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Biomedical subjects

Darcy Lichlyter

Publications and source records attributed to Darcy Lichlyter.

3 recordsLinked to original sources

A ratiometric fluorescent viscosity sensor.

The development of a dual probe that provides ratiometric measurements of fluid viscosity is described. The design is based on coupling of a primary fluorophore with viscosity-independent fluorescence emission (blue unit) with a secondary fluorophore that exhibits viscosity-sensitive fluorescent emission quantum yield (red unit). Excitation of the secondary fluorophore can be achieved via Resonance Energy Transfer. The ratio of the fluorescence emission of these fluorophores provides an accurate, ratiometric measurement of solvent viscosity.

Acrylates↗

Viability of a FRET dual binding technique to detect calpastatin.

We have been investigating a fluorescence dual binding biosensor to detect calpastatin. Calpastatin is a protein found in meat and it is a regulator of meat tenderness. The ability to accurately predict the calpastatin concentration of beef with a biological sensor at the time of grading would lead to a more accurate assessment of the overall palatability of beef when it reaches the consumer. Meat can then be labeled as tender or tough, which would greatly enhance meat processors' ability to grade meat, allowing them to recover lost revenue. The biosensor technique utilized the chemical transduction principle of fluorescence resonance energy transfer (FRET). FRET requires the use of two fluorophores, termed a donor and acceptor. In this study, the donor fluorophore was conjugated to the protein, mu-calpain, while the acceptor fluorophore was conjugated to a monoclonal antibody. The results showed that in the presence of calpastatin, the labeled mu-calpain and antibody would bind to calpastatin, reducing the distance between the two proteins and eliciting a measurable change in fluorescence. The FRET dual binding technique was tested in heated and unheated meat extract, and a limit of detection for calpastatin was 120 ng/ml in diluted heated meat extract with no significant response in the unheated meat extract. Stable response times were achieved within 5 min. The proof-of-principle of utilizing a FRET dual binding technique to detect calpastatin in heated meat extract has been established.

Calcium-Binding Proteins↗

Hydrophilic molecular rotor derivatives-synthesis and characterization.

Recent research shows high potential for some p-N,N-dialkylaminobenzylidenecyanoacetates, part of a group known as fluorescent molecular rotors, to serve as fluorescent, non-mechanical viscosity sensors. Of particular interest are molecules compatible with aqueous environments. In this study, we present the synthesis and physical characterization of derivatives from 9-(2-carboxy-2-cyanovinyl)-julolidine and related molecules. All compounds show a power-law relationship of fluorescence emission with the viscosity of the solvent, different mixtures of ethylene glycol and glycerol to modulate viscosity. Compounds with high water solubility exhibit the same behavior in aqueous solutions of dextran, where the dextran concentration was varied to modulate viscosity. In addition, some compounds have been found to have low sensitivity towards changes in the pH in the physiological range. The compounds presented show promise to be used in biofluids, such as blood plasma or lymphatic fluid, to rapidly and non-mechanically determine viscosity.

Acetates↗