Biodegradable amphiphilic block copolymers bearing protected hydroxyl groups: synthesis and characterization

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Drug Delivery

Background:

• Development of novel biodegradable polymers is crucial for advanced biomedical applications.
• Amphiphilic block copolymers offer unique self-assembly properties for drug encapsulation.
• Functionalization of polymers enhances their utility in targeted drug delivery systems.

Purpose of the Study:

• To synthesize and characterize a new biodegradable amphiphilic block copolymer.
• To investigate the self-assembly behavior and biocompatibility of the synthesized copolymer.
• To explore the potential of the copolymer for drug encapsulation and conjugation.

Main Methods:

• Ring-opening polymerization (ROP) of L-lactide (LA) and 9-phenyl-2,4,8,10-tetraoxaspiro[5,5]undecan-3-one (PTO) using poly(ethylene glycol) (PEG) as macroinitiator.
• Characterization using Nuclear Magnetic Resonance (NMR), Fourier-Transform Infrared Spectroscopy (FT-IR), and Gel Permeation Chromatography (GPC).
• Assessment of self-assembly into micelles, critical micelle concentration (CMC) determination, cell adhesion/proliferation studies, and in vitro degradation analysis.

Main Results:

• Successful synthesis of poly(ethylene glycol)-b-poly(L-lactide-co-9-phenyl-2,4,8,10-tetraoxaspiro[5,5]undecan-3-one) [PEG-b-P(LA-co-PTO)] confirmed by spectroscopic and chromatographic methods.
• The copolymer self-assembles into micelles in aqueous solutions with a low critical micelle concentration (CMC) in the mg/L range.
• The synthesized copolymer exhibits good biocompatibility, evidenced by favorable Vero cell adhesion and proliferation, and possesses active hydroxyl groups for further modification.

Conclusions:

• The novel biodegradable amphiphilic block copolymer PEG-b-P(LA-co-PTO) is successfully synthesized and characterized.
• Its ability to form micelles with a low CMC and its biocompatibility make it a promising candidate for drug delivery.
• The presence of active hydroxyl groups allows for further functionalization, expanding its potential for drug encapsulation and conjugate development.