Monodisperse Nanoparticles Research Articles

Ag nanoparticles homogeneously anchored on kaolin synergistically improve the tribological performance of PBO/phenolic resin liner composites

In recent years, two dimensional hybrid materials have attracted immense attention in tribology field. However, kaolin shows potential value in catalysts and oil lubrication, and rarely in tribology of LC (liner composites). Herein, kaolin/Ag hybrids, in which mono-dispersed Ag nanoparticles (AgNPs) were dotted on kaolin, were prepared via in-situ reduction. The tribological behaviors of kaolin/Ag hybrids-reinforced PBO(poly(p-phenylene benzobisoxazole)/phenolic resin LC were evaluated. The results indicated that wear rate decreased but the friction coefficient slightly increased for sole kaolin filled PBO/phenolic resin LC. However, when kaolin/Ag hybrids were incorporated into PBO/phenolic resin LC, the wear rate and friction coefficient synchronously decreased. To understand the synergistic mechanism, worn surface morphology and a cross section of the tribofilm via FIB-TEM analyses are provided.

A Class of Biocompatible Dye-Protein Complex Optical Nanoprobes.

Molecular organic dyes are classic fluorescent nanoprobes finding tremendous uses in biological and life sciences. Yet, they suffer from low brightness, poor photostability, and lack of functional groups for bioconjugation. Here, we describe a class of biocompatible dye-protein optical nanoprobes, which show long-time photostability, superbrightness, and enriched functional groups. These nanoprobes utilize apoferritin (an intracellular protein for iron stores and release) to encase appropriate molecular organic dyes to produce on-demand fluorescence in aqueous solution. A pH-driven dissociation-reconstitution process of apoferritin subunits allows substantial incorporation of hydrophilic (aggregation caused quenching, ACQ) or hydrophobic (aggregation induced enhancement, AIE) dye molecules into the protein nanocavity (8 nm), producing monodispersed dye-apoferritin nanoparticles (apo-dye-NPs, ∼12 nm). As compared with single dye monomer, single apo-dye-NPs possess hundreds of times larger molar extinction coefficient and 2 orders of magnitude higher absolute luminescence quantum yield (up to 45-fold), multiplying fluorescence brightness up to 2778-fold. We show that varying the type of incorporated dyes entails a precise control over nanoprobe emission profile tunable in a broad spectral range of 370-1300 nm. Mechanical investigations indicate that the diversified microstructures of nanocavity inner surface are able to conform ACQ dyes at reasonable space interval while providing protein-guided-stacking for AIE dyes, thus enhancing fluorescence quantum yield through confining intermolecular quenching and intramolecular rotation. Moreover, apo-dye-NPs are able to emit stable fluorescence (over 13 min) without quenching in confocal imaging of HepG2 cancer cell under ultrahigh laser irradiance (1.3 × 106 W/cm2). These superb properties make them suitable, as demonstrated in this work, for long-term super-resolved structured illumination microscopic cell imaging (spatial resolution, 117 nm) over 48 h, near-infrared (NIR) fluorescence angiography imaging of whole-body blood vessels (spatial resolution, 380 μm), and NIR photoacoustic imaging of liver in vivo.

Green-monodispersed Pd-nanoparticles for improved mitigation of pathogens and environmental pollutant

