Sample Preparation

For any immediate medical service, sample preparation is essential. The advantage of performing on-chip sample preparation is that the entire process is fixed and no manual steps are required. Alfa Chemistry provides customers with professional on-chip sample preparation solutions. We can provide various sample preparation processes according to sample types and diagnostic tests.

At present, Alfa Chemistry has developed several microfluidic sample preparation techniques. These include filtration and separation steps as well as mixing and volumetric metering.

What sample preparation steps are required for your project? Please let us know your requirements.

What we can provide

  • Cell Sorting

For many assays, cell sorting is an important sample preparation step. Alfa Chemistry has many different cell sorting techniques, depending on the type of sample. There are many ways to sort and capture cells for further processing. In this regard, we have the following capabilities:

    • Pinched flow fractionation, a sorting method based on the geometry of microfluidic channels.
    • Dielectrophoresis, in which the electrical properties of cells are used for cell sorting.
    • Acoustic electrophoresis, a cell sorting method based on sound waves.
    • Deterministic lateral displacement (DLD), in which a micropillar array is used to separate cells according to their size and shape.

Sample PreparationFig.1 A schematic showing the cell separation process (Witek M. A, et al. 2020)

  • On-chip Filtration

In most cases, PoC analysis requires a filtering step. This is not only a process of removing particles to prevent condensation in the microfluidic channel, but it is also a necessary step from a diagnostic point of view.

Alfa Chemistry is equipped with a module for separating cellular components from plasma and blood. Our filtration process can be carried out by integrating filtration membranes on the chip in the polymer device. It is also possible to further use a filter membrane with an active ingredient that can bind to the target analyte, such as an antibody.

  • Bead Detection

Bead-based assay is a sample preparation method that can capture target analytes. The coated beads can capture target molecules such as proteins or nucleic acids. Unnecessary materials are removed through an on-chip cleaning step. When capturing genetic material from cells or vesicles, the cells can be lysed by heating or destroying the cells through physical or chemical processes to release DNA/RNA.

Sample PreparationFig.2 Schematic of the magnetic bead cell assay in terms of delayed transit time through two micro Coulter counters. (Liu F, et al. 2016)

  • Volume Metering

Alfa Chemistry uses capillary flow, burst valves, and splitter channels to fill the "containers" on the chip as needed. In this way, a precisely defined volume of liquid can be contained in a defined position of the cartridge, and the liquid will not be released until a specific trigger occurs.

  • Mixing

Mixing is usually also a necessary sample preparation step. Alfa Chemistry is experienced in implementing a variety of solutions that suit the needs of each project. For example, if a highly homogeneous mixture of various substances is required, we can integrate a micromixer or microreactor on the chip.


  • Witek M. A, et al. (2020). "Cell Separations and Sorting." Analytical Chemistry. 92(1): 105-131.
  • Liu F, et al. (2016). "Microfluidic Magnetic Bead Assay for Cell Detection." Analytical Chemistry. 88(1): 711-717.

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