MXene is a recently emerged multifaceted two-dimensional (2D) material that is made up of surface-modified carbide, providing its flexibility and variable composition. They consist of layers of early transition metals (M), interleaved with n layers of carbon or nitrogen (denoted as X) and terminated with surface functional groups (denoted as T_x/T_z) with a general formula of M_n+1X_nT_x, where n = 1–3. In general, MXenes possess an exclusive combination of properties, which include, high electrical conductivity, good mechanical stability, and excellent optical properties. MXenes also exhibit good biological properties, with high surface area for drug loading/delivery, good hydrophilicity for biocompatibility, and other electronic-related properties for computed tomography (CT) scans and magnetic resonance imaging (MRI). Due to the attractive physicochemical and biocompatibility properties, the novel 2D materials have enticed an uprising research interest for application in biomedicine and biotechnology. Although some potential applications of MXenes in biomedicine have been explored recently, the types of MXene applied in the perspective of biomedical engineering and biomedicine are limited to a few, titanium carbide and tantalum carbide families of MXenes. This review paper aims to provide an overview of the structural organization of MXenes, different top-down and bottom-up approaches for synthesis of MXenes, whether they are fluorine-based or fluorine-free etching methods to produce biocompatible MXenes. MXenes can be further modified to enhance the biodegradability and reduce the cytotoxicity of the material for biosensing, cancer theranostics, drug delivery and bio-imaging applications. The antimicrobial activity of MXene and the mechanism of MXenes in damaging the cell membrane were also discussed. Some challenges for in vivo applications, pitfalls, and future outlooks for the deployment of MXene in biomedical devices were demystified. Overall, this review puts into perspective the current advancements and prospects of MXenes in realizing this 2D nanomaterial as a versatile biological tool.

Water quality monitoring plays a significant part in the transition towards intelligent and smart agriculture and provides an easy transition to automated monitoring of crucial components of human daily needs as new technologies are continuously developed and adopted in agricultural and human daily life (water). For the monitoring and management of water quality, this effort, however, requires reliable models with accurate and thorough datasets. Analyzing water quality monitoring models by utilizing sensors that gather water properties during live experiments is possible due to the necessity for precision in modeling. To convey numerous conclusions regarding the concerns, issues, difficulties, and research gaps that have existed throughout the past five years (2018–2022), this review article thoroughly examines the water quality literature. To find trustworthy peer-reviewed publications, several digital databases were searched and examined, including IEEE Xplore^®, ScienceDirect, Scopus, and Web of Science. Only 50 articles out of the 946 papers obtained, were used in the study of the water quality monitoring research area. There are more rules for article inclusion in the second stage of the filtration process. Utilizing a real-time data acquisition system, the criteria for inclusion for the second phase of filtration looked at the implementation of water quality monitoring and characterization procedures. Reviews and experimental studies comprised most of the articles, which were divided into three categories. To organize the literature into articles with similar types of experimental conditions, a taxonomy of the three literature was created. Topics for recommendations are also provided to facilitate and speed up the pace of advancement in this field of study. By conducting a thorough analysis of the earlier suggested methodologies, research gaps are made clear. The investigation largely pointed out the problems in the accuracy of the models, the development of data-gathering systems, and the types of data used in the proposed frameworks. Finally, by examining critical topics required for the development of this research area, research directions toward smart water quality are presented.

In the present work, a facile one-step hydrothermal synthesis of well-defined stabilized CuO nanopetals and its surface study by advanced nanocharacterization techniques for enhanced optical and catalytic properties has been investigated. Characterization by Transmission electron microscopy (TEM) analysis confirmed existence of high crystalline CuO nanopetals with average length and diameter of 1611.96 nm and 650.50 nm, respectively. The nanopetals are monodispersed with a large surface area, controlled morphology, and demonstrate the nanocrystalline nature with a monoclinic structure. The phase purity of the as-synthesized sample was confirmed by Raman spectroscopy and X-ray diffraction (XRD) patterns. A significantly wide absorption up to 800 nm and increased band gap were observed in CuO nanopetals. The valance band (VB) and conduction band (CB) positions at CuO surface are measured to be of +0.7 and −1.03 eV, respectively, using X-ray photoelectron spectroscopy (XPS), which would be very promising for efficient catalytic properties. Furthermore, the obtained CuO nanopetals in the presence of hydrogen peroxide ( ${\mathrm{H}}_2{\mathrm{O}}_2)$ achieved excellent catalytic activities for degradation of methylene blue (MB) under dark, with degradation rate > 99% after 90 min, which is significantly higher than reported in the literature. The enhanced catalytic activity was referred to the controlled morphology of monodispersed CuO nanopetals, co-operative role of ${\mathrm{H}}_2{\mathrm{O}}_2$ and energy band structure. This work contributes to a new approach for extensive application opportunities in environmental improvement.