Core–shell particles for controllable release of drug

Tunable NPK Release from Surface-Esterified Nanocellulose-Based Prills

Polysaccharides represent an ideal delivery platform for agrochemicals due to their biodegradability, biocompatibility, and abundance. However, hydrophilicity renders native polysaccharides ineffective at controlling the release of water-soluble agrochemicals. To overcome this limitation, we used a solvent-free, vapor-phase modification strategy to generate hydrophobic shells on the surface of nanofibrillated cellulose (CNF) prills and evaluated the effects of these tunable diffusion barriers on fertilizer release behavior. Hydrophobic shells of different thicknesses were created on CNF prills by esterification with acyl chlorides of varying alkyl chain lengths, although esterification did not hinder the inherent biodegradability of the CNFs. Fertilizer release rates were largely invariable to pH and NPK loading but were tunable over 3 orders of magnitude by varying the alkyl chain length and the degree of substitution (i.e., shell thickness). However, NPK release rates did not increase monotonically with increasing shell thickness; for long-chain (6 carbons or longer) esters, increases in shell thickness beyond optimal values increased release rates; SEM revealed that this originated from the introduction of fractures to the prills which act as diffusion channels. This work demonstrates the potential of controlled surface modification to generate a mineralizable and tunable NPK release platform from naturally sourced and sustainable feedstocks.

Developing Eco-Friendly, High-Performance Soy Protein Plywood Adhesive via Core-Shell Hybridization and Borate Chemistry

Developing eco-friendly, high-performance adhesives is crucial for sustainable industrial applications but remains a significant challenge. Herein, a synergistic strategy combining core-shell hybridization and borate chemistry was employed to fabricate a multifunctional soy protein (SPI) adhesive with excellent adhesion. Specifically, a reactive core-shell hybrid (POSS-U) was synthesized via free-radical polymerization using octavinyl-POSS as the core and urushiol (U) as the shell. Sodium borate (SB) was then added as a crosslinker, along with POSS-U and SPI, to prepare the SPI/POSS-U/SB adhesive. The SPI/POSS-U/SB adhesive exhibited a 100% increase in dry shear strength (2.46 MPa) and a wet shear strength of 0.74 MPa, meeting indoor application standards. Due to the thermal shielding and char formation of POSS and SB, the peak heat release rate of the modified adhesive reduced by 25.4%, revealing excellent flame retardancy. Additionally, the modified adhesive remained mold-free for 144 h due to the antifungal properties of urushiol and boron. This work provides an innovative approach for enhancing protein-based adhesives and contributes to the advancement of multifunctional composite materials.

A poly (vinyl alcohol) coated core-shell nanoparticle with a tunable surface for pH and glutathione dual-responsive drug delivery

The surface characteristics of nanoparticles play a pivotal role in modulating the efficiency and functionality of drug delivery systems, particularly when addressing the complex challenges of targeted therapeutics. This study presents the development of a core-shell nanoparticle system (PMAA@DOX-PVA), incorporating poly(vinyl alcohol) (PVA) as a dynamic shell component to establish dual responsiveness to pH and glutathione levels. The hydrophilic PVA shell is covalently conjugated to the poly (methylacrylic acid) (PMAA) core via a boronic ester bond, establishing a robust platform for controlled release with tunable surface properties. Notably, our findings demonstrate a remarkable enhancement in drug loading efficiency from a modest 8 % (PMAA@DOX) to an impressive 18 % (PMAA@DOX-PVA-0.2). Furthermore, under physiological conditions (pH 7.4), the drug leakage after 62 hours is significantly reduced, dropping from 37 % (PMAA@DOX) to 21 % (PMAA@DOX-PVA-0.2). This suggests a potential improvement in stability during blood circulation. Intriguingly, the PVA ratio was found to influence drug release profiles under different environments distinctly. The possible mechanism was proposed offering insight into this tunable behavior. In vitro cytotoxicity assays on A549 cancer cells reveal that the blank carriers exhibit excellent biocompatibility, while the PVA-coated nanoparticles significantly boost anti-tumor efficacy. Collectively, these results present a promising strategy for designing core-shell nanoparticles with customizable surface properties, paving the way for next-generation, multifunctional drug delivery systems in diverse biomedical applications.

