Research ArticleBIOENGINEERING

Harnessing the hygroscopic and biofluorescent behaviors of genetically tractable microbial cells to design biohybrid wearables

+ See all authors and affiliations

Science Advances  19 May 2017:
Vol. 3, no. 5, e1601984
DOI: 10.1126/sciadv.1601984
  • Fig. 1 An illustration showing the reversible transformation induced by the moisture gradient at different scales for a bilayer biohybrid film.

    (A and B) The film bends tangibly at low humidity levels (A) and becomes flat and glows at high humidity levels (B). (C and D) A cross section of the biohybrid film at the microscopic level, where dehydration of the cell layer (dark green and light green) coated on top of an inert thin film (black) enables the bending of the film at low humidity levels (C), whereas the film becomes flat at high humidity levels (D) through rehydration. The box on the top left corner indicates the contraction (C) and expansion (D) of cells under two conditions. (E and F) The change of cell size and cellular fluorescence with humidity levels due to moisture desorption (E) and adsorption (F) at the cellular level. (G and H) An example of the conformational change of intracellular eGFP at the molecular level due to water removal (G) and water binding (H) at different humidity levels.

  • Fig. 2 Characterization of bilayer biohybrid films at different RH levels.

    (A and B) Shape transformation of a biohybrid film (1.2 cm × 0.9 cm) with a bilayer structure. The top layer is composed of E. coli cells (1 μm thick), and the bottom layer is a latex sheet (200 μm thick). It bends at 15% RH (A) and becomes flat at 95% RH (B). (C) The bending curvature of this biohybrid film at different RH levels. (D and E) Topological images of a cell at 15% RH (C) and 95% RH (D) obtained from AFM. (F) The cell volume change at different RH levels scanned by AFM. (G and H) Fluorescence images of a biohybrid film coated with E. coli with eGFP expression. It shows little fluorescence at 15% RH (G) compared with that at 95% RH (H). (I) Fluorescence intensity varies along with the bending curvature of the film when exposed to humid air in a dry environment. RFU, relative fluorescence units. (J) Bending angle for different types of cells. (K) Bending angle for major cellular biological components. (L and M) Simulation (symbol S) and theoretical model (symbol T) are consistent with experimentally measured bending (symbol E) for varying numbers of cell layer (symbol L) thickness (L) or latex substrate thickness (M).

  • Fig. 3 Performance of sandwich-structured biohybrid film for making sweat-responsive wearables.

    (A) Shape transformation of a flat sandwich-structured biohybrid film when exposed to moisture. (B and C) Stress simulation (B) and experimental bending behavior (C) of a ventilating flap at the open stage when exposed to skin with high humidity. (D) Garment design principle considering both the amount of sweat and body temperature gradient during exercise (note S4). (E) Design of a female garment prototype based on heat maps (left, unit size) and sweat maps (right, percentage of opened area) of the back (note S5). (F and G) Images of garment prototype before exercise with flat ventilation flaps (F) and after exercise with curved ventilation flaps (G). (H and I) Temperature (H) or RH (I) profiles of stagnant air layer near volunteer skin when she wears the female garment with either functional flaps (blue) or nonfunctional flaps (orange). (J to L) The image of the shoe under transmitted light (J) and the flap on the sole at low (K) or high humidity (L). (M to O) The image of the shoe under fluorescence light (M) and the flap on the sole at low (N) or high humidity (O).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/5/e1601984/DC1

    note S1. Experimental data processing.

    note S2. Theoretical prediction.

    note S3. Finite-element simulation.

    note S4. Garment design principle.

    note S5. Flap design based on heat map and sweat map.

    fig. S1. Surface properties of natural latex sheets characterized by SEM.

    fig. S2. Bioprinter working principle.

    fig. S3. Customized humidity-controlled chamber.

    fig. S4. Single cell at different RHs imaged by AFM.

    fig. S5. Map of plasmid pET11a-eGFP-lacZ.

    fig. S6. Confocal images of cell lysate containing eGFP.

    fig. S7. Strain and stress of biohybrid film at different RHs.

    fig. S8. Mechanical characterization of a bilayer hybrid film.

    fig. S9. Assembly of a female running suit focused on the back ventilation through heat press.

    fig. S10. Running suit pattern design–based heat and sweat maps.

    fig. S11. Design of the running shoe with multifunctional fluorescent flaps.

    fig. S12. Sample stability test under 100 dry-wet cycles.

    table S1. Sequence of the synthetic gene used in this study.

    movie S1. Biohybrid bilayer film at different RHs.

    movie S2. Single-cell volume change when decreasing RH imaged by dark-field microscopy.

    movie S3. Fluorescence change of biohybrid film at different RHs.

    movie S4. Simulation of bilayer biofilm bending.

    movie S5. Simulation of sandwich-structured biofilm bending.

    movie S6. Flaps opening for garment during exercise.

  • Supplementary Materials

    This PDF file includes:

    • note S1. Experimental data processing.
    • note S2. Theoretical prediction.
    • note S3. Finite-element simulation.
    • note S4. Garment design principle.
    • note S5. Flap design based on heat map and sweat map.
    • fig. S1. Surface properties of natural latex sheets characterized by SEM.
    • fig. S2. Bioprinter working principle.
    • fig. S3. Customized humidity-controlled chamber.
    • fig. S4. Single cell at different RHs imaged by AFM.
    • fig. S5. Map of plasmid pET11a-eGFP-lacZ.
    • fig. S6. Confocal images of cell lysate containing eGFP.
    • fig. S7. Strain and stress of biohybrid film at different RHs.
    • fig. S8. Mechanical characterization of a bilayer hybrid film.
    • fig. S9. Assembly of a female running suit focused on the back ventilation through heat press.
    • fig. S10. Running suit pattern design–based heat and sweat maps.
    • fig. S11. Design of the running shoe with multifunctional fluorescent flaps.
    • fig. S12. Sample stability test under 100 dry-wet cycles.
    • table S1. Sequence of the synthetic gene used in this study.
    • Legends for movies S1 to S6

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.avi format). Biohybrid bilayer film at different RHs.
    • movie S2 (.avi format). Single-cell volume change when decreasing RH imaged by dark-field microscopy.
    • movie S3 (.avi format). Fluorescence change of biohybrid film at different RHs.
    • movie S4 (.avi format). Simulation of bilayer biofilm bending.
    • movie S5 (.avi format). Simulation of sandwich-structured biofilm bending.
    • movie S6 (.avi format). Flaps opening for garment during exercise.

    Files in this Data Supplement: