Biodegradable bioadhesive nanoparticle incorporation of broad-spectrum organic sunscreen agents

Environmental implications and nanotechnological advances in octocrylene-enriched sunscreen formulations: A comprehensive review

Ultraviolet (UV) radiation is a major contributor to skin aging, cancer, and other detrimental health effects. Sunscreens containing FDA-approved UV filters, like avobenzone, offer protection but suffer from photodegradation and potential phototoxicity. Encapsulation, antioxidants, and photostabilizers are strategies employed to combat these drawbacks. Octocrylene, an organic UV filter, utilizes nanotechnology to enhance sun protection factor (SPF). This review examines recent literature on octocrylene-enriched sunscreens, exploring the interplay between environmental impact, nanotechnological advancements, and clinical trial insights. A critical focus is placed on the environmental consequences of sunscreen use, particularly the potential hazards UV filters pose to marine ecosystems. Research in the Mediterranean Sea suggests bacterial sensitivity to these filters, raising concerns about their integration into the food chain. This review aims to guide researchers in developing effective strategies for photostabilization of UV filters. By combining encapsulation, photostabilizers, and antioxidants, researchers can potentially reduce phototoxic effects and contribute to developing more environmentally friendly sunscreens.

Exploring the potential of the nano-based sunscreens and antioxidants for preventing and treating skin photoaging

Excessive exposure to sunlight, especially UV irradiation, causes skin photodamage. Sunscreens, such as TiO2 and ZnO, can potentially prevent UV via scattering, reflection, and absorption. Topical antioxidants are another means of skin photoprotection. Developing nanoparticles for sunscreens and antioxidants is recommended for photoaging prevention and treatment as it can improve uncomfortable skin appearance, stability, penetration, and safety. This study reviewed the effects of nano-sized sunscreens and antioxidants on skin photoprevention by examining published studies and articles from PubMed, Scopus, and Google Scholar, which explore the topics of skin photoaging, skin senescence, UV radiation, keratinocyte, dermal fibroblast, sunscreen, antioxidant, and nanoparticle. The researchers of this study also summarized the nano-based UV filters and therapeutics for mitigating skin photoaging. The skin photodamage mechanisms are presented, followed by the introduction of current skin photoaging treatment. The different nanoparticle types used for topical delivery were also explored in this study. This is followed by the mechanisms of how nanoparticles improve the UV filters and antioxidant performance. Lastly, recent investigations were reviewed on nanoparticulate sunscreens and antioxidants in skin photoaging management. Sunscreens and antioxidants for topical application have different concepts. Topical antioxidants are ideal for permeating into the skin to exhibit free radical scavenging activity, while UV filters are prescribed to remain on the skin surface without absorption to exert the UV-blocking effect without causing toxicity. The nanoparticle design strategy for meeting the different needs of sunscreens and antioxidants is also explored in this study. Although the benefits of using nanoparticles for alleviating photodamage are well-established, more animal-based and clinical studies are necessary.

Nanoparticles as a Therapeutic Delivery System for Skin Cancer Prevention and Treatment

The use of nanoparticles (NPs) as a therapeutic delivery system has expanded markedly over the past decade, particularly regarding applications targeting the skin. The delivery of NP-based therapeutics to the skin requires special consideration owing to its role as both a physical and immunologic barrier, and specific technologies must not only take into consideration the target but also the pathway of delivery. The unique challenge this poses has been met with the development of a wide panel of NP-based technologies meant to precisely address these considerations. In this review article, we describe the application of NP-based technologies for drug delivery targeting the skin, summarize the types of NPs, and discuss the current landscape of NPs for skin cancer prevention and skin cancer treatment as well as future directions within these applications.

Anti-seed PNAs targeting multiple oncomiRs for brain tumor therapy

Glioblastoma (GBM) is one of the most lethal malignancies with poor survival and high recurrence rates. Here, we aimed to simultaneously target oncomiRs 10b and 21, reported to drive GBM progression and invasiveness. We designed short (8-mer) γ-modified peptide nucleic acids (sγPNAs), targeting the seed region of oncomiRs 10b and 21. We entrapped these anti-miR sγPNAs in nanoparticles (NPs) formed from a block copolymer of poly(lactic acid) and hyperbranched polyglycerol (PLA-HPG). The surface of the NPs was functionalized with aldehydes to produce bioadhesive NPs (BNPs) with superior transfection efficiency and tropism for tumor cells. When combined with temozolomide, sγPNA BNPs administered via convection-enhanced delivery (CED) markedly increased the survival (>120 days) of two orthotopic (intracranial) mouse models of GBM. Hence, we established that BNPs loaded with anti-seed sγPNAs targeting multiple oncomiRs are a promising approach to improve the treatment of GBM, with a potential to personalize treatment based on tumor-specific oncomiRs.

