Dynamics of complex coacervate core micelles

Complex coacervate core micelles (C3Ms) can be used as encapsulators for a wide range of polar or charged (bio)molecules, like DNA, proteins and hydrophilic drugs. This is because these molecules prefer to go to the C3M core that consists of oppositely charged polyelectrolytes (the so-called complex coacervate phase). The core is protected from the environment by a neutral corona, formed by the neutral polymer block that is attached to at least one of the two polyelectrolytes. The ability to encapsulate a wide variety of compounds makes that C3Ms are now investigated for a broad range of applications, for example for drug and gene-delivery, as MRI contrast agents and in nanoparticle formation. Unfortunately, still little is known about the exchange dynamics of the C3Ms, while this dynamics can govern how often their cargo is exposed to the environment and in this way determines their encapsulating efficiency.

Project description

Following the exchange dynamics of C3Ms: C3Ms labelled with a donor fluorophore (D, green) are mixed with C3Ms labelled with an acceptor fluorophore (A, yellow). When micelle exchange occurs, donor and acceptor fluorophores can come together in the same micelle resulting in FRET from donor to the acceptor. By following the increase in FRET in time, the micelle exchange rates can be derived.
Following the exchange dynamics of C3Ms: C3Ms labelled with a donor fluorophore (D, green) are mixed with C3Ms labelled with an acceptor fluorophore (A, yellow). When micelle exchange occurs, donor and acceptor fluorophores can come together in the same micelle resulting in FRET from donor to the acceptor. By following the increase in FRET in time, the micelle exchange rates can be derived.

In this BSc or MSc thesis project you will systematically study the exchange dynamics of C3Ms. For this, you will make use of the process of Förster Resonance Energy Transfer (FRET), which occurs when a donor and acceptor fluorophore are close enough to each other. FRET can be observed by a decrease in donor fluorescence intensity and an increase in acceptor fluorescence intensity. You will make C3Ms that are labelled with a donor fluorophore and C3Ms that are labelled with an acceptor fluorophore. After mixing these C3Ms, the FRET will increase because the micelles start to exchange with each other and as a result the donor fluorophores are coming close to the acceptor fluorophores. Using an analytical model, we can quantitatively convert the FRET change to micelle exchange rates. The FRET results can be complemented with results from Langevin dynamics simulations. By smartly varying several parameters in the experimental set up, we will unravel the fundamentals of the C3M dynamics, which will enhance the rationalized design of C3Ms for a wide range of applications.

Techniques:

- fluorescence (lifetime) measurements
- static and dynamic light scattering
- chemical labelling
- Langevin dynamics simulations