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

Sono-processes: Emerging systems and their applicability within the (bio-)medical field

Sonochemistry, although established in various fields, is still an emerging field finding new effects of ultrasound on chemical systems and are of particular interest for the biomedical field. This interdisciplinary area of research explores the use of acoustic waves with frequencies ranging from 20 kHz to 1 MHz to induce physical and chemical changes. By subjecting liquids to ultrasonic waves, sonochemistry has demonstrated the ability to accelerate reaction rates, alter chemical reaction pathways, and change physical properties of the system while operating under mild reaction conditions. It has found its way into diverse industries including food processing, pharmaceuticals, material science, and environmental remediation. This review provides an overview of the principles, advancements, and applications of sonochemistry with a particular focus on the domain of (bio-)medicine. Despite the numerous benefits sonochemistry has to offer, most of the research in the (bio-)medical field remains in the laboratory stage. Translation of these systems into clinical practice is complex as parameters used for medical ultrasound are limited and toxic side effects must be minimized in order to meet regulatory approval. However, directing attention towards the applicability of the system in clinical practice from the early stages of research holds significant potential to further amplify the role of sonochemistry in clinical applications.

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.

Phototoxic or Photoprotective?-Advances and Limitations of Titanium (IV) Oxide in Dermal Formulations-A Review

The widespread role of titanium (IV) oxide (TiO₂) in many industries makes this substance of broad scientific interest. TiO₂ can act as both a photoprotector and photocatalyst, and the potential for its role in both applications increases when present in nanometer-sized crystals. Its sunlight-scattering properties are used extensively in sunscreens. Furthermore, attempts have been made to incorporate TiO₂ into dermal formulations of photolabile drugs. However, the propensity to generate reactive oxygen species (ROS) rendering this material potentially cytotoxic limits its role. Therefore, modifications of TiO₂ nanoparticles (e.g., its polymorphic form, size, shape, and surface modifications) are used in an effort to reduce its photocatalytic effects. This review provides an overview of the potential risks arising from and opportunities presented by the use of TiO₂ in skin care formulations.

Surface oxygen vacancy engineering on TiO2 (101) via ALD technology for simultaneously enhancing charge separation and transfer

Titanium oxide molecular layers containing extensive SOV content (11.4-16.2%) have been constructed on (101) TiO₂ nanotubes through a precisely controlled atomic layer deposition technique, in which the charge separation efficiency and surface charge transfer efficiency are increased to 28.2% and 89.0%, respectively, about 17 and 2 times those of the initial TiO₂ nanotubes.

Holistic Photoprotection, Broad Spectrum (UVA-UVB), and Biological Effective Protection Factors (BEPFs) from Baccharis antioquensis Hydrolysates Polyphenols

Overexposure to solar radiation has become an increasingly worrying problem due to the damage to the skin caused by ultraviolet radiation (UVR). In previous studies, the potential of an extract enriched with glycosylated flavonoids from the endemic Colombian high-mountain plant Baccharis antioquensis as a photoprotector and antioxidant was demonstrated. Therefore, in this work we sought to develop a dermocosmetic formulation with broad-spectrum photoprotection from the hydrolysates and purified polyphenols obtained from this species. Hence, the extraction of its polyphenols with different solvents was evaluated, followed by hydrolysis and purification, in addition to the characterization of its main compounds by HPLC-DAD and HPLC-MS, and evaluation of its photoprotective capacity through the measurement of the Sun Protection Factor (SPF), UVA Protection Factor (UVAPF), other Biological Effective Protection Factors (BEPFs), and its safety through the cytotoxicity. In the dry methanolic extract (DME) and purified methanolic extract (PME), flavonoids such as quercetin and kaempferol were found, which demonstrated antiradical capacity, as well as UVA-UVB photoprotection and prevention of harmful biological effects, such as elastosis, photoaging, immunosuppression, DNA damage, among others, which demonstrates the potential of the ingredients in this type of extract to be applied in photoprotection dermocosmetics.

Heterophase Polymorph of TiO2 (Anatase, Rutile, Brookite, TiO2 (B)) for Efficient Photocatalyst: Fabrication and Activity

TiO2 exists naturally in three crystalline forms: Anatase, rutile, brookite, and TiO2 (B). These polymorphs exhibit different properties and consequently different photocatalytic performances. This paper aims to clarify the differences between titanium dioxide polymorphs, and the differences in homophase, biphase, and triphase properties in various photocatalytic applications. However, homophase TiO2 has various disadvantages such as high recombination rates and low adsorption capacity. Meanwhile, TiO2 heterophase can effectively stimulate electron transfer from one phase to another causing superior photocatalytic performance. Various studies have reported the biphase of polymorph TiO2 such as anatase/rutile, anatase/brookite, rutile/brookite, and anatase/TiO2 (B). In addition, this paper also presents the triphase of the TiO2 polymorph. This review is mainly focused on information regarding the heterophase of the TiO2 polymorph, fabrication of heterophase synthesis, and its application as a photocatalyst.

