Chemical oxidation and DNA damage catalysed by inorganic sunscreen ingredients

Use of Cosmetics in Pregnancy and Neurotoxicity: Can It Increase the Risk of Congenital Enteric Neuropathies?

Pregnancy is a particularly vulnerable period for the growing fetus, when exposure to toxic agents, especially in the early phases, can decisively harm embryo development and compromise the future health of the newborn. The inclusion of various chemical substances in personal care products (PCPs) and cosmetic formulations can be associated with disruption and damage to the nervous system. Microplastics, benzophenones, parabens, phthalates and metals are among the most common chemical substances found in cosmetics that have been shown to induce neurotoxic mechanisms. Although cosmetic neurotoxin exposure is believed to be minimal, different exposure scenarios of cosmetics suggest that these neurotoxins remain a threat. Special attention should be paid to early exposure in the first weeks of gestation, when critical processes, like the migration and proliferation of the neural crest derived cells, start to form the ENS. Importantly, cosmetic neurotoxins can cross the placental barrier and affect the future embryo, but they are also secreted in breast milk, so babies remain exposed for longer periods, even after birth. In this review, we explore how neurotoxins contained in cosmetics and PCPs may have a role in the pathogenesis of various neurodevelopmental disorders and neurodegenerative diseases and, therefore, also in congenital enteric aganglionosis as well as in postnatal motility disorders. Understanding the mechanisms of these chemicals used in cosmetic formulations and their role in neurotoxicity is crucial to determining the safety of use for cosmetic products during pregnancy.

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.

Comprehensive Analysis of Titanium Oxide Nanoparticle Size and Surface Properties on Neuronal PC-12 Cells: Unraveling Cytotoxicity, Dopaminergic Gene Expression, and Acetylcholinesterase Inhibition

Titanium oxide nanoparticles can penetrate the blood-brain barrier, infiltrate the central nervous system, and induce neurotoxicity. One of the most often utilized nanoparticles has been investigated for their neurotoxicity in many studies. Nonetheless, there remains an unexplored aspect regarding the comparative analysis of particles varying in size and nanoparticles of identical dimensions, both with and devoid of surface coating. In the current study, we synthesized two differently sized nanoparticles, TiO2-10 (10 nm) and TiO2-22 (22 nm), and nanoparticles of the same size but with a polyvinylpyrrolidone surface coating (TiO2-PVP, 22 nm) and studied their toxic effects on neural PC-12 cells. The results highlighted significant dose- and time-dependent cytotoxicity at concentrations ≥10 μg/mL. The exposure of TiO2 nanoparticles significantly elevated reactive oxygen and nitrogen species levels, IL-6 and TNF-α levels, altered the mitochondrial membrane potential, and enhanced apoptosis-related caspase-3 activity, irrespective of size and surface coating. The interaction of the nanoparticles with acetylcholinesterase enzyme activity was also investigated, and the results revealed a dose-dependent suppression of enzymatic activity. However, the gene expression studies indicated no effect on the expression of all six genes associated with the dopaminergic system upon exposure to 10 μg/mL for any nanoparticle. The results demonstrated no significant difference between the outcomes of TiO2-10 and TiO2-22 NPs. However, the polyvinylpyrrolidone surface coating was able to attenuate the neurotoxic effects. These findings suggest that as the TiO2 nanoparticles get smaller (towards 0 nm), they might promote apoptosis and inflammatory reactions in neural cells via oxidative stress, irrespective of their size.

The Enigmatic World of Fungal Melanin: A Comprehensive Review

Synthetic dyes are generally not safe for human health or the environment, leading to the continuous search and growing demand for natural pigments that are considered safer, biodegrade more easily, and are environmentally beneficial. Among micro-organisms, fungi represent an emerging source of pigments due to their many benefits; therefore, they are readily viable on an industrial scale. Among all the bioactive pigments produced by fungi, melanin is an enigmatic, multifunctional pigment that has been studied for more than 150 years. This dark pigment, which is produced via the oxidative polymerization of phenolic compounds, has been investigated for its potential to protect life from all kingdoms, including fungi, from biotic and abiotic stresses. Over time, the research on fungal melanin has attracted a significant amount of scientific interest due to melanin's distinct biological activities and multifarious functionality, which is well-documented in the literature and could possibly be utilized. This review surveys the literature and summarizes the current discourse, presenting an up-to-date account of the research performed on fungal melanin that encompasses its types, the factors influencing its bioactivity, the optimization of fermentation conditions to enhance its sustainable production, its biosynthetic pathways, and its extraction, as well as biochemical characterization techniques and the potential uses of melanin in a wide range of applications in various industries. A massive scope of work remains to circumvent the obstacles to obtaining melanin from fungi and exploring its future prospects in a diverse range of applications.

Surface Coating of Titanium Dioxide Nanoparticles with a Polymerizable Chelating Agent and Its Physicochemical Property

Surface modification of inorganic nanoparticles is critical for the quality and performance of pigments, cosmetics, and composite materials. We covered the titanium dioxide nanoparticles' surface with 2-(acetoacetoxy) ethyl methacrylate, a polymerizable chelating agent. Through the in situ polymerization procedure, this molecule's β-ketoester moiety quickly coordinated with the metal atoms on titanium dioxide nanoparticles, and its methacrylate group formed homogeneous coating layers. This coating layer significantly reduced the photocatalytic activity of titanium dioxide nanoparticles and prevented their aggregation. This nanoparticle dispersion showed low viscosity up to the solid content of 60% (w/w) in the liquid dispersant. As a result, it increased the UV screening performance and dispersion stability. Additionally, this coating layer widened the absorption spectrum of titanium dioxide and could change the color of nanoparticles from pale yellow to brown. It can also be helpful for cosmetic applications.

