A antifouling lead ion selective electrode prepared using dendrimer polypeptides

Abstract

The present invention provides an antifouling lead ion selective electrode prepared using dendritic polypeptides, which belongs to the technical field of marine pollution detection. The present invention first electrodeposit polyaniline (PANI) nanowires on a glassy carbon substrate to form a GC / PANI substrate, then prepare MXene nanosheets and composite them with PANI to form GC / PANI-MXene, and then drop lead ion carrier Pb onto the GC / PANI-MXene. 2+ ‑ISM, and finally the electrode surface was modified with dendrimer peptides to obtain GC / PANI‑MXene / Pb 2+ -ISM / pep electrode. The electrode prepared by the present invention can inhibit the adhesion of nonspecific microorganisms and has excellent stability.

Description

Technical Field

[0001] The invention belongs to the technical field of marine pollution detection, and in particular relates to an anti-fouling lead ion selective electrode prepared by using dendritic polypeptides. Background Art

[0002] The inherent toxicity of heavy metals predisposes them to bioaccumulation, particularly in marine ecosystems, making their contamination a major global environmental challenge. Lead, a heavy metal, can severely damage the reproductive system, essential cellular processes, and brain function once it enters the human body through the food chain. Currently, various techniques, including fluorescence spectroscopy, atomic absorption / emission spectroscopy (AAS / AES), and inductively coupled plasma mass spectrometry (ICP-MS), are used to monitor heavy metals. However, these techniques are often time-consuming and require high maintenance. In recent years, ion-selective electrodes (ISEs) have garnered significant attention due to their advantages, including low cost, ease of operation, rapid response, and simplicity. Solid-contact ion-selective electrodes (SC-ISEs), in particular, have demonstrated numerous advantages in ion analysis, including wide applicability, affordability, and portability. However, SC-ISEs still face challenges in terms of potential stability.

[0003] The potential stability of SC-ISE is primarily affected by two factors. First, the performance of the solid conductive layer is directly related to the conversion efficiency between ions and electrons, which can significantly affect the electrode's potential changes in the short term. Second, in long-term testing environments, other contaminants in the sample, such as bacteria and other biological impurities, may form biofilms on the electrode surface, thereby affecting the electrode's potential stability and sensitivity. Therefore, effectively addressing these issues is key to improving the potential stability of SC-ISE. Summary of the Invention

[0004] The object of the present invention is to provide an antifouling lead ion selective electrode prepared by using a dendritic polypeptide, thereby achieving stable and accurate detection of lead ions while preventing fouling.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] First, the present invention provides a method for preparing an antifouling lead ion selective electrode prepared by using a dendritic polypeptide, characterized in that the antifouling lead ion selective electrode is GC / PANI-MXene / Pb 2+ -ISM / PEP electrodes;

[0007] The GC / PANI-MXene / Pb 2+ -The preparation method of ISM / PEP electrode includes the following steps:

[0008] a) Preparation of GC / PANI

[0009] (1) The glassy carbon (GC) substrate was pretreated with alumina slurry and then ultrasonically cleaned in deionized water;

[0010] (2) Electrodeposition of polyaniline (PANI) nanowires in a three-electrode system under constant current;

[0011] (3) After washing with ultrapure water and air-drying, a GC / PANI electrode was obtained;

[0012] b) Preparation of MXene

[0013] (1) MAX (Ti3AlC2) powder was gradually added to the HF solution according to a certain mass-to-volume ratio. After stirring at room temperature, the suspension was centrifuged to obtain a multilayer MXene solid, which was then washed with deionized water to obtain a multilayer MXene.

[0014] (2) The obtained multilayer MXene is dispersed in deionized water, and after ultrasonic treatment, the supernatant obtained by centrifugation is the monolayer MXene;

[0015] c) Preparation of GC / PANI-MXene

[0016] (1) Dropping MXene onto the surface of GC / PANI electrode to obtain GC / PANI-MXene;

[0017] d) Preparation of GC / PANI-MXene / Pb 2+ -ISM;

[0018] (1) dissolving a mixture of polyvinyl chloride (PVC), lead ionophore IV, o-nitrophenyl octyl ether (o-NPOE), and sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) in tetrahydrofuran (THF) and sonicating until completely dissolved to obtain a mixture A;

[0019] (2) Mixture A was added dropwise onto the surface of GC / PANI-MXene and air-dried overnight at a constant temperature and humidity to obtain GC / PANI-MXene / Pb 2+ -ISM electrodes;

[0020] (3) Add the dendrimer peptide solution dropwise to the GC / PANI-MXene / Pb 2+ -ISM electrode surface incubation to obtain GC / PANI-MXene / Pb 2+ -ISM / pep.

[0021] Preferably, the structure of the dendrimer polypeptide is as shown in Formula I.

[0022] Preferably, in step a), the glassy carbon (GC) substrate is pretreated with alumina slurry by sequentially using 1.5 μm, 0.5 μm and 0.05 μm alumina slurries to pretreat the glassy carbon (GC) substrate;

[0023] The constant current is 0.004 mA cm -2 The constant current of the electroplating polyaniline nanowires was 1 h.

