Method for obtaining binding kinetic rate constants using fiber optic particle plasmon resonance (FOPPR) sensor

摘要

A method for obtaining the binding kinetic rate constants using fiber optic particle plasmon resonance (FOPPR) sensor, suitable for a test solution with two or more concentrations, which employs the following major steps: providing one FOPPR sensor instrument system, obtaining optical time-resolved signal intensities starting at the initial time to the steady state of the two or more regions, substituting the measured signal intensity values into the formula which is derived by using the pseudo-first order rate equation model. In addition, this method measures the temporal signal intensity evolution under static conditions as the samples are quickly loaded. As a result, unlike the conventional device where the sample is continuously infused, the method is able to measure the association and dissociation rate constants of which the upper bounds are not limited by the sample flow rate.

主权项

1. A method for obtaining the binding kinetic rate constants using a fiber optic particle plasmon resonance (FOPPR) sensor, comprising the steps of:
providing a fiber optic particle plasmon resonance sensor, wherein the fiber optic particle plasmon resonance sensor at least comprises: a light source to emit a light beam; a photoreceiver; and a fiber sensor chip, wherein the fiber sensor chip is located between the light source and the photoreceiver and the fiber sensor chip comprises: an optical fiber, wherein the optical fiber comprises a first region and a second region; the first region is located at two corresponding sides of the second region, wherein the first region comprises a fiber core, a cladding, and a protective layer, the refractive index of the fiber core is greater than that of the cladding such that the light beam can propagate within the fiber core; and the second region comprises the fiber core, the cladding, a noble metal nanoparticle layer, and a bio-recognition layer; a first plate, wherein the first plate comprise a trench and the trench is used to place the optical fiber; and a second plate, wherein a first tube and second tube are vertically installed on one side of the second plate, the first tube is hollow and comprises a first opening, the second tube is hollow and comprises a second opening, the first tube and the second tube are connected to the second plate, the other side of the second plate which is opposite to the first plate is face-to-face against the side of the first plate containing the trench such that the optical fiber can be placed between the first plate and the second plate and into the trench within the first plate, and the second plate is placed face-to-face against the first plate to seal them off; allowing the light beam from the light source of the fiber optic particle plasmon resonance sensor to enter the fiber sensor chip and propagate within the fiber core due to total internal reflection, and let the photoreceiver of the fiber optic particle plasmon resonance sensor receive a light signal; quickly injecting a reference solution into the first opening of the first tube, wherein the first opening serves as a flow inlet; injecting N test solutions sequentially into the first opening of the first tube, such that each of the test solutions quickly flows onto the bio-recognition layer of the fiber sensor chip and remains in a static condition within the trench till the next injection, wherein each of the test solutions comprises a separate concentration C.sub.i, where an integer i is from 1 to N, and the number of N is equal to or greater than 2; converting, with the fiber optic particle plasmon resonance sensor, the light signals received by the photoreceiver into a time-resolved curve diagram of time-revolved light signal intensity, wherein the number of segments i in the curve of the curve diagram is the same as that of test solutions of concentration C.sub.i, and each segment numbered as i is corresponding to the time-resolved light signal intensity generated by each of the injected test solutions of concentration C, in sequence, respectively; obtaining each of the time-resolved light signal profiles starting at the initial time of the segments in the curve diagram I.sub.t, the time-revolved light signal intensity values of the segments at the steady states I.sub.eq, and the reference light signal intensity I.sub.0 corresponding to the average signal intensity level of the reference solution; obtaining the time-revolved light signal intensity values I.sub.t at the initial time when each of the test solutions has filled up the trench and remains at a static condition, taking I.sub.t into a formula [(I.sub.t−I.sub.eq)/(I.sub.0−I.sub.eq)] to calculate a plurality of logarithm values of the fraction formula, ln [(I.sub.t−I.sub.eq)/(I.sub.0−I.sub.eq)], when the reference light signal intensity prior to the initial time is not obtained using the reference solution (i.gtoreq.2), subtracting each logarithm value by ln [(I.sub.0−I.sub.eqi)/(I.sub.eqi(i−1)−I.sub.eqi)] to adjust the intercept of the linear formula as zero, and executing a linear regression by using the logarithm values versus time to obtain a plurality of linear line diagrams corresponding to the number of the segments; obtaining a slope S.sub.i of a linear line in the plurality of linear line diagrams; and using the concentrations C.sub.i and the corresponding slopes S.sub.i to execute another linear regression to obtain a slope and an intercept of each regression line, then taking the results into a concentration-versus-slope linear equation S(C.sub.i)=k.sub.aC.sub.i+k.sub.d to obtain an association constant k.sub.a and a dissociation constant k.sub.d.