Name: LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation (Video) | JoVE Journal
Uploaded: 2025-01-24T14:30:00.000+00:00
Duration: 5 min 13 s
Description: Learn an economical LED-based method for screening photosensitizers in antibacterial photodynamic inactivation using Staphylococcus aureus. This 96-well plate technique enables high-throughput evaluation of flavylium compounds for therapeutic applications.

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5 minutes

This work was financially supported by FCT project FERMEN.TO - FERmented foods to struggle MEtabolic syNdrome. An inTegrated in vitro dynamic approach (2023.00164.RESTART). This work was supported by the Associate Laboratory for Green Chemistry - LAQV (LA/P/0008/2020 https://doi.org/10.54499/LA/P/0008/2020; UIDP/50006/2020 https://doi.org/10.54499/UIDP/50006/2020; UIDB/50006/2020 https://doi.org/10.54499/UIDB/50006/2020) which national funds finance from FCT/MCTES. P.C. thanks her PhD grant from FCT (SFRH/BD/150661/2020). Iva Fernandes acknowledges her assistant professor contract (https://doi.org/10.54499/CEECINST/00064/2021/CP2812/CT0004).

An overall description of the protocol is illustrated in Figure 1. The details of the reagents and equipment used are listed in the Table of Materials.
1. Bacterial culture preparation
<ol>
	<li>Grow S. aureus (ATCC 29213) bacteria on Mueller-Hinton agar (MH) from stock cultures. Incubate the MH plates at 37 &#176;C for 24 h prior to the assay to obtain fresh cultures.</li>
	<li>Inoculate bacteria: Collect 2-3 fresh colonies from the agar plate and dilute in 6 mL of pre-warmed phosphate-buffered saline (PBS) pH 7.4, sterile filtered.</li>
	<li>Vortex (1200 rpm) the inoculum 3-4 times to ensure proper homogenization of the sample.Withdraw 3 mL to a disposable cuvette.</li>
	<li>Measure OD600 and adjust it to 0.1 (approximately 1 x 108 CFU/mL) using PBS. 
	NOTE: The exact OD to CFU conversion can vary based on the strain of S. aureus. One can establish a standard growth curve for the specific strain and lab experimental conditions working with.</li>
</ol>
2. Photosensitizer preparation
<ol>
	<li>Stock solution: Prepare a stock solution of the compound of interest photosensitizer (see Results section for details) in an appropriate solvent (e.g., DMSO or PBS; Figure 2).</li>
	<li>Working solution: Dilute the stock solution in PBS. The use of PBS rather than bacterial culture media ensures that the components of the media do not interfere with light absorption during aPDI experiments.</li>
	<li>Vortex the sample to ensure complete homogenization. Use an ultrasonic bath if necessary to guarantee complete solubilization and achieve a clear solution (in that case, carefully control. For hydrophobic compounds, adjustment of the solvent system might be required (e.g., adding a % of DMSO or ethanol). Ensure that the effect of the solvent on cellular viability is always checked. 
	NOTE: The conditions for sonication will vary depending on the type of compound, concentration, and system solvent; shorter times (e.g., 5 min) might be sufficient for easily solubilized compounds, while longer times (20-30 min) may be required for highly hydrophobic compounds.</li>
</ol>
3. Plate setup
<ol>
	<li>Prepare two separate 96-well plates: one to undergo light exposure and another to be kept in the dark (dark control).</li>
