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- A hydroxyapatite–Fe2O3 based material of natural origin as an active sunscreen filterPublication . Piccirillo, C.; Rocha, C.; Tobaldi, D. M.; Pullar, R. C.; Labrincha, J. A.; Ferreira, M. O.; Castro, Paula M. L.; Pintado, M. E.The use of sunscreens as protective barriers against skin damage and cancer, by absorbing harmful UVA and UVB rays, is becoming an increasingly important issue. Such products are usually based on TiO2 or ZnO, although both Fe2O3 and hydroxyapatite (Ca10(PO4)6(OH)2, HAp) doped with metal ions have been reported as being ultraviolet (UV) absorbing materials. HAp is the main component of bone; it is, therefore, highly biocompatible. In the present work, an iron-doped HAp-based material, containing both Fe ions substituted into the HAp structure and iron oxide in hematite (a-Fe2O3) form, was successfully developed from waste cod fish bones. This was achieved through a simple process of treating the bones in a Fe(II) containing solution, followed by heating at 700 C. The material showed good absorption in the whole UV range and did not form radicals when irradiated. The sunscreen cream formulated with this material could be used as a broad sunscreen protector (lcrit > 370 nm), showing high absorption both in the UVA and UVB ranges. Because of its absorption properties it would be classified as 5 star protection according to the Boots UVA star rating system. The cream is also photostable, and does not cause irritation or erythema formation when in contact with the human skin. These results show that a food by-product such as fish bones could be converted into a valuable product, with potential applications in health care and cosmetics. This is the first time a HAp-based sunscreen cream has been developed and validated as a proof of concept.
- Chitosan in oral health: a proof of conceptPublication . Costa, E. M.; Silva, Sara; Cardelle-Cobas, A.; Madureira, A. R.; Ferreira, M. O.; Tavaria, Freni K.; Pintado, M. M.Nowadays chitosan has established itself as a high sought material due to its biocompatibility, reduced toxicity and highpercentage of amino groups that confer it specific functionalities, including antimicrobial activity and acceleration of woundhealing, and studies into chitosan’s applicability have shown chitosan’s potential and feasibility. One of the possible fieldsof application for chitosan based products is the oral cavity, since several of the existing oral health products possesssecondary effects. The aim of this work was to prove that chitosan is a feasible component for oral health productsbiofabrication. As such a chitosan based mouthwash was developed and validated through assessment ofin vitroandin vivoantimicrobial activity, antibiofilm activity and sensory properties. The results obtained showed that it was possible tosuccessfully incorporate chitosan in an oral care product while retaining a considerable antimicrobial activity.In vitrotestingdemonstrated that the chitosan mouthwash possessed a wide range of antimicrobial activity against oral pathogens andwas capable of inhibiting microbial adherence and biofilm formation. Direct comparison with two commercial mouthwashesshowed that the chitosan mouthwash possessed stronger activity than both reference samples.In vivotesting showedthat the chitosan mouthwash was very effective in reducing enterococci and streptococci bacterial counts up to 30 min.after rinsing. Overall, the present shows a successful development of a chitosan-based product and is a tangible proof ofconcept for future utilization of chitosan in oral health.
- Effect of preparation and processing conditions on UV absorbing properties of hydroxyapatite-Fe2O3 sunscreenPublication . Teixeira, M. A. C.; Piccirillo, C.; Tobaldi, D. M.; Pullar, R. C.; Labrincha, J. A.; Ferreira, M. O.; Castro, Paula M. L.; Pintado, M. M. E.The development of innovative, safe and non-photocatalytic sunscreens is urgently needed, as it is essential to have sunscreen filters offering appropriate UV protection without damaging the environment and/or generating free radicals when in contact with the skin. Hydroxyapatite (Ca-10(PO4)(6)(OH)(2), HAp) when substituted with iron has UV protection properties and is not photocatalytic; HAp was used to make a sunscreen filter by treating cod fish bones in an iron-containing solution, and then calcining them at 700 degrees C. Here we present a systematic and advanced study on this material, to obtain a sunscreen with improved UV absorbing properties, Bones were treated with three different iron salts - Fe(II) chloride, Fe(II) lactate and Fe(III) nitrate - under various pH conditions. Results showed that Fe(II) chloride in basic pH led to the most effective iron inclusion, High energy ball milling or ultrasound were investigated to increase surface area and corresponding UV absorption; high energy ball milling treatment led to the best optical properties. The optimum powders were used to formulate UV protection creams, which showed Sun Protection Factor (SPF) values significantly superior to the control cream (up to 4.1). Moreover the critical wavelength (lambda(crit)) was >370 nm (388-389 nm) and UVA/UVB ratios were very close to 1. With these properties these sunscreens can be classified as broad UV protectors. Results also showed that combining these powders with other sunscreens (i.e. titanium dioxide), a synergic effect between the different components was also observed. This investigation showed that HAp-based sunscreens of marine origin are a valid alternative to commercial products, safe for the health of the customers and, being non-photocatalytic, do not pose a threat to the environment.