Dual-Labeled Single Fluorescent Probes for the Simultaneous Two-Color Visualization of Dual Organelles and for Monitoring Cell Autophagy.

Dual-labeled single fluorescent probes are powerful tools for studying autophagy on the molecular scale, yet their development has been hampered by design complexity and a lack of valid strategies. Herein, for the first time, we introduce a combinatorial regulation strategy to fabricate dual-labeled probes for studying autophagy by integrating the specific organelle-targeting group and the functional fluorescence switch into a pentacyclic pyrylium scaffold (latent dual-target scaffold). For proof of concept, we prepared a range of dual-labeled probes (TMOs) that display different emission colors in duple organelles. In these probes, TMO1 and TMO2 enabled the simultaneous two-color visualization of the lysosomes and mitochondria. The other probes (TMO3 and TMO4) discriminatively targeted lysosomes/nucleolus and lysosomes/lipid droplets (LDs) with dual-color emission characteristics, respectively. Intriguingly, by simply connecting the endoplasmic reticulum (ER) targeting group to the pentacyclic pyrylium scaffold, we created the first dual-labeled probe TMO5 for simultaneously labeling lysosomes/ER in distinctive fluorescent colors. Subsequently, using the dual-labeled probe TMO2, drug-induced mitophagy was successfully recorded by evaluating the alterations of multiple mitophagy-related parameters, and the mitophagy defects in a cellular model of Parkinson's disease (PD) were also revealed by simultaneous dual-color/dual-organelle imaging. Further, the probe TMO4 can track the movement of lysosomes and LDs in real time and monitor the dynamic process of lipophagy. Therefore, this work not only presents attractive dual-labeled probes to promote the study of organelle interactions during autophagy but also provides a promising combinatorial regulation strategy that may be generalized for designing other dual-labeled probes with multiple organelle combinations.

Size-Switchable Ru Nanoaggregates for Enhancing Phototherapy: Hyaluronidase-Triggered Disassembly to Alleviate Deep Tumor Hypoxia.

Hypoxia is a critical factor for restricting photodynamic therapy (PDT) of tumor, and it becomes increasingly severe with increasing tissue depth. Thus, the relief of deep tumor hypoxia is extremely important to improve the PDT efficacy. Herein, tumor microenvironment (TME)-responsive size-switchable hyaluronic acid-hybridized Ru nanoaggregates (HA@Ru NAs) were developed via screening reaction temperature to alleviate deep tumor hypoxia for improving the tumor-specific PDT by the artful integration multiple bioactivated chemical reactions in situ and receptor-mediated targeting (RMT). In this nanosystem, Ru NPs not only enabled HA@Ru NAs to have near infrared (NIR)-mediated photothermal/photodynamic functions, but also could catalyze endogenous H2O2 to produce O2 in situ. More importantly, hyaluronidase (HAase) overexpressed in the TME could trigger disassembly of HA@Ru NAs via the hydrolysis of HA, offering the smart size switch capability from 60 to 15 nm for enhancing tumor penetration. Moreover, the RMT characteristics of HA ensured that HA@Ru NAs could specially enter CD44-overexpressed tumor cells, enhancing tumor-specific precision of phototherapy. Taken together these distinguishing characteristics, smart HA@Ru NAs successfully realized the relief of deep tumor hypoxia to improve the tumor-specific PDT.

Metallopolysaccharide-Based Smart Nanotheranostic for Imaging-Guided Precise Phototherapy and Sequential Enzyme-Activated Ferroptosis.

Phototheranostic offers a regional-focused tumor treatment upon photoirradiation. However, it is difficult to completely eradicate solid tumors using a conventional phototheranostic owing to the residual tumor cells outside the laser irradiation range. Herein, we fabricated a metallopolysaccharide-based smart nanotheranostic (Fe-dHA) via a nanoassembly-driven method, in which Fe3+ ions were coordinated to dopamine-modified biopolysaccharide hyaluronic acid (dHA). Taking advantage of the structural backbone and intrinsic dual-information-related functions of HA as well as the bi-functional Fe(III)-coordination centers, Fe-dHA can efficiently target tumor cells for phototheranostic. Additionally, it can be activated by endogenous overexpressed hyaluronidase to achieve sequential ferroptosis in tumor cells. The precise imaging and effective tumor inhibition using this metallopolysaccharide-based nanotheranostic were significantly demonstrated in vivo and in vitro. Thus, this rationally designed Fe-dHA provided a simple metallopolysaccharide strategy to develop an "all-in-one" smart nanotheranostic to synergize different therapeutic modalities for improving cancer therapy.

