RAMAN-ASSISTED CELL SORTING PACK
Sort cells based on their biochemical properties simultaneously
Sort mixture of cells without channels blockage
High throughput of cell sorting based on intrinsic Resonance Raman signal
General presentation of Raman assisted cell sorting (RACS)
Raman Assisted Cell Sorting (RACS) combines Raman spectroscopy and microfluidics to enable non-destructive and label-free sorting of cells based on their biochemical properties. Raman spectroscopy is a non-invasive analytical technique that measures the vibrational frequencies of molecules and provides information about their chemical composition. The label-free approach of Raman-assisted cell sorting connects the phenotypic function of cells with their genotypic characteristics.
However, high throughput isolation of functioning cells from a complex community represents a significant problem [1].
Indeed, spontaneous Raman spectra are often weak: Currently, most of the methods that use cells in microfluidic systems use a “trap-and-release” approach, and the trapping mechanism limits throughput.
Meanwhile, the efficiency of the trap is often dependent on cell size, medium conductivity, refractive index, and/or flow rate.
In this pack, we present a trapping-free RACS system with 3D hydrodynamic flow focusing capable of both continuous and automated sorting of individual cells [2].
We provide a setup for a 3D flow-focusing sorting mechanism. This all-in-one solution can be used to selectively divert cells based on their Raman spectra.
Raman assisted cell sorting pack setup
In this setup, three elements in the sorting device contribute to the efficiency of sorting and the purity of the sorted sample:
- detection of a target cell in the detection chamber
- detection of a targeted cell when it passes the optical sensor in the sorting channel network
- switching of a targeted cell into the collection channel via the pressure unit
A typical pack contains:
- OB1 pressure-driven flow controller (Elveflow)
- Flow sensor: MFS (water-based solutions / 5% accuracy) or BFS (calibration free / 0.2% accuracy) (Elveflow)
- A manifold
- Reservoirs
- All necessary accessories: connectors, tubing, filters, etc…
- Elveflow Software and SDK
What you should have from your end:
- 3D printed unit: to contain and manipulate the cells. It consists of a network of channels and valves that allow for precise control over the flow of cells.
- Inverted fluorescence microscope: so the overall 3D-RACS system operates on it.
- Raman Spectrometer: (laser source, a spectrometer, and a detector). The laser source is used to excite the cells, and the spectrometer is used to measure the Raman scattered light
- Laser Alignment System: The laser alignment system is used to ensure that the laser is properly aligned with the microfluidic device.
- Data Acquisition System: The data acquisition system is used to capture and process the Raman spectra of the cells.
- Cell Sample: The cell sample is prepared by suspending cells in a buffer solution, which is then introduced into the microfluidic chip.
As a proof-of-concept demonstration, Raman-activated sorting of mixtures of Chlorella vulgaris and E. coli has demonstrated a purity level of 92.0% at a throughput of 310 cells per min [2].
Our setup provides a versatile tool for function-based flow cytometry and multiple sorting applications.
References
[1] Hulett, H. R., Bonner, W. A., Barrett, J., & Herzenberg, L. A. (1969). Cell sorting: automated separation of mammalian cells as a function of intracellular fluorescence. Science, 166(3906), 747-749.
[2] Lyu, Y., Yuan, X., Glidle, A., Fu, Y., Furusho, H., Yang, T., & Yin, H. (2020). Automated Raman-based cell sorting with 3D microfluidics. Lab on a Chip, 20(22), 4235-4245.
Raman assisted cell sorting applications
The Raman spectrum of cells provides information about its intrinsic biochemical profile which, in turn, can be used to characterize its phenotype, metabolic activity, and function.
Raman-activated cell sorting (RACS) has several applications in various fields, including biology, medicine, and biotechnology. Some of the key applications of RACS are:
- Cell sorting: RACS can be used to sort cells based on their chemical composition without the need for labeling. This makes it helpful in sorting rare cells, such as circulating tumor cells, stem cells, and immune cells.
- Diagnosis of diseases: RACS can be used to diagnose diseases by analyzing the Raman spectra of cells or tissues (sorting cells based on their drug response). For example, it has been used to diagnose cancer and other diseases by analyzing the Raman spectra of blood or tissue samples.
- Immunophenotyping
- DNA cell cycle/ tumor ploidy
- Gene expression
- DNA degradation
- Enzyme activity
- Drug discovery: RACS can be used to identify new drug targets and evaluate the efficacy of drugs by analyzing the Raman spectra of cells treated with different compounds.
- Study of cell biology: RACS can be used to study the chemical composition of cells and how it changes in response to various stimuli. This can help to understand the mechanisms of cell signaling, metabolism, and other cellular processes:
- Ion flux
- Cell viability
- Intracellular protein staining
- pH changes
- Cell tracking and proliferation
- DNA synthesis
- Chromatin structure
- Total protein
- Membrane fusion/ run-over
- Oxidative metabolism
- Membrane potential
- Sorting, Redox state
- Sulfhydryl groups/ glutathione
- Tissue engineering: RACS can be used to sort cells for tissue engineering applications, such as creating artificial organs or tissues.
Overall, RACS has the potential to revolutionize many fields by providing a label-free, non-invasive method for sorting and analyzing cells.