Films of chitosan and natural modified hydroxyapatite as effective UV-protecting, biocompatible and antibacterial wound dressings

Abstract

Chitosan is a natural polysaccharide widely used in biomedicine, for instance for wound dressing. Hydroxyapatite is a very bioactive calcium phosphate which, if modified with an appropriate element (iron Fe), can also have UVabsorbing properties. In this work, we report the study of films of chitosan incorporated with iron-modified hydroxyapatite of natural origin (from cod fish bones); this combination led to an innovative chitosan-based material with excellent and advanced functional properties. The films showed very high UV absorption (Ultraviolet Protection Factor (UPF) value higher than 50). This is the first time that a chitosan-based material has shown such high UV protection properties. The films also showed to be non-cytotoxic, and possessed antimicrobial activity towards both Gram-positive and negative strains. Their mechanical properties, optimised with an experimental design approach, confirmed their potential use as multifunctional wound dressing, capable of reducing bacterial infections and, at the same time, protecting from UV light.

Novel Trends into the Development of Natural Hydroxyapatite-Based Polymeric Composites for Bone Tissue Engineering

“…There are numerous similarities between CS and the native glycosaminoglycans’ structure, which improves the rate of bone regeneration. Thus, Cunha et al noted that amino and hydroxyl functional groups enable chemical modifications, increasing the potential of CS-based nanocomposites, which have gained significant attention in this domain [ 39 , 40 ]. Such an application can be seen in Figure 2 , illustrating the inhibition phenomenon of bacterial attachment.…”

The Use of Calcium Phosphates in Cosmetics, State of the Art and Future Perspectives

“…In recent years, HA has been proposed as a safe sunscreen ingredient, and the interest in CaPs for this application is growing [195,196]. In the literature, there are several examples that report the preparation of HA as a safe inorganic sunscreen ingredient to replace ZnO and TiO 2 [197][198][199][200][201][202][203][204][205][206][207][208][209][210][211]. Indeed, it was found that HA shows not only non-toxicity and biocompatibility properties, but also screening capability, high dermal tolerance, and a lower whitening effect than other inorganic sunscreen agents.…”

“…They noticed excellent UV-absorbing properties, antibacterial activity, and non-cytotoxicity. This material could be used for wound dressing, because it reduces bacterial infection while protecting wounds from UV exposure [205]. Another example is the work of Ghazali et al, which reports the preparation of an active sunscreen ingredient from clamshells by substituting calcium ions of HA structure with Fe 3+ or Mn 2+ [210].…”

Natural Ingredients in Functional Coatings—Recent Advances and Future Challenges

“…These coating materials can be in form of hydrogels, films or delivery systems deposited on support materials, their main characteristic being a good compatibility between the components and the active substances [52]. For the development of a proper coating material, various aspects need to be considered: (i) when the coating is obtained only from polymers (natural or synthetic), the advantage is the flexibility of the material, but the drawback is the lack of mechanical strength and chemical stability [53]; (ii) for coatings obtained only from inorganic materials, there is a poor adhesive strength on surfaces, film-forming ability, or the tendency to aggregate [54]; (iii) lack of stability and reduced activity under infection conditions and variable pH of different active substances can be removed by the proper use of the coating material [55]; (iv) the additives used to enhance the beneficial properties must not affect the main properties and the functionality of the primary coating material (i.e., antimicrobial) [56].…”