Application and mechanisms of metal-based nanoparticles in the control of bacterial and fungal crop diseases

Nanotechnology is a young branch of the discipline generated by nanomaterials. Its development has greatly contributed to technological progress and product innovation in the field of agriculture. The antimicrobial properties of nanoparticles (NPs) can be used to develop nanopesticides for plant protection. Plant diseases caused by bacterial and fungal infestations are the main types of crop diseases. Once infected, they will seriously threaten crop growth, reduce yield and quality, and affect food safety, posing a health risk to humans. We reviewed the application of metal-based nanoparticles in inhibiting plant pathogenic bacteria and fungi, and discuss the antibacterial mechanisms of metal-based nanoparticles from two aspects: the direct interaction between nanoparticles and pathogens, and the indirect effects of inducing plant resilience to disease. © 2022 Society of Chemical Industry.

Uptake of nanoparticles from sunscreen physical filters into cells arising from increased environmental microwave radiation: increased potential risk of the use of sunscreens to human health

This study examines the microwave chemical risks posed by photocatalysts present in sunscreens (physical filters) against the increasing use of microwaves (radio waves) in the environment, sometimes referred to as electronic smog. Specifically, the study assesses the damage caused by silica-coated physical filters (photocatalysts, TiO_2⋅ and/or ZnO) contained in commercially available sunscreens and fresh silica-coated ZnO for sunscreens to mouse skin fibroblasts cells (NIH/3T3) evaluated in vitro by the life/death of cells using two types of electromagnetic waves: UV light and microwave radiation, and under simultaneous irradiation with both UV light and microwaves. Conditions of the electromagnetic waves were such as to be of lower light irradiance than that of UVA/UVB radiation from incident sunlight, and with microwaves near the threshold power levels that affect human health. The photocatalytic activity of the physical filters was investigated by examining the degradation of the rhodamine B (RhB) dye in aqueous media and by the damage caused to DNA plasmids from E. coli. Compared to the photocatalytic activity of ZnO and TiO₂ when irradiated with UV light alone, a clear enhanced photocatalytic activity was confirmed upon irradiating these physical filters concurrently with UV and microwaves. Moreover, the uptake of these metal oxides into the NIH/3T3 cells led to the death of these cells as a result of the enhanced photocatalytic activity of the metal oxides on exposure to microwave radiation.

Titanium Dioxide: Structure, Impact, and Toxicity

Titanium dioxide, first manufactured a century ago, is significant in industry due to its chemical inertness, low cost, and availability. The white mineral has a wide range of applications in photocatalysis, in the pharmaceutical industry, and in food processing sectors. Its practical uses stem from its dual feature to act as both a semiconductor and light scatterer. Optical performance is therefore of relevance in understanding how titanium dioxide impacts these industries. Recent breakthroughs are summarised herein, focusing on whether restructuring the surface properties of titanium dioxide either enhances or inhibits its reactivity, depending on the required application. Its recent exposure as a potential carcinogen to humans has been linked to controversies around titanium dioxide's toxicity; this is discussed by illustrating discrepancies between experimental protocols of toxicity assays and their results. In all, it is important to review the latest achievements in fast-growing industries where titanium dioxide prevails, while keeping in mind insights into its disputed toxicity.

What's next in the use of opacifiers for cosmetic coatings of solid dosage forms? Insights on current titanium dioxide alternatives

The consolidated use of coatings containing E171 (i.e. titanium dioxide, TiO2) as an opacifier has made the white color of the resulting dosage forms a quality standard in the pharmaceutical and dietary supplement fields. This color is also associated with the efficiency of the coating layer in protecting the substrate from the effects of UV rays. However, health risks related to diet exposure to TiO2 has recently been advanced and its addition in coating formulations has been seriously questioned. As a consequence, in principle safer TiO2-free formulations have been recently launched on the market, especially for coatings of dietary supplements. In this work, we evaluated the overall physico-technological characteristics and performance of immediate release tablets coated with a variety of commercial cosmetic formulations free of E171. Moreover, a quantitative method based on the CIELab color space was proposed for the first time for studying the covering/coloring performance of the coating formulations. Based on the results obtained, the possibility to achieve a satisfactory covering capability and a degree of white comparable to that of a standard TiO2-containing reference with all the commercially-available ready-to-use TiO2-free products considered, without affecting the dissolution performance, was demonstrated.

Environmental Fate and Toxicity of Sunscreen-Derived Inorganic Ultraviolet Filters in Aquatic Environments: A Review

An increasing number of inorganic ultraviolet filters (UVFs), such as nanosized zinc oxide (nZnO) and titanium dioxide (nTiO2), are formulated in sunscreens because of their broad UV spectrum sunlight protection and because they limit skin damage. However, sunscreen-derived inorganic UVFs are considered to be emerging contaminants; in particular, nZnO and nTiO2 UVFs have been shown to undergo absorption and bioaccumulation, release metal ions, and generate reactive oxygen species, which cause negative effects on aquatic organisms. We comprehensively reviewed the current study status of the environmental sources, occurrences, behaviors, and impacts of sunscreen-derived inorganic UVFs in aquatic environments. We find that the associated primary nanoparticle characteristics and coating materials significantly affect the environmental behavior and fate of inorganic UVFs. The consequential ecotoxicological risks and underlying mechanisms are discussed at the individual and trophic transfer levels. Due to their persistence and bioaccumulation, more attention and efforts should be redirected to investigating the sources, fate, and trophic transfer of inorganic UVFs in ecosystems.

Amorphous and crystalline cerium(IV) phosphates: biocompatible ROS-scavenging sunscreens

This paper reports on a comprehensive study of the UV-shielding properties (namely, the sun protection factor and the factor of protection against UV-A radiation) and cytotoxicity (including photocytotoxicity) of amorphous and crystalline cerium(IV) phosphates. It has been shown that cerium(IV) phosphate NH₄Ce₂(PO₄)₃ is characterised by UV-shielding properties that are comparable to those of nanocrystalline TiO₂ and CeO₂. Moreover, cerium(IV) phosphates did not show toxicity towards cell cultures of NCTC L929 line mouse fibroblasts and human mesenchymal stem cells, in a wide range of concentrations, and even enhanced the proliferative activity of the latter. In a model study of the photoprotective properties of cerium(IV) phosphates on human mesenchymal stem cells, the pronounced protective effect of NH₄Ce₂(PO₄)₃ was observed, which was comparable to the shielding action of nanocrystalline CeO₂. The results have shown that tetravalent cerium phosphates can be considered as promising UV-filters for sunscreen applications.

