Flow field-flow fractionation and single particle inductively coupled plasma mass spectrometry as a powerful tool for tracking and understanding the sensing mechanism of Ag-Au bimetallic nanoparticles toward cobalt ions.

BACKGROUND: Ag-Au bimetallic nanoparticles (BNPs), synthesized by using citrate reduction of Ag and Au ions, were used as sensor for detection of Co2+. In order to optimize sensing performance, it is necessary to control the particle size and size distribution of the original Ag-Au BNPs. Therefore, analytical methods based on the use of single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) and flow-field flow fractionation (FlFFF)-ICP-MS were developed to track the signal of Ag and Au in bimetallic nanoparticles at each step of the procedure: BNP synthesis, aggregation and sensing in order to understand the sensing mechanism. To better understand colorimetric sensing of Co2+ using Ag-Au BNPs, various solution mixtures were analyzed by using SP-ICP-MS and FlFFF-ICP-MS. RESULTS: SP-ICP-MS provided the information on the core size, size distribution and particle number concentration, as well as the heterogeneity of the particles synthesized by using various citrate concentrations and metal ratios. FlFFF-ICP-MS offered the information on hydrodynamic size as well as the signal intensity ratio of Ag and Au in BNPs and for the understanding of the aggregation of BNPs arising from the [Co(II)(en)3]2+ complex surrounding the surface of the BNPs. Under optimum sensing condition, the use of SP-ICP-MS for BNPs assisted detection of Co2+ improved the sensitivity of Co2+ determination by 20-fold in comparison with the conventional spectrophotometric analysis. SIGNIFICANCE: The information obtained from SP-ICP-MS and FlFFF-ICP-MS can be combinedly used to understand sensing mechanism and to select the best condition for synthesis of BNPs used as sensor. This study illustrates the usefulness of SP-ICP-MS and FlFFF-ICP-MS in the nanoparticle-based sensor development research area.

Tailoring ZnO nanowire crystallinity and morphology for label-free capturing of extracellular vesicles.

Zinc oxide (ZnO) nanowires have shown their potential in isolation of cancer-related biomolecules such as extracellular vesicles (EVs), RNAs, and DNAs for early diagnosis and therapeutic development of diseases. Since the function of inorganic nanowires changes depending on their morphology, previous studies have established strategies to control the morphology and have demonstrated attainment of improved properties for gas and organic compound detection, and for dye-sensitized solar cells and photoelectric conversion performance. Nevertheless, crystallinity and morphology of ZnO nanowires for capturing EVs, an important biomarker of cancer, have not yet been discussed. Here, we fabricated ZnO nanowires with different crystallinities and morphologies using an ammonia-assisted hydrothermal method, and we comprehensively analyzed the crystalline nature and oriented growth of the synthesized nanowires by X-ray diffraction and selected area electron diffraction using high resolution transmission electron microscopy. In evaluating the performance of label-free EV capture in a microfluidic device platform, we found both the crystallinity and morphology of ZnO nanowires affected EV capture efficiency. In particular, the zinc blende phase was identified as important for crystallinity, while increasing the nanowire density in the array was important for morphology to improve EV capture performance. These results highlighted that the key physicochemical properties of the ZnO nanowires were related to the EV capture performance.

Luminescent nanohybrid of ZnO quantum dot and cellulose nanocrystal as anti-counterfeiting ink.

Luminescent quantum dot (QD) ink is currently a powerful tool for generating hidden information on paper substrates. Herein, we fabricated a nanohybrid ink of bacterial cellulose nanocrystal (BCNC) and UV-responsive ZnO QD via electrostatic self-assembly for improving solvent resistance and message encryption process. Under investigations on the printed areas, the nanohybrid can slightly infiltrate into the paper fibers and form a thin layer on the top of paper substrates, conferring an enhanced print permanence against wetting conditions while maintaining the daylight unobservability and its luminescent stability. The water resistance of the proposed nanohybrid ink enables developing a higher security level that the prints can be submerged in CuCl2 aqueous solutions to quench the luminescent message. The concealed message can eventually be revealed under UV light again after submerging in EDTA solution. Our ZnO QD/BCNC nanohybrid with eco-friendly nature therefore exhibits great potential as security marking ink for counterfeit protection with sustainable uses.

