Research ArticleAPPLIED SCIENCES AND ENGINEERING

Single-molecule detection of biomarker and localized cellular photothermal therapy using an optical microfiber with nanointerface

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Science Advances  20 Dec 2019:
Vol. 5, no. 12, eaax4659
DOI: 10.1126/sciadv.aax4659
  • Fig. 1 Preparation of the microfiber sensor.

    (A) Scheme of the functionalization of the microfiber biosensor. (B) X-ray photoelectron spectroscopy (XPS) spectrum of the BP spacer. (C) Raman spectrum of the microfiber with a BP spacer. (D and E) The atomic force microscopy (AFM) images of the microfiber surface with BP spacer [consisting of poly(methyl methacrylate) (PMMA) double layer]. (F) Extinction spectrum of the Au nanohybrids. (G and H) The AFM images of the microfiber surface with BP-supported Au nanohybrid nanointerface. (I) Schematic of the stepwise shift in the transmission spectrum induced by single-molecule ErbB2 binding. (J) Schematic of the wavelength shift in the transmission spectrum induced by MCF-7 cell binding. (K) Scheme of the optical setup. a.u., aribtrary units.

  • Fig. 2 ErbB2 sensing results.

    (A to C) Measured transmission spectra of the as-prepared sensor and control microfibers at different concentrations of ErbB2. (D to F) Wavelength shifts of the sensor and control microfibers versus the concentration of ErbB2. (G to I) Optical response of the three sensors to ErbB2 at a concentration of 1 aM. (A, D, and G, the as-prepared sensor; B, E, and H, the microfiber with antibodies on a nanointerface consisting of only Au nanohybrids; C, F, and I, the microfiber with antibodies but without any interface.)

  • Fig. 3 Two-microfiber experiment.

    (A) Optical setup of the binding event confirmation experiment. (B to G) Wavelength shifts recorded by the two microfibers upon injecting various solutions. (B to D, as-prepared microfiber; E to G, control microfiber.)

  • Fig. 4 Specificity of the as-prepared sensor.

    Optical response of the as-prepared sensor to interfering proteins and cells. (A) BSA solution at a concentration of 1 aM. (B) IgG solution at a concentration of 1 aM. (C) L929 cells at a concentration of 1 cell/μl. (D) BRL3A cells at a concentration of 1 cell/μl.

  • Fig. 5 Cell capture and cellular photothermal therapy.

    (A) Wavelength shift of the microfiber in response to MCF-7 cells at a density of 1 cell/μl (with pump off; baseline, cell culture fluid without MCF-7 cells). (B to F) Optical microscopy images of the microfiber surface capturing an MCF-7 cell and killing it through photothermal effect.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/12/eaax4659/DC1

    Fig. S1. Illustration of the fabricated microfiber device.

    Fig. S2. The measured transmission spectrum of silica microfiber.

    Fig. S3. The simulated modal distributions of silica microfiber and microfiber with BP spacer.

    Fig. S4. Optical stabilities of the microfiber sensors in PBS solution.

    Fig. S5. Wavelength shifts recorded by the control microfiber when target molecules were added in its side.

    Fig. S6. Optical response with respect to time by using microfiber functionalized by Au nanohybrids without BP spacer in BSA solution and IgG solution at a concentration of 1 aM.

    Fig. S7. Wavelength shift of the microfiber with BP-supported Au nanohybrid interface under pump laser coupling and the wavelength shift of the microfiber versus temperature increase.

    Fig. S8. The AFM images of the microfiber functionalized with different nanointerfaces.

    Fig. S9. HR-TEM image of Au nanohybrids and near-field intensity of electrical field on different nanointerfaces.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Illustration of the fabricated microfiber device.
    • Fig. S2. The measured transmission spectrum of silica microfiber.
    • Fig. S3. The simulated modal distributions of silica microfiber and microfiber with BP spacer.
    • Fig. S4. Optical stabilities of the microfiber sensors in PBS solution.
    • Fig. S5. Wavelength shifts recorded by the control microfiber when target molecules were added in its side.
    • Fig. S6. Optical response with respect to time by using microfiber functionalized by Au nanohybrids without BP spacer in BSA solution and IgG solution at a concentration of 1 aM.
    • Fig. S7. Wavelength shift of the microfiber with BP-supported Au nanohybrid interface under pump laser coupling and the wavelength shift of the microfiber versus temperature increase.
    • Fig. S8. The AFM images of the microfiber functionalized with different nanointerfaces.
    • Fig. S9. HR-TEM image of Au nanohybrids and near-field intensity of electrical field on different nanointerfaces.

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