Detrimental impact of aqueous mobile phases on 18F-labelled radiopharmaceutical analysis radio-TLC.

The list of new positron-emission tomography (PET) tracers has rapidly grown in the past decade, following discoveries of new biological targets and therapeutic strategies, with several compounds garnering recent regulatory approval for clinical use. During the development of synthesis methods and production of new tracers for imaging, analytical methods for radio-high performance liquid chromatography (radio-HPLC) and radio-thin layer chromatography (radio-TLC) separations need to be developed to assess radiochemical compositions. Radio-TLC is often faster, simpler, and sometimes more accurate than radio-HPLC (as there is no underestimation of [F]fluoride when analyzing F-labeled radiopharmaceuticals).

Rapid Purification and Formulation of Radiopharmaceuticals via Thin-Layer Chromatography.

Before formulating radiopharmaceuticals for injection, it is necessary to remove various impurities via purification. Conventional synthesis methods involve relatively large quantities of reagents, requiring high-resolution and high-capacity chromatographic methods (e.g.

A rapid and systematic approach for the optimization of radio thin-layer chromatography resolution.

Radiopharmaceutical analysis is limited by conventional methods. Radio-HPLC may be inaccurate for some compounds (e.g.

Microliter-scale reaction arrays for economical high-throughput experimentation in radiochemistry.

The increasing number of positron-emission tomography (PET) tracers being developed to aid drug development and create new diagnostics has led to an increased need for radiosynthesis development and optimization. Current radiosynthesis instruments are designed to produce large-scale clinical batches and are often limited to performing a single synthesis before they must be decontaminated by waiting for radionuclide decay, followed by thorough cleaning or disposal of synthesizer components. Though with some radiosynthesizers it is possible to perform a few sequential radiosyntheses in a day, none allow for parallel radiosyntheses.

Optimization of Radiochemical Reactions using Droplet Arrays.

Current automated radiosynthesizers are designed to produce large clinical batches of radiopharmaceuticals. They are not well suited for reaction optimization or novel radiopharmaceutical development since each data point involves significant reagent consumption, and contamination of the apparatus requires time for radioactive decay before the next use. To address these limitations, a platform for performing arrays of miniature droplet-based reactions in parallel, each confined within a surface-tension trap on a patterned polytetrafluoroethylene-coated silicon "chip", was developed.

High-throughput radio-TLC analysis.

Introduction: Radio thin layer chromatography (radio-TLC) is commonly used to analyze purity of radiopharmaceuticals or to determine the reaction conversion when optimizing radiosynthesis processes. In applications where there are few radioactive species, radio-TLC is preferred over radio-high-performance liquid chromatography due to its simplicity and relatively quick analysis time. However, with current radio-TLC methods, it remains cumbersome to analyze a large number of samples during reaction optimization.

Electrochemical Flash Fluorination and Radiofluorination.

A new method for rapid late-stage fluorination using the cation pool technique is presented. Fluorination and no-carrier-added radiofluorination of methyl (phenylthio) acetate, methyl 2-(methylthio) acetate, and methyl 2-(ethylthio) acetate were performed. The carbocations formed through electrochemical oxidation were stabilized by using a divided electrochemical cell and 2,2,2-trifluoroethanol (TFE) as the solvent at -20 °C.

A novel multi-reaction microdroplet platform for rapid radiochemistry optimization.

During the development of novel tracers for positron emission tomography (PET), the optimization of the synthesis is hindered by practical limitations on the number of experiments that can be performed per day. Here we present a microliter droplet chip that contains multiple sites (4 or 16) to perform reactions simultaneously under the same or different conditions to accelerate radiosynthesis optimization.

Electrochemical Fluorination and Radiofluorination of Methyl(phenylthio)acetate Using Tetrabutylammonium Fluoride (TBAF).

Electrochemical fluorination of methyl(phenylthio)acetate was achieved using tetrabutylammonium fluoride (TBAF). Electrochemical fluorination was performed under potentiostatic anodic oxidation using an undivided cell in acetonitrile containing TBAF and triflic acid. The influence of several parameters including: oxidation potential, time, temperature, sonication, TBAF concentration and triflic acid concentration on fluorination efficiency were studied.

FRET-FLIM for Visualizing and Quantifying Protein Interactions in Live Plant Cells.

Proteins are the workhorses that control most biological processes in living cells. Although proteins can accomplish their functions independently, the vast majority of functions require proteins to interact with other proteins or biomacromolecules. Protein interactions can be investigated through biochemical assays such as co-immunoprecipitation (co-IP) or Western blot analysis, but such assays lack spatial information.

Antifreeze proteins govern the precipitation of trehalose in a freezing-avoiding insect at low temperature.

The remarkable adaptive strategies of insects to extreme environments are linked to the biochemical compounds in their body fluids. Trehalose, a versatile sugar molecule, can accumulate to high levels in freeze-tolerant and freeze-avoiding insects, functioning as a cryoprotectant and a supercooling agent. Antifreeze proteins (AFPs), known to protect organisms from freezing by lowering the freezing temperature and deferring the growth of ice, are present at high levels in some freeze-avoiding insects in winter, and yet, paradoxically are found in some freeze-tolerant insects.

[Pneumatosis cystoides intestinalis: a case report and review of the literature].

Pneumatosis cystoides intestinalis features the presence of subserum or submucous cysts with gas in the intestinal wall. Its prevalence is 0.03%, although it has increased in the past decades due to a greater use of colonoscopy in everyday medical practice.

Multiport logic operations triggered by protonation--a trisphenanthroline as a 3-input AND-NOR-OR circuit.

A linear bisphenanthroline (two binding sites) is set up to operate as a XNOR gate and a linear trisphenanthroline (three binding sites) as a molecular 3-input AND-NOR-OR logic circuit, both with H(+) as input signal and luminescence as output signal.