A General Approach to Design Dual Ratiometric Fluorescent and Photoacoustic Probes for Quantitatively Visualizing Tumor Hypoxia Levels In†Vivo.

Herein, we describe an energy balance strategy between fluorescence and photoacoustic effects by sulfur substitution to transform existing hemicyanine dyes (Cy) into optimized NIRF/PA dual ratiometric scaffolds. Based on this optimized scaffold, we reported the first dual-ratio response of nitroreductase probe AS-Cy-NO2 , which allows quantitative visualization of tumor hypoxia in vivo. AS-Cy-NO2 , composed of a new NIRF/PA scaffold thioxanthene-hemicyanine (AS-Cy-1) and a 4-nitrobenzene moiety, showed a 10-fold ratiometric NIRF enhancement (I773 /I733 ) and 2.4-fold ratiometric PA enhancement (PA730 /PA670 ) upon activation by a biomarker (nitroreductase, NTR) associated with tumor hypoxia. Moreover, the dual ratiometric NIRF/PA imaging accurately quantified the hypoxia extent with high sensitivity and high imaging depth in xenograft breast cancer models. More importantly, the 3D maximal intensity projection (MIP) PA images of the probe can precisely differentiate the highly heterogeneous oxygen distribution in solid tumor. Thus, this study provides a promising NIRF/PA scaffold that may be generalized for the dual ratiometric imaging of other disease-relevant biomarkers.

Artificial Metalloprotein Nanoanalogues: In Situ Catalytic Production of Oxygen to Enhance Photoimmunotherapeutic Inhibition of Primary and Abscopal Tumor Growth.

Photoimmunotherapy (PIT) has shown enormous potential in not only eliminating primary tumors, but also inhibiting abscopal tumor growth. However, the efficacy of PIT is greatly limited by tumor hypoxia, which causes the attenuation of phototherapeutic efficacy and is a feature of the immunosuppressive tumor microenvironment (TME). In this study, one type of brand-new artificial metalloprotein nanoanalogues is developed via reasonable integration of a "phototherapy-enzymatic" RuO2 and a model antigen, ovalbumin (OVA) for enhanced PIT of cancers, namely, RuO2 -hybridized OVA nanoanalogues (RuO2 @OVA NAs). The RuO2 @OVA NAs exhibit remarkable photothermal/photodynamic capabilities under the near-infrared light irradiation. More importantly, the photoacoustic imaging and immunofluorescence staining confirm that RuO2 @OVA NAs can remarkably alleviate hypoxia via in situ catalysis of hydrogen peroxide overexpressed in the TME to produce oxygen (O2 ). This ushers a prospect of concurrently enhancing photodynamic therapy and reversing the immunosuppressive TME. Also, OVA, as a supplement to the immune stimulation induced by phototherapy, can activate immune responses. Finally, further combination with the cytotoxic T-lymphocyte-associated protein 4 checkpoint blockade is reported to effectively eliminate the primary tumor and inhibit distant tumor growth via the abscopal effect of antitumor immune responses, prolonging the survival.

Natural Polyphenol-Vanadium Oxide Nanozymes for Synergistic Chemodynamic/Photothermal Therapy.

The selection of suitable nanozymes with easy synthesis, tumor specificity, multifunction, and high therapeutics is meaningful for tumor therapy. Herein, a facile one-step assembly approach was employed to successfully prepare a novel kind of natural polyphenol tannic acid (TA) hybrid with mixed valence vanadium oxide nanosheets (TA@VOx NSs). In this system, VOx is assembled with TA through metal-phenolic coordination interaction to both introduce superior peroxidase-like activity and high near infrared (NIR) absorption owing to partial reduction of vanadium from V5+ to V4+ . The presence of mixed valence vanadium oxide in TA@VOx NSs is proved to be the key for the catalytic reaction of hydrogen peroxide (H2 O2 ) to . OH, and the corresponding catalytic mechanism of H2 O2 by TA@VOx NSs is proposed. Benefitting from such peroxidase-like activity of TA@VOx NSs, the overproduced H2 O2 of the tumor microenvironment allows the realization of tumor-specific chemodynamic therapy (CDT). As a valid supplement to CDT, the NIR absorption enables TA@VOx NSs to have NIR light-mediated conversion ability for photothermal therapy (PTT) of cancers. Furthermore, in vitro and in vivo experiments confirmed that TA@VOx NSs can effectively inhibit the growth of tumors by synergistic CDT/PTT. These results offer a promising way to develop novel vanadium oxide-based nanozymes for enhanced synergistic tumor-specific treatment.

