PNNL

Abstract

During the past decades, a variety of two-dimensional (2D) nanosheets have been developed through supramolecular self-assembly. Among them, those assembled from sequence-defined molecules have received particularly attention because they enable a precise displaying of functional groups, including fluorescent dyes, within nanosheet surfaces. On the other hand, due to the fluorescence self-quenching, synthesis of organic 2D nanosheets exhibiting high fluorescence quantum yields is a significant challenge. In this work, we report the utilization of H2S-responsive probes as peptoid sidechains to design and synthesize crystalline 2D nanomembranes (2DNMs) as selective and sensitive H2S sensors. These 2DNM sensors exhibit a high quantum yield as a result of high crystallinity and tunable probe density. Compared with amorphous state of peptoid assembly and pre-assembled peptoid-probe conjugates, these crystalline 2DNM sensors exhibit a significantly strong fluorescence intensity and a high sensitivity (~ 0.36 nM). By sonication-cutting these 2DNM sensors into a colloidal form in aqueous solution, we further demonstrated the use of colloidal 2DNMs for detecting both exogenous and endogenous H2S inside cells or targeted cell organelles. As far as we know, this is the first example of using sequence-defined 2D nanomaterials for selective and sensitive detection of H2S. Because peptoids are biocompatible and peptoid-based 2DNMs are highly programmable, we expect that this new class of 2DNM sensors offer great potentials for detecting H2S and for biological applications.