Assessing UV Damage and Antioxidant Influence on Human Hair Using a Combination of Spectroscopic, Thermal and Physical Measurements
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Presented by: Yingxia He
UV destruction of human hair has been well documented in the literature. The impact on hair cuticle and cortex causes surface impairment and protein loss. Methodologies applied to evaluate UV damage of hair include SEM, protein analysis, ESR, Raman, FTIR, color and tensile measurement. The level of UV damage is directly linked to exposure dosage, hair type and condition, and preventing treatment, such as utilizing antioxidant. The aim of this study is to use a combined approach of Fluorescence Spectroscopy with DCFH probe to detect reactive oxygen species, FTIR to evaluate cystine oxidation, DSC to evaluate structural changes within hair cortex, tensile and cyclic fatigue methods to assess the mechanical impact on hair.
In this study, medium brown Caucasian hair treated with aqueous solution or hair conditioner with and without antioxidant was subjected to different exposure levels of UV or UV/Ozone damage. UV damage was generated with Q-Sun 3100 or Atlas Ci3000+ Xenon weather-Ometer. Ozone damage was created with NO2/NO/O3 generator M713. The integrity of hair before and after induced damage was assessed with DCFH-DA assay, FTIR, DSC, tensile and cyclic fatigue methods.
DCFH-DA assay was conducted with two different protocols: one set of hair was treated with 0.0% and 1.0% antioxidant aqueous solutions as leave-on treatment, while the other set of hair was treated with hair conditioners containing 0.0% and 1.0% active antioxidant as rinse-off application. After respective treatment, hair samples were subjected to 10J/cm2 of UVA irradiation, then DCFH-DA assay was performed to produce fluorescence to be recorded with a microplate reader. For leave-on treatment, fluorescence intensity of unprotected hair increased by 147% after UV exposure, which indicated the formation of reactive oxygen species from UV exposed hair, whereas fluorescence intensity of hair treated with 1.0% antioxidant solution reduced 65% in comparison with the unprotected hair. For rinse-off application, fluorescence intensity of hair treated with 1.0% antioxidant formulation decreased by 50% versus that of unprotected hair. The data suggested that antioxidant effectively reduced oxidative stress of hair against UV exposure.
To investigate UV dosage effect, hair tresses treated with conditioner with and without antioxidant were exposed to 120 hours of UV (18J/cm2.hr) and evaluated at 30 hours intervals. For unprotected hair, increased cysteic acid peak intensity and decreased denaturation temperature were proportionally linked to UV dosage. Cyclic fatigue measurements concluded that extended UV exposure significantly diminished the integrity of hair. After 120 hours of UV exposure, fatigue cycles decreased by 50% for unprotected hair, while antioxidant treated hair improved fatigue cycles by 32% versus unprotected hair.
Hair samples were also exposed to UV/Ozone pollution for two hours after treated with 0.0% and 1.0% antioxidant aqueous solution. The procedure was repeated for 12 cycles to study cumulative detrimental impact. Then hair samples were assessed via FTIR and tensile measurement. In comparison with before UV/Ozone exposure, cysteic acid peak of damaged hair increased significantly, coupled with decreased tensile break stress. However, with antioxidant protection, lower amount of cysteine was oxidized to cysteic acid, the results also agreed with higher tensile strength for the protected hair.
The study results confirm that different measurements can provide different evidence on the damage effect of UV to human hair. The intensity of fluorescence from DCFH-DA assay reflects quantity of reactive oxygen species due to photo oxidation of hair; the damage can also be detected by FTIR using intensity of cysteic acid peak as a marker. DSC data validates that UV diminishes cross-link density of hair matrix; denaturation temperature of UV damaged hair decreases significantly versus that of undamaged hair. Tensile and cyclic fatigue data are consistent with results from DCFH-DA, FTIR and DSC methods. In conclusion, internal damage weakens physical strength of hair, the collective impact can be best verified with a combined approach of employing various spectroscopic and physical measurement techniques.
In this study, medium brown Caucasian hair treated with aqueous solution or hair conditioner with and without antioxidant was subjected to different exposure levels of UV or UV/Ozone damage. UV damage was generated with Q-Sun 3100 or Atlas Ci3000+ Xenon weather-Ometer. Ozone damage was created with NO2/NO/O3 generator M713. The integrity of hair before and after induced damage was assessed with DCFH-DA assay, FTIR, DSC, tensile and cyclic fatigue methods.
DCFH-DA assay was conducted with two different protocols: one set of hair was treated with 0.0% and 1.0% antioxidant aqueous solutions as leave-on treatment, while the other set of hair was treated with hair conditioners containing 0.0% and 1.0% active antioxidant as rinse-off application. After respective treatment, hair samples were subjected to 10J/cm2 of UVA irradiation, then DCFH-DA assay was performed to produce fluorescence to be recorded with a microplate reader. For leave-on treatment, fluorescence intensity of unprotected hair increased by 147% after UV exposure, which indicated the formation of reactive oxygen species from UV exposed hair, whereas fluorescence intensity of hair treated with 1.0% antioxidant solution reduced 65% in comparison with the unprotected hair. For rinse-off application, fluorescence intensity of hair treated with 1.0% antioxidant formulation decreased by 50% versus that of unprotected hair. The data suggested that antioxidant effectively reduced oxidative stress of hair against UV exposure.
To investigate UV dosage effect, hair tresses treated with conditioner with and without antioxidant were exposed to 120 hours of UV (18J/cm2.hr) and evaluated at 30 hours intervals. For unprotected hair, increased cysteic acid peak intensity and decreased denaturation temperature were proportionally linked to UV dosage. Cyclic fatigue measurements concluded that extended UV exposure significantly diminished the integrity of hair. After 120 hours of UV exposure, fatigue cycles decreased by 50% for unprotected hair, while antioxidant treated hair improved fatigue cycles by 32% versus unprotected hair.
Hair samples were also exposed to UV/Ozone pollution for two hours after treated with 0.0% and 1.0% antioxidant aqueous solution. The procedure was repeated for 12 cycles to study cumulative detrimental impact. Then hair samples were assessed via FTIR and tensile measurement. In comparison with before UV/Ozone exposure, cysteic acid peak of damaged hair increased significantly, coupled with decreased tensile break stress. However, with antioxidant protection, lower amount of cysteine was oxidized to cysteic acid, the results also agreed with higher tensile strength for the protected hair.
The study results confirm that different measurements can provide different evidence on the damage effect of UV to human hair. The intensity of fluorescence from DCFH-DA assay reflects quantity of reactive oxygen species due to photo oxidation of hair; the damage can also be detected by FTIR using intensity of cysteic acid peak as a marker. DSC data validates that UV diminishes cross-link density of hair matrix; denaturation temperature of UV damaged hair decreases significantly versus that of undamaged hair. Tensile and cyclic fatigue data are consistent with results from DCFH-DA, FTIR and DSC methods. In conclusion, internal damage weakens physical strength of hair, the collective impact can be best verified with a combined approach of employing various spectroscopic and physical measurement techniques.