This research, for the first time, demonstrates the synthesis of a novel double chain amphiphilic metallosurfactant complex i.e., bisdecanoatopalladium (II) (complex 1) which provides a template to fabricate monodispersed palladium nanoparticles (Pd NPs). Complex 1 was characterized using CHN, Mass, NMR and FTIR techniques. Complex 1 formed inverted metallomicelles (IMMs) in various n-alcohols and DCM at very low critical aggregation concentration (CAC), (1.19–1.65 × 10−4 M) estimated using conductivity studies. IMMs-supported greener synthesis of Pd NPs suggests the localized and controlled reduction of metalloaggregates and arrested growth of Pd NPs confined in the cavity of IMMs. UV–vis, XRD, HRTEM and DLS techniques have provided a detailed insight into the structure, morphology and dispersibility of as-obtained Pd NPs. The uniform surfactant coating enables the synthesis of highly monodispersed and spherical Pd NPs in a very narrow size of 1–2 nm. This green approach eliminates the existing challenges of controlling size, shape, and dispersibility. The superiority of Pd NPs has been explored in terms of catalytic and biological applications. The Pd NPs are found to be extremely selective, efficient, and eco-friendly and recyclable catalysts for the reduction of para-nitrophenol (PNP) with an achievable rate constant as high as 1.018 min−1 with mere 2 mol% catalyst dose. Pd NPs also exhibit excellent binding ability with BSA protein exhibiting a high binding constant of 9.7 × 105 M−1. Besides, Pd NPs can be promoted as excellent therapeutic agents as they have shown noteworthy (i) antimicrobial activity against pathogenic microbes i.e., Bacillus cereus ITCC 240 (MIC 0.002 μg/mL), Klebsiella pneumoniae ITCC 138 (MIC 0.003 μg/mL) and Curvularia lunata ITCC 6257 (MIC 0.001 μg/mL) and (ii) anticancer activity against human liver cancer cells i.e., HepG2 (IC50 25 μg/mL). The outcomes of this research epitomize Pd NPs as a potential green nano-system having broader prospective in catalytic and biological applications.

Porphyrin‐Based Nanostructures for Cancer Theranostics: Chemistry, Fundamentals and Recent Advances

AbstractAs heterocyclic macrocycle organic compounds, porphyrins can generate a rich platform of chemical behavior and characteristics conveniently utilized for multiple bioapplications, including bio‐sensors, fluorescence tracking, and in vivo imaging. The conjugation of nanotechnology and porphyrins presents a promising approach to enhance the safety and effectiveness of porphyrin‐based materials in phototherapy against cancer. Several nanoformulations, including organic and inorganic nanocarriers, porphyrin‐laden nanoparticles, porphyrin‐based amphiphilic molecules, supramolecular polymers, and porphyrin‐based block copolymers, have been investigated to deliver porphyrins, which protect the pre‐mature release of photosensitizer and provide tumor‐selective and site‐specific targeting. The monodisperse nanoparticles formed of biocompatible building block conjugates can be beneficially used to develop a multifunctional novel system utilized in optical imaging, positron emission tomography, photodynamic therapy, photothermal therapy, and other imaging modalities in one formulation. This topic is important because exploiting and knowing porphyrin‐based nanostructures aids in detecting pathological damages that cannot readily be discovered by routine imaging or physical examination and thus, helps early diagnosis of cancer. This critical review will assess the basic knowledge and updated information for a broad audience of scientists, engineers, and newcomers related to the porphyrin‐based nanostructures for cancer theranostics

WO3/C nanoarchitectures assembled with 1D nanowires: The synthesis, Pt nanoparticles decoration, and highly enhanced hydrogen evolution in neutral media

Electrochemical water splitting is an efficient approach to produce green hydrogen, while it is still very challenging to design of highly efficient WO3-based hydrogen evolution reaction (HER) catalysts especially those in neutral media. Here, 3D WO3/C nanoarchitectures assembled by 1D nanowires were prepared through water-oil two-phase microemulsion method and subsequent annealing treatment. The monodispersed Pt nanoparticles were loaded onto the WO3/C nanoarchitectures. A series of WO3/C composites were produced via modulating the addition of Pt salt. The optimum 2 Pt@WO3/C catalyst exhibited an overpotential of 149 mV at 10 mA cm−2 in neutral media, which was the first reported about the WO3-based materials and much better than most catalysts reported in literatures by far. Interestingly, the HER activity of 2 Pt@WO3/C was much higher than commercial Pt/C at high overpotential range (>260 mV). Density functional theory results demonstrated that the more toilless HER process could be attributed to the enhanced carrier densities, the electron transfer between Pt and W atoms, and the lowered energy barrier for water dissociation and H* desorption.

Microfluidics Technology for the Design and Formulation of Nanomedicines.