Plant-derived nanotherapeutic systems to counter the overgrowing threat of resistant microbes and biofilms

Since antiquity, the survival of human civilization has always been threatened by the microbial infections. An alarming surge in the resistant microbial strains against the conventional drugs is quite evident in the preceding years. Furthermore, failure of currently available regimens of antibiotics has been highlighted by the emerging threat of biofilms in the community and hospital settings. Biofilms are complex dynamic composites rich in extracellular polysaccharides and DNA, supporting plethora of symbiotic microbial life forms, that can grow on both living and non-living surfaces. These enforced structures are impervious to the drugs and lead to spread of recurrent and non-treatable infections. There is a strong realization among the scientists and healthcare providers to work out alternative strategies to combat the issue of drug resistance and biofilms. Plants are a traditional but rich source of effective antimicrobials with wider spectrum due to presence of multiple constituents in perfect synergy. Other than the biocompatibility and the safety profile, these phytochemicals have been repeatedly proven to overcome the non-responsiveness of resistant microbes and films via multiple pathways such as blocking the efflux pumps, better penetration across the cell membranes or biofilms, and anti-adhesive properties. However, the unfavorable physicochemical attributes and stability issues of these phytochemicals have hampered their commercialization. These issues of the phytochemicals can be solved by designing suitably constructed nanoscaled structures. Nanosized systems can not only improve the physicochemical features of the encapsulated payloads but can also enhance their pharmacokinetic and therapeutic profile. This review encompasses why and how various types of phytochemicals and their nanosized preparations counter the microbial resistance and the biofouling. We believe that phytochemical in tandem with nanotechnological innovations can be employed to defeat the microbial resistance and biofilms. This review will help in better understanding of the challenges associated with developing such platforms and their future prospects.

Antimicrobial effect of radiant catalytic ionization

The main purpose of micro-organisms elimination from the air and surfaces is to ensure microbiological safety in health care facilities or food production plants. Currently, many disinfection methods are used, both physical, chemical and, increasingly, biological. Scientists seek new solutions with high antimicrobial effectiveness (especially against the drug-resistant strains of bacteria), low production and operating costs, and, above all, the safety of patients and food consumers. The limitation of the methods used so far is primarily the micro-organisms acquire the resistance, mainly to antimicrobial agents. One of the new and alternative methods of disinfection is radiant catalytic ionization (RCI). RCI is an active method of air and surface purification. The technology proved high efficiency against viruses, Gram-positive and -negative bacteria, and fungi, both in the air and on surfaces (planktonic forms and biofilm). RCI has many advantages as well as some minor limitations. This overview summarizes the current knowledge about RCI technology.

Oxygen vacancy assisted condensation of DNA molecule observed on ZnO thin film

An exotic condensation of DNA molecules is observed on the nanostructured ZnO surface. The ZnO nanostructures (NS) fabricated by thermal vapor deposition technique were associated with a large number of oxygen vacancies on the surface. These oxygen vacancies induced changes in the DNA conformation which further reflected through changes in the persistence length of the DNA molecules. This indicates a reinforcement of the bonds and binding in both the phosphate and the base regions of the DNA molecules with the positively charged core vacancy sites on the ZnO nanostructured surface through strong interaction mediated via long-range electrostatic forces which effectively reduced the end-to-end distance of the λ-DNA molecule. This strongly suggests a transition of the λ-DNA molecule through structural modification into a more compact higher-order fractal dimension from its native state.

Combat of antimicrobial resistance in municipal wastewater treatment plant effluent via solar advanced oxidation processes: Achievements and perspectives

This review aims to gather main achievements and limitations associated to the application of solar photocatalytic processes with regard to the removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from municipal wastewater treatment plant effluent (MWWTPE). Solar photocatalytic processes were chosen considering the context of developing tropical countries. Among these processes, solar photo-Fenton has been proved effective for the elimination of ARB from MWWTPE at neutral pH in bench and pilot scale and also under continuous flow. Yet, ARG removal varies as according to the gene. Irradiation intensity and matrix composition play a key role on treatment efficiency for this purpose. The use of sulfate radical in modified solar photo-Fenton is still incipient for ARB and ARG removal. Also, investigations related to ARB resistance profile and horizontal gene transfer rates after solar photo-Fenton treatment must be further analyzed. Regarding solar heterogeneous photocatalysis, TiO₂ and TiO₂-composites applied in suspension are the most commonly investigated for the removal of ARB and ARGs. Irradiation intensity, temperature and catalyst dosage affect treatment efficiency. However, most studies were performed in synthetic solutions using reduced sample volumes. Extended exposition times and addition of H₂O₂ to the system (solar/TiO₂/H₂O₂) are required to prevent bacteria regrowth and ensure ARG abatement. In addition, enhancement of TiO₂ with graphene or (semi)metals improved ARB elimination. Differences concerning irradiation intensity, matrix composition, catalyst dosage, and model ARB and ARGs used in studies analyzed in this review hinder the comparison of photocatalysts synthesized by various research groups. Finally, future research should aim at evaluating the efficiency of solar photocatalytic processes in real matrices originated from sewage treatment systems applied in developing countries; determining indicators of antimicrobial resistance in MWWTPE; and investigating ARB mutation rate as well as the removal of cell-free ARGs present in suspension in MWWTPE.

