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

Distance-based integration method for human skin type identification

Although identifying human skin types is essential in dermatology, cosmetology, and facial recognition, the classification of human skin types is challenging due to the complex nature, varied characteristics, and the influence of external factors. Traditional methods for skin type identification often rely on subjective assessments, leading to inconsistent and inaccurate results. Therefore, this paper proposes a novel method named a distance-based integration method to identify skin types based on the Fitzpatrick skin scale, also known as the Fitzpatrick skin type. This study focuses on the objective distance measurement, integrated with the Fuzzy Analytic Hierarchy Process (AHP). The objective distance was utilized to determine the distance between each HEX color code for a clinical image and each target skin type. The Fuzzy AHP algorithm was employed to calculate the total score for each target class to identify human skin type. For this study, 1,022 images of human skin were used in the experiment. The results indicated that the proposed method achieved a high average accuracy of 93 %, precision of 80 %, and specificity of 96 %.

A Comparative Study of Cerium(III) and Cerium(IV) Phosphates for Sunscreens

Crystalline cerium(III) phosphate (CePO4), cerium(IV) phosphates, and nanocrystalline ceria are considered to be promising components of sunscreen cosmetics. This paper reports on a study in which, for the first time, a quantitative comparative analysis was performed of the UV-shielding properties of CePO4, Ce(PO4)(HPO4)0.5(H2O)0.5, and CePO4/CeO2 composites. Both the sun protection factor and protection factor against UV-A radiation of the materials were determined. Ce(PO4)(HPO4)0.5(H2O)0.5 was shown to have a sun protection factor of 2.9, which is comparable with that of nanocrystalline ceria and three times higher than the sun protection factor of CePO4. Composites containing both cerium dioxide and CePO4 demonstrated higher sun protection factors (up to 1.8) than individual CePO4. When compared with the TiO2 Aeroxide P25 reference sample, cerium(III) and cerium(IV) phosphates demonstrated negligible photocatalytic activity. A cytotoxicity analysis performed using two mammalian cell lines, hMSc and NCTC L929, showed that CePO4, Ce(PO4)(HPO4)0.5(H2O)0.5, and nanocrystalline ceria were all non-toxic. The results of this comparative study indicate that cerium(IV) phosphate Ce(PO4)(HPO4)0.5(H2O)0.5 is more advantageous for use in sunscreens than either cerium(III) phosphate or CePO4/CeO2 composites, due to its improved UV-shielding properties and low photocatalytic activity.

Natural, biphasic calcium phosphate from fish bones for enamel remineralization and dentin tubules occlusion

OBJECTIVES

A calcium phosphate extracted from fish bones (CaP-N) was evaluated for enamel remineralization and dentinal tubules occlusion.

METHODS

CaP-N was characterized by assessing morphology by SEM, crystallinity by PXRD, and composition by ICP-OES. CaP-N morphology, crystallinity, ion release, and pH changes over time in neutral and acidic solutions were studied. CaP-N was then tested to assess remineralization and dentinal tubules occlusion on demineralized human enamel and dentin specimens (n = 6). Synthetic calcium phosphate in form of stoichiometric hydroxyapatite nanoparticles (CaP-S) and tap water were positive and negative controls, respectively. After treatment (brush every 12 h for 5d and storage in Dulbecco's modified PBS), specimens' morphology and surface composition were assessed (by SEM-EDS), while the viscoelastic behavior was evaluated with microindentation and DMA.

RESULTS

CaP-N consisted of rounded microparticles (200 nm - 1 µm) composed of 33 wt% hydroxyapatite and 67 wt% β-tricalcium phosphate. In acidic solution, CaP-N released calcium and phosphate ions thanks to the preferential β-tricalcium phosphate phase dissolution. Enamel remineralization was induced by CaP-N comparably to CaP-S, while CaP-N exhibited a superior dentinal tubule occlusion than CaP-S, forming mineral plugs and depositing new nanoparticles onto demineralized collagen. This behavior was attributed to its bigger particle size and increased solubility. DMA depth profiling and SEM showed an excellent interaction between the newly formed mineralized structures and the pristine tissue, particularly at the exposed collagen fibrils.

