Spectral reading of optical resonance-encoded cells in microfluidics

Abstract

The ability to label individual cells is useful for single-cell-level studies of complex cellular interactions and heterogeneity. Optically readable cell labeling is attractive as it can be interrogated noninvasively and repeatedly at high speeds. Here we demonstrate the feasibility of large-scale cell barcoding and identification using fluorescent polystyrene microbeads loaded into cells. Intracellular beads with different diameters in a range of 5 to 12 µm produce spectrally distinguished features or barcodes. A microfluidic chip was used to measure fluorescence resonance peaks emitted from individual cells. An algorithm comparing the peak wavelengths to a reference barcode library allowed barcode identification with high accuracy. This work provides guideline to increase the number of unique identifiers and reduce various false-positive, false-negative errors.

Laser particles with omnidirectional emission for cell tracking

“…OLPs allow for continuous and high-speed tracking of single cells, which, combined with the massive spectral multiplexing capability of LPs 7 , enables the study of cellular heterogeneity at the singlecell level in large-scale 3D biological specimens. In addition to cell tracking, the omnidirectionality will facilitate other applications of LPs, such as cellular and biochemical sensing and single-cell analysis in microfluidics 2,8,14,[35][36][37] , by ensuring a high SNR.…”

“…The light scattering in biological tissues does not mitigate this problem because high-resolution spectral readout of LP emission requires confocal detection of essentially non-scattered, or minimally scattered, light. Furthermore, the detection of LPs in instruments with dynamic environments, such as microfluidic channels 14 , would severely suffer from the angular dependence of the emission. Therefore, addressing the directionality of the laser emission would have a high impact on the broad utility of LPs.…”

Optical-resonance-assisted generation of super monodisperse microdroplets and microbeads with nanometer precision

“…Alternatively, size monitoring could be performed by spectroscopy of reflected white light, 36 which can be applied for smaller droplets, even below 1 μm. Recently, multi-cell tagging was demonstrated by the introduction of polymer beads 25 or micrometer sized semiconductor disks 26 into the cell interior. However, cells are uptaking the microlasers randomly and therefore cell tagging is happening indirectly.…”

“…Each bead with slightly different size has a unique emission spectrum, which can be used as a fingerprint to tag samples, products, small particles and even single cells. 19,[25][26][27][28] Most work done till now with WGM barcodes used randomly sized spheres and discs, so that the barcodes were also random. One of the reasons for using random sizes is the difficulty in controlling the size precisely enough to produce an appreciable number of unique barcodes.…”

Dynamic photonic barcodes for molecular detection based on cavity-enhanced energy transfer

“…[1][2][3]11,12,20 Consequently, WGM offers an innovative system of spectroscopic encoding for plenty of applications. [21][22][23][24][25] Recently, micro/nano photonic barcodes have been widely applied in multiplexed bioassays, 24,[26][27][28] cell tagging, 29,30 encoding, 31 anti-counterfeiting, and information security. 21,25,32,33 In general, the concept of optical barcodes usually refers to a fixed spectral pattern corresponding to a single target.…”