Bacteria Growth Monitoring Through a Differential CMOS Capacitive Sensor

In this paper, we present a bacteria growth monitoring technique using a complementary metal-oxide semiconductor capacitive sensor. The proposed platform features a differential capacitive readout architecture with two interdigitized reference and sensing electrodes. These electrodes are exposed to pure Luria-Bertani (LB) medium and Escherichia Coli (E. Coli) bacteria suspended in the LB medium, respectively. In order to direct the solutions toward the electrodes, two microfluidic channels are implemented atop the electrodes through a direct-write assembly technique. We thereafter demonstrate and discuss the experimental results by using two different bacteria concentrations in the order of 10⁶ and 10⁷ per 1 mL in the LB medium.

I Introduction

Cmos-Based capacitive sensors have recently attracted the attention of several laboratory-on-chip (LoC) applications, such as DNA detection [1]; virus recognition [2]; cancer tracking [3]; cell localization [4]; chemical sensors [5]; and bacteria growth monitoring (BGM) [6]. The later is the focus of this paper. The growth of bacteria is recognized as an important factor in the early phase of diseases resulting from microbial contaminations [7]. To date, several techniques have been proposed to reveal bacterial contaminations in water, food, and blood using optical and electrical devices [8].