Highly branched gold-copper nanostructures for non-enzymatic specific detection of glucose and hydrogen peroxide.

The development of highly sensitive and highly selective sensors for non-enzymatic glucose and hydrogen peroxide (H2O2) detection using gold-copper alloy nanoparticles (AuCu alloy NPs) is reported. The AuCu NPs are nanostructures with branches and can be used as an electrochemical catalyst. Series of AuCu alloy NPs with various metal ratios are synthesized through a coreduction reaction. The morphology of AuCu alloy NPs is altered from highly branched structures (nanourchin, nanobramble, nanostar, nanocrystal) to a spherical shape by increasing Au content in the synthesis reaction. Cu-rich AuCu nanobramble and Au-rich AuCu nanostar exhibit selective electrocatalysis behaviors toward electro-oxidation of glucose and electroreduction of H2O2, respectively. The AuCu nanobramble-based sensor holds great potential in glucose detection with a linear working range of 0.25 to 10 mM. The sensor possesses a sensitivity of 339.35 µA mM-1 cm-2, a limit of detection (LOD) of 16.62 µM, which is an acceptable selectivity and good stability. In addition, the AuCu nanostar-based sensor shows excellent electrochemical responses toward H2O2 reduction with good selectivity, reproducibility, and a short response time of about 2-3 s. The linear range for H2O2 determination is 0.05 to 10 mM, with LOD and sensitivity of 10.93 µM and 133.74 µA mM-1 cm-2, respectively. The good sensing performance is a result of the synergistic surface structure and atomic composition effects, which leads AuCu alloys to be a promising nanocatalyst for sensing both glucose and H2O2. Graphical abstract Schematic illustration presents the construction of gold-copper alloy nanoparticles (AuCu alloy NPs) on the surface of screen-printed carbon electrode (SPCE). The highly branched nanostructures of AuCu alloys with different surface structure and metal ratios give selective electrocatalysis behaviors. Cu-rich AuCu nanobramble-based sensor reveals prominent electrocatalytic activity for glucose detection. Au-rich AuCu nanostar-based sensor provides good electrochemical response for H2O2 detection.

Silver nanoparticle/bacterial nanocellulose paper composites for paste-and-read SERS detection of pesticides on fruit surfaces.

This study aimed to develop an eco-friendly flexible surface-enhanced Raman scattering (SERS) substrate for in-situ detection of pesticides using biodegradable bacterial nanocellulose (BNC). Plasmonic silver nanoparticle- bacterial nanocellulose paper (AgNP-BNCP) composites were prepared by vacuum-assisted filtration. After loading AgNPs into BNC hydrogel, AgNPs were trapped firmly in the network of nanofibrous BNCP upon ambient drying process, resulting in 3D SERS hotspots within a few-micron depth on the substrate. The fabricated AgNP-BNCPs exhibited high SERS activity with good reproducibility and stability as demonstrated by the detection of 4-aminothiophenol and methomyl pesticide. Due to the optical transparency of BNCP, a direct and rapid detection of methomyl on fruit peels using AgNP-BNCPs can be achieved, demonstrating a simple and effective 'paste-and-read' SERS approach. These results demonstrate potential of AgNP-BNCP composites for user-friendly in-situ SERS analysis.

Alterations of mineralized matrix by lead exposure in osteoblast (MC3T3-E1) culture.

