EFFECTS OF GELATIN AND GLUTARALDEHYDE CONCENTRATIONS ON CHARACTERISTICS OF CANTIGI (Vaccinium Varingiaefolium Miq.) EXTRACT LOADED GELATIN NANOPARTICLES AS ANTIOXIDANT

Cantigi is an endemic plant of sub-alpine area of Mount Tangkuban Parahu in Bandung, Indonesia. Previous study showed ethanol extract of young red leaves had antioxidant activity, however no information on this activity if changed into nanoparticles. The purpose of this study was to determine the effects of gelatin and glutaraldehyde concentrations on the characteristics of Cantigi extract loaded gelatin nanoparticles and to evaluate the antioxidant activity of nanoparticles. Cantigi leaves were extracted by maceration using n-hexane, ethyl acetate, and ethanol 96%. The ethanol extract was dried, made into nanoparticles by varying gelatin (0.1; 0.2; and 0.3 g) and glutaraldehyde (0.1; 0.2; and 0.3 mL) amounts, and conducted at 500 rpm and 40 °C for 3 hours. Nanoparticles were evaluated for particle size, zeta potential, morphology, and antioxidant activity. Nanoparticles with glutaraldehyde amount variation had particle sizes (PS) of 105.9±26.2; 37.1±8.7; and 32.5±7.4 nm; polydispersity indeces (PI) of 0.508; 0.717; and 0.563; zeta potential values (ZPV) of 0.55; 0.89; and 0.78 mV; and antioxidant activities (IC50) of 56.15±0.16; 53.67±0.10; and 51.57±0.39 ppm, respectively. Then, nanoparticles with gelatin amounts variation had PS of 22.5±5.1; 37.1±8.7; and 83.3±21 nm; PI of 0.604; 0.717; 0.326; ZPV of 1.27; 0.89; 0.18 mV; and antioxidant activities of 51.58±0.19; 53.67±0.12; and 55.46±0.04 ppm, respectively. Nanoparticle morphology was spherical. Cantigi leaf extract can be made into gelatin nanoparticles; the smaller the concentration of the polymer used and higher the concentration of the glutaraldehyde, the smaller the resulted particle size and increased antioxidant activity. Antioxidant activities of nanoparticles was lower than those of the extract (IC50 16.84±0.30 ppm).

Tuning the Dielectric Response in a Nanocomposite Material through Nanoparticle Morphology

The introduction of metal cluster dopants and molecular-scale inclusions in metal oxide matrices provides an opportunity for exploring new high-k solid-state dielectrics with tunable response. The quantum properties of molecular nanoparticles depend strongly on their size and shape, a characteristic that can be exploited in changing the response properties of a material, while the small nanoparticle size can help limit the usual issues of conduction and leakage. Here, we model the polarization of molecular-scale silver inclusions in magnesium oxide, using the Modern Theory of Polarization and Car-Parinello Molecular Dynamics (CPMD). Several trends are considered, including nanoparticle size, shape and orientation relative to the applied field. Dielectric permittivity enhancements of 30-100% were observed with inclusion sizes varying from 8 to 32 atoms, considering both rod-like and disk-like inclusions, with alignment either parallel or perpendicular to the external field. Currents calculated using the modern theory of polarization with periodic boundary conditions can experience box edge jumps due to the distortion of the matrix during the simulations - an approach for addressing these issues in CPMD calculations is outlined within.

Integrated high-throughput small RNA and transcriptome sequencing unveil the shape-dependent toxicity of nano-alumina in rat astrocytes

Background The large-scale applications of alumina nanoparticles (Al2O3-NPs), one of the most important NPs in the global market, are causing severe damages to the environment and human health. Our previous research has revealed a critical role of nanoparticle morphology (e.g., flake and rod) in determining the toxic potencies of Al2O3-NPs, where nanorods demonstrated a significantly stronger toxic response than that of nanoflakes. However, their underlying mechanisms have not been completely elucidated yet. In the present study, we evaluated and compared the potential toxicological mechanisms of two shapes of γ-Al2O3-NPs (flake versus rod) by measuring miRNA and mRNA profiles of astrocytes in rat cerebral cortex, ex vivo. Results A total of 269 mRNAs and 122 miRNAs, 180 mRNAs and 116 miRNAs were differentially expressed after nanoflakes or nanorods exposure, respectively. Among them, 55 miRNAs (e.g., miR-760-5p, miR-326-3p, and miR-35) and 105 mRNAs (e.g., Kdm4d, Wdr62, and Rps6) showed the same trend between the two shapes. These miRNAs and mRNAs were mainly involved in apoptosis, inflammatory pathways (e.g., NF-kappa B), carcinogenic pathways (e.g., MAPK, p53, Notch, Rap1, and Ras), and cellular lipid metabolisms (e.g., glycerolipid metabolism, sphingolipid, and ether lipid metabolism). However, the remaining miRNAs and mRNAs either showed an opposite trend or only changed by a particular shape. Nanorods could specifically alter the changes of PI3K/Akt, AMPK and TNF pathways, cell cycle, and cellular senescence, while nanoflakes caused the changes of Toll and lmd signaling pathways. Conclusions Combined with previous research results, we further revealed the potential biomolecular mechanisms leading to the stronger toxicity of nanorods than that of nanoflakes, and multi-omics is a powerful approach to elucidate morphology-related mode of actions.

