Thiele's Fluorocarbons: Stable Diradicaloids with Efficient Visible-to-Near-Infrared Fluorescence from a Zwitterionic Excited State.

Thiele's hydrocarbon was the first synthesized diradicaloid in the search for stable open-shell structures, but it remains sensitive to oxygen and light. We here report the synthesis of Thiele's fluorocarbon (TFC) and its derivatives exhibiting exceptional thermal, oxidative, and photostability. TFCs have remarkable luminescent properties with yellow to NIR fluorescence and up to 100% quantum yields. X-ray crystallography and ESR spectroscopy confirm their closed-shell quinoidal ground state. As expected from their symmetric nonpolar structure, the TFCs' absorption spectra show no solvent effect, but their emission reveals an extraordinarily large Stokes shift which increases with solvent polarity (from 0.9 eV in cyclohexane to 1.5 eV in acetonitrile). We show that this behavior is a result of sudden polarization, leading to a zwitterionic excited state.

Development of a TNF-α-mediated Trojan Horse for bacteria-based cancer therapy.

Tumor necrosis factor α (TNF-α) is upregulated in a chronic inflammatory environment, including tumors, and has been recognized as a pro-tumor factor in many cancers. Applying the traditional TNF-α antibodies that neutralize TNF-α activity, however, only exerts modest anti-tumor efficacy in clinical studies. Here, we develop an innovative approach to target TNF-α that is distinct from the neutralization mechanism. We employed phage display and yeast display to select non-neutralizing antibodies that can piggyback on TNF-α and co-internalize into cells through receptor ligation. When conjugating with toxins, the antibody exhibited cytotoxicity to cancer cells in a TNF-α-dependent manner. We further implemented the immunotoxin to an E. coli vehicle specially engineered for a high secretion level. In a syngeneic murine melanoma model, the bacteria stimulated TNF-α expression that synergized with the secreted immunotoxin and greatly inhibited tumor growth. The treatment also dramatically remodeled the tumor microenvironment in favor of several anti-tumor immune cells, including N1 neutrophils, M1 macrophages, and activated CD4+ and CD8+ lymphocytes. We anticipate that our new piggyback strategy is generalizable to targeting other soluble ligands and/or conjugates with different drugs for managing a diverse set of diseases.

RetroGNN: Fast Estimation of Synthesizability for Virtual Screening and De Novo Design by Learning from Slow Retrosynthesis Software.

De novo molecule design algorithms often result in chemically unfeasible or synthetically inaccessible molecules. A natural idea to mitigate this problem is to bias these algorithms toward more easily synthesizable molecules using a proxy score for synthetic accessibility. However, using currently available proxies can still result in highly unrealistic compounds. Here, we propose a novel approach, RetroGNN, to estimate synthesizability. First, we search for routes using synthesis planning software for a large number of random molecules. This information is then used to train a graph neural network to predict the outcome of the synthesis planner given the target molecule, in which the regression task can be used as a synthesizability scorer. We highlight how RetroGNN can be used in generative molecule-discovery pipelines together with other scoring functions. We evaluate our approach on several QSAR-based molecule design benchmarks, for which we find synthesizable molecules with state-of-the-art scores. Compared to the virtual screening of 5 million existing molecules from the ZINC database, using RetroGNNScore with a simple fragment-based de novo design algorithm finds molecules predicted to be more likely to possess the desired activity exponentially faster, while maintaining good druglike properties and being easier to synthesize. Importantly, our deep neural network can successfully filter out hard to synthesize molecules while achieving a 105 times speedup over using retrosynthesis planning software.

Assessment of indocyanine green tracer-guided lymphadenectomy in laparoscopic gastrectomy after neoadjuvant chemotherapy for locally advanced gastric cancer: results from a multicenter analysis based on propensity matching.

