Figure 1
From: Intensity interrogation near cutoff resonance for label-free cellular profiling
Resonant wavelength grating (RWG) sensor for cellular assays.
(a) Illustration of the RWG sensor with a surface coating. The surface mass of cells grown on the surface is detected within the penetration depth. The interrogation of the RWG sensor in a spectral reflection measurement. (b) When compounds are added to the well, two main cellular responses are detected: (1) mass change and (2) dynamic mass redistribution (DMR). (c) Reflection spectrum of the RWG sensor under 26°. Blue and red arrows indicate the resonance at near-cutoff and non-cutoff wavelengths, respectively. The inset shows the appearing resonance mode curve close to the substrate cutoff for the TM1 mode. (d) Cell confluency in an adhesion and spreading assay. (e) Resonance central wavelength, (f) width change and (g) intensity change in percent during the adhesion and spreading assay. (h) The comparison of the central wavelength of the non-cutoff resonance and the intensity of the near-cutoff resonance shows that the intensity of the near-cutoff resonance can be utilized for surface mass detection.
