Non-destructive biological profiling device including spatial resolution and method of operation thereof

Abstract

An impedance measuring device according to an embodiment of the present invention includes three or more electrodes electrically connected to biological tissue, a power supply unit including first and second terminals and supplying power via the first and second terminals, a multiplexing circuit selecting at least some of the electrodes and connecting them to the first and second terminals, and a controller providing an electrode selection signal to the multiplexing circuit including information about the electrodes connected to the first and second terminals, and can measure the impedance of the biological tissue by measuring the electrical signal between the first and second terminals.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to non-destructive biological profiling devices including spatial resolution, and more particularly to impedance measurement devices and methods of operation for measuring impedance of biological tissue. [Background technology]

[0002] In recent years, as time and cost inefficiencies in new drug development have rapidly increased, there is a growing need for biological models that can more accurately predict drug efficacy and toxicity. Currently, two-dimensional (2D) cell line models are mainly used in early drug screening, but there are various difficulties in emulating phenomena that occur in the body using 2D cell cultures, and most new drug candidates that have shown low toxicity and high efficacy in preclinical studies have not passed clinical trials.

[0003] Microphysiological systems (MPS) such as organoids and organ-on-a-chip replicate the bodily organs, functions, or phenomena to be tested by culturing appropriate cell lines or primary cells on a 3D structure to create a 3D cell culture model. Recently, with the development of multi-organ-on-chips, in which identical organ-on-chips are arranged in parallel, and human-on-chips, which are made up of different organ-on-chips, innovations are accelerating to create an environment that is even closer to the human body, allowing for the rapid development of new drugs that are safer, more effective, have fewer side effects, and are less expensive.

[0004] Just as uniformity is difficult to achieve in living organisms, the uniformity of individual microphysiological systems must be confirmed nondestructively to enable effective drug screening using microphysiological systems. Electrical measurement is an effective method for achieving this. Among these, transepithelial electrical resistance (TEER) measurement is an important tool for evaluating the barrier function of cell layers in cell culture models and is a representative nondestructive testing method. TEER (transepithelial electrical resistance) is a method for measuring the resistance or low-frequency impedance of biological tissues and is widely used as a nondestructive analytical method for quantitatively measuring tight junctions in biological tissues. Stronger intercellular junctions suppress electrolyte migration, resulting in higher resistance values. However, as intercellular junctions weaken due to physicochemical stimuli or aging, resistance values ​​decrease. This can be used to evaluate drug toxicity and efficacy.

[0005] However, conventional TEER measurement methods can only measure the entire surface of a single object, making it difficult to accurately identify local differences on the surface of the object or the location of damage in the cell layer. Furthermore, conventional devices have issues with error-inducing factors in the measurement environment, the inconvenience of complex protocols required to prepare the measurement environment, and low repeatability and reproducibility.

[0006] Therefore, a new TEER measurement device that can solve the conventional problems is needed. Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE INVENTION Embodiments of the present invention provide an impedance measurement device and method for analyzing electrical properties depending on the location within biological tissue. [Means for solving the problem]

[0008] An impedance measuring device according to an embodiment of the present invention includes three or more electrodes electrically connected to biological tissue, a power supply unit including first and second terminals and supplying power via the first and second terminals, a multiplexing circuit selecting at least some of the electrodes and connecting them to the first and second terminals, and a controller providing an electrode selection signal to the multiplexing circuit including information about the electrodes connected to the first and second terminals, and can measure the impedance of the biological tissue by measuring the electrical signal between the first and second terminals.

[0009] An operating method of an impedance measuring device according to an embodiment of the present invention includes the steps of electrically connecting three or more electrodes to biological tissue (step 1), a multiplexing circuit selecting at least some of the electrodes and connecting them to first and second terminals (step 2), measuring the impedance of the biological tissue via the first and second terminals (step 3), changing the electrode connected to at least one of the first and second terminals (step 4), and measuring the impedance of the biological tissue via the first and second terminals (step 5). [Effects of the Invention]

