Dielectrophoresis-based 'Lab-on-a-chip' devices for programmable binding of microspheres to target cells.

There is a general agreement on the fact that the Laboratory on chip (Lab-on-a-chip) technology will enable laboratory testing to move from laboratories employing complex equipments into non-laboratory settings. In this respect, dielectrophoresis (DEP) is a very valuable approach to design and produce Lab-on-a-chip devices able to manipulate microparticles and cells. In this study, we report the application of DEP-based devices for facilitating programmable interactions between microspheres and target tumor cells. We used two Lab-on-a-chip devices, one (the SmartSlide) carrying 193 parallel electrodes and generating up to 50 cylinder-shaped DEP cages, the other (the DEP array) carrying 102,400 arrayed electrodes and generating more than 10,000 spherical DEP cages. We determined whether these devices can be used to levitate and move microspheres and cells in order to obtain a forced interaction between microspheres and target cells. The first major point of this manuscript is that the DEP-based SmartSlide can be used for transfection experiments in which microspheres and target cells are forced to share the same DEP cage, leading to efficient binding of the microspheres to target cells. The data obtained using the DEP array show that this system allows the sequential, software-controlled binding of individually and independently moved single microspheres to a single target tumor cell. To our knowledge, this is the first report on the possible use of a DEP-based Lab-on-a-chip device for guided multiple binding of singularly moved microspheres to a single tumor cell. This approach can be of interest in the field of drug discovery, delivery and diagnosis.