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Optical absorbance of the tympanic membrane in rat and human samples

Chronic infections are often connected to biofilm formation. In presence of implants, this can lead to loss of the implant. Systemic or local application of drugs is relatively ineffective in case of biofilm formation. One technique to provide antibacterial properties on demand is the antibacterial...

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Autores principales: Goblet, Madeleine, Matin, Farnaz, Lenarz, Thomas, Paasche, Gerrit
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8297804/
https://www.ncbi.nlm.nih.gov/pubmed/34293032
http://dx.doi.org/10.1371/journal.pone.0254902
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author Goblet, Madeleine
Matin, Farnaz
Lenarz, Thomas
Paasche, Gerrit
author_facet Goblet, Madeleine
Matin, Farnaz
Lenarz, Thomas
Paasche, Gerrit
author_sort Goblet, Madeleine
collection PubMed
description Chronic infections are often connected to biofilm formation. In presence of implants, this can lead to loss of the implant. Systemic or local application of drugs is relatively ineffective in case of biofilm formation. One technique to provide antibacterial properties on demand is the antibacterial photodynamic therapy (aPDT). Using this technique, these properties can be “switched on” by light illumination. In the middle ear with the semitransparent tympanic membrane, it might be possible in future to activate the antibacterial effect without opening the membrane. Therefore, we investigated the optical absorbance spectra of the tympanic membrane. Optical absorbance spectra were measured in ex vivo preparations from neonatal and adult rats with the membrane still being attached to the surrounding bony ring and four human samples. After performing area scans, the spot with the lowest absorbance being surrounded by a ring like structure with higher absorbance was chosen as region of interest for scanning wavelengths between 300 and 900 nm. Absorbance is generally higher at lower wavelengths with a local absorbance maximum at 420 nm and a weak second maximum with two neighbouring peaks at 540 / 580 nm and is significantly higher in adult rats compared to neonatal rats where about 10% of light was transmitted. The human samples show similar characteristics with a little higher absorbance. For activation of aPDT through the tympanic membrane, larger wavelengths are more promising. Whether the amount of light transmitted through the membrane would be sufficient to induce aPDT remains to be tested in further experiments.
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spelling pubmed-82978042021-07-31 Optical absorbance of the tympanic membrane in rat and human samples Goblet, Madeleine Matin, Farnaz Lenarz, Thomas Paasche, Gerrit PLoS One Research Article Chronic infections are often connected to biofilm formation. In presence of implants, this can lead to loss of the implant. Systemic or local application of drugs is relatively ineffective in case of biofilm formation. One technique to provide antibacterial properties on demand is the antibacterial photodynamic therapy (aPDT). Using this technique, these properties can be “switched on” by light illumination. In the middle ear with the semitransparent tympanic membrane, it might be possible in future to activate the antibacterial effect without opening the membrane. Therefore, we investigated the optical absorbance spectra of the tympanic membrane. Optical absorbance spectra were measured in ex vivo preparations from neonatal and adult rats with the membrane still being attached to the surrounding bony ring and four human samples. After performing area scans, the spot with the lowest absorbance being surrounded by a ring like structure with higher absorbance was chosen as region of interest for scanning wavelengths between 300 and 900 nm. Absorbance is generally higher at lower wavelengths with a local absorbance maximum at 420 nm and a weak second maximum with two neighbouring peaks at 540 / 580 nm and is significantly higher in adult rats compared to neonatal rats where about 10% of light was transmitted. The human samples show similar characteristics with a little higher absorbance. For activation of aPDT through the tympanic membrane, larger wavelengths are more promising. Whether the amount of light transmitted through the membrane would be sufficient to induce aPDT remains to be tested in further experiments. Public Library of Science 2021-07-22 /pmc/articles/PMC8297804/ /pubmed/34293032 http://dx.doi.org/10.1371/journal.pone.0254902 Text en © 2021 Goblet et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Goblet, Madeleine
Matin, Farnaz
Lenarz, Thomas
Paasche, Gerrit
Optical absorbance of the tympanic membrane in rat and human samples
title Optical absorbance of the tympanic membrane in rat and human samples
title_full Optical absorbance of the tympanic membrane in rat and human samples
title_fullStr Optical absorbance of the tympanic membrane in rat and human samples
title_full_unstemmed Optical absorbance of the tympanic membrane in rat and human samples
title_short Optical absorbance of the tympanic membrane in rat and human samples
title_sort optical absorbance of the tympanic membrane in rat and human samples
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8297804/
https://www.ncbi.nlm.nih.gov/pubmed/34293032
http://dx.doi.org/10.1371/journal.pone.0254902
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