Aquaphotomics is a new term, introduced to describe rapid and comprehensive analysis of water-light interaction at each frequency of the electromagnetic spectrum as a potential source of information for better understanding of the biological world through the water and spectroscopy. This approach to spectroscopy opens a new area in biological sciences and engineering. It describes a new way for exploring biological systems through a non- destructive monitoring of their interaction with VIS-NIR light.

Multivariate spectral analysis reveals that changes with the water matrix under perturbation reflect, like a mirror, the rest of the molecules surrounded by water. As a result, characteristic water absorbance patterns are used to measure very small concentrations of solutes and for disease diagnosis.

What does Aquaphotomics mean?
aqua: water
photo- : light, radiant energy
- mics: all about something (Greek)

In the last decades life science has taken systematic approach to revealing the molecular picture of living organisms’ functioning. It is clearly understood that only by combining the previously segmented knowledge and bringing it to a systematic and interconnected database level we can come closer to revealing the intrinsic inter-dependable pathways that represent life. Both genomics and proteomics have revolutionized life science. Nevertheless creating databases and further using them for metabolic processes research requires isolation of individual elements (genes, proteins) one at a time, making such analyses extremely time consuming and laborious. More over it requires destruction of the analyzed object and thus provides a single time-point picture of the processes. Considering the speed, plasticity and multifactor-dependence of metabolic processes it is clear that such static one-at-a-time approach needs to be replaced with more dynamic and real-time methods.
This idea has already been proposed by metabolomics (the science of all metabolites in a cell/organism at a given moment) and is further expanded by the newest omics – aquaphotomics (the science of water interaction with solvents visualized by Vis-NIR light absorbance pattern). Even though these two methods are taking completely different approaches, they try to solve the same problem – to provide systematic, at a glance view of the processes with time-dependent information of their interconnections as well as a speed and possibility to study the same object continually (that is, to study it non-destructively).

How is Aquaphotomics defined?

Water Matrix Coordinates (WAMACS): Water matrix is defined by the absorbencies of all water species of a sample in a 3D space. Multivariate analysis of such water matrix of a number of similar samples under various perturbations could provide extended knowledge (aquaphotome) about the respective biological sample. The term “WAter MAtrix CoordinateS” (WAMACS) is introduced to capture and present the information about the influence of different perturbations on the water absorbance in VIS-NIR range for various biological samples.

Water Absorbance Pattern (WAP): As water is very easily influenced by various factors, it has been proposed to use the spectral changes of studied aqueous and biological systems, under various perturbations, to learn more about the water matrix and the rest of molecules that are surrounded by water through the changes of water absorbance patterns, WAP, when following respective perturbation.

Aquaphotome: the entire complement of water molecules and light interactions in the presence of other bio molecules, i.e. comprehensive spectral assignment of all existing water absorbance bands. The water absorbance bands of respective systems (WAMACS) found under various perturbations will define the respective aquaphotome for each particular system.

Extended Water Mirror Approach (EWMA): It is assumed that the rest of the elements in a complex system are “reflected” on molecular level by the water. Its composition and structure, described by WAMACS give information for the rest of the elements in the system, as well as, for the water in the same manner as the reflection of a water mirror gives all the visible details of the surroundings.

As water is the most abundant element in all living organisms, the approach of Aquaphotomics provide us with an unique opportunity to monitor the metabolism and molecular changes non-invasively and real time. Here are just a few of the successful applications in life sciences and medicine.

Aquaphotomics: in bio monitoring and diagnosis

Mastitis disease

“Altered milk components trace signals influence the bonding structure of water measured by NIRS all at once and provide rapid and accurate mastitis diagnosis”
Tsenkova R., Atanassova S., Kawano S., Toyoda K., ”Somatic cell count determination in cow milk by near infrared spectroscopy: A new diagnostic tool”, J Animal Sci pp.2550-2557, 2001.

Prion disease

“…consecutive exposure of hydrogen bond network, in the body of mouse, to NIR light allowed successful diagnosis of fatal prion disease”
Tsenkova R., Iordanova I., Toyoda K., and Brown D., “Prion protein fate governed by metal binding” BBRC pp.1005-1012, 2004.

