Protease-Responsive Potential-Tunable AIEgens for Cell Selective Imaging of TMPRSS2 and Accurate Inhibitor Screening

Comprehensive review of protein imaging with AIEgens conjugated probes: From concentration to conformation

Proteins are an essential component of living organisms, and the study of their structure and function is of great importance in biological and medical research. In recent years, the remarkable phenomenon of aggregation-induced emission (AIE) has been extensively utilized in protein detection. Significant progress has been made in the development of aggregation-induced emission luminogens (AIEgens), which have proven invaluable in protein imaging. This review highlights AIEgen-conjugated probes for imaging proteins in tumor cells through various mechanisms, including physical interactions, ligand binding, and enzymatic cleavage. These probes exploit the AIE effect to enhance the signal-to-noise ratio, providing important tools for protein research. Additionally, these probes can be used to study structural changes in intracellular protein phase separation processes, such as unfolded, misfolded, fibrous, and amorphous aggregates. The above research achievements presented lay the foundation for the widespread application of AIEgen-conjugated probes in the biomedical field and are expected to stimulate further development in related research.

Peptide-Driven Proton Sponge Nano-Assembly for Imaging and Triggering Lysosome-Regulated Immunogenic Cancer Cell Death

Triggering lysosome-regulated immunogenic cell death (ICD, e.g., pyroptosis and necroptosis) with nanomedicines is an emerging approach for turning an "immune-cold" tumor "hot"-a key challenge faced by cancer immunotherapies. Proton sponge such as high-molecular-weight branched polyethylenimine (PEI) is excellent at rupturing lysosomes, but its therapeutic application is hindered by uncontrollable toxicity due to fixed charge density and poor understanding of resulted cell death mechanism. Here, a series of proton sponge nano-assemblies (PSNAs) with self-assembly controllable surface charge density and cell cytotoxicity are created. Such PSNAs are constructed via low-molecular-weight branched PEI covalently bound to self-assembling peptides carrying tetraphenylethene pyridinium (PyTPE, an aggregation-induced emission-based luminogen). Assembly of PEI assisted by the self-assembling peptide-PyTPE leads to enhanced surface positive charges and cell cytotoxicity of PSNA. The self-assembly tendency of PSNAs is further optimized by tuning hydrophilic and hydrophobic components within the peptide, thus resulting in the PSNA with the highest fluorescence, positive surface charge density, cell uptake, and cancer cell cytotoxicity. Systematic cell death mechanistic studies reveal that the lysosome rupturing-regulated pyroptosis and necroptosis are at least two causes of cell death. Tumor cells undergoing PSNA-triggered ICD activate immune cells, suggesting the great potential of PSNAs to trigger anticancer immunity.