Photothermal enhanced fluorescence quenching of Tb-norfloxacin for ultrasensitive human epididymal 4 detection

Advances in MXene-based luminescence sensing strategies

MXenes have attracted the attention of many researchers as one of the latest two-dimensional (2D) materials over the last decade. Their great potential for biosensing has also been fully exploited after the discovery of their unique properties such as superior optical properties, excellent hydrophilicity, good thermal stability, excellent mechanical property, high electrical conductivity, biocompatibility, large surface area, and ease of surface functionalization. In the MXene-based luminescence sensing strategy, MXenes typically appear in the form of nanosheets, quantum dots and modified MXene nanocomposites, and they are utilized as different sensing platforms or as a luminescence source. In this review, we focused on the MXene-based luminescence sensing strategies, including fluorescence, electrochemiluminescence and chemiluminescence sensors and the comparison of their performance. Finally, the perspectives of the MXene-based luminescence sensors are discussed.

Recent advances using MXenes in biomedical applications

An MXene is a novel two-dimensional transition metal carbide or nitride, with a typical formula of Mn+1XnTx (M = transition metals, X = carbon or nitrogen, and T = functional groups). MXenes have found wide application in biomedicine and biosensing, owing to their high biocompatibility, abundant reactive surface groups, good conductivity, and photothermal properties. Applications include photo- and electrochemical sensors, energy storage, and electronics. This review will highlight recent applications of MXene and MXene-derived materials in drug delivery, tissue engineering, antimicrobial activity, and biosensors (optical and electrochemical). We further elaborate on recent developments in utilizing MXenes for photothermal cancer therapy, and we explore multimodal treatments, including the integration of chemotherapeutic agents or magnetic nanoparticles for enhanced therapeutic efficacy. The high surface area and reactivity of MXenes provide an interface to respond to the changes in the environment, allowing MXene-based drug carriers to respond to changes in pH, reactive oxygen species (ROS), and electrical signals for controlled release applications. Furthermore, the conductivity of MXene enables it to provide electrical stimulation for cultured cells and endows it with photocatalytic capabilities that can be used in antibiotic applications. Wearable and in situ sensors incorporating MXenes are also included. Major challenges and future development directions of MXenes in biomedical applications are also discussed. The remarkable properties of MXenes will undoubtedly lead to their increasing use in the applications discussed here, as well as many others.

Electrospun nanofiber-based indicatorpaper sensing platform for fluorescence and visualization detection of norfloxacin

Norfloxacin (NOR) residues in water pose a serious threat to human health via the food chain, necessitating the development of a rapid on-site antibiotic detection technique. In this work, we utilize electrostatic spinning technology that combines polyacrylonitrile (PAN) fibers and adenosine triphosphate (ATP)-rare earth metal Tb3+ complexes (ATP/Tb) to construct a new ternary film-based sensor for sensitive, quick, and convenient field testing of NOR in water. The operating mechanism is that the ternary system produces gradually enhanced bright green fluorescence at increasing concentrations of NOR. The unique fluorescence property of the ternary systems is attributed to the use of ATP, rather than the commonly used adenosine monophosphate (AMP), to coordinate with Tb3+, which avoided the possible fluorescence quenching from competitive water binding. Benefiting from the PAN nanofiber's superior stability, acid, and alkali resistance, and flexibility as support, the ternary system exhibited a good linear response to NOR in a wide dynamic range of 0.04-30 μM at the detection limit of 16 nM. Additionally, the combination of a smartphone color recognition app allows for quick on-scene NOR detection. This film sensing strategy is instructive for the development of smart and portable sensing platforms for real-time detection of analytes such as antibiotics, pesticide residues, and hazardous materials in water bodies.