“Indanonalkene” Photoluminescence Platform: Application in Real-Time Tracking the Synthesis, Remodeling, and Degradation of Soft Materials

Abstract

In this Article, we present a strategy to visually track chemically triggered covalent bonding processes in gelation, remodeling, and degradation of soft materials, i.e., hydrogels, based on a new photoluminescence platform. Initially in the development of photoluminophors named "indanonalkenes", turnon emission can be tracked and quantified in the optical reaction between a conjugate acceptor and amine derivatives. On this basis, fluorescence enhancement and mechanical changes were recorded during the gelation process through amine−thiol exchanges under organic and aqueous conditions. Next in macromolecular remodeling, we realized a stimulus-induced transformation of one architecture into another one, exploiting the orthogonality of chemical covalent bonding that could be visualized using luminescence. Furthermore, the hydrogel network can be degraded to release the coupling partner induced by ethylene diamine, and the process can be monitored using fluorescence changes and quantified through gel permeation chromatography, while the released components can be utilized again to regenerate a new hydrogel. In addition, the photographic images provide alternatives to fluorescence spectra and can be digitally processed to quantify the macroscopic changes, resulting in a photographic imaging approach. The real-time observation and quantification of chemically triggered polymeric formation, morphology, and degradation through luminescence in spatial and time scales herald a new generation of "smart" materials.

Fluorometric detection of volatile amines using an indanonalkene platform

“…S5†), through linking four-arm poly(ethylene glycol) thiol with CA-SCH 3 through thiol–thiol scrambling and high cross linking. 29 The scanning electron microscopic (SEM) images of CA-PEG are given in Fig. S6 †.…”

“…Previously, we established a photoluminescent platform based on indanonalkene luminogens (Scheme 1A). 28,29 On this basis, we employed CA-SCH 3 , an indanonalkene molecule containing a bis-vinylogous thioester group, as an amine receptor for the fluorescence detection of volatile amines via aminethiol scrambling (Scheme 1B). [30][31][32] As such, the luminescent precursor CA-SCH 3 was turned on in the presence of ammonia in both solution and solid states to generate the luminophore CA-NH 2 , exhibiting a strong green emission (Scheme 1B).…”

Recent Advances of Chemosensors for Nerve Agents

“…[23][24] Through monitoring the signal changes in colorimetric and fluorometric wavelength or intensity, the presence of nerve agents can be clearly detected by chemosensors with low limit of detection (3σ/k), therefore, these methods had been widely explored in the past decades. [25][26][27][28][29][30][31][32][33][34][35] Due to the fatality of the real nerve agents, it is prohibited to investigate such reagent directly without professional training and biological safety protection third-level laboratory. Thus, common laboratories typically employed the nerve agent simulants with less toxicity, such as diethyl chlorophosphate (DCP), diethyl cyanophosphate (DCNP) to mimic G nerve agents, demeton-S-methyl (DSM) to mimic VX nerve agents as representatives for study.…”

“…Thus, the new optical methods based on chemosensors have attracted much attention due to their molecular diversity, simple operation, low cost, easy portability, real‐time detection, high sensitivity, and high selectivity [23–24] . Through monitoring the signal changes in colorimetric and fluorometric wavelength or intensity, the presence of nerve agents can be clearly detected by chemosensors with low limit of detection (3σ/κ), therefore, these methods had been widely explored in the past decades [25–35] . Due to the fatality of the real nerve agents, it is prohibited to investigate such reagent directly without professional training and biological safety protection third‐level laboratory.…”

Ultrasensitivity Detecting AChE through “Covalent Assembly” and Signal Amplification Strategic Approaches and Applied to Screen Its Inhibitor

“…Moreover, the reaction speed of this self-inductive cascade process should be related to the electron absorption capacity of the conjugated receptor of Meldrum acid derivatives (CA) containing two electron-absorbing groups. The optimal self-inductive cascade process suggested that CAs can be used to enhance the sensitivity of thiols, while other approaches exploit self-triggering polymers, or soft materials, − which selectively release the cleavages of the end groups and trigger the sequential fragmentation to generate multiple reporters.…”