Enzyme/pH dual-stimuli responsive prochloraz nanopesticide controlled release system for kiwifruit soft rot disease control.

Spodoptera frugiperda is a global pest that brings about great disasters to crops. Conventional pesticide formulations often suffer from poor water solubility, low stability, burst release, weak leaf adhesion, and low efficiency. To improve the insecticidal activity of pesticides, a stimuli-responsive controlled release pesticide delivery system (PDS) has attracted extensive attention in recent years. This paper reports a temperature-responsive controlled release PDS based on poly(N-isopropyl acrylamide) (PNIPAm)-modified indoxacarb (IDC)-loaded UiO-66-(COOH)2 (IDC@UiO-66-(COOH)2-PNIPAm) and studies its insecticidal activities against S. frugiperda. The UiO-66-(COOH)2 nanocarrier has an excellent pesticide loading performance, and the loading rate for IDC is 78.69%. The as-prepared PDS has good stability, temperature-responsive controllable release performance, and enhanced leaf affinity, so it can effectively improve the utilization rate of IDC. The insecticidal experiment indicates that the PDS has an enhanced control effect against S. frugiperda. In addition, biosafety analysis further verifies that the PDS exhibits no obvious negative effects on the germination of maize seeds and the growth of maize seedlings. In view of this, we believe that this PDS will have a broad application in the field of pesticide formulation innovation, pest management, and sustainable agricultural development.

Mesoporous silica nanoparticle has been garnering a lot of attention as a drug carrier in drug delivery systems due to their unique physiochemical properties, including high surface area, tunable pore structure, high pore volume and their excellent biocompatibility. Despite the advantages, ensuring the drugs are carried to the targeted areas can be a challenge. Hence, a pH-responsive gatekeeper namely chitosan, was used for the surface modification of mesoporous silica nanoparticle. In this study, via the sol-gel method, mesoporous silica nanoparticle was synthesised, and chlorhexidine was loaded into the pores of mesoporous silica nanoparticle. Further coating of mesoporous silica nanoparticle with chitosan conjugated ibuprofen was done to enable the dual drug loading and pH sensitive release. To confirm the loading and the coating on the surface of mesoporous silica nanoparticle, FTIR and TEM was used. The drug release was also studied in-vitro in controlled release behaviour under acidic conditions, mimicking the oral disease environment as well as in neutral conditions as a comparison for when the oral cavity is healthy. At pH 4.5, the maximum release reached 41.0% for CHX and 10.5% for IBP, compared to 30.4% and 7.4% respectively, at neutral pH. The findings suggests that MSN/CHX-CHI/IBP is promising for dual delivery in dental applications, demonstrating pH-responsive behavior with significantly higher release under acidic conditions.

Core-shell structure is a concentric circle structure found in nature. The rapid development of electrospinning technology provides more approaches for the production of core-shell nanofibers. The nanoscale effects and expansive specific surface area of core-shell nanofibers can facilitate the dissolution of drugs. By employing ingenious structural designs and judicious polymer selection, specialized nanofiber drug delivery systems can be prepared to achieve controlled drug release. The synergistic combination of core-shell structure and materials exhibits a strong strategy for enhancing the drug utilization efficiency and customizing the release profile of drugs. Consequently, multi-chamber core-shell nanofibers hold great promise for highly efficient disease treatment. However, little attention concentration is focused on the effect of multi-chamber core-shell nanofibers on controlled release of drugs. In this review, we introduced different fabrication techniques for multi-chamber core-shell nanostructures, including advanced electrospinning technologies and surface functionalization. Subsequently, we reviewed the different controlled drug release behaviors of multi-chamber core-shell nanofibers and their potential needs for disease treatment. The comprehensive elucidation of controlled release behaviors based on electrospun multi-chamber core-shell nanostructures could inspire the exploration of novel controlled delivery systems. Furthermore, once these fibers with customizable drug release profiles move toward industrial mass production, they will potentially promote the development of pharmacy and the treatment of various diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Photo-induced surface grafting of phosphorylcholine containing copolymers onto mesoporous silica nanoparticles for controlled drug delivery

