IR microspectral maps of healthy an diseased live tissue are reported, along with the methodology for obtaining such maps and methods for their interpretation. The result suggest that present technology permits maps to be collected that contain useful pathological information.

Vibrational spectra in the mid-IR region show significant and reproducible correlation with the disease state of the blood donor. When focusing our 'disease pattern recognition (DPR)' approach onto the example of diabetes mellitus we can clearly separate samples obtained from healthy volunteers from those samples which organized from diabetes patients. Furthermore, we are able to differentiate between samples of type-1 diabetics and type-2 diabetics. For disease pattern recognition we use linear and/or regularized discriminant analysis. In a binary, supervised classification of an pair of the three disease states: healthy, diabetes type-1 and diabetes type-2, we consistently achieve sensitivities and specificities >= 80 percent. By setting stricter bounds on the range of acceptable probabilities of belonging to a certain class, we obtain even higher values for the sensitivity and the specificity on the expense of the fraction of 'crisply' classified samples. Since we are able to simultaneously quantify the concentrations of biochemical serum components like glucose, cholesterol and triglycerides from the identical set of spectra with regression coefficients > 90 percent, our approach allows for a direct cross-link between the molecule-based and the disease-based interpretation of the spectra.

The feasibility of characterizing human colorectal adenocarcinoma by IR microspectrometry is described. Carcinoma thin sections were analyzed by spatially resolved mid-IR FT microspectrometry, and for comparative purposes by conventional histological staining techniques. More than 2300 high quality FTIR reference spectra of 27 patient samples form 11 defined morphological structures such as crypts, tunica muscularis, submucosa and adenocarcinoma were recorded. The analysis of the spectral data included four steps: an initial test for spectral quality, data preprocessing, data reduction and classification of the tissue spectra by pattern recognition techniques. The overall classification accuracy attainted by an optimized ANN of about 95 percent highlights the great potential of FTIR microspectrometry as a diagnostic tool for the determination of a variety of tissue structures. Further improvements are necessary to make the new method applicable to routine and experimental clinical analysis in the future.

The major objective of the project is to develop a noninvasive method to assess thermal burns. Currently, the diagnosis relies primarily upon visual assessment of the injury by a burn specialist and/or plastic surgeon. The diagnosis is based on the surface appearance of the wound to determine the type or depth of the burn. Near IR spectroscopic measurements of injured tissue provide an objective means of distinguishing between surface and subsurface changes related to the tissue injury. An acute porcine model is employed to investigate the potential of near IR spectroscopy to accurately distinguish between burns of varying severity in the early postburn period. Parallel factor analysis is used to investigate the spectral changes related to burns of varying severity. Burn injuries drastically alter the physical and optical properties of the tissue. Thermal destruction of cutaneous vasculature disrupts perfusion and oxygen delivery to the affected tissue. Tissue blood oxygenation decreases with increased severity of the burn. The result demonstrate that near IR spectroscopy may provide a new tool for objective clinical assessment of burn injuries.

IR spectra of intact microbial cells are fingerprint-like signatures which provide multi-dimensional information on cell composition and structure. These spectral signatures are already used in practice to identify divers microbial species and strains, to characterize particular cell compounds in situ, and to monitor cell-drug interactions. New applications arise by means of a light microspace coupled to the IR spectrometer: IR-spectra of micro-colonies containing a few hundred cells can be obtained from colony replica by a stamping technique that transfers spatially accurate micro-colonies growing on solid culture plates to a special, IR-transparent stamping device. Using a computer controlled x, y stage together with spectral mapping and video techniques, detection, enumeration, and differentiation of micro-organisms are integrated in one single apparatus, providing diagnostic results within one working day. Additional items of the new are integrated in one single apparatus, providing diagnostic result within one working day. Additional items of the new approach are (i) rapid sensitivity and resistance testing against various antimicrobial drugs, and (ii) the conductance of spectral mapping analysis on single colonies enabling the spatially resolved characterization of growth heterogeneity within complex populations of micro-organisms.

