Recent advances in sugar-based AIE luminogens and their applications in sensing and imaging

Most fluorogens with aggregation-induced emission (AIE) characteristics are hydrophobic and most common sugars are hydrophilic and naturally nontoxic. The combination of AIEgens and sugars can construct glycosyl AIEgens with the advantages of good water-solubility, low fluorescent background and satisfactory biocompatibility. Based on the specific reaction or binding with analytes to change the conjugate system or restrict intramolecular motions, glycosyl AIEgens can be used as powerful tools for detecting bioactive molecules or imaging living cells. In this feature article, we summarize recent advances in sugar-based AIE luminogens and their applications in biosensing and imaging. The sugar units could significantly increase the solubility, biocompatibility, target activity, and chemical modifying capacity and often decrease the background fluorescence of the AIE probes. Corresponding studies not only expand the application fields of AIEgens but also provide effective tools for broad carbohydrate research.

Multivalent glycosystems for human lectins

Human lectins are involved in a wide variety of biological processes, both physiological and pathological, which have attracted the interest of the scientific community working in the glycoscience field. Multivalent glycosystems have been employed as useful tools to understand carbohydrate-lectin binding processes as well as for biomedical applications. The review shows the different scaffolds designed for a multivalent presentation of sugars and their corresponding binding studies to lectins and in some cases, their biological activities. We summarise this research by organizing based on lectin types to highlight the progression in this active field. The paper provides an overall picture of how these contributions have furnished relevant information on this topic to help in understanding and participate in these carbohydrate-lectin interactions.

Sialylated IgG in epithelial cancers inhibits antitumor function of T cells via Siglec-7

Although effective, immune checkpoint blockade induces response in only a subset of cancer patients. There is an urgent need to discover new immune checkpoint targets. Recently, it was found that a class of sialic acid-binding immunoglobulin-like lectins (Siglecs) expressed on the surface of T cells in cancer patients inhibit T cell activation through their intracellular immunosuppressive motifs by recognizing sialic acid-carrying glycans, sialoglycans. However, ligands of Siglecs remain elusive. Here, we report sialylated IgG (SIA-IgG), a ligand to Siglec-7, that is highly expressed in epithelial cancer cells. SIA-IgG binds Siglec-7 directly and inhibits TCR signals. Blocking of either SIA-IgG or Siglec-7 elicited potent antitumor immunity in T cells. Our study suggests that blocking of Siglec-7/SIA-IgG offers an opportunity to enhance immune function while simultaneously sensitizing cancer cells to immune attack.

Dual Functional Amphiphilic Sugar-Coated AIE-Active Fluorescent Organic Nanoparticles for the Monitoring and Inhibition of Insulin Amyloid Fibrillation Based on Carbohydrate-Protein Interactions

Amyloid-related diseases, such as Alzheimer's disease, are all considered to be related to the deposition of amyloid fibrils in the body. Insulin is a protein hormone that easily undergoes aggregation...

Combined tetraphenylethylene fluorogens with positive charge for imaging capsule-covered pathogens

Capsule-covered pathogens can cause serious infectious diseases, and are highly pathogenic to humans. Herein, we developed four positively charged tetraphenylethylene derivatives (PC-TPEgens) that in certain combinations were applied to identify capsule-bearing pathogens using fluorescence imaging. The dual-charged probes were used to visualize the entire process of phagocytosis of pathogens into macrophages.