enzymeCOMP · Phase-separated block copolymer nanoparticles for spatial organization of enzymes: A new strategy to control enzyme cascade reactions

Phase-separated block copolymer nanoparticles for spatial organization of enzymes: A new strategy to control enzyme cascade reactions

Nature has developed a unique set of mechanisms to control biological functions through compartmentalization of functional macromolecules such as enzymes. Inspired by this high level of control, there is an increasing interest in mimicking such accurate spatial separation on synthetic colloidal materials. However, most current approaches show limited spatial control over chemical functionalities. Consequently, new strategies are needed to localize functional (macro)molecules in colloidal materials with more precision. To address this need, the phase-separation of block copolymers (BCP) in colloidal confinements is a promising strategy to generate particles with well-defined chemical patterns. Especially, striped ellipsoidal particles are of interest due to their well-defined lamellar pattern of alternating chemical domains on the particle surface. Thus, the development of domain-specific functionalization strategies would open up new biomimetic applications such as compartmentalization of cascade enzymes. Working towards this vision, different strategies have been reported but either focus on the functionalization of the particle interior or are limited to the functionalization of a single domain. Thus, this project developed two different strategies to overcome current shortcomings in domain-specific surface functionalization of striped ellipsoidal BCP particles: (1) Surface functionalization through external surfactants: Two different block-selective surfactants are designed to interact each with a specific block of the structure-forming BCP during the particle preparation. This results in patterned particle surfaces where the functionality of the stripes is now determined by orthogonally reactive end-groups of the surfactants. (2) Surface functionalization through internal domains. Reactive monomers are incorporated by domain-specific swelling after the particle formation. Subsequent polymerization introduces additional reactivity into the different domains. This translates from the domain interior to the surface of the particles, which allows further domain-specific surface functionalization. Detailed investigations on both strategies revealed the importance of fundamental examinations to get a more thorough understanding of the underlying principles and select the most promising strategy. A careful comparison demonstrated the synthetic flexibility and versatility of approach (2), which introduces the reactivity after the particle preparation. Thus, established routes to striped ellipsoids can be used to circumvent elaborate optimizations of phase-separation conditions, which are needed in strategy (1). In addition, strategy (2) enables the preparation of novel anisotropic lamellar thicknesses, which enables a new level of spatial control over the chemical functionality.

Data: CORDIS, © European Union