Polymeric Micelles in Targeted Drug Delivery Systems

Polymeric micelles are nanoscale assemblies formed by the self-aggregation of amphiphilic block copolymers above a critical concentration. In aqueous environments, the hydrophobic blocks coalesce to form a core that encapsulates poorly water-soluble therapeutics, while the hydrophilic corona stabilises the structure and prolongs circulation. Typical sizes range from 10 to 100 nm, enabling passive accumulation in diseased tissues via the enhanced permeability and retention effect. Surface functionalisation with targeting ligands or stimuli-sensitive linkages allows active homing to specific cells and controlled release in response to pH, enzymes or redox conditions. These features combine to improve solubility, reduce off-target toxicity and enhance therapeutic indices. Despite considerable progress, challenges remain in achieving reproducible large-scale manufacture, in vivo stability against dilution and rapid clearance, and optimisation of drug-loading capacity versus release kinetics. Ongoing research strives to balance these parameters to realise clinically viable, multifunctional micellar carriers.

Research from Nature Portfolio

Recent studies have demonstrated the potential of mixed micelles composed of Pluronic F127 and tocopheryl polyethylene glycol succinate to traverse the blood–brain barrier. These hybrid assemblies measure around 20 nm in diameter and exhibit an exceptionally low critical micelle concentration, ensuring stability upon dilution. In vitro release profiles show sustained liberation of a fluorescent tracer, while cellular assays confirm enhanced uptake by brain capillary endothelial cells. Furthermore, spontaneous incorporation of a model enzyme into the same carriers achieves efficient delivery and accumulation in brain tissue, illustrating a versatile platform for cerebral targeting of both small molecules and biologics.

Polymeric Micelles in Targeted Drug Delivery Systems publication trend

The graph below shows the total number of articles in polymeric micelles in targeted drug delivery systems across all publications each year (not limited to Nature Index journals).

Technical terms

Amphiphilic block copolymer: A polymer composed of covalently linked hydrophilic and hydrophobic segments that self-assemble in selective solvents.

Critical micelle concentration (CMC): The minimum polymer concentration at which micelles form in solution.

Enhanced permeability and retention (EPR) effect: The passive accumulation of nanoparticles in tumour or inflamed tissues due to leaky vasculature and poor lymphatic drainage.

Core–shell structure: A micelle architecture in which a hydrophobic core encapsulates cargo and a hydrophilic shell confers steric stability.

Stimuli-responsive micelle: A nanocarrier engineered to change its assembly or release profile in response to environmental triggers such as pH, temperature or enzymes.

References

1. Controlling the function of bioactive worm micelles by enzyme-cleavable non-covalent inter-assembly cross-linking. Journal of Controlled Release (2024).
2. Unravel the Tangle: Atomistic Insight into Ultrahigh Curcumin‐Loaded Polymer Micelles. Small (2023).
3. Block copolymer micelles as ocular drug delivery systems. Drug Discovery Today (2024).
4. A Review of Polymeric Micelles and Their Applications. Polymers (2022).
5. Pluronic F127 and D-α-Tocopheryl Polyethylene Glycol Succinate (TPGS) Mixed Micelles for Targeting Drug Delivery across The Blood Brain Barrier. Scientific Reports (2017).