Latest ArticlesEfficient 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.
Designing advanced hydrogels with controlled mechanical properties, drug delivery manner and multifunctional properties will be beneficial for biomedical applications. However, the further development of hydrogel is limited due to its poor mechanical property and structural diversity. Hydrogels combined with polymeric micelles to obtain micelle-hydrogel composites have been designed for synergistic enhancement of each original properties. Incorporation polymeric micelles into hydrogel networks can not only enhance the mechanical property of hydrogel, but also expand the functionality of hydrogel. Recent advances in polymeric micelle-hydrogel composites are herein reviewed with a focus on three typical micelle incorporation methods. In this review, we will also highlight some emerging biomedical applications in developing micelle-hydrogel composite with multiple functionalities. In addition, further development and application prospects of the micelle-hydrogels composites have also been addressed.
Diseases associated with bacterial infection, especially those caused by gram-negative bacteria, have been posing a serious threat to human health. Photodynamic therapy based on aggregation-induced emission (AIE) photosensitizer have recently emerged and provided a promising approach for bacterial discrimination and efficient photodynamic antimicrobial applications. However, they often suffer from the shorter excitation wavelength and lower molar extinction coefficients in the visible region, severely limiting their further applications. Herein, three novel BF2-curcuminoid-based AIE photosensitizers, TBBC, TBC and TBBC-C8, have been rationally designed and successfully developed, in which OCH3- and OC8H17-substituted tetraphenylethene (TPE) groups serve as both electron donor (D) and AIE active moieties, BF2bdk group functions as electron acceptor (A), and styrene (or ethylene) group as π-bridge in this D-π-A-π-D system, respectively. As expected, these resulting BF2-curcuminoids presented solvent-dependent photophysical properties with large molar extinction coefficients in solutions and excellent AIE properties. Notably, TBBC showed an effective singlet oxygen generation efficiency thanks to the smaller singlet-triplet energy gap (ΔEST), and remarkable photostability under green light exposure at 530 nm (8.9 mW/cm2). More importantly, TBBC was demonstrated effectiveness in selective staining and photodynamic killing of Escherichia coli (E. coli) in vitro probably due to its optimal molecular size compared with TBC and TBBC-C8. Therefore, TBBC will have great potential as a novel AIE photosensitizer to apply in the discrimination and selective sterilization between Gram-positive and Gram-negative bacteria.
Acute lung injury (ALI) is a serious clinical condition with a high mortality rate. Oxidative stress and inflammatory responses play pivotal roles in the pathogenesis of ALI. ONOO− is a key mediator that exacerbates oxidative damage and microvascular permeability in ALI. Accurate detection of ONOO− would facilitate early diagnosis and intervention in ALI. Near-infrared fluorescence (NIRF) probes offer new solutions due to their sensitivity, depth of tissue penetration, and imaging capabilities. However, the developed ONOO− fluorescent probes face problems such as interference from other reactive oxygen species and easy intracellular diffusion. To address these issues, we introduced an innovative self-immobilizing NIRF probe, DCI2F-OTf, which was capable of monitoring ONOO− in vitro and in vivo. Importantly, leveraging the high reactivity of the methylene quinone (QM) intermediate, DCI2F-OTf was able to covalently label proteins in the presence of ONOO−, enabling in situ imaging. In mice models of ALI, DCI2F-OTf enabled real-time imaging of ONOO− levels and found that ONOO− was tightly correlated with the progression of ALI. Our findings demonstrated that DCI2F-OTf was a promising chemical tool for the detection of ONOO−, which could help to gain insight into the pathogenesis of ALI and monitor treatment efficacy.
Glioma is a severe malignant brain tumor marked by an exceedingly dire prognosis and elevated incidence of recurrence. The resilience of such tumors to chemotherapeutic agents, coupled with the formidable obstacle the blood-brain barrier (BBB) presents to most pharmacological interventions are major challenges in anti-glioma therapy. In an endeavor to surmount these impediments, we have synergized pH-sensitive nanoparticles carrying doxorubicin and apatinib to amplify the anti-neoplastic efficacy with cyclic arginine–glycine–aspartate acid (cRGD) modification. In this study, we found that the combination of doxorubicin (DOX) and apatinib (AP) showed a significant synergistic effect, achieved through cytotoxicity and induction of apoptosis, which might be due to the increased intracellular uptake of DOX following AP treatment. Besides, polycaprolactone-polyethylene glycol-cRGD (PCL-PEG-cRGD) drug carrier could cross the BBB by its targeting ability, and then deliver the drug to the glioma site via pH-responsive release, increasing the concentration of the drugs in the tumor. Meanwhile, DOX/AP-loaded PCL-PEG-cRGD nanoparticles effectively inhibited cell proliferation, enhanced glioma cell apoptosis, and retarded tumor growth in vivo. These results collectively identified DOX/AP-loaded PCL-PEG-cRGD nanoparticles as a promising therapeutic candidate for the treatment of glioma.
