Inorganic UV filters

Advancements in sunscreen formulations: integrating polyphenolic nanocarriers and nanotechnology for enhanced UV protection

Sunscreens are essential in protecting the skin from harmful effects of ultraviolet radiation (UVR). These formulations, designed to absorb, block, or scatter UVR, offer vital protection against skin aging, sunburns, and the development of skin cancers like melanomas. However, some sunscreens, especially those containing organic/chemical compounds, can cause allergic reactions. To address this, researchers are extensively investigating formulations that incorporate plant extracts rich in polyphenols, such as flavonoids and carotenoids, which can be considered safer alternatives. Products derived from plants are commonly used in cosmetics to counteract skin aging due to their antioxidant activity that combat harmful free radicals. This review focuses on evaluating the advancements in chemical and natural sunscreens, exploring the integration of polyphenolic nanocarriers within sunscreen formulas, their interaction with UVR, and utilizing nanotechnology to enhance their effectiveness. An attempt has been made to highlight the concerns related to toxicity associated with their use and notable advancements in the regulatory aspects governing their utilization.

Behavioral and biochemical responses of the marine polychaete Perinereis aibuhitensis to 2-ethylhexyl-4-methoxycinnamate (EHMC) exposure

2-ethylhexyl-4-methoxycinnamate (EHMC) is a commonly used UV filter, and is receiving increasing concerns due to its ubiquitous occurrence in a variety of environmental media and potential adverse effects. This study was aimed to assess the ecotoxicological potentials of EHMC on the marine polychaete Perinereis aibuhitensis. To this end, ragworms were exposed to 2, 20, 200 μg/L EHMC for 14 days and multiple toxicological endpoints were investigated. The results showed that EHMC significantly reduced burrowing rate, but did not affect AChE activity. Exposure to EHMC significantly elevated the activities of SOD and CAT and decreased the levels of lipid peroxidation. Besides, the induction of AKP activity indicated a stimulated immune response in the ragworms when exposed to high concentration of EHMC. Furthermore, the upregulated expression of caspase-8 suggested that EHMC might induce apoptosis in ragworms via the death receptor-mediated extrinsic pathway. Our findings highlight the potential environmental risks of EHMC to marine ecosystems.

A Spike-like Self-Assembly of Polyaspartamide Integrated with Functionalized Nanoparticles

The integration of nanoparticles (NPs) into molecular self-assemblies has been extensively studied with the aim of building well-defined, ordered structures which exhibit advanced properties and performances. This study demonstrates a novel strategy for the preparation of a spike-like self-assembly designed to enhance UV blocking. Poly(2-hydroxyethyl aspartamide) (PHEA) substituted with octadecyl chains and menthyl anthranilate (C18-M-PHEA) was successfully synthesized by varying the number of grafted groups to control their morphology and UV absorption. The in situ incorporation of polymerized rod-like TiO2 within the C18-M-PHEA self-aggregates generated spike-like self-assemblies (TiO2@C18-M-PHEA) with a chestnut burr structure in aqueous solution. The results showed that the spike-like self-assemblies integrated with TiO2 NPs exhibited a nine-fold increase in UV protection by simultaneous UV absorption and scattering compared with the pure TiO2 NPs formed via a bulk mixing process. This work provides a novel method for UV protection using self-assembling poly(amino acid)s derivatives integrated with functional nanoparticles to tune their morphology and organization.

Complex coacervate-derived hydrogel with asymmetric and reversible wet bioadhesion for preventing UV light-induced morbidities

Protecting the skin from UV light irradiation in wet and underwater environments is challenging due to the weak adhesion of existing sunscreen materials but highly desired. Herein we report a polyethyleneimine/thioctic acid/titanium dioxide (PEI/TA/TiO2) coacervate-derived hydrogel with robust, asymmetric, and reversible wet bioadhesion and effective UV-light-shielding ability. The PEI/TA/TiO2 complex coacervate can be easily obtained by mixing a PEI solution and TA/TiO2 powder. The fluid PEI/TA/TiO2 coacervate deposited on wet skin can spread into surface irregularities and subsequently transform into a hydrogel with increased cohesion, thereby establishing interdigitated contact and adhesion between the bottom surface and skin. Meanwhile, the functional groups between the skin and hydrogel can form physical interactions to further enhance bioadhesion, whereas the limited movement of amine and carboxyl groups on the top hydrogel surface leads to low adhesion. Therefore, the coacervate-derived hydrogel exhibits asymmetric adhesiveness on the bottom and top surfaces. Moreover, the PEI/TA/TiO2 hydrogel formed on the skin could be easily removed using a NaHCO3 aqueous solution without inflicting damage. More importantly, the PEI/TA/TiO2 hydrogel can function as an effective sunscreen to block UV light and prevent UV-induced MMP-9 overexpression, inflammation, and DNA damage in animal skin. The advantages of PEI/TA/TiO2 coacervate-derived hydrogels include robust, asymmetric, and reversible wet bioadhesion, effective UV light-shielding ability, excellent biocompatibility, and easy preparation and usage, making them a promising bioadhesive to protect the skin from UV light-associated damage in wet and underwater environments.

