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1.
Environ Pollut ; 343: 123207, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38154774

ABSTRACT

Inland ponds exhibit remarkable ubiquity across the globe, playing a vital role in the sustainability of global continental freshwater resources and contributing significantly to their biodiversity. Numerous ponds are eutrophic and experience recurrent seasonal or year-round algal blooms or persistent duckweed cover, conferring a characteristic green hue. Here, we denote these eutrophic and green ponds as EGPs. The excessive proliferation of algal blooms and duckweed within these EGPs poses a significant threat to the ecological functioning of these aquatic systems, which can lead to hypoxia or the release of microcystins. To identify these EGPs automatically, we constructed an Efficient Attention Fusion Unet (EAF-Unet) algorithm using Gaofen-2 (GF2) panchromatic and multispectral imagery. The attention mechanism was incorporated in Unet to help better detect EGPs. Using the first EGP labeled dataset, we determined the best input feature combination (RGB, NIR, NDVI, and Bright) and the most effective encoding (Rasnet50) for EAF-Unet for distinguishing EGPs from other ground cover types. The evaluation indices - Precision (0.81), Recall (0.79), F1-Score (0.80), and Intersection over Union (IoU, 0.67) - indicate that EAF-Unet can accurately and robustly extract EGPs from GF2 images without relying on pond water masks. Remote-sensing EGP products can assist in identifying ponds with severe eutrophication. Moreover, these products can serve as references for identifying high-risk areas prone to improper sewage discharge or inadequate sewer construction.


Subject(s)
Fresh Water , Ponds , Eutrophication , Phosphorus
3.
J Transl Med ; 21(1): 461, 2023 07 11.
Article in English | MEDLINE | ID: mdl-37434177

ABSTRACT

BACKGROUND: Nearly 80% of patients with pancreatic cancer suffer from glucose intolerance or diabetes. Pancreatic cancer complicated by diabetes has a more immunosuppressive tumor microenvironment (TME) and is associated with a worse prognosis. The relationship between glucose metabolism and programmed cell death-Ligand 1 (PD-L1) is close and complex. It is important to explore the regulation of high glucose on PD-L1 expression in pancreatic cancer and its effect on infiltrating immune effectors in the tumor microenvironment. METHODS: Diabetic murine models (C57BL/6) were used to reveal different immune landscape in euglycemic and hyperglycemic pancreatic tumor microenvironment. Bioinformatics, WB, iRIP [Improved RNA Binding Protein (RBP) Immunoprecipitation]-seq were used to confirm the potential regulating role of peptidyl-tRNA hydrolase 1 homolog (PTRH1) on the stability of the PD-L1 mRNA. Postoperative specimens were used to identify the expression of PD-L1 and PTRH1 in pancreatic cancer. Co-culturing T cells with pancreatic cancer cells to explore the immunosuppressive effect of pancreatic tumor cells. RESULTS: Our results revealed that a high dose of glucose enhanced the stability of the PD-L1 mRNA in pancreatic tumor cells by downregulating PTRH1 through RAS signaling pathway activation following epidermal growth factor receptor (EGFR) stimulation. PTRH1 overexpression significantly suppressed PD-L1 expression in pancreatic cells and improved the proportion and cytotoxic function of CD8+ T cells in the pancreatic TME of diabetic mice. CONCLUSIONS: PTRH1, an RBP, plays a key role in the regulation of PD-L1 by high glucose and is closely related to anti-tumor immunity in the pancreatic TME.


Subject(s)
Antineoplastic Agents , B7-H1 Antigen , Diabetes Mellitus, Experimental , Pancreatic Neoplasms , Animals , Mice , B7-H1 Antigen/genetics , CD8-Positive T-Lymphocytes , Down-Regulation/genetics , Mice, Inbred C57BL , Pancreatic Neoplasms/genetics , Signal Transduction , Tumor Microenvironment , Pancreatic Neoplasms
4.
ACS Appl Mater Interfaces ; 15(25): 29854-29865, 2023 Jun 28.
Article in English | MEDLINE | ID: mdl-37321566