Ecotoxicological effects of new generation pollutants (nanoparticles, amoxicillin and white musk) on freshwater and marine phytoplankton species

Phytoplankton occupies a key trophic level in aquatic ecosystems. Chemical impacts on these primary producers can disrupt the integrity of an entire ecosystem. Two freshwater (Pseudokirchneriella subcapitata-Ps and Scenedesmus obliquus-S) and three marine (Phaeodactylum tricornutum-P, Isochrysis galbana-I, Tetraselmis suecica-T) microalgae species were exposed to dilutions of four chemicals: nanoparticles (n-TiO₂, n-ZnO), amoxicillin (antibiotic), and white musk (personal care fragrance) to determine the half maximal effective concentration (EC₅₀) after 72 h of exposure under standardized and controlled environmental conditions. Cell cultures were exposed to EC₅₀ to determine sublethal effects (72 h) based on biochemical (chlorophylls a, b, c), molecular (changes in outer cell wall structure), and morphological alterations. We report for the first time EC₅₀ values for nanoparticles in not standardized species (S, I and T) and for amoxicillin and white musk in all tested species. Standardized species (Ps and P) were less sensitive than non-standardized in some cases. Fourier-transformed infrared spectroscopy showed a marked spectral alteration (from 10.44% to 90.93%) of treated cultures compared to negative controls; however, principal component analysis disclosed no differences in molecular alteration between the five microalgae species or the two aquatic habitats considered. There was a significant decrease in chlorophylls content in all species exposed to EC₅₀ compared to controls (Kruskal Wallis test; p < 0.05). There was a significant increase in cell-size (Mann-Whitney U test; p < 0.05) in I, P and T exposed to white musk and S exposed to amoxicillin. Findings highlight ecotoxicological risks from new generation pollutants for primary producers in aquatic ecosystems.

Nanoparticles from the Cosmetics and Medical Industries in Legal and Environmental Aspects

This paper presents the application and role of nanomaterials, with particular emphasis on the cosmetics and medical industries. Methods of obtaining materials at the nanoscale and their characteristic structure, which determines their attractiveness and risk, especially in recent years, have been described. The subject of the work was to indicate the hazards and risks that are associated with the properties of nanomaterials; dimension, and high chemical and physical activity, thus making ways to capture and monitor them difficult. Legal and environmental aspects were taken into account, and the involvement of the European Commission in this subject and the activities carried out in a few European countries as well as in Japan, the USA and Canada were analyzed.

Microbial melanin: Recent advances in biosynthesis, extraction, characterization, and applications

Melanin is a common name for a group of biopolymers with the dominance of potential applications in medical sciences, cosmeceutical, bioremediation, and bioelectronic applications. The broad distribution of these pigments suggests their role to combat abiotic and biotic stresses in diverse life forms. Biosynthesis of melanin in fungi and bacteria occurs by oxidative polymerization of phenolic compounds predominantly by two pathways, 1,8-dihydroxynaphthalene [DHN] or 3,4-dihydroxyphenylalanine [DOPA], resulting in different kinds of melanin, i.e., eumelanin, pheomelanin, allomelanin, pyomelanin, and neuromelanin. The enzymes responsible for melanin synthesis belong mainly to tyrosinase, laccase, and polyketide synthase families. Studies have shown that manipulating culture parameters, combined with recombinant technology, can increase melanin yield for large-scale production. Despite significant efforts, its low solubility has limited the development of extraction procedures, and heterogeneous structural complexity has impaired structural elucidation, restricting effective exploitation of their biotechnological potential. Innumerable studies have been performed on melanin pigments from different taxa of life in order to advance the knowledge about melanin pigments for their efficient utilization in diverse applications. These studies prompted an urgent need for a comprehensive review on melanin pigments isolated from microorganisms, so that such review encompassing biosynthesis, bioproduction, characterization, and potential applications would help researchers from diverse background to understand the importance of microbial melanins and to utilize the information from the review for planning studies on melanin. With this aim in mind, the present report compares conventional and modern ideas for environment-friendly extraction procedures for melanin. Furthermore, the characteristic parameters to differentiate between eumelanin and pheomelanin are also mentioned, followed by their biotechnological applications forming the basis of industrial utilization. There lies a massive scope of work to circumvent the bottlenecks in their isolation and structural elucidation methodologies.

Resistance of multidrug resistant Escherichia coli to environmental nanoscale TiO2 and ZnO

Excessive production and utilization of nanoparticles (NPs) at industrial and household levels releases substantial quantities of NPs into the environment. These can be harmful to different types of organisms and cause adverse effects on ecosystems. Purchased TiO₂ and ZnO NPs were characterized via XRD, XPS, FESEM, and Zeta potential. This study elucidates how multidrug resistant Escherichia coli LM13, which was recovered from livestock manure, counteracts the antibacterial activities of TiO₂ and ZnO NPs to survive in the environment. E. coli ATCC25922, which is susceptible to antibiotics, was used as control. A dose-response experiment showed that the antibacterial activity of TiO₂ was lower than that of ZnO NPs and, LM13 was more resistant to NPs than ATCC25922. An AcrAB-TolC efflux pump along with its regulation genes helped LM13 to minimize NP toxicity. Flow cytometry findings also indicated that the intensity of the side-scatter light parameter increased with TiO₂ and ZnO NPs in a dose dependent manner, suggesting NP uptake by the both strains. The generation of reactive oxygen species in LM13 was several-fold lower than in ATCC25922, suggesting that reactive oxygen species mainly contribute to the toxicity mechanism. These results illustrate the necessity to evaluate the impacts of NPs on the survival capacity of bacteria and on the resistance genes in bacteria with higher NP resistance than NP susceptible bacteria.

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.

