The Tiny Big Difference: Nanotechnology in Photoprotective Innovations - A Systematic Review.

UV radiation causes long- and short-term skin damage, such as erythema and skin cancer. Therefore, the use of sunscreens is extremely important. However, concerns about UV filter safety have prompted exploration into alternative solutions, with nanotechnology emerging as a promising avenue. This systematic review identified 23 experimental studies utilizing nanocarriers to encapsulate sunscreens with the aim of enhancing their efficacy and safety. Polymeric and lipid nanoparticles are frequently employed to encapsulate both organic and inorganic UV filters along with natural antioxidants. Nanocarriers have demonstrated benefits including reduced active ingredient usage, increased sun protection factor, and mitigated photoinstability. Notably, they also decreased the skin absorption of UV filters. In summary, nanocarriers represent a viable strategy for improving sunscreen formulations, offering enhanced physicochemical properties and bolstered photoprotective effects, thereby addressing concerns regarding UV filter safety and efficacy in cosmetic applications.

Photoprotection-related properties of a raw extract from Gordonia hongkongensis EUFUS-Z928: A culturable rare actinomycete associated with the Caribbean octocoral Eunicea fusca.

UV filters in current sunscreen formulations can have negative effects on human health, such as endocrine disruption and allergic reactions, as well as on the environment, including bioaccumulation and coral health toxicity. As a result, there is a need to find alternative compounds that serve as safer and more ecofriendly active ingredients. This study successfully isolated actinomycetes from the octocoral Eunicea fusca and assessed their potential as producers of photoprotective compounds. The use of bio-based chemical agents, particularly natural products, has been a highly effective strategy for discovering bioactive compounds, especially in marine invertebrates and their associated microbiota. Eighteen bacterial isolates were obtained and subsequently employed to prepare raw methanolic extracts from seven-day submerged cultures in Zobell marine broth. The resulting extracts were screened for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity and characterized by total phenolic and flavonoid content measurements. After screening, the Gordonia hongkongensis EUFUS-Z928-derived raw extract exhibited the best antioxidant profile, i.e. DPPH and ABTS radical scavenging of 4.93 and 6.00 µmol Trolox per gram of extract, respectively, and selected for further photoprotection-related analysis. Thus, this extract demonstrated a UV-absorbing capacity of 46.33% of the in vitro sun protection factor calculated for 30 µg/mL oxybenzone but did not exhibit any cytotoxicity on human dermal fibroblasts (HDFa cell line) at concentrations up to 500 µg/mL. The liquid chromatography-mass spectrometry chemical characterization of this extract showed compounds with structural features associated with free radical scavenging and UV absorption (i.e. photoprotection-related activities). These findings highlighted the potential of the microbiota associated with E. fusca and confirmed the feasibility of exploiting its metabolites for photoprotection-related purposes.

Computer-aided drug design supporting sunscreen research: a showcase study using previously synthesized hybrid UV filter-antioxidant compounds.

