Identifying resistance molecules in TiO2 nanoparticle-tolerant strains to facilitate the development of strategies for combating TiO2 nanoparticle pollution

The severity of environmental pollution caused by TiO2 nanoparticles (nTiO2) is increasing, highlighting the urgent need for the development of strategies to combat nTiO2 pollution. Insights into resistance molecules from nTiO2-tolerant strains may facilitate such development. In this study, we utilized multi-omics, genetic manipulation, physiological and biochemical experiments to identify relevant resistance molecules in two strains (Physarum polycephalum Z259 and T83) tolerated to mixed-phase nTiO2 (MPnTiO2). We discovered that a competing endogenous RNA (ceRNA) network, comprising one long non-coding RNA (lncRNA), four microRNAs, and nine mRNAs, influenced metabolic rearrangement and was associated with significant resistance in these strains. Additionally, we found that the lncRNA in the ceRNAs network and certain small-weight metabolites associated with the ceRNA exhibited notable mitigation effects not only against MPnTiO2 but also against other types of nTiO2 with broad species applicability (they significantly improved the resistance of several non-nTiO2-tolerant cells/organisms in the laboratory and reduced cell damage of non-nTiO2-tolerant cells/organisms in highly suspected nTiO2-polluted areas of the real world). In summary, this study deepens our understanding of nTiO2-tolerant strains, provides valuable insights into resistance molecules in these strains, and facilitates the development of strategies to combat nTiO2 pollution.

Microfluidic-based skin-on-chip systems for safety assessment of nanomaterials

The skin is the body's largest organ, continuously exposed to and affected by natural and anthropogenic nanomaterials (materials with external and internal dimensions in the nanoscale range). This broad spectrum of insults gives rise to irreversible health effects (from skin corrosion to cancer). Organ-on-chip systems can recapitulate skin physiology with high fidelity and potentially revolutionize the safety assessment of nanomaterials. Here, we review current advances in skin-on-chip models and their potential to elucidate biological mechanisms. Further, strategies are discussed to recapitulate skin physiology on-chip, improving control over nanomaterials exposure and transport across cells. Finally, we highlight future opportunities and challenges from design and fabrication to acceptance by regulatory bodies and industry.

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

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

Cytotoxicity of Metal-Based Nanoparticles: From Mechanisms and Methods of Evaluation to Pathological Manifestations

Metal-based nanoparticles (NPs) are particularly important tools in tissue engineering-, drug carrier-, interventional therapy-, and biobased technologies. However, their complex and varied migration and transformation pathways, as well as their continuous accumulation in closed biological systems, cause various unpredictable toxic effects that threaten human and ecosystem health. Considerable experimental and theoretical efforts have been made toward understanding these cytotoxic effects, though more research on metal-based NPs integrated with clinical medicine is required. This review summarizes the mechanisms and evaluation methods of cytotoxicity and provides an in-depth analysis of the typical effects generated in the nervous, immune, reproductive, and genetic systems. In addition, the challenges and opportunities are discussed to enhance future investigations on safer metal-based NPs for practical commercial adoption.

Ovarian toxicity of nanoparticles

The ovary is a highly important organ for female reproduction. The main functions include sex steroid hormone synthesis, follicular development, and achievement of oocyte meiotic and development competence for proper fertilization. Nanoparticle (NP) exposure is becoming unavoidable because of its wide use in different products, including cosmetics, food, health, and personal care products. Studies examining different nonreproductive tissues or systems have shown that characteristics such as the size, shape, core material, agglomeration, and dissolution influence the effects of NPs. However, most studies evaluating NP-mediated reproductive toxicity have paid little or no attention to the influence of the physicochemical characteristics of NP on the observed effects. As accumulating evidence indicates that NP may reach the ovary to impair proper functions, this review summarizes the available data on NP accumulation in ovarian tissue, as well as data describing toxicity to ovarian functions, including sex steroid hormone production, follicular development, oocyte quality, and fertility. Due to their toxicological relevance, this review also describes the main physicochemical characteristics involved in NP toxicity and the importance of considering NP physicochemical characteristics as factors influencing the ovarian toxicity of NPs. Finally, this review summarizes the main mechanisms of toxicity described in ovarian cells.

Upshift of the d Band Center toward the Fermi Level for Promoting Silver Ion Release, Bacteria Inactivation, and Wound Healing of Alloy Silver Nanoparticles

Silver (Ag)-based nanoparticles (NPs) with a high potential of Ag⁺ release have been known to be capable of promoting bacteria inactivation and the wound healing process; however, keeping a steady flux of high levels of Ag⁺ in Ag-based NPs is still challenging. Herein, a novel strategy in terms of altering the intrinsic electronic structure of Ag NPs was attempted to facilitate Ag oxidation and boost the Ag⁺ flux, as results of improved antibacterial and wound healing performance of Ag NPs. Gold (Au), platinum (Pt), and palladium (Pd) were doped into Ag NPs to tune their d band centers to upshift toward the Fermi level, and the formed Pd-Ag alloy NPs showed the largest shift, followed by Pt-Ag and Au-Ag NPs, as determined by density function theory calculation and ultraviolet photoemission spectroscopy measurement. Further X-ray photoelectron spectroscopy analysis indicates that a larger upshift could induce less electron filling in the antibonding orbital and a higher Ag oxidation level, leading to the more remarkable Ag⁺ release as determined by inductively coupled plasma optical emission spectrometry. All these alloy Ag NPs could more efficiently inhibit bacterial growth and accelerate the wound healing process than pure Ag NPs, and their antibacterial activity and wound healing performance were progressively proportional to the upshift values of the d band center. Taken together, tuning the d band center to upshift toward the Fermi level becomes a feasible strategy for designing therapeutic Ag-based NPs with a promising antibacterial and wound healing performance.