Core-shell Type Nanoparticles Research Articles

Toward coupling across inorganic/organic hybrid interfaces: polyaniline-coated gold nanoparticles with 4-aminothiophenol as gold-anchoring moieties

AbstractThe chemical binding between metal nanoparticles and (semi-)conductive polymer layers is essential to control the (opto-)electronic properties of such hybrid materials. Current approaches that achieve a conjugated binding of organic (semi-)conductive ligands to metal nanoparticles demonstrated promising functional properties, but are based on tedious multi-step organic synthesis to incorporate the required binding moieties at the chain ends of targeted macromolecular species. Herein, we explore the pre-functionalization of gold nanoparticles with p-aminothiophenol and subsequent surfactant-assisted formation of a poly(aniline) (PANI) shell as a means to access gold/PANI core–shell-type nanoparticles with enhanced conductive properties. Controlled surface deposition of these hybrid nanoparticles is achieved via template-assisted self-assembly. For these surface-deposited nanoparticles, charge transport properties are characterized at the nanoscale by conductive atomic force microscopy measurements and show a significant conductivity increase of our core–shell particles as compared to reference particles formed by conventional surfactant-assisted PANI-shell formation. Graphical Abstract

Modeling hyperthermia-based prostate cancer treatment in the presence of core-shell nanoparticles and large blood vessels under different ultrasound sonication patterns

The use of nanoparticles, as enhancing agents to transform ultrasound energy into heat for tumor destruction, is a promising approach to improve the efficacy of thermal-based cancer therapies. This study aimed to evaluate the effectiveness of core-shell type nanoparticles and the heat loss due to blood flow in large vessels under different patterns of ultrasound sonication in the hyperthermia-based treatment of the prostate cancer. For this purpose, the ultrasound attenuation coefficient in the prostate tumor embedded with nanoparticles was calculated using a scattering theory that was developed for core-shell type particles. Using the attenuation coefficient and the linear pressure wave equation, the acoustic power dissipated per unit volume of a three-dimensional (3D) model of the prostate tumor and its surrounding tissues was calculated. By simultaneous solving the bioheat, the convective energy, the continuity, the Navier-Stokes, and the thermal dose equations, the temperature and thermal dose distribution were computed in the model. The attenuation coefficient of the tumor showed a decreasing trend with increasing the thickness of the silica shell coating the magnetite or titania core. The capability of nanoparticles to enhance heat production in the medium was directly, and the blood flow heat loss was inversely, related to the degree of focus of the ultrasound beam. The thermal response of the tumor was influenced by its size and geometry, as well as the acoustic intensity. Titania nanoparticles were more efficient than the magnetite nanoparticles in ultrasound attenuation and heat production in the medium. Our findings can be useful in understanding the factors affecting the hyperthermia-based treatment of the prostate cancer using a combination of ultrasound and nanoparticles.

Fabrication of Nanostructures Consisting of Composite Nanoparticles by Open-Air PLD

We present a two-step physical method for the fabrication of composite nanoparticle-based nanostructures. The proposed method is based on the pulsed laser deposition (PLD) technique performed sequentially in vacuum and in air. As a first step, thin-alloyed films of iron with noble metal were deposited by PLD in vacuum. The films were prepared by ablation of a mosaic target formed by equal iron and gold sectors. As a second step, the as-prepared alloyed films were ablated in air at atmospheric pressure as the laser beam scanned their surface. Two sets of experiments were performed in the second step, namely, by applying nanosecond (ns) and picosecond (ps) laser pulses for ablation. The structure, microstructure, morphology, and optical properties of the samples obtained were studied with respect to the laser ablation regime applied. The implementation of the ablation process in open air resulted in the formation of nanoparticle and/or nanoparticle aggregates in the plasma plume regardless of the ablation regime applied. These nanoparticles and/or nanoaggregates deposited on the substrate formed a complex porous structure. It was found that ablating FeAu films in air by ns pulses resulted in the fabrication of alloyed nanoparticles, while ablation by ps laser pulses results in separation of the metals in the alloy and further oxidation of Fe. In the latter case, the as-deposited structures also contain core–shell type nanoparticles, with the shell consisting of Fe-oxide phase. The obtained structures, regardless of the ablation regime applied, demonstrate a red-shifted plasmon resonance with respect to the plasmon resonance of pure Au nanoparticles.

