Orthogonal redox and optical stimuli can induce independent responses for catechol-chitosan films

Catechol-based materials possess diverse properties that are especially well-suitable for redox-based bioelectronics. Previous top-down, systems-level property measurements have shown that catechol-polysaccharide films (e.g., catechol-chitosan films) are redox-active and allow electrons to flow through the catechol/quinone moieties via thermodynamically-constrained redox reactions. Here, we report that catechol-chitosan films are also photothermally responsive and enable near infrared (NIR) radiation to be transduced into heat. When we simultaneously stimulated catechol-chitosan films with NIR and redox inputs, times-series measurements showed that the responses were reversible and largely independent. Fundamentally, these top-down measurements suggest that the flow of energy through catechol-based materials via the redox-based molecular modality and the electromagnetic-based optical modality can be independent. Practically, this work further illustrates the potential of catecholic materials for bridging bio-device communication because it enables communication through both short-range redox modalities and long-range electromagnetic modalities.