Alginate–chitosan micro- and nanoparticles for transmucosal delivery of proteins

The properties of protein-containing micro- and nanoparticles that were produced from alginate and chitosan using the methods of layer-by-layer polyelectrolyte adsorption and ionotropic gelation have been compared. The encapsulation efficiency of proteins (aprotinin, interferon, and human insulin), the size and ζ-potential of the particles, the mucin binding, and the protein release under physiological conditions have been studied. The prospects for the possible mucosal application of the particles are discussed.     

Preparation of pH- and thermo-sensitive chitosan-PNIPAAm core–shell nanoparticles and evaluation as drug carriers

Environmentally sensitive polysaccharide nanoparticles (NPs) were prepared by in situ polymerization of N-isopropylacrylamide (NIPAAm) monomer in the presence of chitosan (CS) micelles. First, CS was found to develop a cationic micelle-like structure in the acetic acid solution when its concentration was increased to above the critical micelle concentration, as evidenced by fluorescence and TEM. When the NIPAAm was polymerized in the CS micelle solution by using potassium persulfate as initiator, the produced PNIPAAm with anionic chain end(s) became hydrophobic, as long as the reaction temperature was above its phase transition temperature; and therefore it would diffuse into the hydrophobic core of the CS micelles, producing CS-PNIPAAm core–shell NPs. Increasing the feeding amount of NIPAAm increased the monomer conversion and therefore the particle size; yet it decreased the surface zeta potential. Moreover, the CS-PNIPAAm NPs were sensitive to both pH value and temperature. For the study of drug release properties, doxycycline hyclate was used as a model drug and loaded into the NPs at pH 4.5 and 25 °C. The result illustrated that these NPs had a continuous drug release behavior up to 1 week, depending on the pH value and temperature. In addition, enzyme or hydrogen peroxide capable of degrading CS shell was added in the solution to facilitate the drug release.     

Characterization and preparation of core–shell type nanoparticle for encapsulation of anticancer drug

The aim of this study is to prepare delivery vehicles of paclitaxel using low molecular weight water-soluble chitosan (LMWSC) and evaluate them as an anticancer drug delivery system. LMWSC was modified with methoxy polyethylene glycol (LMWSC-MPEG, ChitoPEG), and then it was conjugated with cholesterol (LMWSC-MPEG-Chol). Core–shell type LMWSC-MPEG-Chol nanoparticles (LMWSC-NPs) were prepared by the dialysis method, and the core–shell structure was confirmed by ¹H NMR analysis. To this polymer, paclitaxel was encapsulated and core–shell type nanoparticles were prepared. The release tests indicated that release of paclitaxel from the core–shell type nanoparticles and its transport across the dialysis membrane was slower than dialysis of free paclitaxel. In a cytotoxicity study using CT26 cell, the paclitaxel-encapsulated core–shell type nanoparticles (LMWSC-NPs) showed a toxicity against tumor cells similar to paclitaxel itself. The results of a tumor inhibition test with CT26 implanted upon mouse tumor models in vivo indicated that the application of a dose of 10 mg/kg of LMWSC-NPT showed a superior survival rate, and a slower tumor growth than when paclitaxel alone was administered, although the tumor growth and survival rate were not significantly changed at a dose of 2 mg/kg. The LMWSC-NPT dose above 10 mg/kg showed a superior antitumor activity.     

Functional mesoporous silica nanoparticles for photothermal-controlled drug delivery in vivo

Release me! A new class of photothermal-responsive [2]rotaxane-appended mesoporous silica nanoparticles (MSNPs) was developed. Remote-controlled movement of the α-cyclodextrin ring?(green) upon trans-cis isomerization of the azobenzene axle?(red) enables the loading and release of drugs on demand. Curcumin-loaded MSNPs were shown to release curcumin into zebrafish larvae upon treatment with visible light or heat.     

Core–shell hybrid material for ZnO nanorods generation

The aim of our study consisted in obtaining ZnO nanorods using a photonic crystal (PC) structure as substrate. For obtaining of such structures, a PC presenting with electroconductive properties was chosen. Thus, the first step was represented by the synthesis of a copper nanoparticles shell composed by a maximum of seven layers of inorganic particle. This core–shell structure was subsequently used for the generation of ZnO nanorods by electrochemical deposition. The obtained materials were characterized by SEM, dynamic light scattering, UV–Vis, and X-ray powder diffraction analysis.     

