Cells-on-chip based transducer platform for probing toxicity of metal nanoparticles

In this work, we developed a cells-on-chip based transducer (CoCT) platform for probing toxicity of silver nanoparticles (Ag NPs) using non-Faradaic electrochemical impedance spectroscopy (nFEIS). This transducing platform was consists of arrays of capacitor on chip in which each capacitor was functionalized with living Escherichia coli cells. These cells were capable of responding to exposure of different size and concentration of Ag NPs. The capacitive response of CoCT was dependent on size and concentration of NPs. E. coli cells-on-chip response exhibited dramatic loss of capacitance and showed that maximum toxicity to cells-on-chip occurred with smaller 10 nm sized Ag NPs compared to larger size of 100 nm NPs. The cells tend to resist to the larger 100 nm size of NPs that did not affect the cells-on-chip. Our results demonstrated that whole-cell biosensor chip response at a particular frequency enabled determining the severity of the stress imposed by smaller size of Ag NPs. Further, our results were validated through fourier transform infrared spectroscopy (FTIR) and growth of cell/cellular debris and also determined the NPs stress induced toxicity in cells as a proof-of-concept. The methodology developed in this study potentially be extended to other nanomaterials (NMs) for classifying toxic from non-toxic NMs.