Recent Advances in Carbon Nanomaterials for Cancer Phototherapy.

Carbon nanomaterials have received great attention from the scientific community over the past few decades because of their unique physical and chemical properties. In this minireview, we will summarize the recent progress of the use of various carbon nanomaterials in the field of cancer phototherapy. The structural characteristics of each category and the surface functionalization strategies of these nanomaterials will be briefly introduced before focusing on their therapeutic applications. Recent advances on their use in photothermal therapy, photodynamic therapy, and combined phototherapies are presented. Moreover, a few challenges and perspectives on the development of carbon nanomaterials for future theranostics are also discussed.

Hypericin-Loaded Carbon Nanohorn Hybrid for Combined Photodynamic and Photothermal Therapy in Vivo.

Photodynamic therapy (PDT) of hypericin (Hyp) is hampered by poor water solubility and photostability. Incorporation of photosensitizers into nanocarriers has been designed to solve these issues. Herein, SWNH-Hyps nanohybrids were first fabricated by loading hypericin on the surface of single-walled carbon nanohorns (SWNHs) through ??? interaction and exhibited high solubility and stability in aqueous water. SWNH-Hyps could be utilized for a single platform for cancer therapy because it could simultaneously generate enough reactive oxygen species and hyperthermia using light irradiation. Moreover, the SWNHs not only improved water solubility, photostability, and therapy effects of Hyp but also protected it from light degradation. SWNH-Hyps could effectively ablate 4T1 cells by photodynamic/photothermal synergistic therapy upon 590 and 808 nm light irradiations compared with PDT. Furthermore, remarkable tumor cell death as well as tumor growth inhibition was proved via photothermal therapy and PDT of SWNH-Hyps under 590 and 808 nm light irradiations, which demonstrated that synergistic anticancer ability of SWNH-Hyps was better than that of free Hyp in vivo. Such a simple and facile adsorption method improved water solubility of Hyp and then enhanced its therapy effect, which displays that SWNHs can be hopefully used in medicines in the future.

Near-Infrared Light Responsive Imaging-Guided Photothermal and Photodynamic Synergistic Therapy Nanoplatform Based on Carbon Nanohorns for Efficient Cancer Treatment.

Indocyanine green (ICG) is an effective light absorber for laser-mediated photodynamic therapy. However, applications of ICG are limited due to its rapid degradation and poor photostability in water. Herein, we report the development of a multifunctional nanoplatform by coating ICG on the surface of single-walled carbon nanohorns (SWNHs) through π-π stacking, obtaining SWNH-ICGs with high solubility and stability under physiological conditions. The SWNH-ICGs could be used as a single nanoplatform to simultaneously produce satisfactory hyperthermia and reactive oxygen species under near-infrared (NIR) laser irradiation. In addition, the SWNH-ICGs not only improved the photostability of ICG in different media, but also protected it from light degradation. The SWNH-ICGs exhibited highly efficient thermal/photoacoustic (PA) imaging-guided photothermal therapy (PTT) and photodynamic therapy (PDT) effects, even under low-power laser irradiation (0.3 W cm-2 ) in vitro. Combined PTT and PDT effectively killed triple-negative breast cancer 4T1 cells, demonstrating a markedly improved and synergistic therapeutic effect compared to PTT or PDT alone. Furthermore, significant tumor growth inhibition as well as tumor cell death were observed following PTT/PDT at 808 nm laser irradiation, confirming the synergistic effects of SWNH-ICGs over free ICG in vivo. This facile and simple methodology for thermal/PA imaging-guided PTT/PDT suggests that SWNH-ICGs may serve as an effective nanoplatform for cancer therapy.

Poly(N-phenylglycine)-Based Nanoparticles as Highly Effective and Targeted Near-Infrared Photothermal Therapy/Photodynamic Therapeutic Agents for Malignant Melanoma.

