A cascade of in situ conversion of bicarbonate to CO_(2) and CO_(2) electroreduction in a flow cell with a Ni-N-S catalyst

Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electrochemical reduction of HCO_(3)^(-)is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO_(3)^(-)to CO_(2) and CO_(2) electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni center,the CO_(2)electroreduction(CO_(2)ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing^(*)H over N and boosting the first proton coupled electron transfer process of CO_(2)ER,i.e.,^(*)+e^(-)+^(*)H+^(*)CO_(2)→^(*)COOH.As a result,the obtained catalyst exhibits a high faradaic efficiency(FE_(CO)~98%)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h^(-1),outcompeting most of the reported Ni SACs.More importantly,an extremely high FECOof 90%is achieved at 50 mA cm^(-2)in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO_(2)ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO_(3)^(-)to high-value chemicals.

Surface regulated Ni nanoparticles on N-doped mesoporous carbon as an efficient electrocatalyst for CO_(2)reduction

Low cost,highly selective and efficient electrocatalysts for CO_(2)reduction reaction(CO_(2)RR)is crucial for lowering the global carbon footprint and mitigating energy shortages.Here,we first report a highly selective and efficient electrocatalyst for CO_(2)RR to CO using a surface-regulated Ni nanoparticles supported on N-doped CMK-3(N,O-Ni/CMK3).Compared with most Ni metal catalysts previously reported with severe competitive hydrogen evolution during the CO_(2)RR,the N,O-Ni/CMK3 catalyst presents a superior CO faradaic efficiency of about 97%,a high CO partial current density(13.01 mA cm^(-1))and turnover frequency(4.25 s^(–1)).The comprehensive characterization provides evidence that the N,O co-regulated Ni acts as the active center.Taking advantage of the N,O co-regulated chemical environment,N,O-Ni/CMK3 also displays a decent stability at negative potentials.Our work paves a novel approach for developing transition metal catalysts for CO_(2)RR with enhanced activity and selectivity via regulating surface chemical environment.

Modulating GSK3β Phosphorylation:Bio-Corona Protective Effects Against Silica Nanoparticle-Induced Neurotoxicity

Nanotechnology has revolutionized many aspects of daily life,simultaneously increasing human exposure to nanoparticles(NPs).This exposure can come from various sources,such as environmental factors(e.g.,water,air,food chain),and consumer products(cosmetics,medicines,industrial chemicals).Once inside the body,NPs interact with biomolecules,predominantly proteins,and undergo changes during their integration and clearance.

Cytotoxicity and autophagy induction by graphene quantum dots with different functional groups

Graphene quantum dots(GQDs) possess great potential in various applications due to their superior physicochemical properties and wide array of available surface modifications.However, the toxicity of GQDs has not been systematically assessed, thus hindered their further development; especially, the risk of surface modifications of GQDs is largely unknown. In this study, we employed a lung carcinoma A549 cells as the model to investigate the cytotoxicity and autophagy induction of three types GQDs, including cGQDs(COOH-GQDs), hGQDs(OH-GQDs), and aGQDs(NH_2-GQDs). The results showed hGQDs was the most toxic, as significant cell death was induced at the concentration of 100 μg/mL,determining by WST-1 assay as well as Annexin-V-FITC/PI apoptosis analysis, whereas cGQDs and aGQDs were non-cytotoxic within the measured concentration. Autophagy detection was performed by TEM examination, LC3 fluorescence tracking, and Westernblot. Both aGQDs and hGQDs induced cellular autophagy to various degrees except for cGQDs. Further analysis on autophagy pathways indicated all GQDs significantly activated p-p38 MAPK; p-ERK1/2 was inhibited by aGQDs and hGQDs but activated by c GQDs. p-JNK was inhibited by aGQDs and c GQDs, while activated by hGQDs. Simultaneously, Akt was activated by hGQDs but inhibited by aGQDs. Inhibition of autophagy by 3-MA significantly increased the cytotoxicity of GQDs, suggesting that autophagy played a protective role against the toxicity of GQDs. In conclusion, c GQDs showed excellent biocompatibility and may be considered for biological applications. Autophagy induction may be included in the health risk assessment of GQDs as it reflects the stress status which may eventually lead to diseases.

Nano-bio interactions: the implication of size-dependent biological effects of nanomaterials

Due to their many advantageous properties,nanomaterials(NMs)have been utilized in diverse consumer goods,industrial products,and for therapeutic purposes.This situation leads to a constant risk of exposure and uptake by the human body,which are highly dependent on nanomaterial size.Consequently,an improved understanding of the interactions between different sizes of nanomaterials and biological systems is needed to design safer and more clinically relevant nano systems.We discuss the sizedependent effects of nanomaterials in living organisms.Upon entry into biological systems,nanomaterials can translocate biological barriers,distribute to various tissues and elicit different toxic effects on organs,based on their size and location.The association of nanomaterial size with physiological structures within organs determines the site of accumulation of nanoparticles.In general,nanomaterials smaller than 20 nm tend to accumulate in the kidney while nanomaterials between 20 and 100 nm preferentially deposit in the liver.After accumulating in organs,nanomaterials can induce inflammation,damage structural integrity and ultimately result in organ dysfunction,which helps better understand the size-dependent dynamic processes and toxicity of nanomaterials in organisms.The enhanced permeability and retention effect of nanomaterials and the utility of this phenomenon in tumor therapy are also highlighted.

Advancing intestinal organoid technology to decipher nano-intestine interactions and treat intestinal disease

With research burgeoning in nanoscience and nanotechnology,there is an urgent need to develop new biological models that can simulate native structure,function,and genetic properties of tissues to evaluate the adverse or beneficial effects of nanomaterials on a host.Among the current biological models,three-dimensional(3D)organoids have developed as powerful tools in the study of nanomaterial-biology(nano-bio)interactions,since these models can overcome many of the limitations of cell and animal models.A deep understanding of organoid techniques will facilitate the development of more efficient nanomedicines and further the fields of tissue engineering and personalized medicine.Herein,we summarize the recent progress in intestinal organoids culture systems with a focus on our understanding of the nature and influencing factors of intestinal organoid growth.We also discuss biomimetic extracellular matrices(ECMs)coupled with nanotechnology.In particular,we analyze the application prospects for intestinal organoids in investigating nano-intestine interactions.By integrating nanotechnology and organoid technology,this recently developed model will fill the gaps left due to the deficiencies of traditional cell and animal models,thus accelerating both our understanding of intestine-related nanotoxicity and the development of nanomedicines.