Nanogel Containing Gamma-Oryzanol-Loaded Nanostructured Lipid Carriers and TiO2/MBBT: A Synergistic Nanotechnological Approach of Potent Natural Antioxidants and Nanosized UV Filters for Skin Protection

The human skin is a recurring target of external aggressions, such as UV radiation, leading to exacerbation of the aging process and the occurrence of skin diseases, such as cancer. Hence, preventive measures should be taken to protect it against these aggressions, consequently decreasing the chance of disease development. In the present study, a topical xanthan gum nanogel containing gamma-oryzanol-loaded nanostructured lipid carriers (NLCs) and nanosized UV filters TiO₂ and methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) was developed to assess their synergistic potential in having multifunctional skin beneficial properties. The developed NLCs contained the natural-based solid lipids shea butter and beeswax, liquid lipid carrot seed oil, and the potent antioxidant gamma-oryzanol, with an optimum particle size for topical application (<150 nm), good homogeneity (PDI = 0.216), high zeta potential (-34.9 mV), suitable pH value (6), good physical stability, high encapsulation efficiency (90%), and controlled release. The final formulation, a nanogel containing the developed NLCs and the nano UV filters, showed high long-term storage stability and high photoprotection ability (SPF = 34) and resulted in no skin irritation or sensitization (rat model). Hence, the developed formulation showed good skin protection and compatibility, demonstrating promise as a new platform for the future generation of natural-based cosmeceuticals.

A Novel Approach in Skin Care: By-Product Extracts as Natural UV Filters and an Alternative to Synthetic Ones

The cosmetic industry has been focusing on replacing synthetic ingredients with natural ones, taking advantage of their bioactive compounds. This work assessed the biological properties of onion peel (OP) and passion fruit peel (PFP) extracts in topical formulations as an alternative to synthetic antioxidants and UV filters. The extracts were characterized regarding their antioxidant capacity, antibacterial capacity and sun protection factor (SPF) value. Results revealed that the OP extract exhibited better results, which can result from the high concentrations of quercetin, as identified and quantified in HPLC analysis. Afterward, nine formulations of O/W creams were produced with minor changes in the quantity of additives: OP and PFP extract (natural antioxidants and UV filters), BHT (synthetic antioxidant) and oxybenzone (synthetic UV filter). The stability of the formulations was determined for 28 days; it was verified that they remained stable throughout the study period. The assays of the formulations' antioxidant capacity and SPF value revealed that OP and PFP extracts have some photoprotective properties and are excellent sources of antioxidants. As a result, they can be incorporated in daily moisturizers with SPF and sunscreens replacing and/or diminishing the quantities of synthetic ingredients, reducing their negative effects on human health and the environment.

Environmental impacts due to the use of sunscreen products: a mini-review

Sunscreen use has increased in recent years, as sunscreen products minimize the damaging effects of solar radiation. Active ingredients called ultraviolet (UV) filters or UV agents, either organic or inorganic, responsible for defending skin tissue against harmful UV rays, are incorporated in sunscreen formulations. UV agents have a serious impact on many members of bio communities, and they are transferred to the environment either directly or indirectly. Many organic UV filters are found to be accumulated in marine environments because of high values of the octanol/water partition coefficient. However, due to the fact that UV agents are not stable in water, unwanted by-products may be formed. Experimental studies or field observations have shown that organic UV filters tend to bioaccumulate in various aquatic animals, such as corals, algae, arthropods, mollusks, echinoderms, marine vertebrates. This review was conducted in order to understand the effects of UV agents on both the environment and marine biota. In vivo and in vitro studies of UV filters show a wide range of adverse effects on the environment and exposed organisms. Coral bleaching receives considerable attention, but the scientific data identify potential toxicities of endocrine, neurologic, neoplastic and developmental pathways. However, more controlled environmental studies and long-term human use data are limited. Several jurisdictions have prohibited specific UV filters, but this does not adequately address the dichotomy of the benefits of photoprotection vs lack of eco-friendly, safe, and approved alternatives.

