Abstract
Dielectrophoresis (DEP) has emerged as a powerful, label-free method for selectively isolating viable pathogens. While traditional culture-based diagnostics remain the gold standard, they require 15-48 h and often lack specificity or efficiency compared to newer techniques. In this study, we developed a CMOS-compatible microfluidic-based DEP chip with 3-D nano-electrode arrays and adjustable electrode spacing. By optimizing key DEP parameters and testing in urine, we achieved up to 90 % capture efficiency in deionized water and up to 37 % capture efficiency in diluted urine. Our chip also reduced colony formation time by approximately 6 h, highlighting its potential to accelerate microbial diagnostics. This study presents a CMOS-based dielectrophoretic chip integrated with a microfluidic system. The effects of various parameters including voltage, frequency, flow rate, and waveform on bacterial capture efficiency were evaluated in diluted water and urine. Colony formation time was then compared between conventional agar culture and the chip-based capture-enrichment method to assess its diagnostic potential. We discovered that higher applied voltage increased capture efficiency, aligning with DEP theory. The optimal frequency for Escherichia coli (E. coli) was 3 MHz, while both lower and higher frequencies led to reduced efficiency. Increasing the flow rate also diminished capture performance. In urine, square wave input enhanced capture efficiency to 37 %. Furthermore, chip-based enrichment shortened colony formation time by approximately six hours compared to conventional agar culture. Our study systematically examined key parameters affecting E. coli capture using a CMOS-based DEP chip. Notably, our chip-based enrichment shortened visible colony formation time by approximately six hours compared to conventional culture methods. While most studies focus on simulations or parameter optimization, this work highlights diagnostic relevance by evaluating actual culture acceleration.