Novel pentablock copolymer (PLA–PCL–PEG–PCL–PLA)-based nanoparticles for controlled drug delivery: effect of copolymer compositions on the crystallinity of copolymers and in vitro drug release profile from nanoparticles

The purpose of this investigation was to design novel pentablock copolymers (polylactide–polycaprolactone–polyethylene glycol–polycaprolactone–polylactide) (PLA–PCL–PEG–PCL–PLA) to prepare nanoparticle formulations which provide continuous delivery of steroids over a longer duration with minimal burst effect. Another purpose was to evaluate the effect of poly(l-lactide) (PLLA) and poly(d,l-lactide) (PDLLA) incorporation on crystallinity of pentablock copolymers and in vitro release profile of triamcinolone acetonide (selected as model drug) from nanoparticles. PLA–PCL–PEG–PCL–PLA copolymers with different block ratio of PCL/PLA segment were synthesized. Release of triamcinolone acetonide from nanoparticles was significantly affected by crystallinity of the copolymers. Burst release of triamcinolone acetonide from nanoparticles was significantly minimized with incorporation of proper ratio of PDLLA in the existing triblock (PCL–PEG–PCL) copolymer. Moreover, pentablock copolymer-based nanoparticles exhibited continuous release of triamcinolone acetonide. Pentablock copolymer-based nanoparticles can be utilized to achieve continuous near–zero-order delivery of corticosteroids from nanoparticles without any burst effect.     

Iron cross-linked carboxymethyl cellulose—gelatin complex coacervate beads for sustained drug delivery

The formation and smooth recovery of ibuprofen encapsulated in microcapsules using gelatin and carboxymethyl cellulose (CMC) complex coacervation without glutaraldehyde were the objectives of this investigation. The microcapsules were recovered as ionically cross-linked beads using aqueous ferric chloride in 50 vol.% of 2-propanol. A physical mixture of CMC/gelatin (FP1) and CMC alone (FP2) beads was also prepared for comparison. The drug-entrapment efficiency of complex coacervate beads (FP3-FP5) was dependent on the drug-to-polymer ratio and was in the range of 86–92 mass %. Beads prepared with the highest ratio of the drug (FP5) exhibited the lowest entrapment. FP1 and FP2 beads exhibited an entrapment efficiency of 98.5 mass % and 91.3 mass %, respectively. Infrared spectroscopy (FTIR) revealed different functional groups in complex coacervate, physical mixture and FP2 beads. Optical and scanning electron microscopy revealed the distinct appearance and surface morphology of the various beads. The stable and crystalline nature of ibuprofen in the beads was confirmed by FTIR and differential scanning calorimetry (DSC), respectively. Ibuprofen release from FP1 and FP2 beads was very slow and unsuitable for oral delivery. The bead prepared by complex coacervation (FP5) showed a better release profile over 48 h and could be developed as a sustained drug delivery system.     

Sol–gel behavior of a novel nanodroplet biomaterial for drug delivery

Nanodroplets can be considered as those nano/microemulsions in which the oil itself forms the active agent and the droplet size ambits in the nanometer range. Eugenol is an anti-inflammatory agent and its nanodroplet gel (NDG) has immense potential for topical use. Topical gels oblige some rheological characteristics to nail down the demands of proper application, stability and storage. Thus, the purpose of our study was to comprehend the effect of eugenol on the sol–gel tranisition properties of its NDGs. Towards this goal nanodroplets of eugenol were prepared and evaluated and the three selected nanodroplet formulations with 5, 10 and 5% v/v eugenol were converted into topical gel formulation using 1% w/w Carbopol 940. The NDGs were characterized using frequency sweep, creep recovery and thixotropy. All these tests pointed out that eugenol concentration has significant effect on the sol–gel behavior of NDGs. The NDGs exhibited more viscous (sol) properties than elastic (gel) properties as observed from the frequency sweep studies. The thixotropy of the NDGs was found to decrease with increase in eugenol concentration. Efforts have been made to explain the study results using mechanistic approach. The outcomes of our research studies could be of great use in future endeavors towards development of a topical NDG of eugenol with tailored sol–gel behavior.     