[0024] Preferably, in step b), the mass volume ratio of the MAX powder to the HF solution is 1 g:10 mL, the concentration of the HF solution is 40% wt%, the stirring time at room temperature is 18 h, and the completion criterion for the deionized water washing is that the pH value of the deionized water is ≥6;

[0025] The ultrasonic treatment time is 1 h.

[0026] Preferably, in step c), 5 μL of MXene is dropped onto the surface of each GC / PANI electrode.

[0027] Preferably, in the step d), the mass volume ratio of the polyvinyl chloride, the lead ion carrier IV, the o-nitrophenyl octyl ether o-NPOE and the sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) to tetrahydrofuran (THF) is 87.5 mg:3.5 mg:157.5 mg:1.5 mg:2 mL;

[0028] The amount of the mixture A added dropwise to the GC / PANI-MXene surface was 90 μL;

[0029] The amount of the dendritic polypeptide solution added was 10 μL, the concentration of the dendritic polypeptide solution was 0.02 mol / L, and the dendritic polypeptide was 2+ -The incubation time of the ISM electrode surface was 10 hours.

[0030] Preferably, the anti-fouling of the anti-fouling lead ion selective electrode refers to anti-bacterial contamination.

[0031] Secondly, the present invention provides an antifouling lead ion selective electrode prepared by using a dendrimer polypeptide, characterized in that the antifouling lead ion selective electrode is prepared by the above-mentioned preparation method.

[0032] Secondly, the present invention provides a dendrimer polypeptide for inhibiting bacterial contamination, wherein the structure of the dendrimer polypeptide is shown in formula (I).

[0033] Preferably, the bacteria are Escherichia coli and Staphylococcus aureus.

[0034] A dendrimer polypeptide is used in the preparation of an electrode for inhibiting bacterial contamination. The structure of the dendrimer polypeptide is shown in formula (I).

[0035] Preferably, the bacteria are Escherichia coli and Staphylococcus aureus.

[0036] The beneficial effects of the present invention are:

[0037] The present invention provides a novel lead ion selective electrode based on antifouling dendritic polypeptide for detecting lead ions in complex samples. The dendritic polypeptide provided by the present invention has the characteristics of high hydration and relative conformational entropy, which can effectively inhibit the adhesion of non-specific microorganisms. At the same time, the present invention utilizes the synergistic effect between polyaniline nanowires and MXene nanosheets to improve the ion-electron conversion rate, thereby improving the electrochemical stability of the electrode prepared by the present invention. Secondly, the electrode prepared by the present invention has good electrochemical stability and can respond quickly to changes in potential within 1s. Under the conditions of storage in bacterial solution, the electrode after incubation with the polypeptide maintains its Nernst response slope without significant change for up to 6 days. In addition, the electrode prepared by the present invention has a good electrochemical stability to O 2、 CO 2、 It is N2 and light insensitive, making it suitable for the analysis of practical and complex samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 : SEM morphologies of (a) MAX, (b) monolayer MXene, (c) PANI nanowires, and (d) PANI-MXene, and TEM image and (f) HR-TEM image of (e) monolayer MXene.

[0039] Figure 2 : (a) GC / PANI-MXene, GC / PANI, and GC / MXene in 1 M HClO4 aqueous solution at 100 mV s -1 (a) Cyclic voltammetry curves and (b) impedance spectra of each electrode;

[0040] Figure 3 : Molecular dynamics simulation results of lead ion adsorption on the peptide interface, where (a) is the three-dimensional density map before adsorption, (b) is the three-dimensional density map after adsorption, (c) is the mean square displacement map of lead ions, and (d) is the radial distribution function between Pb and N in the peptide;

[0041] Figure 4 :(a) Escherichia coli growth curve, (b) Staphylococcus aureus growth curve, (c) Escherichia coli plate count experiment image, (d) Staphylococcus aureus plate count experiment image;

[0042] Figure 5:(a) Detection limit of different electrodes, (b) response time of different electrodes;

[0043] Figure 6 :(a) Chronopotential stability of different electrodes, (b) Water layer test of different electrodes; (c) GC / PANI-MXene / Pb 2+ -ISM and GC / PANI-MXene / Pb 2+ -Nernst response slope of ISM / pep electrode during long-term testing; (d) GC / PANI-MXene / Pb 2+ -ISM and GC / PANI-MXene / Pb 2+ -Selective detection results of ISM / pep electrode; (e) O2, CO2, N2 and light on GC / PANI-MXene / Pb 2+ -ISM / pep sensitivity test results; (f) pH for GC / PANI-MXene / Pb 2+ -Test results affected by ISM / PEP sensitivity;

[0044] Figure 7 :GC / PANI-MXene / Pb 2+ - Repeatability (a) and reproducibility test results (b) of ISM / pep;

[0045] Figure 8 :GC / PANI-MXene / Pb 2+ -The antibacterial effect of ISM / pep electrode under real seawater conditions, where a is Escherichia coli and b is Staphylococcus aureus. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below in conjunction with specific embodiments. The examples provided are only for illustrating the present invention and are not intended to limit the scope of the present invention. The examples provided below can serve as a guide for further improvements by those skilled in the art and are not intended to limit the present invention in any way.

