Akinori Taketani

Discrimination of fish egg quality and viability by Raman spectroscopy

Egg or embryo quality is typically assessed by viewing the egg morphology and by observing the cleavage rate of the embryo. Assessment of egg or embryo quality based on bio-molecular information might lead to improved outcomes for aquaculture or in vitro fertilization (IVF) treatments. To assess the egg quality, we performed Raman spectroscopy on fish eggs from the Japanese medaka (Oryzias latipes). Good classification results from the yolk were obtained using principal component analysis (PCA) and linear discrimination analysis (LDA). The results show that the supply of oil energy starts immediately after fertilization and embryogenesis is initiated. The presence or absence of fertilization can be evaluated by fatty acid Raman bands with 95.7% accuracy. The Raman results show that the key factors that indicate the viability of fish eggs are amino acid production and carotenoid pigment deposition. The LDA algorithm based on the Raman bands of these substances indicates whether the development is normal or abnormal with 80.3% accuracy. These results show that Raman spectroscopy can be a powerful tool for non-invasive assessment and real time monitoring of fish egg quality and viability.

Raman endoscopy for real time monitoring of anticancer drug treatment in colorectal tumors of live model mice

The aim of the present study is to evaluate the capability of a miniaturized Raman endoscope (mRE) system to monitor the advancement of colorectal tumors in live model mice. The endoscope is narrow enough to observe the inside of the mouse colon under anesthesia. The mRE system allows to observe the tissues and to apply a miniaturized Raman probe for the measurement at any targeted point within the colon. Raman spectroscopy allows obtaining information about molecular composition without damaging the tissue (i.e., noninvasively). Continuous monitoring of the same tumor is carried out to study molecular alterations along with its advancement. The Raman spectra measured before and after the anticancer drug (5-FU) treatment indicated spectral changes in the tumor tissue. It suggests that the tumor is not cured but supposedly transformed to another tumor type after the treatment.

Observation of rat’s colon polyps in real time by mini-endoscopy and raman spectroscopy

Colorectal adenoma (CA) is a disease caused by various factors (such as genetic factors or environmental exposures). The appearance of colon polyp (CP) within colorectal might indicate the hint of CA development. Ball-lens hollow fiber Raman probe (BHRP) may has a high capability for detection of CA in living experimental animal and have already tested to rat’s CP in this study, which was designed to collaborate between BHRP with mini-endoscopy to observe the biochemical alteration within normal colon tissue and rat’s colon polyps in real time. BHRP and mini-endoscopy can distinguish the differences in their finger print spectra and make pictures the control and CP in the real time. At the first step, the real situation of normal colon and Rat’s CP were washed by saline and observed with mini-endoscopy. BHRP was introduced to Dextran sodium sulphate (DSS)-induced Rats CP to detect some of biochemical alteration. The main purpose of this study was to introduce mini-endoscopy to guide the BHRP for diagnosing of CP in real time and to compare it with spectra of normal colon (control group) in living rat. As the result, BHRP can provide the differences in band of control and CP group, which can inform that the biochemical of normal and CP has changed. As a major parameter to distinct normal and CP tissue were phosphatidylinositol, phosphodiester group, lipid, and collagen. Mini endoscopy and BHRP is very sensitive devices for diagnosing of CP in real time.

Measurement of the human esophageal cancer in an early stage with Raman spectroscopy

The esophageal cancer has a tendency to transfer to another part of the body and the surgical operation itself sometimes gives high risk in vital function because many delicate organs exist near the esophagus. So the esophageal cancer is a disease with a high mortality. So, in order to lead a higher survival rate five years after the cancer’s treatment, the investigation of the diagnosis methods or techniques of the cancer in an early stage and support the therapy are required. In this study, we performed the ex vivo experiments to obtain the Raman spectra from normal and early-stage tumor (stage-0) human esophageal sample by using Raman spectroscopy. The Raman spectra are collected by the homemade Raman spectrometer with the wavelength of 785 nm and Raman probe with 600-um-diameter. The principal component analysis (PCA) is performed after collection of spectra to recognize which materials changed in normal part and cancerous pert. After that, the linear discriminant analysis (LDA) is performed to predict the tissue type. The result of PCA indicates that the tumor tissue is associated with a decrease in tryptophan concentration. Furthermore, we can predict the tissue type with 80% accuracy by LDA which model is made by tryptophan bands.

Application of ball-lens hollow fiber Raman probe for studying anorectal prolapse

Our Raman probe that is called as ball-lens hollow fiber Raman probe (BHRP) had been proved possessing capability to detect the biochemical alteration within biological tissue. Whether BHRP has high capability and sensitivity in diagnosing the biochemical changing of tissue or not, mouses normal rectal and anorectal prolapse (AP) were decided to be used as a model for this non invasive method. This AP is azoxymethane and DSS-induced mouse’s anorectal prolapse. Main outcome of BHRP will be potential for non-invasive method in tumor diagnosing. BHRP spectra obtained were a high quality and allowed analysis of their differences between normal rectal (control group) and AP. After spectral acquisition and comparison with corresponding images of hematoxylin/eosinstained section observation used to make the histopathologic diagnosing, BHRP detected some differences within the region of moiety of DNA, protein (i.e. collagen) and lipid, then following with the alteration of symmetric P=O stretching vibration compared with the normal rectal tissue. BHRP discriminate normal tissue and AP in the real-time.

The study of esophageal cancer in an early stage by using Raman spectroscopy

The esophageal cancer is a disease with a high mortality. In order to lead a higher survival rate five years after the cancer’s treatment, we inevitably need a method to diagnose the cancer in an early stage and support the therapy. Raman spectroscopy is one of the most powerful techniques for the purpose. In the present study, we apply Raman spectroscopy to obtain ex vivo spectra of normal and early tumor human esophageal sample. The result of principal component analysis indicates that the tumor tissue is associated with a decrease in tryptophan concentration. Furthermore, we can predict the tissue type with 80% accuracy by linear discriminant analysis which model is made by tryptophan bands.

Ball lens hollow fiber Raman probe and Fourier transform infrared applied for studying non-clinic samples colorectal tumor models

Ball-lens hollow fiber Raman Probe (BHRP) and FTIR spectroscopy were main tools in this study. Thus, both of equipments detected the alteration of antisymmetric and symmetric P=O stretching vibration within our mice colorectal tumor models. Some differences of spectra due to randomly the edge of each BHRP and FTIR attached the surface of tumor during measurements. Meanwhile, the application of FTIR potentially differentiates the grade levels of non-clinic samples colorectal tumor models at four different grades (normal, grade 1, grade 2 and grade 3). Detailed investigations were assignable to wave numbers that publicized to represent biochemical alteration. The whole of investigated spectra in the fingerprint region revealed some different peaks and shoulders, most of which were assignable to wave numbers that exposed to represent biochemical alteration within the tissue. Differences in peak heights and peak ratio indicated differences in biochemical composition of cancer from different grade level. However, all collected colorectal tumor model at different peak was distinguishable, where antisymmetric and symmetric P=O stretching vibration was imaged and mapped clearly by both equipments. Therefore, BHRP were comfortable for in vivo studies. Meanwhile FTIR spectral analysis in combination with calibration curve might be used to distinguish cancer grade within colorectal tumor model tissue for ex vivo study.

Prospect of raman spectroscopy for biomedical application

Raman spectroscopy is a powerful tool for analyzing live biological samples without staining and labeling. In the present report, developments of instruments and analyzing methods, and their biomedical application studies, especially in live cells and animals are introduced.