Formulation of pH-sensitive aminated chitosan–gelatin crosslinked hydrogel for oral drug delivery

The objective of this study is to develop efficient pH-sensitive hydrogel based on aminated chitosan (AmCs) and gelatin (Gel) biopolymers for oral drug delivery. Herein, AmCs was chemically crosslinked with gelatin (Gel) biopolymer with different ratios, while their structures, thermal profiles and morphological properties were investigated by FTIR, TGA and SEM characterization tools, respectively. Moreover, gel-content, crosslinking density and rheological analysis were also performed. The results clarified that the developed AmCs-Gel crosslinked hydrogel displayed variable pH-sensitive swelling profiles. By increasing AmCs ratio, the swelling ratio was boosted at pH 1.2 and declined at pH 7.4. Besides, by increasing gelatin ratio in the hydrogel matrix, the loading efficiency of Oseltamivir phosphate (as a model of drug) was augmented and reached maximum value of 79.0% by AmCs-Gel (2:3) crosslinked hydrogel. The in vitro drug release profiles were investigated for 6 h in simulated gastric fluid [SGF; pH 1.2] and simulated colon fluid [SCF; pH 7.4]. Variable release profiles were realized depending on variation of AmCs and Gel ratios in the crosslinked hydrogel matrix. Finally, the formulated smart crosslinked AmCs-Gel hydrogels demonstrated acceptable biodegradability with no cellular toxicity, suggesting their applicability as pH-sensitive oral drug carriers.     

Core–shell thermal-responsive and magnetic molecularly imprinted polymers based on mag-yeast for selective adsorption and controlled release of tetracycline

A novel thermal-responsive and magnetic molecularly imprinted polymers (TMMIPs) were prepared based on mag-yeast via a mild and effective method; the obtained TMMIPs were used for selective adsorption and release of tetracycline from aqueous solution. Imprinted polymerization directly occured on the surface of microspheres, and core–shell imprinted polymers were developed via in situ precipitation polymerization. The properties of obtained TMMIPs were characterized by scanning electron and transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, thermo-gravimetric analysis and so on. The adsorption equilibrium data were well described by Langmuir isotherm model. Kinetic experiments showed the adsorption process reached the equilibrium within 60 min, and the pseudo-second-order kinetic model was used to fit the adsorption data well. TMMIPs exhibited magnetic sensitivity, magnetic stability and thermal stability. Reversible recognition and release of template molecule were realized by changing environmental temperatures. Several other antibiotics were selected as model analytes to evaluate the selective recognition performance of TMMIPs. The TMMIPs have good temperature response, selectivity and reusability, making them possible in applying for antibiotics adsorption and controlled release.     

Investigation of controlled release properties and anticancer effect of folic acid conjugated magnetic core–shell nanoparticles as a dual responsive drug delivery system on A-549 and A-431 cancer cell lines

Research on Chemical Intermediates - Epirubicin loaded on magnetite-coated calcium ferrite conjugated folic acid (Fe3O4@CaFe2O4-FA@EPI) was synthesized and characterized using various techniques...     

Synthesis and characterization of chitosan–polyvinylpyrrolidone–bovine serum albumin-coated magnetic iron oxide nanoparticles as potential carrier for delivery of tamoxifen

The proposed study examined the preparation of chitosan (CS)–polyvinylpyrrolidone (PVP)–bovine serum albumin (BSA)-coated magnetic iron oxide (Fe₃O₄) nanoparticles (Fe₃O₄–CS–PVP–BSA) to use as potential drug delivery carriers for delivery of tamoxifen drug (TAM) . The anticancer drug selected in this study was tamoxifen which can be used for the human breast cancer treatment. These prepared nanoparticles were characterized by FTIR, XRD, SEM, AFM, TEM, CD and VSM techniques. The swelling studies have been measured at different (10, 20, 30, 40, 50%) drug loading. The mean particle size of the tamoxifen-loaded nanoparticles system (Fe₃O₄–CS–TAM, Fe₃O₄–CS–TAM–PVP and Fe₃O₄–CS–TAM–PVP–BSA) as measured by Malvern Zetasizer ranged between 350 ± 2.3 and 601 ± 1.7 nm. As well as these drug-loaded nanoparticles were positively charged. The zeta potential was in the range of 28.9 ± 3.5 and 50.8 ± 3.9 mV. The encapsulation efficiency was between 63.60 ± 2.11 and 96.45 ± 2.12%. Furthermore, in vitro release and drug loading efficiency from the nanoparticles were investigated. The cytotoxicity of prepared nanoparticles was verified by MTT assay. In vitro release studies were executed in 4.0 and 7.4 pH media to simulate the intestinal and gastric conditions and different temperature (37 and 42 °C). Hence, the prepared tamoxifen-loaded nanoparticles system (Fe₃O₄–CS–TAM, Fe₃O₄–CS–TAM–PVP and Fe₃O₄–CS–TAM–PVP–BSA) could be a promising candidate in cancer therapy.     

