JPS6214779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the electrophoretic velocity of visible suspended particles, such as biological cells.

The above-mentioned measurement of the electrophoretic velocity of suspended particles in cells has a wide range of applications in biological research, clinical testing, etc., and various measuring devices have already been proposed. These devices focus images of suspended particles on a grating and measure the light transmitted through the grating behind the grating. The photometric output from the particle images changes in an alternating current manner, and the frequency corresponds to the electrophoretic speed of the suspended particles. Therefore, various calculations can be performed from the photometric output, which is the superimposition of alternating current signals of various frequencies due to a large number of suspended particle images. The electrophoretic velocity distribution of a large number of suspended particles can be determined using this method. However, in order to obtain stable measurement results with these conventional devices, a particle suspension liquid of a relatively high concentration is required. For example, consider the following extreme case. If there are only two suspended particles and both images overlap the grid lines at the same time and appear between the grid lines, the AC components of the photometric output from the two suspended particles will overlap in phase, so the AC output will be 2.
becomes. On the other hand, if two particle images, one of which overlaps the grid lines, and the other are located between the grid lines, the two AC signals will overlap with opposite phases in the photometric output, so the AC output will be 0. In reality, the electrophoretic speeds of two particles are rarely exactly the same, and the phase relationship between them is never as extreme as the one above, so the probability that the above situation will occur is small. However, as the number of particles increases, the number of pairs of particles with the same velocity increases. Cases in which they cancel each other out occur relatively often, and instability appears in which the electrophoretic velocity distribution diagram becomes relatively sharp or broad with each measurement even though the samples are from the same group. The average event in which the alternating current components originating from individual particles mutually strengthen and cancel each other accounts for most of the possible events, and it takes a considerable amount of time to eliminate fluctuations in the measurement results each time. A large number of particles are required.

However, the fact that only a small number of particles are required for measurement is an advantage in measurement, especially when using a special antibody as a reagent for biological samples.
When processing a large number of samples, it is very important that only a small number of cells are required for measurement in each individual sample.

The present invention was made with the object of providing an apparatus capable of stably measuring the electrophoretic velocity of suspended particles using a relatively small number of particles. The electrophoresis measuring device according to the present invention arranges a plurality of light receiving elements parallel to the direction of electrophoresis of floating particles, forms an image of the floating particles on the array surface of the light receiving elements, and forms a particle image on the light receiving surface of each light receiving element. The particle transit time is measured and the time distribution is displayed, and the concentration of suspended particles is such that an image of one particle is projected at a time from every other light-receiving element. . The width of each photodetector is 1 mm, the projection magnification is 10x, and the depth of focus is
If it is 0.5 mm, a particle concentration of about 50 particles/m ³ is sufficient. The present invention will be explained below with reference to Examples.

FIG. 1 shows an embodiment of the present invention. 1 is an electrophoresis tube filled with a solution in which visible particles are suspended, electrodes are inserted at both ends (not shown), and the particles are electrophoresed in the direction of the arrow. The electrophoresis tube is strongly illuminated from beyond the plane of the figure. 2 forms an image of the particles that are strongly illuminated by a lens on the light receiving element surface 3. P1 to Pn are light receiving elements, and in this embodiment, there are a total of 32 light receiving elements, and they are arranged in a row, and the total length of one example is 30 mm. The light-receiving surface of each light-receiving element is a square with sides of less than 1 mm, and 32 light-receiving elements are housed in one package.
The arrangement direction of these light receiving elements is parallel to the tube axis of the electrophoresis tube 1. The lens 2 magnifies the image of the floating particles ten times and forms it on the light receiving surface 3. The outputs of the light receiving elements P1 to Pn are respectively input to the clock circuit 4. The clock circuit 4 outputs a signal corresponding to each light receiving element and inputs it to the data processing circuit 5, and the data processing circuit calculates the electrophoretic velocity distribution of the sample particles based on this input.

