Optical biosensor for biomolecular interaction analysis

A measuring device for biomolecular interaction analysis, said device comprising:

• an optical biosensor having a surface of which optical characteristics are changed with adsorption of a substance onto the surface;
• and
• an optical measuring device for measuring the optical characteristics of the surface of said optical biosensor, said optical measuring device being arranged to receive light of multiple wavelengths from the surface of said optical biosensor, determine absorbance changes at the multiple wavelengths, and remove noise from the optical characteristic measurement,
• wherein said optical measuring device is arranged to measure the intensity of light outputted from said optical biosensor in a second band including a maximum absorption wavelength, a first band covering a longer wavelength range than the maximum absorption wavelength, and a third band covering a shorter wavelength range than the maximum absorption wavelength,
• and wherein the measuring device further comprises:
• a first optical sensor element for measuring an intensity of light in said first band;
• a second optical sensor element for measuring an intensity of light in said second band;
• a third optical sensor element for measuring an intensity of light in said third band;
• and
• a data processing unit for calculating absorbance A(λ1), A(λ2), and A(λ3) in said first band, said second band, and said third band, respectively, from intensity of lights measured by said first optical sensor element, said second optical sensor element, and said third optical sensor element on the basis of the following formula (1),
• A(λ)=−log [L(λ)/{R(λ)−d(λ)}] (1),
• λ representing wavelength bands of said first wavelength band λ1, said second wavelength band λ2, and said third wavelength λ3, R(λ) representing an intensity of light measured by using a reference reflection plate having a known reflection, d(λ) representing an intensity of light measured without irradiating light, L(λ) representing an intensity of light measured by using said first optical sensor element, said second optical sensor element, and third optical sensor element, said data processing unit calculating changes of absorbance A(λ1) and A(λ3), calculating a binding signal U on the basis of following formula (3),
• U=ΔA(λ3)−KΔA(λ1) (3)
• ΔA(λ1) and ΔA(λ3) representing changes of absorbance A(λ1) and A(λ3), K representing changes of a constant for normalizing a change ΔA(λ) of peak absorbance.