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1.
Ecotoxicol Environ Saf ; 263: 115195, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37418937

RESUMO

Biological organisms are exposed to low-dose arsenic or N-nitro compounds (NOCs) alone or in combination worldwide, especially in areas with high cancer prevalence through drinking water or food exposure; however, information on their combined exposure effects is limited. Here, we conducted an in-depth study of the effects on the gut microbiota, metabolomics, and signaling pathways using rat models exposed to arsenic or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), one of the most active carcinogenic NOCs, separately or in combination with metabolomics and high-throughput sequencing. Compared to exposure alone, combined exposure to arsenic and MNNG exacerbated damage to gastric tissue morphology, interfered with intestinal microflora and substance metabolism, and exerted a stronger carcinogenic effect. This may be related to intestinal microbiota disorders, including Dyella, Oscillibacter, Myroides, and metabolic pathways such as glycine, serine, and threonine metabolism, arginine biosynthesis, central carbon metabolism in cancer, and purine and pyrimidine metabolism, thereby enhancing the cancer-causing effects of gonadotrophin-releasing hormone (GnRH), P53, and Wnt signaling pathways.


Assuntos
Arsênio , Microbioma Gastrointestinal , Neoplasias Gástricas , Ratos , Animais , Metilnitronitrosoguanidina/toxicidade , Arsênio/toxicidade , Metaboloma
2.
Chem Soc Rev ; 51(14): 6177-6209, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35792133

RESUMO

In recent years, lanthanide (Ln) porphyrinoids have received increasing attention as theranostics. Broadly speaking, the term 'theranostics' refers to agents designed to allow both disease diagnosis and therapeutic intervention. This Review summarises the history and the 'state-of-the-art' development of Ln porphyrinoids as theranostic agents. The emphasis is on the progress made within the past decade. Applications of Ln porphyrinoids in near-infrared (NIR, 650-1700 nm) fluorescence imaging (FL), magnetic resonance imaging (MRI), radiotherapy, and chemotherapy will be discussed. The use of Ln porphyrinoids as photo-activated agents ('phototheranostics') will also be highlighted in the context of three promising strategies for regulation of porphyrinic triplet energy dissipation pathways, namely: regioisomeric effects, metal regulation, and the use of expanded porphyrinoids. The goal of this Review is to showcase some of the ongoing efforts being made to optimise Ln porphyrinoids as theranostics and as phototheranostics, in order to provide a platform for understanding likely future developments in the area, including those associated with structure-based innovations, functional improvements, and emerging biological activation strategies.


Assuntos
Elementos da Série dos Lantanídeos , Imageamento por Ressonância Magnética/métodos , Medicina de Precisão , Nanomedicina Teranóstica/métodos
3.
Angew Chem Int Ed Engl ; 61(43): e202208707, 2022 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-35989247

RESUMO

We report here the development of clickable and highly near-infrared (NIR) fluorescent lanthanide (Ln) complexes for bioorthogonal labeling of biomolecules. These azide- or alkyne-functionalized Ln complexes are hydrophilic and fluorogenic, exhibiting a strong increase of NIR fluorescence upon conjugation with biomolecules. Metabolic labeling of biomolecules with azide or alkyne, followed by click labeling with the Ln complexes, enables NIR fluorescence (NIRF) imaging of DNA, RNA, proteins, and glycans in cells. Furthermore, multicolor imaging is performed by combining click-labeling with the Ln complexes and immunostaining. In addition, the Ln complexes is compatible with click-expansion microscopy (click-ExM), which enables high-resolution NIRF imaging of cellular glycoproteins. Finally, the Ln complexes can be used for time-of-flight secondary-ion mass spectrometry (ToF-SIMS) imaging, thus achieving the first example of dual-modal imaging combining NIRF and SIMS microscopies.