Microfluidic fabrication of rattle shaped biopolymer microcapsules via sequential phase separation in oil droplets

Multilayer microcapsules containing a small particle within a larger capsule have recently attracted considerable attention owing to their potential applications in diverse fields, including drug delivery, active ingredient storage, and chemical reactions. These complex capsules have been fabricated using interfacial polymerization or seeded emulsion polymerization. However, these methods often require complex and lengthy polymerization processes, limiting their utility, particularly in biopolymer systems. This study introduces a simple and efficient approach for preparing rattle-shaped cellulose acetate (CA) microcapsules through sequential phase separation in droplets. We systematically examine the effects of various preparation parameters, including the amount of co-solvent, initial droplet size, and flow rates, and reveal that the incorporation of a co-solvent-ethyl acetate (EA)- in the dispersed phase significantly impacts the microcapsule morphology. Our findings demonstrate a transition from a core-shell to a rattle-shaped structure as the EA concentration increases. Furthermore, the initial droplet diameter and flow rates influence microcapsule formation-larger droplets and reduced continuous-phase flow rates favor the development of multi-layered structures. These results indicate that the formation mechanism of these rattle-shaped microcapsules arises from the establishment of a radial solvent concentration gradient and subsequent phase separation within the droplets, driven by kinetic rather than thermodynamic factors.

Design and Synthesis of Cabazitaxel Loaded Core-Shell Mesoporous Silica Nanoparticles with Different Morphologies for Prostate Cancer Therapy

In this work, the synthesis of core-shell ordered mesoporous silica nanoparticles (CSMS) with tunable particle size and shape through a dual surfactant-assisted approach is demonstrated. By varying the synthesis conditions, including the type of the solvent and the concentration of the surfactant, monodispersed and ordered mesoporous silica nanoparticles with tunable particle size (140-600 nm) and morphologies (hexagonal prism (HP), oblong, spherical, and hollow-core) can be realized. Comparative studies of the Cabazitaxel (CBZ)-loaded HP and spherical-shaped CSMS are conducted to evaluate their drug delivery efficiency to PC3 (prostate cancer) cell lines. These nanoparticles showed good biocompatibility and displayed a faster drug release at acidic pH than at basic pH. The cellular uptake of CSMS measured using confocal microscopy, flow cytometry, microplate reader, and ICP-MS (inductively coupled plasma mass spectrometry) techniques in PC3 cell lines revealed a better uptake of CSMS with HP morphology than its spherical counterparts. Cytotoxicity study showed that the anticancer activity of CBZ is improved with a higher free radical production when loaded onto CSMS. These unique materials with tunable morphology can serve as an excellent drug delivery system and will have potential applications for treating various cancers.

Fabrication and application of carrier-free and carrier-based nanopesticides in pest management

Pesticides are widely used for pest control to promote sustained and stable growth of agricultural production. However, indiscriminate pesticide usage poses a great threat to environmental and human health. In recent years, nanotechnology has shown the ability to increase the performance of conventional pesticides and has great potential for improving adhesion to crop foliage, solubility, stability, targeted delivery, and so forth. This review discusses two types of nanopesticides, namely, carrier-free nanopesticides and carrier-based nanopesticides, that can precisely release necessary and sufficient amounts of active ingredients. At first, the basic characterization and preparation methods of these two distinct types of nanopesticides are briefly summarized. Subsequently, current applications and future perspectives on scientific examples and strategies for promoting the usage efficacy and reducing the environmental risks of these nanopesticides were also described. Overall, nanopesticides can promote higher crop yields and lay the foundation for sustainable agriculture and global food security.