	<li>In each of the plates, mix 100 &#181;L of the photosensitizer solution with 100 &#181;L of the bacterial suspension. Pipette up and down 5-10 times.</li>
	<li>Incubate the plates at 37 &#176;C for a pre-determined interval (in this study, a period of 30 min was used) to allow the photosensitizer to interact with the bacterial cells.</li>
</ol>
4. Irradiation
<ol>
	<li>Remove the plates from the incubator and expose one of them to the light emitted from the LED panel (the device used in this experiment consisted of a rectangular LED projector of 50W power; IP65; input voltage: AC 85-265 V), keeping the other one protected from light exposure.</li>
	<li>Place one of the plates above the LED panel. To ensure precise adjustment of the plate through several protocol repetitions, mark the edges of the 96-well plate directly on the LED surface.</li>
	<li>Expose the plate for a suitable irradiation time (in this study, a period of 15 min was used). 
	NOTE: Ensure the light dose is sufficient to activate the photosensitizer without compromising cellular viability. For that reason, light control must be included (bacteria exposed to light in the absence of photosensitizer).</li>
</ol>
5. Post-irradiation and agar plate sampling
<ol>
	<li>Use another 96-well plate to prepare the serial dilutions of the samples (controls, non-irradiated, and irradiated wells).</li>
	<li>Add 180 &#181;L of PBS/well according to the number of samples. To properly define the layout, take into consideration that a row of 6 wells is needed for the serial dilution of one sample (10-fold dilution, from 10&#8722;1 to 10&#8722;6).</li>
	<li>Aliquot 20 &#181;L from each well (from the irradiated and non-irradiated 96-well plate) to the first column of the plate previously filled up with PBS.</li>
	<li>With the multi-channel micropipette, perform a simple serial dilution from well 1 to 6 (10-1 to 10-6). NOTE: Sample homogenization is critical at this point to ensure a uniform and consistent mixture. At every dilution step, pipette up and down 5-10 times.</li>
	<li>Divide the agar plate into six equal parts, each section corresponding to one of the dilutions (see Figure 3).</li>
	<li>Aliquot 10 &#181;L from each well onto the corresponding section on the surface of the agar plate (for each sample, include at least 3 replicates). Avoid placing aliquots too close to each other. Gently transport the agar plates to the incubator and wait for 18-20 h. 
	NOTE: Take into consideration that the morphology of CFUs varies significantly depending on the bacteria species. For instance, while S. aureus colonies are relatively easy to count, P. aeruginosa tends to form more diffuse-type colonies. The number of replicates might be adjusted considering this.</li>
</ol>
6. Cellular viability determination (colony-forming units counting)
<ol>
	<li>Remove the agar plates from the incubator and select the areas suitable for cell counting. 
	NOTE: Avoid counting within sections with abundant, overlapped, and non-well-defined colonies.</li>
	<li>Within each section, count the number of colony-forming units (CFUs) and determine the average of the 3 replicates</li>
	<li>Convert the number of counted CFU to CFU/mL, multiplying the average counting by the dilution factor and splitting by the volume of culture plated in mL.</li>
</ol>
7. Data analysis
<ol>
	<li>Convert the data of CFU/mL to the logarithmic scale and represent cellular viability in log10|CFU/mL| as a function of the concentration tested.</li>
</ol>

