A new sample preparation technique for linear dilution gradient with minimal sample utilization and waste generation in DMFBs

Recently, Digital Microfluidic Biochip (DMFB) is developed as a major detection mechanism for biochemical analysis. The technology aims at automation and integration of droplet based microfluidic operation within a miniaturized substrate comprised of 2D planar array of electrodes. Sample preparation remains a major issue for execution of specified bioassay protocols in DMFBs. This requires dilution of samples or formation of mixtures with different targeted concentration factors. Here, we propose new techniques for sample preparation with single source, multiple target concentration having linear dilution gradient for prespecified bioassay execution. The main objective is to i) minimize number of samples as well as reagents for obtaining targeted concentration ii) to employ minimum mixing or dilution operations and thereby optimizing the module utilization and iii) to obtain multiple copies of targeted concentration necessary for fault tolerance and parallel bioassay applications and iv) minimum generation of waste droplets to ensure optimum sample and module utilization.