BACKGROUND: This study evaluated the safety, effectiveness, and feasibility of indocyanine green (ICG) tracing in guiding lymph-node (LN) dissection during laparoscopic D2 radical gastrectomy in patients with advanced gastric cancer (AGC) after neoadjuvant chemotherapy (NAC). METHOD: We retrospectively analyzed data on 313 patients with clinical stage of cT1-4N0-3M0 who underwent laparoscopic radical gastrectomy after NAC between February 2010 and October 2020 from two hospitals in China. Grouped according to whether ICG was injected. For the ICG group (n = 102) and non-ICG group (n = 211), 1:1 propensity matching analysis was used. RESULTS: After matching, there was no significant difference in the general clinical pathological data between the two groups (ICG vs. non-ICG: 94 vs. 94). The average number of total LN dissections was significantly higher in the ICG group and lower LN non-compliance rate than in the non-ICG group. Subgroup analysis showed that among patients with LN and tumor did not shrink after NAC, the number of LN dissections was significantly more and LN non-compliance rate was lower in the ICG group than in the non-ICG group. Intraoperative blood loss was significantly lesser in the ICG group than in the non-ICG group, while the recovery and complications of the two groups were similar. CONCLUSION: For patients with poor NAC outcomes, ICG tracing can increase the number of LN dissections during laparoscopic radical gastrectomy, reduce the rate of LN non-compliance, and reduce intraoperative bleeding. Patients with AGC should routinely undergo ICG-guided laparoscopic radical gastrectomy.

Combining Proximity Labeling and Cross-Linking Mass Spectrometry for Proteomic Dissection of Nuclear Envelope Interactome.

Proximity labeling (PL) and chemical cross-linking (XL) mass spectrometry are two powerful methods to dissect protein-protein interactions (PPIs) in cells. Although PL typically captures neighboring proteins within a range of 10-20 nm of a single bait protein, chemical XL defines direct protein-protein contacts within 1 nm in a systemic manner. Here, we develop a new method, named PL/XL-MS, to harness the advantages of both PL and XL. PL/XL-MS can enrich a subcellular compartment by PL and simultaneously identify PPIs of multiple proteins from XL data. We applied PL/XL-MS to dissect the human nuclear envelope interactome. PL/XL-MS successfully enriched the nuclear envelope proteins and identified most known inner nuclear membrane proteins. By searching the cross-linked peptides, we successfully observed 109 literature-curated PPIs of 14 nuclear envelope proteins. Based on the homoprotein XL data, we experimentally characterized a nuclear matrix protein, Matrin-3, and observed its preferential localization near the nuclear envelope. PL/XL-MS is a simple and general method for studying protein networks in a subproteome of interest.

Transformation between 2D and 3D Covalent Organic Frameworks via Reversible [2 + 2] Cycloaddition.

We report the first transformation between crystalline vinylene-linked two-dimensional (2D) polymers and crystalline cyclobutane-linked three-dimensional (3D) polymers. Specifically, absorption-edge irradiation of the 2D poly(arylenevinylene) covalent organic frameworks (COFs) results in topological [2 + 2] cycloaddition cross-linking of the π-stacked layers in 3D COFs. The reaction is reversible, and heating to 200 °C leads to a cycloreversion while retaining the COF crystallinity. The resulting difference in connectivity is manifested in the change of mechanical and electronic properties, including exfoliation, blue-shifted UV-vis absorption, altered luminescence, modified band structure, and different acid-doping behavior. The Li-impregnated 2D and 3D COFs show a significant room-temperature ion conductivity of 1.8 × 10-4 S/cm and 3.5 × 10-5 S/cm, respectively. Even higher room-temperature proton conductivity of 1.7 × 10-2 S/cm and 2.2 × 10-3 S/cm was found for H2SO4-treated 2D and 3D COFs, respectively.

A Two-Dimensional Poly(azatriangulene) Covalent Organic Framework with Semiconducting and Paramagnetic States.

