Publications by authors named "Sebastian Thompson"

The new and unique possibilities that nanomaterials offer have greatly impacted biomedicine, from the treatment and diagnosis of diseases, to the specific and optimized delivery of therapeutic agents. Technological advances in the synthesis, characterization, standardization, and therapeutic performance of nanoparticles have enabled the approval of several nanomedicines and novel applications. Discoveries continue to rise exponentially in all disease areas, from cancer to neurodegenerative diseases.

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Correction for 'Label free localization of nanoparticles in live cancer cells using spectroscopic microscopy' by Graham L. C. Spicer , , 2018, , 19125-19130, https://doi.

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Temperature measurement at the nanoscale has brought insight to a wide array of research interests in modern chemistry, physics, and biology. These measurements have been enabled by the advent of nanothermometers, which relay nanoscale temperature information through the analysis of their intrinsic photophysical behavior. In the past decade, several nanothermometers have been developed including dyes, nanodiamonds, fluorescent proteins, nucleotides, and nanoparticles.

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In the last decade, technological advances in chemistry and photonics have enabled real-time measurement of temperature at the nanoscale. Nanothermometers, probes specifically designed to relay these nanoscale temperature changes, provide a high degree of temperature, temporal, and spatial resolution and precision. Several different approaches have been proposed, including microthermocouples, luminescence and fluorescence polarization anisotropy-based nanothermometers.

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Almost 15 years ago, the URI prefoldin-like complex was discovered by Krek and colleagues in immunoprecipitation experiments conducted in mammalian cells with the aim of identifying new binding partners of the E3 ubiquitin-protein ligase S-phase kinase-associated protein 2 (SKP2) (Gstaiger et al. Science 302(5648):1208-1212, 2003). The URI prefoldin-like complex is a heterohexameric chaperone complex comprising two α and four β subunits (α2β4).

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Gold nanoparticles (GNPs) have become essential tools used in nanobiotechnology due to their tunable plasmonic properties and low toxicity in biological samples. Among the available approaches for imaging GNPs internalized by cells, hyperspectral techniques stand out due to their ability to simultaneously image and perform spectral analysis of GNPs. Here, we present a study utilizing a recently introduced hyperspectral imaging technique, live-cell PWS, for the imaging, tracking, and spectral analysis of GNPs in live cancer cells.

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Photodynamic therapy (PDT) is a non-invasive treatment widely applied to different cancers. The goal of PDT is the photo-induced destruction of cancer cells by the activation of different cell death mechanisms, including apoptosis and/or necrosis. Recent efforts focusing on understanding the mechanisms of cell death activated by PDT find that it depends on the type of photosensitizer (PS), targeted organelles, and nature of the light used.

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A method is proposed for controlling the number of nanoparticles bound to cell membranes via RGDS peptide-integrin interactions. It consists of propelling nanoparticles bearing the peptides with enzymes (glucose oxidase), which disrupts biomolecular interactions as a function of the concentration of enzyme substrate (glucose).

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A universal method for inactivating enzymes on demand is introduced, which involves irradiating nanorod-bound enzymes with near-infrared light. The subsequent generation of plasmonic heat denatures the enzymes selectively without damaging other proteins or cell membranes present in the same solution.

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We previously established that spectroscopic microscopy can quantify subdiffraction-scale refractive index (RI) fluctuations in a label-free dielectric medium with a smooth surface. However, to study more realistic samples, such as biological cells, the effect of rough surface should be considered. In this Letter, we first report an analytical theory to synthesize microscopic images of a rough surface, validate this theory by finite-difference time-domain (FDTD) solutions of Maxwell's equations, and characterize the spectral properties of light reflected from a rough surface.

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The photophysical properties of a chlorin, isobacteriochlorin and bacteriochlorin built on a core tetrapentafluorophenylporphyrin (TPPF20 ) and the nonhydrolyzable para thioglycosylated conjugates of these chromophores are presented. The photophysical characterization of these compounds was done in three different solvents to correlate with different environments in cells and tissues. Compared with TPPF20 other dyes have greater absorption in the red region of the visible spectrum and greater fluorescence quantum yields.

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Controlling and monitoring temperature at the single cell level has become pivotal in biology and medicine. Indeed, temperature influences many intracellular processes and is also involved as an activator in novel therapies. Aiming to assist such developments, several approaches have recently been proposed to probe cell temperature in vitro.

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Heat is of fundamental importance in many cellular processes such as cell metabolism, cell division and gene expression. (1-3) Accurate and noninvasive monitoring of temperature changes in individual cells could thus help clarify intricate cellular processes and develop new applications in biology and medicine. Here we report the use of green fluorescent proteins (GFP) as thermal nanoprobes suited for intracellular temperature mapping.

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The facile synthesis and photophysical properties of three nonhydrolyzable thioglycosylated porphyrinoids are reported. Starting from meso-perfluorophenylporphyrin, the nonhydrolyzable thioglycosylated porphyrin (PGlc₄), chlorin (CGlc₄), isobacteriochlorin (IGlc₄), and bacteriochlorin (BGlc₄) can be made in 2-3 steps. The ability to append a wide range of targeting agents onto the perfluorophenyl moieties, the chemical stability, and the ability to fine-tune the photophysical properties of the chromophores make this a suitable platform for development of biochemical tags, diagnostics, or as photodynamic therapeutic agents.

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A characteristic of cancer cells is the generation of lactate from glucose in spite of adequate oxygen for oxidative phosphorylation. This property - known as the "Warburg effect" or aerobic glycolysis - contrasts with anaerobic glycolysis, which is triggered in hypoxic normal cells. The Warburg effect is thought to provide a means for cancer cells to survive under conditions where oxygen is limited and to generate metabolites necessary for cell growth.

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While cancer is still an implacable disease, many cancers can be cured if they are diagnosed in an early stage. Recently, it was reported that the transformation from normal cells to cancer cells can change their mechanoelastic properties to become softer and more deformable. If some cancer cells are more deformable, then a progressive increase of the volume of softer cancer cells should be induced as an abrupt change in osmolarity is applied.

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A water-soluble tetra-S-glycosylated porphyrin (P-Glu(4)) is absorbed by MDA-MB-231 human breast cancer cells whereupon irradiation with visible light causes necrosis or apoptosis depending on the concentration of the porphyrin and the power of the light. With the same amount of light irradiation power (9.4 W m(-2)), at 10-20 microM concentrations necrosis is predominantly observed, while at <10 microM concentrations, apoptosis is the principal cause of cell death.

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A spectroscopic device for monitoring the temperature of aqueous solutions is presented. It uses a 950 nm light emission diode as light source and two photodiodes as detectors. Temperature is monitored following the thermally induced absorbance changes of the water-OH second overtone (approximately 960 nm).

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Background: Cathepsin B (CB) is a lysosomal cysteine proteinase synthesized as a zymogen of 39-47 kilodaltons (kD), which is subsequently converted into an active single- chain form of 33 kD (CB33) and, by additional processing, into the active 2-chain form containing a heavy chain of 27-29 kD (CB(27-29)) and a light chain of 4-6 kD. Increased or altered CB expression has been documented in a variety of tumor cells, but to the authors' knowledge only one study published to date has reported clinicopathologic significance for CB in transitional cell carcinoma (TCC) of the bladder.

Methods: In this work, CB expression was determined by Western blot analysis in TCC bladder tissue from 30 patients.

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