Halina Abramczyk

Raman imaging at biological interfaces: applications in breast cancer diagnosis

BackgroundOne of the most important areas of Raman medical diagnostics is identification and characterization of cancerous and noncancerous tissues. The methods based on Raman scattering has shown significant potential for probing human breast tissue to provide valuable information for early diagnosis of breast cancer. A vibrational fingerprint from the biological tissue provides information which can be used to identify, characterize and discriminate structures in breast tissue, both in the normal and cancerous environment.ResultsThe paper reviews recent progress in understanding structure and interactions at biological interfaces of the human tissue by using confocal Raman imaging and IR spectroscopy. The important differences between the noncancerous and cancerous human breast tissues were found in regions characteristic for vibrations of carotenoids, fatty acids, proteins, and interfacial water. Particular attention was paid to the role played by unsaturated fatty acids and their derivatives as well as carotenoids and interfacial water.ConclusionsWe demonstrate that Raman imaging has reached a clinically relevant level in regard to breast cancer diagnosis applications. The results presented in the paper may have serious implications on understanding mechanisms of interactions in living cells under realistically crowded conditions of biological tissue.

IR νs(XH) Absorption band shape in H-bonded complex. I. Theory

Abstract The IR band shape theory of the stretching mode ν s (XH…Y) in H-bonded complexes is presented. The proton in the H-bond involves motion in the Born-Oppenheimer energy potential which is accompanied by the anharmonic coupling to the low-frequency hydrogen-bridge stretching motion ν σ . Both the energy potential well and the anharmonic coupling are randomly modulated with time. The fluctuations of the energy potential arising from the direct coupling to the bath obey the stochastic Liouville equation. The time evolution of the anharmonic coupling constant is governed by the resonance energy exchange between the ν σ mode and the bath. The theory can be applied both to weak and strong H-bonds.

Profiles of the νs(XH) mode in IR spectra of hydrogen-bonded complexes. Theoretical approach

Abstract A model describing the phase relaxation of the ν s (XH) mode of a hydrogen-bonded complex XH … Y in an inert solvent is presented. This model includes the coupling between the ν s (XH) and ν s (XH … Y) modes as well as dipole-dipole interactions between the molecular dipole moment μ directed along the (XH) axis and the dipole moment Δμ generated by hydrogen-bond formation. The model assumes that the dipolar coupling can be treated as a stochastic process due to thermal motions of molecules engaged in H-bonding. It is shown that both mechanisms are equally important. The model can be analyzed in terms of Kubos theory.

Phase transitions in oleic acid and in human breast tissue as studied by Raman spectroscopy and Raman imaging.

We present the results of differential scanning calorimetry (DSC) and Raman studies in the temperature range of 293-77 K on vibrational properties of the oleic acid and the human breast tissue as a function of temperature. We have found that vibrational properties are very sensitive indicators to specify phases and phase transitions at the molecular level. We have found that water content confined in the cancerous tissue is markedly different from that in the noncancerous tissue. The OH stretching vibrations of water are useful as potential Raman biomarkers to distinguish between the cancerous and the noncancerous human breast tissues. Our results provide experimental evidence on the role of lipid profile and cell hydration as factors of particular significance in differentiation of the noncancerous and cancerous breast tissues.

IR νs (XH) Absorption band shape of H-bonded complex in condensed media. II. Numerical calculations of the profiles

Abstract The IR absorption band profiles of H-bonded complexes in the spectral range 600–3600 cm −1 have been calculated in terms of the theory presented in the accompanying paper. We have considered the IR band profiles as a function of strength of the H-bond, the influence of the environment on the band shape and the effect of fluctuations of the energy potential well, in which the vibrational transition of the ν s (XH) mode occurs.

