Strong Optical Coupling of Lattice Resonances in a Top-down Fabricated Hybrid Metal-Dielectric Al/Si/Ge Metasurface

Optical metasurfaces enable the manipulation of the light-matter interaction in ultrathin layers. Compared with their metal or dielectric counterparts, hybrid metasurfaces resulting from the combination of dielectric and metallic nanostructures can offer increased possibilities for interactions between modes present in the system. Here, we investigate the interaction between lattice resonances in a hybrid metal-dielectric metasurface obtained from a single-step nanofabrication process. Finite-difference time domain simulations show the avoided crossing of the modes appearing in the wavelength-dependent absorptance inside the Ge upon variations in a selected geometry parameter as evidence for strong optical coupling. We find good agreement between the measured and simulated absorptance and reflectance spectra. Our metasurface design can be easily incorporated into a top-down optoelectronic device fabrication process with possible applications ranging from on-chip spectroscopy to sensing.

Isolation of muscle stem cells by fluorescence activated cell sorting cytometry

Satellite cells are a heterogeneous population of muscle progenitors with stem cell properties responsible for the regeneration of adult skeletal muscle. Increasing interest in the therapeutic potential of satellite cells has challenged researchers with the need to purify a homogenous population of muscle progenitors. Here we provide a detailed protocol for the isolation of a pure population of satellite cells using fluorescence activated cell sorting. We give specific guidelines to ameliorate the reproducibility of the satellite cell isolation protocol with the goal to standardize procedures across labs. This protocol identifies satellite cells within adult skeletal muscle as an enriched population of Integrin α7(+)/CD34(+) double positive cells and CD45, CD31, CD11b, and Sca1 negative (Lin(-)) cells (Integrin α7(+)/CD34(+)/Lin(-)). Functional assay shows that Integrin α7(+)/CD34(+)/Lin(-) satellite cells possess high myogenic potential and ability to regenerate muscle depleted satellite cells upon transplantation.