JPH08189891A - Non-invasive biochemical measuring device - Google Patents

Abstract

(57) [Summary] [Object] To provide a device capable of non-invasively performing quantitative analysis of glucose in blood. [Structure] Including a light source, photodetector, signal processing / calculation unit, 2
Has radiation sensitivity in the wavelength range of 000nm to 2220nm,
A light source having a maximum value of radiation sensitivity in a wavelength range of 2065 nm to 2085 nm, or 1450 nm to 1650 n
A light source having a radiation sensitivity in the range of m and having a maximum value of the radiation sensitivity at 1550 nm was used. [Effect] The characteristic light absorption of glucose can be utilized. Moreover, since the light of the above wavelength can be transmitted through the living body to some extent, noninvasive glucose analysis can be performed by measuring the transmitted light intensity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biochemical analysis device for medical use, and more particularly to a device for rapidly measuring biochemical components in a living body without collecting blood.

[0002]

2. Description of the Related Art An apparatus for non-invasively measuring oxygen saturation in a living body using near infrared light is a pathophysiology, vol. 10, 1991.
Year pp. 558-588. This paper discusses a system that uses semiconductor lasers having wavelengths of 780 nm, 805 nm, and 830 nm, sequentially irradiates a living tissue with laser light by a time division method, detects reflected or transmitted light, and calculates oxygen saturation. .

[0003]

However, the prior art is 7
Since light with a wavelength of 80 nm to 830 nm is used,
It can be used only for the measurement of oxygenated hemoglobin or reduced hemoglobin, and the more important biochemical component cannot be measured by clinical examination.

It is an object of the present invention to provide an apparatus capable of non-invasively quantitatively analyzing biological substances other than hemoglobin, particularly glucose in blood.

[0005]

Among the biochemical items, glucose has infrared absorption peaks at 2075 nm and 1550 nm. The present invention irradiates a living body with light of the above wavelength and detects the intensity of transmitted light with a photodetector having sensitivity in the above wavelength range, thereby quantifying blood glucose concentration without collecting blood. It is what

[0006]

In the past, light having a wavelength of 1300 nm or more was absorbed by water in the living body, so that it was difficult to measure transmitted light and it was not used for non-invasive measurement. However, water absorption is not large over all wavelengths, and there is a wavelength region in which water absorption is small. Therefore, if there is a biochemical component having absorption in a wavelength range where water absorption is small, the biochemical component can be measured. Further, the signal / noise ratio can be increased by optimizing the thickness of the living body to be measured and the irradiation light intensity, and thus the above-mentioned problem can be solved.

Since the light source and the photodetector are made of a semiconductor material and can be manufactured in a small size and at a relatively low cost, a small and inexpensive non-invasive glucose analyzer can be provided.

[0008]

EXAMPLE FIG. 1 shows an infrared absorption spectrum of a glucose aqueous solution. Wave number 4818 indicated by the arrow in the figure
(1 / cm), that is, the absorption peak at a wavelength of 2075 nm is based on glucose. Therefore, wavelength 2
075 nm has a special significance in measuring glucose. On the other hand, the absorption of glucose having a wave number of 6452 (1 / cm), that is, a wavelength of 1550 nm overlaps with the absorption of water and does not clearly appear as an absorption peak.
When the relationship between the absorption intensity of light at 550 nm and the glucose concentration is examined, a correlation is obtained as shown in FIG. Therefore, it is understood that the light having the wavelength of 1550 nm is also effective for the quantitative analysis of glucose. From the above, the wavelength is 2075 nm
A light source of 1550 nm and a photodetector sensitive to the above wavelengths are indispensable for the quantitative analysis of glucose, and have characteristics that cannot be obtained at other wavelengths.

FIG. 3 shows the configuration of a non-invasive glucose analysis using a light source and a photodetector. The semiconductor laser 1 and the semiconductor photodetector 2 are placed facing each other, and the biological sample 3 is placed therebetween. The semiconductor laser drive circuit 4 emits light from the semiconductor laser to irradiate the biological sample, the transmitted light is measured by the photodetector, and the computer 6 through the signal processing circuit 5 performs arithmetic processing such as concentration conversion. is there. By using the wavelength, glucose in a living body can be non-invasively quantitatively analyzed with such a simple configuration.