CONTEXT: Although quantum mechanical calculations have proven effective in accurately predicting UV absorption and assessing the antioxidant potential of compounds, the utilization of computer-aided drug design (CADD) to support sustainable synthesis research of new sunscreen active ingredients remains an area with limited exploration. Furthermore, there are ongoing concerns about the safety and effectiveness of existing sunscreens. Therefore, it remains crucial to investigate photoprotection mechanisms and develop enhanced strategies for mitigating the harmful effects of UVR exposure, improving both the safety and efficacy of sunscreen products. A previous study conducted synthesis research on eight novel hybrid compounds (I-VIII) for use in sunscreen products by molecular hybridization of trans-resveratrol (RESV), avobenzone (AVO), and octinoxate (OMC). Herein, time-dependent density functional theory (TD-DFT) calculations performed in the gas phase on the isolated hybrid compounds (I-VIII) proved to reproduce the experimental UV absorption. Resveratrol-avobenzone structure-based hybrids (I-IV) present absorption maxima in the UVB range with slight differences between them, while resveratrol-OMC structure-based hybrids (V-VIII) showed main absorption in the UVA range. Among RESV-OMC hybrids, compounds V and VI exhibited higher UV absorption intensity, and compound VIII stood out for its broad-spectrum coverage in our simulations. Furthermore, both in silico and in vitro analyses revealed that compounds VII and VIII exhibited the highest antioxidant activity, with compound I emerging as the most reactive antioxidant within RESV-AVO hybrids. The study suggests a preference for the hydrogen atom transfer (HAT) mechanism over single-electron transfer followed by proton transfer (SET-PT) in the gas phase. With a strong focus on sustainability, this approach reduces costs and minimizes effluent production in synthesis research, promoting the eco-friendly development of new sunscreen active ingredients. METHODS: The SPARTAN'20 program was utilized for the geometry optimization and energy calculations of all compounds. Conformer distribution analysis was performed using the Merck molecular force field 94 (MMFF94), and geometry optimization was carried out using the parametric method 6 (PM6) followed by density functional theory (DFT/B3LYP/6-31G(d)). The antioxidant behavior of the hybrid compounds (I-VIII) was determined using the highest occupied molecular orbital (εHOMO) and the lowest unoccupied molecular orbital (εLUMO) energies, as well as the bond dissociation enthalpy (BDE), ionization potential (IP), and proton dissociation enthalpy (PDE) values, all calculated at the same level of structural optimization. TD-DFT study is carried out to calculate the excitation energy using the B3LYP functional with the 6-31G(d) basis set. The calculated transitions were convoluted with a Gaussian profile using the Gabedit program.

Prospecting toxicity of the avobenzone sunscreen in plants.

Avobenzone (AVO) is a sunscreen with high global production and is constantly released into the environment. Incorporating sewage biosolids for fertilization purposes, the leaching from cultivated soils, and the use of wastewater for irrigation explain its presence in the soil. There is a lack of information about the impact of this sunscreen on plants. In the present study, the ecotoxicity of AVO was tested at concentrations 1, 10, 100, and 1,000 ng/L. All concentrations caused a reduction in root growth of Allium cepa, Cucumis sativus, and Lycopersicum esculentum seeds, as well as a mitodepressive effect, changes in the mitotic spindle and a reduction in root growth of A. cepa bulbs. The cell cycle was disturbed because AVO disarmed the enzymatic defense system of root meristems, leading to an accumulation of hydroxyl radicals and superoxides, besides lipid peroxidation in cells. Therefore, AVO shows a high potential to cause damage to plants and can negatively affect agricultural production and the growth of non-cultivated plants.

An important step towards the comprehensive sun protection: Blue-light exposure inhibits DNA repair in reconstituted human skin and a broadband sunscreen avoids this inhibition.

The field of sun protection is quickly changing and the research article by Douki et al., published in the current issue of Photochemistry and Photobiology, reported key experimental data that will certainly help the development of better sun care products. Mutagenic photoproducts (CPDs, cyclobutane pyrimidine dimers and 6-4PPs, pyrimidine-6-4-pyrimidone photoproducts) were formed in the reconstructed human epidermis (RHE) by UVB (312 nm) irradiation, and their concentrations were detected by HPLC-MS/MS as a function of time after the UVB treatment. RHE had been previously exposed or not (control) to blue light (427 nm). Both CPDs and 6-4PPs were shown to last longer in blue-light irradiated RHE, proving the inhibition of the DNA repair by blue light exposure. This is a highly relevant information because sunscreens allow people to enjoy longer periods under the sun and consequently, to endure very high doses of blue light. The work also reported results obtained with RHEs previously treated with a sunscreen formulation containing a broadband filter that offers blue-light protection. Interestingly, authors observed that the DNA repair was not significantly inhibited in RHE previously treated with the sunscreen offering broadband protection. Readers will find a scientifically sound proof of the importance of blue-light protection in sun care products.

Ecotoxicological assessment of UV filters benzophenone-3 and TiO2 nanoparticles, isolated and in a mixture, in developing zebrafish (Danio rerio).

