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British Journal of Cancer Apr 2023Numerous studies have demonstrated the higher biological efficacy of carbon-ion irradiation (C-ions) and their ballistic precision compared with photons. At the... (Review)
Review
Numerous studies have demonstrated the higher biological efficacy of carbon-ion irradiation (C-ions) and their ballistic precision compared with photons. At the nanometre scale, the reactive oxygen species (ROS) produced by radiation and responsible for the indirect effects are differentially distributed according to the type of radiation. Photon irradiation induces a homogeneous ROS distribution, whereas ROS remain condensed in clusters in the C-ions tracks. Based on this linear energy transfer-dependent differential nanometric ROS distribution, we propose that the higher biological efficacy and specificities of the molecular response to C-ions rely on a 'stealth-bomber' effect. When biological targets are on the trajectories of the particles, the clustered radicals in the tracks are responsible for a 'bomber' effect. Furthermore, the low proportion of ROS outside the tracks is not able to trigger the cellular mechanisms of defence and proliferation. The ability of C-ions to deceive the cellular defence of the cancer cells is then categorised as a 'stealth' effect. This review aims to classify the biological arguments supporting the paradigm of the 'stealth-bomber' as responsible for the biological superiority of C-ions compared with photons. It also explains how and why C-ions will always be more efficient for treating patients with radioresistant cancers than conventional radiotherapy.
Topics: Humans; Reactive Oxygen Species; Neoplasms; Photons; Ions; Carbon
PubMed: 36639527
DOI: 10.1038/s41416-022-02117-6 -
Biosensors Jun 2022Noninvasive manipulation of nanoscopic species in liquids has attracted considerable attention due to its potential applications in diverse fields. Many sophisticated...
Noninvasive manipulation of nanoscopic species in liquids has attracted considerable attention due to its potential applications in diverse fields. Many sophisticated methodologies have been developed to control and study nanoscopic entities, but the low-power, cost-effective, and versatile manipulation of nanometer-sized objects in liquids remains challenging. Here, we present a dielectrophoretic (DEP) manipulation technique based on nanogap electrodes, with which the on-demand capturing, enriching, and sorting of nano-objects in microfluidic systems can be achieved. The dielectrophoretic control unit consists of a pair of swelling-induced nanogap electrodes crossing a microchannel, generating a steep electric field gradient and thus strong DEP force for the effective manipulation of nano-objects microfluidics. The trapping, enriching, and sorting of nanoparticles and DNAs were performed with this device to demonstrate its potential applications in micro/nanofluidics, which opens an alternative avenue for the non-invasive manipulation and characterization of nanoparticles such as DNA, proteins, and viruses.
Topics: DNA; Electrodes; Electrophoresis; Microfluidics; Proteins
PubMed: 35884255
DOI: 10.3390/bios12070451 -
Nanotechnology Mar 2016For a science to become a technology, a certain level of control has to have been established over the way items are fabricated for manufacture and use. Here we first...
For a science to become a technology, a certain level of control has to have been established over the way items are fabricated for manufacture and use. Here we first consider the challenge of making and using a LEGO(®) brick scaled down by a factor of 10(n) for n = 0-6 in each spatial dimension, i.e. from millimetres to nanometres. We consider both the manufacture and the subsequent properties of the nanobricks that pertain to their use in constructing and dismantling structures. As n increases, the ability to use fails first, to manufacture fails second and to fabricate fails last. Applied to the vast literature in nanoscience, this process emphasises the unmanufacturability of most nanoscale artefacts.
PubMed: 26871372
DOI: 10.1088/0957-4484/27/11/112501 -
PloS One 2022Single molecule localization microscopy (SMLM) has the potential to resolve structural details of biological samples at the nanometer length scale. Compared to room...
Single molecule localization microscopy (SMLM) has the potential to resolve structural details of biological samples at the nanometer length scale. Compared to room temperature experiments, SMLM performed under cryogenic temperature achieves higher photon yields and, hence, higher localization precision. However, to fully exploit the resolution it is crucial to account for the anisotropic emission characteristics of fluorescence dipole emitters with fixed orientation. In case of slight residual defocus, localization estimates may well be biased by tens of nanometers. We show here that astigmatic imaging in combination with information about the dipole orientation allows to extract the position of the dipole emitters without localization bias and down to a precision of 1 nm, thereby reaching the corresponding Cramér Rao bound. The approach is showcased with simulated data for various dipole orientations, and parameter settings realistic for real life experiments.
