INTRODUCTION:

Biophotonics is the study of the interaction of light with biological material, where “light” includes all forms of radiant energy whose quantum unit is the photon. It is focused on translating discoveries in the sciences around lasers, light and imaging into useful medical tools. In this regard, medical imaging and in vitro diagnostics are just two of the many applications of biophotonics that already has had an enormous positive impact on our lives. Besides advancing the frontiers of medical technology, biophotonics is also being applied to non-medical applications. Light and other forms of radiant energy can be used to image, analyze and manipulate living tissue at cellular and molecular level, in a non-invasive or minimally invasive manner.

Photonics is a very active area where new developments occur on a weekly basis, while established tools are adapted to fulfill the needs of other disciplines like genomics and proteomics.

Biophotonics emerged at the interface of photonics and biology as a very straight forward and efficient approach to observe and manipulate living systems.

History:

In 1923, Alexander Gurwitsch discovered an ‘ultra weak’ photon emission from living systems (onions, yeast). He suggested that there were connections between photon emission and cell division rate. He called this photonemission as ‘mitogenetic radiation’. In 1950, Russian scientists rediscovered an ‘ultraweak photon emission’ from living organisms. Italian nuclear physicists discovered ‘bioluminescence’ of seedlings. A Russian biophysicist and an American chemist enunciated the first theory of ultra weak photon emission (UWPE) from biological systems, the so called ‘Imperfection Theory’. UWPE is supposed to be an expression of the deviation from equilibrium, some kind of distortion of metabolic processes. Scientific groups in Australia (Quickenden), Germany (Fritz-Albert Popp), Japan (Inaba), and Poland (Slawinski) showed evidence of UWPE from biological systems by use of modern single-photon counting systems.

From 1972 to 1980, many scientific workers experimentally evaluated all the essential physical properties of biophotons viz,

1. The intensity ranges from a few upto some hundreds of photons/(s cm²)

2. The spectral distribution follows the time average a f = const-rule

3. The modes are strongly coupled

4. The delayed luminescence continuously approaching the bio photon emission follows a hyperbolic rather than an exponential relaxation function

5. The biophotons originate from an almost fully coherent field

6. Cells are able to establish cavity resonators which contribute to bio photon regulation

7. The essential source of non-equilibrium bio photon emission is the DNA

The group for the first time found intercellular communication by means of biophotons. Later this was confirmed by Albrecht-Buhler (Bacteria), Popp and Chang (dinoflagellates), Galle (daphnia), Shen (blood) and Vogel (bacteria).

Biophotonics – Visions for Better Health Care:

Biophotonics deals with the interaction between light and biological systems. The word itself is a combination of the Greek syllables bios standing for life and phos standing for light. Photonics is the technical term for all procedures, technologies, devices, etc. utilizing light in interaction with any matter. Photonics encompasses the entire physical, chemical and biological laws of nature, together with technologies for the generation, amplification, control, manipulation, propagation, measurement, harnessing and any other type of utilization of light.

Photonics emphasizes the huge importance of light for our modern human society. Photonics is a key technology for solving momentous problems in the domains of health care, food production and technology, environmental protection, transportation, mobility, etc. It helps in the development of communication and production technology, biotechnology and nanotechnology (Prasad and Paras, 2003).

The optical phenomena used to gain all this information include the interactions of electromagnetic radiation with living organisms or organic material, such as absorption, emission, reflection, scattering, etc. Other areas of Biophotonics use light as a miniaturized tool, e.g., optical tweezers or a laser scalpel (Susanne Liedtke et al., 2007).