The increasing use of UV filters, such as benzophenone-3 (BP-3) and titanium dioxide nanoparticles (TiO2 NPs), has raised concerns regarding their ecotoxicological effects on the aquatic environment. The aim of the present study was to examine the embryo-larval toxicity attributed to BP-3 or TiO2 NPs, either alone or in a mixture, utilizing zebrafish (Danio rerio) as a model after exposure to environmentally relevant concentrations of these compounds. Zebrafish embryos were exposed to BP-3 (10, 100, or 1000 ng/L) or TiO2 NPs (1000 ng/L) alone or in a mixture (BP-3 10, 100, or 1000 ng/L plus 1000 ng/L of TiO2 NPs) under static conditions for 144 hr. After exposure, BP-3 levels were determined by high-performance liquid chromatography (HPLC). BP-3 levels increased in the presence of TiO2 NPs, indicating that the BP-3 degradation decreased in the presence of the NPs. In addition, in the presence of zebrafish, BP-3 levels in water decreased, indicating that zebrafish embryos and larvae might absorb BP-3. Data demonstrated that, in general, environmentally relevant concentrations of BP-3 and TiO2 NPs, either alone or in a mixture, did not significantly induce changes in heart and spontaneous contractions frequencies, levels of reactive oxygen species (ROS), morphological and morphometric parameters as well as mortality rates during 144 hr exposure. However, the groups exposed to TiO2 NPs alone and in a mixture with BP-3 at 10 ng/L exhibited an earlier significant hatching rate than the controls. Altogether, the data indicates that a potential ecotoxicological impact on the aquatic environment exists.

Photoaging and cosmeceutical solutions in sun-overexposed countries: The experience of Australia and Brazil.

Skin aging is the result of physiological changes determined by genetically driven processes and intrinsic factors, and exacerbated by a combination of multiple environmental factors, the main one being sun exposure. The effects of photoaging are particularly apparent on the face, where the appearance of aging signs can have a significant impact on the emotions conveyed and well-being. Photoprotection and facial skin care for managing photoaging signs are thus of particular importance for both physical and mental health. Countries, like Australia and Brazil, where the level of sun exposure is high and the populations have predominantly outdoor lifestyles, are particularly aware of the harms of photoaging and have implemented several measures to help reduce the risk of skin cancer in their populations. However, sun-seeking behaviours are difficult to change, and it takes time before interventions provide perceptible results. Australia still has some of the highest skin cancer incidence and mortality rates in the world. Solutions that target individuals can also be used for minimizing the clinical signs of facial aging and for improving skin quality, with the ultimate aim being not only to improve the appearance of the skin but also to mitigate the occurrence of pre-malignant and malignant lesions. This review summarizes the features of facial skin photoaging in photo-exposed populations, based on evidence gained from studies of Australian individuals, and discusses the various available solutions for skin photoaging, in particular those that are most popular in Brazil, which is a country with many years of experience in managing photoaged skin.

Analysis of the UV filter Benzophenone-3 assimilation in Crossostrea gigas oysters post-exposure in a controlled environment by LC-MS/MS.

Benzophenone-3 (BP-3), utilized as a UV filter in cosmetic products, is an emerging contaminant that constitutes a threat to natural resources and environmental health. This study investigated the assimilation of the UV filter BP-3 in Crassostrea gigas oysters collected in Florianópolis, Santa Catarina, Brazil. Lyophilized oyster tissue extracts were prepared using the QuEChERS method, and LC-MS/MS was employed to determine the BP-3 concentration in the samples. The method was applied to specimens intentionally exposed to two concentrations of the contaminant, for different periods of exposure (1 and 7 days). Samples from treatment 1 (T1) were exposed to a concentration of 1 µg L-1 of the BP-3 standard, and samples from treatment 2 (T2) were exposed to a concentration of 100 µg L-1 of the BP-3 standard. The results revealed rapid absorption of BP-3, with an increase of 126% for lower concentrations, reaching 1.13 µg of BP-3 per gram of oyster tissue, and 17% for higher concentrations, reaching 34.6 µg of BP-3 per gram of oyster tissue after 7 days. The presence of BP-3 even in samples not directly exposed to the contaminant indicates its widespread environmental distribution. The rapid bioaccumulation suggests the need to consider seasonal variations, such as increased tourism in the summer. The validated analytical method demonstrated efficacy in quantifying BP-3, providing an integrated approach for long-term monitoring of pollution levels and their dynamic variations over time. In addition, variation in BP-3 levels in the samples may be related to transport patterns influenced by tides and discharges from septic system, highlighting the need to improve wastewater treatment. These findings underscore the necessity for continuous biomonitoring and effective environmental management to safeguard the health of marine ecosystems and humans.

