What is Biophotonics?
Biophotonics is an emerging multidisciplinary research area, embracing all light-based
technologies applied to the life sciences and medicine. The expression itself is the
combination of the Greek syllables bios standing for life and phos standing for
light.
Photonics is the technical term for all methodologies and technologies utilizing
light over the whole spectrum from ultraviolet through the visible and the infrared to
the terahertz region, and its interaction with any matter (Figure 1.1).
Beyond this definition, biophotonics is a scientific discipline of remarkable societal
importance. For hundreds of years, researchers have utilized light-based systems to
explore the biological basics of life. After the invention of the light microscope dating
back to the seventeenth century and the systematic improvements introduced by Carl
Zeiss, Ernst Abbe and Otto Schott in Jena in the nineteenth century, it became an
essential tool in the life sciences and medicine and had a crucial influence on the
work of biologists of this time, such as Ernst Haeckel. Since then, its importance has
grown even stronger. Today, ultrahigh resolving microscopes enable us to observe
cellular structures smaller than 20 nm across and their functions, and thus to study
diseases right at their origin.
We also benefit greatly from photonic technologies in
medical practice – in fact both in diagnosis and in therapy of diseases. For example,
laser scalpels have become routine tools which reduce the expense of many surgeries,
sometimes even down to an ambulant intervention (keyhole surgery). Due to novel
photonic technologies such as fluorescence endoscopy and photodynamic therapy
(PDT), some types of cancer can be recognized much earlier and treated more gently
than several years before. In ophthalmology, optical coherence tomography (OCT)
has become the gold standard for detecting morphological changes in the eye by
adding the third dimension, helping to obtain high-resolution 3D images of the
retina and diagnose prevalent diseases such as glaucoma and macular degeneration.
Visions Connected with Biophotonics Research
The controlled use of light has already revolutionized life in many respects
(Figure 1.2). There is high hope that light as a tool will provide further breakthroughs
in the life sciences and medicine, and also in closely related topics and subjects such
as nutrition, the environment and well-being in general. A current example from the
field of medicine is a novel approach for the early recognition of Alzheimers disease,
which so far is considered incurable. In the next few years, fluorescence imaging
could provide reliable early recognition and help to verify novel therapeutic
approaches which aim at an early intervention in the future [3]. Basically, light
allows us to explore cellular structures and functions rapidly and with utmost
sensitivity and precision. At the same time, light allows us to manipulate tissues
and cellular structures without damaging them. These features make light a unique
tool for the whole range of modern medicine:
1) Understanding diseases on a molecular level: Light helps to explore fundamental
life processes on a cellular and molecular level, and thus to develop novel,
targeted therapies.
2) Early recognition of diseases: Light allows us to recognize changes on the cellular
scale as early signs of diseases, even long before manifest symptoms occur. The
earlier is the diagnosis, the better are the chances of healing.
3) Targeted treatment of diseases: Light measures and cures in a careful manner,
paving the way towards minimally invasive medicine.
4) Preventing diseases: Light can measure a multitude of health-relevant parameters, including endogenous parameters such as genetic dispositions and
physiological conditions, and also exogenous parameters such as pathogens in
air, water, and food. This helps to monitor the health state of individuals and
possible harmful influences, which is an important prerequisite to prevent
diseases.
Thus the term biophotonics covers a wide spectrum of biomedical questions
from understanding life processes to prevention, early recognition, and therapy of
diseases. Attention should be paid to an alternative use of the term as a complement
to the term biomedical optics. In that context, the field of biophotonics only covers
applications of photonics in the life sciences and fundamental biomedical research
such as the investigation of cellular processes, whereas the field of biomedical optics
covers the clinical applications of light in diagnostics and therapy. This distinction
seems to have evolved historically, as the term photonics was only coined about 50
years ago, when light-based technologies were already well established in medicine.
In this book, the term biophotonics is used for both mentioned areas. Furthermore,
it reaches into the fields of environmental, food and pharmaceutical analysis and thus
even applies to the fields of process control and security applications. The authors
consider this definition more conclusive, more purposeful and more forwardlooking, as it provides a holistic perspective. This approach advances a likewise
holistic, modern health care, and particularly the groundbreaking paradigm change
from the treatment of diseases towards health maintenance. Moreover, the close
linking of diagnosis, therapy, preventive and follow-up care paves the way towards
