Determination of the threshold dose distribution in photodynamic action from in vitro experiments

Faria, Clara Maria Gonçalves de; Inada, Natália Mayumi; Kurachi, Cristina; Bagnato, Vanderlei Salvador

doi:10.1016/j.jphotobiol.2016.06.041

Cited by 12 publications

(4 citation statements)

References 55 publications

(33 reference statements)

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“… 11 PpIX accumulation showed a decreasing pattern when the ALA concentration exceeded the optimal threshold (OPT). 22 This phenomenon may be related to pH conditions, where maintaining a pH of 7.0 to 7.6 appeared to be conducive to increasing PpIX levels within the cells. 23 , 24 Taken together, these results highlight the exceptional nanomaterial properties of ANPs as a versatile drug delivery system.…”

Section: Discussionmentioning

confidence: 99%

Effects of Photodynamic Therapy Using 5 -Aminolevulinic Acid (ALA) Loaded Acrylic Nanoparticles (ANPs) on HaCaT Cells

Ge,

Zhao,

Liu

et al. 2024

CCID

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Objective ALA-PDT (5-aminolevulinic acid photodynamic therapy) is a central modality in the treatment of skin diseases. Increasing the bioavailability of ALA remains a critical issue. With this in mind, our study explores a novel route of ALA delivery by loading acrylic nanoparticles (ANPs). Methods ALA-ANPs were synthesized by emulsion polymerisation and characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). The effects of ALA-ANPs on HaCaT cell line were evaluated, including characteristics, morphological changes, protoporphyrin IX (PpIX) fluorescence kinetics, reactive oxygen species (ROS) levels, mitochondrial membrane potential and ki67 expression in these cells. Results The ANPs had uniform sizes, smooth surfaces and excellent light transmittance, with diameters of 150–200 nm. In contrast, the ALA - ANPs had uneven surfaces and poor light transmittance, with diameters of 220–250 nm. During 12 hours of co-incubation of HaCaT cells with ALA, the intracellular accumulation of PpIX increased over time. Notably, after 6 hours of incubation, PpIX levels induced by 1.81 mg/mL ALA-ANPs exceeded those induced by 1.0 mM ALA ( p < 0.01 ). CCK-8 results showed a positive correlation between PDT-induced inhibition of HaCaT cell proliferation and ALA concentration when ALA concentration remained below 2.0 mM. Compared to the 1.0 mM ALA group, the 1.81 mg/mL ALA-ANPs group showed decreased mitochondrial membrane potential, ki67 immunofluorescence intensity and cell proliferation. In contrast, ROS levels were significantly increased in the 1.81 mg/mL ALA-ANPs group (p < 0.01). Conclusion Loading ANPs provide improved stability and potency for ALA. The ALA-ANPs-PDT approach has superior inhibitory effects on HaCaT proliferation in vitro.

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Section: Discussionmentioning

confidence: 99%

Effects of Photodynamic Therapy Using 5 -Aminolevulinic Acid (ALA) Loaded Acrylic Nanoparticles (ANPs) on HaCaT Cells

Ge,

Zhao,

Liu

et al. 2024

CCID

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“…In photodynamic therapy, the threshold dose is the amount of light required to cause irreversible cell damage. 99 In a population, the variability between individuals leads to a distribution in the threshold values which could explain the behavior seen in Figure 8. On the other hand, the same protocol had no significant impact on the viability of any of the cell lines tested, thus not allowing a median threshold dose to be estimated.…”

Section: Discussionmentioning

confidence: 93%

“…The other publications that used ICG and infrared light on cell lines found cytotoxicity but used concentrations of ICG that were much higher. [98][99] In the case of Engel et al, rather than measuring the photodynamic effect, they were interested in the toxicity of the products of the photodegradation of ICG, which was significant for RPE cells. However, in our case, there is no evidence of that occurring.…”

Section: Discussionmentioning

confidence: 99%

Pulmonary antimicrobial photodynamic therapy and the role of the lung surfactant

Kassab¹

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“…36 Despite these advantages, exist an important consideration for an effective PDT, the threshold dose. 37 On the assumption that the dominant mechanism in the PDT is type II, 25 it will exist a threshold of singlet oxygen. 38 To superated the threshold dose, effectiveness photosensitizer concentration and light exposure are necessaries.…”

Section: Literature Reviewmentioning

confidence: 99%

Theoretical evaluation of the light distribution and PDT dose for a multi-wavelength light source

Guachamin¹

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The broad absorption spectrum of Protoporphyrin IX (PpIX) allows being activated by a source with an emission spectrum in the visible region. Also, PpIX can be activated simultaneously by two or more sources whose emission spectrum overlaps with its absorption spectrum. Sources with a wide spectrum of illumination, such as lamps and Sun, have a different light-tissue interaction, and the constant monitoring of the dose of light and the total damage caused by photodynamic therapy (PDT) becomes difficult. The main objectives of this study were to simulate the distribution of light in the tissue for a multiwavelength source and determine the total theoretical photodynamic dose. This study is composed of three parts. First, photobleaching experiments of PpIX using different light sources and the development of a mathematical model was used to explain the change in PpIX concentration. Second, Monte Carlo simulation using MCX (Monte Carlo eXtreme) was performed to know the light distribution through in a human skin model. Finally, the theoretical photodynamic dose was determined using the two steps mentioned previously. The experimental results show that the decrease in the concentration of PpIX is mainly dependent on the dose of photons absorbed. Therefore, for a multi-wavelength source, the total damage is calculated by partial damages caused by each wavelength that active the PpIX. The simulation of the light distribution in the human skin phantom demonstrated that the energy fluence rate decrease as a function of the depth. The mathematical model estimates that the efficacy of PDT, where it is guaranteed there is necrosis, has a diameter and depth of about 0.3 and 0.2 mm respectively. This model can be expanded to other biological media, other photosensitizers and even to any source of illumination.

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Determination of the threshold dose distribution in photodynamic action from in vitro experiments

Cited by 12 publications

References 55 publications

Effects of Photodynamic Therapy Using 5 -Aminolevulinic Acid (ALA) Loaded Acrylic Nanoparticles (ANPs) on HaCaT Cells

Effects of Photodynamic Therapy Using 5 -Aminolevulinic Acid (ALA) Loaded Acrylic Nanoparticles (ANPs) on HaCaT Cells

Pulmonary antimicrobial photodynamic therapy and the role of the lung surfactant

Theoretical evaluation of the light distribution and PDT dose for a multi-wavelength light source

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