Bifunctional (Zn,Fe)3O4 nanoparticles: Tuning their efficiency for potential application in reagentless glucose biosensors and magnetic hyperthermia

In a new approach based on a two-step procedure, co-precipitation method followed by hydrothermal treatment in a microwave field, Zn-substituted Fe3O4 nanoparticles (ZnxFe3-xO4) were synthesized. Results of XRD, FT-IR and TEM analysis clearly demonstrate that nanoparticles were single phase, crystallizing in the spinel structure type (S.G. Fd (3) over barm) with crystallite size in the range of 2-20 nm, which strongly depends on Zn concentration. The produced nanoparticles were used for fabrication of modified carbon paste electrodes as a novel system for electrochemical non-enzymatic glucose detection. It was found that the increase of zinc concentration up to the value of x = 0.56 (Zn0.56Fe2.44O4) of as-prepared nanoparticles was followed with an increase of a performance of the modified carbon paste electrode toward glucose detection. Linear working range from 0.1 to 2 mM was obtained with detection limit of 0.03 mM, and with fast response time (<3 s). Proposed sensor was successfully applied for the determination of glucose level in real samples with satisfactory recovery. The synthesized zinc-ferrite samples were also tested as potential heating agents in magnetic hyperthermia. The heating ability (SAR value) increases with x value, reaching maximum for x = 0.37. This is correlated with changes of particle size and magnetic characteristics which strongly depend on Zn concentration. (C) 2018 Elsevier B.V. All rights reserved.