Switchable surface and loading/release of target molecules in hierarchically porous PLA nonwovens based on shape memory effect

In this work, hierarchically porous PLA (polylactic acid) shape memory nonwovens were prepared by electrospinning its blend solution with PEO (polyethylene oxide) and subsequent water etching. Based on shape memory effect resulting from tiny crystals and the amorphous matrix of PLA, the switch between compact and porous surfaces has been achieved via cyclical hot-pressing and recovery in a hot water bath. After hot-pressing, the disappearance of hierarchical pores contributes to compact surface, enabling embedding of the target molecule in PLA nonwoven (i.e., CLOSE state). Upon exposure to heat, PLA nonwoven recovers to its permanent shape and exhibits a porous surface, providing a penetrative diffusion pathway for small molecules (i.e., OPEN state). The hierarchically porous structure and shape memory effect endow PLA nonwoven with the capability of rapid release. Our results provide a good candidate for some potential applications, such as temperature-controlled quick-release of catalysts and drugs.

Tailored Morphology in Polystyrene/Poly(lactic acid) Blend Particles: Solvent's Effect on Controlled Janus/Core-Shell Structures

Controlling the morphology of polymeric particles is vital for their diverse applications. In this study, we explored how solvent composition influences the morphology of poly(styrene)/poly(lactic acid) (PS/PLA) particles prepared via the emulsion solvent evaporation method. We used toluene, dichloromethane (DCM), and various mixtures to prepare these particles. We investigated phase separation within the PS/PLA/solvent system using the Flory-Huggins ternary phase diagram and MesoDyn simulation, revealing pronounced immiscibility and phase separation in both PS/PLA/DCM and PS/PLA/toluene systems. We employed scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to characterize the resulting morphologies. Our study unveiled the substantial impact of solvent composition on particle structure. Using pure toluene resulted in acorn-shaped Janus particles. However, incorporating DCM into the solvent induced a transition from Janus to core-shell morphology. Remarkably, core-shell particles exhibited a single-core structure in a mixed toluene/DCM solvent, indicating thermodynamic stability. In contrast, pure DCM favored kinetically controlled multicore morphology, leading to lower PLA crystallinity due to increased PS-PLA interfaces. Samples with high Janus balance formed a self-assembled, two-dimensional (2-D) monolayer film, demonstrating the interfacial activity of the Janus particles. This 2-D monolayer film exhibits desirable emulsification properties with potential applications in various fields. Our study combines theoretical and experimental analyses, shedding light on the profound impact of solvent composition on the PS/PLA particle morphology. We observed transitions from Janus to core-shell structures, highlighted the influence of solvent viscosity on particle size, and uncovered the formation of self-assembled 2-D monolayer films. These insights are pivotal for tailoring polymeric particle structures. Furthermore, our findings advance macromolecular science in interface design, offering promising prospects for innovative materials development.

Aligned core-shell fibrous nerve wrap containing Bletilla striata polysaccharide improves functional outcomes of peripheral nerve repair

Peripheral nerve injuries are commonly encountered in extremity traumas. Their motor and sensory recovery following microsurgical repair is limited by slow regeneration speed (<1 mm/d) and subsequent muscle atrophy, which are consequently correlated with the activity of local Schwann cells and efficacy of axon outgrowth. To promote post-surgical nerve regeneration, we synthesized a nerve wrap consisting of an aligned polycaprolactone (PCL) fiber shell with a Bletilla striata polysaccharide (BSP) core (APB). Cell experiments demonstrated that the APB nerve wrap markedly promoted neurite outgrowth and Schwann cell migration and proliferation. Animal experiments applying a rat sciatic nerve repair model indicated that the APB nerve wrap restored conduction efficacy of the repaired nerve and the compound action potential as well as contraction force of the related leg muscles. Histology of the downstream nerves disclosed significantly higher fascicle diameter and myelin thickness with the APB nerve wrap compared to those without BSP. Thus, the BSP-loaded nerve wrap is potentially beneficial for the functional recovery after peripheral nerve repair and offers sustained targeted release of a natural polysaccharide with good bioactivity.

