Protein encapsulation in biodegradable amphiphilic microspheres.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Polymer Chemistry

Background:

• Poly(lactic acid) (PLA) microspheres are widely used for drug delivery.
• Controlling drug release kinetics and minimizing non-specific adsorption remain challenges.
• Methoxy Poly(ethylene oxide)-Poly(lactic acid) (MPOE-PLA) copolymers offer tunable properties for improved performance.

Purpose of the Study:

• To prepare and characterize MPOE-PLA microspheres for enhanced bovine serum albumin (BSA) delivery.
• To investigate the effect of MPOE coating on microsphere surface properties and BSA release kinetics.
• To elucidate the relationship between MPOE chain characteristics and drug diffusion within the microspheres.

Main Methods:

• Double emulsion method for MPOE-PLA microsphere preparation.
• Confocal scanning microscopy for surface analysis and MPOE coating visualization.
• Atomic force microscopy (AFM) for surface roughness assessment.
• Diffusion studies using rhodamine aqueous solution to evaluate water penetration.

Main Results:

• High encapsulation efficiency (~93%) achieved for BSA-loaded MPOE-PLA microspheres.
• MPOE coating confirmed on microsphere surfaces, leading to reduced BSA adsorption and increased BSA release.
• Surface roughness was observed due to the presence of MPOE chains.
• Fast water diffusion through MPOE-PLA matrices, particularly with high molecular weight MPOE, correlated with rapid BSA release.

Conclusions:

• MPOE-PLA microspheres demonstrate improved performance as a drug delivery system compared to plain PLA.
• The MPOE hydrophilic chains effectively reduce protein adsorption and enhance drug release.
• The findings suggest MPOE-PLA microspheres are a promising platform for controlled protein delivery.