In conventional drug administration, drug molecules cross multiple biological barriers, distribute randomly in the tissues, and can release insufficient concentrations at the desired pathological site. Controlling the delivery of the molecules can increase the concentration of the drug in the desired location, leading to improved efficacy, and reducing the unwanted effects of the molecules under investigation. Nanoparticles (NPs), have shown a distinctive potential in targeting drugs due to their unique properties, such as large surface area and quantum properties. A variety of NPs have been used over the years for the encapsulation of different drugs and biologics, acting as drug carriers, including lipid-based and polymeric NPs. Applying NP platforms in medicines significantly improves the disease diagnosis and therapy. Several conventional methods have been used for the manufacturing of drug loaded NPs, with conventional manufacturing methods having several limitations, leading to multiple drawbacks, including NPs with large particle size and broad size distribution (high polydispersity index), besides the unreproducible formulation and high batch-to-batch variability. Therefore, new methods such as microfluidics (MFs) need to be investigated more thoroughly. MFs, is a novel manufacturing method that uses microchannels to produce a size-controlled and monodispersed NP formulation. In this review, different formulation methods of polymeric and lipid-based NPs will be discussed, emphasizing the different manufacturing methods and their advantages and limitations and how microfluidics has the capacity to overcome these limitations and improve the role of NPs as an effective drug delivery system.

Gold nanoparticles-loaded contact lenses for laser protection and Meibomian Gland Dysfunction (MGD) dry eye treatment

Laser based devices are ubiquitous in many fields which has resulted in an increase in ocular injuries from laser exposure. Glasses for laser protection are available but contact lenses that block certain wavelengths could be a less bulky alternative. Here, we focus on developing a contact lens for protecting eyes from accidental exposure to a green laser by incorporation of gold nanoparticles that exhibit a local maximum in absorbance as a tunable wavelength due to the localized surface plasmon resonance (LSPR) effect. The particles are incorporated in a poly vinyl alcohol (PVA) contact lens because PVA offers the twin benefits of stabilizing gold nanoparticles during manufacturing by Turkevich method and excellent biocompatibility and high-water content. The monodispersed gold nanoparticles of the desired size (11.75 ± 1.09 nm) were prepared by Turkevich method with PVA as the stabilizer. The particles were separated out by anti-solvent precipitation and then redispersion to achieve the desired concentration, and finally crosslinked by freezing-thawing cycling to form a PVA lens loaded with gold nanoparticles (PVA GoldinLens). The gold nanoparticles remain well-dispersed in the lens for all gold nanoparticle loadings (0%, 0.25%, 0.5%, 1%, 2% and 4%, wt% in dried lenses). The transmittance spectra of the PVA GoldinLenses exhibit a minimum at 520 nm due to the LSPR effect of the 12 nm gold nanoparticles. The transmittance was reduced in the entire wavelength range, as is typical in laser protection glasses but the decrease is more pronounced around 520 nm. The laser protection efficacy enhances with particle concentration but becomes relatively independent of particle loading at higher concentration reaching a maximum value of 66.7%. To further improve the laser protection, we explore an alternative approach of manufacturing the gold particles inside two commercial contact lenses (Acuvue TruEye and Moist) by soaking the lenses in gold precursor solution (0.25–1%, wt%) followed by reduction by soaking in solution of 5% (wt%) sodium borohydride to form the particles. This process leads to formation of about 100 nm size particles in the lenses. Incorporation of particles in both commercial lenses offers superior absorption compared to the PVA lens at comparable loadings with > 90% blocking of laser at about 3% (wt% in dried lens) loading. However, the absorbance is not tuned to the green laser due to the larger particle sizes and particle aggregates which result in light transmittance decreasing significantly in the entire wavelength range. Based on comparing the absorption spectra and laser blocking of the lenses with commercial laser blocking glasses, the TruEye GoldinLens with 0.75% particles appears to be a good potential alternative. In all cases, absorption of laser leads to localized heating which could damage tissue but on the other hand could potentially also be useful in treating indications in which warming eyelids is beneficial such as dry eyes. Laser exposure increases temperature to higher than the melting point of the meibomian lipids which is critical for treating the gland dysfunction (MGD) dry eye disease by local heating. This work advances the field of incorporation of gold nanoparticles in contact lenses and other similar gels for a broad set of applications including laser-protection, and treatment of dry eyes and color blindness.