The use of natural extracts with photoprotective activity: a 2015-2023 patent prospection.

Synthetic sunscreen offers protection against excessive exposure to ultraviolet (UV) radiation from the sun, and protects the skin from possible damage. However, they have low efficacy against the formation of reactive oxygen species (ROS), which are highly reactive molecules that can be generated in the skin when it is exposed to UV radiation, and are known to play a role in oxidative stress, which can contribute to skin aging and damage. Thus, there is an ongoing search for sunscreens that do not have these negative effects. One promising source for these is natural products. Therefore, the current patent review summarizes topical formulations made from natural compounds that have antioxidant properties and can be used as photoprotective or anti-aging agents, either using a single natural extract or a combination of extracts. The review reports basic patent information (applicant country, type of applicant, and year of filing) and gives details about the invention, including its chemical composition, and the in vitro and in vivo tests performed. These patents describe natural products that can be used to protect the skin and validate their efficacy, and safety, in addition to standardizing their formulations. The compositions described illustrate the consistent innovation in the use of natural products to protect against UV damage and photoaging disorders, a promising field which is receiving growing global recognition.

Female offspring of mice perinatally exposed to benzophenone-3 showed early subfertility linked to a poor oocyte stockpile.

Previously, we found that the ultraviolet filter benzophenone-3 (BP3) causes fetal growth restriction in mice when is applied when implantation occurs (first week of gestation). However, whether BP3 can affect gestation and fertility after implantation period is unknown. We aimed to study the effects on reproductive physiology of the offspring caused by perinatal exposure to BP3. C57BL/6 pregnant mice were dermally exposed to 50 mg BP3/kg bw.day or olive oil (vehicle) from gestation day 9 (gd9) to postnatal day 21 (pnd1). We observed no differences in mother's weights, duration of gestation, number of pups per mother, onset of puberty or sex ratio. The weights of the pups exposed to benzophenone-3 were transiently lower than those of the control. Estrous cycle was not affected by perinatal exposure to BP3. Besides, we performed a fertility assessment by continuous breeding protocol: at 10 weeks of age, one F1 female and one F1 male mouse from each group was randomly chosen from each litter and housed together for a period of 6 months. We noticed a reduction in the number of deliveries per mother among dams exposed to BP3 during the perinatal period. To see if this decreased fertility could be associated to an early onset of oocytes depletion, we estimated the ovarian reserve of germ cells. We found reduced number of oocytes and primordial follicles in BP3. In conclusion, perinatal exposure to BP3 leads to a decline in the reproductive capacity of female mice in a continuous breeding protocol linked to oocyte depletion.

In vitro blastocyst implantation and trophoblast migration are disrupted by the UV filter benzophenone-3 (BP3).

Benzophenone-3 (BP3) is a common ingredient in personal care products (PCPs) due to its well-established effectiveness in absorbing UV radiation. Sunscreen products are among the most widely used PCPs-containing BP3 applied to the skin, resulting in significant human exposure to BP3 primarily through a dermal application. In the present work, we have tested the action of three environmentally relevant concentrations of BP3 (2, 20 and 200 µg/L) on an in vitro model of implantation of murine blastocysts and on migration ability of the human trophoblast cell line Swan 71. We showed that BP3 caused a significant reduction of blastocyst expansion and a delayed hatching in a non-monotonic way. Besides, embryos displayed a delayed attachment in the three BP3 groups, resulting in a smaller implantation area on the 6th day of culture: BP3(2) (0.32 ± 0.07 mm2); BP3(20) (0.30 ± 0.08 mm2) and BP3(200) (0.25 ± 0.06 mm2) in comparison to the control (0.42 ± 0.07 mm2). We also found a reduced migration capacity of the human first-trimester trophoblast cell line Swan 71 in a scratch assay when exposed to BP3: the lowest dose displayed a higher uncovered area (UA) at 6h when compared to the control, whereas a higher UA of the wound was observed for the three BP3 concentrations at 18 and 24 h of exposure. The changes in UA provoked by BP3 restored to normal values in the presence of flutamide, an androgen receptor (AR) inhibitor. These results indicate that a direct impairment on early embryo implantation and a defective migration of extravillous trophoblast cells through the androgen receptor pathway can be postulated as mechanisms of BP3-action on early gestation with potential impact on fetal growth.

