Search results for "Caps"
showing 10 items of 745 documents
Mosaic Qβ coats as a new presentation model
1998
The new protein carrier was developed on the basis of recombinant RNA phage Qbeta capsid. C-terminal UGA extension of the short form of Qbeta coat, so-called A1 extension, served as a target for presentation of foreign peptides on the outer surface of mosaic Qbeta particles. In conditions of enhanced UGA suppression, the proportion of A1-extended to short coats in mosaic particles dropped from 48% to 14%, with an increase of the length of A1 extension. A model insertion, short preS1 epitope 31-DPAFR-35 of hepatitis B surface antigen, demonstrated superficial location on the mosaic Qbeta particles and ensured specific antigenicity and immunogenicity.
Increase in stability and change in supramolecular structure of β-carotene through encapsulation into polylactic acid nanoparticles
2011
International audience; β-Carotene (BC) exhibits controversial antioxidant properties as it may act also as a prooxidant. Its stability toward oxidation depends on its dispersion form and can be increased through encapsulation. In this study, oxidation of BC from synthetic and natural origins was investigated after dispersion in Tween micelles or poly lactic acid (PLA) particles. Two oxidation systems were used: autooxidation and oxidation by xanthine oxidase-generated-reactive oxygen species. Results showed that synthetic BC formed nanometric negatively-charged particles in both Tween micelle and PLA systems, whereas the natural BC sample used was shown to be already pre-oxidised, forming …
Stability of carotenoid extracts of gấc (Momordica cochinchinensis) towards cooxidation — Protective effect of lycopene on β-carotene
2011
International audience; Momordica cochinchinensis, so-called gấc in Vietnam, is considered as a fruit with high nutritional potential. Its antioxidant property, due to a high concentration of carotenes (β-carotene and lycopene), is particularly estimated. In this study, we have investigated the degradation of carotene extracts obtained from gấc aril. These extracts were dispersed in the aqueous phase in Tween 80 micelles or were encapsulated into polylactic acid (PLA) particles. In both cases, carotenes were far less degraded than synthetic β-carotene. However, the degradation of lycopene was still rapid (around 1 mM lycopene degraded per hour), whereas β-carotene was almost not bleached. M…
Impact of molecular weight on the formation of electrosprayed chitosan microcapsules as delivery vehicles for bioactive compounds.
2016
The molecular weight of chitosan is one of its most determinant characteristics, which affects its processability and its performance as a biomaterial. However, information about the effect of this parameter on the formation of electrosprayed chitosan microcapsules is scarce. In this work, the impact of chitosan molecular weight on its electrosprayability was studied and correlated with its effect on the viscosity, surface tension and electrical conductivity of solutions. A Discriminant Function Analysis revealed that the morphology of the electrosprayed chitosan materials could be correctly predicted using these three parameters for almost 85% of the samples. The suitability of using elect…
Stability and bioaccessibility of EGCG within edible micro-hydrogels. Chitosan vs. gelatin, a comparative study
2016
Micro-hydrogels are very promising systems for the protection and controlled delivery of sensitive bioactives, but limited knowledge exists regarding the impact of this encapsulation on their bioaccessibility. In this work, two different hydrogel-forming biopolymers (gelatin and chitosan) were compared as wall materials for the microencapsulation of a model flavonoid, (−)-epigallocatechin gallate (EGCG). Results showed that gelatin was more adequate as wall material for the encapsulation of EGCG than chitosan, achieving higher encapsulation efficiencies (95% ± 6%), being more effective in delaying EGCG release and degradation in aqueous solution and exhibiting a 7 times higher bioaccessibil…
Controlling protein interactions in blood for effective liver immunosuppressive therapy by silica nanocapsules
2020
Immunosuppression with glucocorticoids is a common treatment for autoimmune liver diseases and after liver transplant, which is however associated with severe side-effects. Targeted delivery of glucocorticoids to inflammatory cells, e.g. liver macrophages and Kupffer cells, is a promising approach for minimizing side effects. Herein, we prepare core–shell silica nanocapsules (SiO2 NCs) via a sol–gel process confined in nanodroplets for targeted delivery of dexamethasone (DXM) for liver immunosuppressive therapy. DXM with concentrations up to 100 mg mL−1 in olive oil are encapsulated while encapsulation efficiency remains over 95% after 15 days. Internalization of NCs by non-parenchymal muri…
Noroviral P-Particles as an In Vitro Model to Assess the Interactions of Noroviruses with Probiotics
2014
Noroviruses (NoVs) are the main etiologic agents of acute epidemic gastroenteritis and probiotic bacteria have been reported to exert a positive effect on viral diarrhea. The protruding (P) domain from NoVs VP1 capsid protein has the ability to assemble into the so-called P-particles, which retain the binding ability to host receptors. We purified the P-domains from NoVs genotypes GI.1 and GII.4 as 6X(His)-tagged proteins and determined that, similar to native domains, they were structured into P-particles that were functional in the recognition of the specific glycoconjugated receptors, as established by surface plasmon resonance experiments. We showed that several lactic acid bacteria (pr…
Special Uses of Viscoelastics
2000
The possibilities of viscoelastic use in phacoemulsification will be outlined in the following figures. Many ophthalmic surgeons apply viscoelastic substances in capsulorhexis to achieve a deep anterior chamber and extend the pupillary space (with a small pupil). Care must be taken during injection so that aqueous is permitted to flow out. When using a paracentesis to inject viscoelastic (Fig. 59), it must be big enough to allow aqueous outflow. For complete aqueous exchange in the anterior chamber, it is advisable to inject the viscoelastic into the opposite chamber angle.
Multiarm star polyglycerol-block-poly(HEMA) as a versatile precursor for the preparation of micellar nanocapsules with different properties
2007
Well-defined multiarm star polymer with hyperbranched polyglycerol as core and poly(2-hydroxyethyl methacrylate) (PHEMA) as arms were used as precursor for the preparation of inverted and aqueous micellar nanocapsules. The partial modification of the hydroxyl groups of PHEMA arms with aliphatic chains led to the formation of inverted micellar nanocapsules. The hydrophilic dye encapsulation capacity of the inverted micelles can be enhanced significantly by transforming the inner hydroxyl groups of PHEMA arms into quaternized amine groups. The modification of the outer and inner hydroxyl groups of PHEMA arms with polyethylene glycol acid chloride and pivaloyl chloride, respectively, resulted …
Arginine-rich peptides are blockers of VR-1 channels with analgesic activity
2000
Vanilloid receptors (VRs) play a fundamental role in the transduction of peripheral tissue injury and/or inflammation responses. Molecules that antagonize VR channel activity may act as selective and potent analgesics. We report that synthetic arginine-rich hexapeptides block heterologously expressed VR-1 channels with submicromolar efficacy in a weak voltage-dependent manner, consistent with a binding site located near/at the entryway of the aqueous pore. Dynorphins, natural arginine-rich peptides, also blocked VR-1 activity with micromolar affinity. Notably, synthetic and natural arginine-rich peptides attenuated the ocular irritation produced by topical capsaicin application onto the eye…