Light-related activities of metal-based nanoparticles and their implications on dermatological treatment

Metal-based nanoparticles (MNPs) represent an emerging class of materials that have attracted enormous attention in many fields. By comparison with other biomaterials, MNPs own unique optical properties which make them a potential alternative to conventional therapeutic agents in medical applications. Especially, owing to the easy access to the skin, the use of MNPs based on their optical properties has gained importance for the treatment of a variety of skin diseases. This review provides an insight into the different optical properties of MNPs, including photoprotection, photocatalysis, and photothermal, and highlights their implications in treating skin disorders, with a special emphasis on their use in infection control. Finally, a perspective on the safety concern of MNPs for dermatological use is discussed and analyzed. The information gathered and presented in this review will help the readers have a comprehensive understanding of utilizing the photo-triggered activity of MNPs for the treatment of skin diseases.

Chemically-Engineered Porous Molecular Coatings as Reactive Oxygen Species Generators and Reservoirs for Long-Lasting Self-Cleaning Textiles

Wearable personal protective equipment that is decorated with photoactive self-cleaning materials capable of actively neutralizing biological pathogens is in high demand. Here, we developed a series of solution-processable, crystalline porous materials capable of addressing this challenge. Textiles coated with these materials exhibit a broad range of functionalities, including spontaneous ROS generation upon absorption of daylight, and long-term ROS storage in dark conditions. The ROS generation and storage abilities of these materials can be further improved through chemical engineering of the precursors without altering the three-dimensional assembled superstructures. In comparison with traditional TiO 2 or C 3 N 4 self-cleaning materials, the fluorinated molecular coating material HOF-101-F shows a 10- to 60-fold enhancement of ROS generation and 10- to 20- fold greater ROS storage ability. Our results pave the way for further developing self-cleaning textile coatings for the rapid deactivation of highly infectious pathogenic bacteria under both daylight and light-free conditions.

Functional composite hydrogels entrapping polydopamine hollow nanoparticles for highly efficient resistance of skin penetration and photoprotection

Living organisms tend to evolve various naturally photoprotective mechanisms to avoid photodamage. Among them, polydopamine (PDA) is an effective sunscreen, a mimic of melanin, which is the main functional component of the photoprotective system of human skin. However, the concerns of its dark color, skin penetration and photoprotective efficiency remain yet to be solved. Herein, we have constructed melanin-inspired nanocomposite hydrogels (CS-PDA_h-GP-HA) for photoprotection, in which PDA was prepared as hollow nanoparticles (PDA_h NPs) and entrapped in a physically cross-linked hydrogel (CS-GP-HA) formed by chitosan (CS) and hyaluronic acid (HA) using β-glycerophosphate (β-GP) as a modulator. The CS-PDA_h-GP-HA hydrogels exhibit a shear-thinning flow behavior with an elastic modulus of 300 Pa with the gel-sol transition temperature maintained at about 37 °C simply by adjusting the β-GP content in the hydrogels. The CS-PDA_h-GP-HA hydrogels also possess excellent resistance toward skin penetration. The photoprotective performances of CS-PDA_h-GP-HA hydrogels were evaluated by the determination of sun protection factor (SPF) and in vitro UVA protection efficacy (UVAPE) along with UV-Vis spectroscopy. Compared with the TiO₂ nanoparticles in CS-GP-HA hydrogel, the CS-PDA_h-GP-HA hydrogels show stronger shielding ability in both UVA and UVB regions. When protected by the CS-PDA_h-GP-HA hydrogels, the cell viability of NIH-3T3 fibroblasts increases to 96% while it was only 14% in the case of non-protecting group. These results suggest that the CS-PDA_h-GP-HA hydrogels could efficiently shield the UV irradiation and protect the skin from photodamage. This work introduces PDA-based nanocomposite hydrogels with safe, biocompatible and photoprotective properties, and provides a melanin-mimicking photoprotection system for the application in sunscreens.

