Filter-based microfluidic device as a platform for immunofluorescent assay of microbial cells.
A filter-based microfluidic device was combined with immunofluorescent labeling as a platform to rapidly detect microbial cells. The coin-sized device consisted of micro-chambers, micro-channels and filter weirs (gap = 1-2 microm), and was demonstrated to effectively trap and concentrate microbial cells (i.e., Cryptosporidium parvum and Giardia lamblia), which were larger in size than the weir gap. After sample injection, a staining solution containing fluorescently-labeled antibodies was continuously provided into the device (flow rate = 20 microl min(-1)) to flush the microbial cells toward the weirs and to accelerate the fluorescent labeling reaction. Using a staining solution that was 10 to 100 times more dilute than the recommended concentration used in a conventional glass method, those target cells with a fluorescent signal-to-noise ratio of 12 could be microscopically observed at single-cell level within 2 to 5 min prior to secondary washing.
Department of Civil Engineering, National University of Singapore, Singapore 117576, Republic of Singapore.
Liang
L
Zhu
Qing
Q
Zhang
Hanhua
H
Feng
Simon
S
Ang
Fook Siong
FS
Chau
Wen-Tso
WT
Liu
D000818:Animals; D016785:Cryptosporidium parvum / Q000166:cytology / Q000276:immunology / Q000302:isolation & purification*; D005374:Filtration / Q000295:instrumentation; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D015200:Fluoroimmunoassay / Q000379:methods; D016829:Giardia lamblia / Q000166:cytology / Q000276:immunology / Q000302:isolation & purification*; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods*