We thank Arthur Henrique Gomes de Oliveira and Lucas Julian Cruz Gomes for helping with the filming process. This project was supported by the Brazilian Research Council (CNPq, grant numbers 400953/2016-1-404286/2021-6) and Funda&#231;&#227;o Arauc&#225;ria-PPSUS 2020/2021 (SUS2020131000003). This study was also financed in part by Coordena&#231;&#227;o de Aperfei&#231;oamento de Pessoal de N&#237;vel Superior-Brasil (CAPES)-Finance Code 001.

NOTE: See the Table of Materials for details related to all materials, reagents, and software used in this protocol.
1. Device construction
<ol>
	<li>Saw 3 mm thickn medium-density fiberboards (MDF) to obtain pieces with the dimensions shown in Figure 1A. 
	NOTE: Use the vector file (Supplemental File 1) for computer numerical control (CNC) cutting.</li>
	<li>Build two boxes with the following dimensions (length x width x height ): 330 mm x 235 mm x 225 mm for the bigger boxes, and 300 mm x 220 mm x 150 m for the smaller boxes (Figure 1B).</li>
	<li>Drill the back of the bigger box to install a barrel jack connector. Drill the top of the bigger box andk the top and bottom of the smaller box to provide a passage for electric cables (Figure 1C).</li>
	<li>Paint all the internal surfaces with black ink to promote homogeneous light incidence (Figure 1D).</li>
	<li>Attach, in parallel, three LED tapes with 10 LEDs each at the upper interior surface of the smaller box (Figure 1E).</li>
	<li>Install a brightness sensor at the center of the bottom interior surface of the smaller box (Figure 1F).</li>
	<li>Print the structure of the control unit (Figure 1G) using the 3D printing file (Supplemental File 2).</li>
	<li>Install all the components (power button, potentiometers, time/start touchpad, LEDs, brightness sensor, LCD, buzzer, and power supply) at the ports of an ESP32 control board mounted at the control unit interior (Figure 2).</li>
	<li>Upload the programming code (Supplemental File 3, Supplemental File 4, and Supplemental File 5) and run a test to check that all the connections are working (Figure 1H).</li>
	<li>Assemble the boxes and fix them together to avoid gaps, and consequently external light interference and emitted light loss. Attach the mounted control unit to the drilled area at the top of the prototype (Figure 1I).</li>
	<li>Fix a front door of the same material and 330 mm x 225 mm (length x width) dimensions on the bigger box with two small hinges. Also, attach velcro tapes sideways to the bigger box to reinforce the prototype closure (Figure 1J). Install a handle to manipulate the front door of the equipment.</li>
	<li>Attach four rubber foot pads at the bottom of the prototype to ensure more stability during the operations (Figure 1K).</li>
</ol>
2. Cell lines: cultivation, seeding, and treatment
<ol>
	<li>Chemicals
	<ol>
		<li>Dissolve the porphyrin in dimethyl sulfoxide (DMSO) to achieve a concentration of 100 mM. 
		CAUTION: DMSO must be manipulated carefully (handling with the use of personal protective equipment and in a ventilated area). Manipulate both stock and diluted solutions carefully to avoid excessive light exposure.</li>
	</ol>
	</li>
	<li>Cell lines
	<ol>
		<li>Cultivate the HeLa cell line in Dulbecco&#39;s Modified Eagle&#39;s Medium (DMEM) low-glucose medium supplemented with 10% fetal bovine serum and 1% gentamicin.</li>
		<li>Keep the culture flasks in a 5% CO2 cell culture incubator at 37 &#176;C.</li>
		<li>Manage and inspect the cells until they reach 80%-90% confluence.</li>
	</ol>
	</li>
	<li>Seeding process
	<ol>
		<li>Remove the culture medium from the flask.</li>
		<li>Wash the cell monolayer with PBS.</li>
		<li>Detach the confluent cell culture with trypsin-EDTA (0.5%) 1x for 5 min at 37 &#176;C. Stop the action of trypsin by resuspending the cells with culture medium supplemented with 10% fetal bovine serum and 1% gentamicin.</li>
		<li>Count the resuspended cells with a hemocytometer and seed them into a 96-well plate at 2.0 &#215; 104 cells/well.</li>
		<li>Prepare two plates for dark and light conditions.</li>
		<li>Incubate the plates for 24 h for cell attachment.</li>
	</ol>
	</li>
	<li>Treatment process
	<ol>
		<li>Remove the medium from both 96-well plates.</li>
		<li>Treat the cells with 100 &#181;L of increasing concentrations of verteporfin (0.045 to 24 &#181;M, serial dilution).</li>
		<li>Incubate the cells with drug treatment for 24 h to allow verteporfin internalization.</li>
		<li>After 24 h, discard the medium containing the drug, wash the monolayer of cells with PBS (100 &#181;L), and add drug-free medium (100 &#181;L).</li>
		<li>Cover one microplate with aluminum foil to protect it from light exposure and incubate it for 24 h. This plate will provide control data for PDT results (dark condition). The other microplate will be utilized on the light exposure condition in the device.</li>
	</ol>
	</li>
</ol>
3. Device operation
<ol>
	<li>Plug the PDT device into the electrical outlet and turn it on by pressing the power button.</li>
	<li>Place the other microplate (light condition) into the PDT device and close the equipment by fastening the front door with the velcro tapes.</li>
	<li>Use the potentiometers to adjust the RGB configuration (a RGB 255, 255, 255 experiment here) and set the color of light emission. 
	NOTE: Each RGB combination has a specific emission spectrum, which must be adjusted for experiments with different photosensitizers and, consequently, different absorbance curves.</li>
	<li>Press the (+)/(-) touchpad to adjust the time configuration (a 60 min experiment here) and set the duration of the assay. 
	NOTE: The time configuration, in association with the irradiance value, will determine the fluence of the process-the light dose applied in the assay.</li>
	<li>Check the setup information at the display.</li>
	<li>Press the Start button to initiate the assay. Ensure that a one-beep buzzer is heard at the beginning of the assay.</li>
	<li>In the course of the experiment, observe real-time information on the display, such as irradiance and time left.</li>
	<li>Do not open the front door or change any configuration during the PDT assay.</li>
	<li>At the end of the assay, wait for a four-beep buzzer and for the electronic system to turn all the LEDs off. Observe a Finished message and the final amount of energy expended-fluence-during the experiment in the display. 
	NOTE: The fluence final value is calculated using equation (1): 
	<img alt="Equation 1" src="/files/ftp_upload/64391/64391eq01.jpg" style="margin: auto;" /> (1) 
	Where F&#160;equals to J/cm2 and I&#160;equals to mW/cm2 or mJ/s&#183;cm2. The irradiance value considers the potency of the LEDs (emitting source) and the uniformly irradiated area of the dark chamber (660 cm2) (equation [2]): 
	<img alt="Equation 2" src="/files/ftp_upload/64391/64391eq02.jpg" style="margin: auto;" /> (2) 
	The theorical irradiance value is shown on the device display throughout the entire PDT assay. At the end of the operation, use equation (3) to calculate the fluence: 
	Fluence (F) = irradiance (I, constant value) &#215; operation time (s) (3)</li>
</ol>
4. Cell viability assay
<ol>
	<li>After the PDT assay, cover the microplate that was exposed to light and incubate for 24 h.</li>
	<li>After the incubation period, remove the culture medium from both plates, wash the monolayer of cells with PBS (100 &#181;L), and add MTT solution (0.5 mg/ml, 100 &#181;L). Incubate both plates-dark and light conditions-for 4 h to allow formazan crystal formation.</li>
	<li>Remove the MTT solution carefully and dissolve the purple crystals with a DMSO/ethanol (1:1) solution.</li>
	<li>After complete dissolution of the crystals, carry out the absorbance measurement using a microplate reader at 595 nm. 
	NOTE: The device can be used in other important experiments such as ROS-mediated cell death triggered by photosensitizers after light exposure by flow cytometry30.</li>
</ol>

<ol>
	<li>Ferlay, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=International+agency+for+research+on+cancer.">International agency for research on cancer.</a> Global Cancer Observatory: Cancer Today. 23 (7), 323-326 (2018).</li><li>Gottesman, M. M., Fojo, T., Bates, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multidrug+resistance+in+cancer:+role+of+Atp-dependent+transporters.">Multidrug resistance in cancer: role of Atp-dependent transporters.</a> Nature Reviews Cancer. 2 (1), 48-58 (2002).</li><li>Szakacs, G., Paterson, J. K., Ludwig, J. A., Boothe-Genthe, C., Gottesman, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+multidrug+resistance+in+cancer.">Targeting multidrug resistance in cancer.</a> Nature Reviews Drug Discovery. 5 (3), 219-234 (2006).</li><li>Ackroyd, R., Kelty, C., Brown, N., Reed, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+history+of+photodetection+and+photodynamic+therapy.">The history of photodetection and photodynamic therapy.</a> Photochemistry and Photobiology. 74 (5), 656-669 (2001).</li><li>Hamblin, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+therapy+for+cancer:+what's+past+is+prologue.">Photodynamic therapy for cancer: what's past is prologue.</a> Photochemistry and Photobiology. 96 (3), 506-516 (2020).</li><li>Barr, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+contrasting+mechanisms+of+colonic+collagen+damage+between+photodynamic+therapy+and+thermal+injury.">The contrasting mechanisms of colonic collagen damage between photodynamic therapy and thermal injury.</a> Photochem Photobiol. 46 (5), 795-800 (1987).</li><li>Algorri, J. F., Ochoa, M., Rold&#225;n-Varona, P., Rodr&#237;guez-Cobo, L., L&#243;pez-Higuera, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+therapy:+A+compendium+of+latest+reviews.">Photodynamic therapy: A compendium of latest reviews.</a> Cancers. 13 (17), 4447 (2021).</li><li>Aniogo, E. C., Plackal, B., George, B. P. A., Abrahamse, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+photodynamic+therapy+on+multidrug+resistant+breast+cancer.">The role of photodynamic therapy on multidrug resistant breast cancer.</a> Cancer Cell International. 19, 91 (2019).</li><li>Spring, B. Q., Rizvi, I., Xu, N., Hasan, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+photodynamic+therapy+in+overcoming+cancer+drug+resistance.">The role of photodynamic therapy in overcoming cancer drug resistance.</a> Photochemical &amp; Photobiological Sciences. 14 (8), 1476-1491 (2015).</li><li>Dougherty, T. J., Grindey, G. B., Fiel, R., Weishaupt, K. R., Boyle, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoradiation+therapy.+II.+Cure+of+animal+tumors+with+hematoporphyrin+and+light.">Photoradiation therapy. II. Cure of animal tumors with hematoporphyrin and light.</a> Journal of the National Cancer Institute. 55 (1), 115-121 (1975).</li><li>Etcheverry, M. E., Pasquale, M. A., Garavaglia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+therapy+of+HeLa+cell+cultures+by+using+LED+or+laser+sources.">Photodynamic therapy of HeLa cell cultures by using LED or laser sources.</a> Journal of Photochemistry and Photobiology B: Biology. 160, 271-277 (2016).</li><li>Guo, Q., Dong, B., Nan, F., Guan, D., Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=5-Aminolevulinic+acid+photodynamic+therapy+in+human+cervical+cancer+via+the+activation+of+microRNA-143+and+suppression+of+the+Bcl-2/Bax+signaling+pathway.">5-Aminolevulinic acid photodynamic therapy in human cervical cancer via the activation of microRNA-143 and suppression of the Bcl-2/Bax signaling pathway.</a> Molecular Medicine Reports. 14 (1), 544-550 (2016).</li><li>Mroz, P., Yaroslavsky, A., Kharkwal, G. B., Hamblin, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+death+pathways+in+photodynamic+therapy+of+cancer.">Cell death pathways in photodynamic therapy of cancer.</a> Cancers. 3 (2), 2516-2539 (2011).</li><li>Mahalingam, S. M., Ordaz, J. D., Low, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+of+a+photosensitizer+to+the+mitochondrion+enhances+the+potency+of+photodynamic+therapy.">Targeting of a photosensitizer to the mitochondrion enhances the potency of photodynamic therapy.</a> ACS Omega. 3 (6), 6066-6074 (2018).</li><li>Granville, D. J., Levy, J. G., Hunt, D. W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+treatment+with+benzoporphyrin+derivative+monoacid+ring+A+produces+protein+tyrosine+phosphorylation+events+and+DNA+fragmentation+in+murine+P815+cells.">Photodynamic treatment with benzoporphyrin derivative monoacid ring A produces protein tyrosine phosphorylation events and DNA fragmentation in murine P815 cells.</a> Photochemistry and Photobiology. 67 (3), 358-362 (1998).</li><li>Castano, A. P., Demidova, T. N., Hamblin, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+in+photodynamic+therapy:+part+two+-+cellular+signaling,+cell+metabolism+and+modes+of+cell+death.">Mechanisms in photodynamic therapy: part two - cellular signaling, cell metabolism and modes of cell death.</a> Photodiagnosis Photodynamic Therapy. 2 (1), 1-23 (2014).</li><li>Detty, M. R., Gibson, S. L., Wagner, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+clinical+and+preclinical+photosensitizers+for+use+in+photodynamic+therapy.">Current clinical and preclinical photosensitizers for use in photodynamic therapy.</a> Journal of Medicinal Chemistry. 47 (16), 3897-3915 (2004).</li><li>Allison, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+therapy:+oncologic+horizons.">Photodynamic therapy: oncologic horizons.</a> Future Oncology. 10 (1), 123-142 (2014).</li><li>Chepurna, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+therapy+with+laser+scanning+mode+of+tumor+irradiation.">Photodynamic therapy with laser scanning mode of tumor irradiation.</a> Optical Fibers and Their Applications 2015. 9816, 323-326 (2015).</li><li>Huang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+progress+in+clinical+photodynamic+therapy.">A review of progress in clinical photodynamic therapy.</a> Technology in Cancer Research and Treatment. 4 (3), 283-293 (2005).</li><li>Chepurna, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LED-based+portable+light+source+for+photodynamic+therapy.">LED-based portable light source for photodynamic therapy.</a> Optics in Health Care and Biomedical Optics. 11190, 109-115 (2019).</li><li>Hasson, O., Wishkerman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CultureLED:+A+3D+printer-based+LED+illumination+cultivation+system+for+multi-well+culture+plates.">CultureLED: A 3D printer-based LED illumination cultivation system for multi-well culture plates.</a> HardwareX. 12, 00323 (2022).</li><li>Wu, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localised+light+delivery+on+melanoma+cells+using+optical+microneedles.">Localised light delivery on melanoma cells using optical microneedles.</a> Biomedical Optics Express. 13 (2), 1045-1060 (2022).</li><li>Erkiert-Polguj, A., Halbina, A., Polak-Pacholczyk, I., Rotsztejn, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-emitting+diodes+in+photodynamic+therapy+in+non-melanoma+skin+cancers-own+observations+and+literature+review.">Light-emitting diodes in photodynamic therapy in non-melanoma skin cancers-own observations and literature review.</a> Journal of Cosmetic and Laser Therapy. 18 (2), 105-110 (2016).</li><li>Neupane, J., Ghimire, S., Shakya, S., Chaudhary, L., Shrivastava, V. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+light+emitting+diodes+in+the+photodynamic+therapy+of+rheumatoid+arthritis.">Effect of light emitting diodes in the photodynamic therapy of rheumatoid arthritis.</a> Photodiagnosis and Photodynamic Therapy. 7 (1), 44-49 (2010).</li><li>Lins, E. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+785-nm+laser+diode-based+system+for+standardization+of+cell+culture+irradiation.">A novel 785-nm laser diode-based system for standardization of cell culture irradiation.</a> Photomedicine and Laser Surgery. 31 (10), 466-473 (2013).</li><li>Hopkins, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+In+vitro+cell+irradiation+protocol+for+testing+photopharmaceuticals+and+the+effect+of+blue,+green,+and+red+light+on+human+cancer+cell+lines.">An In vitro cell irradiation protocol for testing photopharmaceuticals and the effect of blue, green, and red light on human cancer cell lines.</a> Photochemical and Photobiological Sciences. 15 (5), 644-653 (2016).</li><li>Zhang, K., Waguespack, M., Kercher, E. M., Spring, B. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+automated+and+stable+LED+array+illumination+system+for+multiwell+plate+cell+culture+photodynamic+therapy+experiments.">An automated and stable LED array illumination system for multiwell plate cell culture photodynamic therapy experiments.</a> Research Square. , 1-18 (2022).</li><li>G&#225;lvez, E. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+and+evaluation+of+the+operational+characteristics+of+a+new+photodynamic+therapy+device.">Analysis and evaluation of the operational characteristics of a new photodynamic therapy device.</a> Photodiagnosis and Photodynamic Therapy. 37, 102719 (2022).</li><li>Bretin, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photodynamic+therapy+activity+of+new+human+colorectal+cancer.">Photodynamic therapy activity of new human colorectal cancer.</a> Cancers. 11 (10), 1474 (2019).</li><li>. T. SketchUp Available from: <a target="_blank" href="https://www.sketchup.com/">https://www.sketchup.com/</a> (2022)</li><li>LCDR PhotoDynamic Therapy (PDT) Equipment Repository. GitHub, Inc Available from: <a target="_blank" href="https://github.com/PhotoDynamicTherapy">https://github.com/PhotoDynamicTherapy</a> (2022)</li><li>W3C CSS Color Module Level 3. W3C, Inc Available from: <a target="_blank" href="https://www.w3.org/TR/css-color-3/#SRGB">https://www.w3.org/TR/css-color-3/#SRGB</a> (2022)</li></ol>

