Study on the Mutagenic Properties of Mutagen Using Piezoelectric Impedance Microbial Sensing

The characteristics of mutagenic growth of Salmonella trphimurium strain TA100 induced by sodium azide were investigated by piezoelectric impedance microbial sensing. The variation of motional resistance (ΔR₁) versus time curves during the growth of revertants in the presence/absence of NaN₃ were measured and discussed. Compared to the growth process in the absence of NaN₃, a larger ΔR₁ value was obtained after addition of NaN₃, which indicates that part of the TA100 strain recovers its growth ability due to the mutagenic property of NaN₃. Moreover, the signal size of ΔR₁ increased with the increase of NaN₃ dosage within a certain dosage range, and decreased when a higher dosage of sodium azide was used. Finally, the following new impedance response equation containing the mutagenic intensity coefficient (a) and poisonous/inhibitory intensity coefficient (b) was obtained: where the a and b values of NaN₃ were 0.6063 and 1.1998 × 10⁻³, respectively. The satisfactory value of q_r shows that this equation was suitable to reflect the effect of the properties of mutagen on microorganisms.