An Experimental Study on capacitive touch sensor´s response to E. coli bacteria

Escherichia coli or E. coli is the dominant pathogen in Urinary Tract Infections (UTIs) in more than 80 % of the cases. Laboratory urine culture is the standard detection method which is expensive and time consuming. This paper studies the possibility of using a capacitive sensor to diagnose UTIs. Experimental tests were carried out to investigate the touch sensor´s response to artificially prepared E.coli sample. The capacitive touch sensor gave a consistent result that could be used to design a portable diagnostic device for early detection of UTIs. An exponential response was observed to increasing volume (up to 100 microliter) and E.coli presence in the sample. When the volume reached 100 microliter, the capacitance in average RAW Count Difference value became constant. Urine sample mixed with liquid E. coli gave the highest capacitance change (in average RAW Count Difference value) and the sensitivity at 100 microliter was found to be 22 counts per picofarad (pF).