Toxicological Consequences of Titanium Dioxide Nanoparticles (TiO2NPs) and Their Jeopardy to Human Population

Titanium dioxide nanoparticles (TiO2 NPs) are the most produced nanomaterial for food additives, pigments, photocatalysis, and personal care products. These nanomaterials are at the forefront of rapidly developing indispensable nanotechnology. In all these nanomaterials, titanium dioxide (TiO2) is the most common nanomaterial which is being synthesized for many years. These nanoparticles of TiO2 are widely used at the commercial level, especially in cosmetic industries. High usage in such a way has increased the toxicological consequences of the human population. Several studies have shown that TiO2 NPs accumulated after oral exposure or inhalation in the alimentary canal, lungs, heart, liver, spleen, cardiac muscle, and kidneys. Additionally, in mice and rats, they disturb glucose and lipid homeostasis. Moreover, TiO2 nanoparticles primarily cause adverse reactions by inducing oxidative stress that leads to cell damage, inflammation, genotoxicity, and adverse immune responses. The form and level of destruction are strongly based on the physical and chemical properties of TiO2 nanoparticles, which administer their reactivity and bioavailability. Studies give indications that TiO2 NPs cause both DNA strand breaks and chromosomal damages. The effects of genotoxicity do not depend only on particle surface changes, size, and exposure route, but also relies on the duration of exposure. Most of these effects may be because of a very high dose of TiO2 NPs. Despite increased production and use, epidemiological data for TiO2 NPs is still missing. This review discusses previous research regarding the impact of TiO2 NP toxicity on human health and highlights areas that require further understanding in concern of jeopardy to the human population. This review is important to point out areas where extensive research is needed; thus, their possible impact on individual health should be investigated in more details.

Are Titania Photocatalysts and Titanium Implants Safe? Review on the Toxicity of Titanium Compounds

Titanium and its compounds are broadly used in both industrial and domestic products, including jet engines, missiles, prostheses, implants, pigments, cosmetics, food, and photocatalysts for environmental purification and solar energy conversion. Although titanium/titania-containing materials are usually safe for human, animals and environment, increasing concerns on their negative impacts have been postulated. Accordingly, this review covers current knowledge on the toxicity of titania and titanium, in which the behaviour, bioavailability, mechanisms of action, and environmental impacts have been discussed in detail, considering both light and dark conditions. Consequently, the following conclusions have been drawn: (i) titania photocatalysts rarely cause health and environmental problems; (ii) despite the lack of proof, the possible carcinogenicity of titania powders to humans is considered by some authorities; (iii) titanium alloys, commonly applied as implant materials, possess a relatively low health risk; (iv) titania microparticles are less toxic than nanoparticles, independent of the means of exposure; (v) excessive accumulation of titanium in the environment cannot be ignored; (vi) titanium/titania-containing products should be clearly marked with health warning labels, especially for pregnant women and young children; (vi) a key knowledge gap is the lack of comprehensive data about the environmental content and the influence of titania/titanium on biodiversity and the ecological functioning of terrestrial and aquatic ecosystems.

TiO2 Nanoparticles Caused DNA Damage in Lung and Extra-Pulmonary Organs Through ROS-Activated FOXO3a Signaling Pathway After Intratracheal Administration in Rats

Introduction

Because of the increased production and application of manufactured Nano-TiO₂ in the past several years, it is important to investigate its potential hazards. TiO₂ is classified by IARC as a possible human carcinogen; however, the potential mechanism of carcinogenesis has not been studied clearly. The present study aimed to investigate the mechanism of DNA damage in rat lung and extra-pulmonary organs caused by TiO₂nanoparticles.

Methods

In the present study, SD rats were exposed to Nano-TiO₂ by intratracheal injection at a dose of 0, 0.2, or 1 g/kg body weight. The titanium levels in tissues were detected by ICP-MS. Western blot was used to detect the protein expression levels. The DNA damage and oxidative stress were detected by comet assay and ROS, MDA, SOD, and GSH-Px levels, respectively.

Results

The titanium levels of the 1 g/kg group on day-3 and day-7 were significantly increased in liver and kidney as well as significantly decreased in lung compared to day-1. ROS and MDA levels were statistically increased, whereas SOD and GSH-Px levels were statistically decreased in tissues of rats in dose-dependent manners after Nano-TiO₂ treatment. PI3K, p-AKT/AKT, and p-FOXO3a/FOXO3a in lung, liver, and kidney activated in dose-dependent manners. The levels of DNA damage in liver, kidney, and lung in each Nano-TiO₂ treatment group were significantly increased and could not recover within 7 days. GADD45α, ChK2, and XRCC1 in liver, kidney, and lung of rats exposed to Nano-TiO₂ statistically increased, which triggered DNA repair.

Conclusion

This work demonstrated that Ti could deposit in lung and enter extra-pulmonary organs of rats and cause oxidative stress, then trigger DNA damage through activating the PI3K-AKT-FOXO3a pathway and then promoting GADD45α, ChK2, and XRCC1 to process the DNA repair.

Exposure to ZnO/TiO2 Nanoparticles Affects Health Outcomes in Cosmetics Salesclerks

Concerns about the effects of nanoparticles (NPs) on human health are being raised by researchers because the risks of nanocosmetics like sunscreen are unknown. We explored the association between urinary oxidative stress markers and exposure of cosmetics salesclerks to 20 cosmetics that might contain titanium dioxide (TiO₂)/zinc oxide (ZnO) NPs. We then recruited 40 cosmetics salesclerks and 24 clothing salesclerks and categorized them based on their exposure to ZnO and TiO₂ NPs. Nineteen and 15 samples met the EU definition for TiO₂ and ZnO nanomaterials, respectively. Participants with a higher co-exposure index of ZnO and TiO₂ NPs had a significantly higher base level of urinary 8-hydroxy-2′-deoxyguanosin (8-OHdG) concentrations than the lower co-exposure group (5.82 vs. 2.85 ng/mL, p < 0.001). After potential confounding factors had been adjusted for, the TiO₂ and ZnO NP co-exposure index was significantly positively associated with the urinary 8-OHdG base concentration (β = 0.308, 95% CI = 0.106 to 0.510) and the creatinine-adjusted concentration (β = 0.486, 95% CI = 0.017 to 0.954). Current evidence suggests that the likelihood of harm from using sunscreens containing nanoparticles might result in higher urinary 8-OHdG. However, our limited number and types of sample cosmetics might underestimate the risk.

