Latest ArticlesListeria monocytogenes (LM) is a dangerous foodborne pathogen for humans. One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone (3H2B) gas. In this study, the synthesis of 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTMS) functionalized hierarchical hollow TiO2 nanospheres was achieved via precise controlling of solvothermal reaction temperature and post-grafting route. The sensors based on as-prepared materials exhibited excellent sensitivity (480 Hz@50 ppm), low detection limit (100 ppb), and outstanding selectivity. Moreover, the evaluation of LM with high sensitivity and specificity was achieved using the sensors. Such stable three-dimensional spheres, whose distinctive hierarchical and hollow nanostructure simultaneously improved both sensitivity and response/recovery speed dramatically, were spontaneously assembled by nanosheets. Meanwhile, the moderate loadings of AAPTMS significantly improved the selectivity of sensors. Then, the gas-sensing mechanism was explored by utilizing thermodynamic investigation, Gaussian 16 software, and in situ diffuse reflectance infrared transform spectroscopy, illustrating the weak chemisorption between the -NH- group and 3H2B molecules. These portable sensors are promising for real-time assessment of LM at room temperature, which will make a magnificent contribution to food safety.
Photodynamic therapy (PDT) has emerged as a promising approach for tumor treatment due to its non-invasiveness and high selectivity. However, the off-target activation of phototoxicity and the limited availability of tumor-specific biomarkers pose challenges for effective PDT. Here, we present the development of a novel ratiometric near-infrared-Ⅱ (NIR-Ⅱ) fluorescent organic nanoprobe, BTz-IC@IR1061, which responds specifically to hypochlorite (HClO) within tumors. This nanoprobe allows ratiometric fluorescence imaging to monitor and guide activated tumor PDT. BTz-IC@IR1061 nanoparticles were synthesized by codoping the small molecule dye BTz-IC, which generates reactive oxygen species (ROS), with the commercial dye IR1061. The presence of HClO selectively activates the fluorescence and photodynamic properties of BTz-IC while destroying IR1061, enabling controlled release of ROS for tumor therapy. We demonstrated the high selectivity of the nanoprobe for HClO, as well as its excellent photostability, photoacoustic imaging capability, and photothermal effects. Furthermore, in vivo studies revealed effective tumor targeting and remarkable tumor growth inhibition through tumor-activated PDT. Our findings highlight the potential of BTz-IC@IR1061 as a promising tool for tumor-specific PDT, providing new opportunities for precise and controlled cancer therapy.
Chemical modification of native peptides and proteins is a versatile strategy to facilitate late-stage diversification for functional studies. Among the proteogenic amino acids, lysine is extensively involved in post-translational modifications and the binding of ligands to target proteins, making its selective modification attractive. However, lysine’s high natural abundance and solvent accessibility, as well as its relatively low reactivity to cysteine, necessitate addressing chemoselectivity and regioselectivity for the Lys modification of native proteins. Although Lys chemoselective modification methods have been well developed, achieving site-selective modification of a specific Lys residue remains a great challenge. In this review, we discussed the challenges of Lys selective modification, presented recent examples of Lys chemoselective modification, and summarized the currently known methods and strategies for Lys site-selective modification. We also included an outlook on potential solutions for Lys site-selective labeling and its potential applications in chemical biology and drug development.
Efficient electrocatalysts for oxygen reduction reaction (ORR) show significant importance for advancing the performance and affordability of proton exchange membrane fuel cells and other energy conversion devices. Herein, PtCo3 nanoalloys dispersed on a carbon black support, were prepared using ultrafast Joule heating method. By tuning the heating modes, such as high-temperature shock and heating for 2 s, two kinds of PtCo3 nanoalloys with varying crystallinities were obtained, referred to as PtCo3HTS (average size of 5.4 nm) and PtCo3HT-2 s (average size of 6.4 nm), respectively. Impressively, PtCo3HTS exhibited superior electrocatalytic ORR activity and stability (E1/2 = 0.897 V vs. RHE and 36 mV negative shift after 50, 000 cycles), outperforming PtCo3HT-2 s (E1/2 = 0.872 V and 16.2 mV negative shift), as well as the commercial Pt/C (20 wt%) catalyst (E1/2 = 0.847 V and 21.0 mV negative shift). The enhanced ORR performance of PtCo3HTS may be attributed to its low crystallinity, which results in an active local electronic structure and chemical state, as confirmed by X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) analyses. The ultrafast Joule heating method showed great potential for crystallinity engineering, offering a promising pathway to revolutionize the manufacturing of cost-effective and environmentally friendly catalysts for clean energy applications.
A computer-assisted chemical investigation of an intriguing photoreaction of norditerpenoids (3‒7) has been first reported, leading to not only their biomimetic conversion, but also the generation of several new products with uncommon 4,14-dioxabicyclo[10.2.1]pentadecane scaffold (8, 9, 12‒14). In bioassay, compounds 10 and 15 exhibited significant stimulation of GLP-1 secretion. This study has given an insight for the application of computational methods on the late-stage skeleton transformation of complex natural products towards new bioactive compounds.
D-D'-A type aza-borondipyrromethenes (aza-BODIPYs) were prepared by Suzuki cross-coupling reaction. Photothermal conversion efficiency of self-assemble aza-BODIPY-based nanoparticles (DA-azaBDP-NPs) with NIR-II emission (λem = 1065 nm) was 37.2% under near infrared (NIR) irradiation, and the outstanding cytotoxicity was triggered by coexistence of DA-azaBDP-NPs and the NIR irradiation, with the decrease of glioblastoma migration and the inhibition of glioblastoma proliferation. DA-azaBDP-NPs could promote glioblastoma autophagy and accelerate the process of cell death. The photothermal therapy (PTT) of DA-azaBDP-NPs can effectively induce glioblastoma death by apoptosis under the NIR irradiation, which is highly promising to be applied in vivo experiments of brain.
