Label-free oligonucleotide biosensor based on dual-peak long period fiber grating
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Cardoso, Marcos R.
Mendonça, Cleber R.
Nagel, David A.
Hine, Anna V.
We report the simplification and development of biofunctionalization methodology based on one-step 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)-mediated reaction. The dual-peak long period grating (dLPG) has been demonstrated its inherent ultrahigh sensitivity to refractive index (RI), achieving 50-fold improvement in RI sensitivity over a standard LPG sensor used in low RI range. With the simple and efficient immobilization of unmodified oligonucleotides on sensor surface, dLPG-based biosensor has been used to monitor the hybridization of complementary oligonucleotides showing a detectable oligonucleotide concentration of 4 nM with the advantages of label-free, real-time, and ultrahigh sensitivity.