[0047] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples, unless otherwise specified, were all commercially available.

[0048] The dendrimer polypeptide used in the present invention is DOPA(KE)4(KE)2KEPPPP-DOPA, and its chemical structure is shown in Formula I:

[0049]

[0050] The materials used in the present invention are as follows:

[0051] Lead ionophore IV, 2-nitrophenyloctyl ether (o-NPOE), sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and polyvinyl chloride (PVC) were purchased from Sigma. MAX(Ti3AlC2), aniline, HF, and HClO4 were purchased from Sinopharm. The peptide DOPA(KE)4(KE)2KEPPPP-DOPA was synthesized by Suzhou Xiuxiu Biotechnology Co., Ltd. Ultrapure water with a specific resistance of 18.2 MΩcm was prepared using an OMNI water purification system.

[0052] The instruments used in the present invention are as follows:

[0053] All potential measurements in the present invention were performed using a conventional three-electrode cell system and a P4000 (Princeton) electrochemical workstation.

[0054] In 1 M HClO4, the scan rate was 100 mV s -1 , CV tests were performed at a cycling potential between -0.2 and 1.0 V (vs. SCE).

[0055] Electrochemical impedance spectroscopy (EIS) was obtained on an Autolab station (Metrohm) with the following experimental parameters: frequency range 100 kHz to 0.1 Hz, amplitude 10 mV.

[0056] In 10 -3 The chronopotentiometry was performed in a 1 M Pb(NO3)2 solution with a reverse current (±1 nA) for 120 s.

[0057] The morphology of the solid transduction layer was observed using a field emission scanning electron microscope (S-4800, Hitachi, Japan).

[0058] The film quality of the solid conductive layer was measured using an Autolab EQCM electrochemical quartz crystal microbalance (Metrohm).

[0059] The masses of PANI and PANI-MXene were measured by EQCM to be 5.3 μg and 5.8 μg, respectively. The mass of MXene was calculated to be 8 μg.

[0060] The online growth curves of bacteria were obtained using a microbial growth analyzer equipped with a 32-channel capacitively coupled contactless conductivity detector (Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences).

[0061] Example 1

[0062] a) Preparation of GC / PANI

[0063] (1) The glassy carbon (GC) substrate was pretreated with 1.5 μm, 0.5 μm, and 0.05 μm alumina slurries, followed by three ultrasonic cleanings in deionized water;

[0064] (2) At 0.004 mA cm -2 Polyaniline nanowires were electrodeposited in a three-electrode system with a glassy carbon electrode as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode under a constant current of 1 h.

[0065] (3) After washing with ultrapure water and air-drying, a GC / PANI electrode was obtained;

[0066] b) Preparation of MXene

[0067] (1) 1.0 g of MAX (Ti3AlC2) powder was gradually added to 10 mL of HF solution (40 wt%). After stirring at room temperature for 18 h, the suspension was separated by centrifugation to obtain a multilayer MXene solid. The multilayer MXene solid was then washed with deionized water several times until the pH value of the deionized water was ≥6.

[0068] (2) The resulting multilayer MXene was dispersed in deionized water and sonicated for 1 hour. The mixture was centrifuged at approximately 3500 rpm to obtain a dark supernatant, which is the monolayer MXene.

[0069] c) Preparation of GC / PANI-MXene

[0070] (1) Drop 5 μL of MXene onto the surface of the GC / PANI electrode to obtain GC / PANI-MXene;

[0071] d) Preparation of GC / PANI-MXene / Pb 2+ -ISM

[0072] (1) A mixture of 87.5 mg of polyvinyl chloride (PVC), 3.5 mg of lead ionophore IV, 157.5 mg of o-nitrophenyl octyl ether (o-NPOE), and 1.5 mg of sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) was dissolved in 2.0 mL of tetrahydrofuran (THF) and sonicated until completely dissolved to obtain mixture A;

[0073] (2) 90 μL of mixture A was added dropwise to the GC / PANI-MXene surface and air-dried overnight at a constant temperature and humidity to obtain GC / PANI-MXene / Pb 2+ -ISM electrodes;

[0074] (3) 10 μL of 0.02 mol / L dendrimer peptide was added dropwise to the GC / PANI-MXene / Pb 2+ -ISM electrode surface was incubated for 10 h to obtain GC / PANI-MXene / Pb 2+ -ISM / pep.

[0075] Comparative Example 1 Preparation of GC / PANI-MXene / Pb 2+ -ISM electrode

[0076] a) Preparation of GC / PANI

[0077] (1) The glassy carbon (GC) substrate was pretreated with 1.5 μm, 0.5 μm, and 0.05 μm alumina slurries, followed by three ultrasonic cleanings in deionized water;

[0078] (2) At 0.004 mA cm -2 Polyaniline (PANI) nanowires were electrodeposited in a three-electrode system at a constant current of 1 h.

