Nanotoxicology and Nanomedicine: The Yin and Yang of Nano-Bio Interactions for the New Decade.

Nanotoxicology and nanomedicine are two sub-disciplines of nanotechnology focusing on the phenomena, mechanisms, and engineering at the nano-bio interface. For the better part of the past three decades, these two disciplines have been largely developing independently of each other. Yet recent breakthroughs in microbiome research and the current COVID-19 pandemic demonstrate that holistic approaches are crucial for solving grand challenges in global health. Here we show the Yin and Yang relationship between the two fields by highlighting their shared goals of making safer nanomaterials, improved cellular and organism models, as well as advanced methodologies. We focus on the transferable knowledge between the two fields as nanotoxicological research is moving from pristine to functional nanomaterials, while inorganic nanomaterials - the main subjects of nanotoxicology - have become an emerging source for the development of nanomedicines. We call for a close partnership between the two fields in the new decade, to harness the full potential of nanotechnology for benefiting human health and environmental safety.

Reduced graphene oxide composites and its real-life application potential for in-situ crude oil removal.

Crude oil pollution can cause severe and long-term ecological damage and oil cleanup has become a worldwide challenge. Conventional treatment strategies like in-situ burning, manual skimmer and bioremediation were labor-intensive and time-consuming. The high viscosity of crude oil also posed difficulty for traditional absorbents. Herein, to address these limitations, we designed and fabricated a floating absorbent that was comprised of reduced graphene oxide (RGO), melamine sponge (MS), and a 3D-printed mounting platform. Through a facile one-pot hydrothermal method, graphene oxide (GO) was simultaneously reduced to RGO and loaded in MS (RGO-MS). The resulted RGO-MS composites possess desirable hydrophobicity/oleophilicity for oil absorption with a water contact angle of 122°. The effective light-to-heat conversion allowed the RGO-MS composite to absorb approximately 95 times its own weight of crude oil within 12 min under light irradiation. A 3D-printed mounting platform for RGO-MS composites was further fabricated to improve its applicability and allow easy retrieval. Taking advantages of the RGO's hydrophobicity/oleophilicity and photothermal property, the floating ability of MS, this study demonstrated the real-life applicability of RGO-MS composites for in-situ crude oil cleanup.

Mitigating Human IAPP Amyloidogenesis In Vivo with Chiral Silica Nanoribbons.

Amyloid fibrils generally display chirality, a feature which has rarely been exploited in the development of therapeutics against amyloid diseases. This study reports, for the first time, the use of mesoscopic chiral silica nanoribbons against the in vivo amyloidogenesis of human islet amyloid polypeptide (IAPP), the peptide whose aggregation is implicated in type 2 diabetes. The thioflavin T assay and transmission electron microscopy show accelerated IAPP fibrillization through elimination of the nucleation phase and shortening of the elongation phase by the nanostructures. Coarse-grained simulations offer complementary molecular insights into the acceleration of amyloid aggregation through their nonspecific binding and directional seeding with the nanostructures. This accelerated IAPP fibrillization translates to reduced toxicity, especially for the right-handed silica nanoribbons, as revealed by cell viability, helium ion microscopy, as well as zebrafish embryo survival, developmental, and behavioral assays. This study has implicated the potential of employing chiral nanotechnologies against the mesoscopic enantioselectivity of amyloid proteins and their associated diseases.

Oil refinery wastewater treatment in the Niger Delta, Nigeria: current practices, challenges, and recommendations.

The extensive oil exploration has led to a series of environmental issues in the Niger Delta, Nigeria, over the years. Aside from oil spill, insufficient wastewater treatment of oil refineries and the discharged effluents become another potential source of pollution that has not received enough attention from the government and the public. Through reviewing the current oil refinery wastewater treatment processes and the discharge standards of wastewater effluents in Nigeria, we aimed to raise the awareness of the shortcomings of the current wastewater treatment technology and to discuss the consequences of insufficient treatment to the environment. This article further discussed the use of nanotechnology as a potential upgrade to the conventional treatment technologies as it has shown its capacity of removing persistent organic pollutants (POPs) or converting hazardous components to environmentally friendly derivatives. It should also prove beneficial to the key stakeholders involved in the exploration of crude oil in the region to consider optimization of oil refinery wastewater treatment processes through integration of emerging technologies.

Transcriptional and Physiological Responses to Nutrient Loading on Toxin Formation and Photosynthesis in Microcystis Aeruginosa FACHB-905.

An important goal of understanding harmful algae blooms is to determine how environmental factors affect the growth and toxin formation of toxin-producing species. In this study, we investigated the transcriptional responses of toxin formation gene (mcyB) and key photosynthesis genes (psaB, psbD and rbcL) of Microcystis aeruginosa FACHB-905 in different nutrient loading conditions using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR). Three physio-biochemical parameters (malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH)) were also evaluated to provide insight into the physiological responses of Microcystis cells. We observed an upregulation of mcyB gene in nutrient-deficient conditions, especially in nitrogen (N) limitation condition, and the transcript abundance declined after the nutrient were resupplied. Differently, high transcription levels were seen in phosphorus (P) deficient treatments for key photosynthesis genes throughout the culture period, while those in N-deficient cells varied with time, suggesting an adaptive regulation of Microsystis cells to nutrient stress. Increased contents of antioxidant enzymes (SOD and GSH) were seen in both N and P-deficient conditions, suggesting the presence of excess amount of free radical generation caused by nutrient stress. The amount of SOD and GSH continued to increase even after the nutrient was reintroduced and a strong correlation was seen between the MDA and enzyme activities, indicating the robust effort of rebalancing the redox system in Microcystis cells. Based on these transcriptional and physiological responses of M. aeruginosa to nutrient loading, these results could provide more insight into Microcystis blooms management and toxin formation regulation.

Use of a high-throughput screening approach coupled with in vivo zebrafish embryo screening to develop hazard ranking for engineered nanomaterials.

Because of concerns about the safety of a growing number of engineered nanomaterials (ENM), it is necessary to develop high-throughput screening and in silico data transformation tools that can speed up in vitro hazard ranking. Here, we report the use of a multiparametric, automated screening assay that incorporates sublethal and lethal cellular injury responses to perform high-throughput analysis of a batch of commercial metal/metal oxide nanoparticles (NP) with the inclusion of a quantum dot (QD1). The responses chosen for tracking cellular injury through automated epifluorescence microscopy included ROS production, intracellular calcium flux, mitochondrial depolarization, and plasma membrane permeability. The z-score transformed high volume data set was used to construct heat maps for in vitro hazard ranking as well as showing the similarity patterns of NPs and response parameters through the use of self-organizing maps (SOM). Among the materials analyzed, QD1 and nano-ZnO showed the most prominent lethality, while Pt, Ag, SiO2, Al2O3, and Au triggered sublethal effects but without cytotoxicity. In order to compare the in vitro with the in vivo response outcomes in zebrafish embryos, NPs were used to assess their impact on mortality rate, hatching rate, cardiac rate, and morphological defects. While QDs, ZnO, and Ag induced morphological abnormalities or interfered in embryo hatching, Pt and Ag exerted inhibitory effects on cardiac rate. Ag toxicity in zebrafish differed from the in vitro results, which is congruent with this material's designation as extremely dangerous in the environment. Interestingly, while toxicity in the initially selected QD formulation was due to a solvent (toluene), supplementary testing of additional QDs selections yielded in vitro hazard profiling that reflect the release of chalcogenides. In conclusion, the use of a high-throughput screening, in silico data handling and zebrafish testing may constitute a paradigm for rapid and integrated ENM toxicological screening.