Abstract
A facile sol-gel route has been applied to synthesize hybrid silica-PVA-iron oxide nanocomposite materials. A step-by-step calcination (processing temperatures up to 400 °C) was applied in order to oxidize the organics together with the iron precursor. Transmission electron microscopy, X-ray diffraction, small angle neutron scattering, and nitrogen porosimetry were used to determine the temperature-induced morpho-textural modifications. In vitro cytotoxicity assay was conducted by monitoring the cell viability by the means of MTT assay to qualify the materials as MRI contrast agents or as drug carriers. Two cell lines were considered: the HaCaT (human keratinocyte cell line) and the A375 tumour cell line of human melanoma. Five concentrations of 10 µg/mL, 30 µg/mL, 50 µg/mL, 100 µg/mL, and 200 µg/mL were tested, while using DMSO (dimethylsulfoxid) and PBS (phosphate saline buffer) as solvents. The HaCaT and A375 cell lines were exposed to the prepared agent suspensions for 24 h. In the case of DMSO (dimethyl sulfoxide) suspensions, the effect on human keratinocytes migration and proliferation were also evaluated. The results indicate that only the concentrations of 100 μg/mL and 200 μg/mL of the nanocomposite in DMSO induced a slight decrease in the HaCaT cell viability. The PBS based in vitro assay showed that the nanocomposite did not present toxicity on the HaCaT cells, even at high doses (200 μg/mL agent).
Highlights
In the past years great efforts have been dedicated to synthesizing superparamagnetic iron oxide nanoparticles, as promising materials for various applications: contrast agent in magnetic resonance imaging (MRI) [1], biocatalyst [2], biomarker [3] and biosensor [4], carrier for drugs [5], and nanomedicine for magnetic hyperthermia treatment [6]
The nanocomposites are named as P-x, where x is the temperature of thermal treatment
The silica-iron oxide composite material thermal stability and the temperatures for iron oxide crystalline phase formation were determined by thermal analysis
Summary
In the past years great efforts have been dedicated to synthesizing superparamagnetic iron oxide nanoparticles, as promising materials for various applications: contrast agent in magnetic resonance imaging (MRI) [1], biocatalyst [2], biomarker [3] and biosensor [4], carrier for drugs [5], and nanomedicine for magnetic hyperthermia treatment [6]. For biomedical applications the nanoparticles are usually prepared in colloidal medium [7], where the absence of a specific coating leads to the formation of aggregates and, to agglomeration, with the latter being an irreversible process [8]. Various synthetic processing methods have been developed to avoid the agglomeration [9,10], with the most promising seeming to be the incorporation in silica matrices [11]. To be accepted for bio-related applications, these materials need to possess specific features, such as: nanoscale sizes, proper shape, biocompatibility, lack of toxicity, and biodegradation [14]. Silica carriers, assuring the ability of material to accomplish its envisaged job, fulfill these requirements
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