In-situ DNA hybridization detection with a reflective microfiber grating biosensor

Abstract

A label-free fiber-optic biosensor with a reflective microfiber Bragg grating (mFBG) configuration for in-situ DNA hybridization detection has been proposed and experimentally demonstrated. A single straight Bragg grating inscribed in the silica microfiber provides two well-defined resonances in reflection, which show different response to external medium refractive index (RI) and present the same temperature sensitivity. By monitoring the wavelength separation between these two resonances, temperature-compensated RI measurement has been achieved. The label-free bio-recognition scheme used demonstrates that the sensor relies on the surface functionalization of a monolayer of poly-l-lysine (PLL), synthetic DNA sequences that bind with high specificity to a given target. In addition to monitoring the surface functionalization of the fiber in real-time, the results also show how the fiber biosensor can detect the presence of the DNA hybridization with high specificity, in various concentration of target DNA solutions, with lowest detectable concentration of 0.5 µM.

Oligonucleotide-Hybridization Fiber-Optic Biosensor Using a Narrow Bandwidth Long Period Grating

“…LPGs are simple, robust photonic devices when compared with the other approaches we mentioned before, which are based on a few microns in diameter fibers [4][5][6][7]. The unusual narrow bandwidth of the LPGs we present here allows improving the detection limit of this biosensor when compared to dual-peak ere L is the l iods [11].…”

“…Within the applications of fiber-optic biosensors, the detection of DNA hybridization is of much interest, due to their specific capability to detect particular DNA sequences that might be of interest for environmental, biological or health applications, epidemic controls, diagnosis, drug research, etc. Several approaches have been reported up to date to measure the DNA-hybridization based on different photonic devices, as for example micro-fiber gratings [4], gold-coated microtapers [5], surface plasmon resonances based sensors [6], microwave photonic filters [7] or dual-peak Long Period Gratings (LPGs) [8]. Other sensors based on waveguides with strong evanescent fields show also high potential as, for example, reverse symmetry waveguides [9,10].…”

EDC-Mediated Oligonucleotide Immobilization on a Long Period Grating Optical Biosensor

“…However, the measurement time could easily be reduced to 1 scan/s and the resulting data used to give kinetic analyses of initial rates of binding. Finally, if the noise effect could be eliminated effectively by using an optical interrogation system with 1 pm resolution, this would theoretically lead to a detection sensitivity of 4 nM oligonucleotide concentration, which would be two orders of magnitude lower than the microfiber Bragg grating based DNA biosensor reported previously [12].…”

“…The most important advantages of this biosensor platform are that it is able to provide biosensing with unique features of label-free, real-time, multiplex, and in-line determination. Various fiber optic biosensors have been presented by employing long period gratings (LPGs) [7,8], tilted fiber gratings (TFGs) [9][10][11] micro fiber Bragg gratings (mFBGs) [12] LPGs in photonic crystal fibers [13] and surface plasmon resonance (SPR) [14].…”

“…Hence, biosensors based on dLPGs should achieve comparable or better performances with respect to the standard LPG or mFBG based biosensors [12,31].…”