Latest ArticlesHistone H3K79 modifications are essential to regulate chromatin structure and gene transcription, but understanding of the molecular mechanisms is limited. Because H3K79 is at globular domain, short histone peptide cannot mimic H3K79 in chromatin. Instead, reconstituted nucleosome-based chemical tools are ideally used to investigate H3K79 modifications. In consequence, H3K79-modified histone H3 with additional chemical handles are required, but such synthesis is challenging and laborious. Here we report a facile semisynthesis method that enables multifunctional histone H3 readily available. H3K79-containing fragment is short for straight peptide synthesis that was later ligated to recombinant expressed H3 fragments for full-length product in large scale. As a result, nucleosomes with H3K79 modifications as well as photo-reactive group and affinity tag were obtained to investigate potential binding proteins. We believe this method that enhances synthetic accessibility of nucleosome probes will accelerate understanding of the underexplored H3K79 modifications.
Carbon dots (CDs), as a solid-state phosphor, have great potential for application in a new solid-state lighting device—laser diode (LD). For high efficiency LD devices, both high photoluminescence quantum yield (PLQY) and high photothermal stability of CDs are essential. Herein, yellow CDs@ZIF-8 composites with high structural stability were prepared by encapsulating CDs in zeolitic imidazolate framework-8 (ZIF-8) through electrostatic adsorption between CDs and ZIF-8, in which CDs with amino groups on the surface were used as luminescent feeders and ZIF-8 was used as a protective layer matrix. The as-prepared CDs@ZIF-8 not only possess a high PLQY of up to 81.17%, but also maintain a high fluorescence intensity of 100% and 80% under long-term illumination (60 min) and high temperature (478 K), respectively. The hydrogen bonding between CDs and ZIF-8 in the encapsulated structure can enhance the degree of electron cloud delocalization, which can improve the PLQY of CDs@ZIF-8. Meanwhile, CDs@ZIF-8 has high photothermal stability due to the binding effect of ZIF-8 on CDs and high thermal stability of ZIF-8. The white LD device, fabricated from CDs@ZIF-8 as a phosphor in combination with 450 nm blue LD, has a color coordinate of (0.37, 0.33), a color temperature of 3762 K, and a high color rendering index of 86. This study provides a new strategy for the construction of solid-state phosphors with high PLQY and high photothermal performance.
Photodynamic therapy (PDT) has garnered significant attention as a promising approach to cancer therapy, harnessing the combined benefits of localized light treatment and the accompanying host immune response. In this study, we engineered an immuno-enhanced PDT nanoplatform, denoted as HM@p-MOF (hybrid membrane@porphyrin-metal organic framework). The core porphyrin-MOF was cloaked with a hybrid membrane derived from B16F10 cancer cells and NK cells, resulting in enhanced stability. In both in vitro and in vivo experiments, our finding demonstrated that the hybrid membrane conferred dual targeting capabilities to the nanoplatform, leveraging the unique properties of the B16F10 membrane and NK membrane to augment immunogenic cell death (ICD) induced by photodynamic effects. Additionally, in conjunction with the immunomodulatory functions of the NK cell membrane, we observed an expansion of in situ immune infiltration leading to a systemic immune response. The HM@p-MOF nanoplatform exhibited the capacity to not only inhibit the growth of mouse melanoma but also suppress metastasis. This innovative HM@p-MOF nanoplatform present a viable strategy to enhance phototherapeutic efficacy for both localized and metastatic tumors. It provides a direction for the fabrication of biomimetic nanomedicines possessing immuno-modulatory function.
The combination of interface engineering and defect engineering is a promising strategy for developing new semiconducting surface-enhanced Raman scattering (SERS) substrate. Herein, an organic/inorganic hybrid g-C3N4/TiO2-X heterojunction with synchronous generation of strong interface effect and abundant surface oxygen vacancy (OV) defect was prepared by a simple sol-hydrothermal procedure with a help of urea. Due to the improved substrate-to-molecule charge transfer (CT) from joint contribution of high-efficiency carrier separation induced by strong interface coupling effect and multiple CT paths derived from abundant surface OV, g-C3N4/TiO2-X substrate exhibits greatly enhanced SERS effect for non-resonant 4-mercaptobenzoic acid (4-MBA) probe. The enhancement factor of g-C3N4/TiO2-X substrate for 4-MBA is as high as 5.57 × 106, and the substrate exhibits ultra-high stability and excellent spectral reproducibility. More meaningfully, the developed g-C3N4/TiO2-X heterojunction can be used to execute an ultrasensitive detection for antibiotic residues in real water system, even comprehensive evaluation of multi-component residues.
Solar-driven H2O2 production and emerging organic pollutants (EOPs) elimination are of great significance from the perspective of environmental sustainability. The efficiency of the photocatalytic reaction system is the key challenge to be addressed. In this work, the strategy of constructing surface ionic local polarization centers to enhance the exciton dissociation of the polymeric photocatalytic is demonstrated. Selected bipyridinium cation (TMAP) is complexed on a K+-incorporated carbon nitride (CNK) framework, and the combination of local polarization centers both on the surface (bipyridinium cation) and bulk (K+ cation) contributes to a superior photocatalytic H2O2 production performance, affording a remarkable H2O2 generation rate of 46.8 µmol h−1 mg−1 and a high apparent quantum yield (AQY) value of 77.5% under irradiation of 405 nm photons. As substantiated experimentally by steady state/transient spectroscopy techniques, the surface local polarization centers increase the population of the long-lived trapped electrons, and thereby promote the interfacial charge transfer process for chemical conversion reaction. The strategy is potentially applicable to the design of a wide range of efficient solar-to-chemical conversion systems.
