A biological nanofoam: The wall of coniferous bisaccate pollen

Cojocaru, Ruxandra; Mannix, Oonagh; Capron, Marie; Miller, C. Giles; Jouneau, Pierre-Henri; Gallet, Benoît; Falconet, Denis; Pacureanu, Alexandra; Stukins, Stephen

doi:10.1126/sciadv.abd0892

Cited by 13 publications

(6 citation statements)

References 60 publications

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“…Since the densities of these objects are slightly greater than 1 g/cm 3 , the quantities are close to the thickness, in micrometers. The diatom and pollen grain show large variations in projected density due to the porous structure of the diatom shell and the nanofoam structure of the pollen wall called the exine 26 . The cavities in this foam range in diameter from about 0.5 µm to 2 µm and the thickness of the exine, apparent around the circumference of the projected image, is about 1 µm, consistent with X-ray phase-contrast tomography measurements of pine pollen 26 .…”

Section: Resultsmentioning

confidence: 99%

“…The diatom and pollen grain show large variations in projected density due to the porous structure of the diatom shell and the nanofoam structure of the pollen wall called the exine 26 . The cavities in this foam range in diameter from about 0.5 µm to 2 µm and the thickness of the exine, apparent around the circumference of the projected image, is about 1 µm, consistent with X-ray phase-contrast tomography measurements of pine pollen 26 . The spirulina has a structure of a helical wire of about 4 µm wire diameter with a coil pitch of 20 µm and coil diameter of about 10 µm.…”

Section: Resultsmentioning

confidence: 99%

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Dose-efficient scanning Compton X-ray microscopy

Dresselhaus

Ivanov

et al. 2023

Light Sci Appl

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The highest resolution of images of soft matter and biological materials is ultimately limited by modification of the structure, induced by the necessarily high energy of short-wavelength radiation. Imaging the inelastically scattered X-rays at a photon energy of 60 keV (0.02 nm wavelength) offers greater signal per energy transferred to the sample than coherent-scattering techniques such as phase-contrast microscopy and projection holography. We present images of dried, unstained, and unfixed biological objects obtained by scanning Compton X-ray microscopy, at a resolution of about 70 nm. This microscope was realised using novel wedged multilayer Laue lenses that were fabricated to sub-ångström precision, a new wavefront measurement scheme for hard X rays, and efficient pixel-array detectors. The doses required to form these images were as little as 0.02% of the tolerable dose and 0.05% of that needed for phase-contrast imaging at similar resolution using 17 keV photon energy. The images obtained provide a quantitative map of the projected mass density in the sample, as confirmed by imaging a silicon wedge. Based on these results, we find that it should be possible to obtain radiation damage-free images of biological samples at a resolution below 10 nm.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Dose-efficient scanning Compton X-ray microscopy

Dresselhaus

Ivanov

et al. 2023

Light Sci Appl

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show abstract

“…1), allowing exposures more than 6000 times stronger in the case of the pollen. Although it was not feasible for us to carry out phase-contrast X-ray imaging experiments on the same or similar samples, recent published results of holographic tomography of pine pollen grains 25 do offer this comparison. That work was carried out at the European Synchrotron Radiation Source (ESRF) using a photon energy of 12 keV, and yielded a resolution in all three dimensions similar to the two-dimensional resolution achieved here.…”

Section: Discussionmentioning

confidence: 99%

“…The diatom and pollen grain show large variations in projected density due to the porous structure of the diatom shell and the nanofoam structure of the pollen wall called the exine 25 . The cavities in this foam range in diameter from about 0.5 µm to 2 µm and the thickness of the exine, apparent around the circumference of the projected image, is about 1 µm, consistent with X-ray phasecontrast tomography measurements of pine pollen 25 . The spirulina has a structure of a helical wire of about 4 µm wire diameter with a coil pitch of 20 µm and coil diameter of about 10 µm.…”

Section: Compton Images Of Biological Objectsmentioning

confidence: 99%

Dose-efficient Scanning Compton X-ray Microscopy

Bajt¹,

Li²,

Dresselhaus³

et al. 2023

Preprint

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The highest resolution of images of soft matter and biological materials is ultimately limited by modification of the structure, induced by the necessarily high energy of short-wavelength radiation. Imaging the inelastically scattered X-rays at a photon energy of 60 keV (0.02 nm wavelength) offers greater signal per energy transferred to the sample than coherent-scattering techniques such as phase-contrast microscopy and projection holography. We present images of dried, unstained, and unfixed biological objects obtained by scanning Compton X-ray microscopy, at a resolution of about 40 nm. This microscope was realised using novel wedged multilayer Laue lenses that were fabricated to sub-ångström precision, a new wavefront measurement scheme for hard X rays, and efficient pixel-array detectors. The doses required to form these images were as little as 0.02% of the tolerable dose and 0.05% of that needed for phase-contrast imaging at similar resolution using 12 keV photon energy. The images obtained provide a quantitative map of the projected mass density in the sample, as confirmed by imaging a silicon wedge. Based on these results, we find that it should be possible to obtain radiation damage-free images of biological samples at a resolution below 10 nm.

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“…When the pollen reaches suitable soil, the inner seeds can break through the outer shell, take root, and germinate. [26,27] Pollen is also the first natural particle to be observed with Brownian motion. Encapsulating nanoparticles with a protective outer shell to form a shell-core structure like pollen may protect the drugs during delivery and prolong the half-life of drugs.…”

Section: Introductionmentioning

confidence: 99%

Pollen‐Inspired Shell–Core Aerosol Particles Capable of Brownian Motion for Pulmonary Vascularization

Chen

Xiang

et al. 2023

Advanced Materials

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Nebulization is the most widely used respiratory delivery technique with non‐invasive properties. However, nebulized drugs often fail to function due to the excretion and immune clearance of the respiratory system. In this work, inspired by pollen in nature, novel shell–core aerosol particles (APs) capable of Brownian motion are constructed for respiratory delivery. Drugs‐loaded poly(lactic‐co‐glycolic acid) nanoparticles are prepared by emulsification to form the inner core, and the membranes of macrophages are extracted to form the outer shell. The optimized size and the shell–core structure endow APs with Brownian motion and atomization stability, thus enabling the APs to reach the bronchi and alveoli deeply for effective deposition. Camouflaging the macrophage membranes equips the APs with immune evasion. In vitro experiments prove that deferoxamine (DFO)‐loaded APs (DFO@APs) can promote the angiogenesis of human umbilical vein endothelial cells. A hyperoxia‐induced bronchopulmonary dysplasia (BPD) model is constructed to validate the efficiency of DFO@APs. In BPD mice, DFO@APs can release DFO in the alveolar interstitium, thus promoting the reconstruction of microvasculature, ultimately inducing lung development for treating BPD. In conclusion, this study develops “pollen”‐inspired shell–core aerosol particles capable of Brownian motion, which provides a novel idea and theoretical basis for respiratory administration.

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A biological nanofoam: The wall of coniferous bisaccate pollen

Cited by 13 publications

References 60 publications

Dose-efficient scanning Compton X-ray microscopy

Dose-efficient scanning Compton X-ray microscopy

Dose-efficient Scanning Compton X-ray Microscopy

Pollen‐Inspired Shell–Core Aerosol Particles Capable of Brownian Motion for Pulmonary Vascularization

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