In this work, we present a novel facile strategy for green synthesis of polyethyleneimine (PEI)-capped carbon dots (PEI-CDs), in which citric acid and PEI were chosen as reactants and highly fluorescent PEI-CDs could be readily obtained via a simple one-pot refluxing under 120 • C within 2 H. Fluorescence studies indicate that the as-prepared PEI-CDs exhibit strong fluorescence emission at 446 nm with excitation at 365 nm. Upon the sequential addition of Cu 2+ and H 2 S, PEI-CDs result in an interesting "ON−OFF−ON" three-state emission responses, promising a bifunctional sensory platform. Moreover, the Cu 2+ /H 2 S-facilated reversible fluorescence changes of PEI-CDs have demonstrated the design of an INHIBIT logic system based on Boolean logic.

This letter reports on a novel cost-efficient and multifunctional barcode-like sensors array (BLSA) printed with a conductive bioinspired smart ink. The conductive  ink (P@G ink), which can be further chemically engineered with different organic ligands, was generated via facile one-pot hydrothermal reduction of graphene oxide (GO) in dopamine (DA) as coreductan Usingvarious  chemical derivatives of the P@G inks on a flexible substrate (e.g., Kapton), a highly integrated BLSA as well as smart nose/tongue mimic array were generated for simultaneous sensing and distinguishing of complex physical and chemical stimuli, including temperature, light, air pressure, relative humidity, and volatile organic compounds (VOCs). Due to these very attractive features, the reported P@G ink-based BLSA would have the potential for unique opportunities regarding “all-in-one”—yet cost-effective—disposable electronics and sensors.

A sensor array mimicking a chemical nose/tongue based on bovine serum albumin nanoparticles (BSANsn) has been developed for fluorescent pattern recognition of metal ions in biofluids. Three types of BSANsn...