Nanoengineered silica: Properties, applications and toxicity

Biocompatibility Analysis of Bio-Based and Synthetic Silica Nanoparticles during Early Zebrafish Development

During the twenty-first century, engineered nanomaterials (ENMs) have attracted rising interest, globally revolutionizing all industrial sectors. The expanding world population and the implementation of new global policies are increasingly pushing society toward a bioeconomy, focused on fostering the adoption of bio-based nanomaterials that are functional, cost-effective, and potentially secure to be implied in different areas, the medical field included. This research was focused on silica nanoparticles (SiO2-NPs) of bio-based and synthetic origin. SiO2-NPs are composed of silicon dioxide, the most abundant compound on Earth. Due to their characteristics and biocompatibility, they are widely used in many applications, including the food industry, synthetic processes, medical diagnosis, and drug delivery. Using zebrafish embryos as in vivo models, we evaluated the effects of amorphous silica bio-based NPs from rice husk (SiO2-RHSK NPs) compared to commercial hydrophilic fumed silica NPs (SiO2-Aerosil200). We evaluated the outcomes of embryo exposure to both nanoparticles (NPs) at the histochemical and molecular levels to assess their safety profile, including developmental toxicity, neurotoxicity, and pro-inflammatory potential. The results showed differences between the two silica NPs, highlighting that bio-based SiO2-RHSK NPs do not significantly affect neutrophils, macrophages, or other innate immune system cells.

Recent advances of nanoparticles on bone tissue engineering and bone cells

With the development of biotechnology, biomaterials have been rapidly developed and shown great potential in bone regeneration therapy and bone tissue engineering. Nanoparticles have attracted the attention of researches and have applied in various fields especially in the biomedical field as the special physicochemical properties. Nanoparticles were found to regulate bone remodeling depending on their size, shape, composition, and charge. Therefore, in-depth research was necessary to provide the basic support to select the most suitable nanoparticles for bone relate diseases treatment. This article reviews the current development of nanoparticles in bone tissue engineering, focusing on drug delivery, gene delivery, and cell labeling. In addition, the research progress on the interaction of nanoparticles with bone cells, focusing on osteoblasts, osteoclasts, and bone marrow mesenchymal stem cells, and the underlying mechanism were also reviewed. Finally, the current challenges and future research directions are discussed. Thus, detailed study of nanoparticles may reveal new therapeutic strategies to improve the effectiveness of bone regeneration therapy or other bone diseases.

Ferroptosis contributing to cardiomyocyte injury induced by silica nanoparticles via miR-125b-2-3p/HO-1 signaling

BACKGROUND

Amorphous silica nanoparticles (SiNPs) have been gradually proven to threaten cardiac health, but pathogenesis has not been fully elucidated. Ferroptosis is a newly defined form of programmed cell death that is implicated in myocardial diseases. Nevertheless, its role in the adverse cardiac effects of SiNPs has not been described.

RESULTS

We first reported the induction of cardiomyocyte ferroptosis by SiNPs in both in vivo and in vitro. The sub-chronic exposure to SiNPs through intratracheal instillation aroused myocardial injury, characterized by significant inflammatory infiltration and collagen hyperplasia, accompanied by elevated CK-MB and cTnT activities in serum. Meanwhile, the activation of myocardial ferroptosis by SiNPs was certified by the extensive iron overload, declined FTH1 and FTL, and lipid peroxidation. The correlation analysis among detected indexes hinted ferroptosis was responsible for the SiNPs-aroused myocardial injury. Further, in vitro tests, SiNPs triggered iron overload and lipid peroxidation in cardiomyocytes. Concomitantly, altered expressions of TfR, DMT1, FTH1, and FTL indicated dysregulated iron metabolism of cardiomyocytes upon SiNP stimuli. Also, shrinking mitochondria with ridge fracture and ruptured outer membrane were noticed. To note, the ferroptosis inhibitor Ferrostatin-1 could effectively alleviate SiNPs-induced iron overload, lipid peroxidation, and myocardial cytotoxicity. More importantly, the mechanistic investigations revealed miR-125b-2-3p-targeted HO-1 as a key player in the induction of ferroptosis by SiNPs, probably through regulating the intracellular iron metabolism to mediate iron overload and ensuing lipid peroxidation.

CONCLUSIONS

Our findings firstly underscored the fact that ferroptosis mediated by miR-125b-2-3p/HO-1 signaling was a contributor to SiNPs-induced myocardial injury, which could be of importance to elucidate the toxicity and provide new insights into the future safety applications of SiNPs-related nano products.

Mesoporous silica nanoparticles: A versatile platform for encapsulation and delivery of essential oils for food applications

Essential oils (EOs) are biologically active and volatile substances that have found widespread applications in the food, cosmetics, and pharmaceutical industries. However, there are some challenges to their commercial utilization due to their high volatility, susceptibility to degradation, and hydrophobicity. In their free form, EOs can quickly evaporate, as well as undergo degradation reactions like oxidation, isomerization, dehydrogenation, or polymerization when exposed to light, heat, or air. Encapsulating EOs within mesoporous silica nanoparticles (MSNPs) could overcome these limitations and thereby broaden their usage. MSNPs may endow protection and slow-release properties to EOs, thereby extending their stability, enhancing their efficacy, and improving their dispersion in aqueous environments. This review explores and compares the design and development of different MSNP-based nanoplatforms to encapsulate, protect, and release EOs. Initially, a brief overview of the various types of available MSNPs, their properties, and their synthesis methods is given to better understand their roles as carriers for EOs. Several encapsulation technologies are then examined, including solvent-based and solvent-free methods. The suitability of each technology for EO encapsulation, as well as its impact on their stability and release, is discussed in detail. Opportunities and challenges for using EO-loaded MSNPs as preservatives, flavor enhancers, and antimicrobial agents in the food industry are then highlighted. Overall, this review aims to bridge a knowledge gap by providing a thorough understanding of EO encapsulation within MSNPs, which should facilitate the application of this technology in the food industry.

Preparation and characterization of polyvinyl alcohol (PVA)-glycerol composite films incorporating nanosilica from municipal solid waste incinerator bottom ash

This study investigates the fabrication of a composite film composed of polyvinyl alcohol (PVA) and glycerol, incorporating nanosilica derived from municipal solid waste incinerator bottom ash (BA). The nanosilica is blended with a PVA film-forming solution containing glycerol as a plasticizer. The composite films are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Additionally, thermogravimetric analysis (TGA) is conducted to evaluate the thermal properties, while the mechanical properties are assessed in terms of tensile strength (TS) and elongation at break (EAB). The results indicate that the presence of silica nanoparticles reduces transparency and increases film thickness in the presence of glycerol. Notably, the film containing 1% silica demonstrates a significant enhancement in tensile strength, exhibiting a 50% increase compared to the film without silica. However, higher silica loadings lead to a deterioration in mechanical properties due to silica agglomeration within the polymer matrix. As expected, the presence of silica in the films slightly elevates the degradation temperature.

Advances in the study of silica nanoparticles in lung diseases

Silicon dioxide nanoparticles (SiNPs) are one of the major forms of silicon dioxide and are composed of the most-abundant compounds on earth. Based on their excellent properties, SiNPs are widely used in food production, synthetic processes, medical diagnostics, drug delivery, and other fields. The mass production and wide application of SiNPs increases the risk of human exposure to SiNPs. In the workplace and environment, SiNPs mainly enter the human body through the respiratory tract and reach the lungs; therefore, the lungs are the most important and most toxicologically affected target organ of SiNPs. An increasing number of studies have shown that SiNP exposure can cause severe lung toxicity. However, studies on the toxicity of SiNPs in ex vivo and in vivo settings are still in the exploratory phase. The molecular mechanisms underlying the lung toxicity of SiNPs are varied and not yet fully understood. As a result, this review summarizes the possible mechanisms of SiNP-induced lung toxicity, such as oxidative stress, endoplasmic reticulum stress, mitochondrial damage, and cell death. Moreover, this study provides a summary of the progression of diseases caused by SiNPs, thereby establishing a theoretical basis for future studies on the mechanisms of SiNP-induced lung toxicity.

