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CN-118392961-B - Construction method of flexible wearable electrochromic sensing patch for detecting lactic acid in sweat

CN118392961BCN 118392961 BCN118392961 BCN 118392961BCN-118392961-B

Abstract

The invention belongs to the technical field of wearable sensors, and discloses a construction method of a flexible wearable electrochromic sensing patch for detecting lactic acid in sweat. Comprises the steps of preparing LOX-Ag NDs-C/PET flexible electrode and constructing wearable electrochromic sensing patch based on the flexible electrode. The wearable sensing patch constructed by the invention has the advantages of flexibility, noninvasive property, visualization, reusability and the like. The prepared sensing patch relies on a polyethylene terephthalate PET flexible material, is based on the electrochromic principle of Prussian blue PB, and can realize naked eye semi-quantitative detection through PB fading degree and quantitative detection through color change and current magnitude. After detection, PB color is recovered by using the applied voltage, and the sensor patch is reused. The selected flexible electrode substrate has smaller volume and higher flexibility, avoids the influence of bending and environmental factors on the sensor, improves the application range and stability of the sensor, and reduces the cost and the use condition.

Inventors

  • WEI JIE
  • Sha Junling
  • ZHANG YANING
  • ZHANG HAO
  • WANG MENGJIE

Assignees

  • 江苏大学

Dates

Publication Date
20260512
Application Date
20240410

Claims (10)

