| 1. |
- Rotundi, Alessandra, et al.
(författare)
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Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the Sun
- 2015
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 347:6220
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Tidskriftsartikel (refereegranskat)abstract
- Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency's Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10(-10) to 10(-7) kilograms, and 48 grains of mass 10(-5) to 10(-2) kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 +/- 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.
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| 2. |
- Sierks, Holger, et al.
(författare)
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On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko
- 2015
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 347:6220
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Tidskriftsartikel (refereegranskat)abstract
- Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
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| 3. |
- Andersson, Alexandra, et al.
(författare)
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Single-vesicle intensity and colocalization fluorescence microscopy to study lipid vesicle fusion, fission, and lipid exchange
- 2022
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Ingår i: Frontiers in Molecular Neuroscience. - : Frontiers Media SA. - 1662-5099. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Interactions of lipid vesicles play important roles in a large variety of functions and dysfunctions in the human body. Vital for several biochemical functions is the interaction between monomeric proteins and lipid membranes, and the induced phenomena such as fusion between vesicles and cell membranes, lipid exchange between the membranes, or vesicle fission. Identification of single events and their frequency of occurrence would provide valuable information about protein-lipid interactions in both healthy and degenerative pathways. In this work, we present a single-vesicle intensity and colocalization fluorescence microscopy assay with a custom-written MATLAB analysis program. The assay can be used to study lipid exchange as well as vesicle fusion and fission between two vesicle populations labeled with different fluorescent dyes. Vesicles from the two populations are first mixed and docked to a glass surface. The sample is then simultaneously imaged using two separate wavelength channels monitoring intensity changes and colocalization of vesicles from the two populations. The monomeric pre-synaptic protein α-synuclein (α-syn) and small unilamellar vesicles consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dioleoyl-sn-glycero-3-phospho-L-serine, (DOPS), and monosialotetrahexosylganglioside (GM1) were used as a model system to evaluate the method. From our analysis, neither α-syn induced fusion nor lipid exchange was observed for vesicles consisting of DOPC:DOPS (7:3). However, including 10% GM1 in the vesicles resulted in a 91% increase of the number of vesicles within 10 min, combined with a 57% decrease in the average fluorescence intensity per vesicle, indicating that approximately half of the vesicles underwent fission. The method facilitates the study of lipid vesicle fusion, fission, and lipid exchange under controlled conditions. It also allows these events to be studied for systems with more complex composition including exosomes and lipid-based drug carriers, to enable a better understanding of their physicochemical properties.
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| 4. |
- Andersson, Alexandra, et al.
(författare)
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The density of anionic lipids modulates the adsorption of α-Synuclein onto lipid membranes
- 2024
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Ingår i: Biophysical Chemistry. - 0301-4622. ; 305
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Tidskriftsartikel (refereegranskat)abstract
- α-Synuclein is an intrinsically disordered presynaptic protein associated with Parkinson's disease. The physiological role of α-Synuclein is not fully understood, but the protein is known to interact with lipid membranes. We here study how membrane charge affects the adsorption of α-Synuclein to (i) supported lipid bilayers and (ii) small unilamellar vesicles with varying amounts of anionic lipids. The results showed that α-Synuclein adsorbs onto membranes containing ≥5% anionic phosphatidylserine (DOPS) lipids, but not to membranes containing ≤1% DOPS. The density of adsorbed α-Synuclein increased steadily with the DOPS content up to 20% DOPS, after which it leveled off. The vesicles were saturated with α-Synuclein at a 3–5 times higher protein density compared to the supported bilayers, which suggests that a more deformable membrane binds more α-Synuclein. Altogether, the results show that both membrane charge density and flexibility influence the association of α-Synuclein to lipid membranes.
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| 5. |
- Bazylińska, Urszula, et al.
(författare)
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Hybrid Theranostic Cubosomes for Efficient NIR-Induced Photodynamic Therapy
- 2022
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 16:4, s. 5427-5438
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, lipid bicontinuous cubic liquid-crystalline nanoparticles known as cubosomes have been under investigation because of their favorable properties as drug nanocarriers useful for anticancer treatments. Herein, we present organic/inorganic hybrid, theranostic cubosomes stabilized in water with a shell of alternate layers of chitosan, single strand DNA (model genetic material for potential gene therapy), and folic acid-chitosan conjugate (the outmost layer), coencapsulating up-converting Er3+ and Yb3+ codoped NaYF4 nanoparticles and daunorubicin. The latter acts as a chemotherapeutic drug of photosensitizing activity, while up-converting nanoparticles serve as energy harvester and diagnostic agent. Cellular uptake and NIR-induced photodynamic therapy were evaluated in vitro against human skin melanoma (MeWo) and ovarian (SKOV-3) cancer cells. Results evidenced the preferential uptake of the theranostic cubosomes in SKOV-3 cells in comparison to uptake in MeWo cells, and this effect was enhanced by the folic acid functionalization of the cubosomes surface. Nanocarriers coloaded with the hybrid fluorophores exhibited a superior NIR-induced photodynamic activity, also confirmed by the improved mitochondrial activity and the most affecting f-actin fibers of cytoskeleton. Similar results, but with higher photocytotoxicity, were detected when folic acid-functionalized cubosomes were incubated with SKOV-3 cells. Taken on the whole, these results prove these hybrid cubosomes are good candidates for the photodynamic treatment of tumor lesions.
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| 6. |
- Casula, Luca, et al.