Silica nanoparticles induce ferroptosis of HUVECs by triggering NCOA4-mediated ferritinophagy

Silica nanoparticles (SiNPs) have been widely used in electronics, chemistry, and biomedicine. Human exposure to SiNPs and possible health effects have attracted much attention. The potential cardiovascular toxicity of SiNPs and their related mechanisms are still unclear. Therefore, in this study, we investigated the toxic effects of SiNPs on human umbilical vein endothelial cells (HUVECs). We found that SiNPs could induce HUVECs ferroptosis. The results showed that the level of intracellular divalent iron and lipid peroxidation increased, and mitochondrial cristae decreased. In addition, the pretreatment of the iron chelator deferoxamine mesylate (DFO) could alleviate the ferroptosis of cells. Interestingly, pretreatment of 3-methyladenine (3-MA), an autophagy/PI3K inhibitor could partially inhibit autophagy and reduce ferroptosis, which indicated that autophagy played an important role in cell ferroptosis. Additionally, after knocking down nuclear receptor coactivator 4 (NCOA4), Ferritin Heavy Chain 1 (FTH1) expression was up-regulated, and the levels of divalent iron and lipid peroxidation decreased, which suggested that NCOA4 mediated the ferroptosis of HUVECs induced by SiNPs. In conclusion, this study shows that SiNPs can induce cardiovascular toxicity in which there is ferroptosis. NCOA4-mediated ferritinophagy and resultant ferroptosis by SiNPs may play an important role. This study provides a new theoretical strategy for the treatment and prevention of cardiovascular diseases in the future.

Prospects and hazards of silica nanoparticles: Biological impacts and implicated mechanisms

With the thrive of nanotechnology, silica nanoparticles (SiNPs) have been extensively adopted in the agriculture, food, cosmetic, and even biomedical industries. Due to the mass production and use, SiNPs inevitably entered the environment, resulting in ecological toxicity and even posing a threat to human health. Although considerable investigations have been conducted to assess the toxicity of SiNPs, the correlation between SiNPs exposure and consequent health risks remains ambiguous. Since the biological impacts of SiNPs can differ from their design and application, the toxicity assessment for SiNPs may be extremely difficult. This review discussed the application of SiNPs in different fields, especially their biomedical use, and documented their potential release pathways into the environment. Meanwhile, the current process of assessing SiNPs-related toxicity on various model organisms and cell lines was also detailed, thus estimating the health threats posed by SiNPs exposure. Finally, the potential toxic mechanisms of SiNPs were also elaborated based on results obtained from both in vivo and in vitro trials. This review generally summarizes the biological effects of SiNPs, which will build up a comprehensive perspective of the application and toxicity of SiNPs.

The role of cGAS-STING signaling in pulmonary fibrosis and its therapeutic potential

Pulmonary fibrosis is a progressive and ultimately fatal lung disease, exhibiting the excessive production of extracellular matrix and aberrant activation of fibroblast. While Pirfenidone and Nintedanib are FDA-approved drugs that can slow down the progression of pulmonary fibrosis, they are unable to reverse the disease. Therefore, there is an urgent demand to develop more efficient therapeutic approaches for pulmonary fibrosis. The intracellular DNA sensor called cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) plays a crucial role in detecting DNA and generating cGAMP, a second messenger. Subsequently, cGAMP triggers the activation of stimulator of interferon genes (STING), initiating a signaling cascade that leads to the stimulation of type I interferons and other signaling molecules involved in immune responses. Recent studies have highlighted the involvement of aberrant activation of cGAS-STING contributes to fibrotic lung diseases. This review aims to provide a comprehensive summary of the current knowledge regarding the role of cGAS-STING pathway in pulmonary fibrosis. Moreover, we discuss the potential therapeutic implications of targeting the cGAS-STING pathway, including the utilization of inhibitors of cGAS and STING.

Targeting STING-mediated pro-inflammatory and pro-fibrotic effects of alveolar macrophages and fibroblasts blunts silicosis caused by silica particles

Silica is utilized extensively in industrial and commercial applications as a chemical raw material, increasing its exposure and hazardous potential to populations, with silicosis serving as an important representative. Silicosis is characterized by persistent lung inflammation and fibrosis, for which the underlying pathogenesis of silicosis is unclear. Studies have shown that the stimulating interferon gene (STING) participates in various inflammatory and fibrotic lesions. Therefore, we speculated that STING might also play a key role in silicosis. Here we found that silica particles drove the double-stranded DNA (dsDNA) release to activate the STING signal pathway, contributing to alveolar macrophages (AMs) polarization by secreting diverse cytokines. Then, multiple cytokines could generate a micro-environment to exacerbate inflammation and promote the activation of lung fibroblasts, hastening fibrosis. Intriguingly, STING was also crucial for the fibrotic effects induced by lung fibroblasts. Loss of STING could effectively inhibit silica particles-induced pro-inflammatory and pro-fibrotic effects by regulating macrophages polarization and lung fibroblasts activation to alleviate silicosis. Collectively, our results have revealed a novel pathogenesis of silica particles-caused silicosis mediated by the STING signal pathway, indicating that STING may be regarded as a promising therapeutic target in the treatment of silicosis.

Amorphous silica nanoparticles cause abnormal cytokinesis and multinucleation through dysfunction of the centralspindlin complex and microfilaments

BACKGROUND

With the large-scale production and application of amorphous silica nanoparticles (aSiNPs), its adverse health effects are more worthy of our attention. Our previous research has demonstrated for the first time that aSiNPs induced cytokinesis failure, which resulted in abnormally high incidences of multinucleation in vitro, but the underlying mechanisms remain unclear. Therefore, the purpose of this study was firstly to explore whether aSiNPs induced multinucleation in vivo, and secondly to investigate the underlying mechanism of how aSiNPs caused abnormal cytokinesis and multinucleation.

METHODS

Male ICR mice with intratracheal instillation of aSiNPs were used as an experimental model in vivo. Human hepatic cell line (L-02) was introduced for further mechanism study in vitro.

RESULTS

In vivo, histopathological results showed that the rate of multinucleation was significantly increased in the liver and lung tissue after aSiNPs treatment. In vitro, immunofluorescence results manifested that aSiNPs directly caused microfilaments aggregation. Following mechanism studies indicated that aSiNPs increased ROS levels. The accumulation of ROS further inhibited the PI3k 110β/Aurora B pathway, leading to a decrease in the expression of centralspindlin subunits MKLP1 and CYK4 as well as downstream cytokines regulation related proteins Ect2, Cep55, CHMP2A and RhoA. Meanwhile, the particles caused abnormal co-localization of the key mitotic regulatory kinase Aurora B and the centralspindlin complex by inhibiting the PI3k 110β/Aurora B pathway. PI3K activator IGF increased the phosphorylation level of Aurora B and improved the relative ratio of the centralspindlin cluster. And ROS inhibitors NAC reduced the ratio of multinucleation, alleviated the PI3k 110β/Aurora B pathway inhibition, and then increased the expression of MKLP1, CYK4 and cytokinesis-related proteins, whilst NAC restored the clustering of the centralspindlin.

CONCLUSION

This study demonstrated that aSiNPs led to multinucleation formation both in vivo and in vitro. ASiNPs exposure caused microfilaments aggregation and inhibited the PI3k 110β/Aurora B pathway through excessive ROS, which then hindered the centralspindlin cluster as well as restrained the expression of centralspindlin subunits and cytokinesis-related proteins, which ultimately resulted in cytokinesis failure and the formation of multinucleation.

