Radboud University Nijmegen is applying nanoparticle tracking analysis (NTA) to study molecular machines.
Daniela Wilson and her team at the Institute for Molecules and Materials (IMM), Radboud University are working on nano-sized rockets which may provide a solution for delivering drug packages in the human body.
Wilson explains: “Making a nanomotor has been a dream of many researchers in nanotechnology. From molecular machines to micron size self-propelling rods, our team has used a combination of bottom-up or top-down approaches taking years off synthetic work.
“We applied self-assembly as a tool just like the pieces of a puzzle. The only difference is that we allowed the building blocks make itself to form 350 nm sized motors. The next step was to prove the concept.
“Having constructed these sub-micron sized nanomotors, we could not use conventional microscopies to visualize them.For 350 nm size particles, we required a special technique and this is how we have come to be users of the NanoSight technique of nanoparticle tracking analysis, NTA.
“This tracks the motors one by one (in effect, particle-by-particle). We could even analyze their movement after the addition of their fuel (hydrogen peroxide).”
Wilson continued: “Knowing the particle size was very important to establish the size distribution of our self-assembled nanomotors as well the entrapment of the catalytic particles inside the bowl shape structures. However, even more important for us was the ability to track the movement of the motors in the presence of the fuel. This provided the definitive proof of directed motion resulting from the fast discharge of oxygen.”
Prior to using NTA, the IMM group used dynamic light scattering (DLS). While quite powerful to measure size, it did not provide the ability to track individual particles that was essential for this research.
Furthermore, it was vital to be able to analyze particle movement in real time. NanoSight uses tracking and scattering information to provide the size of the particles as well as giving information about the purity of its components.
Different refractive indexes materials within the same colloidal distribution will give different scattering and therefore the group is able to use that information to assess the purity and distribution of complex mixtures.
