Abstract:Brillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the in… Show more
“…This permits localisation of the PEM-tip to a non-contact z -offset position for 2D point scanning (e.g., z ≈ 2 μm). Figure 2 c–f show the capability to generate high resolution 3D images from single 2D point scans, revealing cellular morphology and 3D-resolved Brillouin frequency shifts that are consistent with previous microscopy measurements on fibroblasts 21 . Fig.…”
Section: Resultssupporting
confidence: 86%
“…1 c–e), i.e., f B (Δ v ( z )). Due to the p s temporal sampling rate of the PEM system (see Methods), we are capable of resolving longitudinal changes in viscoelasticity on the order of the phonon wavelength ( λ p h o n o n ~ 300 nm) through time-frequency analysis (TFA) of the ToF signal 20 , 21 (Fig. 1 e).…”
This report presents an optical fibre-based endo-microscopic imaging tool that simultaneously measures the topographic profile and 3D viscoelastic properties of biological specimens through the phenomenon of time-resolved Brillouin scattering. This uses the intrinsic viscoelasticity of the specimen as a contrast mechanism without fluorescent tags or photoacoustic contrast mechanisms. We demonstrate 2 μm lateral resolution and 320 nm axial resolution for the 3D imaging of biological cells and Caenorhabditis elegans larvae. This has enabled the first ever 3D stiffness imaging and characterisation of the C. elegans larva cuticle in-situ. A label-free, subcellular resolution, and endoscopic compatible technique that reveals structural biologically-relevant material properties of tissue could pave the way toward in-vivo elasticity-based diagnostics down to the single cell level.
“…This permits localisation of the PEM-tip to a non-contact z -offset position for 2D point scanning (e.g., z ≈ 2 μm). Figure 2 c–f show the capability to generate high resolution 3D images from single 2D point scans, revealing cellular morphology and 3D-resolved Brillouin frequency shifts that are consistent with previous microscopy measurements on fibroblasts 21 . Fig.…”
Section: Resultssupporting
confidence: 86%
“…1 c–e), i.e., f B (Δ v ( z )). Due to the p s temporal sampling rate of the PEM system (see Methods), we are capable of resolving longitudinal changes in viscoelasticity on the order of the phonon wavelength ( λ p h o n o n ~ 300 nm) through time-frequency analysis (TFA) of the ToF signal 20 , 21 (Fig. 1 e).…”
This report presents an optical fibre-based endo-microscopic imaging tool that simultaneously measures the topographic profile and 3D viscoelastic properties of biological specimens through the phenomenon of time-resolved Brillouin scattering. This uses the intrinsic viscoelasticity of the specimen as a contrast mechanism without fluorescent tags or photoacoustic contrast mechanisms. We demonstrate 2 μm lateral resolution and 320 nm axial resolution for the 3D imaging of biological cells and Caenorhabditis elegans larvae. This has enabled the first ever 3D stiffness imaging and characterisation of the C. elegans larva cuticle in-situ. A label-free, subcellular resolution, and endoscopic compatible technique that reveals structural biologically-relevant material properties of tissue could pave the way toward in-vivo elasticity-based diagnostics down to the single cell level.
“…In our analysis, the transfer of coherent phonons from the first mode to the second may be thought of as outcoupling of the lasing phonons, by time-modulating the Q-factor of the first, lasing, mode. Our studies of pulsed lasing can have potential applications in levitated phonon transport [26,52], acoustic imaging [53,54], sensing [55] and information processing technologies [56,57].…”
We theoretically investigate the active Q-switching of an optical tweezer phonon laser [R. M. Pettit et al., Nature Photonics 13, 402 (2019)] operating in a coupled-mode configuration. One of the modes is lasing and outcouples to the second mode. The coupling is induced via asymmetric modulation of the trap potential in the transverse plane of the trapped nanoparticle. We show that a time-modulated coherent coupling between two transverse modes of oscillation of an optically levitated nanoparticle holds the key to coherent pulsed phonon transfer between them. Our analytical and numerical results on the position dynamics, phonon dynamics as well as second order coherence confirms pulsed phonon lasing transfer between the transverse modes. Our work on Q-switched operation of the optical tweezer phonon laser enhances understanding of the analogies between optical and mechanical lasers, and is relevant to levitated phonon transport, acoustic imaging, sensing and information processing technologies.
“…The in-depth resolution is then limited by the acoustic wavelength , with n the refractive index for cell, see Section 3.2 . This depth profiling of the signal amplitude at the Brillouin frequency-shift was achieved with bovine endothelial, mouse adipose [124] and mouse 3T3 [125] fixed cells in buffer solution. Fig.…”
Section: Applications To the Nanoscale Investigation Of Cell Mechanicsmentioning
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