FIG. 2 shows the configuration of the clock circuit 4 described above. The output terminals of the respective light receiving elements P1 to Pn _-1 are connected to the (-) terminals of the corresponding comparators C1 to Cn _-1 , respectively. The output terminal of the light receiving element on the right side of the corresponding light receiving element is connected to the (+) terminal of each of the comparators C1 to Cn _-1 . The output terminal of each comparator C1 to Cn _-1 is connected to one input terminal of three-terminal AND gates A1 to An _-2 . An inverted signal of the output of the comparator on the right of the corresponding comparator is applied to the other input terminal of each AND gate. A clock pulse output from a pulse generator Cp is applied to the remaining input terminal of each AND gate. The outputs of the AND gates A1 to An _-2 are respectively input to counters K1 to Kn _-2 and counted.
The count outputs of the counters K1 to Kn _-2 are input to the data processing circuit 5.

The operation of the clock circuit 4 will be explained. For example, let us now focus on the light receiving element P2 and assume that an image of one particle is formed on P2. The image is assumed to move from left to right in Figure 2. It is assumed that the (-) terminal input of the comparator C2 is at a high level while the image is being projected onto P2, and no particle images are formed on the left and right neighbors P1 and P3. Then, the (-) terminal input of comparator C2 is high and the (+) terminal input is low.
The output of 2 is low. Further, since the (-) terminal input of the comparator C1 is low and the (+) terminal input is high, the output of C1 is high. Therefore, the two input terminals on the right side of AND gate A1 are both high, and A1 is open, and the pulse generator
The output pulses of Cp are input to counter K1 and counted. This counting continues until the particle image finishes passing through the light receiving element P2. Therefore, the final count output of the counter K1 is that one particle image is detected by the light receiving element P2.
represents the time required to cross the The data processing device 5 repeatedly scans and monitors the outputs of the counters K1 to Kn _-2 and the outputs of the comparators C2 to Cn _-1 . For example, for counter K1, while the output of comparator P2 is low, K1 When it detects that the output of P2 is high without reading the output of P2, it reads the output of K1 and resets K1. In the data processing device, the count value of each counter read in this way is used as the address designation value of the memory, and the number 1 is added to the designated address of the memory. That is, 1 is added to the position of the measured particle velocity on the memory. While a single particle image crosses several light-receiving elements, it moves upward from the light-receiving surface due to sedimentation of the particles.
On the other hand, new particles enter the light-receiving surface from below (because it is projected upside down). Therefore, if the above-described operation is continued for a certain period of time, electrophoretic velocity data for particles on the order of 10 ³ will be accumulated in the memory. As described above, this data is obtained by adding 1 each time the velocity is detected using the velocity numerical value as an address, so it becomes digital data of the profile of the electrophoretic velocity distribution. Alternatively, calculations may be made to immediately calculate the average speed from each speed data obtained as described above.

The electrophoresis measuring device of the present invention has the above-described configuration, and if two or more particle images are simultaneously formed on one light-receiving element, measurement errors will appear. In this method, the grid pitch is preferably about twice the particle diameter of the sample to be measured, so the grid had to be changed depending on the particle size, but in the present invention, the size of one photodetector is limited to about 1 mm in width. It has the advantage that the size of the particles does not have to be a problem because they can be large rather than being small.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing details of the time measuring circuit described above. 1... Electrophoresis tube, 2... Lens, 3... Light receiving surface, 4... Timing circuit, 5... Data processing device, P
1~Pn...Photodetector, C1~Cn _-1 ...Comparator, Cp...Pulse generator, K1~Kn _-2
……counter.

Claims (1)

[Claims] 1 A plurality of light-receiving elements are arranged parallel to the direction of electrophoresis of visible particles, an optical system for forming a floating particle image is arranged on the light-receiving surface of the array of light-receiving elements, and a floating particle image is formed on each light-receiving element. An electrophoresis measurement device that is equipped with a circuit that measures the time during which an output is produced due to the presence of a sensor, and a data processing device that performs appropriate calculations such as calculation of the frequency distribution and average of the output on the output of each of these time measurement circuits.