The molecular diagnosis field has truly evolved in recent years thanks to the development of bead-based flow cytometry techniques. Magnetic beads are highly customizable since variable molecular targets can be attached to them, from DNA to proteins, which allows a versatile application. Using a flow cytometry technique, the beads bound to their targets can be separated and individually analyzed. The advantages provided by this technique are the increase of targets being analyzed simultaneously due to the tridimensional nature of the beads, the reduction in analysis and isolation time, and since the beads’ composition and targets are customizable it is possible to gather several analysis parameters in one single preparation.
One example of this technique was developed by Yang and colleagues that created a microfluidics version of a flow cytometer that allows the integration of several devices to purify viral samples in a microfluidic approach. In this protocol, the magnetic beads are coupled with antibodies specific for virus epitopes in order to capture viruses and another set of dye-labeled antibodies is used for detection of the bound viral particles. Then, with the creation of a microfluidics chip, the researchers were able to integrate an incubation module, a flow cytometry module and an optical detection module into a single device. With this chip the virus immunoassay is optimized in a way that allows purifying, counting and collecting viruses in a single step protocol. The limit of detection for the viral samples was 103 PFU/ml and it took only 40 minutes to perform, which makes this procedure an important tool for rapid diagnosis.
The development of this procedure shows the potential of magnetic beads to provide a technological stepping stone for making diagnosis tools more powerful and efficient with virtually no setbacks.
Micro flow cytometry utilizing a magnetic bead-based immunoassay for rapid virus detection.Yang, S. Y., Lien, K. Y., Huang, K. J., Lei, H. Y., & Lee, G. B. (2008). Biosensors and Bioelectronics, 24, 855–862. doi:10.1016/j.bios.2008.07.019
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