  1. 1. A method of constructing a flexible wearable electrochromic sensor patch for detecting lactic acid in sweat, comprising the steps of: step 1, preparing a biological enzyme modified Ag NDs flexible electrode: the method comprises the steps of (1.1) cleaning a flexible polyethylene terephthalate (PET) substrate with ethanol, drying under an infrared lamp, placing the PET substrate under a screen printing template, uniformly dripping conductive carbon paste ink on the screen printing template, uniformly printing with a scraper, and drying and marking as conductive carbon paste substrate C/PET; (1.2) AgNO 3 and KNO 3 powder are dissolved in deionized water, and are magnetically stirred until the AgNO 3 and KNO 3 powder are dissolved to obtain a mixture solution Ag + electrodeposited solution; Dissolving Na 2 HPO 4 and NaH 2 PO 4 in deionized water, fixing the volume by a volumetric flask, regulating the pH value to obtain PBS buffer solution, dispersing lactic acid oxidase in the PBS buffer solution containing BSA, incubating for a period of time, adding polyethylene glycol diglycidyl ether PEGDE, mixing, uniformly dripping on Ag NDs-C/PET, incubating for a period of time, and obtaining a lactic acid oxidase modified Ag NDs flexible electrode which is marked as LOx-Ag NDs-C/PET; step 2, preparing PB flexible electrode: (2.1) cleaning a flexible PET substrate with ethanol, drying under an infrared lamp, then placing the PET substrate under a screen printing template, uniformly dripping conductive silver paste ink on the screen printing template, uniformly printing with a scraper, drying and marking as conductive silver paste substrate Ag/PET; (2.2) dissolving K 3 [Fe(CN) 6 and FeCl 3 powder in deionized water, dropwise adding HCl solution, and magnetically stirring to dissolve to obtain a mixture solution PB electrodeposit solution; (2.3) immersing the conductive silver paste substrate Ag/PET, the platinum wire electrode and the Ag/AgCl electrode into PB electrodeposition liquid, and preparing a PB flexible electrode by a step-by-step voltage method, wherein the PB flexible electrode is named as PB-Ag/PET; step 3, preparation of SiO 2 flexible hydrophobic film: Dissolving hydrophobic SiO 2 powder in absolute ethanol solution, adding perfluorooctyl triethoxysilane, magnetically stirring uniformly, and performing ultrasonic treatment to obtain semitransparent hydrophobic SiO 2 suspension; then, dripping semitransparent hydrophobic SiO 2 suspension liquid on a flexible PET substrate, and uniformly spin-coating for a plurality of times to obtain a SiO 2 flexible hydrophobic film; Step 4, preparation of agarose gel electrolyte: dissolving agarose powder in PBS buffer solution, heating in an oil bath, stirring until the agarose powder is completely dissolved, then dripping the solution on a circular mold, and cooling at room temperature to obtain a circular agarose gel electrolyte which is named AG-gel; step 5, constructing a flexible wearable electrochromic sensing patch: The LOX-Ag NDs-C/PET obtained in the step 1 is punched into a circle by a puncher, and the round LOX-Ag NDs-C/PET is obtained; then, cutting a circle in the PB-Ag/PET obtained in the step 2 to obtain a circular PB-Ag/PET; then, cutting the SiO 2 flexible hydrophobic membrane obtained in the step 3 into a square, and cutting a round shape in the middle to obtain a square round hole SiO 2 flexible hydrophobic membrane; Finally, placing the annular PB-Ag/PET in a round hole of the SiO 2 flexible hydrophobic film, placing LOx-Ag NDs-C/PET in the center of the PB-Ag/PET round hole, and covering AG-gel on the PB-Ag/PET to construct the flexible wearable electrochromic sensing patch.
  2. 2. The construction method according to claim 1, wherein in the step (1.1), The thickness of the flexible PET substrate was 0.05 mm a, The consumption of the conductive carbon paste is 5 mg/cm 3 , the color is matt black, the sheet resistance is 20Ω, the viscosity is 45-Pa s, the fineness is 5 μm, and the temperature resistance is 180 ℃; The doctor blade coating time is 10 s times to 8 times, and the drying condition is that the temperature is 60 ℃ and the drying time is 2 h.
  3. 3. The method according to claim 1, wherein in the step (1.2), the concentration of KNO 3 in the Ag + electrodeposition liquid is 0.1 mol/L, the concentration of AgNO 3 is 0.01 mol/L, the dissolution temperature is 20 ℃, the cyclic voltammetry voltage range is-1 to 0V, the scanning rate is 50 mV/s, and the scanning period is 7.
  4. 4. The construction method according to claim 1, wherein in the step (1.3), The pH value of the PBS buffer solution is 7.40, and the concentration is 0.1 mol/L; The concentration of lactate oxidase dispersed in PBS was 5 mg/mL; BSA was dispersed in PBS at a concentration of 2.5 mg/mL; The PEDGE concentration was 3.8 mg/mL, the incubation temperature was 37℃and the incubation time was 2 h.
  5. 5. The construction method according to claim 1, wherein in the step (2.1), The thickness of the flexible PET substrate was 0.05 mm a, The conductive silver paste is silver gray paste, the dosage is 3 mg/cm 3 , fang Zu is m omega, the viscosity is 10-15 Pa s, the particle size is less than or equal to 10 mu m, the solid content is 57+/-1 wt%, and the temperature resistance is 130 ℃; the doctor blade coating time is 10 s times to 8 times, and the drying condition is that the temperature is 60 ℃ and the drying is 2 h; In the step (2.2), the concentration of K 3 [Fe(CN) 6 in the PB electrodeposition liquid is 0.005 mol/L, the concentration of FeCl 3 is 0.005 mol/L, the concentration of hydrochloric acid is 0.005 mol/L, and the dissolution temperature is 20 ℃; in step (2.3), the step voltage method voltage is 0.3V and the time is 75 s.
  6. 6. The method according to claim 1, wherein in step 3, the concentration of the hydrophobic SiO2 powder in the SiO2 suspension is 12 mg/mL, the concentration of the perfluorooctyl triethoxysilane is 16 mg/mL, the stirring time is 18h, the ultrasonic temperature is 20-30 ℃, and the ultrasonic time is 20-min.
  7. 7. The method according to claim 1, wherein in step 4, the mass ratio of agarose powder to PBS buffer is 0.45 g/15 g, and the oil bath temperature is 130 ℃.
  8. 8. The construction method according to claim 1, wherein, in step 5, The diameter of the round LOx-Ag NDs-C/PET obtained by cutting is 0.6cm, and the area is 9 pi mm 2 ; The inner diameter of the annular PB-Ag/PET ring is 1cm, the outer diameter is 2 cm, and the working area is 0.75 pi cm 2 ; The working area of the square round hole SiO 2 flexible hydrophobic film is (9-pi) cm 2 , and the diameter of the round hole is 2cm; The inner diameter value of the 0cm < PB-Ag/PET circular ring-the diameter value of the circular LOx-Ag NDs-C/PET <1cm.
  9. 9. Use of a flexible wearable electrochromic sensor patch constructed by the construction method of any one of claims 1-8 for detecting lactic acid in sweat.
  10. 10. The use according to claim 9, characterized by the steps of: (1) After lactate oxidase is incubated on the surface of LOx-Ag NDs-C/PET for a period of time, the lactate oxidase and PB-Ag/PET are placed into an electrolytic cell filled with electrolyte together, an electrochemical workstation is used for connecting two electrodes, lactic acid with different concentrations is dripped into the electrolytic cell, a current-time (I-T) signal is collected, and a standard curve is formed by current and time, current and lactic acid concentration, lactic acid concentration and PB-Ag/PET color; Wherein the concentration of lactic acid is 0.25 mmol/L-35 mmol/L, and the detection amount is 50 mu L; (2) In the detection of an actual sweat sample, after the lactate oxidase is incubated on the surface of LOX-Ag NDs-C/PET for a period of time, collecting lactic acid in sweat to the surface of LOX-Ag NDs-C/PET, and generating color change by PB-Ag/PET; (3) And (3) collecting color signals of the sweat sample with unknown lactic acid concentration by adopting the method of the step (2), and substituting the color signals into a PB-Ag/PET color standard curve to obtain the lactic acid concentration in the unknown sweat sample.

