Biofuel cell operating on activated THP-1 cells: A fuel and substrate study

Area of Science:

• Biomedical Engineering
• Electrochemistry
• Cellular Bioenergetics

Background:

• Mammalian cells, particularly white blood cells (WBC), can be utilized for electrochemical energy harvesting.
• Previous research has explored leukocyte biofuel cells, but improvements in power output are needed.

Purpose of the Study:

• To investigate an improved biofuel cell design utilizing phorbol myristate acetate (PMA) activated THP-1 human monocytic cells.
• To identify optimal substrates for THP-1 cell activation and energy generation.
• To quantify the power density achievable with this enhanced biofuel cell system.

Main Methods:

• THP-1 cells were activated using PMA.
• Electrochemical investigations were performed to identify the primary current source.
• Superoxide anion production was measured via WST-1 reduction spectrophotometry (450nm) to assess cellular activity on various substrates (ITO, gold, platinum, glass).
• Substrates were integrated into a two-compartment biofuel cell to measure power density.

Main Results:

• Hydrogen peroxide, originating from NADPH oxidase activity, was confirmed as the primary current source.
• Indium tin oxide (ITO) demonstrated the highest cellular activity and power output compared to other tested substrates and control plates.
• A peak power density of 4.5μW/cm² was achieved, representing a threefold increase over previously reported leukocyte biofuel cells.

Conclusions:

• ITO is a highly effective substrate for enhancing cellular activity and power generation in leukocyte-based biofuel cells.
• The optimized biofuel cell design shows significant potential for improved energy harvesting from mammalian cells.
• This advancement contributes to the development of more efficient bio-electrochemical systems for energy production.