SIGNIFICANCE

CaP-N demonstrated very good remineralizing and occlusive activity in vitro, comparable to CaP-S, thus could be a promising circular economy alternative therapeutic agent for dentistry.

Nanotechnology in toothpaste: Fundamentals, trends, and safety

Several studies have revealed that healthcare nanomaterials are widely used in numerous areas of dentistry, including prevention, diagnosis, treatment, and repair. Nanomaterials in dental cosmetics are utilized to enhance the efficacy of toothpaste and other mouthwashes. Nanoparticles are added to toothpastes for a variety of reasons, including dental decay prevention, remineralization, hypersensitivity reduction, brightening, and antibacterial qualities. In this review, the benefits and uses of many common nanomaterials found in toothpaste are outlined. Additionally, the capacity and clinical applications of nanoparticles as anti-bacterial, whitening, hypersensitivity, and remineralizing agents in the treatment of dental problems and periodontitis are discussed.

Multifunctional Nanomaterials for Biofortification and Protection of Tomato Plants

Calcium phosphate nanoparticles were doped with zinc ions to produce multifunctional nanomaterials for efficient agronomic fortification and protection of plants. The resulting round-shaped nanoparticles (nanoZn) were composed of 20.3 wt % Ca, 14.8 wt % P, and 13.4 wt % Zn and showed a pH-controlled solubility. NanoZn were stable in aqueous solutions at neutral pH but dissolved in citric acid at pH 4.5 (i.e., the pH inside tomato fruits), producing a pH-responsive delivery of the essential nutrients Ca, P, and Zn. In fact, the foliar application of nanoZn on tomato plants provided tomatoes with the highest Zn, Ca, and P contents (causing, respectively, a 65, 65, and 15% increase with respect to a conventional treatment with ZnSO4) and the highest yields. Additionally, nanoZn (100 ppm of Zn) inhibited in vitro the growth of Pseudomonas syringae (Ps), the main cause of bacterial speck, and significantly reduced Ps incidence and mortality in tomato seeds, previously inoculated with the pathogen. Therefore, nanoZn present dual agricultural applicability, enriching crops with nutrients with important metabolic functions in humans and simultaneously protecting the plants against important bacterial-based diseases, with considerable negative impact in crop production.

The Comparative Dermal Stimulation Potential of Constant-Volume and Constant-Amount Diluted Calcium Hydroxylapatite Injections Versus the Concentrated Form

INTRODUCTION

Biostimulation properties of diluted and hyperdiluted calcium hydroxylapatite (CaHA) injections have become increasingly popular. However, the existing data are insufficient to certify a particular dose-response pattern.

OBJECTIVE

To assess and compare the dermal stimulation potentials of different concentrations of CaHA injections.

MATERIALS AND METHODS

Two independent experiments (Experiment-1: constant injection volume vs Experiment-2: constant CaHA amount) included 4 study groups each, and these experimental groups were placed consecutively on the abdominal skin of a juvenile Yorkshire pig. Histopathological and immunohistochemical stainings were performed on punch biopsy materials collected 4 months after the injection day.

RESULTS

The fibroblast count significantly decreased upon dilution from 1:3 to 1:19 in experiment 1 ( p = .000) but still higher than the control group. In experiment 1, the collagen density of the concentrated form was more elevated than the 1:19 dilution and the negative control groups ( p = .034 and .000, respectively) but similar to the 1:3 dilution ( p = .123). No significant difference was observed between the groups regarding collagen density with a standard amount of CaHA (0.2 mL, 30%) ( p > .05).

CONCLUSION

Despite the efficacy being more pronounced till 1:3 dilution, hyperdiluted CaHA at any dilution ratio up to 1:19 can provide a higher fibroblast count than the negative control group.

