Biomagnetic interaction of functionalized iron oxide nanoparticles with bovine serum albumin

Functionalized iron oxide (magnetic) nanoparticles are promising candidate for detection and sensing of target molecule as they can be manipulated and detected through magnetic interactions. The biological recognition moiety of the functionalized coating results in binding of the target analyte which causes a change in the interaction of the nanoparticles under the influence of an external magnetic field. This forms the basis of the fabrication of a bio-magnetic sensor. The current study reports the use of three different macromolecules viz. glycol chitosan (GC), poly ethylene glycol methyl ether (PEGME) and poly sodium stereo-4 sulphate (PSSNa) to functionalize and cap the magnetic nanoparticles. The magnetic nanoparticles were characterized using FTIR, XRD, TEM and TGA to evaluate their structural and surface properties. TEM showed spherical nanoparticles with mean size of ~11, 12 and 13 nm for GC, PEGME and PSSNa-MNPs respectively. TGA evaluates the weight loss of the modified MNPs and confirms the coating on the surface of the MNPs. Bovine serum albumin (BSA) was immobilized on the functionalized MNPs and detection studies were carried out using AC susceptibility studies on a physical property measurement system. Detection of BSA immobilized MNPs was exhibited at 300 K by the measurement of the imaginary part of the magnetic susceptibility over a frequency range and is based on the changes of dynamic magnetic properties of the MNPs, making use of the Brownian relaxation.