<ol><li>Correia, J. H., Rodrigues, J. A., Pimenta, S., Dong, T., Yang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photodynamic+therapy+review%3A+principles%2C+photosensitizers%2C+applications%2C+and+future+directions%5BTitle%5D)+AND+%22Pharmaceutics%22%5BJournal%5D)">Photodynamic therapy review: principles, photosensitizers, applications, and future directions.</a> Pharmaceutics. 13 (9), 1332(2021).</li>
<li>Hamblin, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Antimicrobial+photodynamic+inactivation%3A+A+bright+new+technique+to+kill+resistant+microbes%5BTitle%5D)+AND+%22Curr+Opin+Microbiol%22%5BJournal%5D)">Antimicrobial photodynamic inactivation: A bright new technique to kill resistant microbes.</a> Curr Opin Microbiol. 33 (6), 67-73 (2016).</li>
<li>Aroso, R. T., Oliveira, S. M., Almeida, A., Carvalho, C. M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photodynamic+disinfection+and+its+role+in+controlling+infectious+diseases%5BTitle%5D)+AND+%22Photochem+Photobiol+Sci%22%5BJournal%5D)">Photodynamic disinfection and its role in controlling infectious diseases.</a> Photochem Photobiol Sci. 20 (11), 1497-1545 (2021).</li>
<li>Rapacka-Zdończyk, A., Woźniak, A., Podbielska, H., Kasprzycka, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Factors+determining+the+susceptibility+of+bacteria+to+antibacterial+photodynamic+inactivation%5BTitle%5D)+AND+%22Front+Med%22%5BJournal%5D)">Factors determining the susceptibility of bacteria to antibacterial photodynamic inactivation.</a> Front Med. 8, 733501(2021).</li>
<li>Dolmans, D. E. J. G. J., Fukumura, D., Jain, R. K. Photodynamic therapy for cancer. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aDolmans%2C+DEJGJ+%22Nat+Rev+Cancer%22">Nat Rev Cancer</a>. 3 (5), 380-387 (2003).</li>
<li>Lima, E., Reis, L. V., Silva, A. L. C., Carvalho, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photodynamic+therapy%3A+From+the+basics+to+the+current+progress+of+N-heterocyclic-bearing+dyes+as+effective+photosensitizers%5BTitle%5D)+AND+%22Molecules%22%5BJournal%5D)">Photodynamic therapy: From the basics to the current progress of N-heterocyclic-bearing dyes as effective photosensitizers.</a> Molecules. 28 (13), 5103(2023).</li>
<li>Pérez-Laguna, V., Pérez-Artiaga, L., Royo-Díaz, D., Gilaberte, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+combination+of+photodynamic+therapy+and+antimicrobial+compounds+to+treat+skin+and+mucosal+infections%3A+A+systematic+review%5BTitle%5D)+AND+%22Photochem+Photobiol+Sci%22%5BJournal%5D)">A combination of photodynamic therapy and antimicrobial compounds to treat skin and mucosal infections: A systematic review.</a> Photochem Photobiol Sci. 18 (5), 1020-1029 (2019).</li>
<li>Babilas, P., Karrer, S., Szeimies, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photodynamic+therapy+in+dermatology%3A+state-of-the-art%5BTitle%5D)+AND+%22Photodermatol+Photoimmunol+Photomed%22%5BJournal%5D)">Photodynamic therapy in dermatology: state-of-the-art.</a> Photodermatol Photoimmunol Photomed. 26 (3), 118-132 (2010).</li>
<li>Pérez-Laguna, V., Pérez-Artiaga, L., Gilaberte, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photodynamic+therapy+combined+with+antibiotics+or+antifungals+against+microorganisms+that+cause+skin+and+soft+tissue+infections%3A+a+planktonic+and+biofilm+approach+to+overcome+resistances%5BTitle%5D)+AND+%22Pharmaceutics%22%5BJournal%5D)">Photodynamic therapy combined with antibiotics or antifungals against microorganisms that cause skin and soft tissue infections: a planktonic and biofilm approach to overcome resistances.</a> Pharmaceutics. 14 (6), 1-16 (2021).</li>
<li>Almenara-Blasco, M., López-Roca, A., Pérez-Sanchez, A., Valiente, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Antimicrobial+photodynamic+therapy+for+dermatological+infections%3A+current+insights+and+future+prospects%5BTitle%5D)+AND+%22Front+Photobiol%22%5BJournal%5D)">Antimicrobial photodynamic therapy for dermatological infections: current insights and future prospects.</a> Front Photobiol. 2, 773502(2024).</li>
<li>de Oliveira, A. B., Reis, C., Soares, M. T., Batista, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photodynamic+therapy+for+treating+infected+skin+wounds%3A+a+systematic+review+and+meta-analysis+from+randomized+clinical+trials%5BTitle%5D)+AND+%22Photodiagnosis+Photodyn+Ther%22%5BJournal%5D)">Photodynamic therapy for treating infected skin wounds: a systematic review and meta-analysis from randomized clinical trials.</a> Photodiagnosis Photodyn Ther. 40 (5), 103-118 (2022).</li>
<li>Correia, P., Oliveira, S. R., Batista, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Light-activated+amino-substituted+dyes+as+dual-action+antibacterial+agents%3A+bio-efficacy+and+AFM+evaluation%5BTitle%5D)+AND+%22Dyes+Pigm%22%5BJournal%5D)">Light-activated amino-substituted dyes as dual-action antibacterial agents: bio-efficacy and AFM evaluation.</a> Dyes Pigm. 224, 111975(2024).</li>
<li>Oliveira, H., Santos, A. R., Costa, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photoactivated+cell-killing+amino-based+flavylium+compounds%5BTitle%5D)+AND+%22Sci+Rep%22%5BJournal%5D)">Photoactivated cell-killing amino-based flavylium compounds.</a> Sci Rep. 11 (1), 22005(2021).</li>
<li>Sharma, S., Singh, V., Kaur, S., Mehta, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Microbial+biofilm%3A+A+review+on+formation%2C+infection%2C+antibiotic+resistance%2C+control+measures%2C+and+innovative+treatment%5BTitle%5D)+AND+%22Microorganisms%22%5BJournal%5D)">Microbial biofilm: A review on formation, infection, antibiotic resistance, control measures, and innovative treatment.</a> Microorganisms. 11 (6), 1614(2023).</li>
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The authors have nothing to disclose.