[0010] According to the present technology, an impedance measuring device and an operating method thereof are provided that can analyze electrical characteristics according to positions in biological tissue, thereby enabling precise analysis of spatial characteristics within biological tissue. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram illustrating an impedance measuring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining the multiplexing circuit of FIG. 1 in more detail. [Figure 3] 3A and 3B are diagrams illustrating a sample holder and an upper cover of an impedance measuring device according to an embodiment of the present invention. [Figure 4] 4 is a flowchart illustrating an operation method of an impedance measuring apparatus according to an embodiment of the present invention. [Figure 5] 1A and 1B are diagrams illustrating images generated by an impedance measuring device according to an embodiment of the present invention. [Figure 6] 1 is a diagram comparing a biological tissue to be measured with an image generated by an impedance measuring device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Best Mode for Carrying Out the Invention> Structural or functional descriptions of the embodiments disclosed in this specification or application are merely provided for the purpose of describing embodiments according to the technical concept of the present invention, and embodiments according to the technical concept of the present invention may be implemented in various forms other than the embodiments disclosed in this specification or application, and the technical concept of the present invention should not be construed as being limited to the embodiments described in this specification or application.

[0013] FIG. 1 is a block diagram illustrating an impedance measuring device according to an embodiment of the present invention.

[0014] Referring to FIG. 1, an impedance measuring device 1000 includes an electrode section 100 , a multiplexing circuit 200 , a controller 300 and a power supply section 400 .

[0015] The electrode unit 100 may include three or more electrodes. The electrodes may be electrically connected to the biological tissue to be measured. As used herein, "electrically connected" may mean being in direct contact with the biological tissue to be measured or being connected to each other via a medium having electrical conductivity. In one embodiment, the electrodes may be in direct contact with the biological tissue to be measured. In another embodiment, the electrodes may be electrically connected to the biological tissue to be measured via an electrolyte. As used herein, "electrically connected" between the electrodes and the biological tissue means that it is sufficient for current to flow when power is applied later, and it is not necessary that power be applied at the moment of connection.

[0016] In some embodiments, the biological tissue may be a tissue isolated from a living organism or a cultured cell. For example, the cell culture may be a spheroid or an organoid. In some embodiments, the electrode may be a switchable electrode.

[0017] The multiplexing circuit 200 can select at least some of the electrodes and connect them to the power supply unit 400, more specifically, to terminals of the power supply unit 400. The multiplexing circuit 200 can receive an electrode selection signal from the controller 300 and can select an electrode to be connected to each terminal based on the received electrode selection signal.

[0018] The controller 300 can control the multiplexing circuit 200. In an embodiment, the controller 300 can provide an electrode selection signal to the multiplexing circuit 200, and the electrode selection signal can include information about an electrode coupled to each terminal of the power supply unit 400. In an embodiment, the controller 300 can control the multiplexing circuit 200 to change the electrode coupled to each terminal. For example, the controller 300 can provide a new electrode selection signal to the multiplexing circuit 200, the new electrode selection signal including information about an electrode to be newly coupled to the terminal, and the multiplexing circuit 200 can accordingly select and couple a new electrode to each terminal.

[0019] In one embodiment, the controller 300 can change the electrodes connected to each terminal according to a predetermined order. That is, the impedance measuring device 1000 can include a memory (not shown) that can store information about the order of electrode combinations connected to each terminal. The controller 300 can provide an electrode selection signal to the multiplexing circuit 200 based on the information about the order of electrode combinations stored in the memory (not shown).

[0020] The power supply unit 400 may include a first terminal and a second terminal. In an embodiment, one or more electrodes may be electrically connected to each of the first terminal and the second terminal. In an embodiment, the electrodes connected to the first terminal and the second terminal may be different from each other. The power supply unit 400 may supply power via the first terminal and the second terminal, and the power supplied from the power supply unit 400 may be supplied to the biological tissue to be measured via the electrodes connected to the first terminal and the second terminal. The power may be, for example, a current or a voltage, and the current or the voltage may be a direct current or an alternating current, respectively. In an embodiment, the first terminal may include a first current terminal and a first voltage terminal, and the second terminal may include a second current terminal and a second voltage terminal. In an embodiment, the same electrodes may be connected to the first current terminal and the first voltage terminal, but the present invention is not limited thereto. In another embodiment, different electrodes may be connected to the first current terminal and the first voltage terminal. In one embodiment, the same electrode may be connected to the second current terminal and the second voltage terminal, but is not limited thereto, and in another embodiment, different electrodes may be connected to the second current terminal and the second voltage terminal, and in another embodiment, the electrodes not connected to the first terminal and the second terminal may be electrically insulated.

