Chemistry Reference
In-Depth Information
[
]
2
2
ΦΦ
x
=
AA
/
ηη
(1.5)
STXST
x
ST
where the subscripts ST and X denote standard and samples respectively, Φ is the fluorescence quantum yield,
A
the
integrated area of emission band, and η the refractive index of the solvent. Φ can be used to assess the brightness of the fluo-
rophore, which is the product of the quantum yield and the extinction coefficient of the fluorophore.
The advent of traditional fluorescence microscopy has initiated an important era in the study of living cells. Since then,
many more creative engineering and sophisticated designs of microscopes have emerged, providing new and better optical
imaging techniques for both academic and clinical studies. Simultaneously, it has also given rise to a new research area in
the development of biological fluorophores, such as fluorescent proteins and GFP, which have provided insight into cellular
structures and functions. Fluorophores improve or define image contrast, which is the difference between the highest and
(a)
Digital camera systems
Arc lamp
Aperture
diaphragm
Field diaphragm
Observation tubes
Filter
Filter
Objective
focal planes
(b)
Extended light source
*
*
* * * * * *
Thick sample
Collection light path
Illumination light path
FIgure 1.20
(a) A conventional fluorescence microscope and (b) the light path in a fluorescence microscope.