Although this protocol serves as an initial stage testing platform, it is important to consider more meaningful testing conditions for the treatment of microbial infections in a more advanced study phase. When assessing the effectiveness of aPDI, experiments on biofilm-type bacterial organizations rather than planktonic bacteria should be conducted. Many clinical cases involve microorganisms organized in this more resistant conformation, such as chronic wounds, cystic fibrosis, and on implanted medical devices<sup class=...

Photodynamic therapy (PDT) is a minimally invasive therapeutic approach that has shown promising results in recent years, particularly in dermatological clinical treatment1. One particularly interesting area of application of this therapeutic modality is the treatment of microbial infections, a process known as antimicrobial photodynamic inactivation (aPDI)2. Although initially overlooked, mostly because of the remarkable efficiency of antibiotics, light-triggered eradication of bacterial growth underwent a renewed interest over the recent years, driven by the emergence of antimicrobial multidrug resistance (AMR) and the need to find alternative and efficient strategies to address this public-health concern3,4. Significant results can be achieved within seconds or minutes, with spatial and temporal precision offered by specifically irradiating the area of interest and the on/off feature of the procedure, respectively.
The mechanism behind the photodynamic principle relies on the combination of light-sensitive molecules (photosensitizer), molecular oxygen, and an external light source. Although these three components are harmless, when combined, they might become lethal to the target cells due to the photoactivation of the photosensitizer. Light-triggered reactions result in a massive generation of reactive oxygen species (ROS), which ultimately causes severe and irreversible damage in crucial cellular components, leading to cell death5,6. Also, the combination of aPDI with other conventional antimicrobial treatments has shown promising therapeutic outcomes, including higher treatment efficacy, reduced treatment time, and lower drug dosages7.
Moreover, the topical administration of photosensitizers (PS) in PDT allows for targeted treatment with minimal damage to surrounding tissues and low systemic effects, making it a well-appreciated option for treating superficial skin infections8. The convenience of topical treatment and the superficial nature of many skin infections and lesions make it an appealing target for PDT. Studies have supported the effectiveness of aPDI in treating burn infections, surgical wound infections, ulcerated lesions, and other superficial ailments such as acne and impetigo9,10,11.
Numerous molecules, both natural and synthetic, have been tested and proposed for aPDI. However, the use of varying and often unspecified parameters in experimental protocols makes it challenging to compare results, which affects the clarity of scientific findings. Developing simple and reproducible tests can facilitate the swift screening of numerous compounds, expediting the identification of promising candidates. Straightforward, reproducible, and cost-effective protocols are especially valuable in early-stage testing, as they enable comparison of results across different research facilities. Efficient screening processes also make it easier to explore a wider range of molecules, potentially leading to the discovery and selection of new photosensitizers for further testing in more advanced, complex, and costly methodologies.
This protocol outlines a straightforward method for evaluating the phototoxicity of potential photosensitizers on bacteria using an LED panel with a light intensity of 25 mW/cm2. A representative bacterial strain, S. aureus, was used, and the white light channel was selected, offering full coverage of the visible spectrum. The procedure involved a 30 min pre-incubation period followed by a 15 min exposure to light (22.5 J/cm2). While the results are based on these specific experimental conditions, they can be tailored according to individual protocols. It is essential to clearly define these settings and include them in the procedural description.

