Cation-Induced Assembly of Conductive MXene Fibers for Wearable Heater, Wireless Communication, and Stem Cell Differentiation

Insights on updates in sodium alginate/MXenes composites as the designer matrix for various applications: A review

Advancements in two-dimensional materials, particularly MXenes, have spurred the development of innovative composites through their integration with natural polymers such as sodium alginate (SA). Mxenes exhibit a broad specific surface area, excellent electrical conductivity, and an abundance of surface terminations, which can be combined with SA to maximize the synergistic effect of the materials. This article provides a comprehensive review of state-of-the-art techniques in the fabrication of SA/MXene composites, analyzing the resulting structural and functional enhancements with a specific focus on advancing the design of these composites for practical applications. A detailed exploration of SA/MXene composites is provided, highlighting their utility in various sectors, such as wearable electronics, wastewater treatment, biomedical applications, and electromagnetic interference (EMI) shielding. The review identifies the unique advantages conferred by incorporating MXene in these composites, examines the current challenges, and proposes future research directions to understand and optimize these promising materials thoroughly. The remarkable properties of MXenes are emphasized as crucial for advancing the performance of SA-based composites, indicating significant potential for developing high-performance composite materials.

Advancements in Aptamer-Driven DNA Nanostructures for Precision Drug Delivery

DNA nanostructures exhibit versatile geometries and possess sophisticated capabilities not found in other nanomaterials. They serve as customizable nanoplatforms for orchestrating the spatial arrangement of molecular components, such as biomolecules, antibodies, or synthetic nanomaterials. This is achieved by incorporating oligonucleotides into the design of the nanostructure. In the realm of drug delivery to cancer cells, there is a growing interest in active targeting assays to enhance efficacy and selectivity. The active targeting approach involves a "key-lock" mechanism where the carrier, through its ligand, recognizes specific receptors on tumor cells, facilitating the release of drugs. Various DNA nanostructures, including DNA origami, Tetrahedral, nanoflower, cruciform, nanostar, nanocentipede, and nanococklebur, can traverse the lipid layer of the cell membrane, allowing cargo delivery to the nucleus. Aptamers, easily formed in vitro, are recognized for their targeted delivery capabilities due to their high selectivity for specific targets and low immunogenicity. This review provides a comprehensive overview of recent advancements in the formation and modification of aptamer-modified DNA nanostructures within drug delivery systems.

Thermally Conductive MXene

MXene materials, which consist of nitrides, carbides, or carbonitrides of transition metals, possess a distinctive multilayered structure resulting from the specific etching of the "A" layer from MAX phase precursors. This unique structure allows for tunable properties through intercalation and surface modification. Beyond their structural novelty, MXenes exhibit exceptional thermal conductivity, mechanical resilience, and versatile surface functionalization capabilities, rendering them highly versatile for a wide range of applications. They are particularly renowned for their multifaceted utility and are emerging as outstanding candidates in applications requiring robust thermal conductivity. MXenes, when integrated into textile, fiber, and film forms, have gained increasing relevance in fields where efficient heat management is essential. This work provides a comprehensive exploration of MXene materials, delving into their inherent structure and thermal properties. This Perspective places particular emphasis on their crucial role in efficient heat dissipation, which is vital for the development of wearable heaters and related technologies. Engineered compounds such as MXenes have become indispensable for personal and industrial heating applications, and the advancement of wearable electronic devices necessitates heaters with specific properties, including transparency, mechanical reliability, and adaptability. Recent advancements in emergent thermally conductive MXene compounds are discussed in this study, shedding light on their potential contributions across various domains, including wearable heaters and biosensors for healthcare and environmental monitoring. Furthermore, the versatile nature of MXene materials extends to their application in interfacial solar steam generation, representing a breakthrough approach for solar water desalination. This multifaceted utility underscores the vast potential of MXenes in addressing various pressing challenges.