The black crystalline (aza)triangulene-based covalent organic framework TANG-COF was synthesized from its trinitro-TANG precursor via a one-pot, two-step reaction involving Pd-catalyzed hydrogenation and polycondensation with an aromatic dialdehyde. High crystallinity and permanent porosity of the layered two-dimensional (2D) structure were established. The rigid, electron-rich trioxaazatriangulene (TANG) building block enables strong π-electron interactions manifested in broad absorptions across the visible and NIR regions (Eg ≈ 1.2 eV). The high HOMO energy of TANG-COF (-4.8 eV) enables facile p doping, resulting in electrical conductivity of up to 10-2 S/cm and room-temperature paramagnetic behavior with a spin concentration of ∼10%. DFT calculations reveal dispersion of the highest occupied band both within the 2D polymer layers (0.28 eV) and along their π-stacked direction (0.95 eV).

Understanding the Photovoltaic Behavior of A-D-A Molecular Semiconductors through a Permutation of End Groups.

The facile synthesis of a series of benzodithiophene (BDT)- and indacenodithiophene (IDT)-based A-D-A oligomers with different end groups is reported, and their properties are studied by optical spectroscopy, electrochemistry, and density functional theory calculations. The permutation of central and terminal units tunes the optoelectronic properties and photovoltaic device characteristics in a predictable way, aiding in the rational design of small molecule semiconducting materials. Among the three rhodanine-derived terminal groups, N-alkylthiazolonethione revealed the strongest electron-withdrawing character, resulting in the lowest band gap, the highest stability, and the best photovoltaic device performance. The crystallographic analysis of two IDT derivatives yielded a highly unusual three-dimensional packing of the conjugated backbone, which is likely responsible for the remarkable photovoltaic performance of such A-D-A semiconductors.

A Pure-Red Doublet Emission with 90 % Quantum Yield: Stable, Colorless, Iodinated Triphenylmethane Solid.

Red luminescence is found in off-white tris(iodoperchlorophenyl)methane (3I-PTMH ) crystals which is characterized by a high photoluminescence quantum yield (PLQY 91 %) and color purity (CIE coordinates 0.66, 0.34). The emission originates from the doublet excited state of the neutral radical 3I-PTMR , which is spontaneously formed and becomes embedded in the 3I-PTMH matrix. The radical defect can also be deliberately introduced into 3I-PTMH crystals which maintain a high PLQY with up to 4 % radical concentration. The immobilized iodinated radical demonstrates excellent photostability (estimated half-life >1 year under continuous irradiation) and intriguing luminescent lifetime (69 ns). TD-DFT calculations demonstrate that electron-donating iodine atoms accelerate the radiative transition while the rigid halogen-bonded matrix suppresses the nonradiative decay.

Strong Enhancement of π-Electron Donor/Acceptor Ability by Complementary DD/AA Hydrogen Bonding.

π-Conjugated organic materials possess a wide range of tunable optoelectronic properties which are dictated by their molecular structure and supramolecular arrangement. While many efforts have been put into tuning the molecular structure to achieve the desired properties, rational supramolecular control remains a challenge. Here, we report a novel series of supramolecular materials formed by the co-assembly of weak π-electron donor (indolo[2,3-a]carbazole) and acceptor (aromatic o-quinones) molecules via complementary hydrogen bonding. The resulting polarization creates a drastic perturbation of the molecular energy levels, causing strong charge transfer in the weak donor-acceptor pairs. This leads to a significant lowering (up to 1.5 eV) of the band gaps, intense absorption in the near-IR region, very short π-stacking distances (≥3.15 Å), and strong ESR signals in the co-crystals. By varying the strength of the acceptor, the characteristics of the complexes can be tuned between intrinsic, gate-, or light-induced semiconductivity with a p-type or ambipolar transport mechanism.

2D Poly(arylene vinylene) Covalent Organic Frameworks via Aldol Condensation of Trimethyltriazine.