Assuntos
Elementos da Série dos Lantanídeos , Elementos da Série dos Lantanídeos/química , Azidas/química , Sondas Moleculares , Alcinos/química , RNA , Glicoproteínas , Espectrometria de Massas , Polissacarídeos , Corantes Fluorescentes/química , Química Click/métodos
4.
Acc Chem Res ; 52(9): 2620-2633, 2019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31298833

RESUMO

Chlorophylls, known as the key building blocks of natural light-harvesting antennae, are essential to utilize solar energy from visible to near-infrared (NIR) region during the photosynthesis process. The fundamental studies for the relationship between structure and photophysical properties of chlorophylls disclosed the importance of ß-peripheral modification and thus boosted the fast growth of NIR absorbing/emissive porphyrinoids via altering the extent of π-conjugation and the degree of distortion from the planarity of macrocycle. Despite the tremendous progress made in various porphyrin-based synthetic models, it still remains a challenge to precisely modulate photophysical properties through fine-tuning of ß-peripheral structures in the way natural chlorophylls do. With this in mind, we initiated a program and focused on meso-C6F5-substituted porpholactone (F20TPPL), in which one ß-pyrrolic double bond was replaced by a lactone moiety, as an attractive platform to construct the bioinspired library of NIR porphyrinoids. In this Account, we summarize our recent contributions to the bioinspired design, synthesis, photophysical characterization, and applications of porpholactones and their derivatives. We have developed a general, convenient method to directly prepare porpholactones in large scale up to gram, which forms the chemical basis of porpholactone chemistry. By modulation of the saturation level and in particular regioisomerization of ß-dilactone moieties, a synthetic library constituted by a series of porpholactones and their derivatives has been established. Thanks to the electron-withdrawing nature of lactone moiety, derivation of the saturation levels gives help to build stable models for chlorin, bacteriochlorin, and tunichlorin. It is worth noting that regioisomerization of dilactone moieties mimics the relative orientation of ß-substituents in natural chlorophylls and hemes, which was considered as the key factor to tune NIR absorption and reactivity. Porpholactones can illustrate the capability of fine-tuning photophysical properties including the excited triplet states by subtle alteration of ß-peripheral structures in the presence of transition metals and lanthanides (Ln). Furthermore, they can serve as efficient photosensitizers for singlet oxygen and NIR Ln, showing potential applications in cell imaging and photocytotoxicity studies. The high luminescence, tunable structures, high cellular uptake, and intense NIR absorption render them as promising and competitive candidates for theranostics in vitro and in vivo. Therefore, extending the studies of "porpholactone chemistry" not only tests the fundamental understanding of the structure-function relationship that governs NIR photophysical properties of natural tetrapyrrole cofactors such as chlorophylls but also provides the guiding principles for the bioinspired design of NIR luminescent molecular probes with various applications. Taken together, as a new synthetic porphyrin derivative, porpholactone chemistry shines light on synthetic porphyrin, bioinorganic, and lanthanide chemistry.


Assuntos
Lactonas/química , Fármacos Fotossensibilizantes/química , Porfirinas/química , Raios Infravermelhos , Lactonas/síntese química , Estrutura Molecular , Processos Fotoquímicos , Fármacos Fotossensibilizantes/síntese química
5.
J Environ Manage ; 266: 110569, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32310118

RESUMO

High input - high output greenhouse vegetable systems are responsible for nutrient surpluses and environmental losses. Integrated strategies that improve soil, crop and nutrient management are needed to ensure more sustainable production systems. We conducted a two-year field experiment to evaluate the potential of integrated soil-crop system management (ISSM) practices to improve the productivity and environmental outcomes from an intensive greenhouse tomato production system in the Yangtze River Basin, China. Four treatments were tested: i) farmers' practice (FP); ii) soil remediation (SR), where lime nitrogen with compost addition was the only management strategy; iii) a treatment that combined soil remediation with optimized crop planting density (SRCO), which increased planting density for improving crop yield; and iv) integrated soil-crop system management (ISSM), as a systematic integrated approach, which included the combined optimization of soil remediation, crop optimization, and nutrient management. In the integrated soil-crop system management treatment, nutrient management was optimized through adoption of the most appropriate type (formula) of fertilizer for the crop, rate and application timing of synthetic fertilizer, and by substituting poultry manure with compost. Our results indicated that the fruit yield of the integrated soil-crop system management treatment was 104 t ha-1, 13.4%-37.3% higher than that of the other three treatments. The mean reactive nitrogen loss (81.1 kg N ha-1) and the greenhouse gas emissions (6495 kg CO2-eq ha-1) in the farmers' practice treatment were much higher than in the other three treatments (reactive nitrogen loss: 47.9-54.3 kg N ha-1; and greenhouse gas emissions: 4926-5468 kg CO2-eq ha-1, respectively). The mean nitrogen and carbon footprints of the integrated soil-crop system management treatment were significantly lower than those of other treatments, as a result of both the lower fertilizer nitrogen use and the greater yield. This study indicates that integrated soil-crop system management could produce greater yields and increase net profit with reduced nitrogen inputs, whilst reducing the environmental cost associated with conventional farmers' practice in plastic-greenhouse vegetable production systems.