Programmed pH-responsive core-shell nanoparticles for precisely targeted therapy of ulcerative colitis

pH-Responsive nanotherapeutics were recently developed for the treatment of ulcerative colitis (UC). However, they target the entire colon rather than the UC site, which leads to insufficient accumulation in inflamed colon lesions and causes side effects. Core-shell nanoparticles exhibit unique advantages in improving the precision of targeted delivery. In this study, Eudragit® EPO and L100, two pH-sensitive materials, were coated on nano-sized curcumin to fabricate core-shell nanoparticles. The developed CNs@EPO@L100 exhibited programmed pH-responsive drug release behavior, improved in vitro anti-inflammatory ability, and enhanced accumulation at the site of inflammation in the colon. Furthermore, after oral administration, CNs@EPO@L100 significantly ameliorated the inflammatory symptoms in mice. Taken together, this study provides insights into programmed release through the rational application of pH-sensitive materials and offers strategies for a precisely targeted therapy of UC using core-shell nanoparticles.

A flow map for core/shell microdroplet formation in the co-flow Microchannel using ternary phase-field numerical model

Core/shell microdroplets formation with uniform size is investigated numerically in the co-flow microchannel. The interface and volume fraction contour between three immiscible fluids are captured using a ternary phase-field model. Previous research has shown that the effective parameters of microdroplet size are the physical properties and velocity of the three phases. By adjusting these variables, five main flow patterns are observed in numerical simulations. A core/shell dripping/slug regime is observed when the inertia of the continuous phase breaks the flow of the core and shell phases and makes a droplet. In the slug regime, the continuous phase has less inertia, and the droplets that form are surrounded by the channel walls, while in the dripping regime, the shell phase fluid is surrounded by the continuous phase. An increase in continuous-fluid or shell-fluid flow rate leads to dripping to a jetting transition. When three immiscible liquids flow continuously and parallel to one another without dispersing, this is known as laminar flow. In the tubing regime, the core phase flows continuously in the channel's central region, the shell phase flows in the annulus formed by the core phase's central region, and the continuous phase flows between the shell phase fluid and channel walls. In order to discriminate between the aforementioned flow patterns using Weber and Capillary numbers and establish regime transition criteria based on these two dimensionless variables, a flow regime map is provided. Finally, a correlation for shell thickness using shell-to-core phase velocity ratio and conducting 51 CFD simulations was proposed.

Enhanced optical force on multilayered dielectric nanoparticles by tuning material properties and nature of excitation: a theoretical investigation

Using dipole approximation, a comparative study of trapping force/potential on different types of dielectric nanoparticles is presented. The trapping force for multilayered nanoparticles, i.e. core-shell-shell type nanoparticles, is found to be enhanced compared with both core-only type and core-shell type nanoparticles. It is shown that an appropriate choice of material and thickness of the middle layer results in tuning the polarizability, thereby playing a vital role in determining the trapping efficiency for core-shell-shell type nanoparticles. Further, the effect of optical nonlinearity under femtosecond pulsed excitation is investigated and it is elucidated that depending on the specific need (i.e. high force versus long confinement time), the nature of excitation (i.e. pulsed excitation or continuous-wave excitation) can be judiciously chosen. These findings are promised to open up new prospects for controlled nanoscale trapping and manipulation across different fields of nanoscience and nanotechnology.

Two birds with one stone: innovative ceria-loaded gold@platinum nanospheres for photothermal-catalytic therapy of tumors

Photothermal therapy (PTT) has been widely employed in tumor treatment due to the non-invasive, highly selective, and low toxic side effects. However, the limited penetration of laser couples with the metastasis and recurrence of tumors, thus failing to eliminate them. Here, we report that ceria-loaded gold@platinum (CeO₂/Au@Pt) nanospheres modified with polyethylene glycol (PEG). exhibit dual enzymatic activities for photothermal-catalytic synergistic therapy of tumors. CeO₂/Au@Pt nanospheres are constructed through the loading of ultra-small CeO₂ into core-shell Au@Pt nanospheres. In such a construct, Au@Pt enables targeted PTT, thanks to exceptional photothermal properties, while CeO₂ nanozymes alleviate tumor hypoxia and kill tumor cells by producing highly toxic hydroxyl radicals (·OH) based on catalase- and peroxidase-like activities. Synergistic photothermal-catalytic therapy is achieved by delivering nanozymes to the tumor microenvironment (TME) coupled with PTT. This photothermal-catalytic approach that combines simultaneous exogenous and endogenous activation is a potential option for tumor co-therapy.

