Carbon dioxide (CO2) is a detrimental greenhouse gas to the environment as the main contributor to global warming. However, the development of efficient methods for CO2 absorption and separation is still a great challenge. Ionic liquids (ILs) have emerged as promising solvents for CO2 separation due to negligible vapor pressure and adjustable structures. In this work, a new strategy that three superbase ILs are designed as hydrogen bond acceptor (HBA) and further combined with ethylene glycol (EG) as hydrogen bond donor (HBD) to form novel IL-based deep eutectic solvents (DESs) was proposed for efficient and reversible absorption of CO2. The results indicated that both excellent recyclability and high CO2 mass capacity up to 0.141 g CO2/g DES under 40 °C and 100 kPa are achieved by [HDBU]­[Im]/EG with the mass ratio of 7:3, and the value is much higher than those of most of the reported IL-based DESs. The superior CO2 absorption and desorption performances were attributed to the synergistic interaction between both IL and EG with CO2 to form carbamate and carbonate, respectively. This work provides a feasible method for designing IL-based solvents in CO2 separation applications.

Viral cancers show oncogene addiction to viral oncoproteins, which are required for survival and proliferation of the dedifferentiated cancer cell. Human Merkel cell carcinomas (MCCs) that harbor a clonally integrated Merkel cell polyomavirus (MCV) genome have low mutation burden and require viral T antigen expression for tumor growth. Here, we showed that MCV+ MCC cells cocultured with keratinocytes undergo neuron-like differentiation with neurite outgrowth, secretory vesicle accumulation, and the generation of sodium-dependent action potentials, hallmarks of a neuronal cell lineage. Cocultured keratinocytes are essential for induction of the neuronal phenotype. Keratinocyte-conditioned medium was insufficient to induce this phenotype. Single-cell RNA sequencing revealed that T antigen knockdown inhibited cell cycle gene expression and reduced expression of key Merkel cell lineage/MCC marker genes, including HES6, SOX2, ATOH1, and KRT20. Of these, T antigen knockdown directly inhibited Sox2 and Atoh1 expression. MCV large T up-regulated Sox2 through its retinoblastoma protein-inhibition domain, which in turn activated Atoh1 expression. The knockdown of Sox2 in MCV+ MCCs mimicked T antigen knockdown by inducing MCC cell growth arrest and neuron-like differentiation. These results show Sox2-dependent conversion of an undifferentiated, aggressive cancer cell to a differentiated neuron-like phenotype and suggest that the ontology of MCC arises from a neuronal cell precursor.

Protic ionic liquids (PILs) are considered as potential solvents for CO 2 capture due to their simple synthetic routes and unique properties. In this work, three low viscous PILs, tetramethylgunidinium imidazole ([TMGH][Im]), tetramethylgunidinium pyrrole ([TMGH][Pyrr]) and tetramethylgunidinium phenol ([TMGH][PhO]) were synthesized and the effect of anions, temperature, CO 2 partial pressure and water content on CO 2 absorption performance of PILs was also systematically studied. It was found that the PILs with larger basicity show higher CO 2 absorption capacity, and [TMGH][Im] simultaneously shows relatively high absorption rate and CO 2 absorption capacity of 0.154 g CO 2 /g IL at 40 ℃, 1 bar. The addition of H 2 O has a positive effect on gravimetric absorption capacity of CO 2 at the range of 0-20 wt% H 2 O, and the highest capacity of 0.186 g CO 2 /g IL was achieved as the water content was 7 wt%. In-situ FTIR, 13 C NMR and theoretical calculations verified that more stable bicarbonate are produced during CO 2 absorption by [TMGH][Im]-H 2 O system. However, neat [TMGH][Im] can react with CO 2 to form the reversible carbamate, leading to excellent recyclability after four absorption-desorption cycles. The results implied that neat [TMGH][Im] shows great potentials in CO 2 absorption applications.

We report ac rystallization-induced emission fluorophore to quantitatively interrogate the polarity of aggregated proteins.T his solvatochromic probe,n amely "AggRetina" probe,i nherently binds to aggregated proteins and exhibits both ap olarity-dependent fluorescence emission wavelength shift and aviscosity-dependent fluorescence intensity increase. Regulation of its polarity sensitivity was achieved by extending the conjugation length. Different proteins bear diverse polarity upon aggregation, leading to different resistance to proteolysis. Polarity primarily decreases during protein misfolding but viscosity mainly increases upon the formation of insoluble aggregates.Wequantified the polarity of aggregated protein-ofinterest in live cells via HaloTag bioorthogonal labeling, revealing polarity heterogeneity within cellular aggregates. The enriched micro-environment details inside misfolded and aggregated proteins may correlate to their bio-chemical properties and pathogenicity.