[0021] The impedance measuring device 1000 can measure the impedance of biological tissue by measuring an electrical signal between the first terminal and the second terminal. In one embodiment, the power supply unit 400 can apply a current through the first current terminal and the second current terminal, and the impedance of the biological tissue can be measured by measuring a voltage between the first voltage terminal and the second voltage terminal in response to the applied current. In one embodiment, the applied current can be 10 mA or less, more specifically, 0.5 μA to 20 μA, but is not limited thereto. A current of different magnitudes can be applied depending on the size and condition of the object to be measured. In another embodiment, the power supply unit 400 can apply a voltage through the first voltage terminal and the second voltage terminal, and the impedance of the biological tissue can be measured by measuring a current flowing through the first current terminal and the second current terminal in response to the applied voltage. In one embodiment, the applied voltage can be 30 V or less, more specifically, 50 mV to 10 V, but is not limited thereto. A voltage of different magnitudes can be applied depending on the size and condition of the object to be measured.

[0022] In an embodiment, the impedance measuring device 1000 may further include a calculation unit 500. The calculation unit 500 may calculate electrical characteristics according to positions in the biological tissue based on the measured impedance and the positions of the electrodes. In an embodiment, the electrical characteristics according to positions may be expressed as an impedance value, an electrical conductivity value, etc., but are not limited to specific examples.

[0023] For example, in one measurement sequence in which a certain combination of electrodes is connected to the first and second terminals, the positions of the electrodes connected to the first and second terminals and the impedance values ​​measured in the corresponding measurement sequence can be stored in the impedance measuring device 1000. By repeating multiple measurement sequences while changing the electrode combination, multiple impedance values ​​and corresponding electrode positions can be stored in the impedance measuring device 1000, and the calculation unit 500 can calculate electrical characteristics according to positions in the biological tissue based on the multiple impedance values ​​and corresponding electrode positions stored in the impedance measuring device 1000. In an embodiment, the calculation unit 500 can calculate the electrical characteristics by further using a correction coefficient to take into account the asymmetric and non-uniform shape of the biological tissue.

[0024] In an embodiment, the impedance measuring device 1000 may further include an image generating unit 600. The image generating unit 600 may generate an image showing electrical characteristics of biological tissue based on the electrical characteristics according to the position calculated by the calculating unit 500.

[0025] Therefore, the impedance measuring device 1000 according to the embodiment of the present invention can provide multidimensional electrical property measurement data for biological tissue. That is, the impedance measuring device 1000 according to the embodiment of the present invention can measure non-uniform or localized changes in biological tissue by providing spatial resolution.

[0026] FIG. 2 is a diagram for explaining the multiplexing circuit of FIG. 1 in more detail.

[0027] 2, electrodes 100a, 100b, and 100c may be connected to a multiplexing circuit 200. Although three electrodes 100a, 100b, and 100c are illustrated in FIG. 2, the number of electrodes connected to the multiplexing circuit 200 is not limited thereto, and may be four or more.

[0028] The multiplexing circuit 200 can receive an electrode selection signal from the controller 300, and can select electrodes to be connected to the first terminal 410 and the second terminal 420 based on the electrode selection signal, and can connect the selected electrodes to the first terminal 410 and the second terminal 420.

[0029] Controller 300 can provide new electrode selection signals to multiplexing circuit 200 , causing multiplexing circuit 200 to change the electrodes coupled to first terminal 410 and second terminal 420 .

[0030] FIG. 3 is a diagram illustrating a sample holder and an upper cover of an impedance measuring device according to an embodiment of the present invention.

[0031] 3, the impedance measuring device 1000 may include a sample holder 700. A biological tissue may be placed in the sample holder 700. In one embodiment, a biological tissue cultured in a transwell may be placed in the sample holder.

[0032] The impedance measuring device 1000 may also include a top cover 800. The top cover 800 may be disposed on the sample holder 700. In one embodiment, the sample holder 700 and the top cover 800 may be hinged to form a clam-shell structure, but are not limited to such a structure.

[0033] 3, three or more electrodes of the impedance measuring device 1000 may be fixed to the upper cover 800. In another embodiment, some of the three or more electrodes of the impedance measuring device 1000 may be fixed to the upper cover 800, and other parts may be fixed to the sample holder 700. By placing the upper cover 800 on the sample holder 700, the electrodes may be electrically connected to the biological tissue 2000. In an embodiment, by fixing the electrodes to the upper cover 800 or the sample holder 700, the impedance measuring device 1000 may measure impedance without deviation due to movement of the electrodes, thereby enabling more accurate measurement of the electrical properties of the biological tissue.

[0034] In one embodiment, the impedance measuring device 1000 may minimize noise generation by electrically shielding the internal space between the sample holder 700, in which the biological tissue is placed, and the upper cover 800, or by providing an additional vibration-absorbing pad, etc. In another embodiment, the impedance measuring device 1000 may further include a guarding circuit for removing noise.

[0035] FIG. 4 is a flowchart illustrating a method of operating the impedance measuring device according to an embodiment of the present invention.

[0036] 4, in operation S100, the electrodes may be electrically connected to the biological tissue. For example, as shown in FIG. 3, after placing the biological tissue 2000 on the sample holder 700, the upper cover 800 may be placed on the sample holder 700, thereby electrically connecting the electrodes of the electrode unit 100 fixed to the upper cover 800 or the sample holder 700 to the biological tissue 2000. That is, the electrodes fixed to the upper cover 800 or the sample holder 700 may be in direct contact with the biological tissue 2000 or may be electrically connected to the biological tissue 2000 via an electrolyte.

[0037] In operation S200, the multiplexing circuit can select some of the electrodes to connect to the first and second terminals. As shown in Fig. 2, the multiplexing circuit 200 can receive an electrode selection signal from the controller 300 and can select the electrodes to connect to the first and second terminals based on the electrode selection signal.

[0038] In operation S300, the impedance of the biological tissue can be measured. The impedance of the biological tissue can be measured via the first terminal and the second terminal, and more specifically, can be measured by measuring an electrical signal between the first terminal and the second terminal.

[0039] In operation S400, the electrodes coupled to at least one of the first terminal and the second terminal may be changed. For example, as shown in FIG. 2, the controller 300 may provide a new electrode selection signal to the multiplexing circuit 200, which may cause the multiplexing circuit 200 to change the electrodes coupled to the first terminal and / or the second terminal. In one embodiment, at least a portion of the one or more electrodes coupled to the first terminal and the second terminal may be changed, but this is not intended to be limiting. In another embodiment, only at least a portion of the electrodes coupled to the first terminal may be changed, and in yet another embodiment, only at least a portion of the electrodes coupled to the second terminal may be changed.

[0040] In operation S500, the impedance of the biological tissue can be measured again based on the changed electrodes connected to the first terminal and the second terminal. In an embodiment, operations S400 to S500 can be repeatedly executed. For example, information about the electrode combinations that are changed according to a predetermined order can be stored in the impedance measuring device, and the controller 300 can repeatedly provide a new electrode selection signal to the multiplexing circuit 200 based on the information about the electrode combinations that are changed according to the predetermined order.

[0041] In operation S600, electrical characteristics according to positions in the biological tissue can be calculated. In one embodiment, the impedance measuring device can store position information of the electrodes connected to the first terminal and the second terminal and the corresponding impedance measurement values ​​for each sequence, and can calculate electrical characteristics according to positions in the biological tissue based on the electrode position information and the impedance measurement values.

[0042] The S700 operation can generate an image showing electrical properties of biological tissue. The image showing electrical properties of biological tissue can be generated based on the electrical properties calculated in the S600 operation according to the position within the biological tissue.

[0043] FIG. 5 is a diagram illustrating an image generated by an impedance measuring device according to an embodiment of the present invention.

[0044] Referring to Figure 5, an image generated by the operation S700 of Figure 4 can be seen. Impedance and electrical conductivity values ​​are calculated for each position within the biological tissue, and the electrical conductivity values ​​are displayed in different colors. In other words, the impedance measuring device according to an embodiment of the present invention can provide spatial resolution, thereby enabling measurement of uneven or localized changes within the biological tissue.