[0079] (3) After washing with ultrapure water and air-drying, a GC / PANI electrode was obtained;

[0080] b) Preparation of MXene

[0081] (1) 1.0 g of MAX (Ti3AlC2) powder was gradually added to 10 mL of HF solution (40 wt%), and then stirred at room temperature for 18 h. The suspension was separated by centrifugation to obtain a multilayer MXene solid, which was then washed with deionized water several times until the pH value of the deionized water was ≥6 to obtain a multilayer MXene;

[0082] (2) The resulting multilayer MXene was dispersed in deionized water and sonicated for 1 hour. The mixture was centrifuged at approximately 3500 rpm to obtain a dark supernatant, which is the monolayer MXene.

[0083] c) Preparation of GC / PANI-MXene

[0084] (1) Drop 5 μL of MXene onto the surface of the GC / PANI electrode to obtain GC / PANI-MXene;

[0085] d) Preparation of GC / PANI-MXene / Pb 2+ -ISM

[0086] (1) A mixture of 87.5 mg of polyvinyl chloride (PVC), 3.5 mg of lead ionophore IV, 157.5 mg of o-nitrophenyl octyl ether (o-NPOE), and 1.5 mg of sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) was dissolved in 2.0 mL of tetrahydrofuran (THF) and sonicated until completely dissolved to obtain mixture A;

[0087] (2) 90 μL of mixture A was added dropwise to the surface of the GC / PANI-MXene electrode and air-dried overnight at a constant temperature and humidity to obtain GC / PANI-MXene / Pb 2+ -ISM electrodes.

[0088] Comparative Example 2 Preparation of GC / PANI / Pb 2+ -ISM electrode

[0089] a) Preparation of GC / PANI

[0090] (1) The glassy carbon (GC) substrate was pretreated with 1.5 μm, 0.5 μm, and 0.05 μm alumina slurries, followed by three ultrasonic cleanings in deionized water;

[0091] (2) At 0.004 mA cm -2 Polyaniline nanowires were electrodeposited in a three-electrode system at a constant current of 1 h.

[0092] (3) After washing with ultrapure water and air-drying, a GC / PANI electrode was obtained;

[0093] b) Preparation of GC / PANI / Pb 2+ -ISM electrode

[0094] (1) A mixture of 87.5 mg of polyvinyl chloride (PVC), 3.5 mg of lead ionophore IV, 157.5 mg of o-nitrophenyl octyl ether (o-NPOE), and 1.5 mg of sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) was dissolved in 2.0 mL of tetrahydrofuran (THF) and sonicated until completely dissolved to obtain mixture A;

[0095] (2) 90 μL of mixture A was added dropwise to the surface of the GC / PANI electrode and air-dried overnight at a constant temperature and humidity to obtain GC / PANI / Pb 2+ -ISM electrode.

[0096] Comparative Example 3 Preparation of GC / MXene / Pb 2+ -ISM electrode

[0097] a) Preparation of GC / MXene electrodes

[0098] (1) The glassy carbon (GC) substrate was pretreated with 1.5 μm, 0.5 μm, and 0.05 μm alumina slurries, followed by three ultrasonic cleanings in deionized water;

[0099] (2) 1.0 g of MAX (Ti3AlC2) powder was gradually added to 10 mL of HF solution (40 wt%), and then stirred at room temperature for 18 h. The suspension was separated by centrifugation to obtain a multilayer MXene solid, which was then washed with deionized water several times until the pH value of the deionized water was ≥6 to obtain a multilayer MXene;

[0100] (3) The resulting multilayer MXene was dispersed in deionized water and sonicated for 1 hour. The mixture was centrifuged at approximately 3500 rpm to obtain a dark supernatant, which is the monolayer MXene.

[0101] (4) 8 μL of MXene was dropped onto the GC after ultrasonic cleaning to obtain a GC / MXene electrode;

[0102] B) Preparation of GC / MXene / Pb 2+ -ISM electrode

[0103] (1) A mixture of 87.5 mg of polyvinyl chloride (PVC), 3.5 mg of lead ionophore IV, 157.5 mg of o-nitrophenyl octyl ether (o-NPOE), and 1.5 mg of sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) was dissolved in 2.0 mL of tetrahydrofuran (THF) and sonicated until completely dissolved to obtain mixture A;

[0104] (2) 90 μL of mixture A was added dropwise to the surface of the GC / MXene electrode and air-dried overnight at a constant temperature and humidity to obtain GC / MXene / Pb 2+ -ISM electrode.

[0105] Comparative Example 4 Preparation of GC / Pb 2+ -ISM

[0106] (1) The glassy carbon (GC) substrate was pretreated with 1.5 μm, 0.5 μm, and 0.05 μm alumina slurries, followed by three ultrasonic cleanings in deionized water;

[0107] (2) A mixture of 87.5 mg of polyvinyl chloride (PVC), 3.5 mg of lead ionophore IV, 157.5 mg of o-nitrophenyl octyl ether (o-NPOE), and 1.5 mg of sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) was dissolved in 2.0 mL of tetrahydrofuran (THF) and sonicated until completely dissolved to obtain a mixture A;

[0108] (3) 90 μL of mixture A was added dropwise to the surface of the GC electrode and air-dried overnight at a constant temperature and humidity to obtain GC / Pb 2+ -ISM electrode.