Biophotonics as a driving force of innovation:

Biophotonics is an invented word integrating biotechnology, medical technology, pharmacy and food production with optical technologies, i.e. photonics. It aims to use light (photons are energy-rich light packages) in order to elucidate biological processes and shed light on the processes of life. Light can be used to present microscopically small processes (such as in cells) extremely fast and without the need to touch, hence it doesn’t disturb or otherwise influence the process. Current diagnostic methods provide the results hours or even days after the examination; in addition they are a lot more inaccurate than methods that rely on light. Only light is very versatile: it has spectral characteristics, wavelength, phase, bandwidth and intensity, pulse duration and can be focused (Popp et al., 2002)

Biophotonics - Light for Life:

Biophotonics research focuses on the use of the unique characteristics of light in the areas of biotechnology, medical technology, pharmaceutical technology and food production. Light enables us to watch microscopic processes, for example within living cells, in an extremely brief time span and a non-invasive form, i.e. without disturbing or influencing the process. Traditional diagnoses often take several weeks to provide results. They are considerably less precise than light as only light possesses a large number of parameters e.g. its spectral characteristics such as wave length, phase, band width and intensity, pulse duration and ability to be focussed.

Biophotons and Communication between DNA:

DNA possesses an information density that is 1.E⁹higher than any technical solution known today. The typical cellular volume is 1.E^-9 cm3. It houses a 2m long macromolecule in which 100.E⁹ base-pairs are wrapped. Stretched out along a line, the human DNA would cover a distance of 10.E¹² m (the diameter of our solar system!). This exorbitant information density leads to a phenomena known in physics as Bose-Einstein-Condensate i.e., photons are trapped (much like in a cryotrap), condense and “freeze” in time (a totally different state of matter/energy).

The stored light accounts for the elemental stability of the DNA-molecule. The Bose-Einstein-Condensate enables a coherent cell-biological state; i.e. Photons of same frequency and phase align to each other and become coherent; thereby, the range of interaction increases from the microscopic to include macroscopic entities (cells, organs, and entire organisms). 75% of biophotonic activity originates from the DNA. Purified DNA is biophotonically inactive (Maricela et al., 2006).

Inside the cell:

Many researchers are working towards identifying small and minute structures and finest cellular interactions with light-aided high tech using Electron transfer microscopy, laser light traps, laser micromanipulations, spectroscopy, optical probes and markers. With this method, the surgeon would be able to differentiate cancer cells from healthy cells during the operation, and so he would be certain about which tissue to remove and which to keep. It would even be possible to identify diseased cells and destroy them. Biological probes would help diagnose diseases much faster and genetic maps could be generated.

Tissue investigations:

Activities in the biophotonics field concern the investigation of biological tissues i. e. the monitoring of active components in plants and especially the localization of pharmaceutical relevant substances in tissues. Furthermore, the mode of action of drugs against infectious diseases (e. g. antibiotics against malaria or gyrase inhibitors) is investigated on a molecular level by means of a combination of vibrational spectroscopy and quantum chemical calculations. These studies are important for the development of new and more effective active agents.

Biomimetic biophotonics;

Biomimetic biophotonics is the development of novel and advanced photonic devices inspired from nature, which can be utilized for biosensing, bioimaging, or biomanipulation. It employs not only conventional materials and fabrication methods but also engineering polymers and non-conventional 3D micro/nanofabrication methods. Biophotonic sensing/imaging cover the integration of the Micro/Nano Electro-Mechanical systems enabled biophotonic systems. The advanced measurement, detection, and imaging tools will give biologists more accurate and convenient metrological techniques with high efficiency. Biophotonic therapy also contains the implementation of next generation therapeutic systems with biophotonic sensing/imaging functions.

Nano-biophotonics:

Nano-biophotonics consists of four broad areas such as molecular bioimaging, nano-biosensors, multiplexed bioassays and nanotechnology-based medical practices for diagnosis and therapy. Success in these areas is challenged by the underlying complexity of biological systems. Major levels of complexity and associated technical barriers appear at all levels of biology including the molecular, cellular, and tissue and organism levels.

