Internalization of Auger electron-emitting isotopes into cancer cells: a method for spatial distribution determination of equivalent source terms.

Purpose: A challenge for single-cell dosimetry of internalized Auger electron-emitting (AE) radiopharmaceuticals remains how best to elucidate their spatial distribution. To this end, a method, photoresist autoradiography (PAR), was previously developed to identify the lateral spatial distribution of AE-emitting radionuclides internalized in single cancer cells. In this paper, we present a simple mathematical model based on the radius and depth of radiation-induced patterns in photoresist material to identify the location in the z-plane of an In source capable of generating the pattern.

A gecko skin micro/nano structure - A low adhesion, superhydrophobic, anti-wetting, self-cleaning, biocompatible, antibacterial surface.

Geckos, and specifically their feet, have attracted significant attention in recent times with the focus centred around their remarkable adhesional properties. Little attention however has been dedicated to the other remaining regions of the lizard body. In this paper we present preliminary investigations into a number of notable interfacial properties of the gecko skin focusing on solid and aqueous interactions.

Removal mechanisms of dew via self-propulsion off the gecko skin.

Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri.

Characterization of single α-tracks by photoresist detection and AFM analysis-focus on biomedical science and technology.

The interactions between energetic ions and biological and/or organic target materials have recently attracted theoretical and experimental attention, due to their implications for detector and device technologies, and for therapeutic applications. Most of the attention has focused on detection of the primary ionization tracks, and their effects, while recoil target atom tracks remain largely unexplored. Detection of tracks by a negative tone photoresist (SU-8), followed by standard development, in combination with analysis by atomic force microscopy, shows that both primary and recoil tracks are revealed as conical spikes, and can be characterized at high spatial resolution.

Nanographene oxide-based radioimmunoconstructs for in vivo targeting and SPECT imaging of HER2-positive tumors.

Nanographene oxide (NGO) is a novel nano-wall material that tracks to tumors in vivo, and which, as a consequence of its large surface area, has the capacity to carry a large payload. This study explores the use of anti-HER2 antibody (trastuzumab)-conjugated NGO, radiolabeled with (111)In-benzyl-diethylenetriaminepentaacetic acid (BnDTPA) via ππ-stacking, for functional imaging. In two HER2-overexpressing murine models of human breast cancer, high tumor-to-muscle ratio was achieved, resulting in clear visualization of tumor using single-photon emission computed tomography (SPECT).

Photoresists as a high spatial resolution autoradiography substrate for quantitative mapping of intra- and sub-cellular distribution of Auger electron emitting radionuclides.

Purpose: To explore poly(methyl methacrylate) (PMMA950) as an autoradiography substrate.

Materials And Methods: PMMA950 was spin coated onto a silicon substrate. Resists were exposed to either a 25 or 50 keV electron beam (e-beam) with fluences of 0.

Chemically amplified photoresist for high resolution autoradiography in targeted radiotherapy.

Evaluation of the intracellular distribution of radionuclides used for targeted radiotherapy (tRT) is essential for accurate dosimetry. Therefore, a direct and quantitative method for subcellular micro-autoradiography using radiation sensitive polymers (PMMA, UV1116 and AZ40XT) was developed. The electron exposure dose in radio-labelled cells due to Auger and internal conversion (IC) electron emissions of indium (¹¹¹In), a radionuclide currently used for tRT, was calculated using Monte Carlo (MC) simulation.

Measuring anisotropic friction on WTe2 using atomic force microscopy in the force-distance and friction modes.

Layered materials which can be easily cleaved have proved to be excellent samples for the study of atomic scale friction. The layered transition metal dichalcogenides have been particularly popular. These materials exhibit a number of interesting properties ranging from superconductivity to low frictional coefficients.

Putative functions and functional efficiency of ordered cuticular nanoarrays on insect wings.

The putative functions and functional efficiencies of periodic nanostructures on the surface of cicada wings have been investigated by atomic force microscopy (AFM) used as a tool for imaging, manipulation, and probing of adhesion. The structures consist of hexagonal close-packed protrusions with a lateral spacing of approximately 200 nm and may have multiple functionalities. Not only do the structures confer survival value by virtue of camouflage, but they may also serve as antiwetting and self-cleaning surfaces and thus be resistant to contamination.

A review of enabling technologies based on scanning probe microscopy relevant to bioanalysis.

The scanning probe microscope (SPM) system is emerging as an increasingly important tool for non-intrusive interrogation of biomolecular systems in vitro. Its particular merit is that it retains complete functionality in a biocompatible fluid environment and can track the dynamics of cellular and molecular processes in real time and real space at nm resolution, as an imaging tool, and with pN force-sensing/imposing resolution, as an interaction tool. The capability may have relevance as a test bed for monitoring cellular response to environmental stimuli and pharmaceutical intervention.

Calibration of AFM cantilever spring constants.

In this paper we present two simple, reliable and readily applicable methods for calibrating cantilevers and measuring the thickness of thin gold films. The spring constant calibration requires knowledge of the Young's modulus, density of the cantilever and resonant frequency. The thickness of thin gold layers was determined by measuring changes in the resonant frequency and Q-factor of beam shaped AFM cantilevers before and after coating.