Insufficient endogenous H2O2 for generation of hydroxyl radicals (•OH) has strikingly compromised anti-tumor benefits of ferroptosis. Herein, we develop a H2O2 self-supplying nanoparticle based on a pH-responsive lipopeptide C18-pHis10. Inspired by the coordinate pattern of hemoglobin binding heme, Fe2+ and tetrakis(4-carboxyphenyl)porphyrin (TCPP) were delicately encapsulated by formation of coordination compounds with His. Ascorbgyl palmitate (AscP) was also incorporated into the nanoparticles for generation of H2O2 by reduction 1O2 produced from TCPP, meanwhile prevented Fe2+ from being oxidized. The protonation of pHis in acidic endo-lysosome induced the breakage of Fe2+/His/TCPP coordinate interactions, leading to accelerated release of payloads and the following escape to cytoplasm. Upon laser irradiation, TCPP produces excessive 1O2 followed by conversion to H2O2 in the presence of AscP, which is further catalyzed to lethal •OH by Fe2+ via Fenton reaction. The self-supplying H2O2 was found to result significantly higher accumulation of lipid peroxides and more effective tumor inhibition. Overall, this work sheds new a light on H2O2 self-supplying strategy to enhance ferroptosis by taking advantage of 1O2 generated by photodynamic therapy (PDT).
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.
Singlet oxygen (1O2), as the primary reactive oxygen species in photodynamic therapy, can effectively induce excessive oxidative stress to ablate tumors and kill germs in clinical treatment. However, monitoring endogenous 1O2 is greatly challenging due to its extremely short lifetime and high reactivity in biological condition. Herein, we report an ultra-high signal-to-ratio near-infrared chemiluminescent probe (DCM-Cy) for the precise detection of endogenous 1O2 during photodynamic therapy (PDT). The methoxy moiety was removed from enolether unit in DCM-Cy to suppress the potential self-photooxidation reaction, thus greatly eliminating the photoinduced background signals during PDT. Additionally, the compact cyclobutane modification of DCM-Cy resulted in a significant 6-fold increase in cell permeability compared to conventional adamantane-dioxane probes. Therefore, our "step-by-step" strategy for DCM-Cy addressed the limitations of traditional chemiluminescent (CL) probes for 1O2, enabling effectively tracking of endogenous 1O2 level changes in living cells, pathogenic bacteria and mice in PDT.
Interstitial hypertension and extracellular matrix (ECM) barriers imposed by cancer-associated fibroblasts (CAFs) at the tumor site significantly impede the retention of intratumorally administered oncolytic viruses (OVs) as well as their efficacy in infecting and eradicating tumor cells. Herein, a stable, controllable, and easily prepared hydrogel was developed for employing a differential release strategy to deliver OVs. The oncolytic herpes simplex virus-2 (oH2) particles were loaded within sodium alginate (ALG), together with the small molecule drug PT-100 targeting CAFs. The rapid release of PT-100 functions as an anti-CAFs agent, reducing ECM, and alleviating interstitial pressure at the tumor site. Consequently, the delayed release of oH2 could more effectively invade and eradicate tumor cells while also facilitating enhanced infiltration of immune cells into the tumor microenvironment, thereby establishing an immunologically favorable milieu against tumors. This approach holds significant potential for achieving highly efficient oncolytic virus therapy with minimal toxicity, particularly in tumors rich in stromal components.
Constructing multi-dimensional hydrogen bond (H-bond) regulated single-molecule systems with multi-emission remains a challenge. Herein, we report the design of a new excited-state intramolecular proton transfer (ESIPT) featured chromophore (HBT-DPI) that shows flexible emission tunability via the multi-dimensional regulation of intra- and intermolecular H-bonds. The feature of switchable intramolecular H-bonds is induced via incorporating several hydrogen bond acceptors and donors into one single HBT-DPI molecule, allowing the "turn on/off" of ESIPT process by forming isomers with distinct intramolecular H-bonds configurations. In response to different external H-bonding environments, the obtained four types of crystal/cocrystals vary in the contents of isomers and the molecular packing modes, which are mainly guided by the intermolecular H-bonds, exhibiting non-emissive features or emissions ranging from green to orange. Utilizing the feature of intermolecular H-bond guided molecular packing, we demonstrate the utility of this fluorescent material for visualizing hydrophobic/hydrophilic areas on large-scale heterogeneous surfaces of modified poly(1,1-difluoroethylene) (PVDF) membranes and quantitatively estimating the surface hydrophobicity, providing a new approach for hydrophobicity/hydrophilicity monitoring and measurement. Overall, this study represents a new design strategy for constructing multi-dimensional hydrogen bond regulated ESIPT-based fluorescent materials that enable multiple emissions and unique applications.
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