This paper reports an integrated dual-modality microfluidic sensor chip, consisting of a patterned periodic array of nanoposts coated with gold (Au) and graphene oxide (GO), to detect target biomarker molecules in a limited sample volume. The device generates both electrochemical and surface plasmon resonance (SPR) signals from a single sensing area of Au–GO nanoposts. The Au–GO nanoposts are functionalized with specific receptor molecules, serving as a spatially well-defined nanostructured working electrode for electrochemical sensing, as well as a nanostructured plasmonic crystal for SPR-based sensing via the excitation of surface plasmon polaritons. High sensitivity of the electrochemical measurement originates from the presence of the nanoposts on the surface of the working electrode where radial diffusion of redox species occurs. Complementarily, the SPR detection allows convenient tracking of dynamic antigen–antibody interactions, to describe the association and dissociation phases occurring at the sensor surface. The soft-lithographically formed nanoposts provide high reproducibility of the sensor response to epidermal growth factor receptor ( ErbB2 ) molecules even at a femtomolar level. Sensitivities of the electrochemical measurements to ErbB2 are found to be 20.47 μA μM −1 cm −2 in a range from 1 fM to 0.1 μM, and those of the SPR measurements to bemore »
This content will become publicly available on May 16, 2023
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.
- Award ID(s):
- 1932963
- Publication Date:
- NSF-PAR ID:
- 10380119
- Journal Name:
- Materials Chemistry Frontiers
- Volume:
- 6
- Issue:
- 10
- Page Range or eLocation-ID:
- 1253 to 1260
- ISSN:
- 2052-1537
- Sponsoring Org:
- National Science Foundation
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