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- 2019
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Tidskriftsartikel (refereegranskat)
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- Fornara, Andrea, 1980-, et al.
(författare)
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Polymeric/inorganic multifunctional nanoparticles for simultaneous drug delivery and visualization
- 2010
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Ingår i: Materials Research Society Symposium Proceedings. - 0272-9172 .- 1946-4274. ; 1257
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles consisting of different biocompatible materials are attracting a lot of interest in the biomedical area as useful tools for drug delivery, photo-therapy and contrast enhancement agents in MRI, fluorescence and confocal microscopy. This work mainly focuses on the synthesis of polymeric/inorganic multifunctional nanoparticles (PIMN) based on biocompatible di-block copolymer poly(L,L-lactide-co-ethylene glycol) (PLLA-PEG) via an emulsion-evaporation method. Besides containing a hydrophobic drug (Indomethacin), these polymeric nanoparticles incorporate different visualization agents such as superparamagnetic iron oxide nanoparticles (SPION) and fluorescent Quantum Dots (QDs) that are used as contrast agents for Magnetic Resonance Imaging (MRI) and fluorescence microscopy together. Gold Nanorods are also incorporated in such nanostructures to allow simultaneous visualization and photodynamic therapy. MRI studies are performed with different loading of SPION into PIMN, showing an enhancement in T2 contrast superior to commercial contrast agents. Core-shell QDs absorption and emission spectra are recorded before and after their loading into PIMN. With these polymeric/inorganic multifunctional nanoparticles, both MRI visualization and confocal fluorescence microscopy studies can be performed. Gold nanorods are also synthesized and incorporated into PIMN without changing their longitudinal absorption peak usable for lased excitation and phototherapy. In-vitro cytotoxicity studies have also been performed to confirm the low cytotoxicity of PIMN for further in-vivo studies.
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- Guo, Peng Fei, et al.
(författare)
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Iron-chelated thermoresponsive polymer brushes on bismuth titanate nanosheets for metal affinity separation of phosphoproteins
- 2020
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 0927-7765. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- Separation of phosphoproteins plays an important role for identification of biomarkers in life science. In this work, bismuth titanate supported, iron-chelated thermoresponsive polymer brushes were prepared for selective separation of phosphoproteins. The iron-chelated thermoresponsive polymer brushes were synthesized by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and glycidyl methacrylate, followed by a ring opening reaction of epoxy group, and chelation of the obtained cis-diols with Fe3+ ions. The composite material was characterized to determine the size and thickness, the content of the organic polymer and the metal loading. The bismuth titanate supported, iron-chelated thermoresponsive polymer brushes showed selective binding for phosphoproteins in the presence of abundant interfering proteins, and a high binding capacity for phosphoproteins by virtue of the metal affinity between the metal ions on the polymer brushes and the phosphate groups in the phosphoproteins (664 mg β-Casein per g sorbent). The thermoresponsive property of the polymer brushes made it possible to adjust phosphoprotein binding by changing temperature. Finally, separation of phosphoproteins from a complex biological sample (i.e. milk) was demonstrated using the nanosheet-supported thermoresponsive polymer brushes.
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- Omollo, Wyckliffe Omondi, et al.
(författare)
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Article Spatial heterogeneity of neoand paleo-endemism for plants in Madagascar
- 2024
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Ingår i: CURRENT BIOLOGY. - 0960-9822 .- 1879-0445. ; 34:6
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Tidskriftsartikel (refereegranskat)abstract
- Madagascar is a biogeographically unique island with a remarkably high level of endemism. However, endemic taxa in Madagascar are massively threatened due to unprecedented pressures from anthropogenic habitat modification and climate change. A comprehensive phylogeny-based biodiversity evaluation of the island remains lacking. Here, we identify hotspots of taxonomic and phylogenetic plant diversity and neoand paleo-endemism by generating a novel dated tree of life for the island. The tree is based on unprecedented sampling of 3,950 species (33% of the total known species) and 1,621 genera (93% of the total known genera and 69% of endemic genera) of Malagasy vascular plants. We find that island -endemic genera are concentrated in multiple lineages combining high taxonomic and phylogenetic diversity. Integrating phylogenetic and geographic distribution data, our results reveal that taxon richness and endemism are concentrated in the northern, eastern, and southeastern humid forests. Paleo-endemism centers are concentrated in humid eastern and central regions, whereas neo-endemism centers are concentrated in the dry and spiny forests in western and southern Madagascar. Our statistical analysis of endemic genera in each vegetation region supports a higher proportion of ancient endemic genera in the east but a higher proportion of recent endemic genera in the south and west. Overlaying centers of phylogenetic endemism with protected areas, we identify conservation gaps concentrated in western and southern Madagascar. These gaps should be incorporated into conservation strategies to aid the protection of multiple facets of biodiversity and their benefits to the Malagasy people.
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- Xing, Li-Da, et al.
