bufalin in the inclusion complex were (94.22±0.85)% and (14.11±0.20)%, respectively. Then ß-CD conjugated with folic acid (FA) were further prepared and employed to improve the anti-tumor efficacy of inclusion complex. The in vitro dissolution and solubility study showed better values of inclusion complex and FA targeted inclusion complex than that of pure BF. Cytotoxicity experiments by using HCT116 cell line revealed that the antitumor efficiency of bufalin were enhanced more than two folds in the presence of ß-CD and folate conjugated ß-CD (FA-PEI-ß-CD), which demonstrated the potential application of ß-CD (FA-PEI-ß-CD) as delivery vehicles of bufalin for antitumor therapy.