Table 1. Zeta potential values of the SPIONs determined before and after incubation with the biofilm.

Samples	ζ potential (mV) before incubation with biofilm	ζ potential (mV) following incubation with biofilm
Bare SPIONs	5.9 ± 0.5	-17.2 ± 0.7
Amino functionalized SPIONs	22.2 ± 0.3	-15 ± 0.5
Carboxyl functionalized SPIONs	-20.1 ± 0.4	-16.9 ± 0.6