•Active PVA films with seaweed-based CNC and basil leaf extract were prepared.•Films showed reduced transparency, and improved WVP and tensile properties.•Films showed good antimicrobial and ...antioxidant activity.•PVA film added with CNC and BE can be used as active packaging material for food.
Polyvinyl alcohol (PVA) films containing seaweed extracted cellulose nanocrystal (CNC) (5% w/v) and 5, 10, and 20% (w/v) basil leaves extract (BE) were prepared using the solvent casting method, and their physical properties, and antimicrobial and antioxidant activity were analyzed. The addition of 5% (w/v) CNC to PVA improved the tensile strength and water vapor permeability. Addition of BE to film the antioxidant activity and antimicrobial properties of the films were enhanced. Further, increasing the amount of BE slightly affected the color of the bio-nanocomposites. The thermal stability of films was improved with addition of CNC. Due to functional groups and linkage properties of the CNC surface and macromolecular chains of the PVA were responsible for improvement of the interfacial interactions between the CNC and PVA. The dispersion of CNC in PVA were affected with increase in the amount of BE in PVA. This study showed the benefits of the incorporation of CNC and BE into PVA films and the potential for their use as active packaging material for food.
Development of protein cages for encapsulation of active enzyme cargoes and their subsequent arrangement into a controllable three-dimensional array is highly desirable. However, cargo capture is ...typically challenging because of difficulties in achieving reversible assembly/disassembly of protein cages in mild conditions. Herein we show that by using an unusual ferritin cage protein that undergoes triggerable assembly under mild conditions, we can achieve reversible filling with protein cargoes including an active enzyme. We demonstrate that these filled cages can be arrayed in three-dimensional crystal lattices and have an additional chaperone-like effect, increasing both thermostability and enzymatic activity of the encapsulated enzyme.
Imprints of potato sprout (
Solanum tuberosum
L.), gingko leaves
(Gingko biloba
L.
)
and strawberries
(Fragaria x ananassa
Duch.
)
were successfully imaged by desorption electrospray ionization mass ...spectrometry (DESI-MS) on TLC plates through blotting assisted by heating and/or solvent extraction. Ion images showing the distribution of significant compounds such as glycoalkaloid toxins in potato sprout, ginkgolic acids and flavonoids in ginkgo leaves, and sugars and anthocyanidin in strawberry were obtained. Practical implications of this work include analysis of a wide range of irregular or soft materials by different imprinting conditions without requiring the addition of matrices or use of specific kinds of surfaces.
Figure
DESI-MS Imaging analysis of gingko leaves imprinted onto TLC plates. The ion image shows the spatial distribution of quinic acid ion (m/z 191).
A simple, high yield, chemical process is developed to fabricate layered h-BN nanosheets and BCNO nanoparticles with a diameter of ca. 5 nm at 700 °C. The use of the eutectic LiCl/KCl salt melt ...medium enhances the kinetics of the reaction between sodium borohydride and urea or guanidine as well as the dispersion of the nanoparticles in water. The carbon content can be tuned from 0 to 50 mol % by adjusting the reactant ratio, thus providing precise control of the light emission of the particles in the range 440–528 nm while reaching a quantum yield of 26%. Because of their green synthesis, low toxicity, small size, and stability against aggregation in water, the as-obtained photoluminescent BCNO nanoparticles show promise for diagnostics and optoelectronics.
Chemistry of the Retinoid (Visual) Cycle Kiser, Philip D; Golczak, Marcin; Palczewski, Krzysztof
Chemical reviews,
01/2014, Letnik:
114, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The biochemical processes involved in the retinoid vision cycle were investigated. Retinoids are shown to support vision through light-sensitive rod and cone photoreceptor cells in the retina, and ...data support the contention that human retinal diseases are connected to alterations in the retinoid cycle.
In this study, pea protein isolate (PPI) nanoparticles were fabricated with calcium-induced cross-linking and the potential as a nano-carrier for protecting resveratrol (RES) from degradation as well ...as improving its antioxidant activities was investigated. Ca2+ ions concentration and pH value had significant impacts on the formation of PPI nanoparticles. Dissociation assays suggested that PPI nanoparticles were mainly formed and stabilized by Ca2+ ions induced salt-bridge, hydrophobic interaction, and hydrogen bonding. Encapsulation efficiency (EE) and Loading amount (LA) of RES in PPI nanoparticles was 74.08%, and 30.24 μg/mg protein, respectively. Fluorescence emission results suggested that the formation of RES-PPI nanoparticles was primarily driven with hydrophobic interaction. AFM results clearly indicated that both RES-PPI nanocomplexes and RES-PPI nanoparticles were nano-scale, spherical shaped and distributed uniformly. RES-PPI nanoparticles exhibited higher physicochemical stability (Z-average diameter stability and RES retention) than RES-SPI nanocomplexes. Antioxidant ability of RES can be remarkably enhanced with both PPI-based nano-delivery systems. Ca2+ ions induced PPI nanoparticles obtained in this study have the great potential as functional delivery systems for hydrophobic nutraceuticals in food, and pharmaceutical industry.
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•PPI nanoparticle was fabricated with calcium-induced cross-linking.•RES-PPI nanoparticles were primarily driven with hydrophobic interaction.•RES retention in PPI nanoparticle is higher than that in PPI nanocomplex.•Antioxidant ability of RES can be enhanced with PPI-based nano-delivery system.