FTIR spectroscopy of proteins has the unusual disadvantage of providing too much information. Thousands of individual bands contribute to the spectrum, leading to an overlap so extensive that essentially all detail is obscured. FTIR difference spectroscopy is a perturbation approach designed to overcome this problem: instead of the compete FTIR spectrum, only the changes in the spectrum in response to a biologically interesting perturbation of the same are recorded. The resulting difference spectra are far simpler than complete IR spectra, and thus can be interpret at the level of individual molecular bonds. But at the same time, they retain all the information pertaining to the structural dynamics related to the protein's catalytic cycle, and are thus of direct relevance to the study of molecular mechanisms in protein reactions. This paper presents our recent progress in the development of electrochemical, rapid mixing and flow techniques as triggers for FTIR difference spectroscopy, and the potential of such techniques as an analytical tool for biomedical research and in clinical diagnostics.

The purpose of this study is to assess if Raman spectroscopy can classify dysplastic (DYS) and early neoplastic lesions within Barrett's esophagus (BE). In BE, the normal squamous epithelium (SQ) lining the esophagus is replaced by columnar epithelium. These patients have a 30-125 fold excess risk of developing adenocarcinoma. Raman spectroscopy may provide diagnostic information so that tissue transformation may be detected at an early stage and improve the patient's prognosis. Ex vivo measurements were carried out initially on biopsy samples obtained from BE patients undergoing routine endoscopic and biopsy surveillance. Differences were noted in the spectral regions 1200-1350 cm^-1 and 1550-1640 cm^-1 when comparing different histopathologic grades. Principal component analysis of the spectra led to good separation between SE and BE but not between BE and DYS. Improved results were obtained using a probabilistic artificial neural network, with a resultant sensitivity and specificity of 77 percent and 93 percent in differentiating SQ/BE from dysplasia, respectively. Recently, in vivo endoscopic measurements have been performed. These preliminary results indicate that RS in combination with endoscopy may be a useful technique to screen BE patients for dysplastic/early neoplastic lesions.

Early detection of cancer is important because of the improved survival rates when the cancer is treated early. We study the application of NIR Raman spectroscopy for detection of dysplasia because this technique is sensitive to the small changes in molecular invasive in vivo detection using fiber-optic probes. The result of an in vitro study to detect neoplastic progress of esophageal Barrett's esophageal tissue will be presented. Using multivariate statistics, we developed three different linear discriminant analysis classification models to predict tissue type on the basis of the measured spectrum. Spectra of normal, metaplastic and dysplasia tissue could be discriminated with an accuracy of up to 88 percent. Therefore Raman spectroscopy seems to be a very suitable technique to detect dysplasia in Barrett's esophageal tissue.

The incidence of laryngeal cancer has risen progressively over the last 25 years. Early diagnosis and treatment of premalignant lesions of the larynx is vital to prevent progression to invasive squamous cell carcinoma. In the larynx, it has long been recognized that histological evidence of maturation abnormality is associated with a higher risk of transformation to malignancy. Currently, it is extremely difficult if not impossible for the clinician to ascertain the level of abnormality present without removing a biopsy sample and sending it for histopathological analysis. Inherent risks with this technique include damage to vocal chords and loss of speech quality as well as possible selection of unrepresentative biopsy samples. Raman spectroscopy, incorporated into an endoscopic system, has the potential to provide a real-time, non-invasive diagnostic technique able to detect biochemical changes that accompany abnormal pathology. Likely outcomes would be improved biopsy targeting and patient management by providing immediate result of tissue pathology. This paper demonstrates the capacity of near IR Raman spectroscopy combine with statistical data analysis techniques to discriminate between normal, dysplastic and cancerous laryngeal tissue.