Malignant melanoma is a highly aggressive tumor resistant to chemotherapy. Therefore, the development of new highly effective therapeutic agents for the treatment of malignant melanoma is highly desirable. In this study, a new class of polymeric photothermal agents based on poly(N-phenylglycine) (PNPG) suitable for use in near-infrared (NIR) phototherapy of malignant melanoma is designed and developed. PNPG is obtained via polymerization of N-phenylglycine (NPG). Carboxylate functionality of NPG allows building multifunctional systems using covalent bonding. This approach avoids complicated issues typically associated with preparation of polymeric photothermal agents. Moreover, PNPG skeleton exhibits pH-responsive NIR absorption and an ability to generate reactive oxygen species, which makes its derivatives attractive photothermal therapy (PTT)/photodynamic therapy (PDT) dual-modal agents with pH-responsive features. PNPG is modified using hyaluronic acid (HA) and polyethylene glycol diamine (PEG-diamine) acting as the coupling agent. The resultant HA-modified PNPG (PNPG-PEG-HA) shows negligible cytotoxicity and effectively targets CD44-overexpressing cancer cells. Furthermore, the results of in vitro and in vivo experiments reveal that PNPG-PEG-HA selectively kills B16 cells and suppresses malignant melanoma tumor growth upon exposure to NIR light (808 nm), indicating that PNPG-PEG-HA can serve as a very promising nanoplatform for targeted dual-modality PTT/PDT of melanoma.

Selective Probing of Gaseous Ammonia Using Red-Emitting Carbon Dots Based on an Interfacial Response Mechanism.

Solid-state fluorescence sensing is one of the most appealing detection techniques because of its simplicity and convenience in practical operation. Herein, we report the development of a red-emitting carbon dots (RCDs)-based material as a solid-state fluorescence sensor for the selective probing of gaseous ammonia. The RCDs were prepared by a low-cost, one-step carbonization method using sugar cane bagasse as the carbon precursor. The pristine RCDs were then directly coated on polyvinylidene fluoride membrane to produce a new fluorescence sensor capable of selectively distinguishing toxic gaseous ammonia from other analyte vapors through sensitive fluorescence quenching with a low detection limit. More importantly, the interfacial response mechanism occurring on the surface of the RCDs has been studied by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and Raman measurements. The results indicate that fluorescence quenching in the RCDs might result from ammonia-induced Michael addition through insertion of N into the C=C group and deprotonation of the carboxyl group. To the best of our knowledge, this is the first report that provides clear insight into the mechanism of surface chemistry on CDs in the solid state.

Acidity-responsive polyphenol-coordinated nanovaccines for improving tumor immunotherapy via bidirectional reshaping of the immunosuppressive microenvironment and controllable release of antigens.

The tumor immunosuppressive microenvironment (TIME) and uncontrollable release of antigens can lower the efficacy of nanovaccine-based immunotherapy (NBI). Therefore, it is necessary to develop a new strategy for TIME reshaping and controllable release of antigens to improve the NBI efficacy. Herein, an acidity-responsive Schiff base-conjugated polyphenol-coordinated nanovaccine was constructed for the first time to realize bidirectional TIME reshaping and controllable release of antigens for activating T cells. In particular, an acidity-responsive tannic acid-ovalbumin (TA-OVA) nanoconjugate was prepared via a Schiff base reaction. FeIII was coordinated with TA-OVA to produce a FeIII-TA-OVA nanosystem, and 1-methyltryptophan (1-MT) as an indoleamine 2,3-dioxygenase inhibitor was loaded to form a polyphenol-coordinated nanovaccine. The coordination between FeIII and TA could cause photothermal ablation of primary tumors, and the acidity-triggered Schiff base dissociation of TA-OVA could controllably release OVA to realize lysosome escape, initiating the body's immune response. More importantly, oxidative stress generated by a tumor-specific Fenton reaction of Fe ions could promote the polarization of tumor-associated macrophages from the M2 to M1 phenotype, resulting in the upregulation of cytotoxic T cells and helper T cells. Meanwhile, 1-MT could downregulate immunosuppressive regulatory T cells. Overall, such skillful combination of bidirectional TIME reshaping and controllable antigen release into one coordination nanosystem could effectively enhance the NBI efficacy of tumors.

Surface-Initiated Polymerization with an Initiator Gradient: A Monte Carlo Simulation.

Due to the difficulty of accurately characterizing properties such as the molecular weight (Mn) and grafting density (σ) of gradient brushes (GBs), these properties are traditionally assumed to be uniform in space to simplify analysis. Applying a stochastic reaction model (SRM) developed for heterogeneous polymerizations, we explored surface-initiated polymerizations (SIPs) with initiator gradients in lattice Monte Carlo simulations to examine this assumption. An initial exploration of SIPs with 'homogeneously' distributed initiators revealed that increasing σ slows down the polymerization process, resulting in polymers with lower molecular weight and larger dispersity (D) for a given reaction time. In SIPs with an initiator gradient, we observed that the properties of the polymers are position-dependent, with lower Mn and larger D in regions of higher σ, indicating the non-uniform properties of polymers in GBs. The results reveal a significant deviation in the scaling behavior of brush height with σ compared to experimental data and theoretical predictions, and this deviation is attributed to the non-uniform Mn and D.

