Lab-on-a-chip technology is a rapidly growing area. Lab chips, also called micro total analysis systems (mTAS), perform the tasks of sample pretreatment, separation, and detection all on a single miniature device. And, because of their small size, lab chips consume less reagent and carrier fluid as compared to their macro-scale counterparts. Sample dispersion is a common problem that occurs when a sample plug passes through a channel bend or turn. However, modification of the turn geometry can reduce the effects of dispersion.

Using the electrohydrodynamic (EHD) modeling capabilities of FIDAP, one can easily model sample dispersion in a wide variety of turn geometries. Figure (b) shows the effect of a normal turn on the dispersion of the sample, and (c) shows that constricting the channel radius reduces dispersion. This channel geometry was determined through an iterative process that may have taken weeks or months if one had to design, fabricate and test each new geometry.

Optimization of the microfluidic channel turn geometry reduces sample dispersion. (a) initial condition for (b) and (c), (b) streaking of the sample after encountering a regular turn, and (c) reduction in sample dispersion after constricting the turn radius.