skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Monitoring the effects of chemical stimuli on live cells with metasurface-enhanced infrared reflection spectroscopy
Infrared spectroscopy has found wide applications in the analysis of biological materials. A more recent development is the use of engineered nanostructures – plasmonic metasurfaces – as substrates for metasurface-enhanced infrared reflection spectroscopy (MEIRS). Here, we demonstrate that strong field enhancement from plasmonic metasurfaces enables the use of MEIRS as a highly informative analytic technique for real-time monitoring of cells. By exposing live cells cultured on a plasmonic metasurface to chemical compounds, we show that MEIRS can be used as a label-free phenotypic assay for detecting multiple cellular responses to external stimuli: changes in cell morphology, adhesion, and lipid composition of the cellular membrane, as well as intracellular signaling. Using a focal plane array detection system, we show that MEIRS also enables spectro-chemical imaging at the single-cell level. The described metasurface-based all-optical sensor opens the way to a scalable, high-throughput spectroscopic assay for live cells.  more » « less
Award ID(s):
1719875
PAR ID:
10325582
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Lab on a Chip
Volume:
21
Issue:
20
ISSN:
1473-0197
Page Range / eLocation ID:
3991 to 4004
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, SPIE BiOS, 2020 San Francisco, California, United States)
    Surface-enhanced infrared absorption (SEIRA) based on top-down fabricated nanostructures such as nanoantennas and metasurfaces has attracted much attention in recent years. These plasmonic resonant nanostructures can enhance the IR absorption signal of nearby molecules through its nearfield enhancement and have been shown to be able to detect adsorbed monolayers of proteins and lipids through their IR absorption spectra. Here, we demonstrate the continuous monitoring of cellular responses to stimuli using metasurface-enhanced infrared spectroscopy (MEIRS). A431 cells are seeded on a gold plasmonic metasurface fabricated on CaF2 substrate. Continuous monitoring is made possible by integrating the metasurface with a flow chamber, and the IR absorption spectra of the attached cells are measured in reflectance mode under continuous perfusion of cell culture medium. Scanning electron microscopy (SEM) revealed that the cells preferentially adhere to gold surfaces rather than CaF2 surfaces, suggesting that the IR signal measured through MEIRS is highly sensitive to the cells’ attachment and interaction with the gold metasurface. We have monitored the effect of methyl-beta-cyclodextrin, a cholesterol-depleting compound, on A431 cells. Principal component analysis highlighted the complex and subtle spectral changes of the cells. Keywords: MIR spectroscopy, surface-enhanced infrared absorption, metasurface, metasurface enhanced infrared absorption, MEIRS, cell adhesion, methyl-beta-cyclodextrin, cholesterol 
    more » « less
  2. ; ; ; ; ; (, SPIE OPTO)
    Digonnet, Michel J.; Jiang, Shibin (Ed.)
    Plasmonic metasurfaces composed of arrays of rectangular metallic bars are well known for their strong optical response in the infrared spectral range. In this study, we explore the polarization sensitivity of plasmonic metasurfaces for encoding information. The polarization-sensitive optical response depends strongly on the orientation of the metallic bars allowing the encoding of information into the metasurface. Here we demonstrate that a 2-dimensional polarization encoded metasurface can be obtained by using mask-less two-photon polymerization techniques. This novel approach for the fabrication of plasmonic metasurfaces enables the rapid prototyping and adaptation of polarization sensitive metasurfaces for the encoding of multiplexed images. 
    more » « less
  3. ; ; ; ; (, Cells)
    Infrared spectroscopy has drawn considerable interest in biological applications, but the measurement of live cells is impeded by the attenuation of infrared light in water. Metasurface-enhanced infrared reflection spectroscopy (MEIRS) had been shown to mitigate the problem, enhance the cellular infrared signal through surface-enhanced infrared absorption, and encode the cellular vibrational signatures in the reflectance spectrum at the same time. In this study, we used MEIRS to study the dynamic response of live cancer cells to a newly developed chemotherapeutic metal complex with distinct modes of action (MoAs): tricarbonyl rhenium isonitrile polypyridyl (TRIP). MEIRS measurements demonstrated that administering TRIP resulted in long-term (several hours) reduction in protein, lipid, and overall refractive index signals, and in short-term (tens of minutes) increase in these signals, consistent with the induction of endoplasmic reticulum stress. The unique tricarbonyl IR signature of TRIP in the bioorthogonal spectral window was monitored in real time, and was used as an infrared tag to detect the precise drug delivery time that was shown to be closely correlated with the onset of the phenotypic response. These results demonstrate that MEIRS is an effective label-free real-time cellular assay capable of detecting and interpreting the early phenotypic responses of cells to IR-tagged chemotherapeutics. 
    more » « less
  4. ; ; ; ; ; ; ; ; (, Applied Physics Letters)
    Metasurfaces consisting of an array of planar sub-wavelength structures have shown great potentials in controlling thermal infrared radiation, including intensity, coherence, and polarization. These capabilities together with the two-dimensional nature make thermal metasurfaces an ultracompact multifunctional platform for infrared light manipulation. Integrating the functionalities, such as amplitude, phase (spectrum and directionality), and polarization, on a single metasurface offers fascinating device responses. However, it remains a significant challenge to concurrently optimize the optical, electrical, and thermal responses of a thermal metasurface in a small footprint. In this work, we develop a center-contacted electrode line design for a thermal infrared metasurface based on a gold nanorod array, which allows local Joule heating to electrically excite the emission without undermining the localized surface plasmonic resonance. The narrowband emission of thermal metasurfaces and their robustness against temperature nonuniformity demonstrated in this work have important implications for the applications in infrared imaging, sensing, and energy harvesting. 
    more » « less
  5. ; ; ; ; (, Optics Express)
    Integrating phase-change materials in metasurfaces has emerged as a powerful strategy to realize optical devices with tunable electromagnetic responses. Here, phase-change chiral metasurfaces based on GST-225 material with the designed trapezoid-shaped resonators are demonstrated to achieve tunable circular dichroism (CD) responses in the infrared regime. The asymmetric trapezoid-shaped resonators are designed to support two chiral plasmonic resonances with opposite CD responses for realizing switchable CD between negative and positive values using the GST phase change from amorphous to crystalline. The electromagnetic field distributions of the chiral plasmonic resonant modes are analyzed to understand the chiroptical responses of the metasurface. Furthermore, the variations in the absorption spectrum and CD value for the metasurface as a function of the baking time during the GST phase transition are analyzed to reveal the underlying thermal tuning process of the metasurface. The demonstrated phase-change metasurfaces with tunable CD responses hold significant promise in enabling many applications in the infrared regime such as chiral sensing, encrypted communication, and thermal imaging. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email