Fiber-Optic Raman Probes for Biomedical and Pharmaceutical Applications - Emerging Raman Applications and Techniques in Biomedical and Pharmaceutical Fields - page 25

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Fiber-Optic Raman Probes for Biomedical
and Pharmaceutical Applications
Hidetoshi Sato, Hideyuki Shinzawa, and Yuichi Komachi
Abstract This chapter reviews the development of optical fiber probe Raman sys-
tems and their applications in life science and pharmaceutical studies. Especially, it
is focused on miniaturized Raman probes which open new era in the spectroscopy
of the life forms. The chapter also introduces the important optical properties of
conventional optical fibers to use for Raman probes, as well as new types of optical
fiber and devices, such as hollow optical fibers and photonic crystal fibers.
2.1 Introduction
The recent evolution of Raman spectroscopy makes its practical clinical ap-
plication more realistic. Especially important has been development of high-
performance devices and spectral analysis methods, especially chemometrics.
Many researchers have reported that they have succeeded in identifying strains
and species of bacteria, in monitoring cell cycles and proliferation, and the
diagnosis of cancerous tissues using in vitro Raman spectroscopy and chemo-
metrics analysis [1-13]. Drug-resistant strains of bacteria have only small dif-
ferences in their genes compared to wild types, but Raman spectroscopy has
been able to detect the differences [1, 5, 7, 8]. The remarkable results of re-
search in this field encourages us to believe that it may be possible to use
Raman spectroscopy to diagnose cancers and other diseases that are induced
by small gene alterations. If it is possible to obtain high-quality Raman spec-
tra of the diseased tissue in vivo, it may be possible to diagnose the disease
in internal organs. A narrow fiber-optic Raman probe is an attractive tool for
this purpose [14-41]. It allows us to reach a lesion in a human subject and
obtain information about the diseased tissues directly.
By inserting the Raman probe into the channel of various endoscopes,
we can access the inside of the stomach, the large and small intestines, the
bronchus, and portions of the pancreatic and bile ducts. If it is used with a
laparoscope, the accessible areas expand to the liver and the outer walls of
the digestive organs. If the probe is narrow enough to insert in hypodermic