Deterioration of fruits may take place after harvest in any stage, viz. storage, transit and during handling processes to move the produce from the farmers' field to the wholesaler and to retailer and finally to the consumer. These processes are responsible for enormous qualitative and quantitative losses of fruits in the market. Different types of fungal forms are found to be associated with and responsible for postharvest diseases of fruits during storage. Protection and proper handling measures of fresh fruits are not maintained in developing countries, so the losses during transit and storage are more than 50% of the harvested crop. Soft rot (Pestalotiopsis mangiferae, Phomopsis sapotae), basal rot (Ceratocystis paradoxa) and heart rot (Phytophthora parasitica, Alternaria alternata) are the common postharvest fungal diseases of sapota fruits, whereas in aonla, rust (Ravenelia emblicae Sydow, Phakopsora phyllanthi), anthracnose (Colletotrichum gloeosporioides (Glomerella cingulata), soft rot (Phomopsis phyllanthi Punith), sooty mould (Capnodium sp.), blue mould (Penicillium citrinum, P. expansum) and black soft rot (Syncephalastrum racemosum) are major postharvest diseases. Custard apple fruits suffer postharvest diseases like fruit rot/anthracnose (Colletotrichum gloeosporioides), Diplodia rot (Botryodiplodia theobromae) and black canker (Phomopsis annonacearum) and purple blotch/fruit rot (Phytophthora capsici) during storage and transportation.

Fluorescence-incorporated, crosslinker-free, pH- and thermoresponsive nanocarriers were prepared by the incorporation of drug molecules into the thermoresponsive nanocapsules, which composed of poly(N-isopropylacrylamide) (PNIPAAm) with carboxylic acid end groups via temperature induced self-assembling method. Well-defined, pH-responsive carboxylic acid group-ended PNIPAAm homopolymer (HOOCPNIPAAmCOOH) was synthesized by reversible addition fragmentation chain transfer polymerization with S,S′-bis(α,α′-dimethyl-α″-acetic acid)trithiocarbonate (CMP) as a chain transfer agent. Rhodamine 6G (R6G), the model drug, was used for three kinds of application: First, the nanostructure fixing; second, the fluorescence-labeling; and last, the controlled release modeling. The transmission electron microscope images showed the solution type dosing led to the encapsulation of drug molecules into the nanocarriers, while the powder-type drug-loading process significantly contributed to the structure preservation of nanocarriers. The controlled release behaviors with various pH values and temperatures were evaluated. These multifunctional nanocarriers have potential to be applied for the biomedical therapy by stimuli-responsive controlled release. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 561–571

A nanotheranostic system is a new system that combines both diagnosis and treatment of a malignant disease, e.g. cancer, by exploitation of the unusual properties of nano-sized particles. In this project, we have developed a novel nanotheranostic system based on quantum dots (QDs) coated with drug-loaded polymer. We first synthesized a double-group functionalized amphiphilic triblock copolymer and loaded it with the anti-tumour drug paclitaxel (PTX) and lipoic acid (LA) to obtain the prodrug mPEG-block-PCL-(graft-PTX)-block-PLA-(graft-LA) (mPEG: methoxy polyethylene glycol, PLA: poly(norbornene-lactide)s). When exposed to UV light (365 nm), the disulfide bond of LA was broken into two sulfydryls, which could in turn adhere to the surface of CdSe/ZnS QDs to form a nanotheranostic system. This novel system exhibited good controlled drug release behaviour due to the ester linkage between the drug and polymer. By using typical cancer cell lines, we showed that this nanotheranostic system is promising in cancer diagnosis and treatment in vitro.

In this research, a novel tumor targeting dual stimuli responsive nanoplatform was fabricated for the controllable delivery and release of a drug to realize chemo-photothermal synergetic cancer therapy by integrating a DNA aptamer with polydopamine reduced graphene oxide (rGO-PDA) nanosheets. The rGO-PDA nanosheets simultaneously acted as a near-infrared radiation (NIR) photothermal agent to generate hyperthermia for photothermal therapy and a nano-carrier for loading doxorubicin (DOX), and the specially designed DNA aptamer served as a supplementary carrier for DOX loading as well as targeting moiety/gatekeeper for specific cellular recognition and controllable release of DOX. The proposed nanoplatform possessed a good targeting ability, remarkable photothermal conversion ability and intelligent drug release with both pH and photothermal heating dual stimuli response. The nanoplatform was successfully used to selectively deliver DOX to protein tyrosine kinase 7 over-expressing cancer cells with a loading capacity of 1.56 mg mg-1 and controllable drug release, which responded to both acidic intracellular environments and NIR irradiation. The combination of the dual stimuli responsive controllable release and the dual nanocarrier for drug loading results in efficient chemo-photothermal synergetic therapy and holds great potential for multimodal cancer therapy.

