Versatile Method for Producing 2D and 3D Conductive Biomaterial Composites Using Sequential Chemical and Electrochemical Polymerization

Abstract

Flexible and conductive biocompatible materials are attractive candidates for a wide range of biomedical applications including implantable electrodes, tissue engineering, and controlled drug delivery. Here, we demonstrate that chemical and electrochemical polymerization techniques can be combined to create highly versatile silk-conducting polymer (silk-CP) composites with enhanced conductivity and electrochemical stability. Interpenetrating silk-CP composites were first generated via in situ deposition of polypyrrole during chemical polymerization of pyrrole. These composites were sufficiently conductive to serve as working electrodes for electropolymerization, which allowed an additional layer of CP to be deposited on the surface. This sequential method was applied to both 2D films and 3D sponge-like silk scaffolds, producing conductive materials with biomimetic architectures. Overall, this two-step technique expanded the range of available polymers and dopants suitable for the synthesis of mechanically robust, biocompatible, and highly conductive silk-based materials.

Performance of silk‐polypyrrole bilayer actuators under biologically relevant conditions

“…Silk‐PPy composite films were synthesized as previously described . Briefly, aqueous silk solution regenerated from B. Mori cocoons was cast onto a silicone baking mat and allowed to dry for 24 h, resulting in sheets with an approximate thickness of 0.07–0.1 mm.…”

“…The cell was filled with an aqueous solution containing 0.1 M of pyrrole and 0.25 M sodium dodecylbenzenesulfonate (NaDBS) anion as the dopant. To achieve optimal sheet resistivity a total charge of 2 C cm −2 was passed for each film electropolymerization. Cross‐sectional SEM images of samples prepared as described here can be found in Ref.…”

“…Previously, our group developed strategies for incorporating conductive PPy into silk structures to form a completely integrated interpenetrating network (IPN) of silk and PPy, and demonstrated their use as electromechanical bilayer bending actuators . These silk‐PPy bilayer actuators were capable of generating stresses comparable to human muscle (>0.1 MPa) and were electrochemically stable .…”

Recent Advances in Nanostructured Conducting Polymers: from Synthesis to Practical Applications

“…[ [9][10][11][12][13][14] Electrochemical polymerization An oxidizing agent is not required for this route, which is an efficient approach for depositing CPs on substrates. Some monomers are theoretically not electropolymerizable.…”

“…For the electrochemical approach, investigations of the deposition potential and temperature [96] and chloroform as the environment [97] have been undertaken. Finally, a new anionic dopant, sulfanilic acid azochromotrop [18], was investigated for a combination of chemical and electrochemical polymerization [13,14]. Based on the electrochemical route, the electrophoretic force was successfully exploited for the deposition and assembly of CP nanomaterials.…”