ABSTRACT

Supramolecular hydrogels prepared using low-molecular-weight gelators have attracted considerable attention for biomedical applications. However, in situ supramolecular hydrogels are limited in terms of their prolonged gelation time and/or unstable nature at high temperatures. In this study, we constructed a stable supramolecular Ag-isoG hydrogel through super-rapid in situ formation, wherein hydrogelation process occurred instantaneously upon mixing isoG and Ag+ within 1 s under ambient conditions. Interestingly, unlike most nucleoside-based supramolecular hydrogels, this Ag-isoG hydrogel remains stable even at a high temperature (100 °C). Moreover, the as-designed hydrogel demonstrated significant antibacterial activity against Staphylococcus aureus and the oral bacterium Streptococcus mutans owing to the strong chelating ability of Ag ions, and the hydrogel exhibited relatively low cytotoxicity in root canal and an easy removal feature by saline. The hydrogel was then applied to a root canal infection model, which demonstrated strong antibacterial activity against Enterococcus faecalis, with performance even better than that of the regular calcium hydroxide paste. This feature makes the Ag-isoG hydrogel a prospective alternative material as intracanal medicaments for root canal treatment.


Subject(s)
Hydrogels , Silver , Hydrogels/pharmacology , Silver/pharmacology , Disinfection , Dental Pulp Cavity , Prospective Studies , Anti-Bacterial Agents/pharmacology , Ions
5.
Cancer Lett ; 565: 216222, 2023 07 01.
Article in English | MEDLINE | ID: mdl-37196908

ABSTRACT

In eukaryotes, N6-methyladenosine (m6A) is the most prevalent epigenetic alteration. Methyltransferase-like 3 (METTL3) is a key player in the control of m6A, although its function in pancreatic cancer is incompletely understood. In this study, we examined the role that METTL3 plays in pancreatic cancer cell proliferation and stemness. We discovered that in pancreatic cancer cells, METTL3-mediated m6A alterations regulate ID2 as a downstream target. The stability of ID2 mRNA was decreased and m6A modification was effectively eliminated by METTL3 knockdown in pancreatic cancer cells. We also demonstrate that m6a-YTHDF2 is necessary for the METTL3-mediated stabilization of ID2 mRNA. Additionally, we show that ID2 controls the stemness molecules NANOG and SOX2 via the PI3K-AKT pathway to support pancreatic cancer growth and stemness maintenance. Our data suggest that METTL3 may post-transcriptionally upregulate ID2 expression in an m6A-YTHDF2-dependent manner to further promote the stabilization of ID2 mRNA, which may be a new target for pancreatic cancer treatment.


Subject(s)
Methyltransferases , Pancreatic Neoplasms , Humans , Methyltransferases/genetics , Methyltransferases/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Phosphatidylinositol 3-Kinases , Transcription Factors , Pancreatic Neoplasms/genetics , Cell Proliferation/genetics , Inhibitor of Differentiation Protein 2 , Pancreatic Neoplasms
6.
Chemistry ; 29(37): e202301100, 2023 Jul 03.
Article in English | MEDLINE | ID: mdl-37051838

ABSTRACT

The mechano-responsiverelease of small molecules has received extensive attention in ultrasound (US)-controlled drug release in recent years because it can achieve non-invasive, spatiotemporally controlled precise drug release. However, the vast majority of small molecules mechano-release reported so far are based on polymer systems, which suffer from complex preparations and single mechano-response. Here, an isoguanosine (isoG) visualized mechano-responsive supramolecular self-assembly (isoG-VMRSS) system was successfully constructed by a one-pot reaction. It is completely composed of small molecules, which allows for multiple mechano-responsive releases of isoG (at least 9 times) and ultimately has potential for application in US drug release. A combined experimental-computational approach reveals the supramolecular network structure (formed by the joint action of related metal coordination bonds, boronate ester bonds and hydrogen bonds mediated by isoG) gradually formed inside the system is the underlying internal mechanism. Therefore, it provides a new and effective idea of small molecule release in the field of mechanochemistry.

