Laser particles with omnidirectional emission for cell tracking

Abstract

The ability to track individual cells in space over time is crucial to analyzing heterogeneous cell populations. Recently, microlaser particles have emerged as unique optical probes for massively multiplexed single-cell tagging. However, the microlaser far-field emission is inherently direction-dependent, which causes strong intensity fluctuations when the orientation of the particle varies randomly inside cells. Here, we demonstrate a general solution based on the incorporation of nanoscale light scatterers into microlasers. Two schemes are developed by introducing either boundary defects or a scattering layer into microdisk lasers. The resulting laser output is omnidirectional, with the minimum-to-maximum ratio of the angle-dependent intensity improving from 0.007 (−24 dB) to > 0.23 (−6 dB). After transfer into live cells in vitro, the omnidirectional laser particles within moving cells could be tracked continuously with high signal-to-noise ratios for 2 h, while conventional microlasers exhibited frequent signal loss causing tracking failure.

Biophotonic probes for bio-detection and imaging

“…To solve this problem, Tang et al modified microdisk lasers with rough surface, boundary defects or scattering layers to generate light scattering for omnidirectional emission (Fig. 5bI ) 103 . These modified omnidirectional microlasers achieved continuous tracking of moving cells for 2 h, which was difficult to achieve for traditional direction-dependent microlasers owing to the frequent signal loss (Fig.…”

“…Copyright 2019, Springer Nature. b Microdisk lasers with omnidirectional emission for long-time cell tracking 103 . I: SEM images of conventional microdisk lasers (CLPs) and modified microdisk lasers.…”

Sensitivity Dependence of Single Nanoparticle Mass Detection Using Mechanical Oscillations in Optical Microcavities

“…Note that the sensitivity is also dependent on the microcavity material, because the mechanical frequency and the effective mass are dependent on the rigidity and density of the material. For microtoroidal cavity fabricated using different materials or cavity with different shapes (e.g., microbubble [31], [32] and microdisk [33]), the sensitivity optimization can follow similar process proposed in this work.…”

Fiber Optofluidic Microlasers: Structures, Characteristics, and Applications

“…Optofluidic biolasers have been demonstrated for labeling, tracking, and imaging of cells and tissues, owing to their excellent biocompatibility, spectral multiplexing capability, high contrast ratio and strong background suppression. [ 218,234 ] They utilize biological materials as the gain medium, or as part of the resonator. Different biocompatible materials have been employed to form a biolaser, such as gelatin, [ 235 ] amyloids, [ 171 ] polysaccharides, [ 236 ] starch, [ 237 ] lipids, [ 25 ] DNA, [ 238 ] silk, [ 239 ] liquid crystal, [ 240 ] wood, [ 241 ] and hydrogels.…”