[0109] Example 2 Characterization of PANI-MXene

[0110] The morphologies of MAX, monolayer MXene, PANI nanowires, and PANI-MXene composite films were examined using SEM.

[0111] The TEM and HR-TEM images of the monolayer MXene were detected using transmission electron microscopy, and the results were as follows: Figure 1 shown.

[0112] exist Figure 1 The SEM image of MAX after strong hydrofluoric acid etching is as follows: Figure 1 ab, indicating that the Al layer was removed. In addition, after ultrasonic-assisted solvent stripping, the thick MXene layer was stripped into a single layer structure ( Figure 1 b), indicating the successful preparation of two-dimensional MXene nanosheets. The polyaniline film obtained by electrodeposition polymerization showed a randomly oriented nanowire structure ( Figure 1 c). For PANI-MXene complex ( Figure 1 d), it can be seen that MXene is tightly covered on the PANI nanowires due to the interaction between the Tx groups (-O, -OH, -F) and PANI. In addition, transmission electron microscopy clearly confirms the successful preparation of a single-layer MXene. The lattice spacing of the (1 1 0) plane estimated by HR-TEM is This is consistent with the Ti3C2MXene lattice size reported in the literature.

[0113] Example 3 CV and impedance performance testing of PANI-MXene composite materials

[0114] In 1 M HClO4, the scan rate was 100 mV s -1 , CV tests were performed on GC / PANI-MXene, GC / PANI, and GC / MXene at a cycling potential between -0.2 and 1.0 V (vs. SCE);

[0115] The results obtained are as follows Figure 2 As shown in Figure a, the CV curve clearly shows two pairs of redox peaks, which are due to the continuous redox reduction of the cyanide emeraldine to emeraldine salt and then to the fully nitrided emeraldine, thus clarifying the intrinsic redox process of polyaniline in different conductive states.

[0116] Mass specific capacitance (C,F g -1) was further quantified using the following formula:

[0117]

[0118] ΔV is the potential window, m is the total mass of the electroactive material, A is the integrated area under the CV curve, and k is the scan rate. The results show that the specific capacitance of the PANI-MXene hybrid material increased by 56.5F g-1, exceeding that of the individual PANI nanowires (492F g-1) and MXene (213.4F g-1). Figure 2 b shows the Nyquist plots of electrodes composed of GC / PANI-MXene, GC / PANI, and GC / MXene, and the related equivalent circuit models are shown in Figure 5. Figure 2 As shown in the insert of b.

[0119] The electrochemical impedance spectroscopy data of different electrodes are summarized in Table 1.

[0120] Table 1 Electrochemical impedance spectroscopy performance of GC / PANI-MXene, GC / PANI and GC / MXene

[0121]

[0122] from Figure 2 b and Table 1, the charge transfer resistance (Rct) of the PANI-MXene composite material is 0.82 Ω cm 2 , which is significantly lower than the 1.18Ωcm of polyaniline. 2 The CV and impedance results demonstrate that the introduction of MXene into the solid transduction layer significantly enhances the specific capacitance and promotes the ion-electron transfer kinetics, thus indicating that the synergistic interactions within the composite material are beneficial for electrochemical applications.

[0123] Example 4 Results of Lead Ion Transport in Antifouling Coatings

[0124] The present invention used molecular dynamics (MD) simulations using the massively parallel atomic / molecular simulation software (LAMMPS23) to characterize the transport of lead ions through the dendrimer peptide coating. Throughout the dynamics simulations, an all-atom force field (OPLS-AA) was employed to accurately describe the interactions between atoms.

[0125] The results obtained are as follows Figure 3 As shown, Figure 3Figures ab show three-dimensional density plots, where the color scale on the right illustrates the relative density of lead ions. Before adsorption, the predominantly blue color is observed, with instances of green and red, indicating regions of insufficient ion concentration, thereby indicating minimal interaction with the peptide interface or dispersion within the solution. Higher red and green colors likely represent regions of higher ion concentration, perhaps in the bulk solution above the peptide layer. After adsorption, blue stripes appear along the z-axis, alternating between green and red stripes, indicating that lead ions adsorb at discrete sites on the peptide interface, reflecting the distribution of preferential binding sites on the peptide. The adsorption process is heterogeneous, with some regions having a greater affinity for lead ions than others.

[0126] Figure 3 c depicts the mean square displacement (MSD), which depicts the time gradient diffusion of lead ions at the peptide interface. The linear series represents the diffusion motion, and the diffusion coefficient is derived as This coefficient provides a measure of the speed with which lead ions traverse the peptide environment.

[0127] Figure 3 d shows the radial distribution function (RDF) between the lead ion (Pb) and the nitrogen atom (N) within the peptide framework. The initial acute peak indicates the optimal distance for the Pb-N atomic interaction, indicating that a strong interaction or binding occurs at this binding site.

[0128] Computational simulations revealed that lead ions exhibit favorable adsorption-desorption kinetics at the dendrimer-peptide interface, accompanied by efficient diffusion and ultimately successful transmembrane movement through the peptide structure.