Nitrogen-doped carbon nanostructures embedded with Fe-Co-Cr alloy based nanoparticles as robust electrocatalysts for Zn-air batteries

Two types of nitrogen-doped carbon nanomaterials embedded with novel transition metal-based medium entropy alloy nanoparticles are synthesized via a simple, scalable, and cost-effective single-step pyrolysis route, by varying the stoichiometric ratio of iron and cobalt. The samples predominantly have bamboo-shaped nanotube morphology with some globular structures. The globules are core-shell type nanoparticles, i.e., containing the metallic-alloy nanoparticles encapsulated by the graphitic shell and embedded within defective amorphous-type carbon matrix. The electrochemical studies using these samples are conducted in basic medium to explore their potential for Zn-air batteries. Electrochemical measurements are carried out in 1 M and 0.1 M KOH, respectively, on a rotating disk electrode setup. The sample with higher cobalt content performs better for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) with regards to lower onset potential, lower Tafel slope and lower activation energy. However, the stability towards OER is better for the sample with higher iron content. The sample with higher cobalt content shows a better overall oxygen electrochemistry compared to the one with higher iron content, is at par with several state-of art electrocatalysts and is utilized for fabrication of a prototype Zn-air battery demonstrating its practical applicability.

A new core-shell-type nanoparticle loaded with paclitaxel/norcantharidin and modified with APRPG enhances anti-tumor effects in hepatocellular carcinoma.

Nanoparticle delivery systems have been shown to improve the therapeutic efficacy of anti-cancer drugs, including a variety of drugs for the treatment of hepatocellular carcinoma (HCC). However, the current systems show some limitations, and the delivery of more effective nanoparticle systems for anti-HCC drugs with better targeting ability are needed. Here, we created paclitaxel (PTX)/norcantharidin (NCTD)-loaded core–shell lipid nanoparticles modified with a tumor neovasculature-targeted peptide (Ala-Pro-Arg-Pro-Gly, APRPG) and investigated their anti-tumor effects in HCC. Core–shell-type lipid nanoparticles (PTX/NCTD-APRPG-NPs) were established by combining poly(lactic-co-glycolic acid) (PLGA)-wrapped PTX with phospholipid-wrapped NCTD, followed by modification with APRPG. For comparison, PTX-loaded PLGA nanoparticles (PTX-NPs) and PTX/NCTD-loaded core–shell-type nanoparticles without APRPG (PTX/NCTD-NPs) were prepared. The in vitro and in vivo anti-tumor effects were examined in HepG2 cells and tumor-bearing mice, respectively. Morphological and release characterization showed that PTX/NCTD-APRPG-NPs were prepared successfully and achieved up to 90% release of PTX in a sustained manner. Compared with PTX/NCTD-NPs, PTX/NCTD-APRPG-NPs significantly enhanced the uptake of PTX. Notably, the inhibition of proliferation and migration of hepatoma cells was significantly higher in the PTX/NCTD-APRPG-NP group than those in the PTX-NP and PTX/NCTD-NP groups, which reflected significantly greater anti-tumor properties as well. Furthermore, key molecules in cell proliferation and apoptosis signaling pathways were altered most in the PTX/NCTD-APRPG-NP group, compared with the PTX-NP and PTX/NCTD-NP groups. Collectively, PTX/NCTD-loaded core–shell lipid nanoparticles modified with APRPG enhance the effectiveness of anti-HCC drugs and may be an effective system for the delivery of anti-HCC drugs.