The authors declare no competing interests.

The final PhotoACT device was convenient to construct with commercially available, low-cost components at a total cost of less than $50. Additional advantages include low maintenance demands, the capacity to irradiate multiple types of culture plates, the simultaneous use of up to four units per assay, low weight (2 kg)/size (44 cm3) that allows portability, accurate and reproducible irradiation (data not shown), and a user-friendly and simple setup interface that does not require connection to computers or ot...

Among the most lethal noncommunicable diseases, cancer represents a global leading cause of premature death. It accounted for nearly 10 million deaths in 2020, representing about one in six deaths worldwide1. Additionally, the multidrug resistance (MDR) phenomenon represents a tremendous public health threat, as approved chemotherapeutic protocols fail to reach remission stages for this clinical condition2. Cancer cells can develop resistance to chemotherapy through several mechanisms; however, the overexpression of some ATP-binding cassette (ABC) transporters - ATP-dependent efflux pumps - is considered the main cause of MDR development within a tumor microenvironment3. In addition to MDR, other cancer complications, such as recurrence and metastasis, reinforce the urgent demand to develop and improve therapeutic approaches to overcome this oncological challenge.
The curative utilization of light has been practiced for centuries4, and photodynamic therapy (PDT) represents a clinically approved therapeutic approach for solid tumors. PDT combines the administration of a photosensitizer (PS) followed by light irradiation to generate reactive oxygen species (ROS) to exert selective cytotoxicity in tumor cells. This therapeutic approach is superior to conventional methods, including surgery, radiation, and chemotherapy5; it is a minimally invasive technique showing lower cytotoxicity in connective tissues6. The light application and PS accumulation directly in the tumor or its microenvironment ensure precise targeting and, consequently, minor, undesirable systemic side effects7 and the possibility of repeated treatment at the same site. Moreover, the cost is lower than that of other approaches. Owing to its promising features, PDT can be considered an appropriate option for both single, especially in the case of inoperable tumors, or adjuvant cancer treatment7, and represents an alternative for MDR related to chemotherapy8,9.
The first report showing a high objective response rate using PDT was described in 1975 in a mouse and rat model10. Since then, studies have been conducted using PDT with positive outcomes7 both in vivo and in vitro with human tumor cell lines in 2D cell culture11,12. Considering the broad applicability of clinically approved PS, regardless of their specific accumulation pathways and wavelength ranges of absorption peaks, the general process is as follows: (i) PS uptake, (ii) peaking of PS concentration at the tumor or its microenvironment, (iii) light application, (iv) PS-light interaction, (v) transfer of PS excited-state energy to either tissue substrate or surrounding oxygen molecules, (vi) ROS production involving singlet oxygen or superoxide anion, (vii) tumor cell death via, essentially, necrosis or apoptosis (direct death), autophagy (cytoprotective mechanism), tissue ischemia (vascular damage), immune modulation, or an overlap of these mechanisms7. In this final stage, the activation of a specific cell death pathway depends on many factors, such as cell characteristics, experimental design and, most importantly, PS intracellular localization and PDT-related targeted damage13.
Verteporfin is a second-generation PS, approved by regulatory agencies for clinical use in Norway and China to treat age-related macular degeneration7. After dose delivery, this prodrug was reported to partially accumulate in mitochondria14 and induce cellular protein tyrosine phosphorylation and DNA fragmentation, leading to tumor cell apoptosis15,16. After 24 h incubation for verteporfin internalization, a PDT protocol using a 690 nm wavelength setup is recommended to achieve effective levels of electromagnetic radiation transfer to adjacent molecules7,17.
Regarding the light source for PDT, the classical diode laser systems are usually expensive, technically complicated, oversized, and thus unportable18,19. As a consequence of its single-wavelength profile, which can also be observed in LED-based PDT equipment, the demand for independent units for each photosensitizer application makes the utilization of diode laser systems even more complex and economically unfeasible20,21. Therefore, the utilization of LED machinery is considered the most promising alternative to solve not only costs22 and maintenance issues, but also to provide high power output and less harmful23 and wider illuminating capability24,25,26,27.
Despite the potential contribution that LED-based equipment can offer to PDT experiments28, most commercial options still possess drawbacks such as a lack of portability, high cost, and complex construction projects and operation29. The main objective of this work was to offer a simple and reliable tool for in vitro PDT assays. This paper describes PhotoACT, an in-house-built LED-based PDT device, which is inexpensive, user-friendly, and portable. As a proof of concept, this device is shown to enhance the cytotoxicity of verteporfin in a 2D cell culture model and, therefore, can be used as a research tool in PDT experiments.