An overview of the production methods for core-shell microspheres for parenteral controlled drug delivery

Core-shell microspheres hold great promise as a drug delivery system because they offer several benefits over monolithic microspheres in terms of release kinetics, for instance a reduced initial burst release, the possibility of delayed (pulsatile) release, and the possibility of dual-drug release. Also, the encapsulation efficiency can significantly be improved. Various methods have proven to be successful in producing these core-shell microspheres, both the conventional bulk emulsion solvent evaporation method and methods in which the microspheres are produced drop by drop. The latter have become increasingly popular because they provide improved control over the particle characteristics. This review assesses various production methods for core-shell microspheres and summarizes the characteristics of formulations prepared by the different methods, with a focus on their release kinetics.

Preparation of Magnetic-Luminescent Bifunctional Rapeseed Pod-Like Drug Delivery System for Sequential Release of Dual Drugs

Drug delivery systems (DDSs) limited to a single function or single-drug loading are struggling to meet the requirements of clinical medical applications. It is of great significance to fabricate DDSs with multiple functions such as magnetic targeting or fluorescent labeling, as well as with multiple-drug loading for enhancing drug efficacy and accelerating actions. In this study, inspired by the dual-chamber structure of rapeseed pods, biomimetic magnetic–luminescent bifunctional drug delivery carriers (DDCs) of 1.9 ± 0.3 μm diameter and 19.6 ± 4.4 μm length for dual drug release were fabricated via double-needle electrospraying. Morphological images showed that the rapeseed pod-like DDCs had a rod-like morphology and Janus dual-chamber structure. Magnetic nanoparticles and luminescent materials were elaborately designed to be dispersed in two different chambers to endow the DDCs with excellent magnetic and luminescent properties. Synchronously, the Janus structure of DDCs promoted the luminescent intensity by at least threefold compared to single-chamber DDCs. The results of the hemolysis experiment and cytotoxicity assay suggested the great blood and cell compatibilities of DDCs. Further inspired by the core–shell structure of rapeseeds containing oil wrapped in rapeseed pods, DDCs were fabricated to carry benzimidazole molecules and doxorubicin@chitosan nanoparticles in different chambers, realizing the sequential release of benzimidazole within 12 h and of doxorubicin from day 3 to day 18. These rapeseed pod-like DDSs with excellent magnetic and luminescent properties and sequential release of dual drugs have potential for biomedical applications such as targeted drug delivery, bioimaging, and sustained treatment of diseases.

pH-Sensitive silica-based core–shell nanogel prepared via RAFT polymerization: investigation of the core size effect on the release profile of doxorubicin

The novelty of this work is the synthesis of a core–shell nanogel that is based on silica nanoparticles as the core with different sizes via RAFT polymerization and its application to drug delivery.

Microfluidics for core-shell drug carrier particles - a review

Core-shell drug-carrier particles are known for their unique features. Due to the combination of superior properties not exhibited by the individual components, core-shell particles have gained a lot of interest. The structures could integrate core and shell characteristics and properties. These particles were designed for controlled drug release in the desired location. Therefore, the side effects would be minimized. So, these particles' advantages have led to the introduction of new methods and ideas for their fabrication. In the past few years, the generation of drug carrier core-shell particles in microfluidic chips has attracted much attention. This method makes it possible to produce particles at nanometer and micrometer levels of the same shape and size; it usually costs less than other methods. The other advantages of using microfluidic techniques compared to conventional bulk methods are integration capability, reproducibility, and higher efficiency. These advantages have created a positive outlook on this approach. This review gives an overview of the various fluidic concepts that are used to generate microparticles or nanoparticles. Also, an overview of traditional and more recent microfluidic devices and their design and structure for the generation of core-shell particles is given. The unique benefits of the microfluidic technique for core-shell drug carrier particle generation are demonstrated.