With an overall survival rate of about 35 percent, ovarian cancer claims more than 13,000 women in the US each year. It is estimated that roughly 1 in 70 women will develop ovarian cancer. Current screening techniques are challenged due to cost-effectiveness, variable false-positive results, and the asymptomatic nature of the early stages of ovarian cancer. The predominant screening method for ovarian cancers is transvaginal sonography (TVS). TVS is fairly accomplished at ovarian cancer detection, however it is inefficient in distinguishing between benign and malignant masses. Accurate diagnosis of the ovarian tumor relies on exploratory laparotomy, thus increasing the cost and hazard of false- positive screening methods. Raman spectroscopy has been sued successfully as a diagnostic tool in several organ systems in vitro. These studies have shown that Raman spectroscopy can be used to provide diagnosis of subtle changes in tissue pathology with high accuracy. Based on this success, we have developed a Raman spectroscopic system for application in the ovary. Using this system, the Raman signatures of normal and various types of non-normal human ovarian tissues were characterized in vitro. Raman spectra are being analyzed, and empirical as well as multivariate discriminatory algorithms developed. Based on the result of this study, a strategy for in vivo trials will be planned.

We report significant differences in UV resonance Raman (UVRR) spectra of DNA samples from normal and cancerous tissues. The four bases of DNA, adenosine, thymine, guanosine and cytidine, can be enhanced in UVRR spectra, and their intensities are very sensitive to base stacking and DNA H-bonding. 14 DNA samples from patients at different stages of ovarian cancer, 5 from normal, 2 from primary, 3 from metastasis primary and 4 from distant metastasis tumor tissues, were characterized by 257, 238, 229, 220 and 210 nm-excited UVRR spectra. Raman spectral difference between normal and tumor DNA could be readily detected.

This study shows a first application of Raman microspectroscopy to the study of thyroid tissue samples classified as carcinomas, adenomas and nodules. Treatment of the Raman data using statistical methods show that it is possible to classify most of the samples in accord with the pathological examinations. Furthermore, Raman spectral image based on specific bands or frequencies defined as 'functional descriptors' allow to construct maps of micro- zones of such tissues. Such maps can be useful as complementary tools for tissue diagnosis and prognosis, since they carry molecular information important to such ends.

The biological polymers extracted from brown algae, alginates, are novel materials in biotechnology and biomedicine. Their ability to form viscous gels is used to immobilize or encapsulate yeast, enzymes, living cells and drugs. Calcium-alginate fibers are extensively used in wound dressings since exhibit antihaemostatic and healing properties. The problem with alginate-made dressings in surgery is their slow biodegradability: if entrapped within tissues, they can induce a local cellular recruitment with an inflammatory response contemporaneous to the resorption phase. In part, this problem is a consequence of poor solubility of the calcium alginates in water. Although calcium alginate fibers can exchange calcium ions with sodium ions from the wound exudate to create a calcium/sodium alginate fibers, the residual alginates are thought to be not totally degradable in vivo. Rapid and non- destructive characterization of series of the crude alginates and calcium alginate fibers has been performed using Raman spectroscopy with near IR excitation. Study of structural organization of the polymeric chains within calcium alginate fibers have been previously reported as made by confocal Raman multispectral imaging (CRMSI) in visible. Here, the Raman approach has been used to monitor the ion exchange reactions for different types of alginates and their salts in vitro. For in vivo evaluation, histological sections of alginate-treated rat tissue have been analyzed by light microscopy and CRMSI. The in vitro Raman modeling and the histochemical mapping were a necessary precursor for application of the Raman microprobe to follow in a non-invasive way the alginate-cell molecular interactions in rat tissue.

