Self-suspended Pure Polydiacetylene Nanoparticles with Selective Response to Lysine and Arginine

We demonstrate a very convenient access to self-suspended pure poly(10,12-pentacosadiynoic acid) (PDA) nanoparticles (NPs) simply by adding the ethanol solution of diacetylene monomer to water, followed by UV irradiation. The as-obtained PDA NPs are of high purity because no any initiator, catalyst or stabilizer was used during the whole process. The stabilizer-free PDA NPs are stable in the aqueous suspension. Due to the high purity and stability, the PDA NPs can respond sensitively and selectively to lysine and arginine among 18 kinds of water soluble natural amino acids; without the competitive interaction from the stabilizer, the sensitivity was enhanced.