In vitro Safety Assessment of Extracts and Compounds From Plants as Sunscreen Ingredients.

This work investigated the safety of extracts obtained from plants growing in Colombia, which have previously shown UV-filter/antigenotoxic properties. The compounds in plant extracts obtained by the supercritical fluid (CO2) extraction method were identified using gas chromatography coupled to mass spectrometry (GC/MS) analysis. Cytotoxicity measured as cytotoxic concentration 50% (CC50) and genotoxicity of the plant extracts and some compounds were studied in human fibroblasts using the trypan blue exclusion assay and the Comet assay, respectively. The extracts from Pipper eriopodon and Salvia aratocensis species and the compound trans-ß-caryophyllene were clearly cytotoxic to human fibroblasts. Conversely, Achyrocline satureioides, Chromolaena pellia, and Lippia origanoides extracts were relatively less cytotoxic with CC50 values of 173, 184, and 89 µg/mL, respectively. The C. pellia and L. origanoides extracts produced some degree of DNA breaks at cytotoxic concentrations. The cytotoxicity of the studied compounds was as follows, with lower CC50 values representing the most cytotoxic compounds: resveratrol (91 µM) > pinocembrin (144 µM) > quercetin (222 µM) > titanium dioxide (704 µM). Quercetin was unique among the compounds assayed in being genotoxic to human fibroblasts. Our work indicates that phytochemicals can be cytotoxic and genotoxic, demonstrating the need to establish safe concentrations of these extracts for their potential use in cosmetics.

Long-term maintenance treatment of rosacea: experts' opinion.

BACKGROUND: Rosacea is a chronic inflammatory dermatosis characterized by remissions and flares. Although the rosacea active treatment phase is well established, the long-term maintenance phase is still challenging. OBJECTIVE: To discuss and make recommendations on how to treat patients during the long-term maintenance phase for the main rosacea phenotypes. METHODS: A panel of six board-certified Brazilian dermatologists and one American dermatologist gathered to compose a consensus based upon an initial statement on how to treat rosacea during the long-term maintenance phase based on the methodology Nominal Group Technique. The experts discussed each factor based upon an initial statement on how to treat rosacea patients in the long-term maintenance phase. A sequence of comprehensive narrative reviews was performed; a questionnaire preparation about the definition of the maintenance phase and its management was presented; an interpersonal discussion and ranking of the ideas were conducted. Recommendations were made if the specialists had 75% agreement. RESULTS: The maintenance treatment phase, which starts by achieving IGA 0 or 1 grades at the active phase, should be considered at least during the 9-month period after remission. The recommendations of all treatments target this period. Daily skincare regimen and sunscreen are crucial. Active treatment phase should be recommended if signs or symptoms reappear or worsen. CONCLUSION: Maintenance phase success depends on patient's adherence to daily skin care, appropriate treatments, continued follow-up with dermatologist, and self-assessment to identify new signs and symptoms indicating disease relapse.

Assessment of the photoprotective potential and structural characterization of secondary metabolites of Antarctic fungus Arthrinium sp.

Interest in Antarctic fungi has grown due to their resilience in harsh environments, suggesting the presence of valuable compounds from its organisms, such as those presenting photoprotective potential, since this environment suffers the most dangerous UV exposure in the world. Therefore, this research aimed to assess the photoprotective potential of compounds from sustainable marine sources, specifically seaweed-derived fungi from Antarctic continent. These studies led to discovery of photoprotective and antioxidant properties of metabolites from Arthrinium sp., an endophytic fungus from Antarctic brown algae Phaeurus antarcticus. From crude extract, fractions A-I were obtained and compounds 1-6 isolated from E and F fractions, namely 3-Hydroxybenzyl alcohol (1), (-)-orthosporin (2), norlichexanthone (3), anomalin B (4), anomalin A (5), and agonodepside B (6). Compounds 1, 2, and 6 were not previously reported in Arthrinium. Fraction F demonstrated excellent absorbance in both UVA and UVB regions, while compound 6 exhibited lower UVB absorbance, possibly due to synergistic effects. Fraction F and compound 6 displayed photostability and were non-phototoxic to HaCaT cells. They also exhibited antioxidant activity by reducing intracellular ROS production induced by UVA in keratinocyte monolayers and reconstructed human skin models (resulting in 34.6% and 30.2% fluorescence reduction) and did not show irritation potential in HET-CAM assay. Thus, both are promising candidates for use in sunscreens. It is noted that Fraction F does not require further purification, making it advantageous, although clinical studies are necessary to confirm its potential applicability for sunscreen formulations.

