A fluorimeter was constructed which utilises solid state components. The novel
arrangement of these components meant that an inexpensive, sensitive, robust
and portable fluorimeter was feasible.
If the optical components ofthe instrument were selected for a specific assay, a
dedicated fluorimeter with comparable sensitivity to a research grade fluorimeter
resulted. The construction and evaluation of such a fluorimeter is described.
Nile Red is a hydrophobic phenoxazine fluorescent dye, which has an emission
in the long wavelength region of the spectrum (600 - 1000 nm).
Assays based on fluorescence measurements in this spectral region have the
advantage oflower background, reduced scattering and decreased
photodecompostion when compared with conventional fluorescence utilising
Nile Red is also a solvatochromic dye, which means it emission wavelength is
strongly dependant on its molecular environment.
The property is utilised here in the development of a novel assay for the protein
~-lactoglobulin. As the fluorescence properties of the Nile Red:Protein complex
differ form those ofthe unbound Nile Red molecule, the fluorescence intensity
can be related to concentration of the protein present. The feasibility and
development of such an assay is presented as one possible application for the
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.