Topics: Algorithms; Biological Phenomena; Cold Temperature; Fluorescence; Likelihood Functions; Microscopy; Microscopy, Fluorescence; Normal Distribution; Photons; Probability; Reproducibility of Results; Single Molecule Imaging; Temperature
PubMed: 35120171
DOI: 10.1371/journal.pone.0263500 -
Journal of the American Chemical Society Nov 2022Nanoparticle interactions with cellular membranes are controlled by molecular recognition reactions and regulate a multitude of biological processes, including virus...
Nanoparticle interactions with cellular membranes are controlled by molecular recognition reactions and regulate a multitude of biological processes, including virus infections, biological nanoparticle-mediated cellular communication, and drug delivery applications. Aided by the design of various supported cell membrane mimics, multiple methods have been employed to investigate these types of interactions, revealing information on nanoparticle coverage, interaction kinetics, as well as binding strength; however, precise quantification of the separation distance across which these delicate interactions occur remains elusive. Here, we demonstrate that carefully designed neutron reflectometry (NR) experiments followed by an attentive selection and application of suitable theoretical models offer a means to quantify the distance separating biological nanoparticles from a supported lipid bilayer (SLB) with sub-nanometer precision. The distance between the nanoparticles and SLBs was tuned by exploiting either direct adsorption or specific binding using DNA tethers with different conformations, revealing separation distances of around 1, 3, and 7 nm with nanometric accuracy. We also show that NR provides precise information on nanoparticle coverage, size distribution, material composition, and potential structural changes in the underlying planar SLB induced upon nanoparticle binding. The precision with which these parameters could be quantified should pave an attractive path for investigations of the interactions between nanoparticles and interfaces at length scales and resolutions that were previously inaccessible. This thus makes it possible to, for example, gain an in-depth understanding of the molecular recognition reactions of inorganic and biological nanoparticles with cellular membranes.
Topics: Lipid Bilayers; Cell Membrane; Nanoparticles; Adsorption; Neutrons
PubMed: 36326176
DOI: 10.1021/jacs.2c08456 -
Proceedings of the National Academy of... Aug 2022We employed in a correlative manner an unconventional combination of methods, comprising cathodoluminescence, cryo-scanning electron microscopy (SEM), and cryo-focused...
We employed in a correlative manner an unconventional combination of methods, comprising cathodoluminescence, cryo-scanning electron microscopy (SEM), and cryo-focused ion beam (FIB)-SEM, to examine the volumes of thousands of cubed micrometers from rabbit atherosclerotic tissues, maintained in close-to-native conditions, with a resolution of tens of nanometers. Data from three different intralesional regions, at the media-lesion interface, in the core, and toward the lumen, were analyzed following segmentation and volume or surface representation. The media-lesion interface region is rich in cells and lipid droplets, whereas the core region is markedly richer in crystals and has lower cell density. In the three regions, thin crystals appear to be associated with intracellular or extracellular lipid droplets and multilamellar bodies. Large crystals are independently positioned in the tissue, not associated with specific cellular components. This extensive evidence strongly supports the idea that the lipid droplet surfaces and the outer membranes of multilamellar bodies play a role in cholesterol crystal nucleation and growth and that crystal formation occurs, in part, inside cells. The correlative combination of methods that allowed the direct examination of cholesterol crystals and lipid deposits in the atherosclerotic lesions may be similarly used for high-resolution examination of other tissues containing pathological or physiological cholesterol deposits.
Topics: Animals; Atherosclerosis; Cholesterol; Cryoelectron Microscopy; Imaging, Three-Dimensional; Microscopy, Electron, Scanning; Nanotechnology; Rabbits
PubMed: 35939716
DOI: 10.1073/pnas.2205475119 -
Nature Sep 2022Polymer membranes are widely used in separation processes including desalination, organic solvent nanofiltration and crude oil fractionation. Nevertheless, direct...
Polymer membranes are widely used in separation processes including desalination, organic solvent nanofiltration and crude oil fractionation. Nevertheless, direct evidence of subnanometre pores and a feasible method of manipulating their size is still challenging because of the molecular fluctuations of poorly defined voids in polymers. Macrocycles with intrinsic cavities could potentially tackle this challenge. However, unfunctionalized macrocycles with indistinguishable reactivities tend towards disordered packing in films hundreds of nanometres thick, hindering cavity interconnection and formation of through-pores. Here, we synthesized selectively functionalized macrocycles with differentiated reactivities that preferentially aligned to create well-defined pores across an ultrathin nanofilm. The ordered structure was enhanced by reducing the nanofilm thickness down to several nanometres. This orientated architecture enabled direct visualization of subnanometre macrocycle pores in the nanofilm surfaces, with the size tailored to ångström precision by varying the macrocycle identity. Aligned macrocycle membranes provided twice the methanol permeance and higher selectivity compared to disordered counterparts. Used in high-value separations, exemplified here by enriching cannabidiol oil, they achieved one order of magnitude faster ethanol transport and threefold higher enrichment than commercial state-of-the-art membranes. This approach offers a feasible strategy for creating subnanometre channels in polymer membranes, and demonstrates their potential for accurate molecular separations.
PubMed: 36045237
DOI: 10.1038/s41586-022-05032-1 -
Science Advances Apr 2021Proper immune responses are critical for successful biomaterial implantation. Here, four scales of honeycomb-like TiO structures were custom made on titanium (Ti)...
Proper immune responses are critical for successful biomaterial implantation. Here, four scales of honeycomb-like TiO structures were custom made on titanium (Ti) substrates to investigate cellular behaviors of RAW 264.7 macrophages and their immunomodulation on osteogenesis. We found that the reduced scale of honeycomb-like TiO structures could significantly activate the anti-inflammatory macrophage phenotype (M2), in which the 90-nanometer sample induced the highest expression level of CD206, , and and released the highest amount of among other scales. Afterward, the resulting immune microenvironment favorably triggered osteogenic differentiation of murine mesenchymal stem cells in vitro and subsequent implant-to-bone osteointegration in vivo. Furthermore, transcriptomic analysis revealed that the minimal scale of TiO honeycomb-like structure (90 nanometers) facilitated macrophage filopodia formation and up-regulated the Rho family of guanosine triphosphatases (), which reinforced the polarization of macrophages through the activation of the RhoA/Rho-associated protein kinase signaling pathway.
PubMed: 33811079
DOI: 10.1126/sciadv.abf6654 -
Discover Nano May 2024Nanofiltration (NF) and reverse osmosis (RO) processes are physical separation technologies used to remove contaminants from liquid streams by employing dense... (Review)
Review
Nanofiltration (NF) and reverse osmosis (RO) processes are physical separation technologies used to remove contaminants from liquid streams by employing dense polymer-based membranes with nanometric voids that confine fluids at the nanoscale. At this level, physical properties such as solvent and solute permeabilities are intricately linked to molecular interactions. Initially, numerous studies focused on developing macroscopic transport models to gain insights into separation properties at the nanometer scale. However, continuum-based models have limitations in nanoconfined situations that can be overcome by force field molecular simulations. Continuum-based models heavily rely on bulk properties, often neglecting critical factors like liquid structuring, pore geometry, and molecular/chemical specifics. Molecular/mesoscale simulations, while encompassing these details, often face limitations in time and spatial scales. Therefore, achieving a comprehensive understanding of transport requires a synergistic integration of both approaches through a multiscale approach that effectively combines and merges both scales. This review aims to provide a comprehensive overview of the state-of-the-art in multiscale modeling of transport through NF/RO membranes, spanning from the nanoscale to continuum media.
PubMed: 38771417
DOI: 10.1186/s11671-024-04020-w -
Nature Communications Jan 2017Over the last decade, two fields have dominated the attention of sub-diffraction photonics research: plasmonics and fluorescence nanoscopy. Nanoscopy based on...
Over the last decade, two fields have dominated the attention of sub-diffraction photonics research: plasmonics and fluorescence nanoscopy. Nanoscopy based on single-molecule localization offers a practical way to explore plasmonic interactions with nanometre resolution. However, this seemingly straightforward technique may retrieve false positional information. Here, we make use of the DNA origami technique to both control a nanometric separation between emitters and a gold nanoparticle, and as a platform for super-resolution imaging based on single-molecule localization. This enables a quantitative comparison between the position retrieved from single-molecule localization, the true position of the emitter and full-field simulations. We demonstrate that plasmonic coupling leads to shifted molecular localizations of up to 30 nm: a single-molecule mirage.
PubMed: 28074833
DOI: 10.1038/ncomms13966