Vibrational spectroscopic methods are widely used in the molecular diagnostics of carcinogenesis. Collagen, a component of connective tissue, plays a special role as a biochemical marker of pathological changes in tissues. The vibrational bands of collagens are very promising to distinguish between normal colon tissue, benign and malignant colon polyps. Differences in these bands indicate changes in the amount, structure, conformation and the ratio between the individual structural forms (subtypes) of this protein. The screening of specific collagen markers of colorectal carcinogenesis was carried out based on the FTIR and Raman (λex 785 nm) spectra of colon tissue samples and purified human collagens. It was found that individual types of human collagens showed significant differences in their vibrational spectra, and specific spectral markers were found for them. These collagen bands were assigned to specific vibrations in the polypeptide backbone, amino acid side chains and carbohydrate moieties. The corresponding spectral regions for colon tissues and colon polyps were investigated for the contribution of collagen vibrations. Mentioned spectral differences in collagen spectroscopic markers could be of interest for early ex vivo diagnosis of colorectal carcinoma if combine vibrational spectroscopy and colonoscopy.

• MeSH
• Collagen MeSH
• Colonoscopy * methods   MeSH
• Colorectal Neoplasms * diagnosis   MeSH
• Humans MeSH
• Spectrum Analysis, Raman methods   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Colorectal cancer is one of the most common and often fatal cancers in humans, but it has the highest chance of a cure if detected at an early precancerous stage. Carcinogenesis in the colon begins as an uncontrolled growth forming polyps. Some of these polyps can finally be converted to colon cancer. Early diagnosis of adenomatous polyps is the main approach for screening and preventing colorectal cancer, and vibration spectroscopy can be used for this purpose. This work is focused on evaluating FTIR and Raman spectroscopy as a tool in the ex vivo analysis of colorectal polyps, which could be important for the early diagnosis of colorectal carcinoma. Multivariate analyses (PCA and LDA) were used to assist the spectroscopic discrimination of normal colon tissue, as well as benign and malignant colon polyps. The spectra demonstrated evident differences in the characteristic bands of the main tissue constituents, i.e., proteins, nucleic acids, lipids, polysaccharides, etc. Suitable models for discriminating the three mentioned diagnostic groups were proposed based on multivariate analyses of the spectroscopic data. LDA classification was especially successful in the case of a combined set of 55 variables from the FTIR, FT Raman and dispersion Raman spectra. This model can be proposed for ex vivo colorectal cancer diagnostics in combination with the colonoscopic extraction of colon polyps for further testing. This pilot study is a precursor for the further evaluation of the diagnostic potential for the simultaneous in vivo application of colonoscopic Raman probes.

• Publication type
• Journal Article MeSH

Chiroptical methods are widely used in structural and conformational analyses of biopolymers. The application of these methods to investigations of biofluids would provide new avenues for the molecular diagnosis of protein-misfolding diseases. In this work, samples of human blood plasma and hen egg white were analyzed using a combination of conventional and chiroptical methods: ultraviolet absorption/electronic circular dichroism (UV/ECD), Fourier transform infrared absorption/vibrational circular dichroism (FTIR/VCD), and Raman scattering/Raman optical activity (Raman/ROA). For comparison, the main components of these substances--human serum albumin (HSA) and ovalbumin (Ova)--were also analyzed by these methods. The ultraviolet region of the ECD spectrum was analyzed using the CDNN CD software package to evaluate the secondary structures of the proteins. The UV/ECD, FTIR/VCD, and Raman/ROA spectra of the substances were quite similar to those of the corresponding major proteins, while some differences were also detected and explained. The conclusions drawn from the FTIR/VCD and Raman/ROA data were in good agreement with the secondary structures calculated from ECD. The results obtained in this work demonstrate that the chiroptical methods used here can be applied to analyze not only pure protein solutions but also more complex systems, such as biological fluids.

• MeSH
• Amino Acids chemistry   MeSH
• Circular Dichroism methods   MeSH
• Blood Proteins analysis   chemistry   MeSH
• Humans MeSH
• Spectrum Analysis, Raman methods   MeSH
• Protein Structure, Secondary * MeSH
• Serum Albumin analysis   MeSH
• Software MeSH
• Spectrophotometry, Ultraviolet methods   MeSH
• Spectroscopy, Fourier Transform Infrared methods   MeSH
• Stereoisomerism MeSH
• Egg White analysis   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Polysaccharide films containing chitosan, methylcellulose, and a mixture of these polysaccharides in various ratios were prepared and modified with meso-tetrakis(4-sulfonatophenyl)porphyrin in an aqueous medium at pH 7. The modified films were compared with the initial films using spectroscopic methods and microscopic imaging. Electronic (UV-vis absorption, electronic circular dichroism (ECD)) and vibrational (FTIR and Raman) spectra showed that the porphyrin macrocycles had a strong affinity toward chitosan and did not interact with the methylcellulose. The total porphyrin uptake depended on the chitosan: methylcellulose ratio and pure methylcellulose films did not retain porphyrin macrocycles. ECD measurements detected the presence of optically active porphyrin species bound to the films. SEM and AFM images confirmed that the porphyrin macrocycles caused structural changes on the film surface and within the film layer.

• MeSH
• Absorption MeSH
• Biocompatible Materials chemical synthesis   MeSH
• Chitosan chemistry   MeSH
• Circular Dichroism MeSH
• Hydrogen-Ion Concentration MeSH
• Drug Delivery Systems methods   MeSH
• Methylcellulose chemistry   MeSH
• Microscopy, Electron, Scanning MeSH
• Molecular Structure MeSH
• Porphyrins chemistry   MeSH
• Spectrum Analysis, Raman MeSH
• Spectroscopy, Fourier Transform Infrared MeSH
• Water MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH