Visible Light Inactivation
Visible Light Inactivation - Related Videos
08:25
Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate
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Cited by 3 •
2022
Here, we present a protocol to inactivate pathogenic bacteria with reactive oxygen species produced during photolysis of flavin mononucleotide (FMN) under blue and violet light irradiation of low intensity. FMN photolysis is demonstrated to be a simple and safe method for sanitary processes.
03:19
Inactivation of Bacteria Using Light-Activated Flavin Mononucleotide
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2025
Source: Cheng, C., et al. Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate. J. Vis. Exp. (2022)This video demonstrates a method for evaluating the phototoxic effects of flavin mononucleotide (FMN) on pathogenic bacteria. Bacterial cultures are exposed to increasing concentrations of FMN and illuminated with visible light to generate reactive oxygen species (ROS) that damage cellular components. The surviving bacteria are then quantified to assess the...
02:23
Quantification of Light-Induced Bacterial Inactivation Through Reactive Oxygen Species Generation
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2025
Source: Cheng, C., et al. Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate. J. Vis. Exp. (2022).In this video, a buffered reaction mixture containing L-methionine, nitro blue tetrazolium (NBT), and flavin mononucleotide (FMN) is irradiated with violet light to induce reactive oxygen species (ROS) production. This leads to bacterial inactivation and the formation of spectrometrically detectable formazan.
05:57
The Synergistic Effect of Visible Light and Gentamycin on Pseudomona aeruginosa Microorganisms
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Cited by 8 •
2013
We show that a developed biomedical device involving continuous or pulsed visible laser based treatment that is combined with antibiotic treatment (gentamycin), results in a statistically significant synergistic effect leading to a reduction in the viability of P. aeruginosa PAO1, by 8 log's compared to antibiotic treatment alone.
01:58
X-Inactivation
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2019
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results. Instead, in order to avoid this potential issue, female mammalian cells inactivate nearly all the genes in one of their X chromosomes during early embryonic development. In the nuclear envelope surrounding the cell nucleus, the inactivated X chromosome...
FAQs
The selected wavelength determines how effectively the photosensitizer absorbs incident light and initiates the inactivation chemistry. A wavelength that does not support useful absorption may produce less reactive oxygen species even when the light dose is increased. For bioengineering designs, wavelength selection therefore connects the light source to the chosen photosensitizer and to the intended treatment target.
Reactive oxygen species are the immediate chemical agents generated in photodynamic treatment. They can damage membranes, proteins, nucleic acids, and other essential components. Oxygen availability therefore becomes a limiting condition: even with illumination and a photosensitizer, reduced oxygen can constrain the resulting inactivation. This makes oxygen conditions an important consideration when designing light-based treatment systems.
Effectiveness depends on the interaction among wavelength, light dose, photosensitizer concentration, oxygen availability, and the organism or material being treated. Changing any one of these conditions can alter the amount of reactive oxygen species generated or the target's susceptibility to damage. Bioengineers must therefore evaluate the treatment conditions together rather than treating light exposure as an isolated variable.
A basic design begins by identifying the microorganism, cell, or biological agent to be controlled, then selecting a photosensitizer and a compatible visible-light wavelength. The system must also establish an appropriate light dose while considering photosensitizer concentration and oxygen availability. Finally, researchers assess whether the exposure reduced viability or activity under the intended material or environmental conditions.
Bioengineering applications include antimicrobial surfaces, water-treatment systems, equipment-treatment systems, biomedical materials, and targeted approaches for controlling contamination. These settings differ in their treated materials and biological targets, but each can use the same design variables: wavelength, dose, photosensitizer concentration, and oxygen availability. The approach is especially relevant when contamination control must be integrated into engineered systems.
The principal outcomes are changes in microbial or cellular viability and activity, together with evidence that contamination has been controlled. Interpretation should be tied to the treatment conditions, including wavelength, light dose, photosensitizer concentration, and oxygen availability. Comparing outcomes across these variables helps determine whether poor performance reflects insufficient exposure, unsuitable chemistry, or differences in the treated organism or material.