Equilibrium swelling of thermo-responsive copolymer microgels

Thermo-responsive (TR) hydrogels with a lower critical solution temperature swell strongly at temperatures below their volume phase transition temperature T_c and collapse above T_c. Biomedical application of these materials requires tuning the critical temperature in a rather wide interval. A facile method for modulation of T_c is to polymerize the basic monomers with hydrophilic or hydrophobic comonomers. Although the effectiveness of this method has been confirmed by experimental data, molar fractions of comonomers necessary for fine tuning of T_c in macroscopic gels and microgels are unknown. A simple model is developed for the equilibrium swelling of TR copolymer gels. Its adjustable parameters are found by fitting swelling diagrams on several macro- and microgels with N-isopropylacrylamide as a basic monomer. Good agreement is demonstrated between the experimental swelling curves and results of numerical analysis. An explicit expression is derived for the volume phase transition temperature as a function of molar fraction of comonomers. The ability of this relation to predict the critical temperature is confirmed by comparison with observations.

A model is developed for equilibrium swelling of thermo-responsive copolymer gels and is applied to predict the effect of molar fraction of comonomers on the volume phase transition temperature of macroscopic gels and microgels.

Core-shell nanoparticles used in drug delivery-microfluidics: a review

Developments in the fields of lab-on-a-chip and microfluidic technology have benefited nanomaterial production processes due to fluid miniaturization. The ability to acquire, manage, create, and modify structures on a nanoscale is of great interest in scientific and technological fields. Recently, more attention has been paid to the production of core-shell nanomaterials because of their use in various fields, such as drug delivery. Heterostructured nanomaterials have more reliable performance than the individual core or shell materials. Nanoparticle synthesis is a complex process; therefore, various techniques exist for the production of different types of nanoparticles. Among these techniques, microfluidic methods are unique and reliable routes, which can be used to produce nanoparticles for drug delivery applications.

Preparation and investigation of core-shell nanoparticles containing human interferon-α

Sustained release of active interferon-α (IFN-α) has been achieved from core-shell nanoparticles (NPs) prepared by aqueous precipitation of IFN-α-enriched human serum albumin (HSA-IFN-α) and layer-by-layer (L-b-L) by coating of the IFN-α NPs with poly(sodium-4-styrene) sulphonate (PSS) and chitosan (Chit). The concentration and the pH of HSA solution were optimized during the development of this method. Dynamic light scattering (DLS), zeta-potential, thermal analysis (differential scanning calorimetry (DSC) and termogravimetry (TG)), X-ray diffraction (XRD), IFN-α activity and morphology (transmission electron microscope (TEM)) studies were used to control the preparation and analyse the products. The dissolution kinetics of NPs was measured in vitro over 7 days in Hanson dissolution tester with Millex membrane. In vivo studies in Pannon white rabbit detected steady IFN-α plasma level for 10 days after subcutaneous injection administration of the HSA-IFN-α NPs. The IFN-α plasma concentration was detected by using the enzyme-linked immunosorbent assay (ELISA) method. In the present paper we discuss the preparation method, the optimization steps and the results of in vitro and in vivo release studies. It was established that 76.13% HSA-IFN-α are encapsulated in the core-shell NPs.

Mass, Size, and Density Measurements of Microparticles in a Quadrupole Ion Trap

The physical properties of microparticles, such as mass, size, and density, are critical for their functions. The comprehensive characterization of these physical parameters, however, remains a fundamental challenge. Here, we developed a particle mass spectrometry (PMS) methodology for determining the mass, size, and density of microparticles simultaneously. The collisional cross-section (CCS) and mass spectrometry (MS) measurements were performed in a single quadrupole ion trap (QIT), and the two modes can be switched easily by tuning the electric and gas hydrodynamic fields of the QIT. The feasibility of the method was demonstrated through a series of monodispersed polystyrene (PS) and silica (SiO₂) particle standards. The SiO₂/polypyrrole core-shell particles were also successfully characterized, and the measured results were verified by using conventional methods.