Evaluation of antioxidant, cytotoxicity, and anti-ovarian cancer properties of the Fe3O4@CS-Starch/Cu bio-nanocomposite

• Green supported of Cu NPs on Fe 3 O 4 nanoparticles using chitosan-starch composite. • The chitosan-starch composite acted as green reductant and stabilizing agent. • The Fe 3 O 4 @CS-Starch/Cu shown good anti-ovarian cancer activity. • The Fe 3 O 4 @CS-Starch/Cu shown good anti-oxidant activity. In the recent days, conjugated bio-nanomaterials involving magnetic core are interested as promising platform in new generation biological composites. In this regard, we report herein a novel Cu NPs supported chitosan-starch composite functionalized Fe 3 O 4 , a dual core–shell type nanoparticle (Fe 3 O 4 @CS-Starch/Cu). The post-synthetically modified biogenic material was analyzed in details over a number of physicochemical methods like, Transmission Electron Microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray Diffraction (XRD), energy-dispersive X-ray analysis (EDX), vibrating sample magnetometer (VSM) and inductively coupled plasma (ICP) techniques. In the medicinal part, the anticancer properties of Fe 3 O 4 @CS-Starch/Cu against ovarian cancer cell lines were determined. The free radical for the antioxidant effects was DPPH. The IC 50 were 198 and 155 µg/ml against Fe 3 O 4 @CS-Starch/Cu bio-nanocomposite and BHT. The IC 50 of the Fe 3 O 4 @CS-Starch/Cu bio-nanocomposite were 248, 189, and 281 µg/mL against ovarian cancer (PA-1, SW-626, and SK-OV-3) cell lines. In addition, the current study offer that Fe 3 O 4 @CS-Starch/Cu bio-nanocomposite could be a new potential adjuvant chemopreventive and chemotherapeutic agent against cytotoxic cells.

Proton conductivity dependence on the surface polymer thickness of core-shell type nanoparticles in a proton exchange membrane.

The proton exchange membrane (PEM) is the main component that determines the performance of polymer electrolyte fuel cells. The construction of proton-conduction channels capable of fast proton conduction is an important topic in PEM research. In this study, we have developed poly(vinylphosphonic acid)-block-polystyrene (PVPA-b-PS)-coated core-shell type silica nanoparticles prepared by in situ polymerization and a core-shell type nanoparticle-filled PEM. In this system, two-dimensional (2D) proton-conduction channels have been constructed between PVPA and the surface of silica nanoparticles, and three-dimensional proton-conduction channels were constructed by connecting these 2D channels by filling with the core-shell type nanoparticles. The proton conductivities and activation energies of pelletized PVPA-coated core-shell type nanoparticles increased depending on the coated PVPA thickness. Additionally, pelletized PVPA-b-PS-coated silica nanoparticles showed a good proton conductivity of 1.3 × 10-2 S cm-1 at 80 °C and 95% RH. Also, the membrane state achieved 1.8 × 10-4 S cm-1 in a similar temperature and humidity environment. Although these proton conductivities were lower than those of PVPA, they have advantages such as low activation energy for proton conduction, suppression of swelling due to water absorption, and the ability to handle samples in powder form. Moreover, by using PS simultaneously, we succeeded in improving the stability of proton conductivity against changes in the temperature and humidity environment. Therefore, we have demonstrated a highly durable, tough but still enough high proton conductive material by polymer coating onto the surface of nanoparticles and also succeeded in constructing proton-conduction channels through the easy integration of core-shell type nanoparticles.

Sonication - and γ-ray-mediated biomolecule-liquid metal nanoparticlization in cancer optotheranostics

Due to their unique characteristics, gallium-based liquid metal (LM) nanoparticles have been applied in various research fields. LM nanoparticle surface-modification design is essential for enhancing the original LM properties and physicochemical multifunctionalization. This study developed core-shell type nanoparticles based on eutectic gallium-indium and various biomolecules such as gelatin, deoxyribonucleic acid, lecithin, and bovine serum albumin using a sonicator and γ-ray radiator. In particular, the synthesized gelatin-functionalized LM nanoparticles exhibited excellent water dispersibility, unique morphology, uniform particle size, low toxicity, characteristic optical absorbance, potent photothermal conversion, high intracellular penetration, powerful photothermal anticancer efficacy, and functionalization with a fluorescent probe via dehydration condensation. The synthesized functional LM nanoparticles displayed in vivo fluorescent diagnosis of the targeted tumor location due to the enhanced permeability and retention effect. Moreover, the photothermal function of the LM nanoparticles was spatiotemporally activated by a biologically penetrable near-infrared laser to trigger targeted tumor ablation in mice. Thus, this study has provided an LM platform to design an effective, authentic nanoparticularization method and advance optotheranostics in cancer treatment.