Near IR Raman spectroscopy has been successfully used to analyze major metabolites in simulating human serum samples quantitatively. We demonstrated that the optical waveguide based Raman cell and signal collector can significantly improve the collection efficiency of inherently weak Raman signal. The acquisition time for the Raman signal with decent SNR has been reduced to 10 seconds. The sample container, a quartz capillary with length of 20 mm and diameter of 400 micrometers , is easy to produce and disposable. The Raman signal was normalized to the dominant water peak at 3350 cm^-1. This self-calibration method makes the measurement insensitive to the fluctuation of the excitation and misalignment of the collection system. A partial least squares method was used to predict the analyte concentrations of interest in the simulating human sera. The prediction accuracy of albumin, globulin, triactin, urea and glucose is greatly acceptable for clinical diagnostics. The results of this research encourage the development of practical Raman system for clinical diagnostics.

The detection of sever brain trauma remains difficult when employing traditional methods in part due to the pathophysiological complexity of the condition. Current brain trauma detection includes schemes that require bulky, expensive equipment to deduce regional cerebral blood flow. These methods are difficult to use in conjunction with patients requiring ongoing intensive care and constant monitoring. Our previous studies have shown that surface- enhanced Raman spectroscopy (SERS) with silver colloids has the ability to measure physiological concentrations of in vivo brain analytes linked to brain trauma using short scan times. More recently, after implementing a damage model for ischemia in rats, an ex vivo analysis of brain microdialysis samples shows a correlation between SERS spectral features and the occurrence and location of known localized ischaemia. A near real-time measurement system could provide relevant clinical information in anticipation of surgical or pharmaceutical interventions for severely head injured patients.

The recent development of Scanning Near-Field IR Microscopy (SNIM) has resulted in the first ever high-resolution IR images of single living cells. We discuss extensions of this method using table-top tunable OPO-based ultrafast lasers and other tunable lasers as sources. Vibrational spectral provide an intrinsic mechanism of contrast in biological systems, without the need for any radioactive or fluorescent labels. Using the capability of SNIM for obtaining sub- wavelength resolution images and spectral allows for breaking of the femtogram barrier in biological systems. This provides a new technique for imaging sub-cellular features, and characterization of a single bacterium.

We have developed methods for embedding miniature planar IR sensor elements flush at the surface of rigid substrates. The planar Ge waveguides have thicknesses down to approximately 10 micron, and widths of 0.5-1 mm. These waveguides are tapered in thickness along their 50-mm lengths to permit efficient coupling of light into the approximately 10 micron sensing region without requiring an IR microscope. The waveguides can therefore be positioned with their sensor surface horizontal. Such waveguides can be used as mid-IR evanescent-wave sensor elements for small biological samples. They display exquisite sensitivity to small numbers of analyte molecules at their surface. It is possible to collect high-throughput broadband spectra, e.g. of tiny liquid droplets or membranes of individual cells, in a matter of seconds.

Raman microspectroscopy and imaging can be used to probe the chemical properties of newly mineralized bone tissue. In this study, our early mineralization models are neonatal murine cranial suture tissue and prostate cancer cell cultures. The murine cranial tissue was harvested from animals three weeks postnatal. On this time scale, remodeling does not corrupt the temporal record inherent in the spatial distribution of mineral species. When analyzing transects, line images, of the cranial tissue, multivariate data processing is required to generate chemical state plots from the hundreds of Raman spectra acquired during a single transect experiment. In most cranial tissue specimens more than one phosphate mineral environment is observed, allowing inferences on the relation between chemical structure and physiologically important properties. The prostate cancer cell cultures were cultured for up to nine days. Point microspectroscopy reveals the ratios of mineral species present and the amount of protein species in the cell cultures changes dramatically over the course of 9 days. Very low carbonation, typical of early-mineralized tissue, is observed in both of these models.

IR spectroscopy represents only one section of the entire vibrational spectrum of molecules. Due to the nature of the material analyzed, IR spectra of cell sand tissues always contain features of proteins, lipids, DNA/RNA, carbohydrates and of many small metabolites. The distinction of different tissue structures is achieved by comparing those spectral features, using the fact that cells vary in their chemical composition and therefore also in their spectra. Although cells are composed of different biomolecules, the spectral features expressed in IR spectra normally vary only slightly but are most often more than sufficient for analysis. However, this is where Raman spectroscopy may help enhance the differentiation capabilities of vibration spectroscopy. In contrast to IR spectroscopy, Raman spectroscopy only provides information on some of the many cellular biomolecules, thereby being very specific. Conjugated double bonds, aromatic rings and bonds between heavier atoms can be seen as very sharp features in Raman spectra of biomolecules and cells. In some cases even the distribution of drugs can be cartographed in lining cells. Generating IR and Raman images with similar spatial resolution of the same tissue sections may improve the diagnostic capabilities possible with either spectroscopic method alone. Gland tissue sections are presented and analyzed for the distribution of typical cell components and specific molecules such as thyroglobulines and precursors. In addition, fiber optics measurements on tissue sections in vitro are introduced to illustrate the power of the combination of FT-Raman and FT- NIR fiber optics technology. The use of single band analysis, bivariate statistics and cluster analysis applied to spectra from both spectroscopy methods will be assessed in this study and employed to illustrate the concept.

Leptospirosis is one of the most harmful zoonosis, it is a serious public health issue in some area of Sichuan province. Surface-Enhance Raman Scattering (SERS) Spectroscopy is an effective approach for the study of biomolecular adsorption on metal surface and provides information about the adsorbed species. Two samples of Leptospiral Glycolipoprotein (GLP-1) and GLP-2 which have different toxic effects have been obtained and investigated.

Lipid bilayers containing the nicotinic acetylcholine receptor were investigated by attenuated total reflection (ATR) FTIR spectroscopy and by surface plasmon resonance (SPA). FTIR-ATR spectra reveal structural details of the transmembrane protein. Surface enhanced IR absorption provides access to structural details in the close vicinity of the surface of the ATR crystal. Information about the abundance of protein substructures as well as about the orientation of those substructures are obtained. SPR was applied in order to detect changes within the adsorbed biomembrane during admission of a neurotransmitter as acetylcholine. Switching of the ion channel was successfully by SPR. This result is a step forward towards highly selective biosensors and bioactuators.

The diagnosis of prostate cancer is based on the visible microscopic evaluation of both cytological and architectural features of the prostate tissue sections. In order to determine whether IR spectral 'mapping' can be used to objectively distinguish between normal and neoplastic prostate tissue, a comparison between 'visual, point-by- point' and 'automated, point-by-point' IR measurements was performed. Automated, point-by-point analysis was performed without any prior diagnostic information. Visual, point-by- point measurements were based on histopathology, histochemistry and immunohistochemical analysis of the tissue samples. The spectra obtained from these measurements were compared to the spectra obtained from automated point- by-point analysis. Our results indicate that the spectra obtained from histopathologically directed measurements compares well with those of automated mapping methods. Therefore, we believe that current mapping methodology can be directly correlated with pathological diagnoses.

An IR spectroscopic study was carried out at room temperature for Human Serum albumin (HSA) glycated with fructose and glucose and inhibited with acetylsalicylic acid. The glycation process was carried out in our laboratory by a conventional method to confirm earlier reported observation of the effect of glycation on the intensity variation of the IR spectra, particularly, in the range 1500 cm^-1 to 1700 cm^-1 and around 3300 cm^-1. IR spectra reveal that the effects of glycation of HSA by fructose are more intense than with glucose, which is the expected. Bovine serum albumin was also glycated using Glucose-6-phosphate disodium salt, and gamma-globulin was glycate with glucose, As expected, the glycation process was more intense with glucose-t-phosphate disodium salt. Acetyl salicylic acid was also used and its inhibitor effects could be observed in both cases, with glucose and with glucose-6-phosphate disodium salt even though, to a smaller extent with the latter. This is consistent with the earlier data and is explained on the basis of the attachment of macromolecules to (epsilon) -NH₂ groups of lysines. The experimental results confirm that acetylsalicylic acid, indeed, acts as an inhibitor by acetylation of the (epsilon) -NG₂ group where the sugars are supposed to be attached.

Trabala vishnou Nuclear Polyhedrosis Virus is one kind of insect virus. It was found in Chengdu area of southwest China. The surface-enhanced Raman scattering (SERS) spectra of virion protein adsorbed on the silver surface and the SERS spectra influenced by the pH value of silver hydrosols have been obtained and analyzed.

Presented results of experimental and clinical work on implementation of the PNC - diagnostics being developed in treatment of large number of diseases. The method is based on measurement and indication of secondary emissions and their fields coming into being in the process of interaction of probing irradiation with tissue structure and its biologically active elements. This process of transformation of emissions we called the Photon-Undulatory Nonlinear Conversion, in short - the PNC - process.

Except for amplitude, the near IR spectra recorded through intact scalp and skull were identical to those from brain surface recordings. Reduction of scattering due to hypoxia was clearly evident in nitrogen induced spectra. Absorbance peaks, hemoglobin and aa₃, were visible and did not seem to be affected by percentage of deoxyhemoglobin. The 600 nm peak is believed to be caused by scattering, not aa₃ absorbance. Work is continuing to further demonstrate the validity of the hemoglobin and aa₃ absorption peaks.

Near IR Raman spectroscopy was used to investigate the effect of synthetic androgen R1881 on the androgen- responsive cell line LNCaP. The comparison between Raman spectra of the cell sunder androgen deprived conditions and in the presence of different concentrations of R1881 shows changes mainly in the concentration of lipids and DNA content. The androgen-unresponsive prostate cell line PC3 was used as a control. Our results demonstrate that in LNCaP cells R1881 induces an intracellular accumulation of lipids and leads to a relative decrease in DNA content. These changes could potentially be used as criteria to differentiate between responsive and unresponsive cell lines because they were not observed in the androgen unresponsive cell line PC3. We have also measured Raman spectra of lipid droplets directly in single living LNCaP cells, grown in the absence or in the presence of R1881 by Raman spectrometry. These droplets accumulate in cells grown in the presence of R1881. Our results show indeed that the main components in droplets were lipids and suggest that the surrounding cytoplasm does not significantly contribute to these Raman spectra. The major classes of lipids droplets affected by androgen were triglyceride and cholesterol linoleate.

Fourier transform IR spectroscopy of normal and cancerous human oral tissues have been studied in the mid IR frequency region. From this study, we observed that the cancerous tissues are having higher absorption than that of normal one. Further it is observed that there is a 13 cm^-1 red shift for cancerous samples with respect to normal tissues at their maximum absorption. In order to quantify the spectral differences between normal and cancerous tissues, two ratio parameters R₁ equals I₁₆₅₀/I₁₅₄₆ and R₂ equals I₁₆₅₀/I₁₃₈₄ are introduced. From the ratio parameter R₁, it is found that the critical value 2.1 classify the malignant from normal with a 93 percent sensitivity and 80 percent specificity. Similarity a critical value 3 is given for the ratio parameter R₂ yielding 80 percent sensitivity and 100 percent specificity.

FTIR employs a unique approach to optical diagnosis of tissue pathology based on the characteristic molecular vibrational spectra of the tissue. The architectural changes in the cellular and sub-cellular levels developing in abnormal tissue, including a majority of cancer forms, manifest themselves in different optical signatures, which can be detected in IR spectroscopy. The molecular vibrational modes, which are responsible for IR absorption spectra, are characteristic of the biochemistry of the cells and their sub-cellular components. The biological systems we have studied include adenocarcinoma and normal colonic tissues obtained from the department of pathology at Soroka Medical Center. Our method is based on microscopic IR study of thin tissue specimens and a direct comparison with normal histopathological analysis, which serves as a 'gold' reference. Several unique differences between normal and cancerous intestinal specimens have been observed. The cancerous intestine has weaker absorption strength over a wide region, which includes several significant vibrational bands. The results from microscopic IR absorption spectra from intestinal tissues have also been compared with other biological tissue samples.