Sustained Delivery of Analgesic and Antimicrobial Agents to Knee Joint by Direct Injections of Electrosprayed Multipharmaceutical-Loaded Nano/Microparticles

In this study, we developed biodegradable lidocaine–/vancomycin–/ceftazidime–eluting poly(d,l–lactide–co–glycolide) (PLGA) nano/microparticulate carriers using an electrospraying process, and we evaluated the release behaviors of the carriers in knee joints. To prepare the particles, predetermined weight percentages of PLGA, vancomycin, ceftazidime, and lidocaine were dissolved in solvents. The PLGA/antibiotic/lidocaine solutions were then fed into a syringe for electrospraying. After electrospraying, the morphology of the sprayed nano/microparticles was elucidated by scanning electron microscopy (SEM). The in vitro antibiotic/analgesic release characteristics of the nano/microparticles were studied using high-performance liquid chromatography (HPLC). In addition, drug release to the synovial tissues and fluids was studied in vivo by injecting drug-loaded nano/microparticles into the knee joints of rabbits. The biodegradable electrosprayed nano/microparticles released high concentrations of vancomycin/ceftazidime (well above the minimum inhibition concentration) and lidocaine into the knee joints for more than 2 weeks and for over 3 days, respectively. Such results suggest that electrosprayed biodegradable nano/microcarriers could be used for the long-term local delivery of various pharmaceuticals.

Development Strategies and Prospects of Nano-based Smart Pesticide Formulation

Pesticides are important inputs for enhancing crop productivity and preventing major biological disasters. However, more than 90% of pesticides run off into the environment and reside in agricultural products in the process of application as a result of the disadvantages of conventional pesticide formulation, such as the use of a harmful solvent, poor dispersion, dust drift, etc. In recent years, using nanotechnology to create novel formulations has shown great potential in improving the efficacy and safety of pesticides. The development of nano-based pesticide formulation aims at precise release of necessary and sufficient amounts of their active ingredients in responding to environmental triggers and biological demands through controlled release mechanisms. This paper discusses several scientific issues and strategies regarding the development of nano-based pesticide formulations: (i) construction of water-based dispersion pesticide nanoformulation, (ii) mechanism on leaf-targeted deposition and dose transfer of pesticide nanodelivery system, (iii) mechanism on increased bioavailability of nano-based pesticide formulation, and (iv) impacts of nanoformulation on natural degradation and biosafety of pesticide residues.

Thermo-responsive molecularly imprinted polymer containing magnetic nanoparticles: Synthesis, characterization and adsorption properties for curcumin

A novel intelligent thermoresponsive-magnetic molecularly imprinted polymer (TMMIP) nanocomposite based on N-isopropylacrylamide (NIPAM) & Fe₃O₄ was designed for the controlled & sustained release of Curcumin (CUR) with the ability to response external stimulus. The TMMIP nanocomposite was prepared using acryl functionalized β-cyclodextrin (β-CD) and NIPAM as functional monomers and CUR as target molecule. The recognition cavities which caused by host-guest interactions had direct influence to enhanced drug loading and sustained release of CUR. According to in-vitro release experiment in two different temperatures (below & above LCST of NIPAM) the prolonged & controlled release of CUR were observed. The release rate could be controlled by changing the temperature because of the phase transition behavior of NIPAM monomer. Also, the proposed biosensor displayed effective role in separation science, reasonable adsorption capacity (77mgg^-1), fast recognition (10min equilibration), selective extraction toward CUR in the presence of structural analogues and easily separation using external magnetic field. Moreover, the synthesized TMMIP was confirmed by various characterization.

Facile encapsulation of hydroxycamptothecin nanocrystals into zein-based nanocomplexes for active targeting in drug delivery and cell imaging

Nano-drug delivery systems that integrate inorganic and organic or even bioactive components into a single nanoscale platform are playing a hugely important role in cancer treatment. In this article, the fabrication of a versatile nanocarrier based on self-assembled structures of gold nanoparticles (AuNPs)-zein is reported, which displays high drug-loading efficiency for needle-shaped hydroxycamptothecin (HCPT) nanocrystals. The surface modification with folate-conjugated polydopamine (PFA) renders them stable and also facilitates their selective cellular internalization and enhancement of endocytosis. The release of payloads from nanocomplexes (NCs) was shown to be limited at physiological pH (17.1±2.8%) but significantly elevated at endosomal/lysosomal pH (58.4±3.0%) and at enzymatic environment (81.4±4.2%). Compared to free HCPT and its non-targeting equivalent, HCPT@AuNPs-Zein-PFA exerted a superior tumor suppression capacity as well as low side effects due to its active and passive targeting delivery both in vitro and in vivo. These results suggest that the NCs with well-defined core@shell nanostructures encapsulated with HCPT nanocrystals hold great promise to improve cancer therapy with high efficiency in the clinic.