Chitosan-coated mesoporous silica particles as a plastic-free platform for photochemical suppression and stabilization of organic ultraviolet filters

Photochemical instability and reactivity of organic ultraviolet (UV) filters not only degrade the performance of sunscreen formulations but also generate toxic photodegradation products and reactive oxygen species (ROS). Although the encapsulation of organic UV filters into synthetic polymer particles has been widely investigated, synthetic plastics were recently banned for personal care and cosmetic products due to marine and coastal pollution issues. Here we present a plastic-free, photochemically stable and inactive UV filter platform based on chitosan-coated mesoporous silica microparticles, denoted 'mSOCPs', incorporating octyl methoxycinnamate (OMC) as a sunscreen agent. Sunlight induced the degradation of ∼80% free OMC in artificial sweat in 1 h at room temperature, while only 20% of OMC degraded for 3 h when encapsulated within mSOCPs. Moreover, mSOCPs efficiently suppressed the photochemical generation of ROS by about 99% through the combined effects of the mesoporous silica structure and chitosan coating. Accordingly, mSOCPs substantially increased the cell viability of fibroblasts exposed to UV irradiation. This work demonstrates that the biopolymer coatings of mesoporous inorganic particles can be a promising approach to the plastic-free encapsulation of organic UV filters for suppressing their photochemical reactivity and degradation.

Bioadhesive Nanoparticles for Local Drug Delivery

Local drug delivery is an effective strategy for achieving direct and instant therapeutic effects. Current clinical treatments have fallen short and are limited by traditional technologies. Bioadhesive nanoparticles (NPs), however, may be a promising carrier for optimized local drug delivery, offering prolonged drug retention time and steadily maintained therapeutic concentrations. In addition, the possibility of clinical applications of this platform are abundant, as most polymers used for bioadhesion are both biodegradable and biocompatible. This review highlights the major advances in the investigations of polymer-based bioadhesive nanoparticles and their innumerable applications in local drug delivery.

Hyaluronic acid/tannic acid hydrogel sunscreen with excellent anti-UV, antioxidant, and cooling effects

Excessive exposure to UV radiation is one of the major factors that causes skin aging, erythema, burns, and skin cancer. Recently, the usage of sunscreens for skin protection has increased because the amount of UV radiation reaching the Earth's surface has increased owing to the destruction of the ozone layer that blocks UV radiation. Hydrogels with a three-dimensional network structure exhibit physical and chemical properties that are similar to those of the extracellular matrix in the human body, a high water content, flexibility, and biocompatibility. Therefore, they are applied in a wide range of fields, such as in cosmetics, medicines, and pharmaceuticals. However, conventional hydrogel-based sunscreens have drawbacks such as complicated process conditions, high cost, and low biocompatibility. In this study, a novel hydrogel-type sunscreen with excellent UV protection and cooling effects was prepared by a very simple process using two natural materials, hyaluronic acid (HA) and tannic acid (TA). The HA/TA hydrogels exhibited broad-spectrum UV protection in the UVA and UVB regions (280-360 nm). In addition, they showed excellent adhesion to the skin surface, antioxidative activity, cooling effect, and high moisture content, demonstrating great application potential as a hydrogel-type sunscreen.

Yeast cell microcarriers for delivery of a model bioactive compound in skin

This study aimed at developing a cell-based encapsulation carrier for topical delivery of bioactives to the skin. The overall objectives were to evaluate affinity of the yeast-cell based carrier to bind to the skin surface following topical application and to quantify controlled release of curcumin as a model bioactive in ex-vivo skin models using a combination of imaging, modeling and analytical measurements. Both porcine skin tissue and clinically obtained human skin biopsies were studied. The results demonstrated that upon incubation with the ex-vivo skin tissues, the cell carriers rapidly bound to the skin surface following topical delivery and provided sustained release of encapsulated curcumin. The microcarrier binding and penetration of curcumin in the dermal compartment also showed to increase with incubation time. The average flux of curcumin in human skin biopsies J_p was 0.89 ± 0.02 μg/cm²/h. These results illustrated the potential of a novel cell-based carrier for high affinity binding to skin surface, efficient encapsulation of a model bioactive and controlled release from the cell carrier to the skin with enhanced permeation to the dermis section. Overall, this study demonstrated a new class of cost-effective carriers for improving delivery of bioactives to the skin and potentially other epithelial tissues.

