Current Trends in the Optical Characterization of Two-Dimensional Carbon Nanomaterials

Past progress in environmental nanoanalysis and a future trajectory for atomic mass-spectrometry methods

The development of engineered nanotechnology has necessitated a commensurate maturation of nanoanalysis capabilities. Building off a legacy established by electron microscopy and light-scattering, environmental nanoanalysis has now benefited from ongoing advancements in instrumentation and data analysis, which enable a deeper understanding of nanomaterial properties, behavior, and impacts. Where once environmental nanoparticles and colloids were grouped into broad 'dissolved or particulate' classes that are dependent on a filter size cut-off, now size distributions of submicron particles can be separated and characterized providing a more comprehensive examination of the nanoscale. Inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS), directly coupled to field flow fractionation (FFF-ICP-QMS) or operated in single particle mode (spICP-MS) have spearheaded a revolution in nanoanalysis, enabling research into nanomaterial behavior in environmental and biological systems at expected release concentrations. However, the complexity of the nanoparticle population drives a need to characterize and quantify the multi-element composition of nanoparticles, which has begun to be realized through the application of time-of-flight MS (spICP-TOFMS). Despite its relative infancy, this technique has begun to make significant strides in more fully characterizing particulate systems and expanding our understanding of nanoparticle behavior. Though there is still more work to be done with regards to improving instrumentation and data processing, it is possible we are on the cusp of a new nanoanalysis revolution, capable of broadening our understanding of the size regime between dissolved and bulk particulate compartments of the environment.

Advancements in defect engineering of two-dimensional nanomaterial-based membranes for enhanced gas separation

The advent of two-dimensional nanomaterials, a revolutionary class of materials, is marked by their atomic-scale thickness, superior aspect ratios, robust mechanical attributes, and exceptional chemical stability. These materials, producible on a large scale, are emerging as the forefront candidates in the domain of membrane-based gas separation. The concept of defect engineering in 2D nanomaterials has introduced a novel approach in their application for membrane separation, offering an effective technique to augment the performance of these membranes. Nonetheless, the development of customized microstructures in gas separation membranes via defect engineering remains nascent. Hence, this review is designed to serve as a comprehensive guide for the application of defect engineering in 2D nanomaterial-based membranes. It delves into the most recent developments in this field, encompassing the synthesis methodologies of defective 2D nanomaterials and the mechanisms underlying gas transport. Special emphasis is placed on the utilization of defect-engineered 2D nanomaterial-based membranes in gas capture applications. Furthermore, the paper encapsulates the burgeoning challenges and prospective advancements in this area. In essence, defect engineering emerges as a promising avenue for enhancing the efficacy of 2D nanomaterial-based membranes in gas separation, offering significant potential for advancements in membrane-based gas separation technologies.

Carbon Nanomaterial Fluorescent Probes and Their Biological Applications

Fluorescent carbon nanomaterials have broadly useful chemical and photophysical attributes that are conducive to applications in biology. In this review, we focus on materials whose photophysics allow for the use of these materials in biomedical and environmental applications, with emphasis on imaging, biosensing, and cargo delivery. The review focuses primarily on graphitic carbon nanomaterials including graphene and its derivatives, carbon nanotubes, as well as carbon dots and carbon nanohoops. Recent advances in and future prospects of these fields are discussed at depth, and where appropriate, references to reviews pertaining to older literature are provided.

Synergistic anti-inflammatory effects of graphene oxide quantum dots and trans-10-hydroxy-2-decenoic acid on LPS-stimulated RAW 264.7 macrophage cells

Graphene oxide quantum dots (GOQDs) have attracted substantial attention in numerous fields due to their unique physicochemical properties. However, their nanotoxicity and potential for use in biomedicine still require further study. In this work, the effects of GOQD and trans- 10-hydroxy-2-decenoic acid (10-HDA) cotreatment on the immune function of macrophages (RAW264.7 cells) were investigated. In particular, LC/MS-based metabolomics was performed to evaluate the effects of GOQDs on the metabolism of LPS-stimulated macrophages. Herein, we fabricated GOQDs with good dispersibility and a uniform size distribution of approximately 7 nm using a polyimide-pyrolyzed carbon film as the working electrode, a high-voltage graphite electrode as the cathode, and H₂O₂ as the oxidant. The GOQDs entered the macrophages and emitted green fluorescence under UV irradiation. Cotreatment with GOQDs and 10-HDA induced RAW 264.7 cell proliferation. GOQDs promoted the anti-inflammatory effect of 10-HDA on LPS-stimulated RAW264.7 cells and attenuated the secretion of TNF-α, IL-6, and IL-1β. The metabolites in RAW264.7 cells treated with GOQDs were significantly different from those in RAW264.7 cells treated with LPS. The enrichment analysis showed that treatment with GOQDs interfered with amino acid metabolism, and lipid metabolism. Our results demonstrate the role of GOQDs in macrophages and provide a basis for their further application in biomedical fields.

Recent trends in covalent functionalization of 2D materials

Covalent functionalization of the surface is more crucial in 2D materials than in conventional bulk materials because of their atomic thinness, large surface-to-volume ratio, and uniform surface chemical potential. Because...