Decorated silver nanoparticles on biodegradable magnetic chitosan/starch composite: Investigation of its cytotoxicity, antioxidant and anti-human breast cancer properties

Nanotechnology is the field to yield modern systems, tools, and materials by controlling at the atomic and molecular levels using the features that appear on those surfaces. Applications for nanotechnology in medical diagnostics, food, medicine, biotechnology, environment, energy, chemistry, physics, etc, introduce this technology as an interdisciplinary and cross-sectoral context. In the current years, conjugated bio-nanomaterials involving magnetic core are a promising platform in new generation biological composites. In this regard, we report herein a novel Ag NPs supported chitosan-starch composite functionalized Fe3O4, a dual core-shell type nanoparticle (Fe3O4@CS-Starch/Ag). In the oncological part of the recent study, the treated cells with Fe3O4@CS-Starch/Ag nanocomposite were assessed by MTT assay for 48 h about the cytotoxicity and anti-breast carcinoma properties on normal (HUVEC) and breast carcinoma cell lines i.e. Hs 578Bst, Hs 319. T, UACC-3133, UACC-732, and MDA-MB-453. The post-synthetically modified biogenic material was analyzed in detail over several physicochemical methods like, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), energy dispersive X-ray analysis (EDX) elemental mapping, transmission electron microscopy (TEM), vibrating-sample magnetometer (VSM), X-ray diffraction analysis (XRD), and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The viability of breast carcinoma cell lines reduced dose-dependently in Fe3O4@CS-Starch/Ag nanocomposite. The IC50 of Fe3O4@CS-Starch/Ag nanocomposite was 183, 207, 194, 279, and 252 µg/mL against Hs 578Bst, Hs 319. T, UACC-3133, UACC-732, and MDA-MB-453 cell lines, respectively.

Influence of heating rate on formation of nanostructured tungsten carbides during thermo-chemical processing

The structure, morphology and growth mechanism of nanostructured W-C phases during its synthesis by thermo-chemical processing at different heating rates was investigated. Higher heating rates of 8 and 4 K/min led to the formation of core–shell type nanoparticles via sequential formation of the trigonal ε-W2C (Space group:P3¯m1) followed by the hexagonal α-WC layer (Space group: P6¯m2). It appears that the formation of the core–shell possibly initiates by the nucleation of metastable W2C to form octahedral core, which subsequently act as the nucleation site for the growth of the lower order α-WC from the surface layer. The surface layer encapsulating the metastable phase possibly restricts the coarsening of the particles to a size less than 100 nm. Slow heating rate of 1 K/min, on the other hand, leads to the formation of single phase ε-W2C with abnormal particle size growth and epitaxial morphology along (001) crystallographic plane. This observation confirms that the anisotropic lattice volume expansion in the crystalline ε-W2C induced diffusion of carbon leading to abnormal particle coarsening.

Aggregation-induced emission-active hyperbranched polymer-based nanoparticles and their biological imaging applications

Herein, we developed a facile one-pot approach to prepare amphiphilic aggregation-induced emission (AIE)-active hyperbranched fluorescent nanoparticles with a core–shell structure. This was conducted via the addition reaction between tetraphenylethylene (TPE)-OH, isophorone diisocyanate, and hyperbranched polyglycidol (HPG) using a one-pot method. The resultant AIE-active hyperbranched polymer structure was characterized by 1H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The amphiphilic AIE-active polymer was prone to self-assemble in an aqueous solution to form core–shell type nanoparticles with a TPE core and hydroxyl groups on the core surface. The self-assembly of nanoparticles in the aqueous solution was characterized using dynamic light scattering, ultraviolet–visible spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. Aggregation behavior of TPE-HPG polymer in water and diethyl ether was studied by dissipative particle dynamics simulation. Furthermore, these TPE-HPG nanoparticles exhibited a strong blue luminescence in the aqueous solution due to the aggregation of the AIE feature of TPE. These polymeric nanoparticles showed high water solubility, good photostability, and biological imaging properties. The cell viability assay and confocal microscopy imaging results suggested that the TPE-HPG fluorescent polymeric organic nanoparticles (FPNs) have low cytotoxicity and excellent biocompatibility. Thus, TPE-HPG FPNs are excellent candidates for biomedical applications.

