Paper-Powered Synthesis of Gold Nanoparticles and Metronidazole for Bioassays

Here we report on the use of nonaqueous synthesis programming of gold nanoparticles (NPs) and the antibiotic metronidazole using reconfigurable paper comprising an asynchronous modular paperfluidic linear instrument-free (Ampli) chemical plug and play construction set. Liquid fractions and reactions are replaced with paperfluidic membranes on blocks that can be snapped together and disconnected for real time design of experiments. Reagents are embedded into the paper membranes of each block, and reactions are synthesized by snapping together blocks and adding solution, which runs through the blocks in a sequence. Reaction products were characterized by different spectroscopic techniques (Raman spectroscopy, optical absorption spectroscopy, and dynamic light scattering). The resulting products were extracted to form functional NPs used in diagnostic immunoassays, and metronizadole was functional in an antibacterial disk diffusion assay. We investigated how to map off-the-shelf reactions onto individual Ampli blocks and how to successfully generate and extract these products. The paper-based synthesis was faster, significantly more affordable, and lighter than traditional methods, with important implications for local and distributed manufacturing.