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Pharmaceutics Oct 2022Antipsychotic drugs have numerous disabling side effects, and many are lipophilic, making them hard to formulate at high strength. Incorporating them into nanometric... (Review)
Review
Antipsychotic drugs have numerous disabling side effects, and many are lipophilic, making them hard to formulate at high strength. Incorporating them into nanometric emulsions can increase their solubility, protect them from degradation, and increase their brain delivery, being a promising strategy to overcome the current treatment gap. A thorough review was performed to assess the true potential of these formulations for antipsychotic drugs brain delivery. Intranasal administration was preferred when compared to oral or intravenous administration, since it allowed for direct brain drug transport and reduced systemic drug distribution, having increased efficacy and safety. Moreover, the developed systems increased antipsychotic drug solubility up to 4796 times (when compared to water), which is quite substantial. In the in vivo experiments, nanometric emulsions performed better than drug solutions or suspensions, leading to improved brain drug targeting, mainly due to these formulation's excipients (surfactants and cosolvents) permeation enhancing capability, added to a small droplet size, which leaves a large surface area available for drug absorption to occur. Thus, even if it is difficult to conclude on which formulation composition leads to a best performance (high number of variables), overall nanometric emulsions have proven to be promising strategies to improve brain bioavailability of antipsychotic drugs.
PubMed: 36297609
DOI: 10.3390/pharmaceutics14102174 -
Chemical Society Reviews Apr 2021Nanopores in solid-state membranes are promising for a wide range of applications including DNA sequencing, ultra-dilute analyte detection, protein analysis, and polymer... (Review)
Review
Nanopores in solid-state membranes are promising for a wide range of applications including DNA sequencing, ultra-dilute analyte detection, protein analysis, and polymer data storage. Techniques to fabricate solid-state nanopores have typically been time consuming or lacked the resolution to create pores with diameters down to a few nanometres, as required for the above applications. In recent years, several methods to fabricate nanopores in electrolyte environments have been demonstrated. These in situ methods include controlled breakdown (CBD), electrochemical reactions (ECR), laser etching and laser-assisted controlled breakdown (la-CBD). These techniques are democratising solid-state nanopores by providing the ability to fabricate pores with diameters down to a few nanometres (i.e. comparable to the size of many analytes) in a matter of minutes using relatively simple equipment. Here we review these in situ solid-state nanopore fabrication techniques and highlight the challenges and advantages of each method. Furthermore we compare these techniques by their desired application and provide insights into future research directions for in situ nanopore fabrication methods.
PubMed: 33623941
DOI: 10.1039/d0cs00924e -
Accounts of Chemical Research May 2018Over the past decade, there has been growing interest in developing biosensors and devices with nanoscale and vertical topography. Vertical nanostructures induce... (Review)
Review
Over the past decade, there has been growing interest in developing biosensors and devices with nanoscale and vertical topography. Vertical nanostructures induce spontaneous cell engulfment, which enhances the cell-probe coupling efficiency and the sensitivity of biosensors. Although local membranes in contact with the nanostructures are found to be fully fluidic for lipid and membrane protein diffusions, cells appear to actively sense and respond to the surface topography presented by vertical nanostructures. For future development of biodevices, it is important to understand how cells interact with these nanostructures and how their presence modulates cellular function and activities. How cells recognize nanoscale surface topography has been an area of active research for two decades before the recent biosensor works. Extensive studies show that surface topographies in the range of tens to hundreds of nanometers can significantly affect cell functions, behaviors, and ultimately the cell fate. For example, titanium implants having rough surfaces are better for osteoblast attachment and host-implant integration than those with smooth surfaces. At the cellular level, nanoscale surface topography has been shown by a large number of studies to modulate cell attachment, activity, and differentiation. However, a mechanistic understanding of how cells interact and respond to nanoscale topographic features is still lacking. In this Account, we focus on some recent studies that support a new mechanism that local membrane curvature induced by nanoscale topography directly acts as a biochemical signal to induce intracellular signaling, which we refer to as the curvature hypothesis. The curvature hypothesis proposes that some intracellular proteins can recognize membrane curvatures of a certain range at the cell-to-material interface. These proteins then recruit and activate downstream components to modulate cell signaling and behavior. We discuss current technologies allowing the visualization of membrane deformation at the cell membrane-to-substrate interface with nanometer precision and demonstrate that vertical nanostructures induce local curvatures on the plasma membrane. These local curvatures enhance the process of clathrin-mediated endocytosis and affect actin dynamics. We also present evidence that vertical nanostructures can induce significant deformation of the nuclear membrane, which can affect chromatin distribution and gene expression. Finally, we provide a brief perspective on the curvature hypothesis and the challenges and opportunities for the design of nanotopography for manipulating cell behavior.