Self-Terminated Electroless Deposition of Surfactant-Free and Monodispersed Pt Nanoparticles on Carbon Fiber Microelectrodes for Sensitive Detection of H2O2 Released from Living Cells.

We report a self-terminated electroless deposition method to prepare surfactant-free and monodispersed Pt nanoparticle (NP)-modified carbon fiber microelectrodes (Pt NP/CFEs) for electrochemical detection of hydrogen peroxide (H2O2) released from living cells. The surfactant-free and monodispersed Pt NPs with a uniform size of 65 nm are spontaneously deposited on a CFE surface by immersing an exposed carbon fiber (CF) of CFE in the PtCl42- solution, in which an exposed CF can be used as the reducing agent and stabilizer. A self-terminated electroless deposition method is demonstrated, in which the density and size of Pt NPs on a CFE surface do not increase when the reaction time increases from 20 to 60 min. The self-terminated electroless deposition process not only can effectively avoid any manual electrode modification and thus largely minimize person-to-person and electrode-to-electrode deviations but also can avoid the use of any extra reductant or surfactant in the fabrication process. Therefore, Pt NPs/CFEs, with good reproducibility and sensitivity, not only exhibit high electrocatalytic activity toward the oxidation of H2O2 but also maintain the spatial resolution of CFEs. Moreover, Pt NPs/CFEs can detect H2O2 with a wide linear range of 0.5-80 μM and a low detection limit of 0.17 μM and then can be successfully applied in the monitoring of H2O2 released from RAW 264.7 cells. The self-terminated electroless deposition method can also be extended to selectively prepare other metal NP-modified CFEs, such as Au NPs/CFEs or Ag NPs/CFEs, by choosing the metal ions with higher reduction potential as precursors. This work provides a simple, straightforward, and general method for the preparation of small, surfactant-free, and monodispersed metal NP-modified CFEs with high sensitivity, reproducibility, and spatial resolution.

Physicochemical characterization of Amine-functionalized Bio-nanosilica extracted from rice husk ash as a platinum support

Bio-nanosilica (bio-SiO2) from rice husk ash (RHA) has attracted interest as a sustainable material that can be used as a catalyst support for various applications. Pt supported on bio-SiO2 (Pt/SiO2) shows the potential for application as a non-carbon based support for fuel cell catalysts. In this work, bio-SiO2 and Pt/SiO2 were synthesized, and their physicochemical properties were characterized. The temperature of rice husk combustion was varied from 700 °C to 800 °C for 1 h prior to alkaline precipitation to produce bio-SiO2. The results of field emission scanning electron microscopy showed that the bio-SiO2 prepared at 800 °C formed vivid monodispersed nanoparticles with sizes of 20–40 nm. Amine functionalization was performed prior to the anchorage of Pt nanoparticles at different Pt/SiO2 ratios. X-ray diffraction and energy dispersive X-ray analyses revealed that Pt had been successfully anchored onto bio-SiO2. The optimal Pt-to-SiO2 ratio was 1:2. Pt nanoparticles were uniformly distributed over the functionalized bio-SiO2. Other samples demonstrated Pt agglomeration on certain areas of bio-SiO2 and were thus not useful as electrocatalysts for the electrochemical reaction in fuel cells.

Degradation of bisphenol S by peroxymonosulfate activation through monodispersed CoFe2O4 nanoparticles anchored on natural palygorskite

