Measuring anion binding at biomembrane interfaces

Understanding non-covalent molecular recognition events at biomembrane interfaces is important in biological, medicinal, and materials chemistry research.1 Despite the crucial regulatory roles of anion binding/transport processes at biomembranes, no information is available regarding how strongly anions can bind to naturally occurring or synthetic receptors in lipid bilayer environments compared to their well-established behaviour in solutions.2 To bridge this knowledge gap, we synthesised a flat macrocycle that possesses a record aqueous SO42– affinity among neutral receptors and exploited its unique fluorescence response at interfaces. We show that the determinants of anion binding are extraordinarily different in organic solvents and in lipid bilayers. The high charge density of dihydrogen phosphate and chloride ions prevails in DMSO, however in lipids they fail to bind the macrocycle. Perchlorate and iodide hardly bind in DMSO but show significant affinities for the macrocycle in lipids. Our results demonstrate a surprisingly great advantage of large, charge-diffuse anions to bind to a lipid-embedded synthetic receptor mainly attributed to their higher polarisabilities and deeper penetration into the bilayer, beyond the common knowledge of dehydration energy-governed selectivity. The elucidation of these principles enhances our understanding of biological anion recognition functions in membranes and guides the design of ionophores and molecular machines operating at biomembrane interfaces.

Induction and application of ferroptosis in cancer therapy

At present, more than one cell death pathways have been found, one of which is ferroptosis. Ferroptosis was discovered in 2012 and described as an iron-dependent and lipid peroxidation-driven regulated cell death pathway. In the past few years, ferroptosis has been shown to induce tumor cell death, providing new ideas for tumor treatment. In this article, we summarize the latest advances in ferroptosis-induced tumor therapy at the intersection of tumor biology, molecular biology, redox biology, and materials chemistry. First, we state the characteristics of ferroptosis in cells, then introduce the key molecular mechanism of ferroptosis, and describes the relationship between ferroptosis and oxidative stress signaling pathways. Finally, we focused on several types of ferroptosis inducers discovered by scholars, and the application of ferroptosis in systemic chemotherapy, radiotherapy, immunotherapy and nanomedicine, in the hope that ferroptosis can exert its potential in the treatment of tumors.

Introduction to materials chemistry at Xi’an Jiaotong University

Dongfeng Dang, Yanfeng Zhang, Shujiang Ding and Zhicheng Zhang introduce the Materials Chemistry Frontiers themed collection on materials chemistry research at Xi’an Jiaotong University.

Preface

The International Conference on Materials Chemistry and Environmental Engineering (CONF-MCEE 2021) The International Conference on Materials Chemistry and Environmental Engineering (CONF-MCEE 2021) is a leading conference, hosted by Eliwise Academy annually. It encourages communication and collaboration, hoping to provide an international platform for its participants to present, share, and learn the latest advance and development of materials, chemistry, and environmental engineering. Academics, researchers, and students from across the world are all welcomed to exchange findings and ideas to draw further inspirations in these research fields. It’s a great opportunity to deepen your understanding in the related topics. This volume contains the papers presented at the International Conference on Materials Chemistry and Environmental Engineering (CONF-MCEE 2021), held during November 11-16, 2021. Under the influence of COVID-19, the on-site conference was regretfully cancelled and CONF-MCEE was held online. For the safety concern of all participants, we decided to hold a virtual conference which is also effective and convenient for academic exchange and communication. Everyone interested in this field were welcomed to join the online conference on our YouTube channel and to give comments and raise questions to the speeches and presentations. We are hoping the pandemic to soon come to an end and we could see each other next year. CONF-MCEE 2021 received 179 submissions in the area of materials science and engineering, chemical science and technology, and environmental engineering. Each of the 179 submissions was reviewed by at least two Program Committee members. The committee decided to accept 64 papers that are included in these proceedings. We would like to thank the Program Committee members and external reviewers for their hard work in reviewing and selecting papers. Hopefully, all participants and other interested readers can benefit scientifically from the proceedings and find it rewarding in the process. Prof. Shuai Chen Chairman of Conference Committee List of Committee, Chairman, Technical Program Committee, Organizing Committee, Publicity Committee are available in this pdf.

