Research ArticleAPPLIED PHYSICS

Light-induced assembly of living bacteria with honeycomb substrate

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Science Advances  28 Feb 2020:
Vol. 6, no. 9, eaaz5757
DOI: 10.1126/sciadv.aaz5757
  • Fig. 1 Bacteria trapped by a honeycomb light–guided substrate.

    (A) Conceptual diagram of the LIA of bacteria with a large area, high density, and high survival rate by laser-induced convection. (B) Schematic diagram of the initial process of LIA. (C) Schematic diagram of convection after bubble generation and trapping of bacteria in the pores on the honeycomb substrate.

  • Fig. 2 Fluorescence image and survival rate of high-density LIA on the honeycomb substrate.

    (A) Stereomicroscopic image of the honeycomb substrate. (B) Fluorescence image (SYTO 9 staining; green) in a mixed state of live and dead bacteria. (C) Fluorescence image of dead bacteria [propidium iodide (PI) staining; red]. (D) Laser power dependence of P. aeruginosa trapping density and survival rate. (E) Laser power dependence of S. aureus capture density and survival rate.

  • Fig. 3 Simulation of the photothermal effect and light-induced convection.

    (A) Calculation model of light-induced bubble formation and convection. (B) Enlarged view of convection in and around the pores on the honeycomb substrate. (C) Velocity distribution of light-induced convection. (D) Temperature distribution due to the photothermal effect.

  • Fig. 4 Current generation by the light-induced accumulation of bacteria.

    (A) Schematic of the experiment of sequential multipoint irradiation. (B) Time dependence of the current generated from the electricity-producing bacteria photoinduced and accumulated by multipoint irradiation (the laser irradiation end was set to 0 min). (C) Laser irradiation point dependency of the change in current value at the end of laser irradiation. Δi: Difference between the initial current density and final current density.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/6/9/eaaz5757/DC1

    Fig. S1. Schematic of experimental setup of LIA of bacteria.

    Fig. S2. Preparation and structural evaluation of honeycomb substrate.

    Fig. S3. Elemental analysis of honeycomb substrate.

    Fig. S4. Behavior of bacteria (P. aeruginosa) trapped in pores of honeycomb substrate during laser irradiation under bright-field condition (transparent optical image).

    Fig. S5. Survival confirmation of bacteria on honeycomb substrate.

    Fig. S6. Fluorescence image of trapped P. aeruginosa by changing laser power (20-s irradiation for each).

    Fig. S7. Fluorescence image of trapped S. aureus by changing laser power (20-s irradiation for each).

    Fig. S8. Comparative experiment of LIA of bacteria with flat gold film [thickness: 10 nm in (27)].

    Fig. S9. Thermographic images of flat Au film and Au-coated honeycomb substrate before and after infrared laser irradiation of 100 mW through 10× dry objective lens (initial power was 200 mW).

    Fig. S10. Thermographic images of flat Au film and Au-coated honeycomb substrate before and after infrared laser irradiation of 35 mW through 10× dry objective lens (initial power was 90 mW).

    Fig. S11. Thermographic images of flat Au film and Au-coated honeycomb substrate before and after infrared laser irradiation of 20 mW through 10× dry objective lens (initial power was 65 mW).

    Fig. S12. Model for the calculation of light-induced convection in honeycomb substrate.

    Fig. S13. Simulation of optical response of a gold thin film on the substrate.

    Movie S1. An example of fluorescence image of LIA process of S. aeruginosa into Au-coated honeycomb substrate (SYTO 9) with a laser power of 40 mW similar to Fig. 2B.

    Movie S2. Transparent image of S. aeruginosa in Au-coated honeycomb substrate after LIA, which corresponds to fig. S4.

  • Supplementary Materials

    The PDF file includes:

    • Fig. S1. Schematic of experimental setup of LIA of bacteria.
    • Fig. S2. Preparation and structural evaluation of honeycomb substrate.
    • Fig. S3. Elemental analysis of honeycomb substrate.
    • Fig. S4. Behavior of bacteria (P. aeruginosa) trapped in pores of honeycomb substrate during laser irradiation under bright-field condition (transparent optical image).
    • Fig. S5. Survival confirmation of bacteria on honeycomb substrate.
    • Fig. S6. Fluorescence image of trapped P. aeruginosa by changing laser power (20-s irradiation for each).
    • Fig. S7. Fluorescence image of trapped S. aureus by changing laser power (20-s irradiation for each).
    • Fig. S8. Comparative experiment of LIA of bacteria with flat gold film thickness: 10 nm in (27).
    • Fig. S9. Thermographic images of flat Au film and Au-coated honeycomb substrate before and after infrared laser irradiation of 100 mW through 10× dry objective lens (initial power was 200 mW).
    • Fig. S10. Thermographic images of flat Au film and Au-coated honeycomb substrate before and after infrared laser irradiation of 35 mW through 10× dry objective lens (initial power was 90 mW).
    • Fig. S11. Thermographic images of flat Au film and Au-coated honeycomb substrate before and after infrared laser irradiation of 20 mW through 10× dry objective lens (initial power was 65 mW).
    • Fig. S12. Model for the calculation of light-induced convection in honeycomb substrate.
    • Fig. S13. Simulation of optical response of a gold thin film on the substrate.
    • Legends for movies S1 and S2

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    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). An example of fluorescence image of LIA process of S. aeruginosa into Au-coated honeycomb substrate (SYTO 9) with a laser power of 40 mW similar to Fig. 2B.
    • Movie S2 (.mp4 format). Transparent image of S. aeruginosa in Au-coated honeycomb substrate after LIA, which corresponds to fig. S4.

    Files in this Data Supplement:

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