Evaluation of the Practicality of Melanin as a Photodynamic-Inactivation Photosensitizer by Its Nanonization

Liu, Yicheng; Tu, Shih‐Yu; Lin, Hoang‐Yan

doi:10.2494/photopolymer.28.739

Cited by 3 publications

(2 citation statements)

References 45 publications

(43 reference statements)

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“…Although some properties and effects caused by pheomelanin nanoparticles have been investigated in previous works [1,25,38], there is not reported evidence about its inactivation action in bacteria. Due to the fact E. coli is Gram-negative, its photoinactivation is a challenging aim.…”

Section: Final Remarksmentioning

confidence: 99%

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The growth of Escherichia coli cultures under the influence of pheomelanin nanoparticles and a chelant agent in the presence of light

et al. 2022

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Growing concern of antibiotic resistance has increased research efforts to find nonspecific treatments to inhibit pathogenic microorganisms. In this regard, photodynamic inactivation is a promising method. It is based on the excitation of a photosensitizer molecule (PS) with UV-Vis radiation to produce reactive oxygen species. The high reactivity of such species nearby the PS leads to oxidation of bacterial cell walls, lipid membranes (lipid peroxidation), enzymes, and nucleic acids, eventually producing cell death. In the last decade, many studies have been carried out with different photosensitizers to suppress the growth of bacteria, fungi, viruses, and malignant tumors. Here, our main motivation is to employ pheomelanin nanoparticles as sensitizers for inhibiting the growth of the Gram-negative bacteria E. coli, exposed to blue and UVA radiation. In order to perform our experiments, we synthesized pheomelanin nanoparticles from L-DOPA and L-cysteine through an oxidation process. We carried out experiments at different particle concentrations and different energy fluences. We found that cultures exposed to UVA at 166 μg/mL and 270 J/cm2, in conjunction with ethylenediaminetetraacetic acid (EDTA) as an enhancer, decreased in the viable count 5 log10. Different reactive oxygen species (singlet oxygen, hydroxyl radicals, and peroxynitrates) were detected using different procedures. Our results suggest that the method reported here is effective against E. coli, which could encourage further investigations in other type of bacteria.

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Section: Final Remarksmentioning

confidence: 99%

“…The authors found a reduction of around 50% of viability. In another study, Yi-Cheng et al [38] investigated the effect of Sepia and synthetic melanin in Gram-positive bacteria irradiated at 660 nm, reporting non-significant response.…”

Section: Introductionmentioning

confidence: 99%

The growth of Escherichia coli cultures under the influence of pheomelanin nanoparticles and a chelant agent in the presence of light

et al. 2022

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Effect of 460 nm blue light PBM on human MeWo melanoma cells

Qin,

Yang,

Jiang

et al. 2024

Journal of Biophotonics

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Photobiomodulation (PBM) using 460 nm blue light has been shown to have an inhibitory effect on skin cancer cells. In this study, we used a continuous LED light source with a wavelength of 460 nm and designed various combinations of power density (ranging from 6.4 to 25.6 mW) and dose (ranging from 0.96 to 30.72 J/cm2) to conduct treatment experiments on MeWo cells to investigate the effects of blue light on MeWo melanoma cells. We are focusing on cell viability, cytotoxicity, mitochondrial function, oxidative stress, and apoptosis. We found that blue light inhibits these melanoma cells through oxidative stress and DNA damage, and this inhibition intensifies at higher irradiance levels. Although the cells initially attempt to resist the stress induced by the treatment, they eventually undergo apoptosis over time. These findings contribute to understanding melanoma's molecular response to blue light PBM, lay the groundwork for future clinical applications.

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Self-assembled surfactant-based nanoparticles as a platform for solubilization and enhancement of the photothermal activity of sepia melanin

Ghoubary

Fadel

Fadeel

2023

Beni-Suef Univ J Basic Appl Sci

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Background Sepia melanin (SM) is a natural photothermal biopolymer. Its biomedical applications are limited due to its poor solubility and bioavailability. This study aims to prepare a soluble formulation of sepia melanin to enhance its solubility, in turn, its bioavailability, and its use in photothermal therapy of cancer. SM was extracted from a sepia ink sac and prepared as insoluble powdered (SM) which is identified by FTIR, 1H-NMR, thermogravimetric analysis (TGA), and scanning electron microscope. SM was self-assembled using tween 80 into dispersed nanoparticles (SM-NP-Tw). The prepared SM-NP-Tw were fully characterized. The photothermal performance of SM-NP-Tw was assessed. Dark and photocytotoxicity of SM-NP-Tw was studied on HepG2 cells using two wavelengths (660 nm and 820 nm). Results The insoluble powdered (SM) exhibited a spherical nanoparticle-like shape as revealed by scanning electron microscope and was soluble only in an alkaline aqueous solution. TGA of SM showed high resistance to thermal degradation indicating good thermal stability. The prepared SM-NP-Tw exhibited a spherical shape with mean sizes of 308 ± 86 nm and a zeta potential of − 25 mv. The cell viability decreased significantly upon increasing the concentration and upon radiation at 820 nm. The results of UV–Vis spectroscopy and the photothermal performance revealed that melanin can absorb light in a wide range of wavelengths including near the IR region; thus, it can emit sufficient heat to kill cells through the photoheat conversion effects. Conclusion Sepia melanin nanoparticles self-assembled into tween-based nanostructures could be a promising natural platform for photothermal cancer therapy.

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Evaluation of the Practicality of Melanin as a Photodynamic-Inactivation Photosensitizer by Its Nanonization

Cited by 3 publications

References 45 publications

The growth of Escherichia coli cultures under the influence of pheomelanin nanoparticles and a chelant agent in the presence of light

The growth of Escherichia coli cultures under the influence of pheomelanin nanoparticles and a chelant agent in the presence of light

Effect of 460 nm blue light PBM on human MeWo melanoma cells

Self-assembled surfactant-based nanoparticles as a platform for solubilization and enhancement of the photothermal activity of sepia melanin

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