Ultrafast Dynamics of Metal Complexes of Tetrasulphonated Phthalocyanines

A promising material in medicine, electronics, optoelectronics, electrochemistry, catalysis, and photophysics, tetrasulphonated aluminum phthalocyanine (AlPcS(4)), is investigated by means of steady-state and time-resolved pump-probe spectroscopies. Absorption and steady-state fluorescence spectroscopy indicate that AlPcS(4) is essentially monomeric. Spectrally resolved pump-probe data are recorded on time scales ranging from femtoseconds to nanoseconds. The nature of these fast processes and pathways of the competing relaxation processes from the initially excited electronic states in aqueous and organic (dimethyl sulfoxide) solutions are discussed. The decays and bleaching recovery have been fitted in the ultrafast window (0-10 ps) and later time window extending to nanoseconds (0-1 ns). While the excited-state dynamics have been found to be sensitive to the solvent environment, we were able to show that the fast dynamics is described by three time constants in the ranges of 115-500 fs, 2-25 ps, and 150-500 ps. We were able to ascribe these three time constants to different processes. The shortest time constants have been assigned to vibrational wavepacket dynamics. The few picosecond components have been assigned to vibrational relaxation in the excited electronic states. Finally, the 150-500 ps components represent the decay from S(1) to the ground state. The experimental and theoretical treatment proposed in this paper provides a basis for a substantial revision of the commonly accepted interpretation of the Soret transition (B transition) that exists in the literature.

Human breast tissue cancer diagnosis by Raman spectroscopy

Differences between Raman spectra of normal, malignant and benign tissues have been recorded and analyzed as a method for the early detection of cancer. To the best of our knowledge, this is one of the most statistically reliable research (67 patients) on Raman spectroscopy-based diagnosis of breast cancers among the world women population. The paper demonstrates that Raman spectroscopy is a promising new tool for real-time diagnosis of tissue abnormalities.

Distribution of phthalocyanines and Raman reporters in human cancerous and noncancerous breast tissue as studied by Raman imaging.

There is a considerable interest in the developing new diagnostic techniques allowing noninvasive tracking of the progress of therapies used to treat a cancer. Raman imaging of distribution of phthalocyanine photosensitizers may open new possibilities of Photodynamic Therapy (PDT) to treat a wide range of neoplastic lesions with improved effectiveness of treatment through precise identification of malignant areas. We have employed Raman imaging and Raman spectroscopy to analyze human breast cancer tissue that interacts with photosensitizers used in the photodynamic therapy of cancer. PCA (Principal Component Analysis) has been employed to analyze various areas of the noncancerous and cancerous breast tissues. The results show that the emission spectra combined with the Raman images are very sensitive indicators to specify the aggregation state and the distribution of phthalocyanines in the cancerous and noncancerous breast tissues. Our results provide experimental evidence on the role of aggregation of phthalocyanines as a factor of particular significance in differentiation of the normal and tumourous (cancerous or benign pathology) breast tissues. We conclude that the Raman imaging reported here has a potential to be a novel and effective photodynamic therapeutic method with improved selectivity for the treatment of breast cancer.

Interaction-induced contribution to changes in the infrared spectrum of hydrogen-bonded complexes

Abstract An attempt to include interaction-induced effects into the study of absorption in H-bonded complexes is presented. The IR band shapes of the νs(OH) mode in phenol, 2,4,6-trimethylphenol, 2,6-dichloro-4-nitrophenol, and dimethylamine with nitriles or pyridine derivatives have been studied in terms of the dipolar coupling theory.

Raman study of vibrational relaxation of cyclohexane in benzene solutions

Abstract The Raman profiles of the ν 5 mode (802 cm −1 ) of cyclohexane, ν 5 (723 cm −1 ) of cyclohexane- d 12 and ν 2 (992 cm −1 ) of benzene and its deuterated analogs have been measured as a function of concentration in the benzene—cyclohexane liquid system. The vibrational time correlation functions of cyclohexane in benzene solutions have been calculated by Fourier inversion of isotropic band contours. The concentration dependence of the experimental vibrational correlation times computed from the correlation functions and from the half width at half height have been compared with that predicted theoretically for various mechanisms of band broadening. We have tested the Fischer—Laubereau dephasing model and the Knapp—Fischer concentration-fluctuation model. We have found that the latter model reproduces well experimental data only for the ν 2 mode of benzene in solution.