7.
bioRxiv ; 2023 Mar 02.
Article in English | MEDLINE | ID: mdl-36909530

ABSTRACT

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodelling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFß/Activin-SMAD2/3 signalling pathway. Inhibition and genetic ablation of BDR9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumours from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs. Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

8.
Cell Mol Gastroenterol Hepatol ; 14(5): 1146-1165, 2022.
Article in English | MEDLINE | ID: mdl-35863742

ABSTRACT

BACKGROUND & AIMS: Accumulating evidence strongly suggests that hyperglycemia promotes the progression of pancreatic cancer (PC). Approximately 80% of patients with PC are intolerant to hyperglycemic conditions. In this study, we define the role of Bmi1, a stemness-related oncogene, in controlling the Warburg effect, and immune suppression under hyperglycemia conditions. METHODS: The diabetes mellitus model was established by intraperitoneal injection of streptozotocin. The role of the hyperglycemia-Bmi1-HK2 axis in glycolysis-related immunosuppression was examined in both orthotopic and xenograft in vivo models. Evaluation of immune infiltrates was carried out by flow cytometry. Human PC cell lines, SW1990, BxPC-3, and CFPAC-1, were used for mechanistic in vitro studies. RESULTS: Through bioinformatics analysis, we found that hyperglycemia was strongly related to aerobic glycolysis, immunosuppression, and cancer cell stemness. High glucose condition in the tumor microenvironment promotes immune suppression by upregulating glycolysis in PC cells, which can be rescued via knockdown Bmi1 expression or after 2-deoxy-D-glucose treatment. Through gain-/loss-of-function assessments, we found that Bmi1 upregulated the expression of UPF1, which enhanced the stability of HK2 mRNA and thereby increased the expression of HK2. The role of the hyperglycemia-Bmi-HK2 pathway in the inhibition of antitumor immunity was further verified via the immune-competent and immunodeficient mice model. We also demonstrated that hyperglycemia promotes the expression of Bmi1 by elevating the intracellular acetyl-CoA levels and histone H4 acetylation levels. CONCLUSIONS: Our results suggest that the previously unreported Bmi1-UPF1-HK2 pathway contributes to PC progression and immunosuppression, which may bring in new targets for developing effective therapies to treat patients with PC.


Subject(s)
Hyperglycemia , Pancreatic Neoplasms , Humans , Mice , Animals , Streptozocin , Acetyl Coenzyme A/metabolism , Histones/metabolism , Pancreatic Neoplasms/genetics , Glycolysis/genetics , RNA, Messenger/genetics , Glucose , Mice, Nude , Immunosuppression Therapy , Deoxyglucose , Tumor Microenvironment , Polycomb Repressive Complex 1/genetics , Polycomb Repressive Complex 1/metabolism , Pancreatic Neoplasms
9.
J Transl Med ; 19(1): 525, 2021 12 24.
Article in English | MEDLINE | ID: mdl-34952605

ABSTRACT

BACKGROUND: The current guidelines of the American Joint Committee on Cancer (AJCC) for the staging of exocrine pancreatic tumors seem inapplicable to malignant pancreatic intraductal papillary mucinous neoplasms (IPMN). Therefore, we aimed to improve the accuracy of clinical staging and prognosis for malignant IPMN by modifiing current AJCC system. METHODS: We extracted data of 2001 patients with malignant IPMN from the Surveillance, Epidemiology, and End Results database between 2000 and 2016. Of these, 1401 patients were assigned to the primary cohort and 600 patients to the validation cohort. RESULTS: In Kaplan-Meier analysis of the primary cohort, the current AJCC guidelines were unable to distinguish between certain tumor substages (IA and IB in the 7th, IB and IIA in the 8th). The modified system that we regrouped based on the median overall survival and hazard ratios, was superior in tumor stage classifications. Age > 70 years, tumors located in the body or tail, high-grade differentiated tumors, surgery, chemotherapy, and tumor, lymph node, and metastasis (TNM) stage were identified as independent predictive factors for overall survival. Compared to that of TNM-based systems, the concordance index of the clinical predictive nomogram significantly improved (0.819; 95% confidence interval, 0.805-0.833), with excellent area under the receiver operating characteristic curves (1-, 3-, and 5-year: 0.881, 0.889, and 0.879, respectively). The calibration curves also showed good agreement between prediction and actual observation. The analysis of treatment modalities revealed that surgery resulted in better survival for all resectable malignant IPMN. The analysis of chemotherapy data reveals its potential in improving the prognosis of treatment for patients with locally advanced or distant metastases. CONCLUSIONS: Our modified staging system improves the distinction of tumor stages. The nomogram was a more accurate and clinically reliable tool for prognosis prediction of patients with malignant IPMN.


Subject(s)
Pancreatic Intraductal Neoplasms , Pancreatic Neoplasms , Aged , Humans , Neoplasm Staging , Nomograms , Pancreatic Intraductal Neoplasms/pathology , Pancreatic Neoplasms/pathology , Prognosis
10.
Dalton Trans ; 50(42): 15170-15175, 2021 Nov 02.
Article in English | MEDLINE | ID: mdl-34617544

ABSTRACT

CeO2 nanocubes with average sizes of 9, 13, and 18 nm have been synthesized by preparing a slightly basic aqueous mixture of Ce(NO3)3, Na2SO4, and NH4OH and heating the solution to 100 to 150 °C in 4 or 9 h. The nanocubes possess high crystalline quality. Their band gaps decrease gradually beyond the quantum confinement regime from 3.57 eV to 3.45 eV with increasing particle sizes. The 9 nm CeO2 nanocubes have the most positive valence band energy and correspondingly they exhibit the best electrochemical oxygen evolution reaction activity. Since band gaps of semiconductor nanocrystals can be tuned substantially through particle size control to yield different band energies, this fact can be utilized to enhance the electrochemical and photocatalytic properties.

11.
Front Mol Biosci ; 8: 727481, 2021.
Article in English | MEDLINE | ID: mdl-34604305

ABSTRACT

Glioma is the most common and aggressive type of primary brain malignant tumor with limited treatment approaches. Methyltransferase-like 7B (METTL7B) is associated with the pathogenesis of several diseases but is rarely studied in glioma. In this study, 1,493 glioma samples (data from our cohort, TCGA, and CGGA) expressing METTL7B were used to explore its prognostic value and mechanism in the immune microenvironment. Results showed that high expression of METTL7B is associated with poor prognosis and abundant immunosuppressive cells. Further, functional enrichment showed that METTL7B is involved in the negative regulation of immunity and carcinogenic signaling pathways. Moreover, a METTL7B-related prognostic signature constructed based on multi-omics showed a good prediction of the overall survival (OS) time of glioma patients. In conclusion, METTL7B is a potential prognostic biomarker. In addition, the prognostic prediction model constructed in this study can be used in clinical setups for the development of novel effective therapeutic strategies for glioma patients and improving overall survival.

12.
Anal Chem ; 93(28): 9737-9743, 2021 07 20.
Article in English | MEDLINE | ID: mdl-34235917

ABSTRACT

D2O plays important roles in a variety of fields (such as the nuclear industry and bioorganic analysis), and thus its isotopic purity (H2O contents) is highly concerned. Due to its highly similar physical properties to H2O and large excess amounts of H2O over D2O, it is challenging to distinguish D2O from H2O. On the basis of the characteristic NIR-II phosphorescence of singlet oxygen (1O2), and the fact that H2O is a more efficient quencher for 1O2 than D2O, here, we proposed to simply use the 1275 nm emission of 1O2 for the analysis of the isotopic purity of D2O. In normal cases (a xenon lamp for excitation), such steady-state emission is extremely weak for valid analytical applications, we thus employed laser excitation for intensification. To this goal, a series of photosensitizers were screened, and eventually polythiophene PT10 was selected with high singlet oxygen quantum yield (ΦΔ = 0.51), high H2O/D2O contrast, and excellent photostability. Upon excitation with a 445 nm laser, a limit of detection (LOD, 3σ) of 0.1% for H2O in D2O was achieved. The accuracy of the proposed method was verified by the analysis of the isotopic purity of several D2O samples (with randomly added H2O). More interestingly, the hygroscopicity of D2O was sensitively monitored with the proposed probe in a real-time manner; the results of which are important for strengthening the care of D2O storage and the importance of humidity control during related investigations. Besides D2O isotopic purity evaluation, this work also indicated the potential usefulness of the NIR-II emission of singlet oxygen in future analytical detection.


