Continuous microneedle sampling interstitial fluid detection device
By designing a continuous microneedle sampling device, which utilizes microneedle channels and negative pressure chambers to extract interstitial fluid from under the skin, and combining electrochemical detection and microfluidic chips, continuous and rapid detection of interstitial fluid is achieved. This solves the problems of comfort and real-time performance in interstitial fluid detection, and improves the continuity and accuracy of detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANCHANG HANGKONG UNIVERSITY
- Filing Date
- 2025-03-02
- Publication Date
- 2026-04-17
AI Technical Summary
In existing technologies, interstitial fluid detection lacks comfort and real-time performance, making it difficult to achieve continuous and rapid drug concentration detection.
A continuous microneedle sampling interstitial fluid detection device is designed. It uses microneedle channels and negative pressure chambers to draw interstitial fluid from under the skin and performs real-time detection through electrochemical detection electrodes. Combined with microfluidic chips and capillary pumps, it realizes unidirectional flow and evaporation of the liquid, achieving continuous and rapid sampling.
It enables continuous, slow extraction and rapid detection of interstitial fluid, improving the comfort and real-time nature of the detection process, avoiding fluid backflow, and ensuring the continuity and accuracy of the detection.
Smart Images
Figure CN224125950U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of medical testing, and more specifically to a device for continuous microneedle sampling of interstitial fluid. Background Technology
[0002] Drug concentration detection refers to the process of observing drug efficacy during drug treatment by measuring drug concentration in fluids such as blood collected from patients. This allows for the exploration of the drug's in vivo processes, enabling individualized dosing regimens based on the patient's specific condition, guided by fundamental theories of pharmacokinetics and pharmacodynamics. This is achieved through advanced analytical techniques and computer-aided methods, utilizing pharmacokinetic principles and formulas to achieve satisfactory therapeutic effects and avoid toxic side effects.
[0003] Detecting drug concentrations via interstitial fluid is a novel and effective method for drug monitoring. Interstitial fluid is the fluid existing between tissue cells, and it maintains a dynamic equilibrium with blood. Therefore, the concentration of a drug in the interstitial fluid can reflect its distribution within the target tissue. Detecting drug concentrations via interstitial fluid is more comfortable for patients than blood-based methods, and few technologies offer real-time monitoring of drug concentrations within the body. Therefore, a new technology is needed to improve this situation. Utility Model Content
[0004] To address the problems in the prior art, this invention provides a continuous microneedle sampling interstitial fluid detection device that can continuously and rapidly sample and detect interstitial fluid.
[0005] This utility model is implemented through the following technical solution: a continuous microneedle sampling interstitial fluid detection device, including a pressing component, the pressing component having a centrally protruding shape, the centrally protruding pressing component being a resilient pressing component, a pressing cavity being provided inside the centrally protruding shape, a liquid storage tank being tightly connected to the lower edge of the pressing cavity, the lower surface of the liquid storage tank being tightly attached to the upper surface of the electrochemical detection electrode, the liquid storage tank and the electrochemical detection electrode being both annular bodies, a microneedle seat being provided on the lower surface of the electrochemical detection electrode, at least one microneedle tip being embedded inside the microneedle seat, the microneedle tip penetrating the microneedle seat, and each microneedle tip penetrating the interior of the microneedle seat. A microneedle channel is provided, one end of which is open to the outside, and the other end of which is located on the upper surface of the microneedle seat. The pressing element, the liquid reservoir, the electrochemical detection electrode, the microneedle seat, and the microneedle tip are arranged vertically. The upper surface of the microneedle seat, the inner ring wall of the electrochemical detection electrode, and the inner ring wall of the liquid reservoir form a negative pressure cavity. The negative pressure cavity, the pressing cavity, and the inner cavity of the microneedle channel are interconnected. The upper surface of the electrochemical detection electrode contains a detection area and a circuit area. The detection area is located inside the electrochemical detection electrode and above the other end of the microneedle channel.
[0006] The liquid storage tank is equipped with a drainage channel, which is horizontally arranged. The negative pressure chamber is connected to the microfluidic chip through the drainage channel. The microfluidic chip is equipped with a microfluidic channel, which includes a microfluidic channel inlet, a Tesla check valve, a capillary pump, and a microfluidic channel outlet. The negative pressure chamber is connected to the microfluidic channel inlet through the drainage channel. The microfluidic channel inlet is connected to the capillary pump through the Tesla check valve. The capillary pump is connected to the outside through the microfluidic channel outlet.
[0007] When the central protrusion of the pressing element is squeezed, the central protrusion disappears, the pressing cavity disappears, and when the pressing element is released, the pressing element rebounds, the pressing cavity returns to its original state, and the overall cavity formed by the negative pressure cavity and the microneedle channel is in a negative pressure state.
[0008] Furthermore, the electrochemical detection electrode is detachable, specifically insertable, and is a screen-printed electrode.
[0009] Furthermore, the electrochemical signal from the electrochemical detection electrode is received via a mobile terminal.
[0010] Furthermore, the central protrusion of the pressing element is made of polyurethane material.
[0011] Furthermore, the outlet direction of the Tesla check valve forms a 60-degree angle with the liquid flow direction, with an error value of ±1 degree.
[0012] Beneficial effects
[0013] This invention uses a pressing component to create a negative pressure chamber and microneedle channel. Interstitial fluid from beneath the skin is drawn through the microneedle channel onto the surface of the microneedle hub, allowing it to contact the detection area of the electrochemical detection electrode to measure the drug concentration within the fluid. Over a certain period, the interstitial fluid is continuously and slowly extracted. Under the capillary force of the capillary pump, excess fluid is drawn away and discharged through the microfluidic chip to evaporate completely until the next test. Pressing the pressing component again allows for continuous and rapid sampling and detection of the interstitial fluid. Attached Figure Description
[0014] Figure 1 This is a front cross-sectional view of an embodiment of the present invention;
[0015] Figure 2 This is a partial top view of an embodiment of the present invention;
[0016] Figure 3 This is a schematic diagram illustrating the working principle of one embodiment of the present invention.
[0017] Figure 4 This is a structural diagram of a microfluidic chip according to an embodiment of the present invention.
[0018] In the diagram: 1-Pressing element; 1a-Pressing chamber; 2-Reservoir; 2a-Negative pressure chamber; 2b-Drainage channel; 3-Electrochemical detection electrode; 3a-Detection area; 3b-Circuit area; 4-Microneedle seat; 5-Microneedle tip; 5a-Microneedle channel; 6-Microfluidic chip; 6a-Microfluidic channel inlet; 6b-Tesla check valve; 6c-Capillary pump; 6d-Microfluidic channel outlet; 10a-Skin surface; 10b-Interstitial fluid. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0020] A continuous microneedle sampling interstitial fluid 10b detection device, such as Figures 1-4 As shown, the device includes a pressing component 1, which has a centrally protruding shape and is a resilient pressing component 1. A pressing cavity 1a is provided inside the centrally protruding shape. A liquid storage tank 2 is tightly connected to the lower edge of the pressing cavity 1a. The lower surface of the liquid storage tank 2 is tightly attached to the upper surface of the electrochemical detection electrode 3. Both the liquid storage tank 2 and the electrochemical detection electrode 3 are annular. A microneedle seat 4 is provided on the lower surface of the electrochemical detection electrode 3. At least one microneedle tip 5 is embedded inside the microneedle seat 4, penetrating the microneedle seat 4. Each microneedle tip 5 has a microneedle channel 5a penetrating inside, with one end of the microneedle channel 5a communicating with the outside. The other end of 5a is located on the upper surface of the microneedle seat 4. The pressing element 1, the liquid storage tank 2, the electrochemical detection electrode 3, the microneedle seat 4, and the microneedle tip 5 are arranged vertically. The upper surface of the microneedle seat 4, the inner ring wall of the electrochemical detection electrode 3, and the inner ring wall of the liquid storage tank 2 form a negative pressure cavity 2a. The negative pressure cavity 2a, the pressing cavity 1a, and the microneedle channel 5a are interconnected. The upper surface of the electrochemical detection electrode 3 contains a detection area 3a and a circuit area 3b. The detection area 3a is located inside the electrochemical detection electrode 3 and above the other end of the microneedle channel 5a. The above arrangement makes the pressing cavity 1a and the negative pressure cavity 2a form a complete and tight cavity.
