TWI847911B - Non-invasive blood glucose monitor based on plasma Fano resonance - Google Patents

Abstract

The present invention is a non-invasive blood glucose monitor based on Plasmonic Fano Resonance (PFR). A Plasmonic Fano Resonance sensor is bound to a human skin by a band to monitor the blood glucose changes of a subject in a non-invasive manner. The Plasmonic Fano Resonance sensor and the blood glucose in the human skin have a resonant frequency in the 3.25 GHz and 4.67 GHz ranges. The blood glucose changes are monitored by the changes in the vibration amplitude and frequency values sensed by the Plasmonic Fano Resonance sensor, and the changes in blood glucose can be reflected with high precision.

Description

Non-invasive blood glucose monitor based on plasma Fano resonance

The present invention relates to a blood glucose monitor, and more particularly to a non-invasive blood glucose monitor.

Diabetes is a metabolic disease that requires long-term and regular use of medication and diet control. Regular self-monitoring of blood sugar can serve as a basis for adjusting diabetes medication and diet control. Good blood sugar control can reduce the occurrence of hypoglycemia and ketoacidosis, and prevent the occurrence of complications.

Traditionally, self-monitoring of blood sugar requires the use of a blood collection needle to collect blood, which is painful. Therefore, as Taiwan Announcement No. I749984B discloses a "disposable blood collection safety needle structure and method capable of reducing stinging sensation", the pain can be reduced. However, there is still a risk of infection that may invade the human body and damage the finger skin.

Non-invasive blood glucose monitoring methods can be divided into four categories: optical, electrochemical, electromagnetic (EM) and electromechanical. Optical methods have low signal resolution and are difficult to be widely used. Electrochemical methods require the collection of sweat, saliva, urine and tears to detect blood glucose concentration, but they are affected by the constant changes in the body and vary greatly. For example, the electromechanical method of ultrasound works by allowing ultrasound to penetrate deeply into the skin and tissues. In terms of calculating blood glucose concentration, it displays accurate data, but it will be affected by temperature changes, which affects the accuracy.

As for the electromagnetic (EM) method, in order to introduce current into the human body from one side and receive it on the other side, the relevant impedance is found according to the Ohm standard. Tissues and blood containing fluids and ions (i.e., Na+, K-, and Cl-) play a unique role in conducting current in the human body, that is, blood sugar content is associated with a specific resonant frequency, which is proportional to the impedance of the human body. However, the problem with the electromagnetic method is that it often interferes with the blood sugar-related signals, and it is not possible to track the fluctuations of blood sugar satisfactorily.

Therefore, the main purpose of the present invention is to disclose a non-invasive blood glucose monitor, which uses a plasma Fano resonance sensor that has good impedance matching with the human body and can respond to changes in blood glucose with high precision.

The present invention provides a non-invasive blood glucose monitor based on plasma Fano resonance for monitoring blood glucose changes in the skin of a subject, comprising a plasma Fano resonance sensor, a restraining element and a frequency receiver, wherein the plasma Fano resonance sensor and the blood glucose in the skin of the subject have a resonant frequency in the 3.25 GHz band and the 4.67 GHz band. The restraining element allows the plasma Fano resonance sensor to be fixedly attached to the skin of the subject. The frequency receiver is electrically connected to the plasma Fano resonance sensor and receives a real-time resonant frequency of blood sugar in the human skin monitored by the plasma Fano resonance sensor.

Accordingly, the present invention can monitor the real-time harmonic frequency of blood sugar in the human skin to obtain the vibration amplitude and frequency value changes of the subject under different conditions, and these changes are related to blood sugar and can reflect the changes of blood sugar with high precision.

In order to enable you to have a deeper understanding and recognition of the features, purposes and effects of the present invention, a better embodiment is listed below with accompanying drawings:

Please refer to "Figure 1" and "Figure 2", the present invention provides a non-invasive blood glucose monitor based on plasma Fano resonance for monitoring blood glucose changes in the human skin 11 of a subject 10, comprising a plasma Fano resonance sensor 20, a restraint element 30 and a frequency receiver 40, wherein the plasma Fano resonance sensor 20 and the blood glucose in the human skin 11 have a resonant frequency located in the 3.25 GHz segment and the 4.67 GHz segment. In one embodiment, the plasma Fano resonance sensor 20 is manufactured using a 50 mil glass fiber reinforced PTFE (polytetrafluoroethylene) substrate with a dielectric constant of 10.2, such as a 50 mil Rogers 6010 substrate. The plasma Fano resonance sensor 20 has seven short-circuited stubs 21.

In one embodiment, the structure of the plasma Fano resonant sensor 20 is pre-simulated and optimized in ADS (Advanced Design System @Agilent) to achieve the highest sensitivity. After optimization, the layout of the plasma Fano resonant sensor 20 is printed on a 50 mil Rogers 6010 substrate. After this step, the printed layout is etched with aluminum sulfate for one hour. The etched sensor is inspected under a microscope to check the circuit. The next step is to add SMA coaxial connectors to the circuit so that it can be measured by a vector network analyzer (VNA).

The restraining element 30 allows the plasma Fano resonance sensor 20 to be fixedly attached to the human skin 11 of the subject 10. In one embodiment, the restraining element 30 is a strap 31, which is tied to an arm 12 of a subject 10 and compresses the plasma Fano resonance sensor 20 to be fixedly attached to the human skin 11 of the subject 10.

The frequency receiver 40 is electrically connected to the plasma Fano resonance sensor 20, and receives a real-time harmonic frequency of blood glucose at the human skin 11 monitored by the plasma Fano resonance sensor 20. In one embodiment, the frequency receiver 40 is an oscilloscope 41, and the oscilloscope 41 displays the waveform of the real-time harmonic frequency for reference by the subject 10. In other embodiments, the frequency receiver can be a server, a smart host or a smart watch, etc.

