Microfluidic diagnostic systems for the rapid detection and quantification of pathogens

Abstract

This article reviews past and current research directed towards developing microfluidic systems that are able to rapidly detect the presence of pathogens and provide additional clinically relevant information about them (e.g., their antibiotic susceptibility, etc.) about them. It is estimated that pathogens are directly responsible for 15 million deaths worldwide annually. Many of these deaths could be prevented as a result of rapid and/or point-of-care diagnosis. The microfluidic systems reviewed here , which are in use and under development, seek to fulfill this significant need. The technical objective of these systems is to detect and estimate the concentration of pathogens of interest within clinical samples. This can be achieved by the detection and quantification of any of the following: (a) whole pathogen cells; (b) metabolites released or consumed by the pathogen; and (c) proteins or nucleic acid sequences that are specific to the pathogen of interest. The type of target assayed forms the basis behind the classification of the wide varieties of microfluidic systems encountered. However, irrespective of the actual target assayed for, the microfluidic systems have to overcome twin problems: that of low pathogen concentration and/or the presence of interferents. Hence various strategies, such as culturing, filtration, electro-kinetic separation, magnetic separation, enzyme linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), etc., are used to amplify and/or isolate the target pathogen prior to detection. Detection is accomplished using optical, electrical and mechanical techniques (or a combination of them). In this review, attempts have been made to highlight how the physics at the micro-scale has influenced the design of the separation and detection schemes employed. © 2008 Springer Science+Business Media, LLC.