Identification of free radicals induced by UV irradiation in collagen water solutions

Metreveli, Nunu; Namicheishvili, L; Jariashvili, Ketevan; Dgebuadze, Marine; Chikvaidze, E; Sionkowska, Alina

doi:10.1016/j.jphotobiol.2008.06.003

Cited by 13 publications

(7 citation statements)

References 21 publications

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“…Pickled hide behaves as undyed crust which has high reflectance of the UV radiations that scatter the radiation, and hence their impact on the structure is minimal [36]. Free radicals appear in collagen water solutions under UV radiation and evoke photodegradation of the macromolecule [37]. Figure 4 illustrates the influence of tanning on the tand.…”

Section: Resultsmentioning

confidence: 99%

Influence of UV radiation on the viscoelastic properties and dynamic viscosity of bovine hide using dynamic mechanical analysis

Nalyanya

Migunde

Ngumbu

et al. 2015

J Therm Anal Calorim

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The wide range of applications of collagenbased materials has triggered research interest especially on the effect of environmental factors in that these materials are exposed to during processing and application. As the applications of these collagenous materials continue to increase such as in the field of medicine, more studies are required to gain more insight into their properties. Collagen is a natural biopolymer whose structure is sensitive to ultraviolet (UV) radiations, which alters its mechanical properties. In this study, the influence of artificial UV irradiations, wavelength 254 nm, on the viscoelastic properties and dynamic viscosity of both pickled and tanned hide was investigated by dynamic mechanical analysis. The influence of tanning on the viscoelastic properties and dynamic viscosity was also investigated. Freshly flayed bovine hide was conventionally prepared to pickling stage and split into two identical halves along the backline. One half was tanned using chromium sulfate, while the other half was left at the pickled stage. Samples of appropriate dimensions from both the pickled and tanned hides were cut and irradiated with artificial UV light for different time duration of 6-30 h. The irradiated samples were then analyzed using the DMA in the multi-frequency mode. It was found that irradiation caused an increase in the storage modulus (E 0 ) of pickled hide over the entire irradiation of 6 h followed by consistent decrease up to a duration of 30 h. Tanning caused an increase in tand that consistently decreased with the increase in the duration of irradiation. In addition, UV irradiation caused an increase in dynamic viscosity of pickled hide, but a decrease in tanned hide. The results show the predominant elastic nature of bovine hides as indicated by tand magnitudes less than a unit.

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Section: Resultsmentioning

confidence: 99%

Influence of UV radiation on the viscoelastic properties and dynamic viscosity of bovine hide using dynamic mechanical analysis

Nalyanya

Migunde

Ngumbu

et al. 2015

J Therm Anal Calorim

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“…There are many studies from different laboratories characterizing the collagen oxidative damage as a result of UV radiation 8, 11–20. The most widespread hypothesis is that collagen peptide bonds are cleaved randomly by UV without disrupting the triple helical structure 8.…”

Section: Introductionmentioning

confidence: 99%

Uv damage of collagen: Insights from model collagen peptides

et al. 2011

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Fibrils of type I collagen in the skin are exposed to ultraviolet (UV) light and there have been claims that collagen photo-degradation leads to wrinkles and may contribute to skin cancers. To understand the effects of UV radiation on collagen, type I collagen solutions were exposed to the UV-C wavelength of 254 nm for defined lengths of time at 4°C. Circular dichroism (CD) experiments show that irradiation of collagen leads to high loss of triple helical content with a new lower thermal stability peak and SDS-gel electrophoresis indicates breakdown of collagen chains. To better define the effects of UV radiation on the collagen triple-helix, the studies were extended to peptides which model the collagen sequence and conformation. CD studies showed irradiation for days led to lower magnitudes of the triple-helix maximum at 225 nm and lower thermal stabilities for two peptides containing multiple Gly-Pro-Hyp triplets. In contrast, the highest radiation exposure led to little change in the Tm values of (Gly-Pro-Pro)10 and (Ala-Hyp-Gly)10, although (Gly-Pro-Pro)10 did show a significant decrease in triple helix intensity. Mass spectroscopy indicated preferential cleavage sites within the peptides, and identification of some of the most susceptible sites of cleavage. The effect of radiation on these well defined peptides gives insight into the sequence and conformational specificity of photo-degradation of collagen.

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“…UV irradiation primarily induces the formation of free radicals, 37 which cause the destruction of substances under the action of light. Consequently, the stability of individual compounds and conjugates is associated, among other things, with their antiradical properties.…”

Section: Resultsmentioning

confidence: 99%

Chitosan‐hydroxycinnamic acid conjugates: Synthesis, photostability and phytotoxicity to seed germination of barley

Nikalaichuk

Hileuskaya

Kraskouski

et al. 2021

J of Applied Polymer Sci

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Chitosan‐caffeic and chitosan‐ferulic acid conjugates are synthesized by carbodiimide method and characterized by UV, FTIR, and NMR spectroscopy. There are two obtained forms of conjugates: freshly synthesized and reconstituted freeze‐dried. A comparative study of the stability of various conjugate forms over time and under UV irradiation has been carried out. It has been shown that the absorption intensity of an aqueous solution of the freshly synthesized chitosan‐caffeic acid conjugate decrease in ~2 times during 20 weeks of storage, while the maximum rate of intensity decrease is observed during the first 40 days. The absorption intensity of the chitosan‐ferulic acid conjugate decrease by 6–7% during the entire storage period. It has been found that freeze‐dried powders of chitosan‐caffeic and chitosan‐ferulic acid conjugates are stable for at least 1 year. It has been established that freeze‐dried chitosan‐caffeic and chitosan‐ferulic acid conjugates are more stable under UV irradiation (in 4–8 and 1.4–1.9 times, respectively) compared to freshly synthesized ones. A comparative study of the influence of conjugates on barley seedlings (Hordeum vulgare L.) growth has been carried out.

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Identification of free radicals induced by UV irradiation in collagen water solutions

Cited by 13 publications

References 21 publications

Influence of UV radiation on the viscoelastic properties and dynamic viscosity of bovine hide using dynamic mechanical analysis

Influence of UV radiation on the viscoelastic properties and dynamic viscosity of bovine hide using dynamic mechanical analysis

Uv damage of collagen: Insights from model collagen peptides

Chitosan‐hydroxycinnamic acid conjugates: Synthesis, photostability and phytotoxicity to seed germination of barley

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