Photoprotective and Anti-Aging Properties of the Apical Frond Extracts from the Mediterranean Seaweed Ericaria amentacea

There is a growing interest in using brown algal extracts thanks to the bioactive substances they produce for adaptation to the marine benthic environment. We evaluated the anti-aging and photoprotective properties of two types of extracts (50%-ethanol and DMSO) obtained from different portions, i.e., apices and thalli, of the brown seaweed, Ericaria amentacea. The apices of this alga, which grow and develop reproductive structures during summer when solar radiation is at its peak, were postulated to be rich in antioxidant compounds. We determined the chemical composition and pharmacological effects of their extracts and compared them to the thallus-derived extracts. All the extracts contained polyphenols, flavonoids and antioxidants and showed significant biological activities. The hydroalcoholic apices extracts demonstrated the highest pharmacological potential, likely due to the higher content of meroditerpene molecular species. They blocked toxicity in UV-exposed HaCaT keratinocytes and L929 fibroblasts and abated the oxidative stress and the production of pro-inflammatory cytokines, typically released after sunburns. Furthermore, the extracts showed anti-tyrosinase and anti-hydrolytic skin enzyme activity, counteracting the collagenase and hyaluronidase degrading activities and possibly slowing down the formation of uneven pigmentation and wrinkles in aging skin. In conclusion, the E. amentacea apices derivatives constitute ideal components for counteracting sunburn symptoms and for cosmetic anti-aging lotions.

Nanoparticle protein corona: from structure and function to therapeutic targeting

Nanoparticle (NP)-based therapeutics have ushered in a new era in translational medicine. However, despite the clinical success of NP technology, it is not well-understood how NPs fundamentally change in biological environments. When introduced into physiological fluids, NPs are coated by proteins, forming a protein corona (PC). The PC has the potential to endow NPs with a new identity and alter their bioactivity, stability, and destination. Additionally, the conformation of proteins is sensitive to their physical and chemical surroundings. Therefore, biological factors and protein-NP-interactions can induce changes in the conformation and orientation of proteins in vivo. Since the function of a protein is closely connected to its folded structure, slight differences in the surrounding environment as well as the surface characteristics of the NP materials may cause proteins to lose or gain a function. As a result, this can alter the downstream functionality of the NPs. This review introduces the main biological factors affecting the conformation of proteins associated with the PC. Then, four types of NPs with extensive utility in biomedical applications are described in greater detail, focusing on the conformation and orientation of adsorbed proteins. This is followed by a discussion on the instances in which the conformation of adsorbed proteins can be leveraged for therapeutic purposes, such as controlling protein conformation in assembled matrices in tissue, as well as controlling the PC conformation for modulating immune responses. The review concludes with a perspective on the remaining challenges and unexplored areas at the interface of PC and NP research.

A review of the extraction methods and advanced applications of lignin-silica hybrids derived from natural sources

The global trend of increasing energy demand along the large volume of wastewater generated annually from the paper pulping and cellulose production industries are considered as serious dilemma that may need to be solved within these current decades. Within this discipline, lignin, silica or lignin-silica hybrids attained from biomass material have been considered as prospective candidates for the synthesis of advanced materials. In this study, the roles and linking mechanism between lignin and silica in plants were studied and evaluated. The effects of the extraction method on the quality of the obtained material were summarized to show that depending on the biomass feedstocks, different retrieval processes should be considered. The combination of alkaline treatment and acidic pH adjustment is proposed as an effective method to recover lignin-silica with high applicability for various types of raw materials. From considerations of the advanced applications of lignin and silica materials in environmental remediation, electronic devices and rubber fillers future valorizations hold potential in conductive materials and electrochemistry. Along with further studies, this research could not only contribute to the development of zero-waste manufacturing processes but also propose a solution for the fully exploiting of by-products from agricultural production.

Brief History, Preparation Method, and Biological Application of Mesoporous Silica Molecular Sieves: A Narrative Review

It has been more than 30 years since the first ordered mesoporous silica molecular sieve (MCM-41) was reported, but the enthusiasm for exploiting mesoporous silica is still growing due to its superior properties, such as its controllable morphology, excellent hosting capability, easy functionalization, and good biocompatibility. In this narrative review, the brief history of the discovery of mesoporous silica and several important mesoporous silica families are summarized. The development of mesoporous silica microspheres with nanoscale dimensions, hollow mesoporous silica microspheres, and dendritic mesoporous silica nanospheres is also described. Meanwhile, common synthesis methods for traditional mesoporous silica, mesoporous silica microspheres, and hollow mesoporous silica microspheres are discussed. Then, we introduce the biological applications of mesoporous silica in fields such as drug delivery, bioimaging, and biosensing. We hope this review will help people to understand the history of the development of mesoporous silica molecular sieves and become familiar with their synthesis methods and applications in biology.

Silica Nanoparticles Trigger Chaperone HSPB8-Assisted Selective Autophagy via TFEB Activation in Hepatocytes

Silica nanoparticles (SiNPs) are one of the most common inorganic nanomaterials. Autophagy is the predominant biological response to nanoparticles and transcription factor EB (TFEB) is a master regulator of the autophagy-lysosome pathway. Previous studies show that SiNPs induce autophagosome accumulation, yet the precise underlying mechanisms remain uncertain. The present study investigates the role of TFEB during SiNP-induced autophagy. SiNP-induced TFEB nuclear translocation is verified using immunofluorescence and western blot assay. The regulation of TFEB is proved to be via EIF2AK3 pathway. A TFEB knockout (KO) cell line is constructed to validate the TFEB involvement in SiNP-induced autophagy. The transcriptomes of wild-type and TFEB KO cells are compared using RNA-sequencing to identify genes of the TFEB-mediated autophagy and lysosome pathways affected by SiNPs. Based on these data and the Human Autophagy Database, four candidate autophagic genes are identified, including HSPB8, ATG4D, CTSB and CTSD. Specifically, that the chaperone HSPB8 is upregulated through SiNP-mediated TFEB activation and forms a chaperone-assisted selective autophagy (CASA) complex with BAG3 and HSC70, triggering HSPB8-assisted selective autophagy, is found. Thus, this study characterizes a novel mechanism underlying SiNP-induced autophagy that helps pave the way for further research on the toxicity and risk assessment of SiNPs.

The Study of Nanosized Silicate-Substituted Hydroxyapatites Co-Doped with Sr2+ and Zn2+ Ions Related to Their Influence on Biological Activities

Nanosized silicate-substituted hydroxyapatites, characterized by the general formula Ca_9.8-x-nSr_nZn_x(PO₄)_6-y(SiO₄)_y(OH)₂ (where: n = 0.2 [mol%]; x = 0.5-3.5 [mol%]; y = 4-5 [mol%]), co-doped with Zn²⁺ and Sr²⁺ ions, were synthesized with the help of a microwave-assisted hydrothermal technique. The structural properties were determined using XRD (X-ray powder diffraction) and Fourier-transformed infrared spectroscopy (FT-IR). The morphology, size and shape of biomaterials were detected using scanning electron microscopy techniques (SEM). The reference strains of Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa were used to assess bacterial survivability and the impact on biofilm formation in the presence of nanosilicate-substituted strontium-hydroxyapatites. Safety evaluation was also performed using the standard cytotoxicity test (MTT) and hemolysis assay. Moreover, the mutagenic potential of the materials was assessed (Ames test). The obtained results suggest the dose-dependent antibacterial activity of nanomaterials, especially observed for samples doped with 3.5 mol% Zn²⁺ ions. Moreover, the modification with five SiO₄ groups enhanced the antibacterial effect; however, a rise in the toxicity was observed as well. No harmful activity was detected in the hemolysis assay as well as in the mutagenic assay (Ames test).