Please refer to "FIG. 3A", "FIG. 3B" and "FIG. 3C", which are the echo loss (S11)-frequency response diagrams of the subject 10 measured in the present invention. The subjects were divided into four groups for measurement, one of which was a control group (No MUT: a), which performed empty measurement (the plasma Fano resonance sensor 20 was not attached to the human skin 11). The three groups are Experimental Groups 1 to 3, the plasma Fano resonance sensors 20 are all attached to the human skin 11, and Experimental Group 1 is when the subject 10 is inactive (Arm MUT: b), Experimental Group 2 is when the arm 12 is active for 1 minute (Arm MUT: c), and Experimental Group 3 is when the subject 10 starts to eat honey for 3 minutes (Arm MUT: d), wherein "FIG. 3B" and "FIG. 3C" are partial enlarged views of "FIG. 3A".

From the echo loss-frequency diagrams of the control group and experimental groups 1 to 3, it can be seen that the plasma Fano resonance sensor 20 used in the present invention has a resonant frequency with the blood sugar in the human skin 11 located in the 3.25 GHz segment (the first resonant frequency segment) and the 4.67 GHz segment (the second resonant frequency segment).

Please refer to "Figure 4" again. In the first harmonic frequency range, the vibration amplitude of the instantaneous harmonic frequency of Experimental Groups 1 to 3 has an echo loss of -16.4dB, -17.6dB, and -19.4dB respectively.

Please refer to "Figure 5" again. In the first resonant frequency range, the instantaneous resonant frequency values of Experimental Groups 1 to 3 are 3.278 GHz, 3.277 GHz, and 3.255 GHz, respectively.

Experimental groups 1 to 3 correspond to the states of the subject 10 not moving, the arm 12 moving for 1 minute, and the subject 10 eating honey for 3 minutes, respectively. Therefore, the trend of the vibration amplitude and frequency value change of the real-time harmonic frequency is consistent with the theoretical change trend of blood sugar (the arm 12 moving and the subject 10 eating honey will increase blood sugar).

Please refer to "Figure 3C" again. In the second resonant frequency range, the vibration amplitude of the instantaneous resonant frequency of Experimental Groups 1 to 3 has an echo loss of -26dB (Arm MUT: b), -25dB (Arm MUT: c), and -21.8dB (Arm MUT: d), respectively.

Please refer to "Figure 6" again. In the second resonant frequency range, the values of the instantaneous resonant frequencies of Experimental Groups 1 to 3 are 4.6794 GHz, 4.6798 GHz, and 4.6798 GHz, respectively.

Similarly, Experimental Groups 1 to 3 correspond to the states of the subject 10 being inactive, the arm 12 moving for 1 minute, and the subject 10 starting to eat honey for 3 minutes. Obviously, in the second harmonic frequency range, the vibration amplitude of the instant harmonic frequency of Experimental Group 3 (eating) has a significant change.

The changes in the vibration amplitude and frequency value of the real-time harmonic frequency can reflect the changes in blood sugar with high precision. Therefore, by observing the changes in the vibration amplitude of the real-time harmonic frequency, the changes in blood sugar can be inferred.

In summary, the advantages of the present invention include at least:

1. The plasma Fano resonance sensor is attached to the human skin using the strap to monitor the blood sugar changes of the subject in a non-invasive manner, thereby relieving the problems of pain and wound infection.

2. By monitoring the changes in vibration amplitude and frequency values in two frequency ranges, it can reflect changes in blood sugar with high precision.

10: Subject 11: Human skin 12: Arm 20: Plasma Fano resonance sensor 21: Stub 30: Restraint element 31: Strap 40: Frequency receiver 41: Oscilloscope

Figure 1 is a schematic diagram of the structure of the plasma Fano resonance sensor of the present invention. Figure 2 is a schematic diagram of the monitoring structure of the present invention. Figures 3A-3C are echo loss-frequency response diagrams measured by the subjects of the present invention. Figure 4 is an echo loss diagram of the present invention in the first resonant frequency segment. Figure 5 is a real-time resonant frequency diagram of the present invention in the first resonant frequency segment. Figure 6 is a real-time resonant frequency diagram of the present invention in the second resonant frequency segment

10: Subjects

11: Human skin

12: Arms

20: Plasma Fano resonance sensor

30: Restraint element

31: drawstring

40: Frequency receiver

41: Oscilloscope

Claims (5)

A non-invasive blood glucose monitor based on plasma Fano resonance for monitoring blood glucose changes in the skin of a subject, comprising: a plasma Fano resonance sensor, the plasma Fano resonance sensor and the blood glucose in the skin of the subject have a resonant frequency in the 3.25 GHz band and the 4.67 GHz band; a restraining element, the restraining element allows the plasma Fano resonance sensor to be fixedly attached to the skin of the subject; and A frequency receiver, which is electrically connected to the plasma Fano resonance sensor and receives a real-time resonant frequency of blood sugar in the human skin monitored by the plasma Fano resonance sensor. A non-invasive blood glucose monitor as described in claim 1, wherein the plasma Fano resonance sensor is manufactured using a 50 mil glass fiber reinforced PTFE (polytetrafluoroethylene) substrate with a dielectric constant of 10.2. A non-invasive blood glucose monitor as described in claim 2, wherein the plasma Fano resonance sensor has 7 short-circuited stubs. A non-invasive blood glucose monitor as described in claim 1, wherein the restraint element is a belt, which is tied to an arm of the subject and compresses the plasma Fano resonance sensor to be fixedly attached to the skin of the subject. A non-invasive blood glucose monitor as described in claim 1, wherein the frequency receiver is an oscilloscope, and the oscilloscope displays the waveform of the real-time resonant frequency.