Innovative Bio-Based Organic UV-A and Blue Light Filters from Meldrum's Acid

Faced with the ban of some organic UV filters such as octinoxate or avobenzone, especially in Hawaii, it became essential to offer new alternatives that are both renewable and safe for humans and the environment. In this context, a class of bio-based molecules displaying interesting UV filter properties and great (photo)stability has been developed from Meldrum's acid and bio-based and synthetic p-hydroxycinnamic acids, furans and pyrroles. Moreover, p-hydroxycinnamic acid-based Meldrum's derivatives possess valuable secondary activities sought by the cosmetic industry such as antioxidant and anti-tyrosinase properties. The evaluation of the properties of mixture of judiciously chosen Meldrum's acid derivatives highlighted the possibility to modulate secondary activity while maintaining excellent UV protection. Meldrum's acid derivatives are not only competitive when benchmarked against organic filters currently on the market (i.e., avobenzone), but they also do not exhibit any endocrine disruption activity.

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 Properties of Marl

The physicochemical and sunscreen properties of marl as a function of particle size were investigated. The research findings established that the marl under investigation consisted of more than 95% calcium carbonate (CaCO₃). The particles of marl inspected under a scanning electron microscope were calcite, which is the stable polymorph of CaCO₃, with a rhombohedral structure. The particle size classification by the sieving method showed that grinding using a ball mill could downsize the marl particles by 2 to 3 times, reaching below 15 µm on average. Marl particles showed a tendency to reflect ultraviolet A (UVA) rays rather than UVB rays and a possibility to steadily absorb both UVAII and UVAI. Finer particles obtained after a longer grinding process demonstrated higher efficacy regarding UV reflection and absorption properties. The 3 wt.% marl displayed a sun protection factor (SPF) value of 1 to 2. However, marl demonstrated a good ability to protect against radiation over a broad spectrum range with a critical wavelength above 370 nm. The addition of marl in the formulation containing avobenzone and octinoxate had a positive synergistic effect because the marl was able to increase the UV absorbance efficacy (based on the area under the curve (AUC) value) and SPF value of the cream. Furthermore, it was also discovered that the added marl powder could slow the decrease in UV protection efficacy of the products in terms of the AUC calculated from the absorbance profile after exposure to simulated UV rays with an amplitude range of 10 J/cm² to 40 J/cm² for 30 min, which was similar to the results obtained from octocrylene and bemotrizinol.

Neurotoxicity mediated by oxidative stress caused by titanium dioxide nanoparticles in human neuroblastoma (SH-SY5Y) cells

BACKGROUND

Titanium is widely used in biomedicine. Due to biotribocorrosion, titanium dioxide (TiO₂) nanoparticles (NPs) can be released from the titanium implant surface, enter the systemic circulation, and migrate to various organs and tissues including the brain. A previous study showed that 5 nm TiO₂ NPs reached the highest concentration in the brain. Even though TiO₂ NPs are believed to possess low toxicity, little is known about their neurotoxic effects. The aim of the study was to evaluate in vitro the effects of 5 nm TiO₂ NPs on a human neuroblastoma (SH-SY5Y) cell line.

METHODS

Cell cultures were divided into non-exposed and exposed to TiO₂ NPs for 24 h. The following were evaluated: reactive oxygen species (ROS) generation, apoptosis, cellular antioxidant response, endoplasmic reticulum stress and autophagy.

RESULTS

Exposure to TiO₂ NPs induced ROS generation in a dose dependent manner, with values reaching up to 10 fold those of controls (p < 0.001). Nrf2 nuclear localization and autophagy, also increased in a dose dependent manner. Apoptosis increased by 4- to 10-fold compared to the control group, depending on the dose employed.

CONCLUSIONS

Our results show that TiO₂ NPs cause ROS increase, induction of ER stress, Nrf2 cytoplasmic translocation to the nucleus and apoptosis. Thus, neuroblastoma cell response to TiO₂ NPs may be associated with an imbalance of the oxidative metabolism where endoplasmic reticulum-mediated signal pathway seems to be the main neurotoxic mechanism.

Investigating partitioning of free versus macrocycle bound guest into a model POPC lipid bilayer

We report on the permeation of free and macrocycle-bound avobenzone across a POPC lipid bilayer through combined neutron reflectometry experiments and molecular dynamics simulations. Results indicate that the p-phosphonated calix[8]arene macrocycle limits the avobenzone penetration into the upper leaflet of the membrane. Hence, it could serve as a useful vehicle for safer formulations.

We report on the permeation of free and macrocycle-bound avobenzone across a POPC lipid bilayer through combined neutron reflectometry experiments and molecular dynamics simulations.

Non-use of sunscreen among adults and the elderly in southern Brazil

Background

One of the main prevention methods against skin cancer is the use of sunscreen; however, incidence of this disease has not declined despite prevention campaigns.

Objective

Investigate the prevalence of non-use of sunscreen and its associated factors.

Method

A population-based cross-sectional study with individuals aged 18 years or over living in the urban area. Conducted between April and July of 2016. Participants were interviewed about socioeconomic, demographic, and behavioral questions. Non-use of sunscreen was considered as the outcome. For multivariate analysis, Poisson regression with robust adjustment for variance was used.

Results

Among the 1300 participants, prevalence of non-use of sunscreen was 38.2% (95% CI: 34.6–41.8). The variables independently associated with the outcome were male sex, older age, brown or black skin color, lower income, fewer years of education, no physical activity in leisure time, no medical consultations in the last year, and self-perception of health as regular or poor.

Study limitations

The prevalence may be underestimated by reports of more use of sunscreen than actually used, which could increase the figure in the outcome.

Conclusion

It was estimated that about four out of ten adults and elderly do not use sunscreen in this sample. Prevention strategies are needed to advance health policy and ensure that sun protection options are easily accessible.

