Preparation of Basic Fuchsin Modified Magnetic Microspheres and Its Application in Isolation of Mycobacterium

Two kinds of methods were used to prepare basic fuchsin(BF) modified magnetic nanoparticles. The obtained BF modified nanoparticles (MNP-1 and MNP-2) were characterized using transmission electron microscope(TEM) and Fourier transformation infrared(FTIR) spectroscopy before used to adsorb mycobacterium from Staphylococcus aureus and Escherichia coli(E. coli). The effects of pH, adsorption time, concentration of bacteria, temperature, ionic strength and adsorbent dosage on the adsorption of bacterium were studied. The results show that both MNP-1 and MNP-2 have good selectivity for mycobacterium, and can be easily separated by external magnetic field. Under the optimized conditions, the highest adsorption rate for mycobacteria were 65% (MNP-1) and 85% (MNP-2), while only 20% of Staphylococcus aureus and 10% of E. coli can be adsorbed under the same conditions. The adsorption capacity of MNP-1 and MNP-2 for mycobacteria was 1. 48x10(10) and 3. 25x10(10) cfu/g, respectively.