Subject(s)
Photosensitizing Agents , Singlet Oxygen , Light , Polymers , Thiophenes
13.
Sci Rep ; 10(1): 17462, 2020 Oct 15.
Article in English | MEDLINE | ID: mdl-33060774

ABSTRACT

Based upon the approximate Crank-Nicolson (CN) finite-difference time-domain method implementation, the unconditionally stable algorithm is proposed to investigate the wave propagation and transmission through extremely thin graphene layers. More precisely, by incorporating the CN Douglas-Gunn algorithm, the piecewise linear recursive convolution method and the auxiliary differential equation method, the analytical model is proposed for Drude-like graphene model. To obtain the solution of the governing equations, the perfectly matched layer and the periodic boundary condition are applied to the graphene structure with two dimensional nano-materials. Numerical examples are carried out for further investigation. During the simulation, the influences of the parameters such as the grating slit and its thickness on the wave transmission are investigated and discussed. The result shows that not only the graphene grating has high transmission performance but also the proposed methods have considerable performance and accuracy.

14.
Front Oncol ; 10: 796, 2020.
Article in English | MEDLINE | ID: mdl-32500034

ABSTRACT

Glioma groups, including lower-grade glioma (LGG) and glioblastoma multiforme (GBM), are the most common primary brain tumor. Malignant gliomas, especially glioblastomas, are associated with a dismal prognosis. Hypoxia is a driver of the malignant phenotype in glioma groups; it triggers a cascade of immunosuppressive processes and malignant cellular responses (tumor progression, anti-apoptosis, and resistance to chemoradiotherapy), which result in disease progression and poor prognosis. However, approaches to determine the extent of hypoxia in the tumor microenvironment are still unclear. Here, we downloaded 575 LGG patients and 354 GBM patients from Chinese Glioma Genome Atlas (GGGA), and 530 LGG patients and 167 GBM patients from The Cancer Genome Atlas (TCGA) with RNA sequence and clinicopathological data. We developed a hypoxia risk model to reflect the immune microenvironment in glioma and predict prognosis. High hypoxia risk score was associated with poor prognosis and indicated an immunosuppressive microenvironment. Hypoxia signature significantly correlated with clinical and molecular features and could serve as an independent prognostic factor for glioma patients. Moreover, Gene Set Enrichment Analysis showed that gene sets associated with the high-risk group were involved in carcinogenesis and immunosuppression signaling. In conclusion, we developed and validated a hypoxia risk model, which served as an independent prognostic indicator and reflected overall immune response intensity in the glioma microenvironment.

15.
Cell Prolif ; 53(5): e12821, 2020 May.
Article in English | MEDLINE | ID: mdl-32364266

ABSTRACT

OBJECTIVES: Photodynamic therapy (PDT) is a promising approach for cancer treatment, and the underlying signalling pathway changes has been carried out for studying the PDT mechanisms, but is majorly limited to organic photosensitizers (PSs). For the emerging nano-PSs typically possessing higher 1 O2 quantum yield, few mechanistic studies were carried out, which limited their further applications in clinical therapeutics. PI3K/Akt signalling pathway, a most frequently activated signalling network in cancers, could promote cancer cell survival, but was seldom reported in previous PDT studies mediated by nano-PSs. MATERIALS AND METHODS: Sulphur doped carbon dots (S-CDs) was prepared via a hydrothermal synthetic route and was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and so on. CCK-8 assay and Annexin V/PI staining were performed to demonstrate the death of cancer cells, Western blot, RT-PCR and immunofluorescence were employed to explore the underlying mechanism, and variation of PI3K/Akt and other signalling pathways was detected by Western blot. RESULTS: S-CDs was successfully synthesized, and it was much more efficient compared with classic organic PSs. S-CDs could induce cancer cell death through mitochondria mediated cell apoptosis with the imbalance of Bcl-2 family proteins and caspase cascade via several signalling pathways. Low concentration of S-CDs could effectively inhibit PI3K/Akt pathway and promote p38/JNK pathway, on one way inhibiting cancer cell survival and on the other way promoting cell apoptosis. CONCLUSIONS: Herein, we found that S-CDs acted as an inhibitor of the PI3K/Akt pathway for efficient cancer cell killing, thus yielding in a higher PDT performance over the existing photosensitizers.