Phosphorus recovery from wastewater via calcium phosphate precipitation: A critical review of methods, progress, and insights

Phosphorus (P) is one of the important elements for human, animal, and plant life. Due to the development of the circular economy in recent years, the recovery of P from wastewater has received more attention. Recovery of P from domestic, industrial, and agricultural wastewater in the form of calcium phosphate (CaP) by precipitation/crystallization process presents a low-cost and effective method. Recovered CaP could be used as P fertilizer and for other industrial applications. This review summarizes the effects of supersaturation, pH, seed materials, calcium (Ca) source, and wastewater composition, on the precipitation/crystallization process. The recovery efficiency and value proposition of recovered CaP were assessed. This in-depth analysis of the literature reports identified the process parameters that are worth further optimization. The review also provides perspectives on future research needs on expanding the application field of recovered CaP and finding other more economical and environmentally friendly Ca sources.

Biomineralization: A new tool for developing eco-sustainable Ti-doped hydroxyapatite-based hybrid UV filters

It is well known that the prolonged exposure to UV radiation from sunlight can compromise human health and is particularly damaging to the skin, leading to sunburn, photo-aging and skin cancer. Sunscreen formulations containing UV-filters present a barrier against solar UV and help to mitigate the harmful effects however, concern about their safety for both human and environmental health is still a much-debated topic. EC regulations classify UV-filters depending on their chemical nature, particle size, and mechanism of action. Furthermore, it regulates their use in cosmetic products with specific limitations in terms of concentration (organic UV filters) and particle size and surface modification to reduce their photo-activity (mineral UV filters). The regulations have prompted researchers to identify new materials that show promise for use in sunscreens. In this work, biomimetic hybrid materials composed of titanium-doped hydroxyapatite (TiHA) grown on two different organic templates, derived from animal (gelatin - from pig skin) and vegetable (alginate - from algae) sources. These novel materials were developed and characterized to obtain sustainable UV-filters as a safer alternative for both human and ecosystem health. This 'biomineralization' process yielded TiHA nanoparticles that demonstrated high UV reflectance, low photoactivity, good biocompatibility and an aggregate morphology which prevents dermal penetration. The materials are safe for topical application and for the marine environment; moreover, they can protect organic sunscreen components from photodegradation and yield long-lasting protection.

Calcium phosphates from fish bones in sunscreen: An LCA and toxicity study of an emerging material for circular economy

The use of sustainable and natural materials is an ever-increasing trend in cosmetic. Natural calcium phosphate (CaP-N) from food by-products and especially from fisheries (i.e., bones), has been suggested as a sustainable option to chemicals commonly used in cosmetic products, in particular to UV-filters in sunscreens. However, the environmental benefits and impacts of its production and use are still uncertain as they have never been quantified. In this paper, we report on toxicological characterization of CaP-N produced from incineration of fish meal in a pilot scale plant. Furthermore, we quantified the environmental burdens linked to the partial substitution of UV-filters by CaP-N through the life cycle assessment (LCA) comparing CaP-N with zinc oxide nanoparticles (ZnO NPs) as alternative option. CaP-N consists in a biphasic mixture 53:47 of hydroxyapatite:β-tricalcium phosphate, and is made of round particles with a diameter in the range of a few microns. Toxicity tests on 4 aquatic species (Dunaliella tertiolecta, Tigriopus fulvus, Corophium insidiosum and Gammarus aequicauda) revealed that CaP-N does not produce any adverse effect, all the species showing EC/LC50 values higher than 100 mg L^-1. Moreover, during the 96 h acute toxicity test on C. insidiosum, which is a tube-building species, the specimens built their tubes with the available CaP-N, further attesting the non-toxicity of the material. The LCA study showed that the environmental performance of CaP-N is better than that of ZnO NPs for 11 out of 16 impact categories analysed in this study, especially for the categories Ecotoxicity and Eutrophication of freshwaters (an order of magnitude lower), and with the exception of fossil resources for which CaP-N has a significantly higher impact than ZnO NPs (+140 %). Concluding, our study demonstrates that the replacement of ZnO NPs with CaP-N thermally extracted from fish bones in cosmetic products can increase their safety and sustainability.