<table><tbody><tr><td>0.5% Trypsin-EDTA (10x)</td><td>Gibco</td><td>15400054</td><td>Mammalian cell culture dissociation reagent</td></tr><tr><td>3D printer</td><td>Flashforge</td><td></td><td>Finder model</td></tr><tr><td>96-well plates</td><td></td><td></td><td>Non-sterile, polystyrene, and high-binding surface plates with flat bottom wells used for 2D cell culture</td></tr><tr><td>Arduino</td><td></td><td></td><td></td></tr><tr><td>Brightness sensor</td><td></td><td></td><td>TSL2561 model with 0.1-40.000+ lux detection levels and I2C interface</td></tr><tr><td>Buttons</td><td></td><td></td><td></td></tr><tr><td>Buzzer</td><td></td><td></td><td></td></tr><tr><td>Cell culture Flasks</td><td></td><td></td><td>Sterile, polystyrene, rectangular bottom flask with Tissue Culture (TC)-treated surface, canted neck and vent cap (sizes)</td></tr><tr><td>Centrifuge Tubes</td><td></td><td></td><td>Sterile, polypropylene tubes with 15/50 mL capacity used for cell culture dilution at seeding step of the assay</td></tr><tr><td>CO&lt;sub&gt;2&lt;/sub&gt; Incubator</td><td></td><td></td><td></td></tr><tr><td>Controller board</td><td></td><td></td><td>ESP32</td></tr><tr><td>Design Software</td><td>Trimble</td><td></td><td>SketchUp</td></tr><tr><td>DMEM High Glucose</td><td>Gibco</td><td>11965092</td><td>DMEM (Dulbecco&#039;s Modified Eagle Medium) is a widely used basal medium for supporting the growth of many different mammalian cells.</td></tr><tr><td>DMSO</td><td>Sigma-Aldrich</td><td>D4540-500ML</td><td>Dimethyl sulfoxide, &amp;ge;99.5% (GC), suitable for plant cell culture</td></tr><tr><td>Fetal Bovine Serum&amp;nbsp;</td><td>Gibco</td><td>12657029</td><td>FBS provides the best value by delivering consistency of cell growth over time and passages.</td></tr><tr><td>Gentamicin (50 mg/mL)</td><td>Gibco</td><td>15750060</td><td>Water-soluble antibiotic drug originally purified from the fungus&amp;nbsp;Micromonospora purpurea. Gentamicin acts by preventing cell culture contamination</td></tr><tr><td>Hemocytometer</td><td></td><td></td><td>Neubauer patterned chamber used for cell counting at seeding step of the assay</td></tr><tr><td>Inverted Laboratory Microscope</td><td>Leica</td><td></td><td>DM IL LED</td></tr><tr><td>Laminar Flow Hood</td><td></td><td></td><td>Cabin designed to protect the working environment from contaminants by maintaining a constant, unidirectional flow of HEPA-filtered air over the work area. Used at several steps of cell cultivation and treatment procedures</td></tr><tr><td>LCD display</td><td></td><td></td><td></td></tr><tr><td>LED RGB WS2812</td><td></td><td></td><td>5050 RGB SMD model with a built-in processor. Tape with 30 LEDs, 1 meter length and 9 watts</td></tr><tr><td>MDF fiberboards</td><td></td><td></td><td>3mm thickness medium-density fiberboards</td></tr><tr><td>Microcentrifuge Tubes</td><td></td><td></td><td>Sterile, polypropylene tubes with safety lid and 1.5/2.0 mL capacity. Convenient tools for manipulating small volumes at treatment step of the assay</td></tr><tr><td>Microplate reader</td><td>ThermoFischer</td><td></td><td>Multiskan FC Microplate Photometer designed to detect a broad wavelength range of absorbance (340-850 nm). The equipment was used to evaluate cell viability after MTT incubation.</td></tr><tr><td>MTT Reagent</td><td>Invitrogen</td><td>M6494</td><td>3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Used for cell viability assays</td></tr><tr><td>Operational System</td><td>Real Time Engineers ltd.</td><td></td><td>FreeRTOS</td></tr><tr><td>P10 micripipette</td><td></td><td></td><td>Non-electronic, single-channel, 1-10 &amp;mu;L capacity</td></tr><tr><td>P1000 micropipette</td><td></td><td></td><td>Non-electronic, single-channel, 10-1000 &amp;mu;L capacity</td></tr><tr><td>P200 micropipette</td><td></td><td></td><td>Non-electronic, single-channel, 20-200 &amp;mu;L capacity</td></tr><tr><td>PDT Equipment</td><td>LumaCare</td><td></td><td>Model LC-122</td></tr><tr><td>Phosphate-Buffered Saline pH 7.4</td><td>Gibco</td><td>10010031</td><td>Balanced salt formulation used for washing cells during cultivation and assay procedures</td></tr><tr><td>Potentiometers</td><td></td><td></td><td></td></tr><tr><td>Tips</td><td></td><td></td><td>Non-sterile, universal fit, 10/200/1000 &amp;mu;L maximum volumes</td></tr><tr><td>Verteporfin</td><td>Sigma-Aldrich</td><td>SML0534-5MG</td><td>Verteporfin, &amp;ge;94% (HPLC)</td></tr></tbody></table>

an in-house-built and light-emitting-diode-based photodynamic therapy device for enhancing verteporfin cytotoxicity in a 2d cell culture model

