The potential of autofluorescence for the detection of single living cells for label‐free cell sorting in microfluidic systems

Abstract

A novel method for studying unlabeled living mammalian cells based on their autofluorescence (AF) signal in a prototype microfluidic device is presented. When combined, cellular AF detection and microfluidic devices have the potential to facilitate high-throughput analysis of different cell populations. To demonstrate this, unlabeled cultured cells in microfluidic devices were excited with a 488 nm excitation light and the AF emission (> 505 nm) was detected using a confocal fluorescence microscope (CFM). For example, a simple microfluidic three-port glass microstructure was used together with conventional electroosmotic flow (EOF) to switch the direction of the fluid flow. As a means to test the potential of AF-based cell sorting in this microfluidic device, granulocytes were successfully differentiated from human red blood cells (RBCs) based on differences in AF. This study demonstrated the use of a simple microfabricated device to perform high-throughput live cell detection and differentiation without the need for cell-specific fluorescent labeling dyes and thereby reducing the sample preparation time. Hence, the combined use of microfluidic devices and cell AF may have many applications in single-cell analysis.

Recent advances in miniaturized microfluidic flow cytometry for clinical use

“…Another example of confocal fluorescence detection is provided by a study on gravity focusing and electric switching [35]. In addition, label-free cell sorting and the confocal detection of autofluorescence have been suggested for the identification of single living cells [63]. In vivo flow cytometry was also found to be possible using a two-beam scan, two-channel detection, and two-photon excitation system [64].…”

A high‐discernment microflow cytometer with microweir structure

“…Broadly speaking, this is achieved using either passive or active focusing techniques. The former methods generally use convergent channels to force the individual cells/particles into an orderly procession [16][17][18], while the latter typically sequence the cells/particles using hydrodynamic focusing [19][20][21][22][23][24][25], electrokinetic focusing [26][27][28][29][30], or dieletrophoretic focusing [31][32][33][34] techniques.…”

Biosensing in a microelectrofluidic system using optical whispering-gallery mode spectroscopy

“…Without the need for labels or agents, detection can be done in situ and in real time, taking great advantages in emerging point-of-care detecting applications. Several label-free optical techniques have been developed, such as autofluorescence, 1 confocal Raman spectroscopy, 2 optical resonance, 3 surface plasmon resonance, 4 and intracavity spectroscopy. 5 There is an increasing awareness of micro-opto-fluidic systems (MOFS), which employ hybrid optical and microfluidic technologies in a micro environment to perform novel functionality and in-depth analysis.…”