Antifungal activity of natamycin against kiwifruit soft rot caused by Botryosphaeria dothidea and potential mechanisms

Guiding mesenchymal stem cell differentiation using mesoporous silica nanoparticle-based films

Traditional pesticides suffer from low utilization rates, poor photodegradability, and environmental pollution issues. Developing highly efficient and environmentally friendly pesticide delivery systems is of paramount importance. This study utilized zein-sodium caseinate (Zein-NaCas) composite nanoparticles as stabilizers with ethyl acetate (EA) and soybean oil (SO) as the oil phase. Without the addition of toxic surfactants, the hydrophobic pesticide avermectin-loaded Pickering emulsion (AVM@PK) was prepared. Zein-NaCas solid particles were formed through hydrophilic–hydrophobic interactions and can adsorb at the oil–water interface to form a boundary film, thereby preventing droplet coalescence. By optimizing the solid particle concentration and oil phase volume fraction, this system maintains excellent emulsion stability. Compared with AVM-commercial emulsified oil (AVM-EC), this emulsion exhibits 2.1-fold enhanced photodegradation resistance. In vitro release experiments indicate that glutathione (GSH) degradation rapidly destabilizes the emulsion, leading to accelerated avermectin (AVM) release. Bioactivity tests demonstrate that the emulsion exhibits higher lethality and lower LC50 values against lepidoptera insects. This study provides a novel strategy for constructing green pesticide delivery systems and achieving efficient encapsulation and slow release of hydrophobic pesticides.

Controlled stimuli-responsive release systems are a feasible and effective way to increase the efficiency of pesticides and help improve environmental pollution issues. However, near-infrared (NIR)-responsive systems for encapsulation of pesticides for controlling release have not been reported because of high cost and load ability of conventional NIR absorbers as well as complicated preparation process. Herein, we proposed polydopamine (PDA) microspheres as a photothermal agent owing to their abundant active sites, satisfactory photothermal efficiency, low cost, and easy fabrication, followed by capping with a PNIPAm thermosensitive polymer shell. In this core-shell PDA@PNIPAm hybrid system, the PDA core provided excellent temperature and NIR-light sensitivity as well as high loading capacity, while the PNIPAm applied as both a thermosensitive gatekeeper and a pesticide reservoir. The structure of the PDA@PNIPAm nanocomposites was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, dynamic light scattering, and thermogravimetric analysis; the results showed that the nanocomposites had a well-defined core-shell configuration for efficient loading of small pesticide molecules. Moreover, the core-shell PDA@PNIPAm nanocomposites exhibited high loading capacity and temperature- or NIR-controlled release performance. Overall, this system has significant potential in controlled drug release and agriculture-related fields as a delivery system for pesticides with photothermal responsive behavior.

Carrot is an important root vegetable which plays an important role in human health. Globally, Post harvest diseases are the major constraint in carrot production, especially soft rot which resulting in severe yield loss. Early diagnosis of these post-harvest diseases paves a way for reducing the economic losses. Carrot samples showing typical rotting symptoms were collected from markets of four different districts of Tamil Nadu and the pathogen involved were isolated. Severe carrot soft rot incidence (66.74%) was observed in samples collected from Ooty area of The Nilgiris district and the least disease incidence of (16.21%) was recorded in Perundurai of Erode district. Pathogenicity of soft rot pathogen were conducted and the virulent isolates were identified based on Percent Disease Index (PDI) showing >50% rotting falls under disease grade 9 using disease grade scale (0 to 9). The bacterial isolates (KPB-7 and OCB-5) causing soft rot were characterized using various biochemical assays where in they showed positive response for methyl red, H2S gas production, KOH and catalase tests besides showing negative response for gram’s reaction. Furthermore, molecular characterization of 16s rRNA region revealed the soft rot isolate (KPB-7) as Pectobacterium carotovorum subsp carotovorum (with an accession number OR251119).

A pH-responsive charge-convertible drug delivery nanocarrier (MSN-TPZ-GOx@ZnO@PAH-PEG-DMMA, abbreviated as MTGZ@PPD) was prepared, which could specifically release hypoxia-activated chemotherapeutic Tirapazamine (TPZ) and glucose oxidase (GOx) in the tumor site for precise starvation and chemo synergistic oncotherapy. Acid-responsive Schiff base structure modified mesoporous silica nanoparticles (MSN) co-load with GOx and TPZ, then link with ZnO quantum dots (QDs). PAH-PEG-DMMA (PPD) polymer makes MTGZ@PPD with biocompatibility and charge-convertible feature. MTGZ@PPD is negatively charged at physiological pH, and the charge reversal of PPD and acidolysis of the Schiff base structure under the acidic tumor microenvironment (TME) induce a positively charged surface, which could potentiate the cell internalization. ZnO QDs could decompose at acidic TME, achieving controllable drug release. GOx could starve the tumor cells and enhance hypoxia level, thus initiates the activation of TPZ to realize synergistic starvation therapy and chemotherapy. This intelligent MTGZ@PPD has shown great potential for starvation and chemo synergistic oncotherapy.

Ultrasmall Ag clusters in situ encapsulated into Silicalite-1 zeolite with controlled release behavior and enhanced antibacterial activity