Ultra-sensitive microfibre absorption detection in a microfluidic chip.

Zhang, Lei; Wang, Pan; Xiao, Yao; Yu, Huakang; Tong, Limin · Lab Chip · 2011

basic_science · Level V

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Abstract

We report a microfibre absorption sensor by using a 900 nm diameter silica microfibre embedded in a 125 μm wide microchannel with a detection length of 2.5 cm. Investigated by measuring the absorbance of methylene blue (MB), the sensor shows a detection limit down to 50 pM with excellent reversibility in a concentration range of 0-5 nM. The sensor has also been applied to bovine serum albumin (BSA) measurement, with a detection limit of 10 fg mL(-1). In addition, the sample volume requirement is merely 500 nL with a probing light power of about 150 nW, which is very promising for safe detection of single or a few molecules of biological specimens.