Grouping of orally ingested silica nanomaterials via use of an integrated approach to testing and assessment to streamline risk assessment

BACKGROUND

Nanomaterials can exist in different nanoforms (NFs). Their grouping may be supported by the formulation of hypotheses which can be interrogated via integrated approaches to testing and assessment (IATA). IATAs are decision trees that guide the user through tiered testing strategies (TTS) to collect the required evidence needed to accept or reject a grouping hypothesis. In the present paper, we investigated the applicability of IATAs for ingested NFs using a case study that includes different silicon dioxide, SiO₂ NFs. Two oral grouping hypotheses addressing local and systemic toxicity were identified relevant for the grouping of these NFs and verified through the application of oral IATAs. Following different Tier 1 and/or Tier 2 in vitro methods of the TTS (i.e., in vitro dissolution, barrier integrity and inflammation assays), we generated the NF datasets. Furthermore, similarity algorithms (e.g., Bayesian method and Cluster analysis) were utilized to identify similarities among the NFs and establish a provisional group(s). The grouping based on Tier 1 and/or Tier 2 testing was analyzed in relation to available Tier 3 in vivo data in order to verify if the read-across was possible and therefore support a grouping decision.

RESULTS

The measurement of the dissolution rate of the silica NFs in the oro-gastrointestinal tract and in the lysosome identified them as gradually dissolving and biopersistent NFs. For the local toxicity to intestinal epithelium (e.g. cytotoxicity, membrane integrity and inflammation), the biological results of the gastrointestinal tract models indicate that all of the silica NFs were similar with respect to the lack of local toxicity and, therefore, belong to the same group; in vivo data (although limited) confirmed the lack of local toxicity of NFs. For systemic toxicity, Tier 1 data did not identify similarity across the NFs, with results across different decision nodes being inconsistent in providing homogeneous group(s). Moreover, the available Tier 3 in vivo data were also insufficient to support decisions based upon the obtained in vitro results and relating to the toxicity of the tested NFs.

CONCLUSIONS

The information generated by the tested oral IATAs can be effectively used for similarity assessment to support a grouping decision upon the application of a hypothesis related to toxicity in the gastrointestinal tract. The IATAs facilitated a structured data analysis and, by means of the expert's interpretation, supported read-across with the available in vivo data. The IATAs also supported the users in decision making, for example, reducing the testing when the grouping was well supported by the evidence and/or moving forward to advanced testing (e.g., the use of more suitable cellular models or chronic exposure) to improve the confidence level of the data and obtain more focused information.

Gallic Acid and Gallic Acid Nanoparticle Modulate Insulin Secretion Pancreatic β-Islets against Silica Nanoparticle-Induced Oxidative Damage

Due to the increasing use of silica nanoparticles (SiNPs), their possible toxic effects on human health have undoubtedly been considered. Previous studies proved that SiNPs induced oxidative stress. Reactive oxygen species (ROS) and oxidative stress disrupt cell function and decrease insulin secretion. Therefore, this study intended to assess the effects of SiNPs on oxidative stress and insulin secretion and also the protective effects of gallic acid (GA) and gallic acid nanoparticles (NP-GA) on pancreatic β-islets. In this study, the mice islets were separated and pretreated with various concentrations of GA and NP-GA then treated with a single dose of SiNPs. The cell viability of islets examined by MTT assay and also the levels of ROS, malondialdehyde (MDA), glutathione (GSH); activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and insulin secretion were evaluated. The results of MTT assay showed that SiNPs reduced islet viability in a dose-dependent manner and also insulin secretion, induced the formation of ROS, augmented MDA amounts, and decreased GSH levels, SOD, GPx, and CAT activities. Furthermore, pretreatment of islets with GA and NP-GA significantly returned these alterations at low dose. These findings suggested that SiNPs induced oxidative stress in the pancreatic islets, which could be one of the reasons for the decrease in insulin secretion and inducing diabetes. This study also showed that low doses of GA and NP-GA boosted the antioxidant defense system in the pancreatic β-islets, preventing oxidative stress and, consequently, the progression of diabetes.

Long-term respiratory exposure to amorphous silica nanoparticles promoted systemic inflammation and progression of fibrosis in a susceptible mouse model

Exposure to amorphous silica nanoparticles (SiNPs) has increased dramatically, and concerns are growing about their potential health effects. However, their long-term systemic toxicity profile and underlying mechanisms following respiratory exposure still remains unexplored. It is well documented that the inhalation of ultrafine particles is firmly associated with adverse effects in humans. Environmental pollutants may contribute to diverse adverse effect or comorbidity in susceptible individuals. Thereby, we examined the long-term systemic effects of inhaled SiNPs using a sensitive mouse model (ApoE^-/-) fed by a western diet. Male ApoE^-/- mice were intratracheally instilled with SiNPs suspension at a dose of 1.5, 3.0 and 6.0 mg/kg·bw, respectively, once per week, 12 times in total. The histological analysis was conducted. The serum cytokine levels were quantified by RayBiotech antibody array. As a result, systemic histopathological alterations were noticed, mainly characterized by inflammation and fibrosis. More importantly, cytokine array analysis indicated the key role of mast cells accumulation in systemic inflammation and fibrosis progression induced by inhaled SiNPs. Collectively, our study firstly demonstrated that long-term exposure to inhaled SiNPs promoted the mast cell-dominated activation of inflammatory response, not only in the lung but also in heart, liver and kidney, etc., eventually leading to the progression of tissue fibrosis in ApoE^-/- mice.

A toxicological profile of silica nanoparticles

Humans are regularly exposed to silica nanoparticles in environmental and occupational contexts, and these exposures have been implicated in the onset of adverse health effects. Existing reviews on silica nanoparticle toxicity are few and not comprehensive. There are natural and synthetic sources by which crystalline and amorphous silica nanoparticles are produced. These processes influence physiochemical properties, which are factors that can dictate toxicological effects. Toxicological assessment includes exposure scenario (e.g. environmental, occupational), route of exposure, toxicokinetics, and toxicodynamics. Broader considerations include pathology, risk assessment, regulation, and treatment after injury. This review aims to consolidate the most relevant and up-to-date research in these areas to provide an exhaustive toxicological profile of silica nanoparticles.

Insight into the enhancing mechanism of silica nanoparticles on denitrification: Effect on electron transfer and microbial metabolism

Although silica nanoparticles (SiNPs) are produced in large numbers for industrial manufacturing and engineering applications, the effect of SiNPs on biotransformation in the environment is still not clear. In the current study, the effect of SiNPs in enhancing denitrification was investigated, and its mechanism was explored from the perspectives of electron transfer, microbial metabolism and bacterial community structure for the first time. Batch experiments showed that a concentration of SiNPs ranging from 0.05 to 5 g/L enhanced the bioreduction of nitrate. The mechanism study showed that SiNPs accelerated the extracellular electron transfer in the denitrification process due to their electron donating capacity, bonding action, and the secretion of more electron shuttles. During the denitrification process, SiNPs promoted metabolic activity, which mainly consists of promoting enzyme activities and electron transport system activity; these metabolic activity assays were positively correlated with SiNPs according to the structural equation modeling analysis. Moreover, SiNPs affected the composition of the microbial community, including denitrifying functional bacteria, silicon-activating bacteria and electron transfer active bacteria exhibiting a synergistic symbiosis. In addition, it was shown, by investigating two functional group-modified SiNPs, that the carboxyl modified SiNPs had the potential to be applied in nitrogen removal due to their performance and non-toxicity. This study presented a better insight into the role of SiNPs in biological transformation.

Polystyrene nanoplastics demonstrate high structural stability in vivo: A comparative study with silica nanoparticles via SERS tag labeling

Nanoplastics are regarded as inert particulate pollutants pose potential threat to organisms. It has been verified that they can penetrate biological barriers and accumulate in organisms; however, there is still a knowledge gap on the in vivo stability and degradation behaviors due to the lack of ideal analytical methods. Herein, a surface-enhanced Raman scattering (SERS) tag labeling technique was developed to study the in vivo behaviors of polystyrene (PS) nanoplastics by comparison with silica (SiO₂) nanoparticles (NPs). The labeled NPs were composed of gold NP core, attached Raman reporters as well as PS and silica shell, respectively, demonstrating strong SERS signals which were responsive to the compactness of the shells. The labeled NPs enabled the probing of in vivo structural stability of PS and silica in the liver, spleen and lung of mice after intravenous injection via the time-dependent evolution of SERS signal intensity and gold element content in the organs. The results indicated that both PS and silica model NPs retained in these organs without apparent excretion within 28 d. However, the structural stabilities of PS and silica differed dramatically as reflected by the SERS signal and tissue slice characterization. The silica shell completely degraded whereas the PS shell was still compact. Our results verified the long-term accumulation and in vivo inert property of nanoplastics, hinting that they were distinct from natural NPs and probably induce higher health risks from the aspect of the non-degradation property.

