Pedot

Matrix design, fabrication, and characterization was published elsewhere (Figure 1.B) [4 (link)]. Briefly, the aligned nanofibers were fabricated by electrospinning using 15 % (w/v) Polycaprolactone (PCL, from Sigma-Aldrich) solution in ethanol and methylene chloride (15:85 ratio, from Sigma-Aldrich), with a 2.5 mL/min flow rate and 1 kV/cm potential at ambient temperature and humidity. Dopamine hydrochloride (2 mg/ml, average molecular weight 8000 Da, from Sigma-Aldrich) was coated onto the matrices for 24 hours at pH 8.5 (DOPA/PCL) [41 (link)]. The modified DOPA/PCL matrices were washed, dried, and subsequently coated with 30 μL of 10% poly (3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS 1:2.5, from Sigma-Aldrich) in PBS (PEDOT:PSS/DOPA/PCL). The coated matrices were dried for 48 hours under vacuum and sterilized using 70% ethanol and UV for half an hour/side.

(1) Pt-Ir alloy with nanoscale surface textures: Electrochemical deposition of Pt-Ir used a mixed plating bath of ammonium hexachloroplatinate and hexachloroirridate. The details of the plating solution and deposition processes appear elsewhere.^{[22 ]} Immersing bare electrode surfaces in the plating bath followed by application of a controlled electrochemical potential (Gamry Reference 600 in a 3-electrode system) caused chemical reduction of metal ions in solution to metal alloys on the electrode surfaces. The deposition conditions define the morphology and composition of the resulting coatings. (2) PEDOT:PSS coatings: 0.2g of EDOT (Sigma-Aldrich) added to 200 mL deionized water, stirred overnight for complete dissolution, followed by 0.4 g of PSSNa (Sigma-Aldrich) yielded the solution for electro-polymerization. A potentiostat (Gamry Reference 600) controlled the electro-polymerization processes in a 3-electrode configuration. Immersing the selected electrodes on the 3D-MIM into the solution and applying a constant voltage (1.1 V to Ag/AgCl reference electrode) for 10 minutes, formed the desired coating, as evidence by a change in the color of the electrode surface from gold to dark blue/black. For values above a certain level, the thicknesses of the coatings has little effect on the electrochemical impedance.