Description

Construction method of flexible wearable electrochromic sensing patch for detecting lactic acid in sweat Technical Field The invention belongs to the technical field of wearable sensing, and provides a construction method of a flexible wearable electrochromic sensing patch, and application of the flexible wearable electrochromic sensing patch in rapid and sensitive detection of lactic acid in sweat. Background Lactic acid is an important physiological information substance in sweat, and its content can evaluate the motion state, fatigue degree, metabolism level, etc. of human body. In medicine, excessive accumulation of lactic acid can lead to lactic acidosis, damage to the liver and kidneys, and disruption of the pH balance of the body. Researchers have been working on developing biosensors for lactic acid testing, and many of them are currently under study for urine and blood lactic acid testing, which is inconvenient and invasive, resulting in limited testing conditions and susceptibility to infection. Therefore, there is an urgent need to develop a portable, highly integrated, non-invasive sensor for monitoring the physical condition of the human body. Wearable sensing technology has been widely used in the fields of medical diagnosis, motion monitoring, artificial intelligence, and the like. In recent years, due to the vigorous development of flexible electronic technology, a new development direction is provided for the wearable sensor. The flexible wearable sensor is an electronic device developed by means of flexible electronic technology, can convert biological signals of human body into recordable electric signals in a signal transmission mode, helps human body acquire and analyze various information in the human body, and has the advantages of small volume, High integration level, good biocompatibility, low energy consumption and the like. Compared with the traditional wearable sensor, the flexible wearable sensor has mechanical flexibility and sensing function, can be directly attached to the surface of human skin to realize noninvasive detection, can be implanted into the human body, and can acquire and monitor physiological information of the human body. The wearable electrochromic sensing patch constructed by the invention realizes the visual and semi-quantitative detection of lactic acid by means of electron transfer in redox reaction through Prussian Blue (PB) reduction degree, namely color change degree, within a certain time. After detection, PB color is recovered by externally applying voltage, so that the sensor can be reused. Disclosure of Invention The present invention aims to provide a portable, integrated, reusable, flexible, wearable sensing patch. Based on the catalytic oxidation of lactic acid by lactic acid oxidase, the generated hydrogen peroxide can generate oxidation-reduction reaction with Prussian blue, so that Prussian blue generates color change, and visual and noninvasive sensitive detection of lactic acid in sweat samples is realized. According to the invention, sweat is collected to a silver nano dendrite-carbon paste/polyethylene terephthalate (LOx-Ag NDs-C/PET) electrode chip area modified by lactic acid oxidase through the hydrophilicity of agarose water gel, and redundant sweat can flow out of the sensing device through a SiO 2 flexible hydrophobic film. Due to the specific catalysis of lactic acid oxidase on the round LOX-Ag NDs-C/PET electrode, lactic acid is oxidized into pyruvic acid, and hydrogen peroxide generated by the reaction can react with Prussian blue on the Prussian blue-silver paste/polyethylene terephthalate (PB-Ag/PET) electrode to fade blue Prussian blue (PB red). Visual semi-quantitative detection of lactic acid is realized according to PB reduction degree, namely color change degree, in a certain time. Meanwhile, electron transfer is generated in the oxidation-reduction reaction process, a current output signal is enhanced, and quantitative detection of lactic acid can be realized according to the change of output current and the blue value of a color-changing area. After the detection is finished, the Prussian white is changed back to Prussian blue again through the applied voltage, so that the sensor chip can be reused. The construction method of the flexible wearable electrochromic sensing patch comprises the following steps: step 1, preparing a biological enzyme modified Ag NDs flexible electrode: (1.1) cleaning a flexible polyethylene terephthalate (PET) substrate with ethanol, drying under an infrared lamp, placing the PET substrate under a screen printing template, uniformly dripping conductive carbon paste ink on the screen printing template, uniformly printing with a scraper, drying and marking as C/PET; (1.2) AgNO 3 and KNO 3 powder are dissolved in deionized water, and are magnetically stirred until the AgNO 3 and KNO 3 powder are dissolved to obtain a mixture solution Ag + electrodeposited solution; Dissolving Na 2HPO4 and NaH 2PO4