MMP-2 sensitive poly(malic acid) micelles stabilized by π-π stacking enable high drug loading capacity

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Poly(β-l-malic acid) (PMLA) derivatives are promising aliphatic polyesters for anti-tumor drug delivery.
• Polyester-based micelles often face challenges with low drug loading and premature drug release.

Purpose of the Study:

• To develop novel poly(β-benzyl malate)-b-polyethylene glycol (PBM-PEG) micelles with improved drug loading and stability.
• To create a tumor-specific drug delivery system utilizing MMP-2 sensitive linkers and cell-penetrating peptides.

Main Methods:

• Micelle formulation using PBM-PEG copolymers.
• Drug loading studies with doxorubicin (DOX).
• In silico computer simulations to assess binding free energy.
• Incorporation of TAT peptide and PEG5k via an MMP-2 cleavable linker.

Main Results:

• PBM-PEG micelles demonstrated high drug loading capacity (>20 wt%) and robust stability.
• π-π stacking interactions contributed to micelle stability and drug binding.
• Computer simulations confirmed strong binding affinity between PBMs and DOX.
• MMP-2 sensitive cleavage exposed TAT peptide at tumor sites, enhancing cellular uptake.
• Effective tumor targeting and therapeutic effects were observed with no systemic toxicity.

Conclusions:

• MMP-2 sensitive PBM polymeric micelles represent a promising platform for targeted anti-tumor drug delivery.
• The developed system overcomes limitations of premature drug release and low drug loading.
• Enhanced cellular internalization and therapeutic efficacy with reduced systemic toxicity were achieved.