(författare)
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Polyphosphoester-stabilized cubosomes encapsulating a Ru(II) complex for the photodynamic treatment of lung adenocarcinoma
- 2024
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797. ; 670, s. 234-245
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Tidskriftsartikel (refereegranskat)abstract
- The clinical translation of photosensitizers based on ruthenium(II) polypyridyl complexes (RPCs) in photodynamic therapy of cancer faces several challenges. To address these limitations, we conducted an investigation to assess the potential of a cubosome formulation stabilized in water against coalescence utilizing a polyphosphoester analog of Pluronic F127 as a stabilizer and loaded with newly synthesized RPC-based photosensitizer [Ru(dppn)2(bpy-morph)](PF6)2 (bpy-morph = 2,2′-bipyridine-4,4′-diylbis(morpholinomethanone)), PS-Ru. The photophysical characterization of PS-Ru revealed its robust capacity to induce the formation of singlet oxygen (1O2). Furthermore, the physicochemical analysis of the PS-Ru-loaded cubosomes dispersion demonstrated that the encapsulation of the photosensitizer within the nanoparticles did not disrupt the three-dimensional arrangement of the lipid bilayer. The biological tests showed that PS-Ru-loaded cubosomes exhibited significant phototoxic activity when exposed to the light source, in stark contrast to empty cubosomes and to the same formulation without irradiation. This promising outcome suggests the potential of the formulation in overcoming the drawbacks associated with the clinical use of RPCs in photodynamic therapy for anticancer treatments.
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| 7. |
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| 8. |
- Fornasier, Marco, et al.
(författare)
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Lipid vesicular gels for topical administration of antioxidants
- 2022
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 0927-7765. ; 213
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Tidskriftsartikel (refereegranskat)abstract
- The application of a formulation on the skin represents an effective way to deliver bio-active molecules for therapeutical purposes. Moreover, the outermost skin layer, the stratum corneum, can be overcome by employing chemical permeation enhancers and edge activators as components. Several lipids can be considered as permeation enhancers, such as the ubiquitous monoolein, one of the most used building blocks for the preparation of lipid liquid crystalline nanoparticles which are applied as drug carriers for nanomedicine applications. Recent papers highlighted how bile salts can affect the phase behavior of monoolein to obtain drug carriers suitable for topical administration, given their role as edge activators into the formulation. Herein, the encapsulation of natural antioxidants (caffeic acid and ferulic acid) into lipid vesicular gels (LVGs) made by monoolein and sodium taurocholate (TC) in water was studied to produce formulations suitable for topical application. TC induces a bicontinuous cubic to multilamellar phase transition for monoolein in water at the given concentrations, and by increasing its content into the formulations, unilamellar LVGs are formed. The encapsulation of the two antioxidants did not affect significantly the structure of the gels. The oscillating rheological studies showed that ferulic acid has a structuring effect on the lipid matrix, in comparison with the empty dispersion and the one containing caffeic acid. These gels were then tested in vitro on new-born pig skin to evaluate their efficacy as drug carriers for topical administration, showing that caffeic acid is mostly retained in the gel whereas ferulic acid is released at a higher degree. The data herein reported provide some further information on the effect of bile salts on the lipid self-assembly to evaluate useful compositions for topical administration of natural antioxidants.
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| 9. |
- Fornasier, Marco, et al.
(författare)
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Surface-modified nanoerythrosomes for potential optical imaging diagnostics
- 2021
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 582:Part A, s. 246-253
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Tidskriftsartikel (refereegranskat)abstract
- Nanoerythrosomes (NERs), vesicle-like nanoparticles derived from red blood cells, represent a new and interesting vector for therapeutic molecules and imaging probes, mainly thanks to their high stability and excellent biocompatibility. Aiming to present a proof-of-concept of the use of NERs as diagnostic tools for in vitro/in vivo imaging purposes, we report here several functionalization routes to decorate the surfaces of NERs derived from bovine blood with two different fluorophores: 7-amino-4-methylcumarin and dibenzocyclooctinecyanine5.5. Notably, the fluorophores were cross-linked to the NERs surface with glutaraldehyde and, in the case of dibenzocyclooctinecyanine5.5, also using a click-chemistry route, termed strain-promoted azide-alkyne cycloaddition. The physicochemical characterization highlighted the high stability of the NERs derivatives in physiological conditions. Furthermore, the loading efficiency of the fluorophores on the NERs surface was evaluated using both UV–Vis spectroscopy and fluorescence microscopy.
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| 10. |
- Fornasier, Marco, et al.
(författare)
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Tuning lipid structure by bile salts: Hexosomes for topical administration of catechin
- 2021
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 1873-4367 .- 0927-7765. ; 199
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Tidskriftsartikel (refereegranskat)abstract
- The delivery of bio-active molecules through the skin is challenging given the complex structure of its outer layer, the stratum corneum. Here we explore the possibility to encapsulate natural compounds into nanocarriers containing permeation enhancers that can affect the fluidity of the stratum corneum lipids. This approach is expected to facilitate dermal or transdermal release. For this purpose, the application of bile salts, which are natural surfactants involved in vivo in lipid digestion, was exploited.Bile salts were added to lipid liquid crystalline nanoparticles (NPs) made of monoolein for antioxidant topical delivery. Monoolein self-assembly behaviour in water was affected by the presence of bile salts molecules, giving a transition from a bicontinuous cubic to unilamellar vesicles dispersion. By adding oleic acid (OA), the change of curvature in the system led to a reverse hexagonal phase. The morphology, structure and size of the nanocarriers was investigated before the nanoparticles were loaded with catechin, a natural antioxidant occurring in plants and food. The encapsulation did not affect significantly the formulation phase behaviour. The formulation loaded with bile salts and catechin was thereafter tested in vitro on the skin from new-born pig. The results for two different lipid formulations without bile salts were compared under the same experimental conditions and with the same antioxidant. The formulation with bile salts showed the best performance, allowing a superior permeation of catechin in the different skin layers in comparison with formulations without bile salt.
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