Abstract
Polyether urethane (PU)-based magnetic composite materials, containing different types and concentrations of iron oxide nanostructures (Fe2O3 and Fe3O4), were prepared and investigated as a novel composite platform that could be explored in different applications, especially for the improvement of the image quality of MRI investigations. Firstly, the PU structure was synthetized by means of a polyaddition reaction and then hematite (Fe2O3) and magnetite (Fe3O4) nanoparticles were added to the PU matrices to prepare magnetic nanocomposites. The type and amount of iron oxide nanoparticles influenced its structural, morphological, mechanical, dielectric, and magnetic properties. Thus, the morphology and wettability of the PU nanocomposites surfaces presented different behaviours depending on the amount of the iron oxide nanoparticles embedded in the matrices. Mechanical, dielectric, and magnetic properties were enhanced in the composites’ samples when compared with pristine PU matrix. In addition, the investigation of in vitro cytocompatibility of prepared PU nanocomposites showed that these samples are good candidates for biomedical applications, with cell viability levels in the range of 80–90%. Considering all the investigations, we can conclude that the addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.
Highlights
In recent years, the molecular imaging technique has attracted much interest due to its non-invasive procedure, which consists of a combination of in vivo imaging and molecular biology, aiming at the identification of living biological process at the cellular and molecular level [1]
The FTIR spectrum of pristine Polyether urethane (PU) showed typical bands related to the polyurethane structure: at 3326 cm−1, the absorption peak corresponding to the N-H stretching vibration could be seen; the bands at 2940 and 2854 cm−1 were assigned to the asymmetric and symmetric stretching vibration of the C–H bond in CH2 groups; at 1731 and 1700 cm−1, the peaks corresponding to the free and bonded C=O stretching of urethane could be observed; the peak at 1597 cm−1 was due to the C=C stretching vibration of MDI; at 1532 cm−1, the N-H bending band was visible; the peaks at 1412 and 1310 cm−1 were assigned to the –CH2 deformation vibration; between 1107 and 1031 cm−1, the bands corresponding to the C–O–C stretching vibration were observable [13,31,37]
Mechanical analysis showed that the PU nanocomposites presented an elastomeric behaviour, with the elongation at break increasing from 380% for pure PU up to 490% for P1-1, and reaching 530% for P2-1
Summary
The molecular imaging technique has attracted much interest due to its non-invasive procedure, which consists of a combination of in vivo imaging and molecular biology, aiming at the identification of living biological process at the cellular and molecular level [1]. MRI has the advantages of relatively high resolution (25 ÷ 100 μm) and superior tissue penetration depth, while its sensitivity requires substantial improvement compared with the direct optical imaging technique [4]. This technique is based on the principles of nuclear magnetic resonance (NMR), a spectroscopic technique used by researchers to obtain chemical and physical information about molecules [2]. Various correction methods have been developed to mitigate the corruptive effects of artifacts and to improve image diagnostic quality, most of them regarding the procedure, equipment, or postprocessing algorithms [5]. Another drawback of this method consists in the use of contrast agents that could provoke a series of hemodynamic changes, anaphylactic reactions, or side effects due to their oral or intravascular administration [3,4,6]
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