Fluorescent Probes for the Detection of Bone Metabolism

The skeleton plays a significant role in human health. Comprehensive and non-invasive visualization of the bone is in high demand to detect bone-related diseases. Clinically, conventional imaging techniques continue to face challenges in terms of limited imaging sensitivity, extended acquisition durations, and the inherent presence of ionizing radiation. These factors collectively hinder their capacity to furnish real-time spatial insights into cellular activity. Recently, Numerous innovative imaging methodologies employing diverse types of probes have emerged to enhance the clinical detection of bone. In vivo imaging of bone contribute to continuously detecting bone metabolism and growth, diagnosing bone metastases, visualizing medication delivery to bones. Fluorescent probes in dynamic detection of bone metabolism several inherent advantages. First, Fluorescent probes present lower potential long-term toxicity than radioactive isotope labels. Second, fluorescent dyes used in in vitro imaging are more cost-effective and come in a more compact size. Next, Near-infrared (NIR) dyes have deeper tissue penetration capability and lower tissue autofluorescence. However, bone-imaging fluorescent probes highly depend on phosphonate-related ligands. These ligands have multiple side effects in clinic and long half-live of them also exacerbates clearance concerns. This review aims to conclude and analyse the recently reported fluorescent probes for the precise detection of bone. Firstly, we outline the fundamental design mechanism of bone fluorescent probes and describe diverse bone-targeting moieties, emphasizing the targeting ligands, signal moieties, and functionalities of these probes. Secondly, we discuss the recent promising bone fluorescent probes for the precise and sensitive detection of bone. Finally, we offer our insights on potential future advancements in this field. We anticipate that this review will inspire creative ideas for designing and creating innovative bone-targeting probes, with applications in bone imaging, pharmaceutical screening, and assessing therapeutic outcomes.