Quantum dot-carrier peptide conjugates suitable for imaging and delivery applications

Area of Science:

• Biotechnology
• Nanomedicine
• Molecular Biology

Background:

• Nonviral delivery of nucleic acids remains a challenge.
• Quantum dots (QDs) offer unique optical properties for imaging.
• Developing safe and efficient delivery vehicles is crucial for RNA therapeutics.

Purpose of the Study:

• To develop multifunctional fluorescent nanoparticles for nonviral delivery of negatively charged molecules, specifically RNA.
• To characterize the stability, toxicity, and cellular uptake of QD-peptide bioconjugates.
• To demonstrate the efficacy of these nanoconstructs for intracellular RNA transport and endosomal escape.

Main Methods:

• Conjugation of a branched peptide (hCT(18-32)-k7) to luminescent quantum dots (QDs).
• Characterization of QD-peptide conjugate stability, toxicity, and cellular uptake mechanisms (endocytosis).
• In vitro RNA delivery studies into various cell lines, including assessment of endosomal escape using chloroquine.

Main Results:

• QD-peptide bioconjugates demonstrated high stability and no adverse effect on cell viability.
• Multiple endocytotic pathways were involved in cellular internalization.
• Efficient intracellular transport of Cy-3 labeled RNA was achieved.
• Chloroquine facilitated endosomal escape of the nanoconstructs.

Conclusions:

• Multifunctional fluorescent nanoparticles are effective for nonviral RNA delivery.
• These platforms are versatile tools for diagnostic and therapeutic imaging.
• The developed nanoconstructs show potential for delivering biologically active sequences like siRNA and aptamers.