The Promise of Emergent Nanobiotechnologies for In Vivo Applications and Implications for Safety and Security

Nanotechnology, the multidisciplinary field based on the exploitation of the unique physicochemical properties of nanoparticles (NPs) and nanoscale materials, has opened a new realm of possibilities for biological research and biomedical applications. The development and deployment of mRNA-NP vaccines for COVID-19, for example, may revolutionize vaccines and therapeutics. However, regulatory and ethical frameworks that protect the health and safety of the global community and environment are lagging, particularly for nanotechnology geared toward biological applications (ie, bionanotechnology). In this article, while not comprehensive, we attempt to illustrate the breadth and promise of bionanotechnology developments, and how they may present future safety and security challenges. Specifically, we address current advancements to streamline the development of engineered NPs for in vivo applications and provide discussion on nano-bio interactions, NP in vivo delivery, nanoenhancement of human performance, nanomedicine, and the impacts of NPs on human health and the environment.

Michler's Ketone: β-Cyclodextrin Host-Guest Inclusion Complex for Enhancing the Ultraviolet Protection Factor of Poplin Cotton Fabric

Michler's ketone (4,4' bis(N,N-dimethylamino)benzophenone) mk is a potential ultraviolet radiation (UVR) absorber in various materials. In this report, we have tested the UVR filtering ability of mk on cotton fabric. The beta-cyclodextrin (β-CD) inclusion complex of mk enhances ultraviolet protection factor (UPF) drastically. The impact of β-CD on the UVR filtering of mk are demonstrated by investigating the guest (mk:absorbers)-host (β-CD:enhancer) inclusion complex. Spectral and molecular docking analysis of mk:β-CD complex infers the vertical insertion of the guest molecule by positioning -C=O group of mk at the center of the host molecule with the exclusion of the terminal atoms of guest molecule outside the β-CD cavity. Thus, the host; β-CD renders an inflexible fit to the guest:mk. The inflexible fit of mk into the β-CD cavity enhances the UVR dissipation when it is incorporated on the poplin cotton fabric. With UPF =46 mk:β-CD complex is proposed as a potential UVR absorber suitable for manufacturing sun protective textiles. The holding of mk by β-CD enhances the UVR dissipation and hence facilitates the native red-shifted emission and non-radiative relaxation by the formation of twisted intramolecular charge transfer in mk.

Herbal products as skincare therapeutic agents against ultraviolet radiation-induced skin disorders

This paper aims to highlight the pharmacological aspects of listed herbal skincare products used for the treatment of various disorders caused due to ultraviolet radiation. The pharmacological aspects include safety and efficacy validation as per regulatory guidelines following internationally accepted scientific principles for their development of skincare products. Herbal products have always been used traditionally for the treatment of various skin ailments and have become more prevalent because of their safety and high efficacy benefits. The incorporation of synthetic molecules and chemical substances in the different medicinal and pharmaceutical formulations is the leading cause of the dermal toxicity. Therefore, the developments of herbal skincare products containing scientifically validated herbal ingredients have better acceptance, respect, and belief in the society. The listed herbal products in this review can help take forward the commercial development of skincare products for therapeutic as well as beauty care purposes from such plants.

Ecotoxicological screening of UV-filters using a battery of marine bioassays

The present study aimed to assess the toxicity of seven UV-filters: zinc oxide nanoparticles (nZnO, particle size <100 nm), titanium dioxide nanoparticles (nTiO₂, primary particle size 21 nm), 2-ethylhexyl-4-methoxycinnamate (EHMC), 4-methylbenzylidene camphor (4-MBC), avobenzone (AVO), octocrylene (OCTO) and benzophenone-3 (BP-3) on three species: Aliivibrio fischeri (inhibition of bioluminescence), Phaeodactylum tricornutum (growth inhibition) and Ficopomatus enigmaticus (larval development success). Results showed nTiO₂ to be the most toxic for P. tricornutum (EC₅₀ 0.043 mg L^-1), while no effect was observed in A. fischeri and F. enigmaticus. EHMC was the most toxic to A. fischeri (EC₅₀ 0.868 mg L^-1 (15 min) and 1.06 mg L^-1 (30 min)) and the second most toxic to P. tricornutum. For F. enigmaticus, the lowest percentages of correct development resulted from 4-MBC exposure, with EC₅₀ of 0.836 mg L^-1. Overall, AVO induced low toxicity to every assessed species and OCTO was the least toxic for F. enigmaticus larvae. Considering the results obtained for F. enigmaticus, further larval development assays were performed with nZnO and EHMC under different light (light vs darkness) and temperature (20 and 25 °C) conditions, showing higher percentages of correct development at 25 °C, independently on light/darkness conditions. Under different temperature and photoperiod conditions, nZnO was more toxic than EHMC. Overall, nZnO and EHMC were among the most toxic UV filters tested and, when testing the effects of these UV-filters with temperature the results highlight that the impacts are liable to be lessened at higher temperatures (25 °C compared with 20 °C), in the case of this estuarine polychaete species. Nevertheless, further experiments are necessary to describe the effects of these two UV-filters at different organization levels, to study the toxicity of eventual degradation by-products and to provide more information on the combination of different stressors.

