Comparison of NEXAFS microscopy and TEM-EELS for studies of soft matter

Hitchcock, Adam P.; Dynes, James J.; Johansson, Göran A.; Wang, Jian; Botton, Gianluigi A.

doi:10.1016/j.micron.2007.09.008

Cited by 95 publications

(80 citation statements)

References 37 publications

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“…51,52 To measure the extent of protein adsorption, the T protein was calculated. This calculation was based on the assumption that formation of a protein corona around NDs resembles a classical ligand binding model and thus follows the law 59 Soft X-rays also provide spatial resolution of 25-30 nm 60 and spectral resolution on the order of 100 meV 61,62 that can differentiate between classes of biomolecules and can identify NPs as therapeutic carriers in cells and tissues. 57 The spectrum of lys-NDs (red; Figure 3A) recorded as a reference shows identifiable peaks at 288.2 eV, 292.5 eV, and 297.5 eV, indicated by arrows, which are absent in the spectrum of intracellular proteins (green; Figure 3A) obtained from the untreated cells.…”

Section: Scanning Transmission X-ray Microscopymentioning

confidence: 99%

Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

Alwani¹,

Kaur²,

Michel³

et al. 2016

IJN

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Purpose Nanodiamonds (NDs) are emerging as an attractive tool for gene therapeutics. To reach their full potential for biological application, NDs should maintain their colloidal stability in biological milieu. This study describes the behavior of lysine-functionalized ND (lys-ND) in various dispersion media, with an aim to limit aggregation and improve the colloidal stability of ND-gene complexes called diamoplexes. Furthermore, cellular and macromolecular interactions of lys-NDs are also analyzed in vitro to establish the understanding of ND-mediated gene transfer in cells. Methods lys-NDs were synthesized earlier through covalent conjugation of lysine amino acid to carboxylated NDs surface generated through re-oxidation in strong oxidizing acids. In this study, dispersions of lys-NDs were prepared in various media, and the degree of sedimentation was monitored for 72 hours. Particle size distributions and zeta potential measurements were performed for a period of 25 days to characterize the physicochemical stability of lys-NDs in the medium. The interaction profile of lys-NDs with fetal bovine serum showed formation of a protein corona, which was evaluated by size and charge distribution measurements. Uptake of lys-NDs in cervical cancer cells was analyzed by scanning transmission X-ray microscopy, flow cytometry, and confocal microscopy. Cellular uptake of diamoplexes (complex of lys-NDs with small interfering RNA) was also analyzed using flow cytometry. Results Aqueous dispersion of lys-NDs showed minimum sedimentation and remained stable over a period of 25 days. Size distributions showed good stability, remaining under 100 nm throughout the testing period. A positive zeta potential of >+20 mV indicated a preservation of surface charges. Size distribution and zeta potential changed for lys-NDs after incubation with blood serum, suggesting an interaction with biomolecules, mainly proteins, and a possible formation of a protein corona. Cellular internalization of lys-NDs was confirmed by various techniques such as confocal microscopy, soft X-ray spectroscopy, and flow cytometry. Conclusion This study establishes that dispersion of lys-NDs in aqueous medium maintains long-term stability and also provides evidence that lysine functionalization enables NDs to interact effectively with the biological system to be used for RNAi therapeutics.

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Section: Scanning Transmission X-ray Microscopymentioning

confidence: 99%

Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

Alwani¹,

Kaur²,

Michel³

et al. 2016

IJN

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“…Radiation damage of polymers induced by X-rays, particularly soft X-rays, is attracting growing attention. [4][5][6][7][8][9][10][11] Better understanding of damage mechanisms and more accurate determinations of damage rates for polymers are not only important to the areas mentioned above, but also to the field of soft X-ray spectromicroscopy, which is increasingly being applied to organic materials [12][13][14][15] and biological samples. 14,16,17 A complete bibliography of soft X-ray spectromicroscopy has recently been published in association with a recent review of polymer applications 15 and updates can be obtained from http://unicorn.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of Radiation Damage to Polyethylene Terephthalate by Soft X-rays and High-energy Electrons

et al. 2009

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The chemical changes and absolute rates in radiation damage to polyethylene terephthalate (PET) caused by soft X-rays and energetic electrons have been measured using a scanning transmission X-ray microscope (STXM). Electron beam damage at two different dose rates and a range of doses was performed in an 80 keV transmission electron microscope (TEM). The STXM beam was used to create damage patterns with systematically varied doses of monochromatic soft X-rays on an adjacent piece of the same PET sample. NEXAFS spectroscopy at the C 1s and O 1s edges was used to study the chemistry of the radiation damage and to determine quantitative critical doses for PET damage by both types of radiation. The spectral changes were similar for damage by electrons and X-rays, indicating the radiation chemistry is dominated by secondary processes, not the primary event. The critical dose for chemical changes determined from C 1s spectral features is 4.2(6) × 10 8 Gy and was the same for soft X-rays and electrons within measurement uncertainties. The critical dose for specific damage processes (as defined by changes in several different, bond-specific spectral features) was found to be similar in the C 1s region and was comparable between C 1s and O 1s edges for electron beam damage. There were statistically different critical doses for soft X-ray damage as probed by changes in O 1s spectral features related to carbonyl and ester bonds.

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“…Compared to the electron microscope, XANES provides a combination of high energy resolution and low sample damage which has been shown to be extremely powerful for the study of functional groups in organic systems e.g. proteins and polymers [12,13]. Table 1.…”

Section: Analytical Temmentioning

confidence: 99%

Analytical transmission electron microscopy at organic interfaces

Goode¹,

Porter²,

Kłosowski³

et al. 2017

Current Opinion in Solid State and Materials Science

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Organic materials are ubiquitous in all aspects of our daily lives. Increasingly there is a need to understand interactions between different organic phases, or between organic and inorganic materials (hybrid interfaces), in order to gain fundamental knowledge about the origin of their structural and functional properties. In order to understand the complex structure-propertyprocessing relationships in (and between) these materials, we need tools that combine high chemical sensitivity with high spatial resolution to allow detailed interfacial characterisation. Analytical transmission electron microscopy (TEM) is a powerful and versatile technique that can fulfil both criteria. However, the application of analytical TEM to organic systems presents some unique challenges, such as low contrast between phases, and electron beam sensitivity. In this review recent analytical TEM approaches to the nanoscale characterisation of two systems will be discussed: the hybrid collagen/mineral interface in bone, and the all-organic donor/acceptor interface in OPV devices.

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Comparison of NEXAFS microscopy and TEM-EELS for studies of soft matter

Cited by 95 publications

References 37 publications

Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

Quantitative Evaluation of Radiation Damage to Polyethylene Terephthalate by Soft X-rays and High-energy Electrons

Analytical transmission electron microscopy at organic interfaces

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