Viral protein nanocages, such as that of the cowpea chlorotic mottle virus (CCMV), are promising carriers for drug delivery applications or capsules for artificial organelle construction. For therapeutic applications a therapeutic agent should be encapsulated inside the capsids, which can be facilitated via modification of the capsid interior. In order to improve the in vivo stability and targeting, the exterior of the capsid can be modified with stabilizing or targeting agents.
It has been shown that proteins can be successfully encapsulated via Sortase A-mediated N-terminal modification of CCMV. Hereto an LPXTG-tag (where X is any amino acid) must be present at proteins to encapsulate them via this Sortase reaction. In this project, the master student will develop a method to encapsulate enzymes in which for example, first a click-reaction between an LPXTG-peptide and a therapeutic enzyme is performed, followed by encapsulation of the enzyme via the Sortase reaction. If successful, in vitro studies will be performed to determine the activity of these encapsulated enzymes.
Viral protein nanocages, such as that of the cowpea chlorotic mottle virus (CCMV), are promising carriers for drug delivery applications or capsules for artificial organelle construction. The natural CCMV coat protein assembles spontaneously at pH 5.0 in the absence of its native RNA cargo, while it reversibly disassembles into dimers at pH 7.5. Via introduction of a stimulus-responsive elastin-like polypeptide (ELP) block at the N-terminus of the viral coat protein, we have established capsid assembly under physiological conditions (pH 7.5). As such we are very close to applying the CCMV capsid in vivo.
In order to enhance the stability of the ELP-CCMV capsid in vivo, while maintaining its reversible disassembly behavior, the N-terminal ELP block can be modified via protein engineering. Based on a small library of ELP-CCMV variants that are currently available, the master student will design novel ELP-CCMV variants with intermediate hydrophobicity. Via the protein engineering toolbox, these variants can be produced and their assembly behavior and stability should then be evaluated and compared to the currently available variants. If successful, cellular uptake experiments of the assembled capsids can be performed.
Polymersomes are an interesting group of polymeric (micro/nano) vesicles. These vesicles are formed due to the self-assembly of amphiphilic block copolymers into a well-defined nano/micro structure (100- 500 nm). For biological systems (uptake, cell response, etc.) the morphology (size, shape, membrane thickness) of these polymersomes is highly important and, consequently, we are interested in controlling and understanding these parameters.
The goal of this master project is to use computer simulations to calculate the folding of the used block copolymers and its interactions, to correlate its composition to the morphology of the polymeric vesicles.
In the past decades, a large number of novel formulations of drug delivery systems have been published. However, only a small percentage of them actually follow their way through clinical trials. One of the parameters of formulation we might forget in order to reach success, is particle morphology. Mimicking design principles and characteristics of natural objects, we can think of engineering functional nanomaterials with different morphologies. Small changes in the chemical components used in any nanoparticle fabrication process (building blocks, solvents, conditions as concentration/temperature/pH/salt behaviour, etc.) can have substantial effects upon the resulting structure (size, shape, stiffness, surface chemistry, etc.), which can obviously change the in vitro/in vivo performance.
Micelles are self-assembled nanoparticles formed through the hydrophobic re-arrangement of amphiphilic molecules into a thermodynamically favorable spheroid. The hydrophobic portion of the block copolymer will self-associate into the micellar core whereas the hydrophilic portion will form the external corona. Importantly, the micelle core is capable of encapsulating hydrophobic drugs. By varying the right parameters, micelles can undergo a shape change into worm-like structures. This is the aim of the project.
Stimulus-responsive particles for nanomedicine
Nanomedicine is regarded as one of the most promising developments to improve the efficacy of a wide range of biomedical activities, such as drug delivery and vaccination. For this purpose, nanoparticles need to be constructed with tailor-made size, shape and surface functionality. In this BEP students will construct the polymer building blocks, either via protein engineering or polymer chemistry, and investigate the assembly process. They will study how the particle properties depend on environmental changes such as pH and temperature.