Multiple-shelled Fe2O3 yolk-shell particles were synthesized using the spray drying method and intended as a suitable support for the immobilization of commercial enzymes such as glucose oxidase ...(GOx), horseradish peroxidase (HRP), and laccase as model enzymes. Yolk-shell particles have an average diameter of 1-3 μm with pore diameters in the range of 16 to 28 nm. The maximum immobilization of GOx, HRP, and laccase resulted in the enzyme loading of 292, 307 and 398 mg per g of support, respectively. After cross-linking of immobilized laccase by glutaraldehyde, immobilization efficiency was improved from 83.5% to 90.2%. K(m) and V(max) values were 41.5 μM and 1722 μmol min(-1) per mg protein for cross-linked laccase and those for free laccase were 29.3 μM and 1890 μmol min(-1) per mg protein, respectively. The thermal stability of the enzyme was enhanced up to 18-fold upon cross-linking, and the enzyme retained 93.1% of residual activity after ten cycles of reuse. The immobilized enzyme has shown up to 32-fold higher stability than the free enzyme towards different solvents and it showed higher efficiency than free laccase in the decolorization of dyes and degradation of bisphenol A. The synthesized yolk-shell particles have 3-fold higher enzyme loading efficiency and lower acute toxicity than the commercial Fe2O3 spherical particles. Therefore, the use of unique yolk-shell structure Fe2O3 particles with multiple-shells will be promising for the immobilization of various enzymes in biotechnological applications with improved electrochemical properties. To the best of our knowledge, this is the first report on the use of one pot synthesized Fe2O3 yolk-shell structure particles for the immobilization of enzymes.
Toward preparing strong multi-biofunctional materials, poly(ethylenimine) (PEI) conjugated graphene oxide (GO_PEI) was synthesized using poly(acrylic acid) (PAA) as a spacer and incorporated in ...poly(ε-caprolactone) (PCL) at different fractions. GO_PEI significantly promoted the proliferation and formation of focal adhesions in human mesenchymal stem cells (hMSCs) on PCL. GO_PEI was highly potent in inducing stem cell osteogenesis leading to near doubling of alkaline phosphatase expression and mineralization over neat PCL with 5% filler content and was ≈50% better than GO. Remarkably, 5% GO_PEI was as potent as soluble osteoinductive factors. Increased adsorption of osteogenic factors due to the amine and oxygen containing functional groups on GO_PEI augment stem cell differentiation. GO_PEI was also highly efficient in imparting bactericidal activity with 85% reduction in counts of E. coli colonies compared to neat PCL at 5% filler content and was more than twice as efficient as GO. This may be attributed to the synergistic effect of the sharp edges of the particles along with the presence of the different chemical moieties. Thus, GO_PEI based polymer composites can be utilized to prepare bioactive resorbable biomaterials as an alternative to using labile biomolecules for fabricating orthopedic devices for fracture fixation and tissue engineering.
•Structure at different scales of Ca(II)-alginate beads were assessed by SAXS.•Gums as second excipients induce a stabilization in the microstructure at rod scale.•Gums stabilize the size and density ...of the dimers and the interconnection of rods.•Guar gum improves the lactase activity during operation conditions.
Previous works show that the addition of trehalose and gums in β-galactosidase (lactase) Ca(II)-alginate encapsulation systems improved its intrinsic stability against freezing and dehydration processes in the pristine state. However, there is no available information on the evolution in microstructure due to the constraints imposed by the operational conditions. The aim of this research is to study the time course of microstructural changes of Ca(II)-alginate matrices driven by the presence of trehalose, arabic and guar gums as excipients and to discuss how these changes influence the diffusional transport (assessed by LF-NMR) and the enzymatic activity of the encapsulated lactase.
The structural modifications at different scales were assessed by SAXS. The incorporation of gums as second excipients induces a significant stabilization in the microstructure not only at the rod scale, but also in the characteristic size and density of alginate dimers (basic units of construction of rods) and the degree of interconnection of rods at a larger scale, improving the performance in terms of lactase activity.
Man-made glues often fail to stick in wet environments because of hydration-induced softening and dissolution. The wound healing process of a tunicate inspired the synthesis of gallol-functionalized ...copolymers as underwater adhesive. Copolymers bearing three types of phenolic groups, namely, phenol, catechol, and gallol, were synthesized via the methoxymethyl protection/deprotection route. Surprisingly, the newly synthesized copolymers bearing gallol groups exhibited stronger adhesive performances (typically 7× stronger in water) than the widely used catechol-functionalized copolymers under all tested conditions (in air, water, seawater, or phosphate-buffered saline solution). The higher binding strength was ascribed to the tridentate-related interfacial interaction and chemical cross-linking. Moreover, gallol-functionalized copolymers adhered to all tested surfaces including plastic, glass, metal, and biological material. In seawater, the performance of gallol-functionalized copolymer even exceeds the commercially available isocyanate-based glue. The insights from this study are expected to help in the design of biomimetic materials containing gallol groups that may be utilized as potential bioadhesives and for other applications. The results from such a kind of comparable study among phenol, catechol, and gallol suggests that tridentate structure should be better than bidentate structure for bonding to the surface.
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