Biomedical Spectroscopy and Imaging - Volume 5, issue 2

Authors: Aluigi, A. | Sotgiu, G. | Torreggiani, A. | Zamboni, R. | Guerrini, A. | Varchi, G. | Orlandi, V.T.

Article Type: Research Article

Abstract: BACKGROUND: The design of wound dressings with extraordinary functionalities that fully address the problem of wound healing is an ambitious challenge in biomedical field. Keratin is a protein most abundant in nature, being the major component of wool, feather, hair, etc., with promising applications in biomedical and regenerative medicine fields. A high level of antibacterial functionality is another desirable property for applications in biomedical field in response to the increasing resistance of bacteria to antibiotics. One of the emerging methods of disinfection and sterilization is the antimicrobial photodynamic therapy (APDT), which uses light combined to a photosensitizer and oxygen to …produce phototoxic species. OBJECTIVE: Biomatrices (photo-active keratin) made of wool keratin functionalized with methylene blue, a powerful photosensitizer, have been developed and tested as systems that combine the bioactive properties with the antimicrobial photodynamic functionality. METHODS: The biomatrix resistance to photo-degradation and the formation of reactive oxygen species were evaluated by spectroscopic methods, whereas the antibacterial properties were tested towards gram-positive bacteria. RESULTS: The Raman analysis revealed that specific damages occur at sensitive amino acid sites, selectively, rather than indiscriminately. However, keratin resulted to be a suitable biomaterial for APDT, since it has enough resistance to photo-degradation and the radical-induced oxidation is not able to induce strong structural changes in the protein. CONCLUSIONS: The results clearly indicate the potential use of these novel photo-active keratin biomatrices in wound dressing and tissue engineering. Show more

Keywords: Keratin, reactive oxygen species, antimicrobial photodynamic activity, Raman spectroscopy

DOI: 10.3233/BSI-160143

Citation: Biomedical Spectroscopy and Imaging, vol. 5, no. 2, pp. 207-215, 2016

Authors: Elka, Aspasia | Moulia, Violetta | Spyridonos, Panagiota | Kourkoumelis, Nikolaos

Article Type: Research Article

Abstract: Background: The successful discrimination of the subtle spectral characteristics of human skin in Raman spectra requires optimal acquisition parameters. We explore the translational momentum of Raman spectroscopy towards clinical practice by fine-tuning two basic experimental parameters (irradiance and integration time) of a portable Raman system used in skin measurements. Objective: The aim of this study is to construct a generic protocol for recording the optimal Raman signal for in vivo skin measurements. Methods: In vivo spectra were collected from two individuals of normal Fitzpatrick type III skin type. We assessed two different irradiation setups …with three different integration times each by separating the raw signal from the noise using multivariate analysis. Results: Our results showed that under a time threshold no optimal measurement conditions can be achieved. On the other hand, increased laser power and acquisition time do not offer a significant advantage over the selected lower values. Baseline correction is the most critical component for analysing normalized skin Raman spectra. Conclusions: A simple working protocol based on multivariate statistics offers the relative adjustment of irradiance and signal integration time among other experimental parameters that must be examined for optimal Raman measurements of skin. Show more

Keywords: Raman spectroscopy, in vivo spectroscopy, skin, multivariate statistical analysis, PCA

DOI: 10.3233/BSI-160140

Citation: Biomedical Spectroscopy and Imaging, vol. 5, no. 2, pp. 217-223, 2016