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Abstract(s)
A criação de efeitos de transparência em tecidos biológicos é uma área recente de investigação que tem por objetivo superar o forte espalhamento da luz que é característico dos tecidos naturais para poder otimizar a aplicação de procedimentos clínicos de diagnóstico e de tratamento que utilizem a luz. Se durante os últimos 30 anos a investigação nesta área foi intensa, com a descoberta de certos agentes inócuos e capazes de criar transparência em tecidos, há ainda outros produtos naturais que poderão ser potenciais agentes de transparência e que precisam de ser estudados. As características desejáveis para que um determinado agente possa criar transparência em tecidos são conhecidas e apenas com a verificação da existência de tais características num determinado agente, este pode ser aceite e utilizado na criação de transparência em tecidos biológicos. O presente estudo foi realizado com o objetivo de caracterizar certos agentes de transparência já reconhecidos e alguns óleos de produtos naturais que são vendidos para aplicações cosméticas e culinárias e que apresentam um elevado índice de refração a 589,6 nm. A caracterização destes líquidos consistiu na medição dos seus índices de refração a vários comprimentos de onda para criar a sua curva de dispersão entre 200 e 1000 nm, na medição dos seus espetros de transmitância colimada para identificar as suas bandas de absorção e na realização de tratamentos de tecido músculo-esquelético com cada um dos líquidos para avaliar se criam transparência ou não. Em termos de dispersões, verificou-se que todos os óleos apresentavam elevados valores em todo o espetro, sendo sempres superiores aos obtidos para os agentes de transparência já reconhecidos que foram também estudados. No entanto, durante a avaliação dos espetros medidos dos líquidos em estudo verificou-se que todos os óleos apresentam as suas bandas de absorção na zona do ultravioleta, sendo a absorção determinada de 100 % e com uma largura espetral significativa. Tal facto é um sério inconveniente para a criação de transparência em tecidos biológicos. Como resultado dos tratamentos aplicados com estes óleos em amostras de músculo, verificou-se que alguns deles podem ser úteis se combinados com certos agentes de transparência, uma vez que poderão induzir uma rápida desidratação do tecido, aumentar a permeabilidade à difusão do agente de transparência, ou até mesmo dissociar proteínas, que é um dos mecanismos que contribui para a criação de transparência nos tecidos biológicos.
The creation of transparency effects in biological tissues is a recent research field that aims to overcome the strong light scattering that is characteristic in natural tissues to optimize the application of clinical diagnostic and treatment procedures that use light. Although during the last 30 years, research in this area has been intense, with the discovery of certain innocuous agents that are capable of creating transparency in tissues, there are still other natural products that could be potential clearing agents and that need to be studied. The desirable characteristics for a given agent to create transparency in tissues are known and only with the verification that such agent has those characteristics, it can be accepted and used to create transparency in biological tissues. The present study was carried out with the objective of characterizing certain already recognized transparency agents and some oils from natural products that are sold for cosmetic and culinary applications and that have a high refractive index at 589.6 nm. The characterization of these liquids consisted of measuring their refractive indices at various wavelengths to create their dispersion curve between 200 and 1000 nm, measuring their collimated transmittance spectra to identify their absorption bands and performing treatments on musculoskeletal tissue samples with each of the liquids to assess whether they create transparency or not. In terms of dispersions, it was found that all oils had high values across the entire spectrum, always being higher than those obtained for the already recognized transparency agents that were also studied. However, during the evaluation of the measured spectra of the liquids under study, it was found that all the oils present their absorption bands in the ultraviolet range, with the evaluated absorption being 100 % within a significant spectral width. This fact is a serious inconvenience for creating transparency in biological tissues. As a result of the treatments applied with these oils in muscle samples, it was found that some of them can be useful if combined with certain transparency agents, since they can induce a rapid dehydration of the tissue, increase the permeability to the diffusion of the transparency agent, or even dissociating proteins, which is one of the mechanisms that contributes to the creation of transparency in biological tissues.
The creation of transparency effects in biological tissues is a recent research field that aims to overcome the strong light scattering that is characteristic in natural tissues to optimize the application of clinical diagnostic and treatment procedures that use light. Although during the last 30 years, research in this area has been intense, with the discovery of certain innocuous agents that are capable of creating transparency in tissues, there are still other natural products that could be potential clearing agents and that need to be studied. The desirable characteristics for a given agent to create transparency in tissues are known and only with the verification that such agent has those characteristics, it can be accepted and used to create transparency in biological tissues. The present study was carried out with the objective of characterizing certain already recognized transparency agents and some oils from natural products that are sold for cosmetic and culinary applications and that have a high refractive index at 589.6 nm. The characterization of these liquids consisted of measuring their refractive indices at various wavelengths to create their dispersion curve between 200 and 1000 nm, measuring their collimated transmittance spectra to identify their absorption bands and performing treatments on musculoskeletal tissue samples with each of the liquids to assess whether they create transparency or not. In terms of dispersions, it was found that all oils had high values across the entire spectrum, always being higher than those obtained for the already recognized transparency agents that were also studied. However, during the evaluation of the measured spectra of the liquids under study, it was found that all the oils present their absorption bands in the ultraviolet range, with the evaluated absorption being 100 % within a significant spectral width. This fact is a serious inconvenience for creating transparency in biological tissues. As a result of the treatments applied with these oils in muscle samples, it was found that some of them can be useful if combined with certain transparency agents, since they can induce a rapid dehydration of the tissue, increase the permeability to the diffusion of the transparency agent, or even dissociating proteins, which is one of the mechanisms that contributes to the creation of transparency in biological tissues.
Description
Keywords
Tecido músculo-esquelético Agentes de transparência Transparência ótica Índices de refração Curvas de dispersão Bandas de absorção Transmitância colimada Eficiência de transparência Musculoskeletal tissue Optical clearing agents Optical transparency Refractive indices Dispersion curves Absorption bands Collimated transmittance Transparency efficiency