JPH04244944A - Quartz vibrator potassium biosensor - Google Patents

Abstract

PURPOSE:To easily and inexpensively measure the amount of a potassium ion by forming a lipid film of valinomycin on the surface of a quartz vibrator to measure a frequency change. CONSTITUTION:A quartz vibrator potassium biosensor 25 using a quartz vibrator 24 having a valinomycin lipid film formed on the surface thereof is immersed in an aqueous potassium solution and frequency is measured by a frequency counter 26. In this case, since said frequency changes corresponding to the wt. change of the substance bonded to the surface of the vibrator as shown by formula F=KX m (F: frequency change quantity, K: constant, m: adhesion wt. change), the amount of potassium can be measured by calculating the change of frequency. Since the quartz vibrator potassium biosensor 25 is constituted by forming only the valinomycin lipid film on the surface of the quartz vibrator 24, this biosensor is inexpensive and the measuring operation thereof is also simple.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to a quartz crystal potassium biosensor. More specifically, the present invention relates to a potassium biosensor that uses a crystal oscillator to simplify the detection and quantification of potassium ions.

0002

[Prior Art] In conventional technology, when attempting to measure potassium ion concentration in an aqueous solution, etc., large devices use atomic absorption spectroscopy, while small devices use ion electrodes, etc. . However, all of these devices have the drawback of being expensive.

0003

SUMMARY OF THE INVENTION An object of the present invention is to provide a quartz crystal oscillator potassium biosensor that simplifies the detection and quantification of potassium ions and is accordingly inexpensive.

0004

[Means for Solving the Problems] The purpose of the present invention is to
This is achieved using a quartz crystal potassium biosensor with a valinomycin lipid film formed on the surface of the quartz crystal.

[0005] Valinomycin is used in the actinomycete Strepto
myces fulvissimus (1955) and S
．． [(D
-valine)-(L-lactic acid)-(L-valine)-(D-α
-Hydroxyisovaleric acid)-]3. It is effective against Gram-positive bacteria and is also effective in treating mice infected with sleeping pathogens.

[0006] It also enhances potassium ion transport in mitochondria and red blood cell membranes, and this is understood to be because a hydrophobic ring encloses potassium ions in the center and allows them to pass through the membrane. This is thought to be due to the strong binding of potassium ions to the carbonyl groups in their structure, and this binding effect inhibits the ion permeability of biological membranes, causing E. coli,
It shows antibacterial properties against plants such as Candida albicans.

In the present invention, it is possible to quantify potassium ions by forming a lipid film of valinomycin having such an effect on the surface of a crystal resonator.

As a crystal oscillator, a crystal oscillator with an AT cut and a vibration frequency of 5 MHz or more is preferably used, and an example of its use is shown in a plan view in FIG. A silver electrode 22 is attached to the center of the crystal surface 21, and lead wires 23, 23 are drawn out from each of the silver electrodes also attached to the back side.

The formation of a valinomycin lipid film on the surface of the crystal resonator is carried out by a lipid film formed by a polyion complex such as N,N-dimethyl-N,N-dihigher alkyl polystyrene sulfonic acid represented by the general formula.

That is, valinomycin does not have a functional group effective for immobilization, and therefore is not suitable for covalent immobilization. Further, even when entrapping immobilization with a membrane, since the molecule of valinomycin itself is small (molecular weight 741), it leaks through the pores of the membrane. However, since it has the characteristic that it can be stably immobilized in a lipid membrane, a lipid membrane made of a polyion complex such as the above-mentioned N,N,N,N-tetraalkyl polystyrene sulfonic acid is used for immobilization.

[0011] Valinomycin lipid membrane has a concentration of about 0.5 to
The quartz crystal is placed at room temperature for about 10 seconds in a chloroform solution containing 10% by weight, typically 1% by weight of valinomycin and a polyion complex at a concentration of about 0.5-20% by weight, typically 5% by weight. It is formed by soaking it for about 10 minutes, generally about 1 minute, taking it out, and air drying it.

0012

[Operation] As shown in the formula below, the frequency of the crystal oscillator changes in response to changes in the weight of substances attached to the surface, so the amount of potassium can be measured with high sensitivity based on this principle. be able to. ΔF=K・Δm ΔF: Frequency change Δm: Adhesive weight change K: Constant

[0013]

[Effects of the Invention] The crystal oscillator potassium biosensor according to the present invention is inexpensive because it only has a valinomycin lipid film formed on the surface of the quartz crystal oscillator, and the measurement operation using it is also simple. It is.

[0014]

[Example] Next, the present invention will be explained with reference to an example.

Example 0.1 g of valinomycin and the N,N-dimethyl-
N,N-distearylpolystyrene sulfonic acid 0.5g
A crystal resonator of the shape shown in Fig. 1 (manufactured by Yakumo Tsushin Kogyo, AT
The cut sample (vibration frequency: 6 MHz) was immersed for 1 minute at room temperature, then pulled out and dried.

An example of a frequency measuring circuit using one crystal oscillator 25 having a valinomycin lipid film formed on its surface in this manner is shown in FIG. The amount of potassium ions in an aqueous solution was measured using a frequency measuring device designed to measure the amount of potassium ions in an aqueous solution.

That is, the final concentration of potassium ions is 0.02, 0.04, 0.06, 0.08 or 0.02, respectively.
This was done by immersing the above-mentioned quartz crystal potassium biosensor in an aqueous solution adjusted to have a concentration of 10% by weight for 90 seconds, and measuring the difference in frequency change (ΔF). As a result, a good linear relationship as shown in the graph of FIG. 3 was obtained with a sensitivity of about -1 Hz/0.01% by weight potassium ion concentration. Note that it took about 60 seconds until the response became constant.

[Brief explanation of the drawing]

FIG. 1 is a plan view of one embodiment of a crystal resonator used in the present invention.

FIG. 2 is an example of a frequency measurement circuit of a quartz crystal potassium biosensor according to the present invention.

FIG. 3 is a graph showing the relationship between potassium ion concentration and frequency change in Examples.

[Explanation of symbols]

21 Crystal surface 22 Silver electrode 24 Crystal resonator 25 Crystal resonator potassium biosensor 26 Frequency counter

Claims (2)

[Claims] 1. A potassium quartz crystal oscillator biosensor comprising a valinomycin lipid film formed on the surface of the quartz crystal oscillator. 2. The quartz crystal potassium biosensor according to claim 1, wherein the lipid membrane is formed by a polyion complex.