Multi-scalable Biophotonocs

Molecular level:

A multimodality molecular imaging technique integrating atomic force, polarized Raman, and fluorescence lifetime microscopies, together with 2D autocorrelation image analysis is applied to the study of a mesoscopic heterostucture of nanoscale materials. This approach enables simultaneous measurement of fluorescence emission and Raman shifts from a quantum dot (QD) - single-wall carbon nanotube (SWCNT) complex. Nanoscale physical and optoelectronic characteristics are observed including local QD concentrations, orientation-dependent polarization anisotropy of the SWCNT Raman intensities, and charge transfer from photo-excited QDs to covalently conjugated SWCNTs. Measurement approach bridges the properties observed in bulk and single nanomaterial studies. This methodology provides fundamental understanding of the charge and energy transfer between nanoscale materials in an assembly.

Areas of related measurement science and techniques include

Time-correlated confocal nano-spectroscopic microscopy of single and clustered nanoprobes

· Integrated microscopy of photo-excited nanoparticles and related processes

· Optical tweezers and single molecule spectroscopy and microscopy

Cellular level:

With current concerns of antibiotic-resistant bacteria and biodefense, it has become important to rapidly identify infectious bacteria. Traditional technologies involving isolation and amplification of the pathogenic bacteria are time-consuming. It is a rapid and simple method that combines with in vivo biotinylation of engineered host-specific bacteriophage and conjugation of the phage to streptavidin-coated quantum dots. The method provides specific detection of as few as 10 bacterial cells per milliliter in experimental samples, with a 100-fold amplification of the signal over background in 1 hour.

Tissue and organism level:

Enumeration of bacterial colonies in an agar plate is simple in concept, but automated colony counting is difficult due to variations in colony color, size, shape, contrast, and density, as well as colony overlaps. Furthermore, in applications where high throughput is essential, it is critical to employ a fast and user-friendly automated technique that does not compromise counting accuracy. While commercial products exist that can count bacterial colonies, they can be cost-prohibitive for small laboratories. Integrated Colony Enumerator was designed to count dark colonies from multiple regions of interests on an agar plate.

Imaging in Biophotonics:

1. In vivo Bioluminescence imaging:

Research is being conducted, inter alia, on microscopic procedures, methods of optical spectroscopy, screening techniques in cellular systems as well as probe and marker technologies. Specific objectives of the research work are the early recognition of tumours, studies of a multi-purpose biochip reader for gene analysis, the detection of bacterial contamination and a rapid and reliable pollen forecast (Gross and Piwnica-Worms, 2005).

2. Biophotonic Imaging:

The pharmaceutical industry currently invests significant time, money and animals lives into testing the efficacy and safety of its drugs and compounds. The major bottleneck in drug development is the requirement of preclinical animal studies. This essential in vivo experiment is not only laborious and expensive, but necessitates the sacrifice of large numbers of animals, usually rodents, in experimental procedures that are becoming increasingly more controversial. Being able to reduce the number of animals used in these studies without reducing the quality of the data obtained would be extremely advantageous, especially from an animal welfare perspective (Contag, 2002)

Using Biophotonic Imaging, it is possible to develop predictive assays with the capacity to replace conventional animal studies that use death as an endpoint. If an animal has a disease that is rapidly expanding in an uncontrolled manner, it is likely that the disease will eventually lead to the death of the animal. Thus, labeling the disease with a Biophotonic Imaging marker will allow the changing photon signal to be monitored from outside of the animal so that an accurate prediction of the speed and magnitude of the disease expansion or regression can be recorded and graphed. The data obtained can then be used to estimate whether an animal will survive or die (Lyons, 2005).

Applications of Biophotonics:

Application of Biophotonics will lead to better health by which cancer and other infectious diseases can be defeated very effectively. Thus the quality of life will dramatically improve and the cost of health care will be considerably reduced. Areas in which Biophotonics is already being used successfully include pathology, oncology, dermatology, cardiology, urology, ophthalmology, gastroenterology, dentistry, etc. As a consequence, Biophotonics will become as important as other leading technologies, such as nanotechnology, genomics and proteomics (Faupel et al., 2005).