New Design Strategies for Controlling the Rate of Hydrophobic Drug Release from Nanoemulsions in Blood Circulation.

The intravenous administration of drug-loaded nanoparticles (NPs) is needed to achieve passive or active targeting in disease tissues. However, when the loaded drug is a hydrophobic small molecule, the NPs fail to reach adequate plasma drug concentrations mainly because of premature drug release. The pharmacokinetics of such drugs can be controlled by covalent modification, but this approach could compromise the safety or potency of the drug. In this study, we investigated two formulation parameters that could be used to improve the plasma concentrations of unmodified drugs that are loaded in a nanoemulsion (NE), a core-shell type NP. The first parameter is the loading ratio, and the second is the affinity of the drug to the core. Optimized NEs with reduced drug loading and with a high drug-core affinity resulted in a 12.4- and 11.2-fold increase in the plasma retention of curcumin and paclitaxel, respectively. Our strategy for enhancing the drug-core interaction affinity relied on mixing oils and surfactants to achieve cooperativity in noncovalent interactions, such as hydrophobic interactions, hydrogen bonding, and π-π stacking, which was further confirmed by theoretical calculations of interaction affinities. Finally, we report on the development of a cinnamic acid-derived oil-like material as a novel drug vehicle with exceptional solubilizing ability that could be used in intravenous formulations of NEs.

Biocompatible superparamagnetic core-shell nanoparticles for potential use in hyperthermia-enabled drug release and as an enhanced contrast agent

Superparamagnetic iron oxide nanoparticles (SPIONs) and core-shell type nanoparticles, consisting of SPIONs coated with mesoporous silica and/or lipid, were synthesised and tested for their potential theranostic applications in drug delivery, magnetic hyperthermia and as a contrast agent. Transmission Electron Microscopy (TEM) confirmed the size of bare and coated SPIONs was in the range of 5–20 nm and 100–200 nm respectively. The superparamagnetic nature of all the prepared nanomaterials as indicated by Vibrating Sample Magnetometry (VSM) and their heating properties under an AC field confirm their potential for hyperthermia applications. Scanning Column Magnetometry (SCM) data showed that extrusion of bare-SPION (b-SPION) dispersions through a 100 nm polycarbonate membrane significantly improved the dispersion stability of the sample. No sedimentation was apparent after 18 h compared to a pre-extrusion estimate of 43% settled at the bottom of the tube over the same time. Lipid coating also enhanced dispersion stability. Transversal relaxation time (T2) measurements for the nanoparticles, using a bench-top relaxometer, displayed a significantly lower value of 46 ms, with a narrow relaxation time distribution, for lipid silica coated SPIONs (Lip-SiSPIONs) as compared to that of 1316 ms for the b-SPIONs. Entrapment efficiency of the anticancer drug, Doxorubicin (DOX) for Lip-SPIONs was observed to be 35% which increased to 58% for Lip-SiSPIONs. Moreover, initial in-vitro cytotoxicity studies against human breast adenocarcinoma, MCF-7 cells showed that % cell viability increased from 57% for bSPIONs to 82% for Lip-SPIONs and to 87% for Lip-SiSPIONs. This suggests that silica and lipid coatings improve the biocompatibility of bSPIONs significantly and enhance the suitability of these particles as drug carriers. Hence, the magnetic nanomaterials prepared in this work have potential theranostic properties as a drug carrier for hyperthermia cancer therapy and also offer enhancement of contrast agent efficacy and a route to a significant increase in dispersion stability.

Novel neuroprotection using antioxidant nanoparticles in a mouse model of head trauma.