Hydroponic Cultured Ginseng Leaves Zinc Oxides Nanocomposite Stabilized with CMC Polymer for Degradation of Hazardous Dyes in Wastewater Treatment

This study demonstrated the synthesis of o-carboxymethyl chitosan (CMC)-stabilized zinc oxide nanocomposites (ZnO NCs) combined with aqueous leaves extracts of hydroponically cultured ginseng and used as a photocatalyst for the degradation of hazardous dyes, including malachite green (MG), rhodamine B (RB), and congo red (CR) under ultraviolet illumination. Hydroponic ginseng leaves contain bioactive components, namely ginsenoside and natural polyphenol, which prompt ginseng's biological effect. Besides, the CMC polymer is naturally biodegradable, stabilizes the nanoformation and enhances the solubility of ginsenoside. The hydroponic ginseng leaves zinc oxide CMC nanocomposites (GL-CMC-ZnO NCs) were synthesized using the co-precipitation method and characterized using different analytical methods. The FTIR analysis identified significant phytochemicals in the leaves extracts and cotton-shape morphology observed using FE-TEM analysis. The XRD analysis also determined that the crystallite size was 28 nm. The photocatalyst degraded CR, RB, and MG dyes by approximately 87%, 94%, and 96% within contact times of 10, 20, 25, and 30 min, respectively, when the dye concentration was 15 mg/L. As far as our knowledge, this is the first report on hydroponic ginseng NCs incorporated with the CMC polymer for the degradation of hazardous dyes on wastewater treatment. This study can add significant value to large-scale wastewater treatment.

Single cell encapsulation in a Pickering emulsion stabilized by TiO2 nanoparticles provides protection against UV radiation for a biopesticide

A new formulation for biological pest control with significant UV protection capability has been developed in this research. The formulation is based on individual encapsulation of fungal conidia in an oil/water Pickering emulsion. The droplets size of the emulsions was tuned to meet the demands of single conidia encapsulation in the oil droplets. The emulsions are stabilized by amine-functionalized TiO₂ (titania) nanoparticles (NPs). The droplet size, stability, and structure of the emulsions were investigated at different TiO₂ contents and oil/water phase ratios. Most of the emulsions remained stable for 6 months. The structural properties of the Pickering emulsions were characterized by confocal microscopy and high-resolution cryogenic scanning electron microscopy (cryo-HRSEM). The presence of the TiO₂ particles at the interface was confirmed by both confocal microscopy and cryo-HRSEM. Metarhizium brunneum-7 (Mb7) conidia were added to the emulsions. The successful encapsulation of individual conidia in the oil droplets was confirmed by confocal microscopy. The individual encapsulation of the conidia in the emulsions was significantly improved by dispersing the conidia in a 0.02 % Triton X-100 solution prior to emulsification. In addition, the bioassay results have shown, that exposure of the encapsulated conidia to natural UV light did not change their germination rates, however, the unprotected conidia demonstrated a dramatic decrease in their germination rates. These results confirm the UV protection capability of the studied emulsions.

Sunscreens Containing Cyclodextrin Inclusion Complexes for Enhanced Efficiency: A Strategy for Skin Cancer Prevention

Unprotected exposure of skin to solar ultraviolet radiation (UVR) may damage the DNA of skin cells and can lead to skin cancer. Sunscreens are topical formulations used to protect skin against UVR. The active ingredients of sunscreens are UV filters that absorb, scatter, and/or reflect UVR. Preventing the formation of free radicals and repairing DNA damages, natural antioxidants are also added to sunscreens as a second fold of protection against UVR. Antioxidants can help stabilise these formulations during the manufacturing process and upon application on skin. However, UV filters and antioxidants are both susceptible to degradation upon exposure to sunlight and oxygen. Additionally, due to their poor water solubility, natural antioxidants are challenging to formulate and exhibit limited penetration and bioavailability in the site of action (i.e., deeper skin layers). Cyclodextrins (CDs) are cyclic oligosaccharides that are capable of forming inclusion complexes with poorly soluble drugs, such as antioxidants. In this review, we discuss the use of CDs inclusion complexes to enhance the aqueous solubility of antioxidants and chemical UV filters and provide a protective shield against degradative factors. The role of CDs in providing a controlled drug release profile from sunscreens is also discussed. Finally, incorporating CDs inclusion complexes into sunscreens has the potential to increase their efficiency and hence improve their skin cancer prevention.

