The ultrafine biosensing technology reveals the mechanisms of various biochemical reactions in cells and the causes of complex diseases through the detection of cellular and subcellular structures. It has an irreplaceable role in the early diagnosis of diseases and in the evaluation of the effectiveness of drug therapy. Due to the complex media composition and ultrafine size of biological cells, traditional sensing technologies can hardly shoulder this difficult task. Nanodiamond (ND) is chemically inert, biocompatible, and nanoscale in size; therefore, it is a safe, non-invasive tool for intracellular sensing. In this Review, we will present the properties of nitrogen vacancy centers, silicon vacancy centers in ND, functionalization of ND, and brief principles of sensing, as well as the latest applications, opportunities, and challenges of ND biosensing.

Nanodiamonds (NDs) are emerging as a promising candidate for multimodal bioimaging on account of their optical and spectroscopic properties. NDs are extensively utilized for bioimaging probes due to their defects and admixtures in their crystal lattice. There are many optically active defects presented in NDs called color centers, which are highly photostable, extremely sensitive to bioimaging, and capable of electron leap in the forbidden band; further, they absorb or emit light when leaping, enabling the nanodiamond to fluoresce. Fluorescent imaging plays a significant role in bioscience research, but traditional fluorescent dyes have some drawbacks in physical, optical and toxicity aspects. As a novel fluorescent labeling tool, NDs have become the focus of research in the field of biomarkers in recent years because of their various irreplaceable advantages. This review primarily focuses on the recent application progress of nanodiamonds in the field of bioimaging. In this paper, we will summarize the progress of ND research from the following aspects (including fluorescence imaging, Raman imaging, X-ray imaging, magnetic modulation fluorescence imaging, magnetic resonance imaging, cathodoluminescence imaging, and optical coherence tomography imaging) and expect to supply an outlook contribution for future nanodiamond exploration in bioimaging.

Transition metal phosphides exhibit diverse crystal structures and intriguing physical properties, including superconductivity and magnetism. Despite extensive studies, obtaining a comprehensive understanding of the synthesis methods, structural variations, and emergent phenomena in binary and ternary phosphides remains an essential task. Here, we review recent progress in the synthesis, crystal structures, and physical properties of binary (e.g., Mo–P, Rh–P, Re–P, and Ir–P) and ternary (transition metal–transition metal–phosphorus, alkaline earth metal–transition metal–phosphorus, and rare earth element–transition metal–phosphorus) phosphides. Emphasis is placed on superconductivity, magnetism, and electronic structures, highlighting correlations between composition, structure, and properties. This synthesis of current knowledge provides insights into the design of novel phosphide materials and can guide future exploration of functional materials with tailored electronic and magnetic behaviors.