Topics in Current Chemistry最新文献

The use of magnetic nanoparticles (MNPs), such as iron oxide nanoparticles (IONPs), in biomedicine is considered to be a valuable alternative to the more traditional materials due to their chemical stability, cost-effectiveness, surface functionalization, and the possibility to selectively attach and transport targeted species to the desired location under a magnetic field. One of the many main applications of MNPs is DNA separation, which enables genetic material manipulation; consequently, MNPs are used in numerous biotechnological methods, such as gene transfection and molecular recognition systems. In addition, the interaction between the surfaces of MNPs and DNA molecules and the magnetic nature of the resulting composite have facilitated the development of safe and effective gene delivery vectors to treat significant diseases, such as cancer and neurological disorders. Furthermore, the special recognition properties of nucleic acids based on the binding capacity of DNA and the magnetic behavior of the nanoparticles allowing magnetic separation and concentration of analytes have led to the development of biosensors and diagnostic assays; however, both of these applications face important challenges in terms of the improvement of selective nanocarriers and biosensing capacity. In this review, we discuss some aspects of the properties and surface functionalization of MNPs, the interactions between DNA and IONPs, the preparation of DNA nanoplatforms and their biotechnological applications, such as the magnetic separation of DNA, magnetofection, preparation of DNA vaccines, and molecular recognition tools.

The dramatic increase in atmospheric carbon dioxide (CO₂) concentrations has attracted human attention and many strategies about converting CO₂ into high-value chemicals have been put forward. Metal–organic frameworks (MOFs), as a class of versatile materials, have been widely used in CO₂ capture and chemical conversion, due to their unique porosity, multiple active centers and good stability and recyclability. Herein, we focused on the processes of chemical conversion of CO₂ by MOFs-based catalysts, including the coupling reactions of epoxides, aziridines or alkyne molecules, CO₂ hydrogenation, and other CO₂ conversion reactions. The synthesized methods and high catalytic activity of MOFs-based materials were also analyzed systematically. Finally, a brief perspective on feasible strategies is presented to improve the catalytic activity of novel MOFs-based materials and explore the new CO₂ conversion reactions.

Single-nucleotide variants (SNVs) that are strongly associated with many genetic diseases and tumors are important both biologically and clinically. Detection of SNVs holds great potential for disease diagnosis and prognosis. Recent advances in DNA nanotechnology have offered numerous principles and strategies amenable to the detection and quantification of SNVs with high sensitivity, specificity, and programmability. In this review, we will focus our discussion on emerging techniques making use of DNA strand displacement, a basic building block in dynamic DNA nanotechnology. Based on their operation principles, we classify current SNV detection methods into three main categories, including strategies using toehold-mediated strand displacement reactions, toehold-exchange reactions, and enzyme-mediated strand displacement reactions. These detection methods discriminate SNVs from their wild-type counterparts through subtle differences in thermodynamics, kinetics, or response to enzymatic manipulation. The remarkable programmability of dynamic DNA nanotechnology also allows the predictable design and flexible operation of diverse strand displacement probes and/or primers. Here, we offer a systematic survey of current strategies, with an emphasis on the molecular mechanisms and their applicability to in vitro diagnostics.

Asymmetric metal/organo relay catalysis, utilizing a metal complex and a chiral organocatalyst in a one-pot cascade reaction, is aimed to sequentially impart activation on multiple steps by distinct catalysts. Such a catalysis merges the advantages of both metal catalysis and organocatalysis, providing step-economy, and, more importantly, the potential to achieve inaccessible reactivity by a single catalyst. Chiral phosphoric acids are among the most robust organocatalysts, rendering a broad range of enantioselective bond-forming reactions. The combination of metal complexes and chiral phosphoric acids in a single vessel has been well documented. In particular, the asymmetric relay catalysis of metal complex with chiral phosphoric acid has grown rapidly since 2008. Several excellent reviews have been published to cover almost all examples in this area from 2008 to early 2014; therefore, in this chapter, we will mainly highlight progress from 2014 to mid-2019.

Heterogeneous photocatalysis (HPC) has been widely investigated in recent decades for the removal of a number of contaminants from aqueous matrices, but its application in real wastewater treatment at full scale is still scarce. Indeed, process and technological limitations have made HPC uncompetitive with respect to consolidated processes/technologies so far. In this manuscript, these issues are critically discussed and reviewed with the aim of providing the reader with a realistic picture of the prospective application of HPC in wastewater treatment. Accordingly, consolidated and new photocatalysts (among which the visible active ones are attracting increasing interest among the scientific community), along with preparation methods, are reviewed to understand whether, with increased process efficiency, these methods can be realistically and competitively developed at industrial scale. Precipitation is considered as an attractive method for photocatalyst preparation at the industrial scale; sol–gel and ultrasound may be feasible only if no expensive metal precursor is used, while hydrothermal and solution combustion synthesis are expected to be difficult (expensive) to scale up. The application of HPC in urban and industrial wastewater treatment and possible energy recovery by hydrogen production are discussed in terms of current limitations and future prospects. Despite the fact that HPC has been studied for the removal of pollutants in aqueous matrices for two decades, its use in wastewater treatment is still at a “technological research” stage. In order to accelerate the adoption of HPC at full scale, it is advisable to focus on investigations under real conditions and on developing/improving pilot-scale reactors to better investigate scale-up conditions and the potential to successfully address specific challenges in wastewater treatment through HPC. In realistic terms, the prospective use of HPC is more likely as a tertiary treatment of wastewater, particularly if more stringent regulations come into force, than as pretreatment for industrial wastewater to improve biodegradability.