Visible light. Part II: Photoprotection against visible and ultraviolet light

Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic radiation that reaches the Earth's surface and, as discussed in Part I of this CME, has cutaneous biologic effects, such as pigment darkening and erythema. Photoprotection against VL includes avoiding the sun, seeking shade, and using photoprotective clothing. The organic and inorganic ultraviolet filters used in sunscreens do not protect against VL, only tinted sunscreens do. In the United States, these filters are regulated by the Food and Drug Administration as an over-the-counter drug and are subject to more stringent regulations than in Europe, Asia, and Australia. There are no established guidelines regarding VL photoprotection. Alternative measures to confer VL photoprotection are being explored. These novel methods include topical, oral, and subcutaneous agents. Further development should focus on better protection in the ultraviolet A1 (340-400 nm) and VL ranges while enhancing the cosmesis of the final products.

Sunscreens and their usefulness: have we made any progress in the last two decades?

Sunscreens have now been around for decades to mitigate the Sun's damaging ultraviolet (UV) radiation which, although essential for the existence of life, is a recognized prime carcinogen. Accordingly, have suncreams achieved their intended purposes towards protection against sunburns, skin photo-ageing and the like? Most importantly, however, have they provided the expected protection against skin cancers that current sunscreen products claim to do? In the last two decades, there have been tens, if not hundreds of studies on sunscreens with respect to skin protection against UVB (280‒320 nm)-traditionally sunscreens with rather low sun protection factors (SPF) were intended to protect against this type of radiation-and UVA (320‒400 nm) radiation; a distinction between SPF and UVA protection factor (UVA-PF) is made. Many of the studies of the last two decades have focused on protection against the more skin-penetrating UVA radiation. This non-exhaustive article reviews some of the important facets of what is currently known about sunscreens with regard (i) to the physical UV filters titanium dioxide (TiO₂) and zinc oxide (ZnO) and the mostly photo-unstable chemical UVB/UVA filters (e.g., octinoxate (OMC) and avobenzone (AVO), among others), (ii) to novel chemical sunscreen agents, (iii) to means that minimize the breakdown of chemical filters and improve their stability when exposed to UV sunlight, (iv) to SPF factors, and (v) to a short discussion on non-melanoma skin cancers and melanoma. Importantly, throughout the article we allude to the safety aspects of sunscreens and at the end ask the question: do active ingredients in sunscreen products pose a risk to human health, and what else can be done to enhance protection? Significant loss of skin protection from two well-known commercial suncreams when exposed to simulated UV sunlight. Cream I: titanium dioxide, ethylhexyl triazone, avobenzone, and octinoxate; Cream II: octyl salicylate, oxybenzone, avobenzone, and octinoxate.

Investigation of calcium silicate as a natural clay-based sunblock: Formulation and characterization

BACKGROUND

Sunlight exposure causes several types of health issues to humans, and in particular, it affects especially the skin. Among the most common harmful issues developed by UV exposure are erythema, pigmentation, and lesions in DNA, which may lead to cancer. These long-term effects can be minimized with the use of sunscreen.

OBJECTIVE

The use of commercial UV filters causes severe side effects such as skin allergy and whitening of the skin. Therefore, in this study the effectiveness of Ca₂ SiO₄ , a compound abundantly present in the soils of certain South Asian regions, has been the first time explored as UV filter. This compound leaves a low amount of white residue on the skin and is highly stable.

METHOD

The comparative study of a cosmetic formulation having 5% Ca₂ SiO₄ , and other formulations containing 5% TiO₂ and 5% ZnO as inorganic UV filters, was performed to evaluate the physical and chemical stability.

RESULT

The zeta potential and chemical stability of formulations containing these different UV filters were investigated by using UV-Vis spectroscopy, FTIR-ATR, and X-ray diffraction. Results indicated Ca₂ SiO₄ as a promising innovative UV filter with an SPF value of 37.94. One of the reasons is its low interaction with organic filter, that is, PABA, as compared to commercial ZnO and TiO₂ inorganic UV filters. Biological absorption in organs was studied by ICP-MS on model mice.

CONCLUSION

It also has a low photocatalytic activity; thus, formation of radicals is minimum. Moreover, Ca₂ SiO₄ showed a recognized ability to leave a low amount of white residue on the skin combined with great stability.

Y2O3 decorated TiO2 nanoparticles: Enhanced UV attenuation and suppressed photocatalytic activity with promise for cosmetic and sunscreen applications

Nanoparticulate titanium dioxide (TiO₂) is widely used in cosmetic products and sunscreens. However, primarily due to their photocatalytic activity, some TiO₂ products have been shown to be cytotoxic. Thus, the aim of this study was to reduce the photoactivity and consequent cytotoxicity of TiO₂nanoparticles. As such, in this work, yttrium oxide (Y₂O₃) was deposited onto TiO₂, at 5% and 10% Y/Ti weight ratio, via a hydrothermal method. The nanocomposites produced, TiO₂@Y₂O₃ 5 and 10 wt%, were characterised to assess their physical, photochemical and toxicological properties. These materials exhibit a uniform yttria coating, enhanced UV attenuation in the 280-350 nm range and significantly reduced photoactivity compared with a pristine commercial TiO₂ sample (Degussa Aeroxide® P25). Furthermore, the comparative cytotoxicity and photo-cytotoxicity of these materials to a human keratinocyte cell line (HaCaT), was assessed using a colorimetric tetrazolium salt (MTS) assay. Following 24-hour incubation with cells, both Y₂O₃ loadings exhibited improved biocompatibility with HaCaT cells, compared to the pristine TiO₂ sample, under all subsequent test conditions. In conclusion, the results highlight the potential of these materials for use in products, applied topically, with sun protection in mind.

