A fluorescent biosensor and detection method based on coupled grating

Abstract

The invention discloses a coupling grating-based fluorescent biosensor and a detection method thereof. A silicon base is arranged at the bottom of a substrate; a transmission waveguide is connected to one end of a coupling grating structure; the transmission waveguide and the coupling grating structure are arranged at the top of the substrate separately; an upper wrapping layer coats the top of the substrate; a microflow channel is arranged at the top of the upper wrapping layer; a sensing area for detection is arranged between the microflow channel and the upper wrapping layer; the sensing area is located at the position of an emission part of a coupling grating; a modified modifying ligand layer is arranged in the sensing area; the end surface of a multi-mode fiber is obliquely arranged in the microflow channel; and the end surface of the multi-mode fiber is located above the coupling grating structure. By using the coupling grating structure, the complexity of an excitation light source and a light path design thereof is reduced, so that the cost is reduced, the period of the grating is adjusted, emitted light is within a certain dip angle range and the interference of background light is effectively reduced.

Description

technical field [0001] The invention relates to a biochemical detection and integrated photonic chip, in particular to a fluorescent biosensor based on a coupled grating and a detection method. Background technique [0002] Biosensor has become a very important research direction in the field of analytical chemistry and biochemistry, and people have made extensive research on it. Fluorescent biosensing relies on fluorescent signals as the means of detection. The detection of fluorescent substances usually relies on the enhancement, quenching or shifting of the emission wavelength to obtain the transformation of the fluorescent signal. The signal is converted into a fluorescent signal to realize the analysis of the target. Because the fluorescence detection method is easy to operate, convenient and fast, and can also realize online real-time analysis, it has been widely used in daily analysis and detection. At the same time, due to its high sensitivity and the fluorescence ...

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Problems solved by technology

[0004] Currently integrated photonics biosensing scheme, Adam L.Washburn.etc, "Label-FreeQuantitation of a Cancer Biomarker in Complex Media Using Silicon PhotonicMicroring Resonators", using silicon photonic microresonators in complex media as Label-Free quantitative Cancer biomarkers, Anal.Chem.2009, 81, 9499-9506, Enrique Valera.etc, "Development and validation of an immunosensor for monocyte chemotactic protein 1 using asilicon photonic microring resonator biosensing platform" a silicon photonic microresonator to The platform for developing and verifying monocyte chemoattractant proteins of immunosensors, Clinical Biochemistry, 2015, 49(1): 121-126, is mostly based on the principle of evanescent wave detection, and the general process is first in the waveguide in the sensing area of ​​the optical device The surface uses chemical methods to modify the upper layer of acceptor substances. When the waveguide is in a sample with the corresponding ligand, the ligand and the acceptor will specifically bind, affecting the evanescent wave of light transmitted in the waveguide, thereby It causes the phase change of the transmission signal, and the phase change realizes the intensity change through the interference principle, so as to be detected, but for the detection of small molecules and ultra-low concentrations, this sensing method does not work well. In addition, Since the materials of photonic devices are mostly inorganic materials (silicon, silicon nitride), the biological modification process is relatively complicated, and the stability and repeatability are poor.

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