Appraisal for the Potential of Viral and Nonviral Vectors in Gene Therapy: A Review

Over the past few decades, gene therapy has gained immense importance in medical research as a promising treatment strategy for diseases such as cancer, AIDS, Alzheimer’s disease, and many genetic disorders. When a gene needs to be delivered to a target cell inside the human body, it has to pass a large number of barriers through the extracellular and intracellular environment. This is why the delivery of naked genes and nucleic acids is highly unfavorable, and gene delivery requires suitable vectors that can carry the gene cargo to the target site and protect it from biological degradation. To date, medical research has come up with two types of gene delivery vectors, which are viral and nonviral vectors. The ability of viruses to protect transgenes from biological degradation and their capability to efficiently cross cellular barriers have allowed gene therapy research to develop new approaches utilizing viruses and their different genomes as vectors for gene delivery. Although viral vectors are very efficient, science has also come up with numerous nonviral systems based on cationic lipids, cationic polymers, and inorganic particles that provide sustainable gene expression without triggering unwanted inflammatory and immune reactions, and that are considered nontoxic. In this review, we discuss in detail the latest data available on all viral and nonviral vectors used in gene delivery. The mechanisms of viral and nonviral vector-based gene delivery are presented, and the advantages and disadvantages of all types of vectors are also given.

Eryptosis is an indicator of hematotoxicity in the risk assessment of environmental amorphous silica nanoparticles exposure: The role of macromolecule corona

Silica nanoparticles (SiO₂ NPs) have been widely manufactured for various applications and unintentionally generated in various industrial processes. SiO₂ NPs exposure is potentially hazardous to human health. Incremental evidence has indicated the presence of SiO₂ NPs in systemic circulation, which warranted their interaction with blood components. Due to the obvious weakness of hemolysis in the risk assessment of environmental NPs, we for the first time use eryptosis as a sensitive indicator to assess the hematotoxicity of SiO₂ NPs. In vitro results showed that the exposure of erythrocytes to pristine SiO₂ NPs resulted in typical features of eryptosis, including oxidative stress, calcium influx, phosphatidylserine externalization and hemolysis. However, SiO₂ NPs covered with mouse plasma (SiO₂@MP) or grafted with polyvinylpyrrolidone (SiO₂@PVP) did not stimulate eryptosis. Interestingly, neither bare nor macromolecule-decolorated SiO₂ NPs caused eryptosis in our in vivo mouse model, highlighting the protective role of coronal proteins on the amelioration of SiO₂ NPs-induced hematotoxicity. These results emphasized the influences of surface modification on the toxicity of environmental NPs.

Integrative proteomics and metabolomics approach to elucidate metabolic dysfunction induced by silica nanoparticles in hepatocytes

Silica nanoparticles (SiNPs) are derived from manufactured materials and the natural environment, and they cause detrimental effects on human health via various exposure routes. The liver is proven to be a key target organ for SiNP toxicity; however, the mechanisms causing toxicity remain largely uncertain. Here, we investigated the effects of SiNPs on the metabolic spectrum in hepatocytes via integrative analyses of proteomics and metabolomics. First, a proteomic analysis was used to screen for critical proteins (including RPL3, HSP90AA1, SOD, PGK1, GOT1, and PNP), indicating that abnormal protein synthesis, protein misfolding, oxidative stress, and metabolic dysfunction may contribute to SiNP-induced hepatotoxicity. Next, metabolomic data demonstrated that SiNPs caused metabolic dysfunction by altering vital metabolites (including glucose, alanine, GSH, CTP, and ATP). Finally, a systematic bioinformatic analysis of protein-metabolite interactions showed that SiNPs disturbed glucose metabolism (glycolysis and pentose phosphate pathways, amino acid metabolism (alanine, aspartate, and glutamate), and ribonucleotide metabolism (purine and pyrimidine). These metabolic dysfunctions could exacerbate oxidative stress and lead to liver injury. Moreover, SOD, TKT, PGM1, GOT1, PNP, and NME2 may be key proteins for SiNP-induced hepatotoxicity. This study revealed the metabolic mechanisms underlying SiNP-induced hepatotoxicity and illustrated that integrative omics analyses can be a powerful approach for toxicity evaluations and risk assessments of nanoparticles.

Silica nanoparticles: Biomedical applications and toxicity

Silica nanoparticles (SiNPs) are composed of silicon dioxide, the most abundant compound on Earth, and are used widely in many applications including the food industry, synthetic processes, medical diagnosis, and drug delivery due to their controllable particle size, large surface area, and great biocompatibility. Building on basic synthetic methods, convenient and economical strategies have been developed for the synthesis of SiNPs. Numerous studies have assessed the biomedical applications of SiNPs, including the surface and structural modification of SiNPs to target various cancers and diagnose diseases. However, studies on the in vitro and in vivo toxicity of SiNPs remain in the exploratory stage, and the toxicity mechanisms of SiNPs are poorly understood. This review covers recent studies on the biomedical applications of SiNPs, including their uses in drug delivery systems to diagnose and treat various diseases in the human body. SiNP toxicity is discussed in terms of the different systems of the human body and the individual organs in those systems. This comprehensive review includes both fundamental discoveries and exploratory progress in SiNP research that may lead to practical developments in the future.

Benefits and limitations of nanomedicine treatment of brain cancers and age-dependent neurodegenerative disorders

The treatment of central nervous system (CNS) malignancies, including brain cancers, is limited by a number of obstructions, including the blood-brain barrier (BBB), the heterogeneity and high invasiveness of tumors, the inaccessibility of tissues for early diagnosis and effective surgery, and anti-cancer drug resistance. Therapies employing nanomedicine have been shown to facilitate drug penetration across the BBB and maintain biodistribution and accumulation of therapeutic agents at the desired target site. The application of lipid-, polymer-, or metal-based nanocarriers represents an advanced drug delivery system for a growing group of anti-cancer chemicals. The nanocarrier surface is designed to contain an active ligand (cancer cell marker or antibody)-binding structure which can be modified to target specific cancer cells. Glioblastoma, ependymoma, neuroblastoma, medulloblastoma, and primary CNS lymphomas were recently targeted by easily absorbed nanocarriers. The metal- (such as transferrin drug-loaded systems), polymer- (nanocapsules and nanospheres), or lipid- (such as sulfatide-containing nanoliposomes)-based nano-vehicles were loaded with apoptosis- and/or ferroptosis-stimulating agents and demonstrated promising anti-cancer effects. This review aims to discuss effective nanomedicine approaches designed to overcome the current limitations in the therapy of brain cancers and age-dependent neurodegenerative disorders. To accent current obstacles for successful CNS-based cancer therapy, we discuss nanomedicine perspectives and limitations of nanodrug use associated with the specificity of nervous tissue characteristics and the effects nanocarriers have on cognition.