[0045] 5, the minimum and maximum impedance values ​​for each location in the biological tissue can be calculated, and the standard deviation of the impedance values ​​for each location in the biological tissue can also be calculated. In one embodiment, information such as the minimum impedance value for each location and its corresponding location, the maximum impedance value for each location and its corresponding location, the average impedance value and standard deviation in the biological tissue, etc. can be provided to the user via a display.

[0046] FIG. 6 is a diagram comparing a biological tissue to be measured with an image generated by an impedance measuring device according to an embodiment of the present invention.

[0047] Referring to FIG. 6, the image on the left is an image of the fluorescent staining (F-actin) result of an intestinal model in which an intestinal epithelial cell line (Caco-2) was cultured, and the image on the right is an image generated by an impedance measuring device according to an embodiment of the present invention.

[0048] Looking at the results of fluorescent staining of the intestinal model, it can be seen that areas with low cell density are displayed in relatively dark colors. Looking at the image of the intestinal model taken with the impedance measurement device, areas measured with low impedance values ​​are displayed in light colors, and areas measured with high impedance values ​​are displayed in dark colors. Since the lower the cell density, the lower the measured impedance value, as can be seen in Figure 6, the image of the intestinal model taken with the impedance measurement device successfully replicates the cell density within the actual intestinal model.

[0049] That is, the impedance measuring device according to the embodiment of the present invention can measure low cell density and epithelial tissue damage at a specific location. [Explanation of symbols]

[0050] 100 Electrode section 200 multiplex circuit 300 Controller 400 Power supply section 500 Calculation Department 600 Image Generation Unit 700 Sample Holder 800 Top Cover 1000 Impedance Measuring Device 2000 Biological Tissue

Claims

1. three or more electrodes electrically coupled to the biological tissue; a power supply unit including a first terminal and a second terminal and supplying power via the first terminal and the second terminal; a multiplexing circuit for selectively connecting at least some of the electrodes to the first terminal and the second terminal; a controller that provides the multiplexing circuit with an electrode selection signal including information regarding electrodes connected to the first terminal and the second terminal; An impedance measuring device that measures the impedance of the biological tissue by measuring an electrical signal between the first terminal and the second terminal.

2. The controller 2. The impedance measuring device according to claim 1, wherein the multiplexing circuit is controlled to change the electrodes connected to the first terminal and the second terminal in accordance with a predetermined sequence.

3. the first terminals include a first voltage terminal and a first current terminal; 2. The impedance measuring device of claim 1, wherein the second terminal includes a second voltage terminal and a second current terminal.

4. The power supply unit applying a current through the first current terminal and the second current terminal; The impedance is 4. The impedance measuring device of claim 3, wherein the impedance is measured by measuring the voltage between the first and second voltage terminals.

5. The power supply unit applying a voltage to the first voltage terminal and the second voltage terminal; The impedance is 4. The impedance measuring device according to claim 3, wherein the impedance is measured by measuring the current flowing through the first current terminal and the second current terminal.

6. a calculation unit that calculates electrical characteristics according to positions within the biological tissue based on impedances measured from different electrodes and positions of the electrodes; The impedance measuring device of claim 1 , further comprising an image generating unit that generates an image showing electrical characteristics of the living tissue based on the electrical characteristics according to the position.

7. a sample holder on which the biological tissue is placed; The impedance measuring device of claim 1 , further comprising: an upper cover to which at least a portion of the electrodes is fixed and which is disposed on the sample holder.

8. 8. The impedance measuring device of claim 7, wherein the sample holder and the top cover are hinged together to form a clam-shell structure.

9. Step 1: electrically coupling three or more electrodes to biological tissue; a multiplexing circuit selecting and connecting at least some of the electrodes to a first terminal and a second terminal (step 2); measuring the impedance of the biological tissue via the first terminal and the second terminal (step 3); changing an electrode coupled to at least one of the first terminal and the second terminal (step 4); and (step 5) measuring the impedance of the biological tissue via the first terminal and the second terminal.

10. calculating electrical properties according to location within the biological tissue based on the measured impedance and the location of the electrodes; The method of claim 9, further comprising the step of generating an image showing electrical characteristics of biological tissue based on the electrical characteristics according to the position.

Images