Self-assembled heterogeneous integrated fluorescence detection system

We present the current progress towards a fully integrated fluorescence detection system constructed via self-assembly of independently microfabricated excitation sources and photosensors onto a common template. The system template contains specifically shaped binding sites for micron-scale components and electrical interconnects. The self-assembly process allows for using materials such as plastic or glass for constructing the template that are incompatible with conventional microfabrication processes. The excitation sources are AlGaAs light emitting diodes and the photosensors are silicon pn junctions. These microcomponents are independently microfabricated and released from their respective substrates to yield a powder-like collection. The microcomponents are introduced over the template in a heated fluidic slurry and allowed to self-assemble onto the complementary-shaped binding sites. The self-assembly process is driven by capillary forces resultant from low melting point alloy coated on the electrical contact pads, fluidic forces, shape matching, and gravity. The final system offers a 3 x 3 array of individually addressable complete fluorescence detection units.