<table><tbody><tr><td>Cary 60 UV-Vis Spectrophotometer</td><td>Agilent</td><td>G6860A</td><td></td></tr><tr><td>Dimethyl Sulfoxide</td><td>Sigma-Aldrich</td><td>D8418</td><td></td></tr><tr><td>Disposable cuvettes PMMA</td><td>BRAND GMBH + CO KG</td><td>759030</td><td></td></tr><tr><td>Eppendorfs (500 mL)</td><td>Fisher Scientific</td><td>15625367</td><td></td></tr><tr><td>Falcon tubes (15 mL)</td><td>Corning</td><td>430791</td><td></td></tr><tr><td>Falcon tubes (50 mL)</td><td>Corning</td><td>430291</td><td></td></tr><tr><td>LED panel IP65 50W</td><td></td><td></td><td></td></tr><tr><td>Micropippete (100 uL)</td><td>Transferpette S</td><td>705874</td><td></td></tr><tr><td>Micropippete (1000 uL)</td><td>Transferpette S</td><td>705880</td><td></td></tr><tr><td>Mueller Hinton agar&amp;nbsp;</td><td>Oxoid</td><td>CM0405</td><td></td></tr><tr><td>Multichannel pippete 12-channel</td><td>Transferpette S</td><td></td><td></td></tr><tr><td>Nunc MicroWell 96-Well Microplates</td><td>Thermo Scientific</td><td>260844</td><td></td></tr><tr><td>Phospate Buffered Saline tablets pH 7.4</td><td>Panreac Applichem</td><td>A9177</td><td></td></tr><tr><td>Serological Pipets (10 mL)</td><td>Thermo Scientific</td><td>170356N</td><td></td></tr><tr><td>Serological Pipets (5 mL)</td><td>Thermo Scientific</td><td>170366N</td><td></td></tr><tr><td>Tissue Culture Dish</td><td>TPP Techno Plastic Products AG</td><td>93150</td><td></td></tr></tbody></table>

led-based in vitro screening for assessing photoactivable molecules in bacterial photodynamic inactivation

LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation

The rise of multi-drug-resistant infections and the lack of new antibiotic classes have renewed interest in alternative therapies like photodynamic inactivation of bacteria (aPDI). This process involves the administration of a photosensitizer (PS) activated by a suitable visible light source, producing exacerbated levels of reactive oxygen species (ROS) that damage crucial cellular biomolecules, ultimately causing bacterial cell death. It is crucial to create standardized, easy-to-use, and reproducible initial tests to assess and compare the effectiveness of light-induced phototoxicity of potential photosensitizers. This study introduces a simple and efficient in vitro technique for assessing photodynamic activity against planktonic bacterial cells. By employing a 96-well microplate format along with a large LED panel, the system facilitates the systematic evaluation of various compounds. Such a configuration allows for high-throughput screening of potential photosensitizers in a controlled and consistent environment, simplifying the process of identifying promising candidates for further development. This flexible platform serves as an important step in advancing the development of innovative photodynamic therapies for managing antibiotic-resistant infections.

Amino-based flavylium compounds (Figure 2): 7-diethylamino-4′-dimethylaminoflavylium (7NEt24′NMe2), 7-diethylamino-2-(dimethylaminostyryl)-1-benzopyrylium (7NEt2st4′NMe2), 7-diethylamino-4′-aminoflavylium(7NEt24′NH2) and 7-diethylamino-4′-hydroxyflavylium (7NEt24′OH), whose light responsive nature was previously discussed12,13, were incubated with S. aur...

