Faculty Publications

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Subject: search.filters.subject.UV absorption

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    Hydroxyapatite—a promising sunscreen filter
    (Springer, 2020) Pal, A.; Hadagalli, K.; Bhat, P.; Goel, V.; Mandal, S.
    Exposure to ultraviolet (UV) radiation has been known to cause skin cancer, erythema, and sunburn. Continuous efforts have been made to make sunscreens more efficient and non-toxic. Inorganic sunscreens like TiO2 and ZnO are continued to be used for a few decades, and they are efficient in giving protection against harmful UV radiation, but they are photochemically active as well. They generate free radicals upon irradiation, which leads to reactive oxygen species (ROS) generation which is harmful to the human skin. Hydroxyapatite (HA) is a biocompatible material as it has a composition the same as the mineral content of the human bone; therefore, it is suitable for the dermatological application. Though HA itself does not provide protection against UV, studies on doped HA with various ions showed excellent performance. Pure HA absorbs only between 200 and 340 nm, with an intense band below 247 nm. HA doped with bivalent Zn2+, Fe2+, and trivalent Fe3+ and Cr3+, showed absorbance in the entire UV region. TiO2 provides absorbance in the entire UV range, while ZnO does so only in UVA. Compared to HA (refractive index, n = 1.6), TiO2 (n = 2.6) and ZnO (n = 1.9) have higher refractive index, which gives unwanted whitening effect. Additional properties can be brought in HA composites by adding material while retaining their individual properties. As HA is not photocatalytic, it does not lead to a generation of free radicals. This paper throws light on several aspects of HA-based sunscreen filters as an emerging future cosmetic material, and brief analysis and conclusions. © 2019, Australian Ceramic Society.
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    Structural, compositional and spectral investigation of prawn exoskeleton nanocomposite: UV protection from mycosporine-like amino acids
    (Elsevier Ltd, 2020) Hadagalli, K.; Kumar, R.; Mandal, S.; Basu, B.
    The present work explores the use of marine resourced prawn exoskeleton/shell as a new class of naturally occurring composite containing UV absorbing proteins. Mycosporine-like amino acids with a central aromatic ring in the exoskeleton/shell of naturally occurring prawns (Fenneropenaeus Indicus) offer excellent UV protection. The architecture of shell composite constitutes a matrix of chitin-proteins with distinct reinforcements such as spherical calcites (CaCO3), microscopic proteins, and traces of hydroxides/oxides of magnesium. The presence of tryptophan, phenylalanine, and tyrosine, forming the basic building blocks of mycosporines, is confirmed by structural, compositional, and microscopic studies on prawn shells. The UV spectroscopic signatures at 290 and 320 nm provides strong evidence for the highest UV absorption. UV absorption attributes to the presence of mycosporine-like amino acids. Hence, the current exploration of naturally occurring prawn shells directs towards an additive-free sunscreen filter without the generation of detrimental free radicals. © 2020 Elsevier B.V.
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    Effect of Fe3+ substitution on the structural modification and band structure modulated UV absorption of hydroxyapatite
    (Blackwell Publishing Ltd, 2021) Hadagalli, K.; Shenoy, S.; Shakya, K.R.; Manjunath, G.; Tarafder, K.; Mandal, S.; Basu, B.
    The effect of Fe3+ ionic substitution in hydroxyapatite (Ca10-xFex(PO4)6(OH)2) was studied using structural modifications, resulting in an improvement in UV absorption through a tailored optical band structure. Ca2+ of HA being larger compared to Fe3+ contributes to the shrinkage of the lattice. Undoped HA has a peak at 1085 cm?1 (?3 PO43?) which is shifted to 1033 cm?1 for Fe-HA, because of the perturbation in HA structure. An improvement of UV absorption in the entire UVA and UVB range with an increase in Fe content because of a decrease in bandgap from 5.9 eV to 2.1 eV with undoped and doped HA. Theoretically obtained band gap and optical behaviour of the systems are well correlated with the experimental findings. Moreover, the use of marine biowaste from cuttlefish bone, as the source of HA; low cost and promising UV absorption can have a potential application as UV protective sunscreen filters. © 2020 The American Ceramic Society
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    Soy protein isolate films: a biodegradable solution for UV protection alternatives
    (Springer, 2025) Nowl, M.S.; Ambili, V.; Gautam, V.; Dutta, S.; Mandal, S.
    The uncompromising need to protect against harmful UVA and UVB radiation and to alleviate plastic pollution has catalyzed the development of innovative, eco-friendly materials. This study presents a solution by developing a transparent coating derived from Soy Protein Isolate (SPI), offering UV protection as well as sustainable bioplastic alternatives to synthetic polymers. The structural and chemical properties of SPI coatings, highlighting their UV protective capabilities, were analyzed using UV absorption spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR), and High-Resolution Liquid Chromatography-Mass Spectrometry (HR-LCMS). X-ray photoelectron spectroscopy (XPS) analysis showed decrease in carbon composition between SPI powder and film, suggesting a different surface composition for the film from powder, whereas denaturation was further confirmed by DSC. Contact angle measurement gives insights about the surface properties of the film and HR-LCMS gives the amino acids present in SPI. The biodegradability of SPI, coupled with its durability and transparency, underscores its potential as a versatile host material for various coatings. highlighting its additional advantage. From the FE-SEM study, the coating shows uniformity, which presents an innovative approach to transparent coatings. Notably, alongside transparency, the inherent UV absorption properties of SPI remained consistent before and after denaturation, showing potential applications in UV protective biodegradable coatings for various industrial applications, promoting eco-friendly alternatives to synthetic polymers. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.