Ultrathin Graphene-Protein Supercapacitors for Miniaturized Bioelectronics

Area of Science:

• Bioelectronics
• Materials Science
• Nanotechnology

Background:

• Implantable bioelectronic devices are typically limited by bulky, toxic batteries.
• Existing batteries pose risks due to toxic materials and potential electrolyte leakage.
• Need for safer, miniaturized, and long-lasting power sources for bioelectronics.

Purpose of the Study:

• To develop implantable protein-based bioelectrochemical capacitors (bECs).
• To create a novel nanocomposite heterostructure using modified proteins and graphene.
• To evaluate the biocompatibility and performance of these new bECs.

Main Methods:

• Fabrication of nanocomposite heterostructures with interlayered reduced graphene oxide and chemically modified mammalian proteins.
• Utilizing biological fluids, such as serum, as electrolytes.
• Assessing cytotoxicity using mouse embryo fibroblasts and COS-7 cell cultures.
• Evaluating device performance, including thickness, flexibility, and energy density.

Main Results:

• Protein-modified graphene nanocomposites demonstrated no toxicity to cell cultures at high concentrations (1600 μg mL⁻¹).
• Unmodified graphene oxide showed significant toxicity even at low doses (10 μg mL⁻¹).
• Fabricated bEC devices are ultra-thin (1 μm), fully flexible, and possess high energy density.
• Encapsulated bECs showed no adverse effects on COS-7 cell cultures during long-term charge/discharge cycles.

Conclusions:

• Developed novel, biocompatible, protein-based bioelectrochemical capacitors (bECs).
• These bECs offer a safe and effective alternative to traditional batteries for implantable devices.
• Potential to enable a new generation of long-life, miniaturized implantable bioelectronic systems.