Topics: Actins; Cell Membrane; Gene Expression; Nanostructures; Nuclear Envelope; Polymerization; Signal Transduction; Surface Properties
PubMed: 29648779
DOI: 10.1021/acs.accounts.7b00594 -
Chemical Science Jul 2016Ultrathin materials at a sub-nanometer scale not only feature atomic scale size, but also possess unprecedented properties compared to conventional nanomaterials. The... (Review)
Review
Ultrathin materials at a sub-nanometer scale not only feature atomic scale size, but also possess unprecedented properties compared to conventional nanomaterials. The two aspects endow such materials with great potential. In sub-nanometric (SN) wires, the weak interactions may overwhelm the rigidity of inorganic compounds and dominate behaviours at this regime. Consequently intricate structures and polymer-like rheology can be obtained, shedding new light on chemistry as well as material design. As for 0D or 2D SN materials, clusters are analogous to molecules and SN sheets show unique electronic structures. Taking SN wire as an example, their growth mechanisms are discussed, as well as their applications and potentials. The chemistry at this regime can promote their application-oriented research, however, this is not yet well explored. In short, there is great potential at the sub-nanometer scale, although there are also many challenges ahead.
PubMed: 30155040
DOI: 10.1039/c6sc00432f -
Current Opinion in Structural Biology Dec 2022Membrane modulation is a key part of cellular life. Critical to processes like energy production, cell division, trafficking, migration and even pathogen entry, defects... (Review)
Review
Membrane modulation is a key part of cellular life. Critical to processes like energy production, cell division, trafficking, migration and even pathogen entry, defects in membrane modulation are often associated with diseases. Studying the molecular mechanisms of membrane modulation is challenging due to the highly dynamic nature of the oligomeric assemblies involved, which adopt multiple conformations depending on the precise event they are participating in. With the development of electron cryo-tomography and subtomogram averaging, many of these challenges are being resolved as it is now possible to observe complex macromolecular assemblies inside a cell at nanometre to sub-nanometre resolutions. Here, we review the different ways electron cryo-tomography is being used to help uncover the molecular mechanisms used by cells to shape their membranes.
Topics: Cryoelectron Microscopy; Electrons; Electron Microscope Tomography; Macromolecular Substances
PubMed: 36174286
DOI: 10.1016/j.sbi.2022.102464 -
Optics Express Jan 2021Single-molecule microscopy allows for the investigation of the dynamics of individual molecules and the visualization of subcellular structures at high spatial...
Single-molecule microscopy allows for the investigation of the dynamics of individual molecules and the visualization of subcellular structures at high spatial resolution. For single-molecule imaging experiments, and particularly those that entail the acquisition of multicolor data, calibration of the microscope and its optical components therefore needs to be carried out at a high level of accuracy. We propose here a method for calibrating a microscope at the nanometer scale, in the sense of determining optical aberrations as revealed by point source localization errors on the order of nanometers. The method is based on the imaging of a standard sample to detect and evaluate the amount of geometric aberration introduced in the optical light path. To provide support for multicolor imaging, it also includes procedures for evaluating the geometric aberration caused by a dichroic filter and the axial chromatic aberration introduced by an objective lens.
