National Research Council of Canada. Measurement Science and Standards
signal amplification; lab-on-a-chip; microfluidic device; dendrimer; aptamer; AFM
The majority of foodborne illnesses and deaths are caused by pathogenic bacteria. Therefore there is an increasingly urgent need for rapid, sensitive and cost-effective detection methods in order to avoid or to respond to outbreaks of such diseases in a timely manner. In an attempt to develop a simple and sensitive fluorescence intensity based microfluidic detection platform, PAMAM dendrimer was immobilized onto PDMS microchannel that was further modified with DNA aptamers for detections of E. coli O157:H7 cells. To further improve detection performance, rolling circle amplification (RCA) was employed to enhance the fluorescence signals. In addition, RCA products were characterized by both agarose gel electrophoresis and atomic force microscopy. Our results showed that RCA was able to enhance detection signals by up to 50 times and that the limit of detection of the system was reduced to 102 cells/mL with excellent detection specificities. Therefore, it can be concluded that this simple dendrimer-aptamer based microfluidic detection platform with RCA signal enhancement is a promising method for rapid and sensitive detection for foodborne pathogenic bacteria.