| 1. |
- Barut, Inci, et al.
(författare)
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Cell and tissue imaging by secondary ion mass spectrometry
- 2023
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Ingår i: Biointerphases. - 1934-8630 .- 1559-4106. ; 18:6
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Tidskriftsartikel (refereegranskat)abstract
- This Tutorial focuses on the use of secondary ion mass spectrometry for the analysis of cellular and tissue samples. The Tutorial aims to cover the considerations in sample preparation analytical set up and some specific aspects of data interpretation associated with such analysis.
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| 2. |
- Evenbratt, Hanne, 1980, et al.
(författare)
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ToF-SIMS imaging of dual biomolecular monolayer gradients
- 2020
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Ingår i: Biointerphases. - : American Vacuum Society. - 1559-4106 .- 1934-8630. ; 15:6
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Tidskriftsartikel (refereegranskat)abstract
- Precise characterization of a monolayer of two different biomolecules in a gradient pattern on a glass surface puts high demand on the method used. Some techniques can detect protein monolayers but not on a glass surface. Others can distinguish between different proteins but not identify a gradient pattern. Here, we used ToF-SIMS to validate the complete surface composition, checking all the necessary boxes. As these types of surfaces can dictate sensitive cell behaviors, the precision on a nanolevel is crucial, and to visualize and determine the molecular distribution become essential. The dual monolayer consisted of laminin 521 and one of three other biomolecules of different sizes, epidermal growth factor, growth differentiation factor 5, or bovine serum albumin, creating opposing gradient patterns. The resulting ToF-SIMS imaging and line scan data provided detailed information on the distribution of the adsorbed proteins.
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| 3. |
- Gunnarsson, Stefán Bragi, et al.
(författare)
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Dual topography of laminin corona on gallium arsenide nanowires
- 2020
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Ingår i: Biointerphases. - : American Vacuum Society. - 1934-8630 .- 1559-4106. ; 15:5
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Tidskriftsartikel (refereegranskat)abstract
- Nanowires (NWs) are novel nanomaterials with applications in everything from medical implants to solar cells. With increasing number of applications, it is increasingly likely that organisms are exposed to these materials either intentionally or by accident. It is, therefore, important to study their interactions with biological systems and biomolecules. Upon exposure to biological fluids, nanostructure surfaces are quickly covered by a biomolecule corona. The composition of the corona determines the nanostructure's biological fate. Furthermore, upon adsorption, the protein structure can be affected. In order to study the corona morphology, we used two model proteins, laminin of the extracellular matrix and the immune system enzyme myeloperoxidase. We image the protein corona directly by cryo-TEM and enhance resolution by labeling the corona with activated gold nanoparticles. Three-dimensional imaging of the protein corona further increases the resolution and reveals irregularities in corona topography. By doing so, we identified bimodal distribution of spacing between gold nanoparticles and the NW surface for laminin corona at 58 and 85 nm distance from the NWs' surface. The dual topography of the corona is adding a new complexity of the protein corona surface and its interactions with the surrounding biology.
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| 4. |
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| 5. |
- Nie, Heng-Yong, et al.
(författare)
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Detection of gold cysteine thiolate complexes on gold nanoparticles with time-of-flight secondary ion mass spectrometry
- 2021
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Ingår i: Biointerphases. - : AMER INST PHYSICS. - 1934-8630 .- 1559-4106. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- Gold (Au) nanoparticles (NPs) are widely used in nanomedical applications as a carrier for molecules designed for different functionalities. Previous findings suggested that biological molecules, including amino acids, could contribute to the dissolution of Au NPs in physiological environments and that this phenomenon was size-dependent. We, therefore, investigated the interactions of L-cysteine with 5-nm Au NPs by means of time-of-flight secondary ion mass spectrometry (ToF-SIMS). This was achieved by loading Au NPs on a clean aluminum (Al) foil and immersing it in an aqueous solution containing L-cysteine. Upon rinsing off the excessive cysteine molecules, ToF-SIMS confirmed the formation of gold cysteine thiolate via the detection of not only the Au-S bond but also the hydrogenated gold cysteine thiolate molecular ion. The presence of NaCl or a 2-(N-morpholino)ethanesulfonic acid buffer disabled the detection of Au NPs on the Al foil. The detection of larger (50-nm) Au NPs was possible but resulted in weaker cysteine and gold signals, and no detected gold cysteine thiolate signals. Nano-gold specific adsorption of L-cysteine was also demonstrated by cyclic voltammetry using paraffine-impregnated graphite electrodes with deposited Au NPs. We demonstrate that the superior chemical selectivity and surface sensitivity of ToF-SIMS, via detection of elemental and molecular species, provide a unique ability to identify the adsorption of cysteine and formation of gold-cysteine bonds on Au NPs.