The present study investigated the effect of lead (Pb) on bone ultrastructure and chemistry using an in vitro bone model. MC3T3-E1 preosteoblasts were differentiated and treated with lead acetate at 0.4, 2, 10, and 50 µM. No abnormalities in either cell growth or bone nodule formation were observed with the treated dose of lead acetate. However, Pb treatments could significantly increase Pb accumulation in differentiated osteoblast cultures and upregulate expression of Divalent metal transporter 1 (Dmt1) in a dose dependent manner. Pb treatments also altered the expression of osteogenic genes, including secreted phosphoprotein 1, osteocalcin, type I collagen, and osteoprotegerin. Moreover, in mineralized osteoblast cultures, Pb was found to be mainly deposited as Pb salts and oxides, respectively. Ultrastructure analysis revealed Pb localizing with calcium and phosphorus in the mineralized matrix. In mineralizing osteoblast cells, Pb was found in the intracellular calcified vesicles which is one of the bone mineralization mechanisms. Pb was also present in mineral deposits with various shapes and sizes, such as small and large globular or needle-like mineral deposits representing early to mature stages of mineral deposits. Furthermore, Pb was found more in the globular deposits than the needle shaped mineral crystals. Taken together, our observations revealed how Pb incorporates into bone tissue, and showed a close association with bone apatite.

Disentangling cryptic species with isaria-like morphs in Cordycipitaceae.

A new genus and eight new species, all with isaria-like phialides, are described in Cordycipitaceae from Thailand. The new genus, Samsoniella, is segregated from Akanthomyces based on morphological and molecular evidence. Samsoniella differs from Akanthomyces in producing orange cylindrical to clavate stromata with superficial perithecia and orange conidiophores with isaria-like phialides and white to cream conidia. A new combination for CBS 240.32, originally identified as Paecilomyces farinosus (Isaria farinosa), and CBS 262.58, originally identified as Penicillium alboaurantium, respectively, is made in Samsoniella. Two new species, Samsoniella aurantia and S. inthanonensis, are described from lepidopteran larvae. Two new species of Cordyceps, C. blackwelliae and C. lepidopterorum, were also found on coleopteran and lepidopteran larvae. Both produce isaria-like morphs with globose phialides and attenuated long necks and white mycelium in culture. The authors established a sexual-asexual link for Cordyceps javanica (= Isaria javanica) on lepidopteran larvae. Four new species, Akanthomyces kanyawimiae, A. sulphureus, A. thailandicus, and A. waltergamsii, were pathogenic on spiders, with some strains of A. kanyawimiae also found on unidentified insect larvae. These four species of Akanthomyces occur on the underside of leaves and produce white to cream white powdery conidia, whereas S. aurantia and S. inthanonensis were found in leaf litter and produce bright orange stromata and synnemata with white conidia. Another new combination, Akanthomyces ryukyuensis, is proposed. Phylogenetic analyses based on a combined data set comprising the nuc rDNA region encompassing the internal transcribed spacers 1 and 2 along with the 5.8S rDNA (ITS), nuc 28S rDNA (28S), partial sequences of translation elongation factor 1-α gene (TEF1), and the genes for RNA polymerase II largest (RPB1) and second-largest (RPB2) subunits strongly support the delimitation of these new species of Cordyceps, Akanthomyces, and in a new genus Samsoniella in Cordycipitaceae.

Piezoelectric-Induced Triboelectric Hybrid Nanogenerators Based on the ZnO Nanowire Layer Decorated on the Au/polydimethylsiloxane-Al Structure for Enhanced Triboelectric Performance.

