| 1. |
- Amin, Muhammad Umair, et al.
(författare)
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Ultrasound-Responsive Smart Drug Delivery System of Lipid Coated Mesoporous Silica Nanoparticles
- 2021
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Ingår i: Pharmaceutics. - : MDPI. - 1999-4923. ; 13:9
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Tidskriftsartikel (refereegranskat)abstract
- The immediate release of chemotherapeutics at the target site, along with no premature release in circulation is always challenging. The purpose of this study was to develop a stimuli responsive drug delivery system, composed of lipid supported mesoporous silica nanoparticles (MSNPs) for triggered drug release at the target site and simultaneously avoiding the premature release. MSNPs with a higher drug loading capacity and very slow release were designed so as to enhance release by FDA approved US-irradiation. Doxorubicin, as a model drug, and perfluoropentane (PFP) as a US responsive material, were entrapped in the porous structure of MSNPs. Lipid coating enhanced the cellular uptake and in addition provided a gatekeeping effect at the pore opening to reduce premature release. The mechanical and thermal effects of US induced the conversion of liquid PFP to a gaseous form that was able to rupture the lipid layer, resulting in triggered drug release. The prolonged stability profile and non-toxic behavior made them suitable candidate for the delivery of anticancer drugs. This smart system, with the abilities of better cellular uptake and higher cytotoxic effects on US-irradiation, would be a good addition to the applied side of chemotherapeutic advanced drug delivery systems.
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| 2. |
- Ma, Wei, et al.
(författare)
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The distribution of alpha-kleisin during meiosis in the holocentromeric plant Luzula elegans
- 2016
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Ingår i: Chromosome Research. - : SPRINGER. - 0967-3849 .- 1573-6849. ; 24:3, s. 393-405
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Tidskriftsartikel (refereegranskat)abstract
- Holocentric chromosomes occur in a number of independent eukaryotic lineages, and they form holokinetic kinetochores along the entire poleward chromatid surfaces. Due to this alternative chromosome structure, Luzula elegans sister chromatids segregate already in anaphase I followed by the segregation of the homologues in anaphase II. However, not yet known is the localization and dynamics of cohesin and the structure of the synaptonemal complex (SC) during meiosis. We show here that the alpha-kleisin subunit of cohesin localizes at the centromeres of both mitotic and meiotic metaphase chromosomes and that it, thus, may contribute to assemble the centromere in L. elegans. This localization and the formation of a tripartite SC structure indicate that the prophase I behaviour of L. elegans is similar as in monocentric species.
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| 3. |
- Meister, Anette, et al.
(författare)
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Formation of square lamellae by self-assembly of long-chain bolaphospholipids in water
- 2010
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 6:6, s. 1317-1324
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Tidskriftsartikel (refereegranskat)abstract
- The self-assembly process of the symmetric single-chain polymethylene-1,omega-bis(phosphocholine) (PC-C34-PC) with a chain length of 34 carbon atoms and two polar phosphocholine headgroups when put into water is exclusively driven by hydrophobic interactions of the long alkyl chains. This process leads to the formation of a dense network of helical nanofibers and the formation of a hydrogel (Meister et al. J. Phys. Chem. B, 2008, 112, 4506). In contrast, the single-chain bolalipids tetra-and hexatriacontane-1,omega-diyl-bis[2-(dimethylammonio)ethylphosphate] (Me2PE-Cn-Me2PE, n = 34, 36) and the partly deuterated analogue Me2PE-C11-(CD2)12-C11-Me2PE (dMe(2)PE-C34-Me2PE) form a different type of stable aggregate. In a first step, the self-assembly of these long-chain bolalipids in water at room temperature leads to the formation of a dense network of nanofibers which eventually form a hydrogel. Within one day, the nanofibers transform into square lamellae that grow up to an edge length of about 100 nm. Nanofibers are linked to one or two (opposite) corners of the squares leading to the appearance of a kite-like structure. After one week, all fibers have been transformed into square lamellae which are apparently stacked and form a gel cake. Within several weeks, a more compact cake is formed by syneresis, i.e. the expulsion of water.
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| 4. |
- Meister, Anette, et al.
(författare)
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Mixing behaviour of a symmetrical single-chain bolaamphiphile with phospholipids
- 2007
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 3:8, s. 1025-1031
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Tidskriftsartikel (refereegranskat)abstract
- The mixing behavior of the sym. long-chain bolaamphiphile dotriacontane-1,1'-diyl-bis-[2-(trimethylammonio)ethylphosphate] (PC-C32-PC) with conventional phospholipids (DPPC, DMPC, and POPC) was investigated by differential scanning calorimetry and transmission electron microscopy. PC-C32-PC by itself forms nanofibers at room temp., which convert to micellar aggregates at higher temps. The length of the bolaamphiphile corresponds roughly to the thickness of a lipid bilayer. However, a significant insertion of the bolaamphiphile into the phospholipid bilayer vesicles was not obsd. in any of the mixed systems. This is apparently due to packing problems caused by the larger space requirement of the phosphocholine headgroups of PC-C32-PC compared to the small cross-sectional area of the alkyl chain. Obviously, the insertion of these bolaamphiphiles into membrane structures with parallel oriented mols. leads to large void vols. because of this packing problem, so that the bolaamphiphiles prefer to self-assemble into fibers, where the chains can get in closer contact. On the other hand, up to a certain molar ratio, double-chain phospholipids can easily be inserted into the hydrophobic pockets of the bolaamphiphile fibers, where they stabilize the fiber structure.
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