Centrifugal Microfluidics

D.C. Duffy, H.L. Gillis, J. Lin, N.F. Sheppard Jr, and G.J. Kellogg, Microfabricated centrifugal microfluidic systems characterization and multiple enzymatic assays. Anal. Chem. 71, 4669-4678... 

Badr, I.H.A., Johnson, R.D., Madou, M.J., Bachas, L.G., Fluorescent ion-selective optode membranes incorporated onto a centrifugal microfluidics platform. Anal. Chem. 2002, 74(21), 5569-5575. 

The centrifugal microfluidic platform uses inertial and capillary forces on a rotating microstructured substrate for liquid actuation. Relevant inertial (pseudo-) forces include the centrifugal force, Euler force and Coriolis force. The substrate is often disk-shaped. Liquid flow is possible in two dimensions but with the limitation that active liquid transport is always directed radially outwards. Active components can be limited to one rotational axis. 

Figure 11. Passive centrifugal microfluidic valves, (a) Positioning of valves relative to center of rotation and centrifugal force, (b) geometric capillary valve [191], (c) hydrophobic valve [197], (d) centrifugo-pneumatic valve [201]and (e) hydrophihc siphon valve [188].

An overview over centrifugal microfluidic unit operations and related applications can be found in Table 4. 

Table 4 shows some applications that have been realized on the centrifugal microfluidic platform. At the top of the applications section, sample preparation modules (plasma separation, DNA extraction) are shown. This is followed by assays based on the detection of proteins, nucleic acids and small molecules (clinical chemistry). Two additional applications are presented at the end of the table, demonstrating chromatography and protein crystallization. Some instmctive examples are discussed in more detail below. 

TABLE 4. Overview and examples of unit operations and applications for the centrifugal microfluidic platform. 

Also a protein crystallization assay has been demonstrated on the centrifugal microfluidic platform [198]. First, a defined volume of the protein solution is dispensed into the protein inlet and transported into the crystallization chamber. Afterwards, the preloaded precipitant is metered under rotation and transferred into the crystallization chamber as soon as a hydrophobic valve breaks. In the last step, the preloaded oil is released at... 

J. Ducree, S. Haeberle, S. Lutz, S. Pausch, F. v. Stetten, and R. Zengerle, The centrifugal microfluidic Bio-Disk platform. Journal of Micromechanics and Microengineering, vol. 17, no. 7, p. S103-S115, 2007. 

T. Brenner, T. Glatzel, R. Zengerle, and J. Ducree, Frequency-dependent transversal flow control in centrifugal microfluidics, Lab on A Chip, vol. 5, no. 2, pp. 146-150, 2005. 

L. G. Puckett, E. Dikici, S. Lai, M. Madou, L. G. Bachas, and S. Daunert, Investigation into the applicability of the centrifugal microfluidics development of protein-platform for the ligand binding assays incorporating enhanced green fluorescent protein as a fluorescent reporter. Analytical Chemistry, vol. 76, no. 24, pp. 7263-7268, Dec. 2004. 

H. Kido, M. Micic, D. Smith, J. Zoval, J. Norton, and M. Madou, A novel, compact disk-like centrifugal microfluidics system for cell lysis and sample homogenization. Colloids and Surfaces B-Biointerfaces, vol. 58, no. 1, pp. 44-51, 2007. 

Platforms for Lab-on-a-Chip Applications, Centrifugal Microfluidics for Lab-on-a-Chip Applications are also given. 

Centrifugal microfluidics Event triggering Flow control Lab-on-a-disc Valving... 

Centrifugal microfluidic technologies have significantly advanced in both industry and academia over the last decades. While initial focus was... 

RotationaUy Controlled Sacrificial Valves Sacrificial materials have been used for integration of multiplexed assays on centrifugal microfluidic platforms. Compared to geometrical valves, the sacrificial materials also provide a vapor and liquid barrier by physically sealing the microchannels. These sacrificial valves are typically actuated by onboard liquid while the disc is under rotation. At low rotational... 

---