Stability and ocular biodistribution of topically administered PLGA nanoparticles

Polymeric nanoparticles have been investigated as potential delivery systems for therapeutic compounds to address many ailments including eye disease. The stability and spatiotemporal distribution of polymeric nanoparticles in the eye are important regarding the practical applicability and efficacy of the delivery system in treating eye disease. We selected poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with lutein, a carotenoid antioxidant associated with eye health, as our model ophthalmic nanodelivery system and evaluated its stability when suspended in various conditions involving temperature and light exposure. We also assessed the ocular biodistribution of the fluorescently labeled nanoparticle vehicle when administered topically. Lutein-loaded nanoparticles were stable in suspension when stored at 4 °C with only 26% lutein release and no significant lutein decay or changes in nanoparticle morphology. When stored at 25 °C and 37 °C, these NPs showed signs of bulk degradation, had significant lutein decay compared to 4 °C, and released over 40% lutein after 5 weeks in suspension. Lutein-loaded nanoparticles were also more resistant to photodegradation compared to free lutein when exposed to ultraviolet (UV) light, decaying approximately 5 times slower. When applied topically in vivo, Cy5-labled nanoparticles showed high uptake in exterior eye tissues including the cornea, episcleral tissue, and sclera. The choroid was the only inner eye tissue that was significantly higher than the control group. Decreased fluorescence in all exterior eye tissues and the choroid at 1 h compared to 30 min indicated rapid elimination of nanoparticles from the eye.

Morphogenesis of Magnetite Mesocrystals: Interplay Between Nanoparticle Morphology and Solvation Shell

In this study, faceted mesocrystals have been assembled from the dispersion of truncated cubic-shaped iron oxide nanoparticles stabilized by oleic acid (OA) molecules using the non-solvent “gas phase diffusion technique” into an organic solvent. The effects of synthesis conditions as well as of the nanoparticle size and shape on the structure and morphogenesis of mesocrystals were examined. The interactions of OA capped iron oxide nanoparticles with solvent molecules were probed by analytical ultracentrifugation and double difference pair distribution function analysis. It was shown that the structure of the organic shell significantly depends on the nature and polarity of solvent molecules.

Morphogenesis of Magnetite Mesocrystals: Interplay Between Nanoparticle Morphology and Solvation Shell

In this study, faceted mesocrystals have been assembled from the dispersion of truncated cubic-shaped iron oxide nanoparticles stabilized by oleic acid (OA) molecules using the non-solvent “gas phase diffusion technique” into an organic solvent. The effects of synthesis conditions as well as of the nanoparticle size and shape on the structure and morphogenesis of mesocrystals were examined. The interactions of OA capped iron oxide nanoparticles with solvent molecules were probed by analytical ultracentrifugation and double difference pair distribution function analysis. It was shown that the structure of the organic shell significantly depends on the nature and polarity of solvent molecules.

Synthesis of silver nanoparticles on a solid surface using a classical photographic method

A classical photographic method, the Becquerel method, produces a positive image comprised of silver nanoparticles on a silver surface. The particles are grown by exposing an iodised silver plate to light in the blue or ultraviolet, which initiates the formation of particles, followed by development (growth) with light in the red portion of the spectrum. Because the Becquerel method is essentially a means of producing a surface of patterned nanoparticles, it also has potential technological applications. This thesis is a systematic investigation of the Becquerel method. . It was determined that the initiation of nanoparticles is effective for wavelengths in the range 447 to 254 nm. The sudden rise in nanoparticle production around 447 nm implicates direct excitation of the AgI layer in the initiation step; however, the behaviour of the action spectrum at shorter wavelengths implies an electron-mediated mechanism. It is possible that both direct excitation and electron-mediated processes occur in the ultraviolet. Scanning electron micrographs indicate that nanoparticle morphology may be dependent on the initiation wavelength, with longer wavelengths producing a variety of shapes, while shorter wavelengths produce primarily dots. Nanoparticle growth (development) was achieved with all wavelengths studied; however, shorter wavelengths photons were more effective than longer wavelengths. The results from a study of the aging of the AgI film suggested that there is period of one or two days during which the film ‘matures,’ becoming more effective for nanoparticle production.

Synthesis of silver nanoparticles on a solid surface using a classical photographic method

A classical photographic method, the Becquerel method, produces a positive image comprised of silver nanoparticles on a silver surface. The particles are grown by exposing an iodised silver plate to light in the blue or ultraviolet, which initiates the formation of particles, followed by development (growth) with light in the red portion of the spectrum. Because the Becquerel method is essentially a means of producing a surface of patterned nanoparticles, it also has potential technological applications. This thesis is a systematic investigation of the Becquerel method. . It was determined that the initiation of nanoparticles is effective for wavelengths in the range 447 to 254 nm. The sudden rise in nanoparticle production around 447 nm implicates direct excitation of the AgI layer in the initiation step; however, the behaviour of the action spectrum at shorter wavelengths implies an electron-mediated mechanism. It is possible that both direct excitation and electron-mediated processes occur in the ultraviolet. Scanning electron micrographs indicate that nanoparticle morphology may be dependent on the initiation wavelength, with longer wavelengths producing a variety of shapes, while shorter wavelengths produce primarily dots. Nanoparticle growth (development) was achieved with all wavelengths studied; however, shorter wavelengths photons were more effective than longer wavelengths. The results from a study of the aging of the AgI film suggested that there is period of one or two days during which the film ‘matures,’ becoming more effective for nanoparticle production.