Designing structural order in electronically active organic solids remains a great challenge in the field of materials chemistry. Now, 2D poly(arylene vinylene)s prepared as highly crystalline covalent organic frameworks (COFs) by base-catalyzed aldol condensation of trimethyltriazine with aromatic dialdehydes are reported. The synthesized polymers are highly emissive (quantum yield of up to 50 %), as commonly observed in their 1D analogues poly(phenylene vinylene)s. The inherent well-defined porosity (surface area ca. 1000 m2 g-1 , pore diameter ca. 11 Šfor the terephthaldehyde derived COF-1) and 2D structure of these COFs also present a new set of properties and are likely responsible for the emission color, which is sensitive to the environment. COF-1 is highly hydrophilic and reveals a dramatic macroscopic structural reorganization that has not been previously observed in framework materials.

Combinatorial leaky probiotic for anticancer immunopotentiation and tumor eradication.

Combination therapies present a compelling therapeutic regimen against the immunosuppressive and heterogeneous microenvironment of solid tumors. However, incorporating separate therapeutic modalities in regimen designs can be encumbered by complex logistical, manufacturing, and pharmacokinetic considerations. Herein, we demonstrate a single-vector combinational anticancer therapy using an lpp gene knockout leaky probiotic for simultaneous secretion of immunotherapeutic and oncolytic effector molecules. Through fusion protein design and vector optimization, a Nissle1917 (EcN) bacteria vector is engineered to secrete Neoleukin-2/15 (Neo-2/15) cytokine-functionalized anti-PDL1 nanobody (aPDL1-Neo2/15) and anti-mesothelin-functionalized hemolysin E (HlyE-aMSLN). The multifunctional leaky probiotic enables synchronous immune activation and tumor-targeted cytolytic activity for effective tumor suppression, elevation of tumor immune cell infiltration, and establishment of anticancer immunological memory. lpp gene knockout is further shown to improve probiotic tolerability and intravenous applicability, offering a therapeutically viable approach for combination regimen development.

Efficient room-temperature phosphorescence of covalent organic frameworks through covalent halogen doping.

Organic room-temperature phosphorescence, a spin-forbidden radiative process, has emerged as an interesting but rare phenomenon with multiple potential applications in optoelectronic devices, biosensing and anticounterfeiting. Covalent organic frameworks (COFs) with accessible nanoscale porosity and precisely engineered topology can offer unique benefits in the design of phosphorescent materials, but these are presently unexplored. Here, we report an approach of covalent doping, whereby a COF is synthesized by copolymerization of halogenated and unsubstituted phenyldiboronic acids, allowing for random distribution of functionalized units at varying ratios, yielding highly phosphorescent COFs. Such controlled halogen doping enhances the intersystem crossing while minimizing triplet-triplet annihilation by diluting the phosphors. The rigidity of the COF suppresses vibrational relaxation and allows a high phosphorescence quantum yield (ΦPhos ≤ 29%) at room temperature. The permanent porosity of the COFs and the combination of the singlet and triplet emitting channels enable a highly efficient COF-based oxygen sensor, with an ultra-wide dynamic detection range (~103-10-5 torr of partial oxygen pressure).

Silver nanoparticle enhanced metal-organic matrix with interface-engineering for efficient photocatalytic hydrogen evolution.

Integrating plasmonic nanoparticles into the photoactive metal-organic matrix is highly desirable due to the plasmonic near field enhancement, complementary light absorption, and accelerated separation of photogenerated charge carriers at the junction interface. The construction of a well-defined, intimate interface is vital for efficient charge carrier separation, however, it remains a challenge in synthesis. Here we synthesize a junction bearing intimate interface, composed of plasmonic Ag nanoparticles and matrix with silver node via a facile one-step approach. The plasmonic effect of Ag nanoparticles on the matrix is visualized through electron energy loss mapping. Moreover, charge carrier transfer from the plasmonic nanoparticles to the matrix is verified through ultrafast transient absorption spectroscopy and in-situ photoelectron spectroscopy. The system delivers highly efficient visible-light photocatalytic H2 generation, surpassing most reported metal-organic framework-based photocatalytic systems. This work sheds light on effective electronic and energy bridging between plasmonic nanoparticles and organic semiconductors.

Bidirectional Phase Transformation of Supramolecular Networks Using Two Molecular Signals.