α-Fe2O3@carbon core–shell nanostructure for luminescent upconversion and photocatalytic degradation of methyl orange

Research on Chemical Intermediates - The unique characteristics of metal–organic frameworks such as structural tunability, high surface area, low density, and tailored porosity have made this...     

Core–shell structured phosphorescent nanoparticles for detection of exogenous and endogenous hypochlorite in live cells via ratiometric imaging and photoluminescence lifetime imaging microscopy

We report a ratiometric phosphorescence sensory system for hypochlorite (ClO^–) based on core–shell structured silica nanoparticles. Two phosphorescent iridium(iii) complexes were immobilised in the inner solid core and outer mesoporous layer of the nanoparticles, respectively. The former is insensitive to ClO^– and thus serves as an internal standard to increase the accuracy and precision, while the latter exhibits a specific and significant luminogenic response to ClO^–, providing high selectivity and sensitivity. Upon exposure to ClO^–, the nanoparticles display a sharp luminescence colour change from blue to red. Additionally, intracellular detection of exogenous and endogenous ClO^– has been demonstrated via ratiometric imaging and photoluminescence lifetime imaging microscopy. Compared to intensity-based sensing, ratiometric and lifetime-based measurements are independent of the probe concentration and are thus less affected by external influences, especially in intracellular applications.     

Electrochemical determination of the surface composition of Pd–Pt core–shell nanoparticles

Different amounts of Pt atoms were deposited onto the surface of Pd nanoparticles supported on carbon black by hydroquinone reduction method in anhydrous ethanol. Here, we surveyed electrochemical probing of surface compositions of Pd–Pt surface alloys. They were calculated from hydrogen desorption, carbon monoxide adlayer oxidation, and reduced carbon dioxide oxidation charges. The surface composition of Pt drastically increased up to Pt[0.3]/Pd/C (23.1 at.% of Pt) and then approached that of pure Pt with the moderate rate of increase.     

Photo and redox dual-stimuli-responsive β-cyclodextrin-ferrocene supramolecules for drug delivery

Abstract

Amphiphilic photo and redox dual-stimuli-cleavable β-cyclodextrin-ferrocene supramolecules were synthesized through noncovalent interactions of ferrocene (Fc) and β-cyclodextrin (β-CD) born by 5-hydroxy-2-nitrobenzyl alcohol (ONB), a photodegradable linker between the β-CD and poly(4-substituted-?-caprolactone) (PXCL _n ) chain. The terminal host–guest MPEG-Fc/β-CD-ONB-PXCL _n complex can formed micelles in the aqueous phase. The critical micelle concentration ranged from 3.16 to 11.50?mg L^?1. The drug-loading content and drug entrapment efficiency of the complex were lower than those of the parent β-CD. When exposed to ultraviolet irradiation and hydrogen peroxide, complex micelles could dissociate and efficiently release the loaded drug. Nanoparticles exhibited almost no toxicity at concentrations up to 1000?μg mL^?1. The uptake of doxorubicin-incorporated micelles by HeLa cells was faster than that of free doxorubicin within the first 5?min. DOX-loaded MPEG₄₅-Fc/β-CD-ONB-PMCL₂₃ micelles effectively inhibited the proliferation of HeLa cells with a half maximal inhibitory concentration (IC₅₀) of 3.8?µg mL^?1.     

Core–shell micron-scale composites of titanium oxide and carbide formed through controlled thermal-plasma oxidation

Core–shell structured micron-scale spheres of titanium oxide and carbide were prepared by the controlled in-flight oxidation of a powder of irregularly shaped titanium-carbide particles in an argon–oxygen thermal plasma. Mono-dispersed core–shell particles with rutile shells and TiC cores were formed by an intermediate-rate input of oxygen to the plasma gas. The partial oxidation of the TiC particles in the liquid phase was accompanied by spheroidization of the surface oxide melt, thus giving rise to a core–shell composite under rapid quenching. TiO₂–TiC core–shell composites have potential as new materials for roles such as light-scattering media, photo-catalysts, and electro-rheorogical fluids.     

Recent progresses of exosome–liposome fusions in drug delivery

Exosomes are membrane-bound nanoscale extracellular vesicles, which produced by almost all organisms.Due to the excellent biocompatibility, long circulation time as well as low immunogenicity, exosomes as naturally-derived drug delivery carriers have experienced explosive growth over the past decades. However, issues such as insufficient loading efficiency, heterogeneous delivery efficiency, uncontrollable targeting ability, and low production limit their wide application. Recently, the emerging...