Ultra high‐speed sorting

Abstract

BackgroundCell sorting has a history dating back approximately 40 years. The main limitation has been that, although flow cytometry is a science, cell sorting has been an art during most of this time. Recent advances in assisting technologies have helped to decrease the amount of expertise necessary to perform sorting.MethodsDroplet‐based sorting is based on a controlled disturbance of a jet stream dependent on surface tension. Sorting yield and purity are highly dependent on stable jet break‐off position. System pressures and orifice diameters dictate the number of droplets per second, which is the sort rate limiting step because modern electronics can more than handle the higher cell signal processing rates.ResultsCell sorting still requires considerable expertise. Complex multicolor sorting also requires new and more sophisticated sort decisions, especially when cell subpopulations are rare and need to be extracted from background. High‐speed sorting continues to pose major problems in terms of biosafety due to the aerosols generated.ConclusionsCell sorting has become more stable and predictable and requires less expertise to operate. However, the problems of aerosol containment continue to make droplet‐based cell sorting problematical. Fluid physics and cell viability restraints pose practical limits for high‐speed sorting that have almost been reached. Over the next 5 years there may be advances in fluidic switching sorting in lab‐on‐a‐chip microfluidic systems that could not only solve the aerosol and viability problems but also make ultra high‐speed sorting possible and practical through massively parallel and exponential staging microfluidic architectures. © 2005 International Society for Analytical Cytology

Bacterial Display Peptides for Use in Biosensing Applications

“…For example, high throughput screening is desired to handle large libraries (several mL of > 10 10 member libraries) in a reasonable time frame (several minutes). Typically with the currently employed sorting technologies relying on a combination of MACS and FACS sorting, the throughput is determined by the MACS sample pre-enrichment prior to FACS sorting since fluorescence cell sorting methods using ultra high-speed sorting only approach 100,000 cells/sec (Leary, 2005). The recovery (fraction of binders collected relative to the total number of binders in the naïve library) is www.intechopen.com Bacterial Display Peptides for Use in Biosensing Applications 631 also critical to affinity ligand development and to applications in medicine for cell identification, such as cancer cell isolation and population enrichment (Lara et al, 2004;Xu et al, 2009;& Krivacic et al, 2004).…”

On-Chip Fluorescence-Activated Cell Sorting by an Integrated Miniaturized Ultrasonic Transducer

“…malaria parasites, or studies of cellular responses upon inserted mutations or various stimuli are other possible applications. 1 The gentleness of the acoustic switch makes it especially useful in applications for mammalian cells where viability in the following step is required, such as for transplantation. Also, beads can be functionalized to bind and extract smaller cells or analytes of interest from a larger mixture and the beads could be sorted from the solution for further analysis.…”

“…Sample purity and the ability to handle infectious material in closed systems and integration with other steps are key motivations in addition to the ability to handle small sample volumes, the potentially lower cost and a lower requirement of trained operating personnel. The large-scale fluorescence-activated cell sorters, FACS, offer extreme cell throughputs (5 000 to 40 000 cells s -1 ) 1 and multi-parameter differentiation. However, cell sorters on-chip may not necessarily have to reach the same speed and the aforementioned benefits may be important enough to favor an on-chip alternative.…”

“…only unwanted droplets are deflected while the desired droplets move straight ahead. 1 A sorting method that has achieved much attention recently is optical sorting, but the high light intensity levels employed are related to viability issues since not only temperature increase but also photodamage 'optocution' 16 are direct effects of the light. Optical sorting, weather the optical system is located off-or on-chip requires beam shaping objects 17,18 and an extra optical beam branch besides the one for fluorescence detection.…”

3D Pulsed Laser Triggered High Speed Microfluidic Fluorescence Activated Cell Sorter

“…A sorter utilizing a piezoelectric actuator with a PDMS valve provided an enrichment of ~230-fold and after-sort purity of ~65% at 1,000 cells sec −1 [17]. Overall, the major challenge of μFACS systems to date is the low sorting throughput and purity, compared to conventional aerosol-based FACS that yield >90% purity at 70,000 cells sec −1 [18][19][20]. In some fields such as oncology, stem cell research, or infectious disease biology, high purity sorting for rare target cells at high-throughput is essential.…”