Recent Advances in MXene-Based Fibers: Fabrication, Performance, and Application

Two-dimensional transition metal carbide/nitrides (MXenes) have recently received extensive attention due to their diverse material types and versatile structures, large-scale production, and excellent properties. MXene sheets possess abundant hydrophilic functional groups on their surface, which enable them to be assembled into macroscopic fibers or compounded with other functional materials to produce composite fibers. This review aims to provide a comprehensive analysis of MXene fibers in terms of their fabrication, structure, properties, and recent applications as flexible and wearable electronics. The review will discuss the principles of different methods used to synthesize MXene fibers and analyze the characteristics of the as-synthesized fibers, with a particular focus on the wet spinning method. The fundamental relationships between the microstructure of MXene fibers and their resulting mechanical and electrical properties will be explored. Furthermore, the review will elaborate on the progress made in MXene-based fibers in the rapidly growing field of wearable electronics applications, provide insights into future development of MXene fiber materials and propose solutions to the challenges facing practical applications.

Polycaprolactone-MXene Nanofibrous Scaffolds for Tissue Engineering

New conductive materials for tissue engineering are needed for the development of regenerative strategies for nervous, muscular, and heart tissues. Polycaprolactone (PCL) is used to obtain biocompatible and biodegradable nanofiber scaffolds by electrospinning. MXenes, a large class of biocompatible 2D nanomaterials, can make polymer scaffolds conductive and hydrophilic. However, an understanding of how their physical properties affect potential biomedical applications is still lacking. We immobilized Ti3C2Tx MXene in several layers on the electrospun PCL membranes and used positron annihilation analysis combined with other techniques to elucidate the defect structure and porosity of nanofiber scaffolds. The polymer base was characterized by the presence of nanopores. The MXene surface layers had abundant vacancies at temperatures of 305-355 K, and a voltage resonance at 8 × 104 Hz with the relaxation time of 6.5 × 106 s was found in the 20-355 K temperature interval. The appearance of a long-lived component of the positron lifetime was observed, which was dependent on the annealing temperature. The study of conductivity of the composite scaffolds in a wide temperature range, including its inductive and capacity components, showed the possibility of the use of MXene-coated PCL membranes as conductive biomaterials. The electronic structure of MXene and the defects formed in its layers were correlated with the biological properties of the scaffolds in vitro and in bacterial adhesion tests. Double and triple MXene coatings formed an appropriate environment for cell attachment and proliferation with mild antibacterial effects. A combination of structural, chemical, electrical, and biological properties of the PCL-MXene composite demonstrated its advantage over the existing conductive scaffolds for tissue engineering.

Recent advances and trends in the applications of MXene nanomaterials for tissue engineering and regeneration

MXene, as a new two-dimensional nanomaterial, is endowed with lots of particular properties, such as large surface area, excellent conductivity, biocompatibility, biodegradability, hydrophilicity, antibacterial activity, and so on. In the past few years, MXene nanomaterials have become a rising star in biomedical fields including biological imaging, tumor diagnosis, biosensor, and tissue engineering. In this review, we sum up the recent applications of MXene nanomaterials in the field of tissue engineering and regeneration. First, we briefly introduced the synthesis and surface modification engineering of MXene. Then we focused on the application and development of MXene and MXene-based composites in skin, bone, nerve and heart tissue engineering. Uniquely, we also paid attention to some research on MXene with few achievements at present but might become a new trend in tissue engineering and regeneration in the future. Finally, this paper will also discuss several challenges faced by MXene nanomaterials in the clinical application of tissue engineering.

Design and Thermal Analysis of Flexible Microheaters

With the development of flexible electronics, flexible microheaters have been applied in many areas. Low power consumption and fast response microheaters have attracted much attention. In this work, systematic thermal and mechanical analyses were conducted for a kind of flexible microheater with two different wire structures. The microheater consisted of polyethylene terephthalate (PET) substrate and copper electric wire with graphene thin film as the middle layer. The steady-state average temperature and heating efficiency for the two structures were compared and it was shown that the S-shaped wire structure was better for voltage-controlled microheater other than circular-shaped structure. In addition, the maximum thermal stress for both structures was from the boundary of microheaters, which indicated that not only the wire structure but also the shape of micro heaters should be considered to reduce the damage caused by thermal stress. The influence resulting from the thickness of graphene thin film also has been discussed. In all, the heating efficiency for flexible microheaters can be up to 135 °C/W. With the proposed PID voltage control system, the response time for the designed microheater was less than 10 s. Moreover, a feasible fabrication process flow for these proposed structures combing thermal analysis results in this work can provide some clues for flexible microheaters design and fabrication in other application areas.