Programmable nanoparticle patterning by droplet electrophoretic deposition

Here, we demonstrated the printing of a circular pattern of 200 nm nanoparticles by droplet electrophoretic deposition (EPD). For programming the deposition of the pattern, the circular electrode array circuit was designed on a printed circuit board (PCB) based on a polyimide substrate. A 5 μl 200 nm fluorescent nanoparticle suspension (Ex. 505/Em. 515) was dropped onto the PCB for single droplet EPD. For the programmable pattern, a 20 μl nanoparticle suspension was patterned in the shape of a checkerboard and the letter ‘N’ on an array of 4 × 4 electrodes using an expanded droplet EPD. Furthermore, the extended programmable droplet EPD performed respectably on all areas of a 10 × 10 electrodes array when the letters ‘N’, ‘A’, ‘N’, and ‘O’ were patterned. To provide optical transparency with flexibility, the patterned nanoparticles on the PCB were transferred to the polydimethylsiloxane . The extended programmable droplet EPD could provide a simple, fast, two-dimensional maskless patterning fabrication process for nanoparticles such as biomaterials and color quantum dots .