Nano-Silica-Modified Concrete: A Bibliographic Analysis and Comprehensive Review of Material Properties

Several review studies have been performed on nano-silica-modified concrete, but this study adopted a new method based on scientometric analysis for the keywords’ assessment in the current research area. A scientometric analysis can deal with vast bibliometric data using a software tool to evaluate the diverse features of the literature. Typical review studies are limited in their ability to comprehensively and accurately link divergent areas of the literature. Based on the analysis of keywords, this study highlighted and described the most significant segments in the research of nano-silica-modified concrete. The challenges associated with using nano-silica were identified, and future research is directed. Moreover, prediction models were developed using data from the literature for the strength estimation of nano-silica-modified concrete. It was noted that the application of nano-silica in cement-based composites is beneficial when used up to an optimal dosage of 2–3% due to high pozzolanic reactivity and a filler effect, whereas a higher dosage of nano-silica has a detrimental influence due to the increased porosity and microcracking caused by the agglomeration of nano-silica particles. The mechanical strength might enhance by 20–25% when NS is incorporated in the optimal amount. The prediction models developed for predicting the strength of nano-silica-modified concrete exhibited good agreement with experimental data due to lower error values. This type of analysis may be used to estimate the essential properties of a material, therefore saving time and money on experimental tests. It is recommended to investigate cost-effective methods for the dispersion of nano-silica in higher concentrations in cement mixes; further in-depth studies are required to develop more accurate prediction models to predict nano-silica-modified concrete properties.

A silica-based antioxidant nanoparticle for oral delivery of Camptothecin which reduces intestinal side effects while improving drug efficacy for colon cancer treatment

Camptothecin (CPT) is a potent anticancer agent for the treatment of colorectal cancer; however, it exhibits some limitations, including poor solubility, low stability, and low bioavailability via oral administration, which restrict its usability in clinical treatments. In addition, overproduction of reactive oxygen species (ROS) during chemotherapy induces drug resistance and severe intestinal side effects. In this study, silica-installed ROS scavenging nanoparticles (siRNP) with 50-60 nm in diameter were employed to overcome the aforementioned drawbacks of CPT. The solubility of CPT was significantly improved by incorporating it into the core of the nanoparticle, forming CPT-loaded siRNP (CPT@siRNP). The anticancer activity of CPT@siRNP against colorectal cancer cells (C-26) in vitro was significantly improved as compared to free CPT through higher efficiency of intracellular internalization and induction of apoptosis. Owing to its antioxidant properties, CPT@siRNP reduced cytotoxicity to normal endothelial cells, which was in sharp contrast to the high toxicity of free CPT. Oral administration of CPT and CPT@siRNP to the C-26 tumor-bearing mice exhibited antitumor activity, accompanied by effective suppression of tumor growth. Although CPT treatment suppressed tumor progression, it caused severe side effects, including intestinal damage and significant bodyweight loss. Interestingly, such noticeable side effects were not observed in the mice treated with CPT@siRNP, and the effect of tumor growth inhibition tended to be similar to or higher than that of CPT treatment. The results obtained in this study indicate that CPT@siRNP is a potential therapeutic nanomedicine for the treatment of colon cancer. STATEMENT OF SIGNIFICANCE: Here we employed silica-containing antioxidant nanoparticle (siRNP) as promising oral delivery nanocarrier of campothecin (CPT) to treat colon cancer. The design of siRNP via covalent conjugation of antioxidant nitroxide radicals and the silanol groups in the polymer backbone contributes to a significant increase in the absorption of hydrophobic drug molecules inside the core and enhances the stability of nanoparticles in the gastrointestinal environment for oral drug delivery. CPT-loaded siRNP (CPT@siRNP) significantly improved solubility of CPT. As compared to free CTP, the CPT@siRNP treatment showed a significantly higher toxicity to colon cancer cell, inhibition of cancer cell migration, and induction of apopotosis. With the antioxidant feature, siRNP also significantly suppressed the intestinal side effects caused by CPT treatment in tumor-bearing mouse model.

Can nanomaterials support the diagnosis and treatment of human infertility? A preliminary review

Human infertilities are disorders that afflict many people all over the world. Both male and female reproductive systems must work together in a precise and coordinated manner and infertility has a wide range of problems for this system. Recent advances in nanomedicine immensely helped design the diagnostic and therapeutic approaches to alleviate human infertility in both sexes. Nanoscience has recently been used by researchers to increase the detection limit of infertility-related biomarkers via fabricating sensitive nanobiosensors for detecting follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-müllerian hormone (AMH), pregnancy-associated plasma protein-A (PAPP-A), progesterone, and testosterone. At the same time, a variety of nanostructures, including magnetic nanoparticles (i.e., zinc nanoparticles, cerium nanoparticles, gold nanoparticles, silver nanoparticles), nano-vitamins, extracellular vesicles, and spermbots, have shown promising outcomes in the treatment of human infertilities. Despite recent advancements, some nanostructures might have toxic effects on cells, especially germ cells, and must be optimized with the right ingredients, such as antioxidants, nutrients, and vitamins, to obtain the right strategy to treat and detect human infertilities. This review presents recent developments in nanotechnology regarding impairments still faced by human infertility. New perspectives for further use of nanotechnology in reproductive medicine studies are also discussed. In conclusion, nanotechnology, as a tool for reproductive medicine, has been considered to help overcome current impairments.

Immunotherapeutic nanoparticles: From autoimmune disease control to the development of vaccines

The development of nanoparticles (NPs) with potential therapeutic uses represents an area of vast interest in the scientific community during the last years. Recently, the pandemic caused by COVID-19 motivated a race for vaccines creation to overcome the crisis generated. This is a good demonstration that nanotechnology will most likely be the basis of future immunotherapy. Moreover, the number of publications based on nanosystems has significantly increased in recent years and it is expected that most of these developments can go on to experimentation in clinical stages soon. The therapeutic use of NPs to combat different diseases such as cancer, allergies or autoimmune diseases will depend on their characteristics, their targets, and the transported molecules. This review presents an in-depth analysis of recent advances that have been developed in order to obtain novel nanoparticulate based tools for the treatment of allergies, autoimmune diseases and for their use in vaccines. Moreover, it is highlighted that by providing targeted delivery an increase in the potential of vaccines to induce an immune response is expected in the future. Definitively, the here gathered analysis is a good demonstration that nanotechnology will be the basis of future immunotherapy.

Nanotechnology in Cosmetics and Cosmeceuticals—A Review of Latest Advancements

Nanotechnology has the potential to generate advancements and innovations in formulations and delivery systems. This fast-developing technology has been widely exploited for diagnostic and therapeutic purposes. Today, cosmetic formulations incorporating nanotechnology are a relatively new yet very promising and highly researched area. The application of nanotechnology in cosmetics has been shown to overcome the drawbacks associated with traditional cosmetics and also to add more useful features to a formulation. Nanocosmetics and nanocosmeceuticals have been extensively explored for skin, hair, nails, lips, and teeth, and the inclusion of nanomaterials has been found to improve product efficacy and consumer satisfaction. This is leading to the replacement of many traditional cosmeceuticals with nanocosmeceuticals. However, nanotoxicological studies on nanocosmeceuticals have raised concerns in terms of health hazards due to their potential skin penetration, resulting in toxic effects. This review summarizes various nanotechnology-based approaches being utilized in the delivery of cosmetics as well as cosmeceutical products, along with relevant patents. It outlines their benefits, as well as potential health and environmental risks. Further, it highlights the regulatory status of cosmeceuticals and analyzes the different regulatory guidelines in India, Europe, and the USA and discusses the different guidelines and recommendations issued by various regulatory authorities. Finally, this article seeks to provide an overview of nanocosmetics and nanocosmeceuticals and their applications in cosmetic industries, which may help consumers and regulators to gain awareness about the benefits as well as the toxicity related to the continuous and long-term uses of these products, thus encouraging their judicious use.