Materials Science Challenges in Skin UV Protection: A Review

UV radiation is one of the critical environmental stress factors for human skin, which can trigger various problems such as pruritus, burning, erythema, premature skin aging and skin cancer. Hence, UV protection has become an indispensable daily routine and the use of topical sunscreen products is rapidly increasing. However, there are emerging concerns over the efficiency and safety of existing chemical and physical UV filters used in consumer products. Furthermore, there is no universally approved method for assessing sun protection efficiency regardless of the immediate end user need to develop safer sunscreen products that afford broad-spectrum photoprotection. It is evident that the current organic and inorganic UV filters have significant unfavorable impacts on human, environmental, and marine safety. Therefore, effective alternative UV filters should be established. This article comprehensively reviews the properties, safety, health and ecological concerns of various UV filters including TiO₂ and ZnO nanoparticles as well as the limitations of the testing protocols and guidelines provided by major regulatory bodies. The photoreactivity of UV filters used in sunscreen remains a major challenge, and it is crucial to develop new sunscreen ingredients, which not only protect the consumer, but also the environment.

Sunscreen protection factor enhancement through supplementation with Rambutan (Nephelium lappaceum L) ethanolic extract

The use of plant bioactives in cosmetic formulations are increasing due to the search for new sustainable sources of raw materials, greater concern for safety and possible social impacts caused by the incorrect use of natural resources. Plant extracts have been the subject of several studies in several industrial areas. However, the potential use of tropical fruits extracts in cosmetic formulations remains largely unexplored. Considering the impact on public health and the possibility of using wastes from fruit processing, the aim of this work is to identify, evaluate and develop a sunscreen based on rambutan peel extracts (Nephelium lappaceum L) as a natural additive for enhancing the final product sun protection factor (SPF). The phytochemical screening revealed the presence of tannins and flavonoids and the absence of coumarins. Even presenting a low sunscreen factor when used alone (SPF value 0.4), rambutan extract at 1.00% FTP concentration improved the photoprotective result (11.2) of the formulation containing 7.5% of ethylhexyl metoxycinnamate (EHMC) by 134%. The addition of rambutan extract in the formulation shows the potential to reduce the use of synthetic photoprotectors by about 64% of the total synthetic organic filters used to achieve the SPF value of 26.3. In addition, the sunscreen formulation supplemented with rambutan extract containing 1.00% RTP shows the potential to minimize the risk of synthetic agent toxicity and a 45% reduction in the cost of sunscreen production.

Aqueous aging of a silica coated TiO2 UV filter used in sunscreens: investigations at the molecular scale with dynamic nuclear polarization NMR

Short-term, aqueous aging of a commercial nanocomposite TiO₂ UV filter with a protective SiO₂ shell was examined in abiotic simulated fresh- and seawater. Under these conditions, the SiO₂ layer was quantitatively removed (∼88–98%) within 96 hours, as determined using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). While these bulk ICP-AES analyses suggested almost identical SiO₂ shell degradation after aging in fresh- and seawater, surface sensitive ²⁹Si dynamic nuclear polarization (DNP) solid-state nuclear magnetic resonance (SSNMR), with signal enhancements of 5–10× compared to standard SSNMR, was able to distinguish differences in the aged nanocomposites at the molecular level. DNP-SSNMR revealed that the attachment of the silica layer to the underlying TiO₂ core rested on substantial Si–O–Ti bond formation, bonds which were preserved after freshwater aging, yet barely present after aging in seawater. The removal of the protective SiO₂ layer is due to ionic strength accelerated dissolution, which could present significant consequences to aqueous environments when the photoactive TiO₂ core becomes exposed. This work demonstrates the importance of characterizing aged nanocomposites not only on the bulk scale, but also on the molecular level by employing surface sensitive techniques, such as DNP-NMR. Molecular level details on surface transformation and elemental speciation will be crucial for improving the environmental safety of nanocomposites.

Short-term, aqueous aging of a commercial nanocomposite TiO₂ UV filter with a protective SiO₂ shell was examined in abiotic simulated fresh- and seawater.