Copper-Nitrogen-Coordinated Carbon Dots: Transformable Phototheranostics from Precise PTT/PDT to Post-Treatment Imaging-Guided PDT for Residual Tumor Cells.

Phototheranostics has attracted considerable attention in the fields of cancer diagnosis and treatment. However, the complete eradication of solid tumors using traditional phototheranostics is difficult because of the limited depth and range of laser irradiation. New phototheranostics enabling precise phototherapy and post-treatment imaging-guided programmed therapy for residual tumors is urgently required. Accordingly, this study developed a novel transformable phototheranostics by assembling hyaluronic acid (HA) with copper-nitrogen-coordinated carbon dots (CDs). In this transformable nanoplatform, named copper-nitrogen-CDs@HA, the HA component enables the specific targeting of cluster determinant (CD) 44-overexpressing tumor cells. In the tumor cells, redox glutathione converts Cu(II) (cupric ions) into Cu(I) (cuprous ions), which confers the novel transformable functionality to phototheranostics. Both in vitro and in vivo results reveal that the near-infrared-light-photoactivated CuII-N-CDs@HA could target CD44-overexpressing tumor cells for precise synergistic photothermal therapy and photodynamic therapy. This study is the first to observe that CuII-N-CDs@HA could escape from lysosomes and be transformed in situ into CuI-N-CDs@HA in tumor cells, with the d9 electronic configuration of Cu(II) changing to the d10 electronic configuration of Cu(I), which turns on their fluorescence and turns off their photothermal properties. This transformable phototheranostics could be used for post-treatment imaging-guided photodynamic therapy on residual tumor cells. Thus, the rationally designed copper-nitrogen-coordinated CDs offer a simple in situ transformation strategy for using multiple-stimulus-responsive precise phototheranostics in post-treatment monitoring of residual tumor cells and imaging-guided programmed therapy.

Hydrogen Sulfide Gas Amplified ROS Cascade: FeS@GOx Hybrid Nanozyme Designed for Boosting Tumor Chemodynamic Immunotherapy.

Chemodynamic immunotherapy that utilizes catalysts to produce reactive oxygen species (ROS) for killing tumor cells and arousing antitumor immunity has received considerable attention. However, it is still restricted by low ROS production efficiency and insufficient immune activation, due to intricate redox homeostasis in the tumor microenvironment (TME). Herein, a metalloprotein-like hybrid nanozyme (FeS@GOx) is designed by in situ growth of nanozyme (ferrous sulfide, FeS) in a natural enzyme (glucose oxidase, GOx) to amplify ROS cascade for boosting chemodynamic immunotherapy. In FeS@GOx, GOx allows the conversion of endogenous glucose to gluconic acid and hydrogen peroxide, which provides favorable increasing hydrogen peroxide for subsequent Fenton reaction of FeS nanozymes, thus reinforcing ROS production. Notably, hydrogen sulfide (H2 S) release is activated by the gluconic acid generation-related pH decrease, which can suppress the activity of endogenous thioredoxin reductase and catalase to further inhibit ROS elimination. Thus, FeS@GOx can sustainably amplify ROS accumulation and perturb intracellular redox homeostasis to improve chemodynamic therapy and trigger robust immunogenic cell death for effective immunotherapy combined with immune checkpoint blockade. This work proposes a feasible H2 S amplified ROS cascade strategy employing a bioinspired hybrid nanozyme, providing a novel pathway to multi-enzyme-mediated TME modulation for precise and efficient chemodynamic immunotherapy.

In Situ Polymerization of Aniline Derivative in Vivo for NIR-II Phototheranostics of Tumor.