PubMed: 33362108
DOI: 10.1364/OE.408361 -
Nanoscale Advances Feb 2022Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent... (Review)
Review
Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent tunability of their magnetic properties. To optimize particles for a specific application, it is crucial to interrelate their performance with their structural and magnetic properties. This review presents the advantages of small-angle X-ray and neutron scattering techniques for achieving a detailed multiscale characterization of magnetic nanoparticles and their ensembles in a mesoscopic size range from 1 to a few hundred nanometers with nanometer resolution. Both X-rays and neutrons allow the ensemble-averaged determination of structural properties, such as particle morphology or particle arrangement in multilayers and 3D assemblies. Additionally, the magnetic scattering contributions enable retrieving the internal magnetization profile of the nanoparticles as well as the inter-particle moment correlations caused by interactions within dense assemblies. Most measurements are used to determine the time-averaged ensemble properties, in addition advanced small-angle scattering techniques exist that allow accessing particle and spin dynamics on various timescales. In this review, we focus on conventional small-angle X-ray and neutron scattering (SAXS and SANS), X-ray and neutron reflectometry, gracing-incidence SAXS and SANS, X-ray resonant magnetic scattering, and neutron spin-echo spectroscopy techniques. For each technique, we provide a general overview, present the latest scientific results, and discuss its strengths as well as sample requirements. Finally, we give our perspectives on how future small-angle scattering experiments, especially in combination with micromagnetic simulations, could help to optimize the performance of magnetic nanoparticles for specific applications.
PubMed: 36131777
DOI: 10.1039/d1na00482d -
Reports on Progress in Physics.... May 2017Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when...
Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds (1 attosecond = 1 as = 10 s), which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is ∼152 as. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this report on progress we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as above-threshold ionization and high-order harmonic generation. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nanophysics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the induced fields and the unique electron dynamics initiated by them with high temporal and spatial resolution.
PubMed: 28059773
DOI: 10.1088/1361-6633/aa574e -
Advanced Science (Weinheim,... Jan 2022Sub-nanometric materials (SNMs) are an attractive scope in recent years due to their atomic-level size and unique properties. Among various performances of SNMs,... (Review)
Review
Sub-nanometric materials (SNMs) are an attractive scope in recent years due to their atomic-level size and unique properties. Among various performances of SNMs, photothermal energy conversion is one of the most important ones because it can efficiently utilize the light energy. Herein, the SNMs with photothermal energy conversion behaviors and their applications are reviewed. First, a hydrothermal/solvothermal method for the synthesis of SNMs is systematically discussed, including the LaMer pathway and the cluster-nuclei coassembly pathway. Based on this synthetic strategy, many kinds of SNMs with different morphologies are successfully prepared, such as nanorings, nanowires, nanosheets, and nanobelts. These SNMs exhibit excellent photothermal performance under the laser or solar irradiation according to their different light absorption ranges. These enhanced absorption performances of SNMs are induced by the mechanism of plasmonic localized heating or nonradiative relaxation. Finally, the applications of the photothermal SNMs are illustrated. The SNMs with photothermal behaviors can be widely applied in the fields of solar vapor generation, biomedicine, and light-responsive composites construction. It is hoped that this review can provide new viewpoints and profound understanding to the SNMs in photothermal energy conversion.
PubMed: 34837484
DOI: 10.1002/advs.202104225 -
Current Opinion in Chemical Biology Mar 2024Super-resolution microscopy (SRM) has transformed our understanding of proteins' subcellular organization and revealed cellular details down to nanometers, far beyond... (Review)
Review
Super-resolution microscopy (SRM) has transformed our understanding of proteins' subcellular organization and revealed cellular details down to nanometers, far beyond conventional microscopy. While localization precision is independent of the number of fluorophores attached to a biomolecule, labeling density is a decisive factor for resolving complex biological structures. The average distance between adjacent fluorophores should be less than half the desired spatial resolution for optimal clarity. While this was not a major limitation in recent decades, the success of modern microscopy approaching molecular resolution down to the single-digit nanometer range will depend heavily on advancements in fluorescence labeling. This review highlights recent advances and challenges in labeling strategies for SRM, focusing on site-specific labeling technologies. These advancements are crucial for improving SRM precision and expanding our understanding of molecular interactions.
PubMed: 38490137
DOI: 10.1016/j.cbpa.2024.102445