Morphology-Dependent Cell Imaging by Using a Self-Assembled Diacetylene Peptide Amphiphile

Area of Science:

• Supramolecular Chemistry
• Nanotechnology
• Biomedical Imaging

Background:

• Cationic peptide gemini amphiphiles offer unique self-assembly properties.
• Diacetylene motifs can undergo polymerization upon specific stimuli.
• Developing novel probes for cell imaging remains a key challenge in cell biology.

Purpose of the Study:

• To synthesize and characterize a novel cationic peptide gemini amphiphile with diacetylene motifs (DA2P).
• To investigate the self-assembly behavior of DA2P at different concentrations.
• To explore the potential of DA2P assemblies as a cell imaging probe, particularly their polymerization and cellular uptake characteristics.

Main Methods:

• Synthesis and characterization of the DA2P amphiphile.
• Self-assembly studies using techniques to determine nanostructure morphology (e.g., TEM, DLS).
• Cell incubation experiments with HeLa cells to observe polymerization and cellular uptake, coupled with fluorescence microscopy.

Main Results:

• DA2P self-assembles into tadpole- and bola-shaped nanostructures at low concentrations and nanofibers at higher concentrations.
• DA2P assemblies polymerize into a red fluorescent phase specifically upon incubation with HeLa cells, attributed to cell membrane interaction.
• Cellular uptake is morphology-dependent: vesicles, tadpole-, and bola-shaped assemblies enter cells, while nanofibers do not.

Conclusions:

• DA2P is a versatile cationic peptide gemini amphiphile capable of forming diverse nanostructures.
• The cell-specific polymerization of DA2P into fluorescent assemblies offers a novel platform for cell imaging.
• The observed morphology-dependent cellular uptake highlights the importance of nanostructure design for intracellular delivery and imaging applications.