Carbon dots (CDs) are an emerging class of zero-dimensional carbon nano optical materials that are as promising candidates for various applications. Through the exploration of scientific researchers, the optical band gap of CDs has been continuously regulated and red-shifted from the initial blue-violet light to longer wavelengths. In recent years, CDs with near-infrared (NIR) absorption/emission have been gradually reported. Because NIR light has deeper penetration and lower scattering and is invisible to the human eye, it has great application prospects in the fields of biological imaging and treatment, information encryption, optical communications, etc. Although there are a few reviews on deep red to NIR CDs, they only focus on the single biomedical direction. There is still a lack of comprehensive reviews focusing on NIR (≥700 nm) absorption and luminescent CDs and their multifunctional applications. Based on our research group’s findings on NIR CDs, this review summarizes recent advancements in their preparation strategies and applications, points out the current shortcomings and challenges, and anticipates future development trajectories.
Generally, gaining fundamental insights into chain processes during the combustion of flame-retardant polymers relies on the qualitative and quantitative characterization of key chain carriers. However, polymer combustion processes based on conventional solid-fuel combustion strategies, due to the high coupling of pyrolysis, combustion, soot formation and oxidation, exhibit relatively high complexity and poor flame stability, and lead to a huge obstacle to the use of optical diagnostics. Herein, a spatial-confinement combustion strategy, which can produce a special staged flame with multi-jets secondary wave, is devised to provide a highly decoupled combustion environment. Glowing soot particles are therefore decoupled from main chemiluminescence region and confined to the flame tip to provide a well-controlled, optical-thin test environment for combustion diagnostic. Based on this strategy, a multi-nozzle-separation (MNS) burner is designed and fabricated, and the combustion processes associated with four model compounds, PVC, PS, PP/TBBA blends and PP/RP blends are investigated by spontaneous spectral diagnosis, and the chemiluminescence fingerprint of key diatomic/triatomic intermediates (such as OH, CH, C2, ClO, Br2, and PHO) are clearly observed. This encouraging result means that the strategy of spatial-confinement combustion we proposed shows promising prospect in many subjects associated with combustion chain regulation, such as efficient design of flame retardants.
Room-temperature phosphorescence (RTP) materials exhibiting long emission lifetimes have gained increasing attention owing to their potential applications in encryption, anti-counterfeiting, and sensing. However, most polymers exhibit a short RTP lifetime (<1 s) because of their unstable triplet excitons. Herein, a new strategy of polymer chain stabilized phosphorescence (PCSP), which yields a new kind of RTP polymers with an ultralong lifetime and a sensitive oxygen response, has been reported. The rigid polymer chains of poly(methyl mathacrylate) (PMMA) immobilize the emitter molecules through multiple interactions between them, giving rise to efficient RTP. Meanwhile, the loosely-packed amorphous polymer chains allow oxygen to diffuse inside, endowing the doped polymers with oxygen sensitivity. Flexible and transparent polymer films exhibited an impressive ultralong RTP lifetime of 2.57 s at room temperature in vacuum, which was among the best performance of PMMA. Intriguingly, their RTP was rapidly quenched in the presence of oxygen. Furthermore, RTP microparticles with a diameter of 1.63 µm were synthesized using in situ dispersion polymerization technique. Finally, oxygen sensors for quick, visual, and quantitative oxygen detection were developed based on the RTP microparticles through phosphorescence lifetime and image analysis. With distinctive advantages such as an ultralong lifetime, oxygen sensitivity, ease of fabrication, and cost-effectiveness, PCSP opens a new avenue to sensitive materials for oxygen detection.
Triphenylamine (TPA) is the most promising donor fragment for the construction of long-wavelength thermally activated delayed fluorescence (TADF) emitters owing to its suitable dihedral angle that could enhance radiative decay to compete with the serious non-radiative decay. However, the moderate electron-donating capacity of TPA seriously limits the selection of acceptor for constructing long-wavelength TADF emitters with narrow bandgaps. To address this issue, in this work, the peripheral benzene of TPA was replaced with 1,4-benzodioxane and anisole to obtain two new electron-donating units N-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-N-phenyl-2,3-dihydrobenzo[b][1,4]dioxin-6-amine (TPADBO, −5.02 eV) and 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline (TPAMO, −5.00 eV), which possess much shallower highest occupied molecule orbital (HOMO) energy levels than the prototype TPA (−5.33 eV). Based on TPA and the modified TPA donor fragments, three TADF emitters were designed and synthesized, namely Py-TPA, Py-TPADBO and Py-TPAMO, with the same acceptor fragment 12-(2,6-diisopropylphenyl)pyrido[2′,3′:5,6]pyrazino[2,3-f][1,10]phenanthroline (Py). Among them, Py-TPAMO exhibits the highest photoluminescence quantum yield of 78.4% and the smallest singlet-triplet energy gap, which is because the introduction of anisole does not cause significant molecule deformation for the excited Py-TPAMO. And Py-TPAMO-based OLEDs successfully realize a maximum external quantum efficiency of 25.5% with the emission peak at 605 nm. This work provides a series of candidate of donor fragments for the development of efficient long-wavelength TADF emitters.
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