Silica nanoparticles induce pulmonary autophagy dysfunction and epithelial-to-mesenchymal transition via p62/NF-κB signaling pathway

It has been reported that silica nanoparticles (SiNPs) could cause epithelial-to-mesenchymal transition (EMT), but the specific mechanism is still unclear. Thus, the purpose of this study was to investigate the underlying mechanisms of pulmonary EMT after subacute exposure to SiNPs. The results showed intratracheal instillation of SiNPs increased the pulmonary MDA content, while decreased the activity of SOD and GSH-Px in rats. Western blot analysis demonstrated that SiNPs induced autophagy dysfunction via the upregulation of p62. Meanwhile, the inflammation cytokines (TNF-α, IL-18, IL-1β) were released in rat lung. Immunohistochemistry and western blot assays both showed that SiNPs could regulate the related protein biomarkers of EMT through decreasing E-cadherin and increasing vimentin in a dose-dependent manner. Besides, SiNPs activated the proteins expression involved in p62/NF-κB signaling pathway, whereas the pulmonary EMT induced by SiNPs was significantly dampened after the knock down of p62. In this study, we illustrated that subacute exposure to SiNPs could trigger the autophagy dysfunction and pulmonary inflammation, further lead to EMT via activating the p62/NF-κB signaling pathway. Our findings provide new molecular evidence for SiNPs-induced pulmonary toxicity.

Skin interaction, permeation, and toxicity of silica nanoparticles: Challenges and recent therapeutic and cosmetic advances

Silica nanoparticles (SNPs) received more attention with the emergence of nanotechnology with the aim and promise of becoming innovative drug delivery systems. They have been fulfilling this objective with excellence and nowadays they play a central role in biomedical applications. New SNPs application routes are being explored such as the epidermal, dermal, and transdermal routes. With that, novel models of synthesis, functionalization, and applications constantly appear. However, it is essential that such innovations are accompanied by in-depth studies on permeation, biodistribution, metabolization, and elimination of the generated by-products. Such studies are still incipient, if not rare. This article reviews significant findings on SNPs and their skin interactions. An extensive literature review on SNPs synthesis and functionalization methodologies was performed, as well as on the skin characteristics, skin permeation mechanisms, and in vivo toxicity assessments. Furthermore, studies of the past 5 years on the main therapeutic and cosmetic products employing SNPs, with greater emphasis on in vivo and ex vivo studies were included.

Nanoparticles: Excellent Materials Yet Dangerous When They Become Airborne

Since the rise and rapid development of nanoscale science and technology in the late 1980s, nanomaterials have been widely used in many areas including medicine, electronic products, crafts, textiles, and cosmetics, which have provided a lot of convenience to people's life. However, while nanomaterials have been fully utilized, their negative effects, also known as nano pollution, have become increasingly apparent. The adverse effects of nanomaterials on the environment and organisms are mainly based on the unique size and physicochemical properties of nanoparticles (NPs). NPs, as the basic unit of nanomaterials, generally refer to the ultrafine particles whose spatial scale are defined in the range of 1-100 nm. In this review, we mainly introduce the basic status of the types and applications of NPs, airborne NP pollution, and the relationship between airborne NP pollution and human diseases. There are many sources of airborne NP pollutants, including engineered nanoparticles (ENPs) and non-engineered nanoparticles (NENPs). The NENPs can be further divided into those generated from natural activities and those produced by human activities. A growing number of studies have found that exposure to airborne NP pollutants can cause a variety of illnesses, such as respiratory diseases, cardiovascular diseases, and neurological disorders. To deal with the ever increasing numbers and types of NPs being unleashed to the air, we believe that extensive research is needed to provide a comprehensive understanding of NP pollution hazards and their impact mechanisms. Only in this way can we find the best solution and truly protect the safety and quality of life of human beings.

Recent Advances in Synthetic and Natural Biomaterials-Based Therapy for Bone Defects

Synthetic and natural biomaterials are a promising alternative for the treatment of critical-sized bone defects. Several parameters such as their porosity, surface, and mechanical properties are extensively pointed out as key points to recapitulate the bone microenvironment. Many biomaterials with this pursuit are employed to provide a matrix, which can supply the specific environment and architecture for an adequate bone growth. Nevertheless, some queries remain unanswered. This review discusses the recent advances achieved by some synthetic and natural biomaterials to mimic the native structure of bone and the manufacturing technology applied to obtain biomaterial candidates. The focus of this review is placed in the recent advances in the development of biomaterial-based therapy for bone defects in different types of bone. In this context, this review gives an overview of the potentialities of synthetic and natural biomaterials: polyurethanes, polyesters, hyaluronic acid, collagen, titanium, and silica as successful candidates for the treatment of bone defects.

Oxidative metabolism in the cardiorespiratory system after an acute exposure to nickel-doped nanoparticles in mice

There is an increasing concern over the harmful effects that metallic nanoparticles (NP) may produce on human health. Due to their redox properties, nickel (Ni) and Ni-containing NP are particularly relevant. Hence, the aim of this study was to establish the toxicological mechanisms in the cardiorespiratory oxidative metabolism initiated by an acute exposure to Ni-doped-NP. Mice were intranasally instilled with silica NP containing Ni (II) (Ni-NP) (1 mg Ni (II)/kg body weight) or empty NP as control, and 1 h after exposure lung, plasma, and heart samples were obtained to assess the redox metabolism. Results showed that, NP were mainly retained in the lungs triggering a significantly increased tissue O₂ consumption rate, leading to Ni-NP-increased reactive oxygen species production by NOX activity, and mitochondrial H₂O₂ production rate. In addition, an oxidant redox status due to an altered antioxidant system showed by lung GSH/GSSG ratio decreased, and SOD activity increased, resulting in an increased phospholipid oxidation. Activation of circulating polymorphonuclear leukocytes, along with GSH/GSSG ratio decreased, and phospholipid oxidation were found in the Ni-NP-group plasma samples. Consequently, in distant organs such as heart, Ni-NP inhalation alters the tissue redox status. Our results showed that the O₂ metabolism analysis is a critical area of study following Ni-NP inhalation. Therefore, this work provides novel data linking the redox metabolisms alterations elicited by exposure to Ni (II) adsorbed to NP and cardiorespiratory toxicity.

Endocrine disrupting chemicals: Friend or foe to brown and beige adipose tissue?

The effects of Endocrine Disrupting Chemicals (EDCs) on the current obesity epidemic is a growing field of interest. Numerous EDCs have shown the potential to alter energy metabolism, which may increase the risk of obesity, in part, through direct actions on adipose tissue. While white adipose tissue has historically been the primary focus of this work, evidence of the EDC-induced disruption of brown and beige adipose tissues continues to build. Both brown and beige fat are thermogenic adipose depots rich in mitochondria that dispense heat when activated. Due to these properties, brown and beige fat are implicated in metabolic diseases such as obesity, diabetes, and cachexia. This review delves into the current literature of different EDCs, including bisphenols, dioxins, air pollutants, phthalates, and phytochemicals. The possible implications that these EDCs have on thermogenic adipose tissues are covered. This review also introduces the possibility of using brown and beige fat as a therapeutic target organ by taking advantage of some of the properties of EDCs. Collectively, we provide a comprehensive discussion of the evidence of EDC disruption in white, brown, and beige fat and highlight gaps worthy of further exploration.

Ecotoxicity of silica nanoparticles in aquatic organisms: An updated review

This review aims to (i) provide a current overview of the main characteristics of SiNP (physical and chemical properties, applications, and emissions), (ii) evaluate the scientific production up to date concerning SiNP, with focus on their toxic effects, through a bibliometric analysis, (iii) describe the main toxic mechanisms of SiNP, (iv) assess the current knowledge about ecotoxicity of SiNP on aquatic organisms (marine and freshwater), and (v) identify the main gaps in the knowledge of SiNP toxicity from an environmentally point of view. The scientific production of SiNP concerning their chemical and physical characteristics has increased exponentially. However, little information is available regarding their ecotoxicity. Particle functionalization is a key factor that reduces SiNP toxicity. Most of the studies employed standard species as test organisms, being the local/native ones poorly represented. Further studies employing long-term exposures and environmentally relevant concentrations are needed to deepen the knowledge about this emergent pollutant.

The revolution of cosmeceuticals delivery by using nanotechnology: A narrative review of advantages and side effects

BACKGROUND

The qualified and paradigm jump in the formulation and production of cosmeceuticals refer in some way to the great revolution in nanotechnology. Nowadays, the industry of nano-formulated cosmeceuticals plays a significant and essential role in the evolution and growth of the pharmaceutical industries. This review manuscript focuses on the use of nanocarriers in delivering the cosmetic agents into the target area such as skin, hair, and nails.