Plasmonic nanoparticles (NPs) are one of the most promising and studied inorganic nanomaterials for different biomedical applications. Plasmonic NPs have excellent biocompatibility, long-term stability against physical and chemical degradation, relevant optical properties, well-known synthesis methods and tuneable surface functionalities. Herein, we?review recently reported bioconjugated plasmonic NPs using different chemical approaches and loading cargoes (such as drugs, genes, and proteins) for enhancement of transdermal delivery across biological tissues. The main aim is to understand the interaction of the complex skin structure with biomimetic plasmonic NPs. This knowledge is not only important in enhancing transdermal delivery of pharmaceutical formulations but also for controlling undesired skin penetration of industrial products, such as cosmetics, sunscreen formulations and any other mass-usage consumable that contains plasmonic?NPs.

Ferrites are a large class of oxides containing Fe³⁺ and at least another metal cation that have been investigated for and applied to a wide variety of fields ranging from mature technologies like circuitry, permanent magnets, magnetic recording and microwave devices to the most recent developments in areas like bioimaging, gas sensing and photocatalysis. In the last respect, although ferrites have been less studied than other types of semiconductors, they present interesting properties such as visible light absorption, tuneable optoelectronic properties and high chemical and photochemical stability. The versatility of their chemical composition and of their crystallographic structure opened a playground for developing new catalysts with enhanced efficiency. This article reviews the recent development of the application of ferrites to photoassisted processes for environmental remediation and for the synthesis of solar fuels. Applications in the photocatalytic degradation of pollutants in water and air, photo-Fenton, and solar fuels production, via photocatalytic and photoelectrochemical water splitting and CO₂ reduction, are reviewed paying special attention to the relationships between the physico-chemical characteristics of the ferrite materials and their photoactivated performance.

Over the past two decades, metal–organic frameworks (MOFs) with flexible structures or dynamic behavior have shown great potential as functional materials in many fields. This paper presents a review of these dynamic and functional MOFs, which can undergo controllable and reversible transformation, with regard to their application as smart switches. Trigger conditions, which include physical/chemical stimuli (e.g., guest molecules, light, temperature, pressure), are also discussed. Research methods for investigating the dynamic processes and mechanisms involving experimental characterization and computational modeling are briefly mentioned as well. The emphasis is on the aspects of the design and functionalization of dynamic MOFs. The pre-design of metal nodes, organic linkers, and topology, as well as post-modification of components, increases the possibility of obtaining functionalized dynamic materials. Recent advances with regard to potential applications for dynamic frameworks as smart switches for adsorption and sensing are also reviewed.

Interpenetration in metal–organic frameworks (MOFs) can have significant impacts on the structure, porous nature, and functional applications of MOFs. Considered to be disadvantageous in the initial phases leading to a decrease in surface area, interpenetration has proved to be highly useful for modulation of pore size and selective separation of gases. The importance of interpenetration has been realized over the last decade, and numerous approaches to graft interpenetration and utilize it for improved functions and applications have been achieved. Several factors such astemperature, solvent system, time duration and steric aspects of the ligands have been utilized to regulate the degree of interpenetration (DOI). In this review, we summarize recent advances in regulating the DOI in MOFs and its impact on the resulting properties.

Waste-derived materials have been gaining increased attention in recent years due to their great potential and environmentally friendly nature. Several contributions in the literature have covered the advances achieved so far in this area. Nonetheless, to the best of our knowledge, no review has been dedicated specifically to waste-derived or templated photocatalytic materials. Both photocatalysis and (bio)waste-inspired design yield materials of a remarkably green nature. Therefore, the partnership between them may open promising possibilities for both waste valorization and photocatalytic processes, which in turn will lead to sustainable development globally, with the potential for full utilization of renewable energy sources such as biomass and sunlight. Several photocatalytic waste-derived materials, synthetic procedures, and applications will be described throughout this work, including waste-derived/templated TiO₂, ZnO, and metal sulfide materials. Special attention will be given to biomass-inspired carbonaceous materials, including carbon quantum dots and graphitic carbon nitride (g-C₃N₄).