Fluorescent probes, typically based on the intramolecular charge transfer (ICT) mechanism, have received considerable research attention in cell detection due to their non-invasiveness, fast response, easy regulation, high sensitivity, and low damage tolerance for in vivo bio-samples. Generally, intracellular pH and biological species such as various gases, metal ions, and anions constitute the foundation of cells and participate in the basic physiological processes, whose abnormal level can lead to poisoning, cardiovascular disease, and cancer in living organisms. Therefore, monitoring of their quantity plays an essential role in understanding the status of organisms and preventing, diagnosing, and treating diseases. In the last decades, remarkable progress has been made in developing ICT probes for the detection of biological elements. In this review, we highlight the recent ICT probes focusing primarily on the detection of intracellular pH, various gases (H₂S, CO, H₂O₂, and NO), metal ions (Cu²⁺, Hg²⁺, Pb²⁺, Zn²⁺, and Al³⁺), and anions (ClO⁻, CN⁻, SO₃²⁻, and F⁻). In addition, we discuss the issues and limitations of ICT-based fluorescent probes for in vivo detection and explore the clinical translational potential and challenges of these materials, providing valuable guidance and insights for the design of fluorescent materials.

Well-designed artificial scaffolds are urgently needed due to the limited self-repair capacity of bone, which hampers effective regeneration in critical defects. Optimal scaffolds must provide physical guidance to recruit cells and immune regulation to improve the regenerative microenvironment. This study presents a novel scaffold composed of dual-sided centripetal microgrooved poly(D,L-lactide-co-caprolactone) (PLCL) film combined with a dynamic hydrogel containing prednisolone (PLS)-loaded Prussian blue nanoparticles (PB@PLS). The microgrooves on the surface of the PLCL film were imprinted using a micropatterned polydimethylsiloxane (PDMS) template. Following aminolysis, the PLCL film was covalently grafted with the EM-7 peptide via glutaraldehyde. Functional group analysis, surface morphology and hydrophilicity were evaluated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and an optical contact angle measuring instrument, respectively. Bone regeneration-related cells (e.g., bone marrow mesenchymal stem cells, macrophages, Schwann cells, and endothelial cells) cultured on PLCL films tended to align along the stripes and migrate from the periphery toward the center region in vitro. Subsequently, the PLCL film was encapsulated in an immune-regulating hydrogel synthesized from thiol-modified gelatin and Cu²⁺ in the presence of PB@PLS nanoparticles, which demonstrated excellent antioxidant properties. This scaffold significantly accelerated critical-sized bone regeneration, as evidenced by an increase in the volume of newly formed bone and histological images in vivo. This innovative approach holds substantial promise for clinical applications in bone regeneration and broader tissue repair.

Alzheimer’s disease (AD) is a neurodegenerative disease. Due to its complex pathological mechanism, its etiology is not yet clear. As one of the main pathological markers of AD, amyloid-β (Aβ) plays an important role in the development of AD. The deposition of Aβ is not only related to the degeneration of neurons, but also can activate a series of pathological events, including the activation of astrocytes and microglia, the breakdown of the blood–brain barrier, and the change in microcirculation, which is the main cause of brain lesions and death in AD patients. Therefore, the development of efficient and reliable Aβ-specific probes is crucial for the early diagnosis and treatment of AD. This paper focuses on reviewing the application of small-molecule fluorescent probes in Aβ imaging in vivo in recent years. These probes efficiently map the presence of Aβ in vivo, providing a pathway for the early diagnosis of AD and providing enlightenment for the design of Aβ-specific probes in the future.

Fluorescent materials have great potential for use in biomedical applications due to their ease of functionalization and tunable fluorescence color

Severe traction injuries after stretch to peripheral nerves are common and challenging to repair. The nerve guidance conduits (NGCs) are promising in the regeneration and functional recovery after nerve injuries. To enhance the repair of severe nerve traction injuries, in this study KHIFSDDSSE (KHI) peptides were grafted on a porous and micropatterned poly(D,L-lactide-co-caprolactone) (PLCL) film (MPLCL), which was further loaded with a nerve growth factor (NGF). The adhesion number of Schwann cells (SCs), ratio of length/width (L/W), and percentage of elongated SCs were significantly higher in the MPLCL-peptide group and MPLCL-peptide-NGF group compared with those in the PLCL group in vitro. The electromyography (EMG) and morphological changes of the nerve after severe traction injury were improved significantly in the MPLCL-peptide group and MPLCL-peptide-NGF group compared with those in the PLCL group in vivo. Hence, the NGCs featured with both bioactive factors (KHI peptides and NGF) and physical topography (parallelly linear micropatterns) have synergistic effect on nerve reinnervation after severe traction injuries.