Detection method and detection system using local surface plasmon resonance (LSPR) spectral image brightness contrast
A detection method and a detection system for detecting objects of interest attached to a surface of a plurality of reporters, wherein the plurality of reporters are flowing in a microfluidic chip and illuminated by a light source. The detection method has following steps: obtaining a plurality of local surface plasmon resonance (LSPR) spectral images of each the plurality of the reporters individually, wherein each of the LSPR spectral images has a brightness of a long wavelength band (B A ) and a brightness of a short wavelength band (B B ); calculating a spectral image brightness contrast γ for each of the LSPR spectral images, wherein γ = B A - B B B A + B B ; and, defining a positive threshold for |γ|≥0.1.
1 . A detection method for detecting objects of interest attached to a surface of a plurality of reporters, comprising:
illuminating, by a light source, the plurality of reporters flowing in a microfluidic chip;
obtaining, by an image sensor, a plurality of local surface plasmon resonance (LSPR) spectral images of each of the plurality of the reporters individually, wherein each of the LSPR spectral images has a brightness of a long wavelength band (B A ) and a brightness of a short wavelength band (B B );
calculating, by a processor, a spectral image brightness contrast y for each of the reporters to amplify a spectral shift caused by the reporters and thereby enhance detection sensitivity, wherein γ=(B A −B B )/(B A +B B );
calculating, by a processor, an absolute value |γ| of each of the spectral image brightness contrast γ; and
determining, by a processor, whether each of absolute value |γ| satisfies a defined positive threshold for |γ|>0.1.
2 . The detection method as claimed in claim 1 , wherein when a molecular weight of the objects of interest is larger than 10 kDa, the positive threshold is γ>0.1.
3 . The detection method as claimed in claim 1 , wherein when a molecular weight of the objects of interest is less than 500 Da, the positive threshold is −y>0.1.
4 . The detection method as claimed in claim 1 , wherein the long wavelength band and the short wavelength band are divided by a peak of a LSPR spectral image of the reporter before being shifted.
5 . The detection method as claimed in claim 4 , wherein the peak of a LSPR spectral image of the reporter before being shifted is X nm, the long wavelength band is defined as (X+10)=10; the short wavelength band is defined as (X-10)=10.
6 . The detection method as claimed in claim 1 , wherein before defining the positive threshold, the method further comprising: defining a diagram of each of the spectral image brightness contrast y and a counting number of the reporters corresponding to each of the spectral image brightness contrast y.
7 . The detection method as claimed in claim 1 , wherein the objects of interest attached to the surface of a plurality of reporters vis a plurality of immuno-agents, and a concentration of the plurality of immuno-agents is 20%.
8 . The detection method as claimed in claim 7 , wherein the light source is a dark-field illumination system.
9 . A detection system for detecting objects of interest attached to a surface of a plurality of reporters, comprising:
a light source for illuminating the plurality of reporters flowing in a microfluidic chip;
an image capture device, electrically connected to the image capture device, configured for obtaining a plurality of local surface plasmon resonance (LSPR) spectral images of each the plurality of the reporters individually, wherein each of the LSPR spectral images has a brightness of a long wavelength band (B A ) and a brightness of a short wavelength band (B B );
a processor for calculating a spectral image brightness contrast y for each of the reporters to amplify a spectral shift caused by the reporters and thereby enhance detection sensitivity, wherein γ=(B A −B B )/(B A +B B ), calculating an absolute value |γ| of each of the spectral image brightness contrast γ, and then determining whether each of the absolute value |γ| satisfies defining a defined positive threshold for |γ|>0.1.
10 . The detection system as claimed in claim 9 , wherein when a molecular weight of the objects of interest is larger than 10 kDa, the positive threshold is γ=0.1.
11 . The detection system as claimed in claim 9 , wherein when a molecular weight of the objects of interest is smaller than 500 Da, the positive threshold is −y>0.1.
12 . The detection system as claimed in claim 9 , wherein the long wavelength band and the short wavelength band are divided by a peak of a LSPR spectral image of the reporter before being shifted.
13 . The detection system as claimed in claim 12 , wherein the peak of a LSPR spectral image of the reporter before being shifted is X nm, the long wavelength band is defined as (X+10)±10; the short wavelength band is defined as (X−10)±10.
14 . The detection system as claimed in claim 9 , wherein before defining the positive threshold, the method further comprising:
defining a diagram of each of the spectral image brightness contrast y and a counting number of the reporters corresponding to each of the spectral image brightness contrast y.
15 . The detection system as claimed in claim 9 , the objects of interest attached to the surface of a plurality of reporters via a plurality of immuno-agents, and a concentration of the plurality of immuno-agents is 20%.
16 . The detection system as claimed in claim 15 , wherein the light source is a dark-field illumination system.
17 . The detection system as claimed in claim 9 , wherein the image capture device is a camera installed in a hand-held device.