Investigation of magnetic microdiscs for bacterial pathogen detection

Keisha Y. Castillo-Torres; Nicolas Garraud; David P. Arnold; Eric S. McLamore

doi:10.1117/12.2228610

13 May 2016 Investigation of magnetic microdiscs for bacterial pathogen detection

Keisha Y. Castillo-Torres, Nicolas Garraud, David P. Arnold, Eric S. McLamore

Proceedings Volume 9863, Smart Biomedical and Physiological Sensor Technology XIII; 98630G (2016) https://doi.org/10.1117/12.2228610
Event: SPIE Commercial + Scientific Sensing and Imaging, 2016, Baltimore, MD, United States

Abstract

Despite strict regulations to control the presence of human pathogens in our food supply, recent foodborne outbreaks have heightened public concern about food safety and created urgency to improve methods for pathogen detection. Herein we explore a potentially portable, low-cost system that uses magnetic microdiscs for the detection of bacterial pathogens in liquid samples. The system operates by optically measuring the rotational dynamics of suspended magnetic microdiscs functionalized with pathogen-binding aptamers. The soft ferromagnetic (Ni₈₀Fe₂₀) microdiscs exhibit a closed magnetic spin arrangement (i.e. spin vortex) with zero magnetic stray field, leading to no disc agglomeration when in free suspension. With very high surface area for functionalization and volumes 10,000x larger than commonly used superparamagnetic nanoparticles, these 1.5-μm-diameter microdiscs are well suited for tagging, trapping, actuating, or interrogating bacterial targets. This work reports a wafer-level microfabrication process for fabrication of 600 million magnetic microdiscs per substrate and measurement of their rotational dynamics response. Additionally, the biofunctionalization of the microdiscs with DNA aptamers, subsequent binding to E. coli bacteria, and their magnetic manipulation is reported.

Citation Download Citation

Keisha Y. Castillo-Torres, Nicolas Garraud, David P. Arnold, and Eric S. McLamore "Investigation of magnetic microdiscs for bacterial pathogen detection", Proc. SPIE 9863, Smart Biomedical and Physiological Sensor Technology XIII, 98630G (13 May 2016); https://doi.org/10.1117/12.2228610

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