[0129] Example 5 Testing the Antifouling Performance of Dendrimer Polypeptide Modified Electrodes

[0130] (1) Different modified interfaces are placed at 10 6 The cells were immersed in bacterial suspensions of Escherichia coli and Staphylococcus aureus (CFU mL-1) for 24 h and then placed in test tubes filled with LB broth. All test tubes were then inserted into the CCS simultaneously.

[0131] (2) Using a 32-channel non-contact conductivity sensor, the growth dynamics of microorganisms on different electrode surfaces were monitored in real time and sensitively. The results were as follows: Figure 4 As shown in ab;

[0132] It can be seen from the figure that when the inoculation concentration is 10 6 CFU mL -1Under the control conditions, s-shaped curves were obtained for both peptide-incubated and non-incubated electrodes. Notably, when the electrode surface incubated with peptides was immersed in the bacterial solution, the microbial growth curves of Escherichia coli and Staphylococcus aureus showed a relatively long lag phase compared to the unincubated electrode. In addition, the onset of the exponential growth phase, representing the rapid growth phase, was delayed. The exponential phase was followed by a deceleration phase and transitioned to a stationary phase, during which the normalized apparent conductivity value (NACV) on the peptide-incubated electrode was relatively low. These microbial growth kinetics data indicate that the peptide-modified surface can effectively reduce the formation of biofilms and inhibit the adhesion of microorganisms to the electrode surface.

[0133] The colony growth of Escherichia coli and Staphylococcus aureus was detected by plate counting method. 6 CFU mL -1 The membrane surface was immersed in the bacterial solution of Escherichia coli and Staphylococcus aureus for 12 hours, and then rinsed with 1000μL PBS solution. The PBS bacterial solution after rinsing was mixed with sterile water in a certain ratio (1:50 for Escherichia coli and 3:200 for Staphylococcus aureus) and then coated on the surface dish and cultured. The results were as follows Figure 4 cd shown.

[0134] The peptide-modified surface exhibited minimal bacterial growth, demonstrating the peptide layer's excellent antifouling properties, effectively reducing bacterial adhesion and proliferation. The peptide layer also demonstrated significant antifouling activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, demonstrating the broad potential of the dendrimer peptides provided by this invention in preventing bacterial contamination.

[0135] Example 6 Detecting the Potential Response Level of Electrodes

[0136] The potential test of the electrodes prepared in Example 1 and Comparative Examples 1-4 was carried out in a series of Pb(NO3)2 solutions with gradient concentrations. The results are shown in FIG. Figure 5 shown.

[0137] Figure 5 a shows that GC / PANI-MXene / Pb 2+ -ISM in Pb 2+ Concentration range (10 -8 ~10 -3 The response is linear within the range of 100 mV and the Nernstian slope is approximately -29.4 mV dec. -1 , which is within the expected theoretical range for divalent ions. 2+ -ISM、GC / PANI / Pb 2+ -ISM and GC / MXene / Pb 2+-ISM, this electrode structure has a wider linear range and lower detection limit. In particular, GC / PANI-MXene / Pb 2+ -ISM showed an extremely low detection limit of 1.99 nM, indicating the effective synergistic effect between PANI and MXene, and its sensitivity was higher than that of GC / PANI / Pb 2+ The ISM was improved by nearly two orders of magnitude. Moreover, the detection capability was largely preserved after applying the peptide antifouling coating, with the detection limit increasing from 1.99 nM to 3.16 nM.

[0138] exist Figure 5 b, GC / PANI-MXene / Pb 2+ -ISM and GC / PANI-MXene / Pb 2+ -ISM / pep immersed in a series of Pb 2+ In solution, the stable potential is reached within 1s. GC / MXene / Pb 2+ -ISM and GC / PANI / Pb 2+ -ISM's response time is extended to less than 10s. In contrast, GC / Pb 2+ -ISM takes 20 seconds to several minutes to reach a steady state. GC / PANI-MXene / Pb 2+ The rapid response of the -ISM ​​can be attributed to the large specific capacitance and low charge transfer resistance of PANI-MXene. In addition, the presence of the peptide antifouling layer does not affect the electrode's ability to rapidly stabilize potential.

[0139] Therefore, the GC / PANI-MXene / Pb prepared in the present invention 2+ -ISM / pep exhibits considerable advantages in response time and detection range, demonstrating its great potential in the fields of analysis and detection.

[0140] Example 7

[0141] In 10 -3 The electrodes prepared in Example 1 and Comparative Examples 1-4 were subjected to chronopotentiometry in a Pb(NO3)2 solution of 100 M at a reverse current (±1 nA) for 120 s. The results are shown in FIG. Figure 6 a and 7b.

[0142] from Figure 6 As can be seen from a and 7b, GC / PANI-MXene / Pb 2+ -The potential drift of the ISM is only 5.0 μV s -1 This shows that at a current of ±1nA, GC / PANI / Pb 2+ -ISM(51.6μV s -1)、GC / MXene / Pb 2+ -ISM(76.7μV s -1 ) and GC / Pb 2+ -ISE(705.5μV s -1 ) has significantly improved. After incubation with the peptide, the potential drift remains at 5.0 μV s -1 No significant changes within .

