Linear Dilution Microfluidic Devices
Adrian T. O'Neill and Glenn M. Walker
from: Lab-on-a-Chip Technology (Vol. 1): Fabrication and Microfluidics (Edited by: Keith E. Herold and Avraham Rasooly). Caister Academic Press, U.K. (2009)
Linear dilution is a method to create linearly varying concentrations of a solution. Linear dilutions are commonly used in biological studies where the threshold concentration at which a physiological reaction occurs is unknown, whether it be a minimum effective or a maximum tolerable dosage. In this chapter we present a summary of the approaches used for creating dilutions with microfluidics followed by a detailed methodology for constructing a proportional mixing linear dilution microfluidic device. The microfluidic device presented here is made with a rapid and inexpensive microfabrication method, soft lithography. The device is capable of generating nine linearly varying dilution values with an R2 value exceeding 0.999 and the linearity of the dilutions is independent of the input flowrate, making it a very robust approach to creating linear dilutions. With the model presented the device can be expanded to an arbitrary number of dilutions with commensurate savings in reagent usage and time read more ...