On-chip Sort performs cell analysis and cell sorting using a disposable microfluidic chip.

There are two types of microfluidic chips for sorting: 80μm x 80μm size channel chip for cells up to 60μm; and 150μm x 150μm size channel chip for large particles up to 140μm. All fluidics and reservoirs are fabricated on the disposable chip and that makes it possible to be free from contamination between samples nor contamination to the instrument.

The instrument does not have any sheath tanks. This led to the realization of this miniaturized system, and the instrument can be installed inside a standard biosafety cabinet.

The chips are fabricated in a cleanroom for spotless finish, but we also provide sterilized chips to ensure aseptic sorting conditions.

Cells fly through the microchannel by air pressure. Individual cells are analyzed at the laser interrogation point.

The novel sorting method involves gentle but rapid generation of liquid pulses at the sorting junction that pushes only the target cells into the collection reservoir. All the other cells pass through the sorting junction to the waste reservoir.

 

Principle of sorting: Flow shift method (to generate pulse flow)

On-chip's novel sorting method (Flow shift method) eliminates many of the damaging steps involved in "jet-in-air" method used in conventional sorters. This method uses overwhelmingly small pressure. Moreover, our sorting technique does not require generation of droplets, and thus no ultrasonic waves and no electric charges. Fragile and sensitive cells like neurons, iPSCs, etc that can easily be influenced by external stress can be sorted without affecting them at all. The neurons (B) which were sorted using a conventional sorter died due to damage (diagram below). On the other hand, the neurons sorted using On-chip Sort (C) extended its dendrites, just like the control unsorted neurons (A).

The construction of the microfluidic channels achieves narrowing of the sample stream down to 10μm or less by hydrodynamic focusing. Cells are aligned in a line for detection of individual cells using lasers irradiated from the top of the chip. Forward scatter (FSC) and fluorescence are detected through objective lens underneath the chip. Side scattered light (SSC), on the other hand, travels through the chip material and is reflected at the edge (figures below). On-chip Sort can hold a maximum of three lasers from the option of: blue (488nm, primary), violet (405nm), green (561nm), and red (637nm). FSC, SSC and six fluorescence colors can be detected.

The chip is disposable, and thus there is absolutely no need for post-sort washing of the instrument. This also means that users can choose the buffers for sorting. The example includes culture media, sea water, and oil. Sorting of cells does not require any complex calibrations. This makes the instrument very easy to use. All the unsorted cells can be recovered at the waste reservoir, so the sample can be resorted if necessary. Furthermore, the minimal sample volume requirement is 20μL, and thus no wasting of precious samples.