An Anisotropic and Stable‐Conductance Patch for Mechanical–Electrical Coupling With Infarcted Myocardium

Figures

• 

  FIGURE 1. Biomimetic design of anisotropic patches for cardiac repair. (a) Schematic and (b) fluorescence micrographs of the multilevel structure of native cardiac tissue. (c) Schematic of HACMP production; (d) Schematic of mechanical–electrical coupling of HACMP to infarcted myocardium. (e) Optical picture and (f,g) SEM images of HACMP‐0.5. (h) Stress–strain curve and (i) Young's modulus of the patches. (j) Tensile cycling experiment of HACMP‐0.5 at 20% strain.

• 

  FIGURE 2. Stable conduction of hierarchical conductive myocardial patches in dynamic environments. (a) Schematic diagram illustrating the structural variations of the bionic striated PPy coating during cardiac systole and diastole. (b) Relative resistance changes under stretching of the conductive myocardial patch. (c) Cyclic endurance profile of the conductive myocardial patch at 20% strain. (d) Schematic illustration and (e) optical image of HACMP‐0.5, which is connected to a circuit containing an LED and glued on the surface of an isolated porcine heart. Schematic diagram of the (f) simulator and (g) system for the myocardial mechanical–electrical coupling microenvironment. (h) Performance of HACMP‐0.5 in conducting electrical signals with and without strain. (i) Performance of HACMP‐0.5 in stabilizing conductance electrical signals under 20% strain at 1 Hz.

• 

  FIGURE 3. Mechanical–electrical coupling of tunable anisotropic conductive myocardial patches with the infarcted myocardium. (a) Schematic representation of the patch anisotropy aligned with the myocardium anisotropy. (b) Schematic diagram of the methodology for electromyographic testing of anisotropy patches. (c) Received electrical signals and (d) their associated intensity. (e) Schematic illustration of local strain measurement on infarcted myocardium pre‐ and post‐patch application. (f) Local strains in longitudinal and circumferential directions upon stretching the myocardium. Dashed circles: infarction. (g) Young's modulus and (h) anisotropy ratio of HACMP‐0.5 at a fixed warp density and variable weft densities. (i) Conductivity and (j) anisotropy ratio of HACMP‐0.5 at a fixed warp density and variable weft densities. (k) Young's modulus and (l) anisotropy ratio of HACMP‐0.5 with the same weft density and different warp densities. (m) Conductivity and (n) anisotropy ratio of HACMP‐0.5 with the same weft density and different warp densities. The purple band represents the range of the anisotropy ratio of the natural myocardial tissue. ***p < 0.001; **p < 0.01; and *p < 0.05.

• 

  FIGURE 4. Therapeutic effect of anisotropic patch implantation on cardiac function recovery. (a) Schematic diagram of infarction resulting from myocardial ischemia. (b) Infarcted zone of the left ventricle following coronary artery ligation. (c) Image showing the myocardial patch implanted in the infarcted region. (d) Image of HACMP‐0.5 prior to implantation. (e) Echocardiography images of different groups. (f) Changes in LVIDd, LVIDs, FS, and EF in each group determined by echocardiography. Statistical analysis for (g) FS and (h) EF. (i) Masson's trichrome staining in different groups. Blue, fibrosis tissue; red, myocardium. Statistical analysis for (j) infarct wall thickness and (k) infarct area. n = 4; ***p < 0.001; **p < 0.01; and *p < 0.05).

• 

  FIGURE 5. Electrocardiography (ECG) and electrophysiology after implantation of anisotropic patches. (a) Photographs of rats undergoing ECG tests. (b) ECG plots of different groups. (c) Changes in QRS interval as measured by ECG. (d) QRS interval duration. (e) Immunofluorescent staining of α‐actinin (red) and CX‐43 (green) proteins in the infarct area. (f) Immunofluorescent staining of cTnT (red) proteins in the infarct area. Percentage of (g) α‐actinin and (h) CX‐43 proteins calculated from immunofluorescent staining images. n = 4; ***p < 0.001; **p < 0.01; and *p < 0.05.

• 

  FIGURE 6. Anisotropic patches in host heart trigger low inflammation and boost revascularization. (a) Immunofluorescent staining of α‐SMA (red) and CD31 (green) proteins in the infarct area. Percentage of (b) α‐SMA and (c) CD31 proteins calculated from immunofluorescent staining images. (d) Immunofluorescent staining of CD86 (red) and CD163 (green) proteins in the infarct area. (e) Total M1 and M2 type macrophages and (f) M2/M1 type macrophage ratio calculated from immunofluorescent staining images. n = 4; ***p < 0.001; **p < 0.01; and *p < 0.05.