Adsorption of serum protein in chitosan-coated and polyethyleneimine-coated magnetite nanoparticles

Abstract

Magnetic nanoparticles have been developed for a variety of biomedical applications including gene therapy. Magnetite nanoparticles (MNP) stands out nowadays as a non-viral vector for transfection when combining with a cationic polymeric coating. However, to ensure its performance as a non-viral transfection agent, the interaction of nanomedicine systems with biomolecules in blood plasma should be evaluated. This work aims to study the serum protein adsorption, namely opsonization, that could lead the MNP being excreted if they were exposed to in vivo systems. MNP were synthetized by coprecipitation method and further coated with chitosan (MNP-Ch), as well as coated with polyethyleneimine (MNP-PEI). Dynamic Light Scattering (DLS) reveled average diameters of 68± 65 nm nm for uncoated-MNP, 453 ± 332 nm nm for MNP-Ch and 817 ± 340 nm for MNP-PEI, individual MNP presented a size of 10nm. In this way, the increase in size is attributed to the formation of agglomerates. The spherical shape and size, as well as the elements in the samples were confirmed using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). Likewise, Fourier-transform infrared spectroscopy (FTIR) corroborated bands at 578 cm-1 due to Fe-O bond, while the bands at 1468 cm-1 in MNP-Ch and 1380 cm-1 and 1620 cm-1= in MNO-PEI was attributed to the vibratory stretching mode of C-N, symmetrical and asymmetrical elongations of carboxylic groups, respectively. Additionally, Raman spectroscopy showed bands at 291, 598 y 1300 cm-1 for MNP, 584 and 1249 cm-1 in chitosan and MNP-Ch, as well as bands at 1065 and 1320 cm-1 for PEI and MNP-PEI. To measure the protein adherence, a bovine serum albumin (BSA) in PBS calibration curve was made using Nanospectrophotometer at wavelength 280 nm. Both graphics, MNP-Ch and MNP-PEI showed that coated nanoparticles have a BSA absorption greater than bare MNP.