METHODS

Many steps were performed in the preparation of this review including identification of different classes of nanocarriers for delivery of nanocosmeceuticals, literature survey of relevantstudies regarding the applications of nanotechnology in cosmeceuticals and their toxicological effects.

RESULTS

When nanoparticles introduced in the cosmetic industry, the quality and the elegance of the final products were raised significantly. Sadly, this revolution is accompanied by many health hazards as these tiny molecules can penetrate intact skin barriers and cause undesired effects. Cosmeceuticals with nanotechnology include sunscreens, hair cleansing products, nail products, and agents fighting fine lines.

CONCLUSIONS

The expansion and growth of the cosmetic industry and the introduction of nanotechnology in cosmeceuticals industry necessitates the urgent need for scientific research investigating their efficacy, safety profile and use.

Nanosystems in Cosmetic Products: A Brief Overview of Functional, Market, Regulatory and Safety Concerns

Nanosystems exhibit various innovative physico-chemical properties as well as a range of cosmetic functions, including increased skin retention for loaded compounds. The worldwide nano-market has therefore been consistently extensive in recent decades. This review summarizes the most important properties of nanosystems that are employed in cosmetics, including composition, functions and interactions with skin, with particular attention being paid to marketed products. Moreover, the worldwide regulatory landscape of nanomaterials used as cosmetic ingredients is considered, and the main safety concerns are indicated. In general, advanced physico-chemical characterization is preliminarily needed to assess the safety of nanomaterials for human health and the environment. However, there is currently a shortfall in global legislation as a universally accepted and unambiguous definition of a nanomaterial is still lacking. Therefore, each country follows its own regulations. Anyhow, the main safety concerns arise from the European context, which is the most restrictive. Accordingly, the poor dermal permeation of nanomaterials generally limits their potential toxic effects, which should be mainly ascribed to unwanted or accidental exposure routes.

Dealing with MDR bacteria and biofilm in the post-antibiotic era: Application of antimicrobial peptides-based nano-formulation

The rapid development of multidrug-resistant (MDR) bacteria due to the improper and overuse of antibiotics and the ineffective performance of antibiotics against the difficult-to-treat biofilm-related infections (BRIs) have urgently called for alternative antimicrobial agents and strategies in combating bacterial infections. Antimicrobial peptides (AMPs), owing to their compelling antimicrobial activity against MDR bacteria and BRIs without causing bacteria resistance, have attracted extensive attention in the research field. With the development of nanomaterial-based drug delivery strategies, AMPs-based nano-formulations have significantly improved the therapeutic effects of AMPs by ameliorating their hydrolytic stability, half-life in vivo, and solubility as well as reducing the cytotoxicity and hemolysis, etc. This review has comprehensively summarized the application AMPs-based nano-formulation in various bacterial infections models, including bloodstream infections (specifically sepsis), pulmonary infections, chronic wound infections, gastrointestinal infections, among others. The design of the nanomaterial-based drug delivery systems and the therapeutic effects of the AMPs-based nano-formulations in literature have been categorized and in details discussed. Overall, this review provides insights into the advantages and disadvantages of the current developed AMPs-based nano-formulations in literature for the treatment of bacterial infections, bringing inspirations and suggestions for their future design in the way towards clinical translation.

Photocatalytic Detoxification of Some Insecticides in Aqueous Media Using TiO2 Nanocatalyst

The present study was performed to fabricate a titanium dioxide (TiO₂) nanocatalyst with proper characteristics for the removal of some insecticides (dimethoate and methomyl) from aqueous media. A TiO₂ catalyst of regular (TiO₂-commercial-/H₂O₂/UV) or nano (TiO₂-synthesized-/H₂O₂/UV) size was employed as an advanced oxidation process by combining it with H₂O₂ under light. Moreover, the total detoxification of insecticides after treatment with the most effective system (TiO₂(s)/H₂O₂/UV) was also investigated through exploring the biochemical alterations and histopathological changes in the liver and kidneys of the treated rats. Interestingly, the present study reported that degradation rates of the examined insecticides were faster using the TiO₂ catalyst of nano size. Complete degradation of the tested insecticides (100%) was achieved under the TiO₂(s)/H₂O₂/UV system after 320 min of irradiation. The half-life values of the tested insecticides under H₂O₂/TiO₂(c)/UV were 43.86 and 36.28 for dimethoate and methomyl, respectively, whereas under the H₂O₂/TiO₂(c)/UV system, the half-life values were 27.72 and 19.52 min for dimethoate and methomyl, respectively. On the other hand, no significant changes were observed in the biochemical and histopathological parameters of rats administrated with water treated with TiO₂(s)/H₂O₂/UV compared to the control, indicating low toxicity of the TiO₂ nanocatalyst-. Altogether, the advanced oxidation processes using TiO₂ nanocatalyst can be considered as a promising and effective remediation technology for the complete detoxification of methomyl and dimethoate in water. However, further future research is needed to identify the possible breakdown products and to verify the safety of the used nanomaterials.

Genotoxicity evaluation of silica nanoparticles in murine: a systematic review and meta-analysis

Silica nanoparticles (SiNPs) have been widely used in nanotechnology, and more attention has been paid to their safety evaluation. However, there are still inconsistent conclusions about the genotoxicity of SiNPs. A systematic review was conducted to explore whether SiNPs have genotoxicity followed by a meta-analysis of in vivo and in vitro murine genotoxicity tests. A total of 26 eligible studies were identified in this meta-analysis through a detailed process of inclusion and exclusion, which included 9 in vivo studies, 15 in vitro studies, and 2 in both. The results of in vitro studies showed that SiNPs exposure significantly increased the indicators of the comet assay, such as tail DNA content (T DNA%), tail length (TL), and olive tail moment (OTM). Indicators of mutagenicity had not been affected in vitro studies, such as mutation frequency (MF) and micronucleus (MN) frequency. There was a significant increase in MN frequency, but there was no influence on T DNA% in vivo. Results of subgroup analysis indicated that size and treatment time of SiNPs were the associated factors in vitro genotoxicity. The size of SiNPs, <21 nm, induced more DNA damage than larger sized SiNPs. It could induce MN formation when the treatment time of SiNPs was <12 h, and even more DNA damage when the exposure time over 12 h. SiNPs can induce genotoxicity both in vivo and in vitro. Comet assay may be more sensitive to detect in vitro genotoxicity, and MN frequency may be more suitable to detect in vivo genotoxicity.

Skin Sensitization Potential and Cellular ROS-Induced Cytotoxicity of Silica Nanoparticles

Nowadays, various industries using nanomaterials are growing rapidly, and in particular, as the commercialization and use of nanomaterials increase in the cosmetic field, the possibility of exposure of nanomaterials to the skin of product producers and consumers is increasing. Due to the unique properties of nanomaterials with a very small size, they can act as hapten and induce immune responses and skin sensitization, so accurate identification of toxicity is required. Therefore, we selected silica nanomaterials used in various fields such as cosmetics and biomaterials and evaluated the skin sensitization potential step-by-step according to in-vitro and in-vivo alternative test methods. KeratinoSens^TM cells of modified keratinocyte and THP-1 cells mimicking dendritic-cells were treated with silica nanoparticles, and their potential for skin sensitization and cytotoxicity were evaluated, respectively. We also confirmed the sensitizing ability of silica nanoparticles in the auricle-lymph nodes of BALB/C mice by in-vivo analysis. As a result, silica nanoparticles showed high protein binding and reactive oxygen species (ROS) mediated cytotoxicity, but no significant observation of skin sensitization indicators was observed. Although more studies are needed to elucidate the mechanism of skin sensitization by nanomaterials, the results of this study showed that silica nanoparticles did not induce skin sensitization.