[0143] The low-frequency capacitance of solid contacts is calculated using the formula ΔE / Δt=I / C. GC / PANI-MXene / Pb 2+ -ISM and its peptide-cultured electrode (GC / PANI-MXene / Pb 2+ -ISM / pep) has a capacitance (C) value of 200μF. This is much higher than GC / PANI / Pb 2+ -ISM (19.4μF) and GC / MXene / Pb 2+ -ISM (13.1μF). These results demonstrate the efficacy of the PANI-MXene composite in enhancing the low-frequency capacitance, thereby improving the 2+ -ISE has a higher potential stability and is superior to either PANI or MXene when used alone.

[0144] like Figure 6 As shown in b, GC / PANI-MXene / Pb 2+ -ISM and its peptide-bound counterpart GC / PANI-MXene / Pb 2+ -ISM / pep showed remarkable stability in the water layer test without obvious potential drift. In contrast, GC / PANI / Pb 2 + -ISM and GC / MXene / Pb 2+ -ISM has a smaller potential drift. It is worth noting that in GC / Pb 2+ These observations suggest that the integration of the PANI-MXene composite as a solid transduction layer effectively mitigates the formation of the detrimental water layer.

[0145] Next, to evaluate the example GC / PANI-MXene / Pb 2+ -ISM / PEP and GC / PANI-MXene / Pb 2+ -Long-term stability of ISMs, immersing them in a concentration of 10 4 CFU mL -1 The electrode was periodically recovered and its Nernst response slope in lead nitrate solution was measured. The results were as follows: Figure 6 As shown in c.

[0146] As can be seen from the figure, the Nernst slope of the electrode without the peptide antifouling layer dropped significantly after three days. In contrast, the electrode treated with the peptide antifouling layer maintained a consistent Nernst response slope over six days, even in bacterial solution. These results demonstrate that the peptide has excellent antifouling properties and that the long-term stability of the electrode is significantly improved after peptide incubation.

[0147] Evaluation of GC / PANI-MXene / Pb by separation solution method 2+ -ISM / PEP and GC / PANI-MXene / Pb 2+ -ISM electrode selectivity, select K + 、Cd 2+ , Ca 2+ 、Na + Mg 2+ 、H + 、Cu 2+ and Zn 2+ As interfering ions, the results obtained are as follows Figure 6 As shown in d.

[0148] As can be seen from the figure, GC / PANI-MXene / Pb 2+ -ISM and GC / PANI-MXene / Pb 2+ -ISM / pep both showed excellent selectivity, indicating that peptide incubation did not affect the selectivity of the lead ion selective electrode.

[0149] In 10 -3 Pb(NO3)2 was bubbled continuously for a period of time and then purged to test the effects of O2, CO2 and N2 on GC / PANI-MXene / Pb 2+ -Sensitivity of ISE / PEP potential response, the results obtained are as follows Figure 6 As shown in e.

[0150] As can be seen from the figure, no obvious potential change was observed during the 1 hour measurement. -3 The response of the electrode potential in M ​​Pb(NO3)2 was studied to study the effect of light. Similarly, no obvious potential drift was found in this process, indicating that GC / PANI-MXene / Pb 2+ -ISE is insensitive to interference from O2, CO2, N2 and light.

[0151] The pH was adjusted by HNO3 or NaOH in the range of pH 1.5 to 11.0. 2+-ISM and GC / PANI-MXene / Pb 2+ -ISM / pep explored pH sensitivity and the results were as follows Figure 6 As shown in f.

[0152] As can be seen from the figure, the electrode potential shows remarkable stability and remains stable in the pH range of 3.0 to 9.0, with fluctuations strictly limited to ±1.8mV, which is negligible. - and H + The potential difference only appears when the pH exceeds 9.0 or is lower than 3.0. In conclusion, the Pb 2+ -ISEs, which showed good and effective operation ability in a wide pH range, further demonstrated the potential of the electrodes prepared by the present invention in various analytical applications.

[0153] Next, the present invention is in 10 -3 The reproducibility and repeatability of the electrode prepared in Example 1 were tested in a Pb(NO3)2 solution of 100 M with a reverse current (±1 nA) for 120 s. The test results are shown in FIG. Figure 7 shown.

[0154] from Figure 7 It can be seen that GC / PANI-MXene / Pb 2+ -ISM / pep has good reproducibility and repeatability over its service life.

[0155] Example 8 Detection of GC / PANI-MXene / Pb prepared by the present invention 2+ -Actual detection effect of ISM / pep electrode

[0156] GC / PANI-MXene / Pb prepared by the present invention 2+ -ISM / pep electrode was used to test three groups of experimental wastewater samples using direct potentiometric method, and each sample was tested three times in parallel;

[0157] The control group was detected by inductively coupled plasma atomic emission spectroscopy (ICP-AES) technology, and the results are shown in Table 2.

