MXenes—A New Class of Two-Dimensional Materials: Structure, Properties and Potential Applications

Abstract

A new class of two-dimensional nanomaterials, MXenes, which are carbides/nitrides/carbonitrides of transition and refractory metals, has been critically analyzed. Since the synthesis of the first family member in 2011 by Yury Gogotsi and colleagues, MXenes have quickly become attractive for a variety of research fields due to their exceptional properties. Despite the fact that this new family of 2D materials was discovered only about ten years ago, the number of scientific publications related to MXene almost doubles every year. Thus, in 2021 alone, more than 2000 papers are expected to be published, which indicates the relevance and prospects of MXenes. The current paper critically analyzes the structural features, properties, and methods of synthesis of MXenes based on recent available research data. We demonstrate the recent trends of MXene applications in various fields, such as environmental pollution removal and water desalination, energy storage and harvesting, quantum dots, sensors, electrodes, and optical devices. We focus on the most important medical applications: photo-thermal cancer therapy, diagnostics, and antibacterial treatment. The first results on obtaining and studying the structure of high-entropy MXenes are also presented.

MXene-Assisted Ablation of Cells with a Pulsed Near-Infrared Laser

“…MXenes of various compositions and structures generally display reasonable biological compatibility . In the present study, the Ti 3 C 2 T x MXene was well tolerated in both normal and cancerous cells in vitro .…”

“…After the exposure, the increased temperature of the MXenes associated with the cells causes direct cell injury with the destruction of membranes and denaturation of proteins that leads to cell death by the necrosis pathway. This mechanism has been proposed by some authors based on in vitro and in vivo experiments . The second mechanism assumes temperature damage from the warmed-up medium: the free-floating MXene flakes cause the temperature of the culture medium to increase and induce temperature-dependent apoptosis .…”

“…This mechanism has been proposed by some authors based on in vitro and in vivo experiments. 43 The second mechanism assumes temperature damage from the warmed-up medium: the free-floating MXene flakes cause the temperature of the culture medium to increase and induce temperature-dependent apoptosis. 64 The elevated temperature of the medium could also cause cell necrosis contributing to cancer cell death.…”

A Review of Advancing Two-Dimensional Material Membranes for Ultrafast and Highly Selective Liquid Separation

“…MXenes, a general term for transition metal carbon/nitrides, are a new class of twodimensional nanomaterials developed in recent years [111]. Due to their high aspect ratio, abundant surface groups, good electrical conductivity, and natural hydrophilicity, they have been widely used in energy storage, catalysis, sensing, and the environment [112,113]. MXenes are regarded as promising candidate materials in the field of membrane separation, and the most widely used MXene is Ti 3 C 2 T x (T = O, F, OH) [114].…”

Advanced MXene-Based Micro- and Nanosystems for Targeted Drug Delivery in Cancer Therapy

“…On the other hand, with the discovery of graphene [ 20 ], transition metal dichalcogenides (e.g., TiS 2 , MoS 2 , and WS 2 ) [ 21 , 22 , 23 ], black phosphorus nanosheets [ 24 ], layered double hydroxides [ 25 ], graphitic carbon nitride [ 26 ], boron nitride [ 27 ], metal–organic frameworks [ 28 ], and transition metal oxides [ 29 ], among others, a variety of advanced micro- and nanosystems have been designed for cancer therapy. Recently, MXenes, 2D material comprising transition metal carbides, nitrides or carbonitrides, have captured widespread attention in photothermal therapy (PTT) in view of the high light-to-heat conversion efficiency, elevated paramagnetic performance, and large specific surface area [ 30 , 31 , 32 ]. However, MXene photothermal agents (PTAs) are unstable in aqueous/oxidative surroundings as their terminal functional groups (–F, –OH, or –O) are vulnerable to oxidation and tend to aggregate in physiological solutions; although, after suitable modification/functionalization, the stability and properties of these structures can be improved [ 33 ].…”