The emerging role of nanotechnology in skincare

The role of cosmetic products is rapidly evolving in our society, with their use increasingly seen as an essential contribution to personal wellness. This suggests the necessity of a detailed elucidation of the use of nanoparticles (NPs) in cosmetics. The aim of the present work is to offer a critical and comprehensive review discussing the impact of exploiting nanomaterials in advanced cosmetic formulations, emphasizing the beneficial effects of their extensive use in next-generation products despite a persisting prejudice around the application of nanotechnology in cosmetics. The discussion here includes an interpretation of the data underlying generic information reported on the product labels of formulations already available in the marketplace, information that often lacks details identifying specific components of the product, especially when nanomaterials are employed. The emphasis of this review is mainly focused on skincare because it is believed to be the cosmetics market sector in which the impact of nanotechnology is being seen most significantly. To date, nanotechnology has been demonstrated to improve the performance of cosmetics in a number of different ways: 1) increasing both the entrapment efficiency and dermal penetration of the active ingredient, 2) controlling drug release, 3) enhancing physical stability, 4) improving moisturizing power, and 5) providing better UV protection. Specific attention is paid to the effect of nanoparticles contained in semisolid formulations on skin penetration issues. In light of the emerging concerns about nanoparticle toxicity, an entire section has been devoted to listing detailed examples of nanocosmetic products for which safety has been investigated.

Nonsurgical treatment of skin cancer with local delivery of bioadhesive nanoparticles

Keratinocyte-derived carcinomas, including squamous cell carcinoma (SCC), comprise the most common malignancies. Surgical excision is the therapeutic standard but is not always clinically feasible, and currently available alternatives are limited to superficial tumors. To address the need for a nonsurgical treatment for nodular skin cancers like SCC, we developed a bioadhesive nanoparticle (BNP) drug delivery system composed of biodegradable polymer, poly(lactic acid)-hyperbranched polyglycerol (PLA-HPG), encapsulating camptothecin (CPT). Nanoparticles (NPs) of PLA-HPG are nonadhesive NPs (NNPs), which are stealthy in their native state, but we have previously shown that conversion of the vicinal diols of HPG to aldehydes conferred NPs the ability to form strong covalent bonds with amine-rich surfaces. Herein, we show that these BNPs have significantly enhanced binding to SCC tumor cell surfaces and matrix proteins, thereby significantly enhancing the therapeutic efficacy of intratumoral drug delivery. Tumor injection of BNP-CPT resulted in tumor retention of CPT at ∼50% at 10 d postinjection, while CPT was undetectable in NNP-CPT or free (intralipid) CPT-injected tumors at that time. BNP-CPT also significantly reduced tumor burden, with a portion (∼20%) of BNP-CPT-treated established tumors showing histologic cure. Larger, more fully established PDV SCC tumors treated with a combination of BNP-CPT and immunostimulating CpG oligodeoxynucleotides exhibited enhanced survival relative to controls, revealing the potential for BNP delivery to be used along with local tumor immunotherapy. Taken together, these results indicate that percutaneous delivery of a chemotherapeutic agent via BNPs, with or without adjuvant immunostimulation, represents a viable, nonsurgical alternative for treating cutaneous malignancy.

UVA-Triggered Drug Release and Photo-Protection of Skin

Light has attracted special attention as a stimulus for triggered drug delivery systems (DDS) due to its intrinsic features of being spatially and temporally tunable. Ultraviolet A (UVA) radiation has recently been used as a source of external light stimuli to control the release of drugs using a "switch on- switch off" procedure. This review discusses the promising potential of UVA radiation as the light source of choice for photo-controlled drug release from a range of photo-responsive and photolabile nanostructures via photo-isomerization, photo-cleavage, photo-crosslinking, and photo-induced rearrangement. In addition to its clinical use, we will also provide here an overview of the recent UVA-responsive drug release approaches that are developed for phototherapy and skin photoprotection.