Effect of L-Glutamic Acid on the Composition and Morphology of Nanostructured Calcium Phosphate as Biomaterial

Calcium phosphate (CaP) with several chemical compositions and morphologies was prepared by precipitation using aqueous solutions of L-Glutamic acid (H₂G) and calcium hydroxide, both mixed together with an aqueous solution (0.15 M) of phosphoric acid. Plate-shaped dicalcium phosphate dihydrate (brushite) particles were obtained and identified at a lower concentration of the solution of the reactants. The Ca/P ratio deduced by EDS was ~1, as expected. The nanoscale dimension of carbonate apatite and amorphous calcium phosphate, with variable Ca/P ratios, were revealed by X-ray diffraction (XRD) and scanning electron microscopy and energy dispersive X-ray spectroscopy analysis (SEM-EDS). They were characterized in medium and high concentrations of calcium hydroxide (0.15 M and 0.20 M). The equilibria involved in all the reactions in aqueous solution were determined. The thermodynamic calculations showed a decrease in the amount of chelate complexes with an increase in pH, being the opposite of [CaPO₄^-] and [CaHG⁺]. This fluctuation showed an evident influence on the morphology and polymorphism of CaP particles obtained under the present experimental conditions, with potential use as a biomaterial.

Potential Cosmetic Active Ingredients Derived from Marine By-Products

The market demand for marine-based cosmetics has shown a tremendous growth rate in the last decade. Marine resources represent a promising source of novel bioactive compounds for new cosmetic ingredient development. However, concern about sustainability also becomes an issue that should be considered in developing cosmetic ingredients. The fisheries industry (e.g., fishing, farming, and processing) generates large amounts of leftovers containing valuable substances, which are potent sources of cosmeceutical ingredients. Several bioactive substances could be extracted from the marine by-product that can be utilized as a potent ingredient to develop cosmetics products. Those bioactive substances (e.g., collagen from fish waste and chitin from crustacean waste) could be utilized as anti-photoaging, anti-wrinkle, skin barrier, and hair care products. From this perspective, this review aims to approach the potential active ingredients derived from marine by-products for cosmetics and discuss the possible activity of those active ingredients in promoting human beauty. In addition, this review also covers the prospect and challenge of using marine by-products toward the emerging concept of sustainable blue cosmetics.

Calcium Orthophosphate (CaPO4)-Based Bioceramics: Preparation, Properties, and Applications

Various types of materials have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A short time later, such synthetic biomaterials were called bioceramics. Bioceramics can be prepared from diverse inorganic substances, but this review is limited to calcium orthophosphate (CaPO4)-based formulations only, due to its chemical similarity to mammalian bones and teeth. During the past 50 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the CaPO4-based implants would remain biologically stable once incorporated into the skeletal structure or whether they would be resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed, and such formulations became an integrated part of the tissue engineering approach. Now, CaPO4-based scaffolds are designed to induce bone formation and vascularization. These scaffolds are usually porous and harbor various biomolecules and/or cells. Therefore, current biomedical applications of CaPO4-based bioceramics include artificial bone grafts, bone augmentations, maxillofacial reconstruction, spinal fusion, and periodontal disease repairs, as well as bone fillers after tumor surgery. Prospective future applications comprise drug delivery and tissue engineering purposes because CaPO4 appear to be promising carriers of growth factors, bioactive peptides, and various types of cells.