• Monodispersed CoFe 2 O 4 nanoparticles anchored on palygorskite to activate PMS. • 16%-CFO@PAL/PMS oxidation system can effectively degrade BPS in water. • 16%-CFO@PAL composite exhibits high activity and low metal leaching property. • SO 4 · - and 1 O 2 mainly contributed degradation of BPS in 16%-CFO@PAL/PMS system. • Fe-O-Al bond between CoFe 2 O 4 and PAL improved the stability of 16%-CFO@PAL. Bisphenol S (BPS) has been detected frequently in water bodies, which poses a serious threat to human health and the environment. The sulfate radical-based advanced oxidation process is considered as a promising water purification technology by activating peroxymonosulfate (PMS). However, a catalyst with low metal leaching rate and high effective catalytic ability is needed to activate PMS. In this study, natural clay of palygorskite (PAL) was used to mediate monodispersed CoFe 2 O 4 nanoparticles to degrade BPS by PMS activation. The monodispersed CoFe 2 O 4 nanoparticles were distributed and anchored on the surface of PAL, which caused the 16%-CoFe 2 O 4 @PAL (16%-CFO@PAL) composite expose more reaction sites, thus exhibiting excellent catalytic performance. A satisfactory BPS removal rate (> 99%) was obtained by introducing 50 mg L -1 16%-CFO@PAL and 0.16 mM PMS. The interaction mechanism between CoFe 2 O 4 nanoparticles and PAL was discussed. The Al-O-Fe bond between CoFe 2 O 4 nanoparticles and PAL endowed the 16%-CFO@PAL composite with low metal leaching property, high stability and reusability. SO 4 ·- and 1 O 2 played a dominant role in the degradation of BPS. The generation mechanism of reactive species was proposed. The influences of various degradation parameters (e.g., catalyst dosage, PMS concentration, initial solution pH, and BPS concentration) and water constituents (e.g., inorganic anions and NOM) on the degradation of BPS were investigated. Based on the identified intermediates and density functional theory (DFT) calculations, the possible degradation pathways of BPS were discussed. This study provides a new idea for the preparation of high-efficiency natural clay-based PMS catalysts for water purification.

Green synthesis and properties of silver nanoparticles in sulfobutylether-β-cyclodextrin aqueous solution

Spherical and monodisperse silver nanoparticles (AgNPs) were obtained in aqueous solution at neutral pH in the presence of sulfobutylether-β-CD (SBE-βCD) by using an eco-friendly approach. Their stability and size were determined by spectroscopic analysis and light scattering measurements. The SBE-βCD molecules are highly distributed around the AgNPs as observed in the SEM-EDX images and tend to act as stabilizers by preventing their aggregation in solution as suggested by the zeta potential measurements. Furthermore, the dissolution of the investigated nanoparticles was tested by oxidation in the Fenton-like reaction.

Effects of Process Variables on Properties of CoFe2O4 Nanoparticles Prepared by Solvothermal Process

Controlling the morphology and magnetic properties of CoFe2O4 nanoparticles is crucial for the synthesis of compatible materials for different applications. CoFe2O4 nanoparticles were synthesized by a solvothermal method using cobalt nitrate, iron nitrate as precursors, and oleic acid as a surfactant. The formation of CoFe2O4 nanoparticles was systematically observed by adjusting synthesis process conditions including reaction temperature, reaction time, and oleic acid concentration. Nearly spherical, monodispersed CoFe2O4 nanoparticles were formed by changing the reaction time and reaction temperature. The oleic acid-coated CoFe2O4 nanoparticles inhibited the growth of particle size after 1 h and, therefore, the particle size of CoFe2O4 nanoparticles did not change significantly as the reaction time increased. Both without and with low oleic acid concentration, the large-sized cubic CoFe2O4 nanoparticles showing ferromagnetic behavior were synthesized, while the small-sized CoFe2O4 nanoparticles with superparamagnetic properties were obtained for the oleic acid concentration higher than 0.1 M. This study will become a basis for further research in the future to prepare the high-functional CoFe2O4 magnetic nanoparticles by a solvothermal process, which can be applied to bio-separation, biosensors, drug delivery, magnetic hyperthermia, etc.

Deposition of Ag nanoparticles on polydopamine-functionalized CNTs for improving the tribological properties of PPESK composites

In this study, CNTs were first modified by polydopamine (PDA) to facilitate their surface activation and then Ag nanoparticles were in-situ grown on CNT-PDA to obtain CNT-PDA/Ag. The effects of functionalized CNTs on the tribological behaviors of poly (phthalazinone ether sulfone ketone) (PPESK) were investigated. Results revealed that PDA layer could not only increase the active functional groups on the CNT surface, but also act as an activated platform for the deposition of mono-dispersed Ag nanoparticles. The decoration of Ag nanoparticles decreased the interaction among CNTs, which was conducive to their good dispersion. Besides, by filling 0.3 wt% CNT-PDA/Ag, the thermal properties of PPESK were significantly improved, and its friction-reduction and anti-wear performances were the best among all PPESK composites, due to the good interfacial interaction between CNTs and PPESK, the synergistic reinforcing and lubricating effect of CNTs and Ag nanoparticles, as well as the lubricating effect of transfer film.