Stress-induced intracellular proteome aggregation is a hallmark and a biomarker of various human diseases. Current sensors requiring either cellular fixation or covalent modification of the entire proteome are not suitable for live-cell applications and dynamics study. Herein, we report a noncovalent, cell-permeable, and fluorogenic sensor that can reversibly bind to proteome amorphous aggregates and monitor their formation, transition, and clearance in live cells. This sensor was structurally optimized from previously reported fluorescent protein chromophores to enable noncovalent and reversible binding to aggregated proteins. Unlike all previous sensors, the noncovalent and reversible nature of this probe allows for dynamic detection of both the formation and clearance of aggregated proteome in one live-cell sample. Under different cellular stresses, this sensor reveals drastic differences in the morphology and location of aggregated proteome. Furthermore, we have shown that this sensor can detect the transition from proteome liquid-to-liquid phase separation to liquid-to-solid phase separation in a two-color imaging experiment. Overall, the sensor reported here can serve as a facile tool to screen therapeutic drugs and identify cellular pathways that ameliorate pathogenic proteome aggregation in live-cell models.

Unlike amyloid aggregates, amorphous protein aggregates with no defined structures have been challenging to target and detect in a complex cellular milieu. In this study, we rationally designed sensors of amorphous protein aggregation from aggregation‐induced‐emission probes (AIEgens). Utilizing dicyanoisophorone as a model AIEgen scaffold, we first sensitized the fluorescence of AIEgens to a nonpolar and viscous environment mimicking the interior of amorphous aggregated proteins. We identified a generally applicable moiety (dimethylaminophenylene) for selective binding and fluorescence enhancement. Regulation of the electron‐withdrawing groups tuned the emission wavelength while retaining selective detection. Finally, we utilized the optimized probe to systematically image aggregated proteome upon proteostasis network regulation. Overall, we present a rational approach to develop amorphous protein aggregation sensors from AIEgens with controllable sensitivity, spectral coverage, and cellular performance.

Phototherapy exhibits significant potential as a novel tumor treatment method, and the development of highly active photosensitizers and photothermal agents has drawn considerable attention. In this work, S and N atom co-doped carbon dots (S,N-CDs) with an absorption redshift effect were prepared by hydrothermal synthesis with lysine, o-phenylenediamine, and sulfuric acid as raw materials. The near-infrared (NIR) absorption features of the S,N-CDs resulted in two-photon (TP) emission, which has been used in TP fluorescence imaging of lysosomes and tumor tissue pH and real-time monitoring of apoptosis during tumor phototherapy, respectively. The obtained heteroatom co-doped CDs can be used not only as an NIR imaging probe but also as an effective photodynamic therapy/photothermal therapy (PDT/PTT) therapeutic agent. The efficiencies of different heteroatom-doped CDs in tumor treatment were compared. It was found that the S,N-CDs showed higher therapeutic efficiency than N-doped CDs, the efficiency of producing 1O2 was 27%, and the photothermal conversion efficiency reached 34.4%. The study provides new insight into the synthesis of carbon-based nanodrugs for synergistic phototherapy and accurate diagnosis of tumors.

Tumor microenvironment (TME)‐activated cancer imaging and therapy is a key to achieving accurate diagnosis and treatment of cancer and reducing the side effects. Herein, smart near‐infrared carbon dot‐metal organic framework MIL‐100 (Fe) assemblies are constructed to achieve TME‐activated cancer imaging and chemodynamic‐photothermal combined therapy. First, a near‐infrared emission carbon dot (RCDs) is developed using glutathione (GSH) as the precursor. Then, the RCDs@MIL‐100 self‐assemblies are obtained using RCDs, FeCl3, and trimesic acid solutions as raw materials. After the RCDs@MIL‐100 enters the TME, a high concentration of GSH reduces Fe3+ to Fe2+ and drains the GSH, triggering the collapse of RCDs@MIL‐100 skeleton and the release of RCDs and Fe2+, at which time the RCDs fluorescence is restored and in an “on” state to illuminate the tumor cells, which achieved cancer imaging. The released Fe2+ reacts with H2O2 in the TME to form highly reactive hydroxyl radicals (•OH) by Fenton reaction, which achieves the chemodynamic therapy of tumors. Thus, efficient synergistic chemodynamic‐photothermal dual mode therapy is achieved under fluorescence imaging guidance with TME response.