Soybean Mosaic disease

“ Monitoring of Second Overtone of Water Absorbance Bands Reveals Hypersensitive Response from Virus Infected Plants”
Jinendra B., Tamaki K., Kuroki S., Vassileva M., Yoshida S., Tsenkova R. “Near infrared spectroscopy and aquaphotomics: Novel approach for rapid in vivo diagnosis of virus infected soybean”

Virus diagnosis - HIV

“Regression vector coefficients reveals variations in water structures related to functionality of HIV”
Sakudo A., Tsenkova R., Onozuka D., Morita K., Li S, Warachit J., Iwabu I., Li G., Onodera T., Ikuta K
“A novel diagnostic method for human immunodeficiency virus type-1 in plasma by near-infrared spectroscopy” Microbiol Immunol, 49 (7), pp. 695-701, 2005.

Panda ovulation detection

“NIRS with Aquaphotomics show the differences between normal and abnormal estrus, or pregnancy and pseudopregnancy.”
Kinoshita K., Morita H., Miyazaki M., Hama N., Kanemitsu H., Kawakami H., Wang P., Ishikawa O., Kusunoki H., Tsenkova R. “Near infrared spectroscopy of urine proves useful for estimating ovulation in Giant Panda (Ailuropoda melanoleuca)” Analytical Methods, 2010.

Cow Estrus detection
"Detection of Estrus in Dairy Cows by Means of Near Infrared Spectroscopy and Aquaphotomics"
Takemura G.,Bazar G., Ikuta K., Yamaguchi E., Tsenkova R.
Poster presentation at The 17th International Diffuse Reflectance Conference, Chambersburg, 2014.

Detection of cow estrus by quantification of progesterone (hormone) using milk, urine and serum.

Freshness of raw milk
"Freshness Assessment of Raw milk using Near Infrared Spectroscopy"
Osawa M., Ikuta K., Kubota Y., Tsenkova R.
Poster presentation at The 73rd Japanese Society of Agricultural Machinery and Food Engineers Conference, Okinawa, 2014.

Detection of minute concentration of solutes represents a great analytical and particularly spectroscopic challenge. The specific signal from the solute drops sharply with decreasing concentration. Here Aquaphotomics offers a real break through, as it allows measuring very low concentrations of solutes by following the changes in the absorbance pattern of the solvent – water. Here are a few examples.

Aquaphotomics: in micro particle analysis

Micro suspension in water

“Better prediction of polystyrene mesoscopic particle concentration is obtained by multivariate analysis based on water absorbance bands than univariate method based on polystyrene absorbance band at 1680nm”
Iso E, Tsenkova R. “A NIRS Investigation into the Perturbation of Water Spectrum in an Aqueous Suspension of Mesoscopic Scale Polystyrene Spheres” Asia Near Infrared Conference, Tsukuba 2008

Heavy metal in water

“Low concentration measurements of Cd, Mg, Mn, Zn in water solution possible because of the interaction with water “seen” by the NIR light at various water absorbance bands.
Sakudo A., Tsenkova R., Tei K., Onozuka T., Ikuta K., Yoshimura E. and Onodera T. “Comparison of Vibration Mode of Metals in HNO3 by Partial Least Squares Regression” Bioscience Biotechnology and Biochemistry, 2006.
“Non-organic Cadmium detection by Aquaphotomics” Vassileva M, Putra A, Gowen A and Tsenkova R, poster at International Diffuse Reflectance Conference, Chambersburg 2010

Bacterial identification

"Near Infrared Spectroscopy (NIRS) and Aquaphotomics for Understanding Probiotic Lactic Acid Bacteria (LAB)"
Koshiba H., Slavchev A., Kovacs Z., Nagai A., Tsenkova R.
Poster presentation at The 17th International Diffuse Reflectance Conference, Chambersburg, 2014.

Bacterial detection

“Detection of bacteria in water by NIRS and aquaphotomics” Nakai K, Nakakimura Y, Styanchev T, Vassileva M, and Tsenkova R, poster at International Diffuse Reflectance Conference, Chambersburg 2010
“Detection of Staphylococcus aureus and Escherichia coli by Near-Infrared Spectroscopy” Nakakimura Y, Nakai K, Styanchev T, Vassileva M, and Tsenkova R, poster at International Diffuse Reflectance Conference, Chambersburg 2010

Quantification of Available Chlorine Concentration (ACC)
"Quatification of Available Chlorine Concentration by Near Infrared Spectroscopy"
Itakura Y., Katayose M., Tsenkova R. Poster presentation at The 73rd Japanese Society of Agricultural Machinery and Food Engineers Conference, Okinawa, 2014.