Monosescinol A (1), the first example of sesquiterpene–polycyclic polyprenylated acylphloroglucinol (PPAP) adduct, which represented a new subclass of PPAP-type natural products, along with two new congeners with normal spiro 6/6/5 tricyclic architecture, were isolated from Hypericum longistylum. Monosescinol A possessed an unprecedented 6/5/5/6/6 pentacyclic carbon skeleton that might be assembled from the 6/6/5 carbon skeleton, via the splitting decomposition of C-3/C-14, and the attack from the C-3 in the PPAP core to C-28 in sesquiterpene section. In addition, we have firstly confirmed that 24R configuration was existed in sec–Bu containing PPAPs by single crystal diffraction data analysis of monosescinol B (2), that might provide an enlightenment in the configurational determination of sec–Bu containing PPAPs. Significantly, further pharmacological research has found that compound 1 exhibited remarkable pharmacological effects against acute myeloid leukemia (AML) cell lines, with direct inhibition of mitochondrial complex Ⅴ and an increase in mitochondrial membrane potential, and led to an induction of oxidative stress, endogenous inflammation, and apoptosis of AML cells.
Sodium percarbonate (Na2CO3·1.5H2O2, SPC) has been extensively employed as a solid substitute of H2O2 for Fenton process in water treatment, because of its high stability during the production, transport, storage and usage. In addition, SPC can be applied in a wider range of work pH, it is also applied as a buffer in Fenton reaction for preventing a drop in pH. Herein, we have synthesized basic copper molybdate (BCM) nanoblocks with the molecular formula of Cu3(MoO4)2(OH)2 as an efficient and heterogeneous catalyst for antibiotics degradation via percarbonate activation. First, fully physical characterizations confirmed BCM nanocomposite exhibited a structure of nanoblocks. We also found that BCM/SPC system could work in a much wider pH range, compared with H2O2. Then, BCM/SPC system presented a good anti-interference ability for natural organic matter in OTC degradation. EPR results and Quenching tests confirmed that the co-presence of ·CO3−, ·O2−, 1O2 and ·OH in BCM/SPC system.
Clinical phototheranostic agents suffer from low absorption in near-infrared (NIR) region, decreasing singlet oxygen quantum yield (1O2 QY) caused by aggregation in water, and low photothermal conversion efficiency (PCE), all of which are factors weakening their phototheranostic efficacy. Herein, we designed and synthesized a donor-acceptor-donor (D-A-D) structured boron-dipyrromethene derivative (B-2TPA) which exhibited NIR absorption and fluorescence. After being encapsulated in amphiphilic distearoyl phosphoethanolamine polyethyleneglycol 2000 (DSPE-PEG-2000), the water-soluble B-2TPA nanoparticles (NPs) had increasing 1O2 QY (6.7%) due to the intermolecular aggregation-induced decrease in the energy gap between singlet and triplet excited states. Moreover, the quenched fluorescence and stable twisted intramolecular charge transfer in aggregates further increased the PCE of B-2TPA NPs to 60.1%. In vitro and in vivo studies confirmed that B-2TPA NPs could be used in NIR fluorescence and photoacoustic imaging-guided synergistic photodynamic and photothermal therapy in tumor treatment.
Spin-orbit, charge-transfer intersystem crossing (SOCT-ISC) can directly overcome the disadvantages of the traditional heavy-atom effect and improve the generation efficiency of reactive oxygen species (ROS). Since orthogonal molecular orbitals of donor-acceptor (D-A) pairs favor the SOCT-ISC transition, herein aza-borondipyrromethenes (aza-BODIPYs) with 1,7-di-anthracyl groups (An-azaBDP) was successfully prepared, owing to steric hindrance to produce a big dihedral angle between the two molecular orbital (MO) planes. Moreover, according to density functional theory (DFT) and time-dependent density functional theory (TDDFT), the energy difference between the S1-T1 orbitals of An-azaBDP is small and more inclined towards ISC. An-azaBDP can effectively generate singlet oxygen under light irradiation. An-azaBDP with light irradiation can induce apoptosis in SW620 cells, and can serve as a potential candidate for the treatment of cancer cells and tumors.
The occurrence of acquired resistance to cisplatin (DDP) that induces the toxic drug effects has always been a huge challenge and urgently needs to be resolved in the cancer treatment. The combination of anticancer drugs with different mechanisms can remarkably improve the chemotherapeutic efficiency. Given that glutathione (GSH) plays as the driving factors in the resistance of DDP, here we have firstly proposed a “three birds, one stone” based nanoplatform to achieve triple synergetic effects simultaneously addressing DDP resistance in non-small cell lung cancer (NSCLC). Specifically, we initially designed and synthesized a DDP prodrug [Pt(Ⅳ)] bridged silsesquioxane precursor (Pt-Si). Then Pt-Si and bis[3-(triethoxysilyl)propyl]diselenide (BTESePD) were integrated into the framework of mesoporous organosilica nanoparticles (MONs) to obtain a nanocarrier MONPt/Se. After loading with norcantharidin (NCTD) and modifying with the aptamer AS1411 based G-quadruplex (Apt), the Apt@NCTD@MONPt/Se exhibit impressive tumor homing capability. Once being endocytosed, (Ⅰ) the diselenide and -O-Pt(Ⅳ)-O- rich scaffold can be reduced by the excessive GSH, followed by (Ⅱ) breaking the redox homeostasis via GSH depletion and precise release of the DDP. Next, the encapsulated NCTD is also released along with the degradation of the nanocarriers thereby (Ⅲ) achieving the GSH depletion and synergistic anti-tumor effect of NCTD and DDP. Taken together, we believe this “one stone, three birds” strategy may be a promising paradigm to conquer drug resistance for clinical care.