Unplanned absorption of sunscreen ingredients: Impact of formulation and evaluation methods

Permeation of sunscreens agents reduces its effectiveness and safety, leading to systemic circulation and causing unknown adverse effects. In order to maintain the sunscreen efficacy and safety, the filters must stay on the skin surface, with minimum penetration through dermis. Even facing the possibility of filters permeation, the use of sunscreen is important to avoid skin damage as erythema, free-radicals formation, skin ageing and skin cancer, caused by ultraviolet radiation. Aiming potential side effects caused by topical absorption of sunscreens, studies are carried to improve formulation characteristics and stability, reduce skin permeation and evaluate sun protections factor (SPF). Current assays to detect the permeation of sunscreens involve in vivo or in vitro studies, to simulate physiological conditions of use. The aim of this review is to revisit sunscreen skin permeation data over the last decade and the factors that can enhance skin permeation or improve the sunscreen efficacy.

Nanoparticles for topical drug delivery: Potential for skin cancer treatment

Nanoparticles offer new opportunities for the treatment of skin diseases. The barrier function of the skin poses a significant challenge for nanoparticles to permeate into the tissue, although the barrier is partially compromised in case of injury or inflammation, as in the case of skin cancer. This may facilitate the penetration of nanoparticles. Extensive research has gone into developing nanoparticles for topical delivery; however, relatively little progress has been made in translating them to the clinic for treating skin cancers. We summarize the types of skin cancers and practices in current clinical management. The review provides a comprehensive outlook of the various nanoparticle technologies tested for topical therapy of skin cancers and summarizes the obstacles that impede its progress from the bench-to-bedside. The review also aims to provide an understanding of the pathways that govern nanoparticle penetration into the skin and a critical analysis of the approaches used to study nanoparticle interactions within the tissue.

Development, Cytotoxicity and Eye Irritation Profile of a New Sunscreen Formulation Based on Benzophenone-3-poly(ε-caprolactone) Nanocapsules

The objective of this work was to characterize the toxicological profile of a newly developed sunscreen formulation based on polymeric nanocapsules (NCs) loading benzophenone-3 (BZP3). NCs composed of poly(ε-caprolactone) carrot oil and Pluronic^® F68 were produced by emulsification-diffusion method. Their mean particle size (Z-Ave) ranged from 280 to 420 nm, polydispersity index (PDI) was below 0.37, while zeta potential (ZP) reached about |+11 mV|. No cytotoxic effects were observed in L929 fibroblast cell line for the blank (i.e., non-loaded) NCs and BZP3-loaded NCs (BZP3-NCs). The semi-solid sunscreen formulation was stable over time (centrifugation testing) and exhibited non-Newtonian pseudoplastic behavior, which is typical of products for topical application onto the skin. The sun protection factor (SPF) value reached 8.84, when incorporating BZP3-NCs (SPF of 8.64) into the semi-solid formulation. A synergistic effect was also observed when combining the formulation ingredients of nanocapsules, i.e., SPF of carrot oil was 6.82, blank NCs was 6.84, and BZP3-loaded NCs was 8.64. From the hen’s egg-chorioallantoic membrane test (HET-CAM) test, the non-irritation profile of the developed formulations could also be confirmed. The obtained results show a promising use of poly(ε-caprolactone) nanocapsules to be loaded with lipophilic sunscreens as benzophenone-3.

Nanocarriers and Microcarriers for Enhancing the UV Protection of Sunscreens: An Overview

This review addresses a major question of importance to pharmaceutical scientists: how can novel drug delivery systems play a role in maximizing the UV protection of sunscreens? Because more and more people are being diagnosed with skin cancer each year than all other cancers combined, adequate sun protective measures are pivotal. In this context, the present review is to give an up-to-date overview on the different nanocarrier systems that have been explored so far for encapsulating different types of UV filters present on the market. The aim of these carrier systems is to prevent skin penetration and to enhance the photoprotective potential of sunscreen actives. For each supramolecular system, a brief description along with the studies, achievements, and pitfalls, on the type of UV actives inside them, ranging from classical UV filters to new generation of UV actives is given. A brief overview of UV filters encapsulated in microcarriers is also discussed.

Focus on Fundamentals: Achieving Effective Nanoparticle Targeting

Successful molecular targeting of nanoparticle drug carriers can enhance therapeutic specificity and reduce systemic toxicity. Typically, ligands specific for cognate receptors expressed on the intended target cell type are conjugated to the nanoparticle surface. This approach, often called active targeting, seems to imply that the conjugated ligand imbues the nanoparticle with homing capacity. However, ligand-receptor interactions are mediated by short-range forces and cannot produce magnetic-like attraction over larger distances. Successful targeting actually involves two key characteristics: contact of the nanoparticle with the intended target cell and subsequent ligand-mediated retention at the site. Here we propose a conceptual framework, based on recent literature combined with basic principles of molecular interactions, to guide rational design of nanoparticle targeting strategies.