MXenes are a class of 2D transition-metal carbides, nitrides, and carbonitrides with exceptional properties, including substantial electrical and thermal conductivities, outstanding mechanical strength, and a considerable surface area, rendering them an appealing choice for gas sensors. This manuscript provides a comprehensive analysis of heterostructures based on MXenes employed in gas-sensing applications and focuses on addressing the limited understanding of the sensor mechanisms of MXene-based heterostructures while highlighting their potential to enhance gas-sensing performance. The manuscript begins with a broad overview of gas-sensing mechanisms in both pristine materials and MXene-based heterostructures. Subsequently, it explores various features of MXene-based heterostructures, including their composites with other materials and their prospects for gas-sensing applications. Additionally, the manuscript evaluates different engineering strategies for MXenes and compares their advantages to other materials while discussing the limitations of current state-of-the-art sensors. Ultimately, this review seeks to foster collaboration and knowledge exchange within the field, facilitating the development of high-performance gas sensors based on MXenes.

This work reports the fabrication of monodisperse nickel–cobalt phosphate particles with varying structures via the solvothermal reaction of nickel–cobalt glycerate spheres with triethyl phosphate (TEP) in different solvents followed by subsequent calcination in air at 600 °C. The choice of solvent affects the morphology of the resulting nickel–cobalt phosphate precursor obtained from the solvothermal reaction. It is found that alcohol-based solvents (pure ethanol and ethanol/butanol mixture) favour the formation of monodisperse plate-like particles, while the use of a water/ethanol mixture promotes the generation of rod-like particles. The optimized amorphous nickel–cobalt phosphate sample prepared using pure ethanol followed by calcination in air at 600 °C (E-NiCo-TEP-600) exhibits a battery-like behaviour with a high specific capacity of 620 C g⁻¹ (specific capacitance of 1550 F g⁻¹) in 6.0 M KOH at a current density of 2 A g⁻¹. Furthermore, the asymmetric supercapacitor (ASC) fabricated using E-NiCo-TEP-600 as the cathode and commercial activated carbon (AC) as the anode (E-NiCo-TEP-600//AC ASC) displays a maximum energy density of 45 W h kg⁻¹ at a power density of 750 W kg⁻¹. The stability test reveals the good long-term stability of this ASC with a high capacitance retention of ∼100% after 5000 cycles at a high current density of 10 A g⁻¹. The porous nature along with the high structural disorder and abundant mesopores in the amorphous nickel-cobalt phosphate plate-like particles (E-NiCo-TEP-600) can promote faster diffusion of electrolyte ions and better electrolyte ion penetration, leading to a higher electrochemical performance. These results indicate the promising potential of porous amorphous bimetallic phosphates for supercapacitors.

In this study, multifunctional chitosan-pluronic F127 with magnetic reduced graphene oxide (MRGO) nanocomposites were developed through the immobilization of chitosan and an amphiphilic polymer (pluronic F127) onto the MRGO. Physicochemical characterizations and in-vitro cytotoxicity of nanocomposites were investigated through field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, particle size analysis, vibrating sample magnetometer, Raman spectroscopy and resazurin-based in-vitro cytotoxicity assay. FESEM observation shows that the magnetic nanoparticles could tethered on the surface of MRGO, promoting the magnetic properties of the nanocomposites. FTIR identification analysis revealed that the chitosan/pluronic F127 were successfully immobilized on the surface of MRGO. Furthermore, α-mangosteen, as a model of natural drug compound, was successfully encapsulated onto the chitosan/pluronic F127@MRGO nanocomposites. According to in-vitro cytotoxicity assay, α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could significantly reduce the proliferation of human breast cancer (MFC-7) cells. Eventually, it would be anticipated that the novel α-mangosteen-loaded chitosan/pluronic F127@MRGO nanocomposites could be promoted as a new potential material for magnetically targeting and killing cancer cells.

Pandemics such as COVID-19 have highlighted the importance of point-of-care sensors for testing, tracing, and treatment to minimize and manage infection. Biosensors have been widely deployed in portable devices such as glucose sensors and pregnancy tests. Their development for point-of-exposure virus detection or point-of-care devices is anticipated but their reliability for the accurate detection of viruses is critical. Nanomaterials, such as metal nanoparticles (NPs), magnetic NPs, quantum dots, carbon-based nanomaterials, and molecularly imprinted polymer (MIP) NPs, have been utilized in biosensors to enhance sensitivity. Molecular imprinting is a cost-effective method to synthesize polymers for selective binding, which have excellent properties as biosensors. More research on MIP NPs can be expected in the near future. The utilization of nanomaterials in several types of transducers for biosensor devices is also illustrated to give an overview of their use. Finally, a summary is given together with a future perspective on how biosensors can be further developed as reliable, portable viral biosensors.