Reversible control of molecular self-assembly is omnipresent in adaptive biological systems, yet its realization in artificial systems remains a major challenge. Using scanning tunneling microscopy and density functional theory calculations, we show that a 2D supramolecular network formed by terthienobenzenetricarboxylic acid (TTBTA) can undergo a reversible structural transition between a porous and dense phase in response to different molecular signals (trimethyltripyrazolotriazine (TMTPT) and C60). TMTPT molecules can induce a phase transition from the TTBTA honeycomb to the dense phase, whereas a reverse transition can be triggered by introducing C60 molecules. This response stems from the selective association between signal molecules and TTBTA polymorphs. The successful realization of reversible molecular transformation represents important progress in controlling supramolecular surface nanostructures and could be potentially applicable in various areas of nanotechnology, including phase control, molecular sensing, and "smart" switchable surfaces.

Development and verification of the glycolysis-associated and immune-related prognosis signature for hepatocellular carcinoma.

Background: Hepatocellular carcinoma (HCC) refers to the malignant tumor associated with a high mortality rate. This work focused on identifying a robust tumor glycolysis-immune-related gene signature to facilitate the prognosis prediction of HCC cases. Methods: This work adopted t-SNE algorithms for predicting glycolysis status in accordance with The Cancer Genome Atlas (TCGA)-derived cohort transcriptome profiles. In addition, the Cox regression model was utilized together with LASSO to identify prognosis-related genes (PRGs). In addition, the results were externally validated with the International Cancer Genome Consortium (ICGC) cohort. Results: Accordingly, the glycolysis-immune-related gene signature, which consisted of seven genes, PSRC1, CHORDC1, KPNA2, CDCA8, G6PD, NEIL3, and EZH2, was constructed based on TCGA-HCC patients. Under a range of circumstances, low-risk patients had extended overall survival (OS) compared with high-risk patients. Additionally, the developed gene signature acted as the independent factor, which was significantly associated with clinical stage, grade, portal vein invasion, and intrahepatic vein invasion among HCC cases. In addition, as revealed by the receiver operating characteristic (ROC) curve, the model showed high efficiency. Moreover, the different glycolysis and immune statuses between the two groups were further revealed by functional analysis. Conclusion: Our as-constructed prognosis prediction model contributes to HCC risk stratification.

Phase-enabled metal-organic framework homojunction for highly selective CO2 photoreduction.

Conversion of clean solar energy to chemical fuels is one of the promising and up-and-coming applications of metal-organic frameworks. However, fast recombination of photogenerated charge carriers in these frameworks remains the most significant limitation for their photocatalytic application. Although the construction of homojunctions is a promising solution, it remains very challenging to synthesize them. Herein, we report a well-defined hierarchical homojunction based on metal-organic frameworks via a facile one-pot synthesis route directed by hollow transition metal nanoparticles. The homojunction is enabled by two concentric stacked nanoplates with slightly different crystal phases. The enhanced charge separation in the homojunction was visualized by in-situ surface photovoltage microscopy. Moreover, the as-prepared nanostacks displayed a visible-light-driven carbon dioxide reduction with very high carbon monooxide selectivity, and excellent stability. Our work provides a powerful platform to synthesize capable metal-organic framework complexes and sheds light on the hierarchical structure-function relationships of metal-organic frameworks.

Morphological and optoelectronic characteristics of nanocomposites comprising graphene nanosheets and poly(3-hexylthiophene).

P3HT/graphene nanocomposite was prepared via in-situ reduction of exfoliated graphite oxide in the P3HT polymer matrix, where the exfoliated graphite oxide was formed beforehand via the oxidation of graphite via the Hummers method. The oxidation reaction not only imparts functional groups, such as C=O, C-OH, and C-O-C, to graphite but also causes exfoliation of the resulting graphite oxide. The functional groups render graphite oxide an additional, lower thermal degradation temperature (T(d)) and the exfoliation shifts the XRD pattern towards a much smaller angle. The oxidation of graphite into graphite oxide creates a pleated flaking morphology for graphite oxide as opposed to that of graphite. UV/Vis and photoluminescence (PL) spectra of P3HT/graphene nanocomposite indicate that the existence of graphene does not alter the UV/Vis and PL excitation characteristics of P3HT, and the P3HT/graphene composite has higher electron mobility, a smaller band gap and higher conductivity than the pristine P3HT.