We report the first noninvasive Raman spectra of in vivo human blood. 'Tissue modulation' involves the use of thermal and/or mechanical stimulus to produce particular spatiotemporal distributions of mobile tissues, i.e. capillary blood, among nonmobile tissues, i.e. epidermis. Using this approach we have obtained three mutually independent lines of evidence, which unequivocally associate Raman spectra we have obtained with human blood. These spectral compare well with published spectra from other researchers of in vitro human blood. The results of a recent clinical study comparing our noninvasive in vivo spectroscopic measurements with simultaneous conventional in vitro measurements clearly demonstrate the efficacy of the tissue modulation approach. These results will be discussed in the context of noninvasive monitoring of a variety of analytes, i.e. glucose.

We describe a non-invasive, in vivo hyperspectral imaging method for visualizing the spatial distribution of dermal tissue oxygenation. Real-time images of the dermis are acquired both at multiple, contiguous wavelengths and at relatively narrow spectral bandwidths to generate a data cube consisting of one spectral and two spatial dimensions. For data collection, the sample area is illuminated by radiation, which is delivered by liquid light guides from a quartz tungsten halogen source. Reflected light from the sample is first passed through a liquid crystal tunable filter and then imaged onto a silicon charged coupled device detector. The subsequently digitized data are presented in terms of spectral images reflecting multivariate least squares analyses based upon linear combinations of oxy- and deoxyhemoglobin reference spectra. The generated gray scale images directly represent the varying spatial distributions of dermal tissue oxygenation. As an example, imaging data are obtained from normal tissue and induced ischemic tissue for which both the venous and arterial blood flow was artificially occluded.

Vibrational spectroscopy, when combined with synchrotron radiation-based (SR) microscopy, is a powerful new analytical tool with high spatial resolution for detecting biochemical changes in the individual living cells. In contrast to other microscopy methods that require fixing, drying, staining or labeling, SR-FTIR microscopy probes intact living cells providing a composite view of all of the molecular response and the ability to monitor the response over time in the same cell. Observed spectral changes include all types of lesions induced in that cell as well as cellular responses to external and internal stresses. These spectral changes combined with other analytical tools may provide a fundamental understanding of the key molecular mechanisms induced in response to stresses created by low- doses of chemicals. In this study we used the high spatial - resolution SR-FTIR vibrational spectromicroscopy as a sensitive analytical tool to detect chemical- and radiation- induced changes in individual human cells. Our preliminary spectral measurements indicate that this technique is sensitive enough to detect changes in nucleic acids and proteins of cells treated with environmentally relevant concentrations of dioxin. This technique has the potential to distinguish changes from exogenous or endogenous oxidative processes. Future development of this technique will allow rapid monitoring of cellular processes such as drug metabolism, early detection of disease, bio- compatibility of implant materials, cellular repair mechanisms, self assembly of cellular apparatus, cell differentiation and fetal development.

The in situ investigations of living cells are among the most exciting biomedical applications of the confocal multispectral imaging (CMSI). The latter is often noted as chemical imaging since provides structurally specific information. This allows non-invasive mapping of molecular components of the cells or intracellular distribution of small Raman-active chromophores such as drugs, ion-markers, etc. Here, we attempt a comparative analysis of the major advantages and limitations of surface-enhanced Raman (SER) and non-enhanced Raman techniques as used for intracellular CMSI. Based on our experimental observations and on recent data from literature we conclude that, depending on application, the differences between the two methods can be dramatic and a choice of the proper approach is imposed during acquisition, treatment and interpretation. Moreover, while Raman and SER signal can be present on the same image, these however should be treated separately, in the different way. We discuss particularities of the mapping algorithms we use to generate Raman/SER images. Concerning SER, we compare different SER-active substrates in terms of imaging on cells, taking into account both principal and practical questions.