Subject(s)
Carbon/pharmacology , Neoplasms/drug therapy , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Sulfur/pharmacology , Apoptosis/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Humans , MAP Kinase Signaling System/drug effects , Mitochondria/drug effects , Mitochondria/metabolism , Neoplasms/metabolism , Photochemotherapy/methods , Photosensitizing Agents/pharmacology , Proto-Oncogene Proteins c-bcl-2/metabolism
16.
Mol Ther Oncolytics ; 17: 21-30, 2020 Jun 26.
Article in English | MEDLINE | ID: mdl-32300640

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancers due to frequently late diagnosis and futile treatment. It is a crucial necessity to determine the mechanisms of PDAC. Y-box Binding Protein 1 (YBX1), a highly conserved transcription factor, has been previously reported to play a role in various hallmarks of cancer. We show here that YBX1 is significantly overexpressed in PDAC and correlates with poor prognosis and reduced survival. In PDAC cell lines, YBX1 regulated cell-cycle progression, proliferation, and the expression of glycogen synthase kinase 3 beta (GSK3B) and cell-cycle-related proteins cyclin D1 and E1. Dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assays established that YBX1 binds to the promoter of GSK3B, suggesting that YBX1 promotes pancreatic cancer cell growth through induction of GSK3B expression. These findings offer important insights into the mechanisms underlying pathologic proliferation in PDAC.

17.
Theranostics ; 10(11): 4871-4884, 2020.
Article in English | MEDLINE | ID: mdl-32308755

ABSTRACT

Rationale: Accumulating evidence supports the importance of radiation therapy in the induction of antitumor immunity. Small extracellular vesicles (sEVs) play essential roles in tumor antigen loading and delivery. However, the role of sEVs in radiation-induced antitumor immunity remains unclear. It is therefore important to determine the role and regulatory mechanisms of sEVs in radiation-induced immunity. Methods: Tumor cells were irradiated (8 Gy), and sEVs were purified via ultracentrifugation. Primary tumor and experimental lung metastasis models were established in mice to evaluate antitumor immunity triggered by immunization with sEVs. Proteomic and bioinformatic analyses were performed to identify altered cargos in sEVs induced by radiation. Peptides derived from up-regulated proteins in sEVs were designed and synthesized as vaccines according to major histocompatibility complex (MHC) I binding and immunogenicity. Results: Here, we demonstrated that sEVs derived from irradiated tumor cells could trigger antitumor immunity against primary tumor and experimental lung metastasis by enhancing CD8+ and CD4+ T cell infiltration. Radiation may also enrich sEVs with tumor antigens and heat-shock proteins. Furthermore, CUB domain-containing protein 1 (CDCP1) derived from radiation-induced sEVs was identified as a novel tumor-associated antigen and developed as a peptide vaccine that may generate antitumor immune responses. Conclusions: Our results demonstrate that the use of sEVs secreted by irradiated tumor cells constitutes an efficient approach for tumor antigen delivery and presentation and highlight the role of sEVs in radiation-triggered antitumor immunity.


Subject(s)
Antigens, Neoplasm/immunology , Breast Neoplasms/radiotherapy , Extracellular Vesicles/immunology , Immunity, Cellular , Liver Neoplasms/radiotherapy , Radiotherapy/methods , T-Lymphocytes/immunology , Animals , Antigens, Neoplasm/metabolism , Breast Neoplasms/immunology , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cancer Vaccines/immunology , Cell Adhesion Molecules/immunology , Cell Line, Tumor , Disease Models, Animal , Extracellular Vesicles/metabolism , Extracellular Vesicles/radiation effects , Female , Liver Neoplasms/immunology , Liver Neoplasms/metabolism , Liver Neoplasms/secondary , Mice , Mice, Inbred BALB C , Peptides/immunology , T-Lymphocytes/metabolism , T-Lymphocytes/radiation effects
18.
Nanoscale ; 12(9): 5543-5553, 2020 Mar 05.
Article in English | MEDLINE | ID: mdl-32091517

