RESUMO
The non-toxic CuFe2O4 magnetic nanoparticles have been solvothermally synthesized, characterized and used as an efficient magnetic precursor for papain immobilization and then investigated antibacterial properties of them. For increasing the antibacterial activity, the silver nanoparticles were doped on CuFe2O4 magnetic nanoparticles. All prepared samples exhibited stronger antibacterial properties against Gram-positive bacteria (Staphyloccocus aureus) than Gram-negative bacteria (Escherichia coli). However, it was determined that the Ag/CuFe2O4 had a more vigorous antibacterial property against the Staphyloccocus aureus bacteria by calculating the inhibition diameter of 25⯱â¯0.1â¯mm in the synthesized samples. Also, the antibacterial activity increased by immobilization of papain.
Assuntos
Cobre/química , Enzimas Imobilizadas , Compostos Férricos/química , Nanopartículas de Magnetita/química , Papaína/farmacologia , Prata/química , Taninos/química , Antibacterianos/química , Antibacterianos/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Ativação Enzimática , Concentração de Íons de Hidrogênio , Cinética , Nanopartículas de Magnetita/ultraestrutura , Papaína/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Temperatura , Termogravimetria , Difração de Raios XRESUMO
This article presents a study of glucose oxidase (GOx) immobilization by employing tannic acid (TA) modified-CoFe2O4 (CFO) magnetic nanoparticles which demonstrates novel aspect for enzyme immobilization. By using the strong protein and tannic acid binding, GOx immobilization was carried out via physical adsorption in a simpler way compared with the other immobilization methods which require various chemicals and complicated procedures which is difficult, expensive, time-consuming, and destructive to the enzyme structure. CFO was synthesized by hydrothermal synthesis and modified with TA to immobilize GOx. The immobilized GOx demonstrated maximum catalytic activity at pH 6.5 and 45 °C. The samples were characterized by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, and fourier transform infrared spectroscopy (FTIR), all of which confirm the surface modification of CFO and GOx immobilization. Also, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were performed to demonstrate the surface morphology and chemical structure of samples. According to the Lineweaver-Burk plot, GOx possessed lower affinity to glucose after immobilization, and the Michelis-Menten constant (KM) of immobilized and free GOx were found to be 50.05 mM and 28.00 mM, respectively. The immobilized GOx showed excellent reusability, and even after 8 consecutive activity assay runs, the immobilized GOx maintained ca. 60% of its initial activity.