Benzophenone-3 sunscreen causes phytotoxicity and cytogenotoxicity in higher plants.

The benzophenone-3 (BP-3) sunscreen is recurrently released into the environment from different sources, however, evaluations of its adverse effects on plants do not exist in the literature. In this study, BP-3 was evaluated, at concentrations 2; 20, and 200 µg/L, regarding phytotoxicity, based on germination and root elongation in seeds, in Lactuca sativa L., Cucumis sativus L. and Allium cepa L., and phytotoxicity, cytogenotoxicity and oxidative stress in A. cepa bulb roots. The BP-3 concentrations, except for the 200 µg/L concentration in L. sativa, caused no significant reduction in seed germination. All concentrations tested significantly reduced the elongation of roots from seeds and roots from bulbs. The 20 and 200 µg/L concentrations caused oxidation in cells, disturbances in the cell cycle, and alterations in prophase and metaphase, as well as the induction of micronuclei, in A. cepa root meristems. Furthermore, the three concentrations induced a high number of prophases in root tips. Such disorders were caused by excess H2O2 and superoxide produced in cells due to exposure to BP-3, which triggered significant phytotoxicity, cytotoxicity, and genotoxicity in root meristems. Thus, the recurrent contamination of agricultural and non-agricultural soils with BP-3, even at a concentration of 2 µg/L, represents an environmental risk for plants. These results point to the impending need to set limits for the disposal of this sunscreen into the environment since BP-3 has been used in industry for several decades.

Photoprotective and antigenotoxic properties of Cutibacterium acnes ecotypes native to terrestrial subsurface habitats.

Actinobacteria are known to produce a variety of secondary metabolites with skin-protective properties. This study aimed to investigate the photoprotective and antigenotoxic properties against UVB of extracts obtained from Cutibacterium acnes strains. Bacterial growth was measured spectrophotometrically and the constant maximum growth rate (µ) value to each strain, were calculated. In vitro photoprotection efficacy was evaluated using in vitro indices such as sun protection factor (SPFespectrophotometric) and critical wavelength (λc). UVB-antigenotoxicity was also evaluated using the SOS Chromotest. Correlation analysis was used to examine the relationship between SPFespectrophotometric and extract concentration and the %GI estimates. Among the studied strains, one showed low (6.0 ≤ SPFespectrophotometric ≤ 14.9) and eight showed media (15.0 ≤ SPFespectrophotometric ≤ 29.9) UVB photoprotection efficacy. All of them resulted in broad-spectrum (UVA-UVB) photoprotection (λc > 370 nm). In total, two C. acnes ecotypes with different growth rates were evidenced, but the protective metabolites in the extracts were produced without the influence of growth rate. Photoprotective efficacy depended on the extract concentration and was correlated with antigenotoxicity. We demonstrated that C. acnes extracts can be used as sunscreen ingredients that reduce UVB-induced genotoxicity.

Effects of Commercial Sunscreens on Survival, Reproduction and Embryonic Development of the Aquatic Snail Biomphalaria glabrata (SAY, 1818).