STATEMENT OF SIGNIFICANCE

A novel nanocomplex with HCPT nanocrystals encapsulated was designed to achieve selective cellular uptake by endocytosis, acid responsive release in the tumor microenvironment and excellent tumor suppression without toxicity. This nanocomplex with conjugation of folate was stable in the bloodstream, with minimal drug release in extracellular conditions, leading to prolonged blood circulation and high accumulation in tumor tissues. The entrapment of a nanocrystal drug into nanomaterials might be capable of delivering drugs in a predictable and controllable manner.

An innovative method for preparation of hydrophobic ion-pairing colistin entrapped poly(lactic acid) nanoparticles: Loading and release mechanism study

Hydrophobic ion-pairing (HIP) complexation has emerged as an efficient approach to enhance the entrapment of therapeutic peptides in the biodegradable polymer matrix. In the present study, we developed an innovative extraction method for preparation of HIP-colistin (CST, a polycationic peptide) using various water-insoluble anionic lipids. To determine the loading mechanism of HIP-CST entrapped poly(lactic acid) (PLA) nanoparticles (HIP-CST-PLA-NPs), the effects of anionic lipids and PLA molecular weight (Mw) on the unentrapped fraction (uf) of CST in PLA-NPs were investigated. And CST release mechanism from HIP-CST-PLA-NPs was also investigated by evaluating their release behavior and NP swelling. It is showed that HIP-CST retention in the PLA-NPs was imposed by their physical localization in the networks of the PLA chains, rather than the electrostatic attraction between anionic lipid and CST in serum. And HIP-CST-PLA-NPs in serum exhibited the swelling-controlled release behavior with a substantially accelerated release and NP swelling observed in comparison with that in phosphate buffer. Our results can effectively guide the preparation of biodegradable polymer based modified drug release systems with desired properties for peptides delivery.

Nanoencapsulation, Nano-guard for Pesticides: A New Window for Safe Application

The application of nanotechnology in pesticide delivery is relatively new and in the early stages of development. This technology aims to reduce the indiscriminate use of conventional pesticides and ensure their safe application. This critical review investigated the potential of nanotechnology, especially the nanoencapsulation process for pesticide delivery. In-depth investigation of various nanoencapsulation materials and techniques, efficacy of application, and current research trends are also presented. The focus of ongoing research was on the development of a nanoencapsulated pesticide formulation that has slow releasing properties with enhanced solubility, permeability, and stability. These properties are mainly achieved through either protecting the encapsulated active ingredients from premature degradation or increasing their pest control efficacy for a longer period. Nanoencapsulated pesticide formulation is able to reduce the dosage of pesticides and human exposure to them, which is environmentally friendly for crop protection. However, lack of knowledge of the mechanism of synthesis and lack of a cost-benefit analysis of nanoencapsulation materials hindered their application in pesticide delivery. Further investigation of these materials' behavior and their ultimate fate in the environment will help the establishment of a regulatory framework for their commercialization. The review provides fundamental and critical information for researchers and engineers in the field of nanotechnology and especially the use of nanoencapsulation techniques to deliver pesticides.

Micro- and nanoscale hierarchical structure of core–shell protein microgels

In this work, we fabricate core–shell protein microgels stabilized by protein fibrillation with hierarchical structuring on scales ranging from a few nanometers to tens of microns.

CdS nanorod–MFe2O4 (M = Zn, Co and Ni) nanocomposites: a heterojunction synthesis strategy to mitigate environmental deterioration

Fabrication of CdS nanorods encrusted with MFe₂O₄ nanoparticles (M = Zn, Co and Ni) gives magneto-luminescence nanocomposites with magnetically separable and visible light driven photocatalytic properties.

Facile synthesis of yolk–shell silica nanoparticles for targeted tumor therapy

Redox-responsive yolk–shell silica nanoparticles end-capped with rotaxane nanovalves were fabricated for targeted tumor therapy with high efficiency.