Phytochemical-Mediated Green Synthesis of Ag Nanowires and Fabrication of Highly Flexible, Biocompatible, and Antibiofouling Conductive Films

This study describes a green, low-energy, and cost-effective route by which Ag nanowires (AgNWs) with diameters of 60–70 nm and lengths of 21–22 μm can be synthesized at room temperature using naturally occurring phytochemicals (gallic acid and glucose) as the reducing and capping/shape-directing agents. The AgNWs were found to self-assemble from Ag nanoparticles and nanorods into 1D arrangements via an oriented attachment mechanism. Toxicological assessments revealed that longer nanowires are less toxic, in terms of acute oral toxicity and basal dermal cytotoxicity. The AgNWs were further incorporated in a mixed cellulose ester (MCE) substrate to fabricate highly flexible conducting films, exhibiting controllable light transmission, tunable hydrophilicity/hydrophobicity, excellent bending stability, and antibiofouling properties. Additionally, linear micropatterns can be created on the AgNW-MCE composite films by conventional photolithography and wet chemical etching. The patterned films can be connected to an electric circuit to light up an LED bulb, and the conducting stability remains at different application scenarios (human wrist with different angles, bovine serum, and bacterial suspensions), illustrating immense potential as skin-attachable or implantable bioelectronics. This work has paved the way toward the scalable phytosynthesis of AgNWs with tailored properties for technical applications in wearable and flexible electronics.