Here, we demonstrate a novel device structure design to enhance the electrical conversion output of a triboelectric device through the piezoelectric effect called as the piezo-induced triboelectric (PIT) device. By utilizing the piezopotential of ZnO nanowires embedded into the polydimethylsiloxane (PDMS) layer attached on the top electrode of the conventional triboelectric device (Au/PDMS-Al), the PIT device exhibits an output power density of 50 µW/cm2, which is larger than that of the conventional triboelectric device by up to 100 folds under the external applied force of 8.5 N. We found that the effect of the external piezopotential on the top Au electrode of the triboelectric device not only enhances the electron transfer from the Al electrode to PDMS but also boosts the internal built-in potential of the triboelectric device through an external electric field of the piezoelectric layer. Furthermore, 100 light-emitting diodes (LEDs) could be lighted up via the PIT device, whereas the conventional device could illuminate less than 20 LED bulbs. Thus, our results highlight that the enhancement of the triboelectric output can be achieved by using a PIT device structure, which enables us to develop hybrid nanogenerators for various self-power electronics such as wearable and mobile devices.

Efficiency of resveratrol-loaded sericin nanoparticles: Promising bionanocarriers for drug delivery.

Sericin protein nanoparticles are a biocompatible, bio-viable class of nanocarriers gaining prominence in drug delivery system. This research aimed to investigate the suitability fabrication of silk protein (SP) nanoparticles for loading with resveratrol (RSV) via a solventless precipitation technique. The addition of 0.5% (w/v) pluronic surfactant proved optimal for SP nanoparticle fabrication, with obtained nanoparticles being spherical, mono-dispersed and having mean size of approximately 200-400 nm. All exhibited negative surface charges, the extent of which being dependent on the SP concentration, and were non-toxic to normal skin fibroblasts (CRL-2522). Loading of RSV, a promising which poorly soluble multi-targeted anti-oxidative and anti-inflammatory natural polyphenol, into SP nanoparticles proved feasible, with encapsulation levels of 71-75% for 0.6% and 1.0% (w/v) nanoparticle formulations, respectively. Resveratrol-loaded SP nanoparticles strongly inhibited growth of colorectal adenocarcinoma (Caco-2) cells although proved non-cytotoxic to skin fibroblasts, as indicated by cell viability assays. Cellular internalization of SP nanoparticles proved facile and dependent on incubation time; transfection of these carriers, in vitro results indicating sustained release of RSV (over 72 h), and drug solubility enhancements on encapsulation highlight their potential in therapeutic and pharmaceutical applications. Thus, SP nanoparticles is a promising approach to be potential bio-nanocarrier for drug delivery system.

Phospholipid-chitosan hybrid nanoliposomes promoting cell entry for drug delivery against cervical cancer.

This study emphasizes the development of a novel surface modified liposome as an anticancer drug nanocarrier. Quaternized N,O-oleoyl chitosan (QCS) was synthesized and incorporated into liposome vesicles, generating QCS-liposomes (Lip-QCS). The Lip-QCS liposomes were spherical in shape (average size diameter 171.5±0.8nm), with a narrow size distribution (PDI 0.1±0.0) and zeta potential of 11.7±0.7mV. In vitro mucoadhesive tests indicated that Lip-QCS possesses a mucoadhesive property. Moreover, the presence of QCS was able to induce the cationic charge on the surface of liposome. Cellular internalization of Lip-QCS was monitored over time, with the results revealing that the cell entry level of Lip-QCS was elevated at 24h. Following this, Lip-QCS were then employed to load cisplatin, a common platinum-containing anti-cancer drug, with a loading efficiency of 27.45±0.78% being obtained. The therapeutic potency of the loaded Lip-QCS was investigated using a 3D spheroid cervical cancer model (SiHa) which highlighted their cytotoxicity and apoptosis effect, and suitability as a controllable system for sustained drug release. This approach has the potential to assist in development of an effective drug delivery system against cervical cancer.

Modified NLC-loaded coumarin for pharmaceutical applications: the improvement of physical stability and controlled release profile.