FIG. 4 shows a first embodiment of the present invention. A hole 8 for inserting a living body such as a finger is provided in the analyzer main body 7. The cross-sectional structure of the periphery of the hole is shown in (b). The semiconductor laser 1 and the photodetector 2 are installed facing each other on the inner surface of the hole, and the light absorption of the living body inserted in the hole can be measured. it can. A display unit 9 is installed on the front panel of the analyzer body, and the measured glucose concentration is displayed.

FIG. 5 shows a second embodiment of the present invention. The semiconductor laser 1 and the photodetector 2 are respectively installed on the support structure 10, the support structure is arranged so that the semiconductor laser and the photodetector face each other, and the semiconductor laser 1 and the photodetector 2 are coupled by the coupling portion 11. The coupling is provided with a spring so that the semiconductor laser and the photodetector are always pressed against each other with a constant pressure. The biological sample is installed between the semiconductor laser and the photodetector by opening a support structure provided with the semiconductor laser and the photodetector. The semiconductor laser and the photodetector are connected to the device main body 1 by flexible wiring 12.
Connected to 3. In this embodiment, by sandwiching a biological sample with a semiconductor laser and a photodetector, the sample can be always attached to a biological body such as an earlobe and is suitable for continuous glucose monitoring.

FIG. 6 shows the effect of this embodiment. This is the first
4 shows the time-dependent change in glucose concentration when a glucose tolerance test was carried out using the above-mentioned Example. 207 for the light source
A 5 nm semiconductor laser was used. The solid line in the figure is the result of continuous measurement of changes in glucose concentration measured according to the present invention, and the measurement points are the results of point-by-point measurement by the conventional method. From this, the present invention and the conventional method are in good agreement, and since the continuous measurement of the present invention is possible, the effectiveness of the present invention was shown.

[0013]

According to the present invention, 2075 nm or 1
Since the light of 550 nm is used, the characteristic light absorption of glucose can be utilized. Moreover, since the light of the above wavelength can be transmitted through the living body to some extent, noninvasive glucose analysis can be performed by measuring the transmitted light intensity.

[Brief description of drawings]

FIG. 1 is a characteristic diagram of an infrared absorption spectrum of a glucose aqueous solution.

FIG. 2 is a characteristic diagram showing the relationship between glucose concentration and transmitted light intensity.

FIG. 3 is a block diagram showing a configuration of the present invention.

FIG. 4 is an explanatory diagram of the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a second embodiment of the present invention.

FIG. 6 is an explanatory view showing the effect of the present invention.

[Explanation of symbols]

1 ... Light source, 2 ... Photodetector, 7 ... Analytical apparatus body, 8 ... Hole,
9 ... Display section.

Claims (3)

[Claims] 1. A biochemical measurement device including a light source, a photodetector, a signal processing / calculation unit, which directly irradiates light on a living body to obtain the concentration of a biochemical substance in the living body by absorbing the light, and at least 2000 nm Source having a radiant energy in the wavelength range from 20 to 2220 nm and a radiant energy maximum in the wavelength range from 2065 nm to 2085 nm, or having a radiant energy in the range from at least 1450 nm to 1650 nm and a radiant energy maximum at 1550 nm. A non-invasive biochemical measuring device characterized by using an existing light source. 2. The light source according to claim 1, wherein the light source is gallium,
A semiconductor laser made of a material in which a plurality of indium, arsenic, antimony, phosphorus, and aluminum are combined and mixed with an appropriate composition, and a photodetector is made of germanium, indium arsenide, indium antimony, lead sulfide, or lead selenide. A non-invasive biochemical measuring device that is a semiconductor photodetector. 3. The light emitting surface of the light source according to claim 1 and the light receiving surface of the photodetector are arranged at a predetermined interval, and the biological sample is placed between the light emitting surface and the light receiving surface. Invasive biochemical measuring device.