Homogeneous Embedding of Magnetic Nanoparticles into Polymer Brushes during Simultaneous Surface-Initiated Polymerization

Abstract

Here we present a facile and efficient method of controlled embedding of inorganic nanoparticles into an ultra-thin (<15 nm) and flat (~1.0 nm) polymeric coating that prevents unwanted aggregation. Hybrid polymer brushes-based films were obtained by simultaneous incorporation of superparamagnetic iron oxide nanoparticles (SPIONs) with diameters of 8–10 nm into a polycationic macromolecular matrix during the surface initiated atom transfer radical polymerization (SI-ATRP) reaction in an ultrasonic reactor. The proposed structures characterized with homogeneous distribution of separated nanoparticles that maintain nanometric thickness and strong magnetic properties are a good alternative for commonly used layers of crosslinked nanoparticles aggregates or bulk structures. Obtained coatings were characterized using atomic force microscopy (AFM) working in the magnetic mode, secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS).

Tailoring cellular microenvironments using scaffolds based on magnetically-responsive polymer brushes

“…Superparamagnetic iron oxide nanoparticles (SPIONs) were successfully embedded into polymer brushes matrix via simultaneous surface-initiated atom transfer radical polymerization (SI-ATRP) using the method previously described by us. 38 The SPIONs applied here were obtained by coprecipitation of the individual iron salts in an aqueous medium, and were characterized in terms of their size, stability of their dispersion, and their magnetic properties. The average diameter of the nanoparticles was found to be 8.0 AE 1.1 nm using transmission electron microscopy (Fig.…”

“…All of these parameters correlate well with the previously reported results. 38,40 The obtained bare polyelectrolyte brushes (poly(APTAC)) and the same brushes with the incorporated SPIONs (poly(APTAC) + SPIONs) were studied using AFM. The thickness of the polymeric layers in the dry state was determined to be 153.2 AE 2.8 nm for the poly(APTAC) brushes and 109.0 AE 2.6 nm for the poly(APTAC) + SPIONs, as shown in Fig.…”

“…2A and C, respectively. The smaller thickness of the brushes with the embedded nanoparticles is typical, 38 and it can be briefly explained by the mechanical integration of SPIONs into the polymeric layer by the cross-linking of the chains. The topography images showed distinct differences between both samples.…”

“…The obtained results correlate with the previously obtained data for the thin polymer layers with the SPIONs. 38 The N1s band is separated into two peaks: 399 eV for the terminal cationic group -N + (CH 3 ) 3 and 403 eV for -C-N-in the main APTAC chain. Furthermore, the XPS spectra enable the observation of the presence of a thin layer of PLL on the top of the poly(APTAC) + SPIONs brushes.…”

“…36 In this work, we have focused on a magnetically-responsive material based on the nanocomposite of superparamagnetic iron oxide nanoparticles (SPIONs) 37 homogeneously distributed within surface-grafted polyelectrolyte brushes obtained in simultaneous surface-initiated atom transfer radical polymerization (SI-ATRP). 38 The presented approach leads to the formation of a dynamic magnetic thin layer response to a magnetic field that was successfully used as a scaffold culture neuroblastoma cell, and to test the magnetically-triggered detachment of the living cells. Such studies, especially in tumour microenvironments, are of major importance for improving the effectiveness of cancer treatment and understanding the mechanisms of processes governing changes in differentiation status.…”