New Nanoparticle Technology For Controlling Size And Shape—MORPH

For decades, scientists have been studying how to make better use of nanoparticles in medicine. Nanoparticles are much smaller than normal cells and are more similar in size to proteins. This makes them good at interacting with biomolecules and transporting drug molecules attached to their surface through cell membranes. However, to date, only a few nanoparticle-based drugs have successfully entered the clinic. This is because there are challenges in controlling the size and shape of nanoparticles. However, although chemists have become skilled in manipulating molecules, it is even more challenging to achieve the same level of control at the nanometer level (just raising it to one level). In particular, highly heterogeneous structures are a natural target for nano-sized self-assembly because they are ubiquitous in biology (e.g., microtubules, muscle filaments) and have proven to have unique properties in various applications, such as drugs deliver. The ideal structure of bottom-up self-assembly requires anisotropic nanoparticles to meet the following conditions: (1) easy to obtain (ie, cheap and scalable synthesis method), (2) chemical composition can be adjusted directly (so it can be used for different applications and Tailor-made materials) and (3) fine-grained control over the size of the nanoparticles. However, combining all three of these requirements has proven difficult.

In a new study published in Nature Communications, researchers at the University of Birmingham and the University of Bath demonstrated a technology, MORPH, that can be used to produce anisotropic polymer nanoparticles with well-defined aspect ratios. The significance of this technology is that the shape of the nanoparticles can be changed , such as, from spherical to cylindrical, this can have a huge impact on the interaction of the nanoparticles with cells in the body and how they are distributed through the nanoparticles. With the ability to control size and shape, researchers can begin to design and test nanoparticles that are perfectly suited for their intended function.

The basic principle of this technology is: a basic nanoparticle made of a polymer, and then a second polymer is added to the solution. When designing basic nanoparticle, the second polymer chimeric position is reserved on the basic nanoparticle, so the second polymer can insert into the nanoparticle core, forcing it to swell. Then,  the exact size and shape of the nanoparticles can be determined by controling the amount of second polymer is added.

The nanoparticles produced by MORPH show many useful characteristics: these nanoparticles are easy to assemble because they are the thermodynamic products of a simple self-assembly process; these nanoparticles are possible to accurately controlling shape and size changes by mixing the nanoparticle solution with a complementary polymer solution; the global transformation process makes it easy to integrate additional functions group in nanostructures. Therefore, researchers can combine functional ligands, therapy drug and fluorophore to create a highly controlled, multifaceted delivery platform. In future work, particles like this could be used to explore the precise effect of aspect ratio on nanoparticles interaction with cells. Most importantly, the pre-existing model has shows that it is possible to control the growth of nanoparticles using the huge diversity and deformation of supramolecular binding motifs, so it could be a valuable complement to the self-assembly toolbox.