Poly(9,9-dioctylfluorene-alt-thiophene)/graphene nanocomposite: effects of graphene on optoelectronic characteristics.

Nanocomposite comprising Poly(9,9-dioctylfluorene-alt-thiophene) (PDOFT) and graphene sheets was synthesized for the purpose of investigating its enhanced optoelectronic performance caused by the graphene. UV/Vis and photoluminescence spectra of PDOFT/graphene nanocomposite show that the existence of graphene does not alter the optical characteristics wavelength of PDOFT, and both solution samples and thin films emit green light. Meanwhile, the insignificant change in PL quantum efficiency indicates that graphene does not have significant effects on the transfer of excitation energy, the occurrence of self-quenching and the formation of excimer. However, the electric conductivity increases with an increase in the amount of graphene. The ionization potential(HOMO) and the electron affinity(LUMO) measured from the cyclic voltammetry lead to the determination of the optical band gap (Eg(chem)). When used to fabricate an optoelectronic device, the threshold voltage decreases with an increase in the graphene content until an excessive amount of graphene causes an unbalance on the electron and hole mobilities. The device fabricated with PDOFT/graphene with a 5% graphene content has a maximum luminescence of 5908 cd/m2 at a voltage of 9.5 V. The corresponding power efficiency at this maximum luminescence is 0.38 cd/A which is much higher than the device fabricated with pristine PDOFT. From the Admittance spectroscopy of the device, the electron mobility has been proved to increase with the graphene content.

Treatment of murine colitis by Saccharomyces boulardii secreting atrial natriuretic peptide.

Inflammatory bowel disease is a lifelong disorder that involves chronic inflammation in the small and large intestines. Current therapies, including aminosalicylates, corticosteroids, and anti-inflammatory biologics, can only alleviate the symptoms and often cause adverse effects with long-term usage. Engineered probiotics provide an alternative approach to treat inflammatory bowel disease in a self-renewable and local delivery fashion. In this work, we utilized a yeast probiotic Saccharomyces boulardii for this purpose. We developed a robust method to integrate recombinant genes into the Ty elements of S. boulardii. Stable yeast cell lines that secreted various anti-inflammatory proteins, including IL-10, TNFR1-ECD, alkaline phosphatase, and atrial natriuretic peptide (ANP), were successfully created and investigated for their efficacies to the DSS-induced colitis in mice through oral administration. While IL-10, TNFR1-ECD, and alkaline phosphatase did not show therapeutic effects, the ANP-secreting S. boulardii effectively ameliorated the mouse conditions as reflected by the improvements in body weight, disease activity index, and survival rate. A post-mortem examination revealed that the ANP-treated mice exhibited significant downregulations of TNF-α and IL-1ß and an upregulation of IL-6 in colon tissues. This observation is consistent with the previous reports showing that TNF-α and IL-1ß are responsible for initiating the pathogenesis, whereas IL-6 plays a protective role in colitis. Overall, we demonstrated that S. boulardii is a safe and robust vehicle for recombinant protein delivery in the gastrointestinal tract, and ANP is a potential anti-inflammatory drug for colitis treatment. KEY MESSAGES: Recombinant genes can be robustly integrated into the transposable elements of S. boulardii. Oral administration of S. boulardii secreting IL-10 or TNF-α inhibitor did not exert therapeutic effects for DSS-induced colitis in mice. Atrial natriuretic peptide-secreting S. boulardii effectively ameliorated the murine colitis as reflected by improved body weight, disease activity index, and survival rate. The ANP-treated mice exhibited decreased mRNA levels of TNF-α and IL-1ß and an increased mRNA level of IL-6 in colon tissues.