Metal- and metal/oxide-based engineered nanoparticles and nanostructures: a review on the applications, nanotoxicological effects, and risk control strategies

The production and demand of nanoparticles in the manufacturing sector and personal care products, release a large number of engineered nanoparticles (ENPs) into the atmosphere, aquatic ecosystems, and terrestrial environments. The intentional or involuntary incorporation of ENPs into the environment is carried out through different processes. The ENPs are combined with other compounds and release into the atmosphere, settling on the ground due to the water cycle or other atmospheric phenomena. In the case of aquatic ecosystems, the ENPs undergo hetero-aggregation and sedimentation, reaching different living organisms and flora, as well as groundwater. Accordingly, the high mobility of ENPs in diverse ecosystems is strongly related to physical, chemical, and biological processes. Recent studies have been focused on the toxicological effects of a wide variety of ENPs using different validated biological models. This literature review emphasizes the study of toxicological effects related to using the most common ENPs, specifically metal and metal/oxides-based nanoparticles, addressing different synthesis methodologies, applications, and toxicological evaluations. The results suggest negative impacts on biological models, such as oxidative stress, metabolic and locomotive toxicity, DNA replication dysfunction, and bioaccumulation. Finally, it was consulted the protocols for the control of risks, following the assessment and management process, as well as the classification system for technological alternatives and risk management measures of ENPs, which are useful for the transfer of technology and nanoparticles commercialization.

On the IR spectroscopy and chemometric based rapid and non-destructive method for the investigation of sunscreen stains: Application in forensic science

Cosmetic products such as sunscreens may often be encountered in forensic investigations as traces left on tissue paper, apparels, drinkware, painted exterior, or various alternative surfaces. The pilot study aimed at efficiently using Infrared spectroscopy coupled with chemometrics to cater to unbiased, rapid, and non-destructive identification of sunscreens which will aid various forensic investigations soon. In the present research, a total of 109 sunscreen samples were analyzed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy. The physicochemical data from the FTIR instrument was then subjected to principal component analysis (PCA), which successfully distinguished most of the samples based on their spectral information. The trained model resulted in clear segregation of unknown sunscreen samples. This could provide an outstanding level of confidence during the conduction of 'questioned versus known' comparisons of similar sunscreens and will give the details of the manufacturer, thereby, helping in rounding off the suspects.

Optimization of sonochemical method of functionalizing Amino-Silane on superparamagnetic iron oxide nanoparticles using Central Composite Design

Optimization of sonochemical method of functionalizing a Silane coupling agent, Amino-Silane on Superparamagnetic Iron Oxide Nanoparticles (SPION) using Central Composite Design is reported. The Amino-Silane is grafted on the SPION in an iced bath environment using a Vibra-Cell 20 kHz ultrasonic irradiator with 13 mm diameter horn. Throughout the experiment amplitude of the ultrasonic device is maintained at 47%. The percentage atomic compositions of various APTES elements which bind to the SPION due to the ultrasonic irradiation were determined using X-ray photoelectron spectrometer (XPS). The influence of ultrasonic irradiation time and amount of APTES required for facile, rapid and effective functionalization of Organo-metallic compound on SPION are optimized. The optimized sonication time and amount of APTES are 8.49 min and 3.40 ml, respectively. The predicted results were validated with experimental data. Using the optimized values APTES were functionalized on the SPION experimentally and the results were compared. The experimental results validate the predicted data. Results show that very minimum sonication time is required for effective grafting of APTES on SPION.

Biochemical and histopathological impacts of rutile and anatase (TiO2 forms) in Mytilus galloprovincialis

Titanium dioxide (TiO₂) particles have been widely used in various industrial applications and consumer products. Due to their large production and use, they will eventually enter into aquatic environments. Once in the aquatic environment TiO₂ particles may interact with the organisms and induce toxic effects. Since the most common crystallographic forms of TiO₂ are rutile and anatase, the present study evaluated the effect of these two forms of TiO₂ particles in Mytilus galloprovincialis. For this, mussels were exposed to different concentrations of rutile and anatase particles (0, 5, 50, 100 µg/L) for twenty-eight days. Ti concentrations, histopathological alterations and biochemical effects were evaluated. Similar Ti concentrations were found in mussels exposed to rutile and anatase, with the highest values in mussels exposed to the highest exposure concentration. Histopathological results demonstrated that both forms of TiO₂ induced alterations on gills and digestive glands along the increasing exposure gradient. Biochemical markers showed that mussels exposed to rutile maintained their metabolic capacity (assessed by the activity of the Electron Transport System, ETS), while anatase increased the metabolism of mussels. Mussels exposed to rutile increased their detoxifying defences which, due to the low tested concentrations, were sufficient to avoid cellular damage. On the other hand, mussels exposed to anatase suffered cellular damages despite the increase of the antioxidant defences which may be related to the high ETS activity. Both rutile and anatase particles were toxic to M. galloprovincialis, being the highest oxidative stress exerted by the crystalline form anatase.