Measuring anion binding at biomembrane interfaces

Understanding non-covalent molecular recognition events at biomembrane interfaces is important in biological, medicinal, and materials chemistry research.1 Despite the crucial regulatory roles of anion binding/transport processes at biomembranes, no information is available regarding how strongly anions can bind to naturally occurring or synthetic receptors in lipid bilayer environments compared to their well-established behaviour in solutions.2 To bridge this knowledge gap, we synthesised a flat macrocycle that possesses a record aqueous SO42– affinity among neutral receptors and exploited its unique fluorescence response at interfaces. We show that the determinants of anion binding are extraordinarily different in organic solvents and in lipid bilayers. The high charge density of dihydrogen phosphate and chloride ions prevails in DMSO, however in lipids they fail to bind the macrocycle. Perchlorate and iodide hardly bind in DMSO but show significant affinities for the macrocycle in lipids. Our results demonstrate a surprisingly great advantage of large, charge-diffuse anions to bind to a lipid-embedded synthetic receptor mainly attributed to their higher polarisabilities and deeper penetration into the bilayer, beyond the common knowledge of dehydration energy-governed selectivity. The elucidation of these principles enhances our understanding of biological anion recognition functions in membranes and guides the design of ionophores and molecular machines operating at biomembrane interfaces.

Measuring anion binding at biomembrane interfaces

Understanding non-covalent molecular recognition events at biomembrane interfaces is important in biological, medicinal, and materials chemistry research.1 Despite the crucial regulatory roles of anion binding/transport processes at biomembranes, no information is available regarding how strongly anions can bind to naturally occurring or synthetic receptors in lipid bilayer environments compared to their well-established behaviour in solutions.2 To bridge this knowledge gap, we synthesised a flat macrocycle that possesses a record aqueous SO42– affinity among neutral receptors and exploited its unique fluorescence response at interfaces. We show that the determinants of anion binding are extraordinarily different in organic solvents and in lipid bilayers. The high charge density of dihydrogen phosphate and chloride ions prevails in DMSO, however in lipids they fail to bind the macrocycle. Perchlorate and iodide hardly bind in DMSO but show significant affinities for the macrocycle in lipids. Our results demonstrate a surprisingly great advantage of large, charge-diffuse anions to bind to a lipid-embedded synthetic receptor mainly attributed to their higher polarisabilities and deeper penetration into the bilayer, beyond the common knowledge of dehydration energy-governed selectivity. The elucidation of these principles enhances our understanding of biological anion recognition functions in membranes and guides the design of ionophores and molecular machines operating at biomembrane interfaces.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric photoluminescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4-dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric fluorescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric, enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4- dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

Ir-catalyzed enantioselective B−H alkenylation for asymmetric synthesis of chiral-at-cage o‑carboranes

The asymmetric synthesis of chiral-at-cage o-carboranes, whose chirality is associated with the substitution patterns on the polyhedron, is of great interest as the icosahedral carboranes have wide applications in medicinal and materials chemistry. Herein we report an intermolecular Ir-catalyzed enantioselective B−H alkenylation for efficient and facile synthesis of chiral-at-cage o-carboranes with new skeletons under mild reaction conditions. Generally very good to excellent yields with up to 99% ee can be achieved in this Ir-catalyzed B−H alkenylation. The enantiocontrol model is proposed based on Density Functional Theory calculations in which the use of chiral phosphoramidite ligand is essential for such asymmetric o-carborane B−H alkenylation.

Reviewing the Safe Shipping of Lithium-Ion and Sodium-Ion Cells: A Materials Chemistry Perspective

High energy density lithium-ion (Li-ion) batteries are commonly used nowadays. Three decades’ worth of intense research has led to a good understanding on several aspects of such batteries. But, the issue of their safe storage and transportation is still not widely understood from a materials chemistry perspective. Current international regulations require Li-ion cells to be shipped at 30% SOC (State of Charge) or lower. In this article, the reasons behind this requirement for shipping Li-ion batteries are firstly reviewed and then compared with those of the analogous and recently commercialized sodium-ion (Na-ion) batteries. For such alkali-ion batteries, the safest state from their active materials viewpoint is at 0 V or zero energy, and this should be their ideal state for storage/shipping. However, a “fully discharged” Li-ion cell used most commonly, composed of graphite-based anode on copper current collector, is not actually at 0 V at its rated 0% SOC, contrary to what one might expect—the detailed mechanism behind the reason for this, namely, copper dissolution, and how it negatively affects cycling performance and cell safety, will be summarized herein. It will be shown that Na-ion cells, capable of using a lighter and cheaper aluminum current collector on the anode, can actually be safely discharged to 0 V (true 0% SOC) and beyond, even to reverse polarity (negative voltages). It is anticipated that this article spurs further research on the 0 V capability of Na-ion systems, with some suggestions for future studies provided.