A replaceable liposomal aptamer for the ultrasensitive and rapid detection of biotin

Tzu Cheng Sung, Wen Yih Chen, Pramod Shah, Chien Sheng Chen

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Biotin is an essential vitamin which plays an important role for maintaining normal physiological function. A rapid, sensitive, and simple method is necessary to monitor the biotin level. Here, we reported a replacement assay for the detection of biotin using a replaceable liposomal aptamer. Replacement assay is a competitive assay where a sample analyte replaces the labeled competitor of analyte out of its biorecognition element on a surface. It is user friendly and time-saving because of washing free. We used aptamer as a competitor, not a biorecognition element as tradition. To label aptamers, we used cholesterol-conjugated aptamers to tag signal-amplifying-liposomes. Without the need of conjugation procedure, aptamers can be easily incorporated into the surface of dye-encapsulating liposomes. Two aptamers as competitors of biotin, ST-21 and ST-21M with different affinities to streptavidin, were studied in parallel for the detection of biotin using replacement assays. ST-21 and ST-21M aptamers reached to limits of detection of 1.32 pg/80 μl and 0.47 pg/80 μl, respectively. The dynamic ranges of our assays using ST-21 and ST-21M aptamers were seven and four orders of magnitude, respectively. This assay can be completed in 20 minutes without washing steps. These results were overall better than previous reported assays.

Original languageEnglish
Article number21369
JournalScientific Reports
StatePublished - 23 Feb 2016


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