Biocompatible Ag/Fe-Enhanced TiO2 Nanoparticles as an Effective Compound in Sunscreens

In this work, valuable biocompatible Ag/Fe-enhanced TiO2 nanoparticles are comparatively prepared by a conventional wet chemistry method (sol-gel) and a rapid, efficient, hybrid unconventional method (microwave-assisted hydrothermal synthesis). In order to establish their application as effective compounds in sunscreens, the obtained powders were first structurally and morphologically characterized, analyses from which their nanodimensional character, crystalline structure and thermal behavior were highlighted. The evaluation of sunscreen effectiveness is based on the determination of the sun protection factor (SPF). It was observed that silver enhancing increases the SPF significantly, especially when compared to the pristine samples. The obtained Ag/Fe-enhanced TiO2 powders were also evaluated from the point of view of their biocompatibility on amniotic fluid stem cells, and the results indicated an enhance of cell proliferation when exposed to the synthesized nanostructures.

Enhancement of UV absorbance and mechanical properties of chitosan films by the incorporation of solvolytically fractionated lignins

In this work, an effective sequential organic solvent extraction of kraft and organosolv lignins was carried out to separate lignin into more homogeneous fractions with specific properties. The selected solvents were ethyl acetate, ethanol, methanol, and acetone in that order. Fractions were analysed in terms of their yield, molecular weight, S/G ratio, and phenolic hydroxyl groups content. The incorporation of lignin fractions into the chitosan was aimed to increase the UV absorbance and the mechanical resistance of the chitosan films, which would provide good properties for applications in the packaging field. Films were analysed in terms of UV-vis absorption spectra, tensile strength, as well as colour changes. Results showed a significant increase in the absorbance of UV-A and UV-B with the addition of lignin fractions, mechanical properties showed an increase in the ultimate tensile strength in case of kraft fractions, while organosolv fractions do not affect tensile strength significantly.

A Versatile Sunscreen with Minimal ROS Damage and Low Permeability

Organic and inorganic ultraviolet (UV) filters possess themselves advantages, while they suffer from different limitations including photostability, penetration, and cytotoxicity. Integrating organic and inorganic UV filters in a single unit holds great potential for enhanced UV protection. Herein, the dendritic silicon dioxide microspheres (DSMs) are encapsulated with Bi₂Ti₂O₇ nanocomposites (BTO-DSMs), an inorganic filter, and decorated with organic filters including sinapoyl malate (SM) and baicalin (BS/BTO-DSM) to enhance UV protection while significantly reducing ROS and skin permeability under UV exposure. The inorganic BTO-DSM component presents an expanded UV shield range and suppressed photocatalytic properties while preventing the organic filter SM direct contact with the epidermis and penetration behaviors. The baicalin efficiently scavenges the generated ROS from SM and reduces the transmittance of blue light. Notably, the results show that the proposed combined system significantly broadens the UV absorption region. Thus, the BS/BTO-DSM presents advanced in vitro anti-UV performance and in vivo UV protection against keratinocyte apoptosis and epidermal hyperplasia without long-term toxicity. The excellent anti-UV properties coupling with the suppressed photocatalytic capability and minimal epidermal penetration of BS/BTO-DSM make it promising for skin protection.

Synthesis of cosmetic grade TiO2-SiO2 core-shell powder from mechanically milled TiO2 nanopowder for commercial mass production

TiO₂ nanoparticles as an active sunscreen ingredient generate reactive oxygen species (ROS) upon UVA irradiation which is cytotoxic, genotoxic and potential to damage the DNA. The health concern and potential risks from TiO₂ can be mitigated by shielding the particles through the suitable coating. Considering the advantages of SiO₂, SiO₂ coated TiO₂ nanoparticles can be a potential material which can replace TiO₂ for thickening, whitening, lubricating, and sunscreen ingredient in cosmetics. This article reports the synthesis of cosmetic grade TiO₂-SiO₂ core-shell nanopowder from mechanically milled TiO₂ nanopowder for commercial mass production. From commercial TiO₂ nanopowder was fabricated through size reduction by nanoset milling. Followed by the fabricated TiO₂ nanopowder coated with SiO₂ through sol-gel technique. A suitable optimum condition was explored for cosmetic grade TiO₂-SiO₂ core-shell nanopowder. Various physical properties and optical properties were analyzed. Synthesized of cosmetic grade TiO₂-SiO₂ core-shell nanopowder found to be at 100 nm size, with a homogeneous SiO₂ coating having UVA protection factor 39 and sun protection factor (SPF) is 42. From the size, safety, and SPF perspective it can be an excellent cosmetic grade powder and from process simplicity perspective it can be commercially viable.