Self-assembled quantum dot-peptide bioconjugates for selective intracellular delivery.

Area of Science:

• Bioconjugation Chemistry
• Cellular Imaging
• Nanotechnology

Background:

• Semiconductor quantum dots (QDs) are valuable fluorescent probes.
• Efficient and selective intracellular delivery of QDs remains a challenge.
• Peptide-based strategies offer potential for targeted delivery.

Purpose of the Study:

• To demonstrate the use of self-assembled QD-peptide bioconjugates for selective intracellular labeling.
• To utilize a bifunctional peptide for enhanced transmembrane delivery of QDs.
• To evaluate the impact of peptide conjugation on QD cellular uptake and cytotoxicity.

Main Methods:

• Synthesis of a bifunctional peptide with oligoarginine and polyhistidine sequences.
• Self-assembly of peptides onto QD surfaces via metal-affinity interactions.
• Intracellular labeling of eukaryotic cell lines and assessment of cellular viability.

Main Results:

• Peptide-conjugated QDs showed selective intracellular delivery and labeling compared to nonconjugated QDs.
• Peptide-driven delivery was concentration-dependent and controllable.
• Internalized QDs exhibited a punctate staining pattern, with partial colocalization in endosomes.
• Differential cytotoxicity was observed based on exposure duration to QD-peptide conjugates.
• Multicolor QD labeling confirmed that peptide presence dictates cellular uptake.

Conclusions:

• Self-assembled QD-peptide bioconjugates are effective for selective intracellular cell labeling.
• The peptide facilitates transmembrane delivery and controls cellular uptake of QDs.
• This approach offers a tunable and efficient method for intracellular QD delivery with implications for cell imaging and diagnostics.