Monodisperse Porous Carbon Nanospheres with Ultra‐High Surface Area for Energy Storage in Electrochemical Capacitors

AbstractHighly porous carbon nanoparticles are very suitable materials for supercapacitor electrodes due to their combination of large surface area for ion adsorption and short pathways for fast ion diffusion. Herein we describe the synthesis of highly porous carbon nanospheres (d=90 nm) by a simple strategy that involves the preparation of monodisperse nanoparticles by the oxidative polymerization of pyrrole, followed by their direct chemical activation with KHCO3. The morphology of the nanospheres is well retained after activation, and the inorganic impurities are removed by a simple washing step with water. The porous nanospheres possess a high electrical conductivity and specific surface areas exceeding 3000 m2 g−1 due to their high content of micropores and small mesopores (<4 nm). Their highly developed and readily available porosity make these materials promising for use as supercapacitor electrodes. In the aqueous 1 M H2SO4 electrolyte, the porous nanospheres reach a capacitance of 262 F g−1 and withstand an ultrahigh current density of 80 A g−1 maintaining a capacitance above 100 F g−1. In the organic 1 M TEABF4/AN and EMImTFSI/AN electrolytes, the nanoparticles reach 175 and 155 F g−1, and the supercapacitors could be cycled up to 50 A g−1 delivering 30 Wh kg−1 at a power density of 20 kW kg−1 and 31 Wh kg−1 at a power density of 31 kW kg−1, respectively. These results demonstrate the potential of these nanoparticles for energy storage applications.

Antimicrobial and antioxidant therapy with bioactive plant molecules on Fe3O4 phytohybrid nanoplatforms

BackgroundNanobiomedicines have gained increasing attention for their potential to improve efficacy and are emerging as a promising therapeutic paradigm. Magnetic nanoconjugates loaded with bioactive drugs have the advantage of sustained circulation in the bloodstream and significantly reduced toxicity of therapeutic agents in a precise manner. The well-developed surface chemistry of Fe3O4 has led to the development better tools, promoting them as nanoplatforms with potential technological applications in biomedical sciences.ResultsFe3O4 phytohybrids with Laxmitaru extract as the primary coating and loaded with Eugenol and Ylang-Ylang essential oils were successfully synthesized. The X-ray diffraction technique has revealed the high purity nanoparticle materials, as no additional impurity peaks were observed. Fourier transform infra-red spectra have confirmed the presence of a primary coating of Laxmitaru extract and a secondary layer of essential oil, as additional peaks and broadening are observed in drug-loaded Fe3O4 nanoparticles. Magnetic susceptibility values indicate the material's superparamagnetic nature. Transmission electron microscopy images have ensured that the particles were spherical, monodispersed, and in the range of 4.30 nm to 13.98 nm. Antimicrobial studies show inhibition zones on the microorganisms S. Aureus and E. Coli with enhanced activity. Drug entrapment efficiency studies revealed the encapsulation of drug molecules onto Fe3O4-Laxmitaru composite. Dynamic light scattering studies confirm the increase in hydrodynamic size, indicating the loading of essential oils and the decrease in polydispersity index ensures monodispersed nanoparticles. The antioxidant study showed the essential oils retained their antioxidant activity even after they were conjugated on Fe3O4-Lax composites.ConclusionsLaxmitaru phytochemical-coated Fe3O4 nanoparticles were successfully conjugated with Eugenol and Ylang-Ylang essential oils. Our results provide a model therapeutic approach for the development of new alternative strategies for enhancing antimicrobial and antioxidant therapy, with potential advantages in the field of nanobiomedicine.