[0158] Table 2 Pb in three actual experimental wastewater samples determined by direct potentiometry and ICP-AES 2+ concentration

[0159]

[0160] As can be seen from Table 1, the GC / PANI-MXene / Pb2+ The results obtained by direct potentiometry (ISM / PEP) are in good agreement with those obtained by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0161] Afterwards, the present invention cultured Escherichia coli and Staphylococcus aureus under seawater conditions, immersed the electrode in the above bacterial solution for 12 hours, and coated the culture dish with the bacterial solution after diluting it with seawater to detect the GC / PANI-MXene / Pb 2+ -The antibacterial effect of ISM / pep electrode under real seawater conditions, the results are as follows Figure 8 shown.

[0162] from Figure 8 It can be seen that GC / PANI-MXene / Pb 2+ -ISM / pep electrode can effectively inhibit Escherichia coli and Staphylococcus aureus.

Claims

1. A method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide, characterized in that: The antifouling lead ion selective electrode is GC / PANI-MXene / Pb 2+ -ISM / PEP electrodes; The GC / PANI-MXene / Pb 2+ -The preparation method of ISM / PEP electrode includes the following steps: a) Preparation of GC / PANI (1) The glassy carbon (GC) substrate was pretreated with alumina slurry and then ultrasonically cleaned in deionized water; (2) Electrodeposition of polyaniline (PANI) nanowires in a three-electrode system under constant current; (3) After washing with ultrapure water and air drying, a GC / PANI electrode was obtained; b) Preparation of MXene (1) MAX powder was gradually added to HF solution at a certain mass-to-volume ratio. After stirring at room temperature, the suspension was centrifuged to obtain multilayer MXene solid, which was then washed with deionized water to obtain multilayer MXene. Wherein, the MAX powder is Ti3AlC2 powder; (2) The obtained multilayer MXene is dispersed in deionized water, and after ultrasonic treatment, the supernatant obtained by centrifugation is the single-layer MXene; c) Preparation of GC / PANI-MXene (1) Dropping MXene onto the surface of GC / PANI electrode to obtain GC / PANI-MXene; d) Preparation of GC / PANI-MXene / Pb 2+ -ISM; (1) A mixture of polyvinyl chloride (PVC), lead ion carrier IV, o-nitrophenyl octyl ether (o-NPOE) and sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) was dissolved in tetrahydrofuran (THF) and ultrasonicated until completely dissolved to obtain a mixture A; (2) Mixture A was added dropwise onto the surface of GC / PANI-MXene and air-dried overnight at a constant temperature and humidity to obtain GC / PANI-MXene / Pb 2+ -ISM electrodes; (3) Add the dendrimer peptide solution dropwise to the GC / PANI-MXene / Pb 2+ -ISM electrode surface incubation to obtain GC / PANI-MXene / Pb 2+ -ISM / pep.

2. The method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide according to claim 1, characterized in that: The structure of the dendrimer polypeptide is shown in formula (I): Formula (I).

3. The method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide according to claim 1, characterized in that: In step a), the glassy carbon (GC) substrate is pretreated with alumina slurry by sequentially using 1.5 μm, 0.5 μm and 0.05 μm alumina slurries to pretreat the glassy carbon (GC) substrate; The constant current is 0.004 mA cm −2 The constant current of the electroplating polyaniline nanowires was 1 h.

4. The method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide according to claim 1, wherein: In step b), the mass volume ratio of the MAX powder to the HF solution is 1 g:10 mL, the concentration of the HF solution is 40 wt %, the stirring time at room temperature is 18 h, and the deionized water washing is completed when the pH value of the deionized water is ≥6; The ultrasonic treatment time is 1 h.

5. The method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide according to claim 1, characterized in that: In the step c), 5 μL of MXene is dropped onto the surface of each GC / PANI electrode.

6. The method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide according to claim 1, characterized in that: In the step d), the mass volume ratio of the polyvinyl chloride, the lead ion carrier IV, the o-nitrophenyl octyl ether (o-NPOE), and the sodium 4-[3,5-2(trifluoromethyl)phenyl]borate (NaTFPB) to tetrahydrofuran (THF) is 87.5 mg: 3.5 mg: 157.5 mg: 1.5 mg: 2 mL; The amount of the mixture A added dropwise to the GC / PANI-MXene surface was 90 μL; The amount of the dendritic polypeptide solution added was 10 μL, the concentration of the dendritic polypeptide solution was 0.02 mol / L, and the dendritic polypeptide was 2+ -The incubation time of the ISM electrode surface was 10 hours.

7. The method for preparing an antifouling lead ion selective electrode using a dendrimer polypeptide according to claim 1, wherein: The antifouling of the antifouling lead ion selective electrode refers to antifouling by bacteria.

8. An antifouling lead ion selective electrode prepared using a dendrimer polypeptide, characterized in that: The antifouling lead ion selective electrode is prepared by the preparation method according to any one of claims 1 to 7.

9. A dendrimer polypeptide for inhibiting bacterial contamination, characterized in that: The structure of the dendrimer polypeptide is shown in formula (I): Formula (I).

10. A dendrimer polypeptide for inhibiting bacterial contamination according to claim 9, characterized in that: The bacteria are Escherichia coli and Staphylococcus aureus.

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