This paper describes a novel, simple, and low-cost device to perform in vitro photodynamic therapy (PDT) assays, named the PhotoACT. The device was built using a set of conventional programmable light-emitting diodes (LEDs), a liquid crystal display (LCD) module, and a light sensor connected to a commercial microcontroller board. The box-based structure of the prototype was made with medium-density fiberboards (MDFs). The internal compartment can simultaneously allocate four cell culture multiwell microplates.
As a proof of concept, we studied the cytotoxic effect of the photosensitizer (PS) verteporfin against the HeLa cell line in two-dimensional (2D) culture. HeLa cells were treated with increasing concentrations of verteporfin for 24 h. The drug-containing supernatant medium was discarded, the adherent cells were washed with phosphate-buffered saline (PBS), and drug-free medium was added. In this study, the effect of verteporfin on cells was examined either without light exposure or after exposure for 1 h to light using red-green-blue (RGB) values of 255, 255, and 255 (average fluence of 49.1 &#177; 0.6 J/cm2). After 24 h, the cell viability was assessed by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay.
Experimental results showed that exposure of cells treated with verteporfin to the light from the device enhances the drug&#39;s cytotoxic effect via a mechanism mediated by reactive oxygen species (ROS). In addition, the use of the prototype described in this work was validated by comparing the results with a commercial PDT device. Thus, this LED-based photodynamic therapy prototype represents a good alternative for in vitro studies of PDT.

The final PDT device, named the PhotoACT, included a dark chamber to allocate up to four multiwell microplates, with its upper interior surface equipped with a set of 30 scattered LEDs programmed to emit distinct spectrums of visible light (Figure 3 and Supplemental File 6). The device was built using two associated boxes: an internal box designed as a dark chamber for the PDT assays, and an external box to cover the internal chamber and hold the control unit (<strong class=...

Watch this Scientific Journal Video about An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model at JoVE.com

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

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.

This paper describes a novel, simple, and low-cost device to perform in vitro photodynamic therapy (PDT) assays, named the PhotoACT. The device was built ...

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Research

JoVE Journal

Biochemistry

3.0K Views.  Federal University of Parana. Fotodynamische therapie, PDT, biedt verschillende voordelen voor de behandeling van kanker, en de werkzaamheid ervan hangt af van een lichtbron om een fotosensitizer te activeren. Hoewel recente ontwikkelingen in het veld, is er een gebrek aan toegang tot een duur en reproduceerbaar apparaat voor PTD voor in vitro modellen. Om aan deze vraag te voldoen, beschrijft dit werk een nieuw, eenvoudig en goedkoop apparaat om PDT-testen uit te voeren op celculturen, genaamd PhotoAct.Om de bouw ...

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

Anticancer Efficacy of Photodynamic Therapy with Lung Cancer-Targeted Nanoparticles

Photodynamic therapy (PDT) is a non-invasive and non-surgical method representing an attractive alternative choice for lung cancer treatment. Photosensitizers selectively accumulate in tumor tissue and lead to tumor cell death in the presence of oxygen and the proper wavelength of light.
To increase the therapeutic effect of PDT, we developed both photosensitizer- and anticancer agent-loaded lung cancer-targeted nanoparticles. Both enhanced permeability and retention (EPR) effect-based passive targeting and hyaluronic-acid-CD44 interaction-based active targeting were applied. CD44 is a well-known hyaluronic acid receptor that is often introduced as a biomarker of non-small cell lung cancer. 
In addition, a combination of PDT and chemotherapy is adopted in the present study. This combination concept may increase anticancer therapeutic effects and reduce adverse reactions. 
We chose hypocrellin B (HB) as a novel photosensitizer in this study. It has been reported that HB causes higher anticancer efficacy of PDT compared to hematoporphyrin derivatives1. Paclitaxel was selected as the anticancer drug since it has proven to be a potential treatment for lung cancer2. 
The antitumor efficacies of photosensitizer (HB) solution, photosensitizer encapsulated hyaluronic acid-ceramide nanoparticles (HB-NPs), and both photosensitizer- and anticancer agent (paclitaxel)-encapsulated hyaluronic acid-ceramide nanoparticles (HB-P-NPs) after PDT were compared both in vitro and in vivo. The in vitro phototoxicity in A549 (human lung adenocarcinoma) cells and the in vivo antitumor efficacy in A549 tumor-bearing mice were evaluated.
The HB-P-NP treatment group showed the most effective anticancer effect after PDT. In conclusion, the HB-P-NPs prepared in the present study represent a potential and novel photosensitizer delivery system in treating lung cancer with PDT.

Photodynamic therapy (PDT) is an alternative choice for lung cancer treatment. To increase the therapeutic effect of PDT, lung cancer-targeted nanoparticles combined with chemotherapy were developed. Both in vitro and in vivo anticancer efficacies of PDT with prepared nanoparticles were evaluated.

Photodynamic therapy (PDT) is a non-invasive and non-surgical method representing an attractive alternative choice for lung cancer treatment. ...

Cancer Research

Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers

In this article a method for the fabrication and reproducible in-vitro evaluation of conducting polymer nanoparticles blended with fullerene as the next generation photosensitizers for Photodynamic Therapy (PDT) is reported. The nanoparticles are formed by hydrophobic interaction of the semiconducting polymer MEH-PPV (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) with the fullerene PCBM (phenyl-C61-butyric acid methyl ester) in the presence of a non-compatible solvent. MEH-PPV has a high extinction coefficient that leads to high rates of triplet formation, and efficient charge and energy transfer to the fullerene PCBM. The latter processes enhance the efficiency of the PDT system through fullerene assisted triplet and radical formation, and ultrafast deactivation of MEH-PPV excited stated. The results reported here show that this nanoparticle PDT sensitizing system is highly effective and shows unexpected specificity to cancer cell lines.

This protocol describes a method for the fabrication of conducting polymer nanoparticles blended with fullerene. These nanoparticles were investigated for their potential use as a next generation photosensitizers for Photodynamic Therapy (PDT).

In this article a method for the fabrication and reproducible in-vitro evaluation of conducting polymer nanoparticles blended with fullerene as the next ...

Chemistry

One Minute, Sub-One-Watt Photothermal Tumor Ablation Using Porphysomes, Intrinsic Multifunctional Nanovesicles

We recently developed porphysomes as intrinsically multifunctional nanovesicles. A photosensitizer, pyropheophorbide &alpha;, was conjugated to a phospholipid and then self-assembled to liposome-like spherical vesicles. Due to the extremely high density of porphyrin in the porphyrin-lipid bilayer, porphysomes generated large extinction coefficients, structure-dependent fluorescence self-quenching, and excellent photothermal efficacy. In our formulation, porphysomes were synthesized using high pressure extrusion, and displayed a mean particle size around 120 nm. Twenty-four hr post-intravenous injection of porphysomes, the local temperature of the tumor increased from 30 &deg;C to 62 &deg;C rapidly upon one minute exposure of 750 mW (1.18 W/cm2), 671 nm laser irradiation. Following the complete thermal ablation of the tumor, eschars formed and healed within 2 weeks, while in the control groups the tumors continued to grow and all reached the defined end point within 3 weeks. These data show how porphysomes can be used as potent photothermal therapy (PTT) agents.

We developed novel intrinsic multifunctional nanovesicles called porphysomes, which have structure-dependent fluorescence self-quenching and unique photothermal properties, thus functioning as potent photothermal therapy agents. We formulated porphysomes using high pressure extrusion and investigated their photothermal therapy efficacy in a xenograft tumor model.

We recently developed porphysomes as intrinsically multifunctional nanovesicles. A photosensitizer, pyropheophorbide &alpha;, was conjugated to a ...

Bioengineering

5-Aminolevulinic Acid-mediated Photodynamic Therapy on Primary Bone Tumor and Bone Metastases Cell Lines

Bone metastases are associated with poor prognosis and low quality of life for the affected patients. Photodynamic therapy (PDT) emerges as a noninvasive therapy that can target local metastatic bone lesions. This paper presents an in vitro method to study the PDT effect in adherent cell lines. To this end, we demonstrate a step-by-step approach to subject both primary (giant cell bone tumor) and human bone metastatic cancer cell lines (derived from a primary invasive ductal breast carcinoma and renal carcinoma) to 5-aminolevulinic acid (5-ALA)-mediated PDT. 
After 24 h post 5-ALA-PDT irradiation (blue light-wavelength 436 nm), the therapeutic effect was assessed in terms of cell migration potential, viability, apoptotic features, and cellular growth arrest (senescence). Post 5-ALA-PDT irradiation, musculoskeletal-derived cell lines respond differently to the same doses and exposure of PDT. Depending on the extent of cellular damage triggered by PDT exposure, two different cell fates-apoptosis and senescence were noted. Variable sensitivity to PDT therapy among different bone cancer cell lines provides useful information for selecting more appropriate PDT settings in clinical settings. This protocol is designed to exemplify the use of PDT in the context of musculoskeletal neoplastic cell lines. It may be adjusted to investigate the therapeutic effect of PDT on various cancer cell lines and various photosensitizers and light sources.

This protocol presents a step-by-step methodological approach of exposing bone metastatic cells lines and primary bone tumors to 5-aminolevulinic acid-mediated photodynamic therapy (PDT). The effects on cell migration potential/invasiveness, viability, apoptosis, and senescence potential are also analyzed following PDT exposure.

Bone metastases are associated with poor prognosis and low quality of life for the affected patients. Photodynamic therapy (PDT) emerges as a noninvasive ...

Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro

In recent years, there has been the difficulty in finding more effective therapies against cancer with less systemic side effects. Therefore Photodynamic Therapy is a novel approach for a more tumor selective treatment.
Photodynamic Therapy (PDT) that makes use of a nontoxic photosensitizer (PS), which, upon activation with light of a specific wavelength in the presence of oxygen, generates oxygen radicals that elicit a cytotoxic response1. Despite its approval almost twenty years ago by the FDA, PDT is nowadays only used to treat a limited number of cancer types (skin, bladder) and nononcological diseases (psoriasis, actinic keratosis)2.
The major advantage of the use of PDT is the ability to perform a local treatment, which prevents systemic side effects. Moreover, it allows the treatment of tumors at delicate sites (e.g. around nerves or blood vessels). Here, an intraoperative application of PDT is considered in osteosarcoma (OS), a tumor of the bone, to target primary tumor satellites left behind in tumor surrounding tissue after surgical tumor resection. The treatment aims at decreasing the number of recurrences and at reducing the risk for (postoperative) metastasis.
In the present study, we present in vitro PDT procedures to establish the optimal PDT settings for effective treatment of widely used OS cell lines that are used to reproduce the human disease in well established intratibial OS mouse models. The uptake of the PS mTHPC was examined with a spectrophotometer and phototoxicity was provoked with laser light excitation of mTHPC at 652 nm to induce cell death assessed with a WST-1 assay and by the counting of surviving cells. The established techniques enable us to define the optimal PDT settings for future studies in animal models. They are an easy and quick tool for the evaluation of the efficacy of PDT in vitro before an application in vivo.

Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro

The protocol reported here allows the evaluation of the efficacy of photodynamic therapy (PDT) in cell lines and the optimization of the PDT settings before applying the therapy in animal models.

In recent years, there has been the difficulty in finding more effective therapies against cancer with less systemic side effects. Therefore Photodynamic ...

Medicine

Selective Cell Elimination from Mixed 3D Culture Using a Near Infrared Photoimmunotherapy Technique

Recent developments in tissue engineering offer innovative solutions for many diseases. For example, tissue engineering using induced pluripotent stem cell (iPS) emerged as a new method in regenerative medicine. Although this tissue regeneration is promising, contamination with unwanted cells during tissue cultures is a major concern. Moreover, there is a safety concern regarding tumorigenicity after transplantation. Therefore, there is an urgent need for eliminating specific cells without damaging other cells that need to be protected, especially in established tissue. Here, we present a method for specific cell elimination from a mixed 3D cell culture in vitro with near infrared photoimmunotherapy (NIR-PIT) without damaging non-targeted cells. This technique enables the elimination of specific cells from mixed cell cultures or tissues.

Eliminating specific cells without damaging other cells is extremely difficult, especially in established tissue, yet there is an urgent need for a cell elimination method in the tissue engineering field. Here, we present a method for specific cell elimination from a mixed 3D cell culture using near infrared photoimmunotherapy (NIR-PIT).

Recent developments in tissue engineering offer innovative solutions for many diseases. For example, tissue engineering using induced pluripotent stem ...

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.

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 ...

An In Vitro Approach to Photodynamic Therapy

Photodynamic therapy (PDT) is a medical procedure that involves incubation of an exogenously applied photosensitizer (PS) followed by visible light photoactivation to induce cell apoptosis. The Federal Drug Administration has approved PDT for the treatment of actinic keratosis, and clinical guidelines recommend PDT as a treatment for certain non-melanoma skin cancers and acne vulgaris. PDT is an advantageous therapeutic modality as it is low cost, non-invasive, and associated with minimal adverse events and scaring. In the first step of PDT, a PS is applied and allowed to accumulate intracellularly. Subsequent light irradiation induces reactive oxygen species formation, which may ultimately lead to cell apoptosis, membrane disruption, mitochondrial damage, immune modulation, keratinocyte proliferation, and collagen turnover. Herein, we present an in vitro method to study PDT in an adherent cell line. This treatment protocol is designed to simulate PDT and may be adjusted to studying the use of PDT with various cell lines, photosensitizers, incubation temperatures, or photoactivation wavelengths. Squamous cell carcinoma cells were incubated with 0, 0.5, 1.0, and 2 mM 5-aminolevulinic acid (5-ALA) for 30 min and photoactivated with 417 nm blue light for 1,000 s. The primary outcome measure was apoptosis and necrosis, as measured by annexin-V and 7-aminoactinomycin D flow cytometry. There was a dose-dependent increase in cell apoptosis following thirty-minute incubation of 5-ALA. To achieve high inter-test validity, it is important to maintain consistent incubation and light parameters when performing in vitro PDT experiments. PDT is a useful clinical procedure and in vitro research may allow for the development of novel PSs, optimization of protocols, and new indications for PDT.

An In Vitro Approach to Photodynamic Therapy

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.

Photodynamic therapy (PDT) is a medical procedure that involves incubation of an exogenously applied photosensitizer (PS) followed by visible light ...

Rose Bengal-Mediated Photodynamic Therapy to Inhibit Candida albicans

Invasive Candida albicans infection is a significant opportunistic fungal infection in humans because it is one of the most common colonizers of the gut, mouth, vagina, and skin. Despite the availability of antifungal medication, the mortality rate of invasive candidiasis remains ~50%. Unfortunately, the incidence of drug-resistant C. albicans is increasing globally. Antimicrobial photodynamic therapy (aPDT) may offer an alternative or adjuvant treatment to inhibit C. albicans biofilm formation and overcome drug resistance. Rose bengal (RB)-mediated aPDT has shown effective cell killing of bacteria and C. albicans. In this study, the efficacy of RB-aPDT on multidrug-resistant C. albicans is described. A homemade green light-emitting diode (LED) light source is designed to align with the center of a well of a 96-well plate. The yeasts were incubated in the wells with different concentrations of RB and illuminated with varying fluences of green light. The killing effects were analyzed by the plate dilution method. With an optimal combination of light and RB, 3-log growth inhibition was achieved. It was concluded that RB-aPDT might potentially inhibit drug-resistant C. albicans.

Rose Bengal-Mediated Photodynamic Therapy to Inhibit Candida albicans

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.

Invasive Candida albicans infection is a significant opportunistic fungal infection in humans because it is one of the most common colonizers of the gut, ...

Immunology and Infection

In Vitro Phototoxicity Assay: A PDT-based Method to Evaluate the Phototoxic Potential of a Photosensitizer in Lung Cancer Cells

Source: Chang, J. E., et al. <a href="https://www.jove.com/v/54865/anticancer-efficacy-photodynamic-therapy-with-lung-cancer-targeted">Anticancer Efficacy of Photodynamic Therapy with Lung Cancer-Targeted Nanoparticles.</a>&#160;J. Vis. Exp.&#160;(2016).
Photodynamic therapy (PDT) is a non-invasive and non-surgical method for lung cancer treatment. Photosensitizers selectively accumulate in tumor tissue and lead to tumor cell death in the presence of oxygen and the proper wavelength of light. In this protocol video, PDT-based method is used to evaluate the phototoxic potential of a potential photosensitizer in lung cancer cells.

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

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