Study on Nucleation and Growth Mechanism of Electrodeposited Pt-Ni Alloy

Pt-M (M=Ni, Co, Fe, et.al) alloy nanoparticle catalysts have been proved to be effective oxygen reduction reaction (ORR) catalysts with reduced Pt loading in proton exchange membrane fuel cells (PEMFCs). Electrodeposition methods have shown potential application on large-scale preparation of Pt catalysts by simplifying the synthetic settings as well as high controllability1,2. While their performance is unsatisfied due to the over-large particles and the difficulty of Pt-M co-deposition in aqueous solution. We herein modified the current electrodeposition method by switching aqueous electrolyte to water-soluble N, N-Dimethylformamide (DMF) for electrochemically co-depositing Pt-Ni alloy nanoparticles. Highly monodispersed Pt-Ni alloy nanoparticles are directly deposited on carbon substrate (Pt-Ni/C) via a facile potentiostatic technique from the selected DMF solution system and show promising specific activity towards ORR. Physiochemical characterizations, electrochemical tests and computational evaluations via density functional theory (DFT) were applied to uncover the internals of formation of highly monodispersed nanoparticles as well as the nucleation and growth of Pt-Ni nanoparticles. Our finding provides a hopeful extended Pt-M catalyst layer production strategy for PEMFCs and a new idea for the nucleation and growth mechanism for electrodeposited Pt-M alloy. Keywords: electrodeposition, Pt-Ni alloy nanoparticles, nucleation and growth mechanism, density functional theory Reference [1] A.J. Martín, A.M. Chaparro, M.A. Folgado, B. Gallardo, L. Daza, ECS Transactions, 2008, 13, 13.[2] P. Dhanasekaran, K. Lokesh, P.K. Ojha, A.K. Sahu, S.D. Bhat, D. Kalpana, Journal of Colloid and Interface Science, 2020, 572, 198. Acknowledgements This work was supported in part by National Natural Science Foundation of China (21975157) and the National Key Research and Development Program of China (2016YFB0101201 and 2016YFB0101312). Figure 1

Decoration of Graphenated Carbon Nanotube Electrodes with Platinum Nanoparticles via Atomic Layer Deposition

Platinum electrodes are commonly used in devices such as fuel cells, neurostimulators, and sensors. Device performance can be improved by increasing the electrochemically active surface area of the platinum, which increases the charge storage capacitance, oxygen reduction reaction (ORR) rates, and catalytic activity. Therefore, there is significant motivation to fabricate platinum 3D structures, but it is challenging to accomplish successfully. In this study, graphenated carbon nanotubes (gCNTs), a type of carbon nanotube with leaf-like graphene foliates, were decorated with platinum nanoparticles to fabricate a 3D structure with increased Pt surface area. The carbon nanotubes act as a conductive scaffold and the foliates provide increased surface area and highly reactive edge sites.The development of gCNTs was accomplished by systematically adjusting growth parameters in a microwave plasma enhanced chemical vapor deposition system. The primary growth parameters were growth temperature, growth time, process gas composition (methane flow rate vs ammonia flow rate), and microwave power. gCNTs were characterized to obtain the best relevant electrochemical properties, i.e., impedance, voltage window, stability, and charge storage capacity. Compared to platinum, typical gCNT electrodes had lower impedance at 100 Hz at 230 Ω vs 375 Ω for Pt. The electrochemical properties of the gCNTs were compared to scanning electron microscope images (Fig. 1) and it was found that a medium foliate density (3.0 CH4: 1 NH3) had the best electrochemical properties.Next, the gCNTs electrodes can be further enhanced by decoration with nanoparticles of platinum via atomic layer deposition (ALD). Atomic layer deposition alternates two reagents so that the first adsorbs on the surface in a monolayer and the second reacts with the monolayer. The most reactive sides tend to nucleate first, so that at low deposition density, particles preferentially deposit at the edges of the graphene foliates. A major advantage of ALD is that it produces much more monodispersed nanoparticles, which yields more uniform properties. The combined electrodes will have the larger electrochemical surface area of gCNTs and the catalytic and charge storage properties of platinum electrodes. Electrochemical properties of Pt-gCNTs will be compared to gCNTs and planar Pt electrodes. Figure 1