Natural biopolymers can be controllably in situ synthesized in organisms and play important roles in biological activities. Inspired by this, the manipulation of in situ biosynthesis of functional polymers in vivo will be an important way to obtain materials for meeting biological requirements. Herein, in situ biosynthesis of functional conjugated polymer at the tumor site was achieved via the utilization of specific tumor microenvironment (TME) characteristics for the first time. Specially, a water-soluble aniline dimer derivative (N-(3-sulfopropyl) p-aminodiphenylamine, SPA) was artfully in situ polymerized into polySPA (PSPA) nanoparticles at the tumor site, which was activated via the catalysis of hydrogen peroxide (H2O2) overexpressed in TME to produce hydroxyl radical (•OH) by coinjected horseradish peroxidase (HRP). Benefiting from outstanding near-infrared (NIR)-II absorption of PSPA, the in situ polymerization process can be validly monitored by photoacoustic (PA) signal at the NIR-II region. Meanwhile, in situ polymerization would induce the size of polymeric materials from small to large, improving the distribution and retention of PSPA at the tumor site. On the combination of NIR-II absorption of PSPA and the size variation induced by polymerization, such polymerization can be applied for tumor-specific NIR-II light mediated PA image and photothermal inhibition of tumors, enhancing the precision and efficacy of tumor phototheranostics. Therefore, the present work opens the way to manipulate TME-activated in situ biosynthesis of functional conjugated polymer at the tumor site for overcoming formidable challenges in tumor theranostics.

Calixarene-induced aggregation of perylene bisimides.

The complex-induced aggregation of perylene bisimides by p-sulfonatocalix[n]arenes was studied, where the aggregation stability, aggregation distance, as well as the degree of order of aggregation were all improved.

A Simple Stochastic Reaction Model for Heterogeneous Polymerizations.

The stochastic reaction model (SRM) treats polymerization as a pure probability-based issue, which is widely applied to simulate various polymerization processes. However, in many studies, active centers were assumed to react with the same probability, which cannot reflect the heterogeneous reaction microenvironment in heterogeneous polymerizations. Recently, we have proposed a simple SRM, in which the reaction probability of an active center is directly determined by the local reaction microenvironment. In this paper, we compared this simple SRM with other SRMs by examining living polymerizations with randomly dispersed and spatially localized initiators. The results confirmed that the reaction microenvironment plays an important role in heterogeneous polymerizations. This simple SRM provides a good choice to simulate various polymerizations.

H2O2-activated in situ polymerization of aniline derivative in hydrogel for real-time monitoring and inhibition of wound bacterial infection.

Wound is highly susceptible to bacterial infection, which can cause chronic wound and serial complications. However, timely treatment is hampered by the lack of real-time monitoring of wound status and effective therapeutic systems. Herein, in situ biosynthesis of functional conjugated polymer in artificial hydrogel was developed via the utilization of biological microenvironment to realize monitoring in real time of wound infection and inhibition of bacteria for the first time. Specially, an easily polymerizable aniline dimer derivative (N-(3-sulfopropyl) p-aminodiphenylamine, SPA) was artfully in situ polymerized into polySPA (PSPA) in calcium alginate hydrogel, which was initiated via the catalysis of hydrogen peroxide (H2O2) overexpressed in infected wound to produce hydroxyl radical (•OH) by preloaded horseradish peroxidase (HRP). Benefitting from outstanding near infrared (NIR) absorption of PSPA, such polymerization can be ingeniously used for real-time monitoring of H2O2 via naked-eye and photoacoustic signal, as well as NIR light-mediated photothermal inhibition of bacteria. Furthermore, combining the persistent chemodynamic activity of •OH, the in vivo experimental data proved that the wound healing rate was 99.03% on the 11th day after treatment. Therefore, the present work opens the way to manipulate in situ biosynthesis of functional conjugated polymer in artificial hydrogels for overcoming the issues on wound theranostics.

Reversible and selective sensing of aniline vapor by perylene-bridged bis(cyclodextrins) assembly.

Detecting volatile amines is a significant topic in quality control of food and medical diagnosis. Selectively sensing a given gaseous amine from other analogues, however, still remains a formidable challenge in solid-state fluorescence sensing because of the lack of specialized binding sites. Herein, we demonstrate a new supramolecular strategy for selectively sensing aniline based on the aggregation of perylene-cyclodextrin conjugate 1. Compared with our previous results based on perylene-bridged bis(permethyl-ß-cyclodextrins), the present system achieves a pronounced improvement of both selectivity and reversibility. The sensory material was constructed from the π-stacking aggregate of 1 embedded in poly(vinylidene fluoride) membrane, which ensures benign solid-state fluorescence with potential amplification mechanism as well as convenient preparation and practical operation. Grafting cyclodextrin receptors endows the sensory material with desired selectivity as a result of diverse binding abilities. Especially, the thermodynamically reversible host-guest inclusion leads to the excellent sensing reversibility. The present research opens the way to build new n-type fluorescence sensory materials for detecting volatile amines instantly with compelling selectivity, sensitivity, and reversibility.