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Polypeptide Block Copolymers and Polymersomes

Researchers at Leiden University have developed a class of novel amphiphilic polypeptide block copolymers. The copolymers self-assemble into polymersomes which can be used as targeted drug delivery vehicles.

The technology combines for the first time solid-phase synthesis with a new method of ring-opening polymerization (ROP) to build block copolypeptides. In this process, an advantage is that any homopolymer that is formed can simply be washed away without the need for further purification steps.

The new synthetic process makes it relatively easy to control the length of the hydrophobic block, resulting in copolypeptides with well-defined block sizes and functionalities. This also makes it possible to control the thickness of the polymersome membrane, which thus far varied between 15-90 nm.

The size and properties of the hydrophilic block can also be varied by binding a variety of moieties (e.g. PEG and antibodies). In this manner the surface of the polymersomes can be functionalized for targeting of the polymersomes.

The copolypeptides are able to self assemble into polymersomes in water at neutral pH over a wide range of hydrophilic and hydrophobic block sizes and ratios. The polymersomes can also encapsulate water soluble compounds.

Cryo-TEM images of polymersomes formed from different copolypeptides/complexes.
Scale bars = 100nm.

Key benefits

  • Ease of synthesis
  • Stable and robust polymersomes
  • Variability of polymersome size and membrane thickness
  • Surface chemistry can be readily modified
  • Polymersomes encapsulate water soluble compounds


  • Drug delivery
  • Vaccines

Development stage

  • The synthesis, self-assembly and characterization of polymersomes has been carried out
  • The development of vaccines based on polymersomes is ongoing

Luris reference number


Patent status

Patent applications for the technology have been filed

Data available on request

Patent text and scientific publications