Biomedical Engineering Reference
In-Depth Information
F
LF FHFLF
Unintentionally
activated cells
F
H
F
L
F
F
H
F
1
4
Destination
cells
2
Electrode
Interference
3
Figure 3.13
An example to illustrate the problem of electrode interference. H/L stands for high/low volt-
age pairs to activate the cells, and unselected row/column pins are left floating (F).
3.2.2 Power-efficient interference-Free Droplet Manipulation
based on Destination-Cell Categorization
In this subsection, we focus on the problem of manipulating multiple drop-
lets based on digital microfluidic biochips that use cross-referencing to
address the electrodes.
3.2.2.1 Electrode Interference
For the concurrent manipulation of multiple droplets on a cross-referencing-
based biochip, multiple row and column pins must be selected to activate the
destination cells, that is, cells to which the droplets are supposed to move.
However, the selected row and column pins may also result in the activation
of cells other than the intended droplet destinations. An example is shown
in Figure 3.13. The goal here is to route Droplets 1, 2, and 3 simultaneously to
their destination cells. Droplet 4 is supposed to remain in its current location.
However, two additional cells are activated unintentionally when the acti-
vation voltage is applied to the row and column pins corresponding to the
destination cells. As a result, Droplet 4 is unintentionally moved one cell up
(along the Y-direction).
3.2.2.2 Fluidic Constraints
Droplet manipulations must also conform to rules referred to as the fluidic
constraints. These constraints are given by a set of inequalities, as shown in
Subsection 3.1.1.
3.2.2.3 Destination-Cell Categorization
A s s h of w in i in F i g u r e 3.13, t h e c of in c u r r e in t m a in i p u l at i of in of f mu lt i pl e d r of pl e t s mu s t
be carried out without introducing any electrode interference. For simplicity,