[0021] The storage tank 2 has a drainage channel 2b inside, which is arranged horizontally. The negative pressure chamber 2a is connected to the microfluidic chip 6 through the drainage channel 2b. The microfluidic chip 6 has a microfluidic channel, which includes a microfluidic channel inlet 6a, a Tesla check valve 6b, a capillary pump 6c, and a microfluidic channel outlet 6d. The negative pressure chamber 2a is connected to the microfluidic channel inlet 6a through the drainage channel 2b. The microfluidic channel inlet 6a is connected to the capillary pump 6c through the Tesla check valve 6b. The capillary pump 6c is connected to the outside through the microfluidic channel outlet 6d. The above arrangement can prevent liquid backflow at low flow rates, so that the liquid can flow out continuously in one direction. The capillary pump 6c plays the role of providing traction for liquid flow and driving the liquid flow.
[0022] When the central protrusion of the pressing component 1 is squeezed, the central protrusion disappears, and the pressing cavity 1a disappears. As the pressing cavity 1a disappears, when the pressing component 1 is released, the pressing component 1 springs back, and the pressing cavity 1a returns to its original state. As the internal cavity becomes larger, the overall cavity formed by the negative pressure cavity 2a and the microneedle channel 5a is in a negative pressure state.
[0023] In this embodiment, the electrochemical detection electrode 3 is detachable, specifically an insertable type. The electrochemical detection electrode 3 is a screen-printed electrode. Screen-printed electrodes are electrochemical sensors with high sensitivity and high selectivity, used to detect chemical substances in the environment. Based on the principle of interaction between biomolecules and electrodes, they can also be used as biosensors for detecting biomolecules, cells, etc.
[0024] In this embodiment, the electrochemical signal of the electrochemical detection electrode 3 is received by a mobile terminal, and the central protrusion of the pressing part 1 is made of polyurethane material. Polyurethane has good elasticity and can quickly return to its original shape after deformation.
[0025] In this embodiment, the outlet direction of the Tesla check valve 6b forms a 60-degree angle with the liquid flow direction, with an error value of ±1 degree, further preventing liquid backflow at low flow rates.
[0026] In this embodiment, by squeezing the pressing component 1, the negative pressure chamber 2a and the microneedle channel 5a are made into a negative pressure state. The interstitial fluid 10b under the skin surface 10a is drawn through the microneedle channel 5a to the upper surface of the microneedle seat, so that the interstitial fluid 10b comes into contact with the detection area 3a of the electrochemical detection electrode 3 to detect the drug concentration in the interstitial fluid 10b. Over a certain period of time, the interstitial fluid 10b is continuously and slowly extracted. Under the capillary force of the capillary pump, the excess liquid is drawn off and discharged from the body through the microfluidic chip 6 to evaporate until the next detection. Pressing the pressing component 1 again can perform continuous and rapid sampling and detection of the interstitial fluid 10b.
[0027] The working process of this embodiment is as follows:
[0028] 1. Insert the electrochemical detection electrode 3 of this embodiment into the microneedle holder 4 and the liquid reservoir 2, so that the pressing member 1, the liquid reservoir 2, the electrochemical detection electrode 3, and the microneedle holder 4 form a relatively closed cavity, and insert the microneedle tip 5 into the skin surface layer 10a.
[0029] 2. Squeeze the pressing part 1 to make the pressing cavity 1a disappear. The pressing part 1 rebounds and the pressing cavity 1a returns to its original state. As the internal cavity becomes larger, the overall cavity formed by the negative pressure cavity 2a and the microneedle channel 5a is in a negative pressure state.
