Blood-built polymers enable light-controlled brain activity
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- Purdue University researchers developed n-PBDF (poly(benzodifurandione)), an n-type conducting polymer synthesized inside living animals using hemoglobin in blood as a natural catalyst, as reported in Science (2026).
- The build process works by injecting benzodifurandione (BDF) monomers into zebrafish embryos and mice, where hemoproteins and oxygen produce ferryl hemoprotein intermediates that link monomers into long polymer chains via radical-mediated reaction.
- Reductive doping with surrounding water and biological ions like sodium (Na⁺) gives the polymer its electrical conductivity, yielding a soft, tissue-like electrode that integrates with neurons without the stiffness of conventional bioelectronics.
- In vivo tests in zebrafish and mice showed stable electrical interfaces with no toxicity, inflammation, or behavioral changes, and the polymer enabled light-triggered neural control with millisecond precision.
- Near-infrared light activation of the n-PBDF networks produced subtle heat and charge changes that paused neuron firing, demonstrated when trained mice lever-pressing for reward had their brain signals optically interrupted to shift behavior on demand.
Why it matters: Unlike most prior in-body polymer work that used difficult-to-reverse p-type materials with toxicity risks, this n-type, blood-catalyzed approach gave millisecond-precision optical neural control in living mice with zero observed inflammation, pointing to a path toward non-invasive brain interfaces for neurodegenerative and other disorders. The shift from surgically implanted rigid electrodes to self-assembling, tissue-matched electronics could remove the long-standing integration-failure problem that degrades conventional bioelectronic devices over time.