Free radicals and reactive oxygen species are related to deteriorating pathological conditions after head trauma because of their secondary effects. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) scavenges free radicals; however, this molecule is also toxic. Here, we have evaluated the neuroprotective effect of antioxidant nanoparticles, which consisted of a novel core-shell type nanoparticle containing 4-amino-TEMPO, that is, redox-active nitroxide radical-containing nanoparticles (RNPs). Institute of Cancer Research mice were subjected to a head-impact procedure, randomly divided into four groups and intravenously (3 mg/kg) administered phosphate-buffered saline, TEMPO, micelle (a self-assembling block copolymer micelle without a TEMPO moiety), or RNP through the tail vein immediately thereafter and intraperitoneally at days 1, 3, and 5 after traumatic brain injury (TBI). The RNP distribution was detected by rhodamine labeling. Cognitive behavior was assessed using the neurological severity score and a rotarod test at days 1, 3, and 7 following TBI, and contusion volume was measured at day 7 after TBI. Free radical-scavenging capacity was analyzed by electron paramagnetic resonance on day 1 after TBI, and immunostaining was used to observe mobilization of microglia (Iba-1) and rescued neuronal cells (NeuN). Redox-active nitroxide radical-containing nanoparticle was detected in the microvessels around the injured area in the brain. Cognitive behavior assessment was significantly better, and contusion volume was significantly smaller in the RNP group compared with the other groups. Superoxide anion scavenging capacity was significantly higher in the RNP group, and neuronal loss was significantly suppressed around the injured area at day 7 after TBI. Furthermore, in the RNP group, neurodegenerative microglia production was suppressed at days 3 and 7 after TBI, whereas neuroprotective microglia production was higher at day 7 after TBI. The RNP administration after TBI improved cognitive behavior and reduced contusion volume by improving reactive oxygen species scavenging capacity. Therefore, RNP may have a neuroprotective effect after TBI. Therapeutic test.

Facile-controlling of the coating amount of poly(acrylic acid)-b-polystyrene coated on silica nanoparticles for polymer electrolyte membrane

We have successfully demonstrated a polymer electrolyte membrane (PEM) composed of core–shell type nanoparticles (NPs) which are silica NPs coated with poly(acrylic acid)-b-polystyrene (PAA-b-PS). In this work, for further improvement of proton conductive performance, we focus on the relationship between the coating amount of PAA and proton conduction performance. The PAA coating amount can be facilely controlled by changing the polymerization conditions. With the optimized PAA coating amount, the proton conductivity shows 9.2 × 10−4 S cm−1 at 60 °C and 98% relative humidity with low activation energy (Ea = 0.33 eV). In addition, with coating PS on silica@PAA, silica@PAA-b-PS shows the proton conduction performance in a wide humidity range. It suggests that coated PS prevents the PAA swelling and suppresses flowing moisture out from the membrane. This report indicates that core–shell type NPs show great potential for a good PEM membrane in various operation conditions by simple polymerization conditions.

On the first evidence of exchange-bias feature in magnetically contrasted consolidates made from CoFe2O4-CoO core-shell nanoparticles

Hetero-nanostructures based on magnetic contrast oxides have been prepared as highly dense nanoconsolidates. Cobalt ferrite-cobalt oxide core-shell type nanoparticles (NPs) were synthesized by seed mediated growth in polyol and subsequently consolidated by Spark Plasma Sintering (SPS) at 500 °C for a few minutes while applying a uniaxial pressure of 100 MPa. It is interesting to note that the exchange bias feature observed in the core-shell NPs is reproduced in their ceramic counterparts, or even attenuated. A systematic structural characterization was then carried out to elucidate the decrease in the exchange magnetic field, involving mainly advanced X-ray diffraction, zero-field and in-field 57Fe Mössbauer spectrometry, magnetic measurements and electron microscopy.

Stokes shift engineered, stable core-shell perovskite nanoparticle – Poly(methyl methacrylate) composites with high photoluminescence quantum yield

Organometallic lead halide perovskites are well known for its excellent and unique light-harvesting properties. This brands them as a promising candidate in almost all the optoelectronic devices. Present work demonstrates the synthesis of methylammonium lead bromide, MAPbBr3 quantum dots (QDs) of diameter less than 4 nm and methylammonium - octylammonium lead bromide core-shell type nanoparticles (CSNPs) with a core diameter of about 1–2 nm surrounded by a shell of thickness 4 nm. The core-shell structure was confirmed from crystal structure analysis – X-ray diffraction pattern, transmission electron microscopy (TEM) images and an increased stokes shift between absorption edge and the photoluminescence emission peak. These core-shell nanoparticles with high photoluminescence quantum yield (PLQY) and color tuning ability were incorporated into poly (methyl methacrylate) (PMMA) matrix to form transparent nanocomposites which were highly stable, with reduced wettability and a high PLQY of 88%. PLQY stability of composites towards humidity was examined by keeping the samples fully immersed in water for 18 h, after which PMMA composites were showing PLQY ∼83%, no considerable difference was found compared to dry composites. Dry films (kept sealed in covers) were found to be relatively stable for about one year retaining PLQY of 13%. The composite films of core-shell particles were used to demonstrate a prototype of down converting light emitting diode (LED), emitting pure green light capable of improving the quality of display devices.