Over the past few years, there has been a significant increase in the use of sunscreens. Consequently, the occurrence in aquatic environments of ultraviolet filters has also increased. The present study aims to evaluate the toxicity of two commercial sunscreens to the aquatic snail Biomphalaria glabrata. Acute assays were performed with adult snails exposed to solutions of the two products in synthetic soft water. Reproduction and development assays were carried out, involving individual adult and egg masses exposure to assess fertility and embryonic development. Sunscreen A showed a LC50-96 h of 6.8 g/L and reduction in number of eggs and egg masses per individual in the concentration of 0.3 g/L. Sunscreen B presented higher malformation rates in 0.4 g/L with 63% of malformed embryos. Results indicate that the formulation used in sunscreens is an important factor in aquatic toxicity and needs to be evaluated before the final product is commercialized.

Effect of TiO2 Microparticles in Lettuce (Lactuca sativa L.) Seeds and Seedlings.

The particle size reduction technology is used in several segments, including sunscreens and new techniques and product improvement. One of the main particles used in the sunscreens formulation is titanium dioxide (TiO2). This formulation allows for better characteristics of these products. Perspectives like incorporation of the particles by other biological systems beyond humans and their effects should be observed. This work aimed to evaluate the titanium dioxide microparticles phytotoxicity on Lactuca sativa L. plants through tests of germination, growth, and weight analysis using microscopy techniques: optical microscopy (OM) and scanning electron microscopy (SEM). Some of the results showed cellular and morphological damage, mainly in the roots and 50 mg L-1 TiO2 concentration, confirmed by SEM. Additionally, anatomical damages like vascular bundle disruption and irregularity in the cortex cells were confirmed by SEM. Additionally, anatomical damages were observed on the three main organs (root, hypocotyl, and leaves) evidenced by the OM. Perspectives to confirm new hypotheses of the interaction of nanomaterials with biological systems are necessary.

Analysis of sunscreens and antibiotics in groundwater during the Covid-19 pandemic in the Riviera Maya, Mexico.

Tourism contributes to groundwater pollution, but quantifying its exact impact is challenging due to the presence of multiple pollution sources. However, the COVID-19 pandemic presented a unique opportunity to conduct a natural experiment and assess the influence of tourism on groundwater pollution. One such tourist destination is the Riviera Maya in Quintana Roo, Mexico (specifically Cancun). Here, water contamination occurs due to the addition of sunscreen and antibiotics during aquatic activities like swimming, as well as from sewage. In this study, water samples were collected during the pandemic and when tourists returned to the region. Samples were taken from sinkholes (cenotes), beaches, and wells then tested using liquid chromatography for antibiotics and active ingredients found in sunscreens. The data revealed that contamination levels from specific sunscreens and antibiotics persisted even when tourists were absent, indicating that local residents significantly contribute to groundwater pollution. However, upon the return of tourists, the diversity of sunscreen and antibiotics found increased, suggesting that tourists bring along various compounds from their home regions. During the initial stages of the pandemic, antibiotic concentrations were highest, primarily due to local residents incorrectly using antibiotics to combat COVID-19. Additionally, the research found that tourist sites had the greatest contribution to groundwater pollution, with sunscreen concentration increasing. Furthermore, installation of a wastewater treatment plant decreased overall groundwater pollution. These findings enhance our understanding of the pollution contributed by tourists in relation to other pollution sources.

Development of Photoprotective Formulations: Influence of Formulation Composition on the SPF and Mechanical Properties.

The evaluation of the vehicle formulation is important during the development of sunscreens, as it influences their efficacy. In this context, the aim of the present study was to develop photoprotective formulations and evaluate the influence of the formulation components in the sun protection factor (SPF) and physical-mechanical and sensory properties of the formulations. We evaluated four sunscreens through a 22 full factorial design in terms of concentration and emulsifier type. The design of experiments (DOE) parameters were SPF, thixotropy, and work of shear. After the screening of the formulations by DOE, the SPF values, mechanical and sensory properties, and stability were evaluated. All study formulations showed non-Newtonian pseudoplastic behavior, compatible with sunscreens, and presented SPF values above 30. The factors evaluated in DOE had significant interactions for all the analyzed parameters. The concentration of the phosphate-based emulsifier influenced the SPF parameter. The work of shear was influenced by the concentration of polyglyceryl-based emulsifier. The concentration and the type of emulsifier influenced the thixotropy. Finally, effective sunscreens were developed, and the type and concentration of emulsifiers had an influence on the SPF of the formulations. In addition, the formulations chosen by DOE were stable and showed good sensory properties.