fig5

Figure 5. Applications of biodegradable conductive polymers in biomedical and biointerfaced electronics. (A) Schematic illustration of an electro-responsive Dex/HDI conductive hydrogel system for precise on-off drug delivery controlled by external electrical stimuli. The graph on the right shows the drug release profile of indomethacin in phosphate buffer (pH 7.4) under 3 V stimulation (3 min every 30 min). Reprinted with permission from Ref.^[99]. Copyright 2019, Elsevier; (B) Strain sensors based on a CNF-PANI/NR-8 elastomer and nickel foam attached to index fingers for monitoring finger bending. The graph on the right shows the current response during finger motion. Reprinted with permission from Ref.^[71]. Copyright 2019, Elsevier; (C) Schematic illustration of a TFT structure used to evaluate neat and nanoconfined p(DPP-PPD) films under mechanical strain. Bottom: Photographs of nanoconfined p(DPP-PPD) films stretched to 100%. Reproduced with permission from Ref.^[102] under the ACS AuthorChoice license; (D) Left: Photograph of a biodegradable pseudo-CMOS circuit based on p(DPP-PPD), fabricated on a ~25 μm-thick PI substrate and placed on a human brain model. The right panel shows the circuit diagrams and corresponding input–output characteristics. Reproduced with permission from Ref.^[31]. Copyright 2017, National Academy of Sciences. Dex: Dextran; HDI: hexamethylene diisocyanate; CNF: cellulose nanofiber; PANI: polyaniline; NR: natural rubber; TFT: thin-film transistor; P(DPP-PPD): poly(diketopyrrolopyrrole–p-phenyldiamine); CMOS: complementary metal-oxide-semiconductor; PI: polyimide; AT: aniline tetramer; SEBS: polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene.