Design of Multiple Logic Gates Based on Chemically Triggered Fluorescence Switching of Functionalized Polyethylenimine

In this study, two new functionalized polyethylenimine (PEI), PEIR and PEIQ, have been synthesized by covalently conjugating rhodamine 6G (R6G) or 8-chloroacetyl-aminoquinoline (CAAQ) and have been investigated for their sensing capabilities toward metal ions and anions basing on fluorescence on-off and off-on mechanisms. When triggered by protons, metal ions, or anions, functionalized PEIs can behave as a fluorescence switch, leading to a multiaddressable system. Inspired by these results, functionalized PEI-based logic systems capable of performing elementary logic operations (YES, NOT, NOR, and INHIBIT) and integrative logic operations (OR + INHIBIT) have been constructed by observing the change in the fluorescence with varying the chemical inputs such as protons, metal ions, and anions. Due to its characteristics, such as high sensitivity and fast response, developing functionalized PEI as a new material to perform logic operations may pave a new avenue to construct the next generation of molecular devices with better applicability for biomedical research.