(författare)
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Asianopodus-type footprints from the Hekou Group of Honggu District, Lanzhou City, Gansu, China and the “heel” of large theropod tracks
- 2014
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Ingår i: Palaeoworld. - : Elsevier BV. - 1871-174X .- 1875-5887. ; 23:3-4, s. 304-313
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Tidskriftsartikel (refereegranskat)abstract
- An increasing number of dinosaur tracksites have been reported from the Cretaceous Hekou Group deposits of the Lanzhou-Minhe Basin in theGansu Province region. These include small sites such as the Huazhuang tracksite, from the Honggu District reported here, the Zhongpu tracksitewith multiple track levels but few well-preserved tracks, other small tracksites currently under investigation, and the large and diverse LiujixiaNational Dinosaur Geopark site at Yanguoxia, where intensive study is ongoing. Collectively these sites reveal that ichnofaunas in the HekouGroup are widespread and diverse. The Huazhuang tracksite yields a small assemblage of moderately well-preserved theropod tracks assigned toAsianopodus. This is the first report of Asianopodus from the Hekou Group. Huazhuang Asianopodus belongs to the Eubrontes morphotype. Thelarge theropod tracks from Lanzhou-Minhe Basin were left by large theropod trackmakers with the same general foot morphology. The specimensare described in detail and compared with other theropod track morphotypes from the Lower Cretaceous of China and elsewhere. In general,although the metatarsophalangeal pads of some Jurassic Eubrontes-type tracks are aligned with the axis of digit III, this feature appears mostcommon in the Early Cretaceous theropod (Eubrontes-type) tracks.
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| 8. |
- Ye, Fei, et al.
(författare)
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Multifunctional core-shell nanoparticles : superparamagnetic, mesoporous, and thermosensitive
- 2011
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Ingår i: Journal of nanoparticle research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 13:11, s. 6157-6167
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional core-shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into one entity, which is composed of a single Fe3O4 NP as the magnetic core, mesoporous silica (mSiO2) with cavities as the sandwiched layer, and thermosensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) copolymer as the outer shell. The mSiO2-coated Fe3O4 NPs (Fe3O4@mSiO2) are monodisperse and the particle sizes were varied from 25 to 95 nm by precisely controlling the thickness of mSiO2-coating layer. The P(NIPAAm-co-AAm) were then grown onto surface-initiator-modified Fe3O4@mSiO2 NPs through free radical polymerization. These core-shell composite NPs (designated as Fe3O4@mSiO2@P(NIPAAm-co-AAm)) were found to be superparamagnetic with high r2 relaxivity. To manipulate the phase transition behavior of these thermosensitive polymer-coated NPs for future in vivo applications, the characteristic lower critical solution temperature (LCST) was subtly tuned by adjusting the composition of the monomers to be around the human body temperature (i.e. 37 °C), from ca. 34 to ca. 42 °C. The thermal response of the core-shell composite NPs to the external magnetic field was also demonstrated. Owing to their multiple functionality characteristics, these porous superparamagnetic and thermosensitive NPs may prove valuable for simultaneous magnetic resonance imaging (MRI), temperature-controlled drug release, and temperature-programed magnetic targeting and separation applications.
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| 9. |
- Ye, Fei, et al.
(författare)
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Synthesis of high aspect ratio gold nanorods and their effects on human antigen presenting dendritic cells
- 2011
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Ingår i: International Journal Of Nanotechnology. - 1475-7435. ; 8:8-9, s. 631-652
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Tidskriftsartikel (refereegranskat)abstract
- High aspect ratio (AR) gold nanorods (NRs) attract great interest for biomedical applications due to their novel physicochemical properties. Here, we report a facile method for preparation of high AR gold NRs through a seedless surfactant-mediated protocol with the additive of nitric acid. High-resolution transmission electron microscopy studies showed that the concentration of nitric acid has great effects on the crystal structures of the initially formed nuclei and consequently the growth of gold NRs. A mechanism based on the effect of nitrate ions on surfactant micelle elongation and Ostwald ripening process is proposed for the growth of high AR gold NRs. The biocompatibility of high AR NRs was evaluated on primary human monocyte derived dendritic cells (MDDCs), and compared with that of spherical gold nanoparticles (NPs) and low AR NRs. Low AR (similar to 4.5) gold NRs induced considerable cell death due to CTAB, while spherical gold NPs (7 nm) and high AR (similar to 21) gold NRs showed no or minor effects on viability and immune regulatory markers, which supports the further development of high AR gold NRs for medical applications.
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| 10. |
- Ye, Fei, et al.
(författare)
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Uniform mesoporous silica coated iron oxide nanoparticles as a highly efficient, nontoxic MRI T 2 contrast agent with tunable proton relaxivities
- 2012
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Ingår i: Contrast Media & Molecular Imaging. - : Wiley. - 1555-4309 .- 1555-4317. ; 7:5, s. 460-468
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Tidskriftsartikel (refereegranskat)abstract
- Monodisperse mesoporous silica (mSiO 2) coated superparamagnetic iron oxide (Fe 3O 4@mSiO 2) nanoparticles (NPs) have been developed as a potential magnetic resonance imaging (MRI) T 2 contrast agent. To evaluate the effect of surface coating on MRI contrast efficiency, we examined the proton relaxivities of Fe 3O 4@mSiO 2 NPs with different coating thicknesses. It was found that the mSiO 2 coating has a significant impact on the efficiency of Fe 3O 4 NPs for MRI contrast enhancement. The efficiency increases with the thickness of mSiO 2 coating and is much higher than that of the commercial contrast agents. Nuclear magnetic resonance (NMR) relaxometry of Fe 3O 4@mSiO 2 further revealed that mSiO 2 coating is partially permeable to water molecules and therefore induces the decrease of longitudinal relaxivity, r 1. Biocompatibility evaluation of various sized (ca. 35-95 nm) Fe 3O 4@mSiO 2 NPs was tested on OC-k3 cells and the result showed that these particles have no negative impact on cell viability. The enhanced MRI efficiency of Fe 3O 4@mSiO 2 highlights these core-shell particles as highly efficient T 2 contrast agents with high biocompatibility.
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