The influence of structure depth on image blurring of micrometres-thick specimens in MeV transmission electron imaging

Sample thickness affects contrast and measured shape in TEM images and in electron tomograms

We investigated the effect of nanoparticle (NP) image broadening and its contrast change dependence on a support matrix thickness in a transmission electron microscope (TEM). We measured the effect of NP size and atomic number on its image broadening. Based on the experimental TEM images we generated tomograms of NPs on four types of support matrix. The measured shape aspect ratio of the NPs in such tomograms depends on the geometry of the support matrix. For example, the aspect ratio of 6 nm NP placed on a thin film with window-frame support is 1.14, while the aspect ratio of 6 nm NP on a rod-shaped support with 910 nm diameter is 1.67 in a tomogram.

Intranasal Administration of Dolutegravir-Loaded Nanoemulsion-Based In Situ Gel for Enhanced Bioavailability and Direct Brain Targeting

Dolutegravir's therapeutic effectiveness in the management of neuroAIDS is mainly limited by its failure to cross the blood-brain barrier. However, lipid-based nanovesicles such as nanoemulsions have demonstrated their potential for the brain targeting of various drugs by intranasal delivery. Thus, the purpose of this study was to develop a Dolutegravir-loaded nanoemulsion-based in situ gel and evaluate its prospective for brain targeting by intranasal delivery. Dolutegravir-loaded nanoemulsions were prepared using dill oil, Tween^® 80, and Transcutol^® P. Optimization of the nanoemulsion particle size and drug release was carried out using a simplex lattice design. Formulations (F1-F7 and B1-B6) were assessed for various pharmaceutical characteristics. Ex vivo permeation and ciliotoxicity studies of selected in situ gels (B1) were conducted using sheep nasal mucosa. Drug targeting to the brain was assessed in vivo in rats following the nasal delivery of B1. The composition of oil, surfactant, and cosurfactant significantly (p < 0.05) influenced the dependent variables (particle size and % of drug release in 8 h). Formulation B1 exhibits pharmaceutical characteristics that are ideal for intranasal delivery. The mucosal steady-state flux noticed with BI was significantly greater (p < 0.005) than for the control gel. A histopathology of nasal mucosa treated with BI showed no signs of toxicity or cellular damage. Intranasal administration of B1 resulted in greater C_max (~six-fold, p < 0.0001) and AUC_0-α (~five-fold, p < 0.0001), and decreased T_max (1 h) values in the brain, compared to intravenous administration. Meantime, the drug level in the plasma was relatively low, suggesting less systemic exposure to Dolutegravir through intranasal delivery. In summary, the promising data observed here signifies the prospective of B1 to enhance the brain targeting of Dolutegravir by intranasal delivery and it could be used as a feasible and practicable strategy for the management of neuroAIDS.

Automatic system for electron tomography data collection in the ultra-high voltage electron microscope

In this study, we report an automatic system for collection of tilt series for electron tomography based on the ultra-HVEM in Osaka University. By remotely controlling the microscope and reading the observation image, the system can track the field of view and do focus in each tilt angle. The automatic tracking is carried out with an image matching technique based on normalized correlation coefficient. Auto focus is realized by the optimization of image sharpness. A toolkit that can expand the field of view with technique of image stitching is also developed. The system can automatically collect the tilt series with much smaller time consumption.