The use of 5-aminolevulinic acid and its derivatives in photodynamic therapy and diagnosis

5-aminolevulinic acid (5-ALA) is used as a drug in the photodynamic therapy (PDT) and photodynamic diagnosis (PDD) of cancer. Combined with irradiation at the appropriate wavelength, it is used as a photosensitizer precursor to identify/kill tumour cells. In cells, 5-aminolevulinic acid is converted to protoporphyrin IX (PpIX), which is the precursor of hemin. Internal application of 5-ALA induces the overproduction of the endogenous photosensitizer, PpIX, which can subsequently be activated by light at the appropriate wavelength. 5-ALA can be applied internally to trans-mutated areas or be injected directly into them. Chemical derivatives of 5ALA have the potential to improve bioavailability, enhance stability and lead to better therapeutic outcomes for treated patients. 5-ALA is currently the most commonly used drug in the photodynamic therapy and diagnosis (PDT/PDD) of cancers. Keywords: photodynamic therapy, photodynamic diagnosis, 5-aminolevulinic acid (5- ALA), esters of 5-aminolevulinic acid, cancer

An overview of the evolution of infrared spectroscopy applied to bacterial typing

The sustained emergence of new declared bacterial species makes typing a continuous challenge for microbiologists. Molecular biology techniques have a very significant role in the context of bacterial typing, but they are often very laborious, time consuming and eventually fail when dealing with very closely related species. Spectroscopic-based techniques appear in some situations as a viable alternative to molecular methods with advantages in terms of analysis time and cost. Infrared and mass spectrometry are among the most exploited techniques in this context: particularly, infrared spectroscopy emerged as a very promising method with multiple reported successful applications. This article presents a systematic review on infrared spectroscopy applications for bacterial typing, highlighting fundamental aspects of infrared spectroscopy, a detailed literature review (covering different taxonomic levels and bacterial species), advantages and limitations of the technique over molecular biology methods and a comparison with other competing spectroscopic techniques such as MALDI-TOF MS, Raman and intrinsic fluorescence. Infrared spectroscopy possesses a high potential for bacterial typing at distinct taxonomic levels and worthy of further developments and systematization. The development of databases appears fundamental towards the establishment of infrared spectroscopy as a viable method for bacterial typing.FCT -Fundação para a Ciência e a Tecnologia(PT2020 UID/QUI/50006/2013)info:eu-repo/semantics/publishedVersio

Optical Methods of Methane Detection

Methane is the most frequently analyzed gas with different concentrations ranging from single ppm or ppb to 100%. There are a wide range of applications for gas sensors including urban uses, industrial uses, rural measurements, and environment monitoring. The most important applications include the measurement of anthropogenic greenhouse gases in the atmosphere and methane leak detection. In this review, we discuss common optical methods used for detecting methane such as non-dispersive infrared (NIR) technology, direct tunable diode spectroscopy (TDLS), cavity ring-down spectroscopy (CRDS), cavity-enhanced absorption spectroscopy (CEAS), lidar techniques, and laser photoacoustic spectroscopy. We also present our own designs of laser methane analyzers for various applications (DIAL, TDLS, NIR)

Antibacterial properties of graphene and its derivatives

Praca prezentuje przegląd literatury w zakresie zastosowania grafenu i jego pochodnych do potencjalnej ochrony przed mikroflorą bakteryjną. Poruszono zagadnienia związane z próbą wyjaśnienia mechanizmów oddziaływania grafenu i jego pochodnych: tlenku grafenu (GO) oraz zredukowanego tlenku grafenu (rGO) na komórki bakteryjne. Porównano działanie poszczególnych form węgla na komórki Gram(+) i Gram(-), uwzględniając stężenie preparatów, rodzaj pożywki hodowlanej, a także podłoże, na którym osadzono grafen. Omówiono zagadnienia związane z powstawaniem wolnych form tlenowych (ROS), efekt ostrej krawędzi, tworzenie biofilmu oraz potencjalne zastosowania grafenu jako powłoki antybakteryjnej.The work presents a literature review on the use of graphene and its derivatives as the potential protection against bacterial microflora. Addressed issues relate to an attempt to explain the mechanisms of impact of graphene and its derivatives: graphene oxide (GO) and reduced graphene oxide (rGO) on the bacterial cells. Interaction of graphene materials (G, GO, rGO) with Gram(+) and Gram(-) were compared with regard to the concentration of the preparations, the nature of the culture medium and surface of graphene deposition. Issues related to the development of reactive oxygen species (ROS) were discussed, the effect of sharp edges of GM’s (nano-knife), biofilm formation and the potential application of graphene in nanomedicine

Applications of Laser-Induced Fluorescence in Medicine

Fluorescence is the most sensitive spectroscopic method of analysis and fluorescence methods. However, classical analysis requires sampling. There are new needs for real-time analyses of biological materials, without the need for sampling. This article presents examples of proprietary applications of laser-induced fluorescence (LIF) in medicine with such methods. A classic example is the analysis of photosensitizers using the photodynamic treatment method (PDT). The level and kinetics of accumulation and excretion of sensitizers in the body are examined, as well as the optimal exposure time after the application of compounds. The LIF method is also used to analyze endogenous fluorophores; it has been used to detect neoplasms, e.g., lung cancer or gynecological and dermatological diseases. Furthermore, it is used for the diagnosis of early stages of tooth decay or detection of fungi. The article will present the construction of sensors based on the LIF method—fiber laser spectrometers and investigated fluorescence spectra in individual applications. Examples of fluorescence imaging, e.g., dermatological, and dental diagnostics and measuring systems will be presented. The advantage of the method is it has greater sensitivity and easily detects lesions early compared to the methods used in observing the material in reflected light.</jats:p

Spectroscopic Studies of Baltic amber&mdash;Critical Analysis

Using optical spectroscopy methods including absorption in the UV-VIS, FTIR, Raman, and fluorescence, the spectra of 25 different Baltic amber samples were measured, and the ability of each method to distinguish between thermally modified and naturally aged material was analyzed. The natural ambers studied are characterized by a wide range of spectral properties: the position of the transmission edge in the UV-VIS spectra, the absorbance ratios of the C-H and C=O groups in the IR spectra, a difference of approximately 20% in the fluorescence intensity level, and differences in the band ratios in the C=C and C-H bonds in the Raman spectrum. Spectral studies were carried out on samples of natural and thermally modified amber at temperatures of 100, 150, and 200 &deg;C for 2&ndash;8 h. Drastic changes occur at temperatures above 150 &deg;C: the color changes to dark brown, the UV-VIS transmission edge shifts, the absorbance of the C=O group increases, the absorbance intensity of the C=C bond decreases, and fluorescence disappears. In some special cases, fluorescence methods allow for the unambiguous distinction of amber from different geographical regions (e.g., Baltic and Dominican). Spectroscopic methods can distinguish natural amber from thermally modified amber only for large changes in the spectrum at temperatures of 150&ndash;200; for smaller changes, the differences between individual samples of natural amber may be greater than in the case of thermal modification

Optical Methods of Methane Detection

Methane is the most frequently analyzed gas with different concentrations ranging from single ppm or ppb to 100%. There are a wide range of applications for gas sensors including urban uses, industrial uses, rural measurements, and environment monitoring. The most important applications include the measurement of anthropogenic greenhouse gases in the atmosphere and methane leak detection. In this review, we discuss common optical methods used for detecting methane such as non-dispersive infrared (NIR) technology, direct tunable diode spectroscopy (TDLS), cavity ring-down spectroscopy (CRDS), cavity-enhanced absorption spectroscopy (CEAS), lidar techniques, and laser photoacoustic spectroscopy. We also present our own designs of laser methane analyzers for various applications (DIAL, TDLS, NIR).</jats:p

Antibacterial properties of graphene and its derivatives

The work presents a literature review on the use of graphene and its derivatives as the potential protection against bacterial microflora. Addressed issues relate to an attempt to explain the mechanisms of impact of graphene and its derivatives: graphene oxide (GO) and reduced graphene oxide (rGO) on the bacterial cells. Interaction of graphene materials (G, GO, rGO) with Gram(+) and Gram(-) were compared with regard to the concentration of the preparations, the nature of the culture medium and surface of graphene deposition. Issues related to the development of reactive oxygen species (ROS) were discussed, the effect of sharp edges of GM’s (nano-knife), biofilm formation and the potential application of graphene in nanomedicine. Keywords: biomedicine, graphene, graphene oxide antibacterial effect, biofilm </jats:p