A New Method to Test the Effectiveness of Sunscreen Ingredients in a Novel Nano-surface Skin Cell Mimic

Krishnan, Rajagopal; Elmets, Craig A.; Nordlund, Thomas M.

doi:10.1562/2006-07-05-ra-961

Cited by 3 publications

(1 citation statement)

References 22 publications

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“…Using spheres of smaller size will reduce the scattering and may obviate the need for a modified background. The weak emission of octyl methoxycinnamate between 360 and 400 nm in the nanosphere system was confirmed by using intrinsic nanosphere fluorescence as a source of excitation light (41) for cinnamate. In this case there was smaller scattering background from sphere.…”

Section: Emission Of Octyl Methoxycinnamate Adsorbed To Hacat Cells Amentioning

confidence: 86%

Fluorescence of Sunscreens Adsorbed to Dielectric Nanospheres: Parallels to Optical Behavior on HaCat Cells and Skin

Krishnan

Pradhan

Timares

et al. 2006

Photochem Photobiol

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Sunscreens applied to the skin are retained primarily in the stratum corneum, where they adsorb and act as a barrier preventing UV penetration to deeper layers. Photophysical properties of sunscreens have traditionally been studied either in solvents, which are very different from skin, or in skin or complex artificial skin systems, which are difficult to handle. The purpose of this study was to determine whether polystyrene nanospheres could serve as an improvement over solvents for evaluation of the photophysical properties of sunscreens without the presence of autofluorescence from and interactions with specific skin biomolecules. We used HaCat cells and excised skin for this comparative study with nanospheres. Fluorescence spectral properties of common hydrophobic sunscreens octyl salicylate, padimate O (2-ethylhexyl-4-dimethylaminobenzoate) and octyl methoxycinnamate adsorbed to 220 nm polystyrene spheres are similar to those of sunscreens adsorbed to HaCat cells and excised skin. Specifically, similarity in the emission peaks and their approximate positions, excitation peak positions and a measurable reduction in scattering upon sunscreen addition suggest that polystyrene nanospheres constitute a useful system to evaluate the photophysical properties of topical sunscreens and may serve as a model system for high-throughput evaluation of potential sunscreens. An unexpected result of this comparative study was the observation of an increase in a specific skin component emission caused by addition of padimate O.

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Section: Emission Of Octyl Methoxycinnamate Adsorbed To Hacat Cells Amentioning

confidence: 86%

Fluorescence of Sunscreens Adsorbed to Dielectric Nanospheres: Parallels to Optical Behavior on HaCat Cells and Skin

Krishnan

Pradhan

Timares

et al. 2006

Photochem Photobiol

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Fluorescence Dynamics of Three UV-B Sunscreens

Krishnan

Nordlund

2007

J Fluoresc

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Polarity of the surrounding medium affects the excited states of UV-B sunscreens. Therefore understanding excited state processes in a mixed polarity model system similar to skin is essential. We report the excited state lifetimes, quantum yields, radiative and non-radiative rates of three sunscreens. Among the three UV-B sunscreens studied, octyl salicylate emits from a single excited state, while padimate O and octyl methoxy cinnamate show multiple states. The radiative rates of salicylate and cinnamate are approximately constant, while that of padimate O depends strongly on solvent. The non-radiative rates of all sunscreens vary with solvent polarity. Compared to salicylate and cinnamate, padimate O is complex to analyze because of its two emission peaks and one peak's strong dependence on the dielectric constant. High absorbance, broad absorption peak with small fluorescence quantum yield, and low radiative rate make octyl methoxy cinnamate a superior UV-B sunscreen ingredient. The complexity in excited-state analysis shows that the lifetimes of the sunscreens are critical parameters, in addition to absorbance and quantum yield. Fluorescence lifetime substantiates the use of polystyrene nanospheres as a model host to study the photo-physical properties of sunscreen in a heterogeneous environment.

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Environmental Fate of Organic Sunscreens during Water Disinfection Processes: The Formation of Degradation By-Products and Their Toxicological Profiles

et al. 2022

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The development of any commercial product should also be aimed at reducing the risk associated with it, according to the safe-by-design concept; that is, risk assessment should always be at the center of the design, and the impact on human and environmental health should be assessed and eliminated during the product development phase and not afterwards. Unfortunately, even today, most operators in any production sector implement the philosophy of “risk management” or rather of managing the problem when it occurs, using spot interventions instead of changing the approach. This argument is also valid in the production of solar filters, which have reached a satisfactory degree of efficiency in the face of a substantial underestimation of the risks associated with their possible environmental fate. In fact, solar filters have been found in bathing waters and their environmental fate may depend on various factors such as the pH of the water, the presence of organic material, metal ions and light, and, above all, the chemical agents used in the disinfection of the water itself. Thus, during disinfection processes, the generation of dozens of products with a lower molecular weight and generally of an aromatic nature has been tested, where some of them did not receive an exact structural definition and a precise evaluation of their precise toxicological profile. Therefore, it is interesting to draw a complete picture of organic sunscreens and of the byproducts obtained under different conditions and their related ecotoxicological profile.

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A New Method to Test the Effectiveness of Sunscreen Ingredients in a Novel Nano-surface Skin Cell Mimic

Cited by 3 publications

References 22 publications

Fluorescence of Sunscreens Adsorbed to Dielectric Nanospheres: Parallels to Optical Behavior on HaCat Cells and Skin

Fluorescence of Sunscreens Adsorbed to Dielectric Nanospheres: Parallels to Optical Behavior on HaCat Cells and Skin

Fluorescence Dynamics of Three UV-B Sunscreens

Environmental Fate of Organic Sunscreens during Water Disinfection Processes: The Formation of Degradation By-Products and Their Toxicological Profiles

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