Mesoporous nanospheres functionalized optical microfiber biosensor for low concentration neurotransmitter detection.

A label-free and ultrasensitive microfiber interferometer biosensor has been demonstrated for detection of neurotransmitter molecule (5-HT). The surface morphology of the silicon dioxide nanospheres acting as molecule sieve provides an effective mean of gathering 5-HT molecules by designed mesoporous structure. The slight concentration change of 5-HT molecules is translated into a dramatic wavelength shift of the interferometric fringe pattern. The experimental results show that the biosensor has a linear response in concentration range from 100 fM to 1 µM and a detection limit as low as 84 fM.