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Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics

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Abstract

Electronics that are capable of intimate, non-invasive integration with the soft, curvilinear surfaces of biological tissues offer important opportunities for diagnosing and treating disease and for improving brain/machine interfaces. This article describes a material strategy for a type of bio-interfaced system that relies on ultrathin electronics supported by bioresorbable substrates of silk fibroin. Mounting such devices on tissue and then allowing the silk to dissolve and resorb initiates a spontaneous, conformal wrapping process driven by capillary forces at the biotic/abiotic interface. Specialized mesh designs and ultrathin forms for the electronics ensure minimal stresses on the tissue and highly conformal coverage, even for complex curvilinear surfaces, as confirmed by experimental and theoretical studies. In vivo, neural mapping experiments on feline animal models illustrate one mode of use for this class of technology. These concepts provide new capabilities for implantable and surgical devices.

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Figure 1: Schematic illustration and images corresponding to steps for fabricating conformal silk-supported PI electrode arrays.
Figure 2: Time-dependent changes as the silk substrate dissolves.
Figure 3: Neural electrode arrays of varying thickness on simulated brain models to illustrate flexibility.
Figure 4: Mechanical modelling, theoretical predictions and measured properties.
Figure 5: Photographs and data from animal validation experiments.

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  • 23 April 2010

    In the original published versions of this Article the author list was incorrect. This has now been corrected in both the full-text HTML and the PDF versions.

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Acknowledgements

We thank T. Banks and J. A. N. T. Soares for help using facilities at the Frederick Seitz Materials Research Laboratory. This material is based on work supported by a National Security Science and Engineering Faculty Fellowship and the US Department of Energy, Division of Materials Sciences under Award No. DEFG02-91ER45439, through the Frederick Seitz MRL and Center for Microanalysis of Materials at the University of Illinois at Urbana-Champaign. The aspects of the work relating to silk are supported by the US Army Research Laboratory and the US Army Research Office under contract number W911 NF-07-1-0618 and by the DARPA-DSO and the NIH P41 Tissue Engineering Resource Center (P41 EB002520). Work at the University of Pennsylvania is supported by the National Institutes of Health Grants (NINDS RO1-NS041811-04, R01 NS 48598-04), and the Klingenstein Foundation. J.A.R. is supported by a National Science Security and Engineering Faculty Fellowship.

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D-H.K., J.V., J.J.A., J.X., L.V., Y-S.K., D.C., D.L.K., F.G.O., Y.H, K-C.H., M.R.Z., B.L. and J.A.R. designed the experiments. D.H.K., E.S.F., J.V., J.J.A., J.X., L.V., Y-S.K., B.P. and J.A.B. carried out experiments and analysis. D-H.K., J.V., J.J.A., J.X., L.V., J.A.B., D.C., D.L.K., F.G.O., Y.H., B.L. and J.A.R. wrote the paper.

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Correspondence to Brian Litt or John A. Rogers.

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Kim, DH., Viventi, J., Amsden, J. et al. Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics. Nature Mater 9, 511–517 (2010). https://doi.org/10.1038/nmat2745

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