Utilizing advanced field functions to drive the assembly and disassembly of magnetic particles

• Online Access: http://hdl.handle.net/2047/D20254628

Directed assembly of particle suspensions in massively parallel formats, such as with magnetic fields, has application in rheological control, smart drug delivery, and active colloidal devices from optical materials to microfluidics. At the heart of these applications lies a control optimization problem for driving the assembly and dissolution of highly monodisperse particle clusters. This control problem quickly becomes complex when considering high-order magnetic interactions, near-field and far-field hydrodynamics, Brownian motion, and advanced magnetic field functions characterized by three-axes of incoherent, oscillating magnitudes. In this work, theoretical, numerical, and experimental approaches have been investigated in parallel to study the assembly behavior of particle suspensions in presence of advanced magnetic field functions. Applying such magnetic fields to suspensions of magnetic particles enables unprecedented control over the assembly of particle clusters. These findings were leveraged within the field of magnetic drug targeting for possible treatment of pancreatic cancer. Specifically, a novel five-step drug delivery scheme was developed in which drug-laden magnetic nanoparticles (coated with rosette nanotubes and small interfering RNA) can be (1) self-assembled in a carrier fluid, (2) transported to the tumor site with continuous fields and field gradients; (3) driven to penetrate through the porous fibrotic tissue encapsulating a pancreatic tumor with advanced field functions; (4) get endocytosed within tumor cells; (5) and effectively deliver small interfering RNA to disrupt the translation of messenger RNA to silence genes critical to cancer proliferation. In this case, it is shown, both insitu and in-vitro, that the suggested system can lead to a higher drug delivery efficiency in comparison with current existing techniques.