Synthesis of magnetic nanoparticles and infiltration through dentine disc with magnetic field for application in drug delivery to dental pulp

Abstract

In this work, Polypoly(ethylene glycol) monomethyl ether methacylate (PPEGMA) coated magnetic nanocomposite (PPEGMA-MNCs) size series were synthesized. The MNCs were coated with PPEGMA via Atom Transfer Radical Polymerization (ATRP). Their sizes are in the range of 20-200 nm. All of them are well-dispersed in water-based solution and biocompatible. Moreover, after they were coated with PPEGMA, they still exhibited magnetic response with superparamagnetic character but weaker than pristine magnetic NPs. The MNCs of 24.86±4.38, 45.24±5.00, 98.10±8.88 and 202.22±6.70 nm in diameter were obtained as measured by transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) was used determination of % weight of PPEGMA on MNCs showing the weight loss of 86%, 64%, 33% and 30% for PPEGMA-MNCs for the MNCs of 20, 40 100 and 200 nm, respectively. These MNC size series were studied for the infiltration through a dentine disc. The results indicated that they cannot be infiltrated through dentine discs with an external magnet. Additionally, we studied the infiltration of the pristine magnetic NPs (MNPs) in two systems. In the first system, MNPs were stabilized with oleic acid and dispersed in cyclohexane (Mc), while the other MNPs were stabilized with aminoethoxysilane (APS) and dispersed in ethanol (Me). The infiltration results indicated that MNPs can pass through dentine discs for 2.87% and 0.65% of the starting concentration for the infiltration of Mc and Me, respectively. The differences in magnetization of MNPs and MNCs suggested that the MNCs cannot be infiltrated through dentine discs because their magnetic property is very weak. From these studies, we demonstrate that the magnetic nanoparticles with enough magnetization can be applied in the development of new techniques for root canal treatments and can be useful in as a new clinical approach in dentistry.