Biocompatible polylactide-block-polypeptide-block-polylactide nanocarrier.

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Nanotechnology

Background:

• Poly(l-lactide) (PLLA) is a biodegradable polymer with potential applications in drug delivery.
• Incorporating functional blocks like polypeptides into PLLA can enhance its properties and introduce new functionalities.
• Developing well-defined nanostructures for efficient cargo delivery remains a significant challenge.

Purpose of the Study:

• To synthesize novel ABA triblock copolymers by initiating ring-opening polymerization of l-lactide with polypeptides.
• To fabricate and characterize PLLA-block-peptide-block-PLLA nanoparticles for cargo encapsulation and delivery.
• To evaluate the cellular uptake of these nanoparticles for potential biomedical applications.

Main Methods:

• Ring-opening polymerization (ROP) of l-lactide using polypeptides as initiators.
• Nonaqueous emulsion technique to form PLLA-block-peptide-block-PLLA nanoparticles.
• Dye encapsulation, particle characterization (size, aggregation), and cellular internalization studies using Coherent Anti-Stokes Raman Spectroscopy (CARS) and fluorescence microscopy.

Main Results:

• Successfully synthesized PLLA-block-peptide-block-PLLA triblock copolymers with controlled molecular weights and low polydispersities, indicating living polymerization.
• Fabricated well-defined PLLA-block-peptide-block-PLLA nanoparticles (average diameter 100 nm) capable of dye encapsulation.
• Demonstrated successful internalization of the nanoparticles by HeLa cells without significant dye leakage or aggregation in aqueous media.

Conclusions:

• Polypeptide-initiated ROP provides a viable route to synthesize well-defined PLLA-based triblock copolymers.
• The resulting nanoparticles are stable, efficiently encapsulate cargo, and are internalized by cells.
• These PLLA-block-peptide-block-PLLA nanoparticles show significant promise as versatile cargo delivery vehicles.