title: Hierarchical nanotextured microelectrodes overcome the molecular transport barrier to achieve rapid, direct bacterial detection.
abstract: Detection of biomolecules at low abundances is crucial to the rapid diagnosis of disease. Impressive sensitivities, typically measured with small model analytes, have been obtained with a variety of nano- and microscale sensors. A remaining challenge, however, is the rapid detection of large native biomolecules in real biological samples. Here we develop and investigate a sensor system that directly addresses the source of this challenge: the slow diffusion of large biomolecules traveling through solution to fixed sensors, and inefficient complexation of target molecules with immobilized probes. We engineer arrayed sensors on two distinct length scales: a ∼100 μm length scale commensurable with the distance bacterial mRNA can travel in the 30 min sample-to-answer duration urgently required in point-of-need diagnostic applications; and the nanometer length scale we prove necessary for efficient target capture. We challenge the specificity of our hierarchical nanotextured microsensors using crude bacterial lysates and document the first electronic chip to sense trace levels of bacteria in under 30 min.
authors.affiliation: Department of Electrical and Computer Engineering, Faculty of Engineering, Medicine, University of Toronto, Ontario, Canada.
authors.forename: Leyla
authors.initials: L
authors.lastname: Soleymani
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Fang
authors.forename: Brian
authors.initials: B
authors.lastname: Lam
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Bin
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Vasilyeva
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Ross
authors.forename: Edward H
authors.initials: EH
authors.lastname: Sargent
authors.forename: Shana O
authors.initials: SO
authors.lastname: Kelley
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D008839:Microelectrodes; D036103:Nanotechnology; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D012329:RNA, Bacterial; D012333:RNA, Messenger