BACKGROUND: Coumarin-6 is a lipophilic dye and is often used as a model in delivery system. OBJECTIVE: The aim of this study was to improve the nonstructured lipid carrier (NLC) system loading with lipophilic molecule, coumarin-6, and to investigate its characteristics in terms of physical stability and controlled release profile. MATERIALS AND METHODS: Initially, the selection of the coating polymer was observed. Then, the preparation of the conventional NLC-loaded coumarin-6 was compared to the modified NLC-loaded coumarin-6 via the probe sonication. The physical properties and stability were determined by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. The release profile was established using fluorescent spectroscopic method. RESULTS AND DISCUSSION: The size and zeta potential measurement showed significant decrease in the size range of the modified NLC-loaded coumarin and the lower intensity of the surface charge compared to the NLC-loaded coumarin. The change of crystallinity observed from DSC and XRD techniques indicated the molecular dispersion of coumarin-6 in the lipid matrix of NLC. The FT-IR spectra were also proven that coumarin-6 was entrapped in the NLC molecule. The result showed comparable controlled release profile to the conventional preparation with no difference on the cytotoxicity level. CONCLUSIONS: The modified NLC delivery system, therefore, exhibited the acceptable potential as a nanocarrier.

Layer-by-layer engineered nanocapsules of curcumin with improved cell activity.

Nanocarriers based on electrostatic Layer-by-layer (LbL) assembly of CaCO3 nanoparticles (CaCO3 NPs) was investigated. These inorganic nanoparticles was used as templates to construct nanocapsules made from films based on two oppositely charged polyelectrolytes, poly(diallyldimethylammonium chloride), and poly (sodium 4-styrene-sulfonate sodium salt), followed by core dissolution. The naked CaCO3 NPs, CaCO3 NPs coated with the polyelectrolytes and hollow nanocapsules were found with hexagonal shape with average sizes of 350-400 nm. A reversal of the surface charge between positive to negative zeta potential values was found, confirming the adsorption of polyelectrolytes. The loading efficiency and release of curcumin were controlled by the hydrophobic interactions between the drug and the polyelectrolyte matrix of the hollow nanocapsules. The quantity of curcumin released from hollow nanocapsules was found to increase under acidic environments, which is a desirable for anti-cancer drug delivery. The hollow nanocapsules were found to localize in the cytoplasm and nucleus compartment of Hela cancer cells after 24 h of incubation. Hollow nanocapsules were non-toxic to human fibroblast cells. Furthermore, curcumin loaded hollow nanocapsules exhibited higher in vitro cell inhibition against Hela cells than that of free curcumin, suggesting that polyelectrolyte based-hollow nanocapsules can be utilized as new carriers for drug delivery.

Surface modification of PLGA nanoparticles by carbopol to enhance mucoadhesion and cell internalization.

Mucoadhesive poly (lactic-co-glycolic acid) (PLGA) nanoparticles having a modified shell-matrix derived from polyvinyl alcohol (PVA) and Carbopol (CP), a biodegradable polymer coating, to improve the adhesion and cell transfection properties were developed. The optimum formulations utilized a CP concentration in the range of 0.05-0.2%w/v, and were formed using modified emulsion-solvent evaporation technique. The resulting CP-PLGA nanoparticles were characterized in terms of their physical and chemical properties. The absorbed CP on the PLGA shell-matrix was found to affect the particle size and surface charge, with 0.05% CP giving rise to smooth spherical particles (0.05CP-PLGA) with the smallest size (285.90 nm), and strong negative surface charge (-25.70 mV). The introduction of CP results in an enhancement of the mucoadhesion between CP-PLGA nanoparticles and mucin particles. In vitro cell internalization studies highlighted the potential of 0.05CP-PLGA nanoparticles for transfection into SiHa cells, with uptake being time dependent. Additionally, cytotoxicity studies of CP-PLGA nanoparticles against SiHa cancer cells indicated that low concentrations of the nanoparticles were non-toxic to cells (cell viability >80%). From the various formulations studied, 0.05CP-PLGA nanoparticles proved to be the optimum model carrier having the required mucoadhesive profile and could be an alternative therapeutic efficacy carrier for targeted mucosal drug delivery systems with biodegradable polymer.