Atomic Details of Biomineralization Proteins Inspiring Protein Design and Reengineering for Functional Biominerals

Biominerals are extraordinary materials that provide organisms with a variety of functions to support life. The synthesis of biominerals and organization at the macroscopic level is a consequence of the interactions of these materials with proteins. The association of biominerals and proteins is very ancient and has sparked a wealth of research across biological, medical and material sciences. Calcium carbonate, hydroxyapatite, and silica represent widespread natural biominerals. The atomic details of the interface between macromolecules and these biominerals is very intriguing from a chemical perspective, considering the association of chemical entities that are structurally different. With this review I provide an overview of the available structural studies of biomineralization proteins, explored from the Protein Data Bank (wwPDB) archive and scientific literature, and of how these studies are inspiring the design and engineering of proteins able to synthesize novel biominerals. The progression of this review from classical template proteins to silica polymerization seeks to benefit researchers involved in various interdisciplinary aspects of a biomineralization project, who need background information and a quick update on advances in the field. Lessons learned from structural studies are exemplary and will guide new projects for the imaging of new hybrid biomineral/protein superstructures at the atomic level.

Criticisms in the Development of High-Protection and Broad-Spectrum “Natural/Organic” Certifiable Sunscreen

Attention to environmental issues has become increasingly important in recent years and also massively affects the cosmetics sector. In this context, sunscreens are questioned due to the proven or believed ecotoxicity of organic ultraviolet (UV) filters. This has pushed developers increasingly towards the use of inorganic filters, which can prove difficult to spread with low compliance. We faced the problem by proposing a rational approach based on the evaluation of the morphology of the inorganic material, as the real dimension does not often correspond to the characteristics declared by the producers because the material itself tends to aggregate. A combination of a specially selected inorganic filter is required to formulate Cosmetic Products with a Natural and Sustainable Connotation (CPCNS) standards.

Dental tissue remineralization by bioactive calcium phosphate nanoparticles formulations

Recent health care products are based on formulations claimed to provide enamel remineralization and dentinal tubules occlusion through calcium-phosphate bioactive nanocompounds (ion-doped hydroxyapatite and precursor, amorphous calcium phosphate nanoparticles). This study aimed to characterize, test, and compare for the first time the structure and performance of a representative, market-available sample of remineralizing toothpastes and topical mousses. Formulations were characterized to determine their composition and investigate the presence of bioactive compounds and doping elements. A conventional fluoride-containing toothpaste was used as reference. The enamel remineralization and efficacy of dentinal tubules occlusion by tested formulations were investigated ex vivo on human hard tissues. All formulations containing Ca-P bioactive nanocompounds showed remineralizing ability by epitaxial growth of a layer showing the morphology and composition of human hydroxyapatite. Such layers also embedded nanosilica clusters. The presence of doping elements or casein phosphopeptide seemed essential to allow such performances, especially when hydroxyapatite and amorphous calcium phosphate compounds were doped with small amounts of CO₃²⁻, F⁻, Mg²⁺, and Sr²⁺. Topical mousse formulations showed a higher tubules occlusion capability than toothpastes, independently from their composition. Therefore, all tested formulations could be useful in restoring tooth structures in a biomimetic way, contrasting dental demineralization processes leading to caries.

Calcium phosphate and silicate-based nanoparticles: history and emerging trends

Bulk calcium phosphates and silicate-based bioglasses have been extensively studied since the early 1970s due to their unique capacity to bind to host bone, which led to their clinical translation and commercialization in the 1980s. Since the mid-1990s, researchers have synthesized nanoscale calcium phosphate and silicate-based particles of increased specific surface area, chemical reactivity and solubility which offer specific advantages as compared to their bulk counterparts. This review provides a critical perspective on the history and emerging trends of these two classes of ceramic nanoparticles. Their synthesis and functional properties in terms of particle composition, size, shape, charge, dispersion, and toxicity are discussed as a function of relevant processing parameters. Specifically, emerging trends such as the influence of ion doping and mesoporosity on the biological and pharmaceutical performance of these nanoparticles are reviewed in more detail. Finally, a broad comparative overview is provided on the physicochemical properties and applicability of calcium phosphate and silicate-based nanoparticles within the fields of i) local delivery of therapeutic agents, ii) functionalization of biomaterial scaffolds or implant coatings, and iii) bio-imaging applications.