Abstract
This study aimed to investigate the influence of surface modification of ZnAl1.9Eu0.05O4 nanoparticles for obtaining hybrid ZnAl1.9Eu0.05O4/SiO2 for application as a biosensor. Initially ZnAl1.9Eu0.05O4 nanoparticles were synthesized by combustion reaction and, subsequently, their surfaces were modified with silane agent. The samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and excitation and emission spectroscopy. The results showed formation of ZnAl2O4 as the major phase. By SEM, hard agglomerates, irregularly shaped in the form of plaques, with the presence of few irregular and variables pores were observed. The surface modification was confirmed by FTIR through the silanol and siloxane groups. The excitation and emission spectra revealed the presence of a broadband of ZnAl2O4 matrix, and fine and intense transitions from europium ion arising from doping of non-stoichiometric ZnAl2O4 with the europium. From the results of emission and excitation, it was observed that the luminescence of ZnAl1.9Eu0.05O4/SiO2 hybrid presented a small decrease in relation to the ZnAl1.9Eu0.05O4 nanoparticles. This decrease was almost insignificant in relation to the benefits of silanization caused by the introduction of functional groups that promote combination of hybrid ZnAl1.9Eu0.05O4/SiO2 with biomolecules, being this promising for application as a biosensor used in the biomedical field for the diagnosis and treatment of diseases.
Keywords:
surface modification; biosensor; biological conjugation; luminescence
