Applications of Magnetic Helical Nanomotors From Cancer Biology to Dentistry

Abstract

Micron/nano sized machines promise precise targeting and drug-delivery at hard to reach places inside the human body. There have been tremendous efforts in this direction and various remotely powered artificial nanomachines have been designed and experimented during the last decade by researchers. In this thesis, we explore the possible applications of magnetically driven artificial nanomotors under in-vivo conditions. We have demonstrated through a series of experiments, a synergistic application potential of nanomotors where they can sense localized changes in viscosity in fluids, discover new physico-chemical phenomenon in complex tumor-like environments and deliver therapy in hard-to-reach bacteria-infected rigid dental tissues. First, we will discuss the ability of nanomotors to measure viscosity for Newtonian as well as non-Newtonian fluids in heterogenous environments a development that would be especially useful in biophysical measurements, such as a tissue. We demonstrate, by imaging the orientational dynamics of nanomotors under the action of a rotating magnetic field, measurement of the viscosity of a fluid. This, when combined with the remotely controlled maneuverability of a nanomotor, allows us to observe the real-time spatial viscosity changes while the nanomotor swims through a heterogenous mixture of fluids. It was also possible to measure the temporal variation of the viscosity, achieved through controlled temperature changes in the microfluidic device. Next, we describe how maneuvering nanomotors allow us to study cancer induced heterogeneity in a tumor model. We have moved the nanomotors through the complicated landscape of extracellular matrix using specially designed thinner nanomotors matched to the porosity of the protein mesh found in such matrix scaffolds. Nanomotors are found to adhere to the matrix secreted by cancer cells, whereas they were observed to move past normal cells...