Novel microsystems for concentration gradient generation through computer optimization with validation using optical instrumentation

Abstract

Novel microfluidic resistive network designs have been evaluated theoretically and experimentally. Such networks are an important component of microreactor technology and are used in analytical and biomedical applications for precisely controlled and evenly stepped dilution. A detailed model and a simplification algorithm have been devised for these networks. Their combination produces novel simplified network designs that exhibit less hierarchical branching over existing network designs. Rapid prediction and optimization of a layout that meets an arbitrary outlet profile is also possible. High levels of linearity were achieved on three microdevice fluidic networks. Good agreement of the experimental results from tested devices with the model was obtained. In addition, CFD simulation of one of the designs gave good agreement with results from the model presented, a good linear outlet profile being obtained.

Droplet Microfluidics for Tumor Drug‐Related Studies and Programmable Artificial Cells

“…b) Hydrophilic Drug A and Drug B dilutions are performed within a microfluidic device. [Chip (shown) fabricated by 3D printing (unpublished data by the authors) for Worldcare Technologies Inc, using the design from, [245,246] )] c) The candidate drug(s) flow into a device with droplet forming junctions which can generate triple emulsions (i.e., droplet incubator) at the outlet. d) Droplet incubators collected into a 24-well plate for further analysis.…”

Concentration gradient generation methods based on microfluidic systems

“…Alternations were put forward to circumvent these problems. [78][79][80][81] For example, Yusuf et al 82 divided the horizontal channel into two parts at the third stage and added a branch at either part, as shown in Fig. 2(b) and (d).…”

Systematic linearisation of a microfluidic gradient network with unequal solution inlet viscosities demonstrated using glycerol

“…The microreactor design has been fabricated according to the layout and channel geometry detailed previously (Abdulla Yusuf et al 2008), and shown in Fig. 1.…”

“…The linearity of the outlet concentration profile is based on the fact that the hydrodynamic resistances of the joint channels (horizontal channels) R H are negligible with respect to those of the serpentines (vertical channels) R v . This was achieved by defining a criteria limit of R v /R H *100:1 (Dertinger et al 2001;Abdulla Yusuf et al 2008). Scaling down the design is therefore possible, provided that the criteria limit has been met; a design with the lowest fabrication limit of the CNC machine (cross-sectional area A = 100 9 100 lm 2 for the serpentines) was initially fabricated.…”

“…The mathematical model for the microfluidic network studied is based on determining the steady state condition of the hydrodynamic variables within the network (Abdulla Yusuf et al 2008), which is mainly achieved through the pressure drop balance within the serpentines on each network level. Thus, low flow rate streams result from the higher mole fraction of the viscous solution in the RHS of the serpentines close to the viscous inlet due to their high hydrodynamic resistances, and vice versa.…”