Sunscreen products: Rationale for use, formulation development and regulatory considerations

The association of sunrays with skin damage have been known since medieval times. The description of the electromagnetic spectrum facilitated the identification of the ultraviolet light spectrum as being responsible for skin damage resulting from prolonged skin exposure. Sunscreens have been used since ancient civilizations with various measures to limit exposure to sun exposure being employed. Awareness of the risks associated with sunrays has been increasing in the last century, and as a result, the science, technologies, and formulation have advanced significantly. The use of sunscreen products continues rising as government health agencies seek to contain increasing cases of UV induced melanomas. Recreational sunbathing and artificial tanning have increased the risk for these diseases significantly. This review article sought to expound the scientific basis of sunscreen use, the classification, formulation, quality control and regulation across the different countries around the world. The literature review was conducted on Google scholar, PubMed, SCOPUS, Cochrane, BMJ, SCIELO among others.

Assessment of the cytotoxicity and genotoxicity of homosalate in MCF-7

BACKGROUND

UV filters should be determined a strict toxicological safety prior to approval. Homosalate (HMS) is one of the most widely used organic UV filter. HMS accumulates in aquatic biota ecosystems and humans through the food chain; therefore, it is important to consider the effects on health and know its mechanisms of action.

AIMS

The study aimed to evaluate the cytotoxic and genotoxic effects of HMS in MCF-7 cell line.

METHODS

Cell viability was examined by the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide (MTT) and cell membrane integrity by the lactate dehydrogenase release assays (LDH), and genotoxicity by using the micronucleus test at 250, 500, 750, 1000, 1500, and 2000 µM concentrations with the human breast cell line MCF-7.

RESULTS

Homosalate affected the cell viability dose-dependently at a concentrations of above 1000 µM. Micronucleus formation was significantly induced at 750 and 1000 µM within 24 hours due to an increase in cytostatic effect, the cell viability of HMS decreased to 57% at a concentration of 2000 µM, and a sufficient number of binucleated cells could not be obtained to count. Homosalate was also clastogenic when the cells were incubated at cytotoxic concentrations.

CONCLUSION

These results suggest that homosalate can be considered as a cytotoxic and genotoxic substance.

Spherical Composite Powder by Coupling Polymethyl Methacrylate and Boron Nitride via Spray Drying for Cosmetic Application

In the present study, spherical composite powder was successfully prepared via spray drying process using polymethyl methacrylate (PMMA) and hexagonal boron nitride (h-BN) powders. The pristine and as-prepared composite powders were examined using scanning electron microscopy, a particle size analyzer, oil absorption, and specific surface area analyses. These powders were then mixed with linseed oil to prepare samples for UV-Visible-Near Infrared spectroscopy investigation to determine their light absorption ability. Blank and powder-added blemish balm creams were examined using a sun protection factor tester and a thermal conductivity tester. In addition, transmittances of these creams were also evaluated. The experimental results show that spray-dried spherical composite powder exhibited good oil absorption ability. The blemish balm cream with 10 wt.% spray-dried composite powder not only exhibited superior sunscreen protection ability, but also good thermal conductivity.

Synthesis of hyaluronic acid or O-carboxymethyl chitosan-stabilized ZnO–ginsenoside Rh2 nanocomposites incorporated with aqueous leaf extract of Dendropanax morbifera Léveille: in vitro studies as potential sunscreen agents

Synthesis of Rh2–ZnO nanocomposites stabilized with hyaluronic acid or O-carboxymethyl chitosan.

Ultrafast sonochemistry-based approach to coat TiO2 commercial particles for sunscreen formulation

TiO₂ is a common inorganic filter used in sunscreens due to its photoprotective effect on the skin against UV radiation. However, the use of this kind of material in cosmetics is limited by its inherent photocatalytic activity. It is known that coating on TiO₂ surface can improve some features. Although, many of the methodologies used for this purpose are still laborious and time-consuming. Thus, this work reports a novel, easy, cheap and fast strategy to coat TiO₂ particles by using a sonochemistry approach, aiming to decrease photocatalytic activity and to enhance colloidal stability. For this proposal, SiO₂, Al₂O₃, ZrO₂ and sodium polyacrylate (PAANa) were used to tune the surface of commercial TiO₂ particles and they were applied in a sunscreen formulation. The samples were characterized by XRPD, FT-IR, DLS, EDS, SEM and TEM. The photocatalytic activity and UV-shielding ability were also evaluated. The sunscreen formulations were prepared and characterized by zeta potential, DLS, and Sun Protection Factor (SPF). FT-IR, EDS, and charge surface of the particles confirmed the success of the sonochemistry coating. Additionally, TiO₂@Al₂O₃, TiO₂@SiO₂ and TiO₂@PAANa show a lower photocatalytic activity than original TiO₂ with similar UV-shielding ability. The sunscreens produced with the coated TiO₂ have similar SPF to the one with commercial TiO₂. Specifically, the sunscreen with TiO₂@PAANa shows an increase in colloidal stability. Herein, the incorporation of the sonochemical-coated TiO₂ particles in sunscreen formulations may produce sunscreens with better aesthetic appearance and a greater health security due to its lower free radicals production.