Optical technologies are making a major contribution to considerably improved early recognition. Researchers are currently working on an even better optical diagnosis of, for example, intestinal carcinoma or the visualization of lumps and sclerosis.

Biophotonics can be used to study biological materials or materials with properties similar to biological material, i.e., scattering material, on a microscopic or macroscopic scale. On the microscopic scale, common applications include microscopy and optical coherence tomography. On the macroscopic scale, the light is diffuse and applications commonly deal with diffuse optical imaging and tomography (DOI and DOT). In microscopy, the development and refinement of the confocal microscope, the fluorescence microscope, and the total internal reflection fluorescence microscope all belong to the field of biophotonics. The specimens that are imaged with microscopic techniques can also be manipulated by optical tweezers and laser micro-scalpels, which are further applications in the field of biophotonics. (Brownstein et al., 2007)

DOT is a method used to reconstruct an internal anomaly inside a scattering material. The method is non invasive and only requires the data collected at the boundaries. The typical procedure involves scanning a sample with a light source while collecting light that exits the boundaries. The collected light is then matched with a model, for example, the diffusion model, giving an optimization problem.

CONCLUSIONS:

Biophotonics is used in biology to probe for molecular mechanisms, function and structure. It is used in medicine to study tissue and blood at the macro and microorganism level to detect, diagnose and treat diseases in a way that are non-invasive. It is not a science as an end in itself. In fact it opens undreamed-of possibilities for fundamental research, the pharmaceutical and food industries, biotechnology, medicine, etc. The ultimate goal of Biophotonics is to unravel life processes within cells, cell colonies, tissues, or even whole organs. Biophotonics seeks to provide a comprehensive multidimensional understanding of the various processes occurring in an organism. Therefore, Biophotonics combines all optical methods to investigate the structural, functional, mechanical, biological and chemical properties of biological materials and systems.

REFERENCES:

1. Brownstein, Michael, Hoffman, Robert A, Levenson, Richard, Milner, Thomas E, Dowell, M.L., Williams, P.A., White, G.S., Gaigalas, A.K., Hwang, J.C., 2007. Biophotonic Tools in Cell and Tissue Diagnostics. J. Res. Natl. Inst. Stand. Technol, 112 (3): 139–152.

2. Contag P.R., 2002. Whole-animal cellular and molecular imaging to accelerate drug development. Drug Discovery Today, 555-562.

3. Faupel, M., Brandenburg, A., Smigielski, P. and Fontaine, J. (Eds), 2005. Biophotonics for Life Sciences and Medicine. FontisMedia, Lausanne / Formatis, Basel, in press.

4. Gross S and Piwnica-Worms D., 2005. Spying on cancer: Molecular imaging in vivo with genetically encoded reporters. Cancer Cell, 7 (1): 5-15.

5. Lyons S. K., 2005. Advances in imaging mouse tumour models in vivo. J. Pathol, 205 (2): 194-205

6. Marriott, Gerard (Ed), 2003. Biophotonics. Academic Press, San Diego, 1- 590.

7. Maricela YIP & Pierre MADL, 2006. Biophotonics PART 1: The Light of Life Biosemiotics salsburg, 1-35.

8. Popp F.A, Chang J.J, Herzog A, Yan Z and Yan Y., 2002. Evidence of Non-Classical (Squeezed) Light in Biological Systems. Phys.Lett. 293: 98-102.

9. Prasad and Paras N, 2003. Introduction to biophotonics. Wiley-Interscience, Hoboken, New Jersey, 1-616. Susanne Liedtke, Michael Schmitt, Marion Strehle and Jürgen Popp, 2006. Biophotonics –Visions for Better Health Care. Wiley-VCH Verlag GmbH &

10. Co. KGaA, Weinheim, 1-30.

Received on 29.08.2013 Accepted on 01.09.2013

Research J. Engineering and Tech. 4(4): Oct.-Dec., 2013 page 208-212