Hyperbranched Poly(amido amine) Entrapped Tetraphenylethene as a Fluorescence Probe for Sequential Quadruple-Target Detection and Its Potential as a Chemical Logic Gate.

Fluorescence sensors exhibit great potential as molecular logic gates to perform computation on a nanometer scale. For achieving the more complex artificial intelligence activities, developing complex logic gates using multitarget sensing systems with multi-input characteristics is highly desirable. Herein, a water-soluble quadruple-target fluorescence sensor that embeds a small amount (4.1 wt %) of tetraphenylethene (TPE) units into hyperbranched poly(amido amine) (TPE-HPA) has been designed. The nonfluorescent TPE-HPA could experience the fluorescence "off-on-off-on-off" by sequential addition of sodium hexametaphosphate (SHMP), Fe3+, ascorbic acid (AA), and H2O2. The as-prepared quadruple-target sensor showed good sensitivity and selectivity to SHMP, Fe3+, AA, and H2O2, and the limit of detection values were 29 nM, 20 nM, 0.66 μM, and 0.78 μM, respectively. On the basis of the multitarget sensing nature of TPE-HPA, chemical or electrochemical-induced logic gates were constructed, including YES, NOT, OR, NOR, NAND, INHIBIT, IMP, and higher logic systems.