[0030] 3. Due to negative pressure, the interstitial fluid 10b of the skin surface layer 10a reaches the upper surface of the microneedle seat 4 through the microneedle channel 5a and comes into contact with the detection area 3a of the electrochemical detection electrode 3 connected to the upper surface of the microneedle seat 4, generating an electrochemical signal (drug concentration). The electrical signal is transmitted to the mobile terminal through the circuit area 3b.
[0031] 4. The residual interstitial fluid 10b after detection gathers in the storage tank 2, flows into the inlet of the microfluidic chip 6 through the drainage channel 2b, and then flows out through the Tesla check valve 6b to prevent backflow of liquid at low flow rates, thus enabling the liquid to flow out continuously in one direction. At the same time, the liquid is driven to flow by the capillary pump 6c and discharged through the outlet 6d of the microfluidic channel for evaporation.
[0032] 5. After the interstitial fluid 10b in the microfluidic channel stops flowing, perform the next test. Repeat steps 1-4 to continuously and rapidly sample and test the interstitial fluid 10b.
[0033] The present invention has been described in detail above with reference to its embodiments. Various improvements can be made without departing from the core scope of the present invention, and equivalent components can be used to replace some of its parts. As long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. This specification does not exhaustively describe these combinations, merely for the sake of saving space and resources. Therefore, the protection scope of this invention is not limited to the specific embodiments disclosed herein, but covers all technical solutions falling within the scope of the claims.
Claims
1. A continuous microneedle sampling interstitial fluid detection device, characterized in that The device includes a pressing component, which is centrally convex and is a resilient pressing component. The centrally convex component has a pressing cavity inside. A liquid reservoir is tightly connected to the lower edge of the pressing cavity. The lower surface of the liquid reservoir is tightly fitted to the upper surface of the electrochemical detection electrode. Both the liquid reservoir and the electrochemical detection electrode are annular. A microneedle seat is provided on the lower surface of the electrochemical detection electrode. At least one microneedle tip is embedded inside the microneedle seat, penetrating the microneedle seat. Each microneedle tip has a microneedle channel penetrating its interior. One end of the microneedle channel is open to the outside, and the other end of the microneedle channel is located on the upper surface of the microneedle seat. The pressing element, the liquid reservoir, the electrochemical detection electrode, the microneedle seat, and the microneedle tip are arranged vertically. The upper surface of the microneedle seat, the inner ring wall of the electrochemical detection electrode, and the inner ring wall of the liquid reservoir form a negative pressure cavity. The negative pressure cavity, the pressing cavity, and the inner cavity of the microneedle channel are interconnected. The upper surface of the electrochemical detection electrode contains a detection area and a circuit area. The detection area is located inside the electrochemical detection electrode and above the other end of the microneedle channel. The liquid storage tank is equipped with a drainage channel, which is horizontally arranged. The negative pressure chamber is connected to the microfluidic chip through the drainage channel. The microfluidic chip is equipped with a microfluidic channel, which includes a microfluidic channel inlet, a Tesla check valve, a capillary pump, and a microfluidic channel outlet. The negative pressure chamber is connected to the microfluidic channel inlet through the drainage channel. The microfluidic channel inlet is connected to the capillary pump through the Tesla check valve. The capillary pump is connected to the outside through the microfluidic channel outlet. When the central protrusion of the pressing element is squeezed, the central protrusion disappears, the pressing cavity disappears, and when the pressing element is released, the pressing element rebounds, the pressing cavity returns to its original state, and the overall cavity formed by the negative pressure cavity and the microneedle channel is in a negative pressure state.
2. The device according to claim 1, wherein The electrochemical detection electrode is detachable, specifically an insertable type, and is a screen-printed electrode.
3. The device of claim 1, wherein The electrochemical signal from the electrochemical detection electrode is received via a mobile terminal.
4. The device of claim 1, wherein The central protrusion of the pressing component is made of polyurethane material.
5. The device of claim 1, wherein The outlet direction of the Tesla check valve forms a 60-degree angle with the liquid flow direction, with an error value of ±1 degree.