Engineered nanomaterials: From their properties and applications, to their toxicity towards marine bivalves in a changing environment

As a consequence of their unique characteristics, the use of Engineered Nanomaterials (ENMs) is rapidly increasing in industrial, agricultural products, as well as in environmental technology. However, this fast expansion and use make likely their release into the environment with particular concerns for the aquatic ecosystems, which tend to be the ultimate sink for this type of contaminants. Considering the settling behaviour of particulates, benthic organisms are more likely to be exposed to these compounds. In this way, the present review aims to summarise the most recent data available from the literature on ENMs behaviour and fate in aquatic ecosystems, focusing on their ecotoxicological impacts towards marine and estuarine bivalves. The selection of ENMs presented here was based on the OECD's Working Party on Manufactured Nanomaterials (WPMN), which involves the safety testing and risk assessment of ENMs. Physical-chemical characteristics and properties, applications, environmental relevant concentrations and behaviour in aquatic environment, as well as their toxic impacts towards marine bivalves are discussed. Moreover, it is also identified the impacts derived from the simultaneous exposure of marine organisms to ENMs and climate changes as an ecologically relevant scenario.

Paving the Way for A Sustainable and Efficient SiO2/TiO2 Photocatalytic Composite

Although photocatalysis is an extraordinary and tremendously explored topic, there is a need to find new ways to encourage the production of composite materials that are economical, efficient and with limited environmental impact. Nanocatalysts may benefit from appropriate support material for many reasons. In this study, TiO2 was deposited on SiO2, so that the silica not only provides the macroscopic structure on which the TiO2 is formed, but it positively affects the photocatalytic activity as well. This is because of the greater specific surface area which favors the adsorption of pollutants near the photocatalyst, the higher amount of surface-adsorbed water and hydroxyl groups and the inhibition of the photogenerated electron-hole recombination. The choice of preparing the Ti-precursor starting from titanium shavings and to directly deposit TiO2 on micrometric-sized silica by a simple hydrothermal method highlights the process sustainability. The results showed that it is possible to produce a photocatalytic composite from secondary materials, exhibiting excellent photocatalytic properties, comparable to the pristine one, and opening the possibility for large-scale production.

Fueling a Hot Debate on the Application of TiO2 Nanoparticles in Sunscreen

Titanium is one of the most abundant elements in the earth's crust and while there are many examples of its bioactive properties and use by living organisms, there are few studies that have probed its biochemical reactivity in physiological environments. In the cosmetic industry, TiO2 nanoparticles are widely used. They are often incorporated in sunscreens as inorganic physical sun blockers, taking advantage of their semiconducting property, which facilitates absorbing ultraviolet (UV) radiation. Sunscreens are formulated to protect human skin from the redox activity of the TiO2 nanoparticles (NPs) and are mass-marketed as safe for people and the environment. By closely examining the biological use of TiO2 and the influence of biomolecules on its stability and solubility, we reassess the reactivity of the material in the presence and absence of UV energy. We also consider the alarming impact that TiO2 NP seepage into bodies of water can cause to the environment and aquatic life, and the effect that it can have on human skin and health, in general, especially if it penetrates into the human body and the bloodstream.

Photodegradation of DNA Induced by Modified Forms of Titanium Dioxide

The UV-induced photodegradation of supercoiled DNA in aqueous solution is accelerated in the presence of a suspension of TiO2 nanoparticles. While nearly all samples of TiO2 are active in this respect, they differ markedly according to (i) the crystal structure of the TiO2; (ii) the presence of an external oxide coating on the TiO2; (iii) the presence within the TiO2 of dopant transition metal ions. Thus anatase is more active than rutile; coated TiO2 is less active than uncoated TiO2; the presence of all transition metal ions except Cr(III) acts to enhance the activity of the TiO2. Only Cr(III) acts to protect the DNA from enhanced degradation, while Mo(VI) ions render the TiO2 highly aggressive. The relative behaviour of these modified forms of TiO2 towards DNA on UV excitation closely parallels that previously found in that towards a number of synthetic polymers. The mechanisms for the varyingactions of the pigments are discussed.

Uptake and Translocation of Styrene Maleic Anhydride Nanoparticles in Murraya exotica Plants As Revealed by Noninvasive, Real-Time Optical Bioimaging

This work reports the in vivo uptake and translocation of PNPs in the one-year grown terrestrial plant, Murraya exotica ( M. exotica), as investigated by two-photon excitation and time-resolved (TPE-TR) optical imaging with a large field of view (FOV, 32 × 32 mm²) in a noninvasive and real-time manner. The PNPs (⟨ R_h⟩ = 12 ± 4.5 nm) synthesized from poly(styrene- co-maleic anhydride) (SMA) were Eu-luminescence labeled (λ_L ≈ 617 nm). On exposing the roots of living M. exotica plants to the colloidal suspension of SMA PNPs at different concentrations, the spatiotemporal evolution of SMA PNPs along plant stems (60 mm in length) were monitored by TPE-TR imaging, which rendered rich information on the uptake and translocation of PNPs without any interference from the autofluorescence of the plant tissues. The TPE-TR imaging combined with the high-resolution anatomy revealed an intercell-wall route in the lignified epidermis of M. exotica plants for SMA PNP uptake and translocation, as well as the similar accumulation kinetics at different positions along the plant stems. We modeled the accumulation kinetics with Gaussian distribution to account for the trapping probability of a SMA PNP by the lignified cell walls, allowing the statistical parameters, the average trapping time ( t_m) and its variance (σ), to be derived for the quantification of the PNP accumulation in individual plants. The TPE-TR imaging and the analysis protocols established herein will be helpful in exploring the mechanism of plant-PNP interaction under physiological condition.

Gas chromatographic-mass spectrometric analysis of sunscreens and their effects on mice liver and kidney enzyme function

Background

Sunscreens are one of the most widely used products among cosmetics and personal care products. Recent studies have shown that some of sunscreen formulations may contain toxic, carcinogenic, or even nonallowed chemicals that may affect skin, cells, and hormones.

Materials and methods

This study aimed to develop and validate a method that allows the determination of sunscreen ingredients by gas chromatography-mass spectrometry (GC-MS). Analysis of original sunscreen products (n=5) from a licensed pharmacy and counterfeit sunscreen products (n=5) from local markets in Jordan was performed using GC-MS. pH stability of the sunscreen samples were also monitored under different storage temperatures. Topical application of sunscreens on mice skin was conducted to study their effects on liver and kidney enzymes' function.

