Droplet-based Impedance Sensing for Biomedical Applications and Probing Bacterial Response to Environmental Stressors

SeyedehAida Ebrahimi, Purdue University


According to the World Health Organization, every year around 60 million people die because of cardiovascular diseases, cancer, diabetes, and infectious diseases (including HIV, Tuberculosis, and foodborne illnesses). The majority of people dying of these health conditions live in low- to mid-income countries with less access to advanced medical diagnostic tools. Low-cost, portable biosensors can offer unprecedented opportunities for realization of point-of-care diagnostics that are accessible to a broader population. In addition, among the grand challenges of the 21st century, the antibiotic-resistance of pathogenic bacteria poses a serious threat to the global health. Rapid detection of bacteria and subsequent prescription of the required dosage of antibiotics are critical for timely treatment of bacterial infections and slow down the emergence of antibiotic resistance. Conventional antibacterial testing systems are usually slow or expensive. Therefore, faster and more accessible methods are highly desirable. To approach both problems, we need to develop low-cost, rapid bioanalysis tools that are also accurate and allow multiplexed screening. Towards this goal, we developed a low-cost, array-formatted electrochemical sensor for rapid detection and on-chip analysis of biomolecules, including DNA and bacteria. The method utilizes droplet evaporation to concentrate the analyte and reduces the detection time from days to mere minutes. We conducted a comprehensive analysis of different parameters affecting the sensor performance, all supported by a physics-based framework. This work demonstrates the power of time-dependent electrical analysis to sort live and dead bacterial cells in only a few minutes as well as on-chip probing of some of their fundamental behaviors in response to important environmental triggers, in particular, osmotic stress, heat, and antibiotics. These findings highlight the potential of electrochemical biosensors which in tandem with the advances in microfluidics and material processing can create next generation of low-cost, real-time biological interrogation systems.




Alam, Purdue University.

Subject Area

Biomedical engineering|Electrical engineering

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