The effect of synthesis conditions and tunable hydrophilicity on the drug encapsulation capability of PLA and PLGA nanoparticles.

Three drugs with different hydrophilicity are encapsulated in poly-lactide (PLA) and Poly(lactide-co-glycolide) (PLGA) drug delivery systems prepared by ring-opening polymerization (ROP). Formation of well-defined core-shell type nanoparticles (NPs) is observed for α-tocopherol (TP) and by systematically altering the hydrophilicity of the drug carrier NPs the entrapment efficiency (EE (%)) can be remarkably controlled. The highest (90%) of EE (%) is obtained for the most lipophilic TP from the applied three drugs in the 75% lactide-containing PLGA75 NPs, which is ca. 69% for PLA NPs. Subsequent to drug loading the detailed characterization of the polymers and the formed NPs was carried out. Precipitation titrations reveal that our PLGAs have narrower weight distribution than the commercially available polymer enabling favorable properties to obtain NPs with better size distribution. It is pointed out that during the synthesis the applied solvent and stabilizing agent play a decisive role in the size distribution and stability of the drug carrier NPs. The Pluronic F127-stabilized NPs have the smallest diameter (ca. 190 nm) with less polydispersity among the applied stabilizing agent in nanoprecipitation.

Counterion coupled (COCO) gemini surfactant capped Ag/Au alloy and Ag@Au core-shell nanoparticles for cancer therapy.

Hybrid silver (Ag)–gold (Au) nanoparticles (NPs) with different sizes and compositions were synthesized. Ag/Au alloy and Ag@Au core–shell type NPs were prepared from Ag and Au with various ratios using the COCO gemini surfactant, 1,6-bis (N,N-hexadecyldimethylammonium) adipate (COCOGS), 16-6-16 as a stabilizer. The formation of the Ag/Au alloy and Ag@Au core–shell was confirmed by UV-visible absorption spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX) and selected area electron diffraction (SAED) patterns. Depending on the composition of the Ag/Au alloy NPs, the λmax values varied from 408 nm to 525 nm. FTIR measurements were used to evaluate the adsorption of the COCO gemini surfactant (16-6-16) on the Ag/Au alloy and Ag@Au core–shell surface. In this present work, we study how to achieve the stability and activity of the COCO gemini surfactant (16-6-16) capped Ag/Au alloy and Ag@Au core–shell NPs for developing novel anti-cancer agents by evaluating their potentials in the Hep-2 cell line model. Thus the developed core–shell NPs were possibly involved in inducing cytotoxicity followed by inhibition of cell proliferation to the cancer cells with apoptosis induction. The developed core–shell NPs might serve as highly applicable agents in the development of next-generation cancer chemotherapeutic agents.

Decreasing the shell ratio of core-shell type nanoparticles with a ceria core and polymer shell by acid treatment

Core-shell type nanoparticles with a ceria core and polymer shell have good dispersibility. Some applications, such as fillers for increasing the refractive index and/or protecting resin films from ultraviolet (UV) light, i.e., UV cutting, require a smaller shell. Previous studies have decreased the shell weight by heat treatment in gas; however, the dispersibility of the treated nanoparticles was poor in water or alcohol. In this study, we investigated the efficacy of acid treatment for decreasing the shell weight and also evaluated the dispersibility of acid-treated nanoparticles. The thus-formed nanoparticles treated by acetic acid and formic acid show not only good dispersibility but also a well decreased shell thickness. The structure of the shell after acetic acid treatment was found to be the same as that of the untreated core-shell nanoparticles; moreover, acetic acid was present in the shell. Furthermore, by using the acetic-acid-treated nanoparticles, a transparent resin film without nanoparticle aggregation could be obtained.