Multifunctional Moth-Eye TiO2/PDMS Pads with High Transmittance and UV Filtering

This work reports a facile fabrication method for constructing multifunctional moth-eye TiO₂/polydimethylsiloxane (PDMS) pads using soft nano-imprinting lithography and a gas-phase-deposited thin sacrificial layer. Mesoporous TiO₂ nanoparticles act as an effective UV filter, completely blocking high-energy UVB light and partially blocking UVA light and forming a robust TiO₂/PDMS composite pad by allowing the PDMS solution to easily fill the porous TiO₂ network. The paraboloid-shaped moth-eye nanostructures provided high transparency in the visible spectrum and also have self-cleaning effects because of nanoroughness on the surface. Furthermore, we successfully achieved a desired multiscale-patterned surface by partially curing select regions using TiO₂/PDMS pads with partial UVA ray blockers. The ability to fabricate multifunctional polymeric pads is advantageous for satisfying increasing demands for flexible and wearable electronics, displays, and solar cells.

The Effects of UV Light on the Chemical and Mechanical Properties of a Transparent Epoxy-Diamine System in the Presence of an Organic UV Absorber

Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV) damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR) analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM) imaging. Additionally, the glass transition temperatures (T_g) before and during UV radiation were measured. After an 800 h UV radiation, mechanical test results revealed that the lack of the UV absorber can lead to a ~30% reduction in tensile strength. However, in the presence of Tinuvin 1130, the tensile strength was reduced only by ~11%. It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light.

Formation and Controlled Growth of Bismuth Titanate Phases into Mesoporous Silica Nanoparticles: An Efficient Self-Sealing Nanosystem for UV Filtering in Cosmetic Formulation

The application of nanosized inorganic UV filters in cosmetic field is limited by their high photocatalytic properties that could induce the degradation or dangerous transformation of the organic molecules in sunscreen formulations. To overcome this problem and simultaneously enlarge the window of filter's absorption, we propose the growth of bismuth titanates Bi_xTi_yO_z into mesoporous silica nanoparticles (MSN). We investigated the chemical-physical properties by means of XRPD, TEM, UV-vis spectroscopy, N₂ physisorption, XPS, and SF-ICP-MS analysis, while the influence on the environment was evaluated through photocatalytic tests. The growing process of this new nanosystem is discussed underlining the key role of the Bi³⁺ ion that, acting as a low-melting point agent for the silica framework, led to a self-sealing mechanism. The excellent UV shielding properties combined with a radical suppression of the photocatalytic activity make the proposed nanosystem a perfect candidate for the development of the next generation nanomaterials for sunscreen formulations.

Plant-based active photoprotectants for sunscreens

Excessive exposure to the sun's radiation is the major exogenous mediator of skin damage, which accelerates skin ageing and increases the risk of developing skin cancer. Compounds with photoprotectant activity are extremely useful for decreasing the effect of ultraviolet (UV) radiation on the skin; however, numerous sun filters, especially organic sunscreens, are allergenic. Therefore, the development of formulations containing plant extracts, which may be potentially safer, is extensively being explored. Plant-based cosmetics are commonly used to avoid skin ageing because they contain antioxidant agents that minimize free radical activity, and numerous studies have investigated the skin-protectant effects of related plant species. In addition to their antioxidant properties, plant-based cosmetics protect the skin against solar radiation because they contain polyphenols such as flavonoids and carotenoids. Therefore, this study aims to present a review of plant species commonly used in sunscreens to protect the skin against damage due to sunlight exposure.

Are sunscreens a new environmental risk associated with coastal tourism?

The world coastal-zone population and coastal tourism are expected to grow during this century. Associated with that, there will be an increase in the use of sunscreens and cosmetics with UV-filters in their formulation, which will make coastal regions worldwide susceptible to the impact of these cosmetics. Recent investigations indicate that organic and inorganic UV-filters, as well as many other components that are constituents of the sunscreens, reach the marine environment--directly as a consequence of water recreational activities and/or indirectly from wastewater treatment plants (WWTP) effluents. Toxicity of organic and inorganic UV filters has been demonstrated in aquatic organism. UV-filters inhibit growth in marine phytoplankton and tend to bioaccumulate in the food webs. These findings together with coastal tourism data records highlight the potential risk that the increasing use of these cosmetics would have in coastal marine areas. Nevertheless, future investigations into distribution, residence time, aging, partitioning and speciation of their main components and by-products in the water column, persistence, accumulation and toxicity in the trophic chain, are needed to understand the magnitude and real impact of these emerging pollutants in the marine system.