Rapid Sonochemistry Approach Produces Magnetic Nanoparticles for MR imaging and Electrochemical Sensors

Abstract

The synthetic methodology impacts the performance of magnetic nanoparticles (MNPs) in several applications, including biological, sensing, and separation. In this respect, the most used approach to preparing these nanomaterials, thermal decomposition, has proven to be time-consuming, expensive, and laborious, which indicates the need for alternative synthetic methods. Sonochemistry has received increasing attention in nanomaterials synthesis because of its ability to increase the speed of nanomaterials’ production. In this sense, this work consolidates the developed sonochemistry methodology by applying the produced MNPs as a contrast agent for magnetic resonance imaging (MRI) and an electrochemical sensor for carbendazim (CBZ). Concerning the contrast agent, it is reported the use of a commercially available amino-phosphonate compound, diethylenetriaminepenta (methylene phosphonic acid, DTPMP), to functionalize Fe3O4 nanoparticles (NPs). Several characterization techniques were performed to study the properties of DTPMP-functionalized MNPs. Furthermore, relaxivity and cytotoxicity analyses confirmed the MRI contrast agent potential of the DTPMP-coated Fe3O4 NPs, presenting a non-cytotoxicity profile and high values of transverse relaxivity (357–417 mM–1 s–1). Regarding the electrochemical sensor, it was developed a highly efficient electrochemical sensor for CBZ using polyethylenimine-functionalized MNPs (@BPEI). Furthermore, a pathway for the electrooxidation reaction of CBZ was proposed based on electrochemical measurements and the oxidation products detected by mass spectrometry. Then, an electroanalytical methodology was developed using @BPEI. Our findings suggest that oxidation of CBZ occurs through the insertion of hydroxyl radicals and that the redox reaction involves the same number of protons and electrons. The LOD and LOQ values of the electroanalytical method are 3.87 × 10‒8 to 6.40 × 10‒8 and 6.17 × 10‒8 to 7.34 × 10‒8 mol L–1, respectively, which are lower than the maximum permitted level for CBZ in Brazilian regulation. Additionally, an electroanalytical methodology was successfully developed for CBZ detection in natural waters. Therefore, we can firmly affirm that this work contributed to different research fields, but connected by materials science, from analytical chemistry to medical imaging diagnosis.