ABSTRACT

Photosensitization is a promising avenue of oxygen activation, which can overcome the spin selection rule to transform the ground state oxygen (3O2) into a highly reactive singlet oxygen (1O2). Carbon dots (CDs) are a promising type of carbon-based photosensitizer, and nitrogen doping can further improve the oxygen photosensitization performance. Although the roles of nitrogen doping in tuning the optical properties (mainly absorption and fluorescence) of CDs have been well-studied, their association with oxygen photosensitization has not been reported. Herein, using the well-developed synthetic protocol of hydrothermal treatment of citric acid and ethylenediamine, we prepared nitrogen-doped CDs (N-CDs) of varied nitrogen contents. The oxygen photosensitization performances of the N-CDs were first confirmed by ROS investigation with TMB oxidation as the ROS probe and EPR. After XPS analysis of the surface nitrogen doping speciation, it was found that the changes of graphitic N and pyrrolic N correlated well with the oxygen photosensitization performances of N-CDs. Further theoretical calculations indicated that the two key factors for oxygen photosensitization, namely triplet activation and oxygen adsorption, are mainly associated with graphitic N and pyrrolic N, respectively. The results in this work help further understanding of the oxygen photosensitization mechanism of N-CDs, and are expected to be useful in the future design of carbon-based photosensitizers.

19.
J Mater Chem B ; 8(16): 3640-3646, 2020 04 29.
Article in English | MEDLINE | ID: mdl-31967181

ABSTRACT

Carbon dots (Cdots) play an important role in many biological and chemical applications. To prepare strongly fluorescent Cdots, the starting material should contain nitrogen in addition to carbon. Nucleobases are nitrogen rich with interesting metal binding properties. In this work, we prepared a series of Cdots with citrate as the carbon source, and ethylenediamine, adenosine, cytidine, thymidine or guanosine as the respective nitrogen sources. The resulting Cdots were all fluorescent with the ethylenediamine sample being the most strongly emissive. These Cdots were then tested for their metal sensitivity and all tested metal ions can quench their fluorescence. The fluorescence of the G-Cdots prepared with guanosine was quenched most efficiently by Cu2+, while the Cdots prepared with ethylenediamine were more sensitive to Hg2+. With the differential quenching by different metal ions, we prepared a sensor array to discriminate multiple metal ions, and quantified Cu2+ and Hg2+ at the same time. Our work has expanded the range of starting materials for preparing Cdots and showed that by tuning the precursor composition, Cdots with different optical and metal binding properties can be obtained, which is useful in constructing a sensing platform for a large number of metal ions.


Subject(s)
Carbon/chemistry , Copper/analysis , Fluorescent Dyes/chemistry , Mercury/analysis , Nucleosides/chemistry , Quantum Dots/chemistry , Fluorescent Dyes/chemical synthesis , Molecular Structure , Particle Size , Spectrometry, Fluorescence , Surface Properties
20.
ACS Nano ; 13(12): 14152-14161, 2019 12 24.
Article in English | MEDLINE | ID: mdl-31769964

ABSTRACT

Singlet oxygen (1O2) plays a central role in photochemical and photobiological research. Although many photosensitizers for efficient 1O2 generation were reported, further improving its yield and oxidation power is still highly desirable. Instead of developing new ones, current photosensitizers might be boosted by mediators to facilitate energy transfer. Taking advantage of the long triplet state lifetime of lanthanide ions (Ln3+), we herein demonstrate their roles as potent oxidation mediators. Using oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) at neutral pH as a difficult model reaction, based on the fluorescence, phosphorescence, and metal-binding properties, various dyes and nanomaterials were classified into four types. The 1O2 emission of carbon dots and rose bengal was enhanced 4 times in the presence of Ce3+. Some nonphosphorescent, but strongly fluorescent dyes that are not known as photosensitizers can still be mediated by Ln3+ to produce 1O2, but metal-chelating calcein was not enhanced. Finally, nonemissive dyes failed to show activity. As mediators, the excited Ln3+ can migrate a long distance and transfer energy to O2, resulting in high 1O2 yield. Since redox-active Ce3+ and Eu3+ had the highest activity, participation of oxidation involving excited lanthanides might be possible too. In addition, Ln3+ also enhanced the activity of graphene quantum dots, graphene oxide, and g-C3N4. Rapid degradation of organic dyes was demonstrated, further supporting a high photocatalytic activity of the Ln3+-mediated system.


Subject(s)
Lanthanoid Series Elements/chemistry , Light , Photosensitizing Agents/chemistry , Singlet Oxygen/chemistry , Benzidines/chemistry , Carbon/chemistry , Catalysis , Coloring Agents/chemistry , Hydrogen-Ion Concentration , Ions , Nanostructures/chemistry , Nanostructures/ultrastructure , Oxidation-Reduction , Spectrometry, Fluorescence
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