This protocol describes a straightforward and economical method for evaluating the effectiveness of potential photosensitizers in antibacterial photodynamic inactivation (aPDI), using a 96-well plate format combined with an LED panel light source. This approach enables the simultaneous testing of multiple experimental conditions, including different concentrations, compounds, and bacterial strains.

The rise of multi-drug-resistant infections and the lack of new antibiotic classes have renewed interest in alternative therapies like photodynamic ...

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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...

Inactivation of Bacteria Using Light-Activated Flavin Mononucleotide

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.

Quantification of Light-Induced Bacterial Inactivation Through Reactive Oxygen Species Generation

Source: Zhao, K., et al. An In Vitro Model to Study the Effect of 5-Aminolevulinic Acid-mediated Photodynamic Therapy on Staphylococcus aureus Biofilm. J. Vis. Exp. (2018)The video demonstrates a photodynamic therapy protocol to assess antibacterial effects on Gram-positive bacterial biofilms. Biofilms are divided into four groups: two receive a photosensitizer precursor, and two receive a buffer. All are incubated in the dark, followed by red light exposure to one precursor-treated group and...

Light-Activated Treatment of Bacterial Biofilms Using a Photosensitizer Precursor

Infections caused by multidrug-resistant (MDR) bacterial strains have emerged as a serious threat to public health, necessitating the development of alternative therapeutics. We present a protocol to evaluate the effectiveness of antimicrobial blue light (aBL) therapy for MDR Acinetobacter baumannii infections in mouse burns by using bioluminescence imaging.

In Vivo Investigation of Antimicrobial Blue Light Therapy for Multidrug-resistant Acinetobacter baumannii Burn Infections Using Bioluminescence Imaging

This manuscript describes a protocol to study the antimicrobial effect of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) on a Staphylococcus aureus biofilm. This protocol can be used to develop an in vitro model to study the treatment of bacterial biofilms with PDT in the future.

An In Vitro Model to Study the Effect of 5-Aminolevulinic Acid-mediated Photodynamic Therapy on Staphylococcus aureus Biofilm

Photodynamic therapy (PDT) is a medical procedure that involves incubation of an exogenously applied photosensitizer (PS) followed by visible light photoactivation to induce apoptosis. We present an in vitro PDT protocol designed to simulate PDT that may be used to study differences in PS incubation and light treatment parameters.

An In Vitro Approach to Photodynamic Therapy

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.

Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5&#8242;-Phosphate

The growing incidence of drug-resistant Candida albicans is a serious health issue worldwide. Antimicrobial photodynamic therapy (aPDT) may offer a strategy to fight against drug-resistant fungal infections. The present protocol describes Rose bengal-mediated aPDT efficacy on a multidrug-resistant C. albicans strain in vitro.

Rose Bengal-Mediated Photodynamic Therapy to Inhibit Candida albicans

Here, we describe a novel, simple, and low-cost device to successfully perform in vitro photodynamic therapy (PDT) assays using two-dimensional HeLa cell culture and verteporfin as a photosensitizer.

An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model

This protocol presents a set of experiments adopted for the evaluation of photoswitchable anticancer peptides, that can be used in the preclinical screening of such compounds. This includes cytotoxicity assessment in 2D and 3D cell cultures, the evaluation of ex vivo (model tissue) photoisomerization efficiency, and in vivo efficacy.

In Vitro and In Vivo Evaluation of Photocontrolled Biologically Active Compounds - Potential Drug Candidates for Cancer Photopharmacology

This manuscript presents a novel, innovative 3D-printed illumination device for studying Rose Bengal-mediated photodynamic therapy in vitro.

Development of an Innovative LED-based Illumination Device for In Vitro Application of Photodynamic Therapy with Rose Bengal

Learn an economical LED-based method for screening photosensitizers in antibacterial photodynamic inactivation using Staphylococcus aureus. This 96-well plate technique enables high-throughput evaluation of flavylium compounds for therapeutic applications.

LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation

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