Development of topical eye-drops of lactoferrin-loaded biodegradable nanoparticles for the treatment of anterior segment inflammatory processes

Ocular inflammation is one of the most common comorbidities associated to ophthalmic surgeries and disorders. Since conventional topical ophthalmic treatments present disadvantages such as low bioavailability and relevant side effects, natural alternatives constitute an unmet medical need. In this sense, lactoferrin, a high molecular weight protein, is a promising alternative against inflammation. However, lactoferrin aqueous instability and high nasolacrimal duct drainage compromises its potential effectiveness. Moreover, nanotechnology has led to an improvement in the administration of active compounds with compromised biopharmaceutical profiles. Here, we incorporate lactoferrin into biodegradable polymeric nanoparticles and optimized the formulation using the design of experiments approach. A monodisperse nanoparticles population was obtained with an average size around 130 nm and positive surface charge. Pharmacokinetic and pharmacodynamic behaviour were improved by the nanoparticles showing a prolonged lactoferrin release profile. Lactoferrin nanoparticles were non-cytotoxic and non-irritant neither in vitro nor in vivo. Moreover, nanoparticles exhibited significantly increased anti-inflammatory efficacy in cell culture and preclinical assays. In conclusion, lactoferrin loaded nanoparticles constitute a safe and novel nanotechnological tool suitable for the treatment of ocular inflammation.

Are Plant-Based Carbohydrate Nanoparticles Safe for Inhalation? Investigating Their Interactions with the Pulmonary Surfactant Using Langmuir Monolayers.

Nanoparticle carriers show promise for drug delivery, including by inhalation, where the first barrier for uptake in the lungs is the monolayer pulmonary surfactant membrane that coats the air/alveoli interface and is critical to breathing. It is imperative to establish the fate of potential nanocarriers and their effects on the biophysical properties of the pulmonary surfactant. To this end, the impact of the nanoparticle surface charge on the lateral organization, thickness, and recompressibility of Langmuir monolayers of model phospholipid-only and phospholipid-protein mixtures was investigated using native and modified forms of nanophytoglycogen, a carbohydrate-based dendritic polymer extracted from corn as monodisperse nanoparticles. We show that the native (quasi-neutral) and anionic nanophytoglycogens have little impact on the phase behavior and film properties. By contrast, cationic nanophytoglycogen alters the film morphology and increases the hysteresis associated with the work of breathing due to its electrostatic interaction with the anionic phospholipids in the model systems. These findings specifically highlight the importance of surface charge as a selection criterion for inhaled nanoformulations.

Hollow CeO2 with ROS-Scavenging Activity to Alleviate Colitis in Mice.

IntroductionExcessive production of reactive oxygen species (ROS) to induce high oxidative stress is one of the main causes of colitis; thus, it has been regarded as a therapeutic target for colitis treatment. And the nanomaterial-based therapeutic strategies are effective against colitis. However, the previous elaborately designed materials exhibit limited application due to the uncertain biocompatibility and complicated manufacturing processes.MethodsIn this study, the highly monodisperse hollow CeO2 nanoparticles (H-CeO2) with uniform morphology were obtained by in situ growing CeO2 on solid silica nanoparticles and subsequently removing the silica core. The H-CeO2 was further modified with PEG, which owned excellent biological stability and biocompatibility. The experimental model of colitis induced by dextran sulfate sodium (DSS) was used to investigate the anti-inflammatory effect of H-CeO2-PEG.ResultsThe H-CeO2-PEG showed good ROS scavenging efficacy and decreased the levels of proinflammatory cytokines (IL-6, IL-1β, IL-18, and TNF-α) in DSS-induced colitis mice. Furthermore, H-CeO2-PEG inhibited the activation of the MAPK signalling pathway to alleviate colitis.ConclusionThis study reveals the therapeutic effects of CeO2-based nanomedicine toward colitis and elucidates the specific signalling pathway involved, which provides potential alternative therapeutic options for patients with inflammation tissue.