Results

In terms of pH stability, there is a significant change in pH at different degrees of temperature between the products. Diethyl phthalate (DEP) was detected in two counterfeit products and was not mentioned on the ingredients' label. DEP was reported for its percutaneous absorption and systemic uptake in the literature. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly increased with a P<0.005 in some groups treated with original sunscreens under sun radiation. Creatinine showed a significant decrease in some groups treated with original and counterfeit sunscreens, while blood urea nitrogen (BUN) showed no differences.

Conclusion

This study presents a method that allows the scanning and profiling of sunscreen ingredients as well as investigates their stability, permeation, and toxicity. Profiling of sunscreen product, changing in pH stability, and analyzing kidney and liver enzymes' level would be of a great impact on products' safety and consumers' health.

Photocatalytic production of hydroxyl radicals by commercial TiO2 nanoparticles and phototoxic hazard identification

This study identifies the phototoxic potential of commercial titanium dioxide nanoparticles (TiO₂ NPs) used in sunscreens and consumer products by employing a tiered testing approach comprising physicochemical, in vitro and ex vivo tests. Our results revealed that all the test samples of TiO₂ NPs, varied in surface coating, crystallinity and primary particle size, produced hydroxyl radicals upon UVA photoexcitation as determined by electron spin resonance (ESR) spectroscopy. Their phototoxic potentials were assessed first by combining the validated 3T3 neutral red uptake phototoxicity test and red blood cell phototoxicity test and subsequently in ex vivo models of chick chorioallantoic membrane (CAM) and reconstructed human 3D skin model (H3D). Crystalline structure and particle size of TiO₂ NPs were found to exert a major influence on the photocatalytic activity and the associated phototoxic effects. Besides, a medium-sized sample with silica/alumina also exhibited high phototoxic potency with no obvious relevance to the enhanced hydroxyl radicals and lipidperoxidation. This effect might be taken place through the interaction of harmful metal ions released from the oxide coating. However, no phototoxicity was observed on a H3D skin model probably due to the lack of efficient percutaneous absorption of TiO₂ NPs. This study demonstrates the efficacy of a tiered testing strategy for identifying phototoxic hazards of TiO₂ NPs and suggests the need for a comprehensive assessment that takes account of the effects of different coating materials and potential interactions between multiple mechanisms.

Trade-offs in ecosystem impacts from nanomaterial versus organic chemical ultraviolet filters in sunscreens

Both nanoparticulate (nZnO and nTiO₂) and organic chemical ultraviolet (UV) filters are active ingredients in sunscreen and protect against skin cancer, but limited research exists on the environmental effects of sunscreen release into aquatic systems. To examine the trade-offs of incorporating nanoparticles (NPs) into sunscreens over the past two decades, we targeted endpoints sensitive to the potential risks of different UV filters: solar reactive oxygen production in water and disruption of zebrafish embryo development. First, we developed methodology to extract nanoparticles from sunscreens with organic solvents. Zebrafish embryos exposed to parts-per-million NPs used in sunscreens displayed limited toxicological effects; nZnO particles appeared to be slightly more toxic than nTiO₂ at the highest concentrations. In contrast, seven organic UV filters did not affect zebrafish embryogenesis at or near aqueous solubility. Second, to simulate potent photo-initiated reactions upon release into water, we examined methylene blue (MB) degradation under UV light. nTiO₂ from sunscreen caused 10 times faster MB loss than nZnO and approached the photocatalytic degradation rate of a commercial nTiO₂ photocatalysts (P25). Organic UV filters did not cause measurable MB degradation. Finally, we estimated that between 1 and 10 ppm of sunscreen NPs in surface waters could produce similar steady state hydroxyl radical concentrations as naturally occurring fluvic acids under sunlight irradiation. Incorporation of NPs into sunscreen may increase environmental concentrations of reactive oxygen, albeit to a limited extent, which can influence transformation of dissolved substances and potentially affect ecosystem processes.

Application of nanoparticles in percutaneous delivery of active ingredients in cosmetic preparations

Developments in nanotechnology have expanded novel nanoparticles for several applications, including cosmetic topical preparation. The aim of this article was to review recent literature on percutaneous delivery of cosmetics active ingredient by nanoparticles. The main focus here, is on lipid based nanoparticles since they are of great importance in skin cargo delivery and have vast application in current cosmetic formulations. Data were collected via electronic databases using MeSH keywords, including nanoparticles, lipid particles, cosmetic, dermal delivery and combinations of these words. According to literature nanoparticles play a major role in improving the usefulness of cosmetics. They are able to improve the physiochemical stability of the skin based cosmetic products. Based on data, lipid nanostructures can be added to current cosmetic formulations without any significant problem due to their physical stability and compatibility with other ingredients. However, due to their basically risky nature of nanoparticles, their risk assessment should be taken into consideration.

Biodistribution, Clearance, and Long-Term Fate of Clinically Relevant Nanomaterials

Realization of the immense potential of nanomaterials for biomedical applications will require a thorough understanding of how they interact with cells, tissues, and organs. There is evidence that, depending on their physicochemical properties and subsequent interactions, nanomaterials are indeed taken up by cells. However, the subsequent release and/or intracellular degradation of the materials, transfer to other cells, and/or translocation across tissue barriers are still poorly understood. The involvement of these cellular clearance mechanisms strongly influences the long-term fate of used nanomaterials, especially if one also considers repeated exposure. Several nanomaterials, such as liposomes and iron oxide, gold, or silica nanoparticles, are already approved by the American Food and Drug Administration for clinical trials; however, there is still a huge gap of knowledge concerning their fate in the body. Herein, clinically relevant nanomaterials, their possible modes of exposure, as well as the biological barriers they must overcome to be effective are reviewed. Furthermore, the biodistribution and kinetics of nanomaterials and their modes of clearance are discussed, knowledge of the long-term fates of a selection of nanomaterials is summarized, and the critical points that must be considered for future research are addressed.