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| 6. |
- Nilsson, Kelly Dimovska, et al.
(författare)
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TOF-SIMS imaging reveals tumor heterogeneity and inflammatory response markers in the microenvironment of basal cell carcinoma
- 2020
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Ingår i: Biointerphases. - : American Vacuum Society. - 1934-8630 .- 1559-4106. ; 15:4
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Tidskriftsartikel (refereegranskat)abstract
- Basal cell carcinoma (BCC) is the most common skin malignancy. In fact, it is as common as the sum of all other skin malignancies combined and the incidence is rising. In this focused and histology-guided study, tissue from a patient diagnosed with aggressive BCC was analyzed by imaging mass spectrometry in order to probe the chemistry of the complex tumor environment. Time-of-flight secondary ion mass spectrometry using a (CO2)(6 k)(+)gas cluster ion beam allowed a wide range of lipid species to be detected. Their distributions were then imaged in the tissue that contained small tumor islands that were histologically classified as more/less aggressive. Maximum autocorrelation factor (MAF) analysis highlighted chemical differences between the tumors and the surrounding stroma. A closer inspection of the distribution of individual ions, selected based on the MAF loadings, showed heterogeneity in signal between different microtumors, suggesting the potential of chemically grading the aggressiveness of each individual tumor island. Sphingomyelin lipids were found to be located in stroma containing inflammatory cells.
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| 7. |
- Paul, Alexandra, 1988, et al.
(författare)
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Effect of ambient temperature on respiratory tract cells exposed to SARS-CoV-2 viral mimicking nanospheres - An experimental study
- 2021
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Ingår i: Biointerphases. - : American Vacuum Society. - 1559-4106 .- 1934-8630. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- The novel coronavirus caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached more than 160 countries and has been declared a pandemic. SARS-CoV-2 infects host cells by binding to the angiotensin-converting enzyme 2 (ACE-2) surface receptor via the spike (S) receptor-binding protein (RBD) on the virus envelope. Global data on a similar infectious disease spread by SARS-CoV-1 in 2002 indicated improved stability of the virus at lower temperatures facilitating its high transmission in the community during colder months (December–February). Seasonal viral transmissions are strongly modulated by temperatures, which can impact viral trafficking into host cells; however, an experimental study of temperature-dependent activity of SARS-CoV-2 is still lacking. We mimicked SARS-CoV-2 with polymer beads coated with the SARS-CoV-2 S protein to study the effect of seasonal temperatures on the binding of virus-mimicking nanospheres to lung epithelia. The presence of the S protein RBD on nanosphere surfaces led to binding by Calu-3 airway epithelial cells via the ACE-2 receptor. Calu-3 and control fibroblast cells with S-RBD-coated nanospheres were incubated at 33 and 37 °C to mimic temperature fluctuations in the host respiratory tract, and we found no temperature dependence in contrast to nonspecific binding of bovine serum ablumin-coated nanospheres. Moreover, the ambient temperature changes from 4 to 40 °C had no effect on S-RBD-ACE-2 ligand-receptor binding and minimal effect on the S-RBD protein structure (up to 40 °C), though protein denaturing occurred at 51 °C. Our results suggest that ambient temperatures from 4 to 40 °C have little effect on the SARS-CoV-2-ACE-2 interaction in agreement with the infection data currently reported.
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| 8. |
- Sun, Kangdi, et al.
(författare)
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Insight into the assembly of lipid-hyaluronan complexes in osteoarthritic conditions
- 2023
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Ingår i: Biointerphases. - : American Institute of Physics Inc.. - 1934-8630 .- 1559-4106. ; 18:2
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Tidskriftsartikel (refereegranskat)abstract
- Interactions between molecules in the synovial fluid and the cartilage surface may play a vital role in the formation of adsorbed films that contribute to the low friction of cartilage boundary lubrication. Osteoarthritis (OA) is the most common degenerative joint disease. Previous studies have shown that in OA-diseased joints, hyaluronan (HA) not only breaks down resulting in a much lower molecular weight (MW), but also its concentration is reduced ten times. Here, we have investigated the structural changes of lipid-HA complexes as a function of HA concentration and MW to simulate the physiologically relevant conditions that exist in healthy and diseased joints. Small angle neutron scattering and dynamic light scattering were used to determine the structure of HA-lipid vesicles in bulk solution, while a combination of atomic force microscopy and quartz crystal microbalance was applied to study their assembly on a gold surface. We infer a significant influence of both MW and HA concentrations on the structure of HA-lipid complexes in bulk and assembled on a gold surface. Our results suggest that low MW HA cannot form an amorphous layer on the gold surface, which is expected to negatively impact the mechanical integrity and longevity of the boundary layer and could contribute to the increased wear of the cartilage that has been reported in joints diseased with OA. © 2023 Author(s).
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