Assuntos
Solanum lycopersicum , Agricultura , China , Fertilizantes , Nitrogênio , Solo
6.
Clin Sci (Lond) ; 133(3): 425-441, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30679264

RESUMO

MiRNAs regulate the cardiomyocyte (CM) cell cycle at the post-transcriptional level, affect cell proliferation, and intervene in harmed CM repair post-injury. The present study was undertaken to characterize the role of let-7i-5p in the processes of CM cell cycle and proliferation and to reveal the mechanisms thereof. In the present study, we used real-time qPCR (RT-qPCR) to determine the up-regulated let-7i-5p in CMs during the postnatal switch from proliferation to terminal differentiation and further validated the role of let-7i-5p by loss- and gain-of-function of let-7i-5p in CMs in vitro and in vivo We found that the overexpression of let-7i-5p inhibited CM proliferation, whereas the suppression of let-7i-5p significantly facilitated CM proliferation. E2F2 and CCND2 were identified as the targets of let-7i-5p, mediating its effect in regulating the cell cycle of CMs. Supperession of let-7i-5p promoted the recovery of heart function post-myocardial infarction by enhancing E2F2 and CCND2. Collectively, our results revealed that let-7i-5p is involved in the regulation of the CM cell cycle and further impacts proliferation, which may offer a new potential therapeutic strategy for cardiac repair after ischemic injury.


Assuntos
Proliferação de Células , Ciclina D2/metabolismo , Fator de Transcrição E2F2/metabolismo , MicroRNAs/genética , Miócitos Cardíacos/metabolismo , Animais , Ciclo Celular , Células Cultivadas , Ciclina D2/genética , Fator de Transcrição E2F2/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/citologia
7.
J Mol Cell Cardiol ; 122: 152-164, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30125571

RESUMO

Long noncoding RNAs (lncRNAs) play critical roles in the development of myocardial hypertrophy and may stimulate endogenous myocardial regeneration to prevent heart failure after myocardial infarction (MI). However, whether lncRNAs are involved in regulating myocardial regeneration after MI remains unclear. The present study aimed to identify human-derived lncRNAs that are involved in endogenous cardiomyocyte (CM) regeneration. By analyzing publicly available RNA-seq data of human fetal and normal adult cardiac tissues, we identified a novel human-derived adult upregulated lncRNA designated cardiomyocyte regeneration-related lncRNA (CRRL). Bioinformatics analysis indicated that CRRL is involved in the negative regulation of CM proliferation. First, we observed that the loss of CRRL attenuates post-MI remodeling and preserves cardiac function in adult rats. Through loss-of-function approaches, we found that CRRL knockdown promotes neonatal rat CM proliferation both in vivo and in vitro. Furthermore, we demonstrated that CRRL acts as a competing endogenous RNA (ceRNA) by directly binding to miR-199a-3p and thereby increasing the expression of Hopx, a target gene of miR-199a-3p and a critical negative regulatory factor of CM proliferation. Thus, CRRL suppresses cardiomyocyte regeneration by directly binding to miR-199a-3p, indicating that loss of CRRL facilitates myocardial regeneration and may be a new potential therapeutic strategy for heart failure.


Assuntos
Infarto do Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Regeneração/fisiologia , Análise de Variância , Animais , Cardiomegalia/metabolismo , Proliferação de Células , Biologia Computacional , Bases de Dados de Ácidos Nucleicos , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Proteínas de Homeodomínio/metabolismo , Humanos , MicroRNAs/metabolismo , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica , Estatísticas não Paramétricas , Transfecção , Remodelação Ventricular
8.
Int J Med Robot ; 19(1): e2467, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36251332

RESUMO

BACKGROUND: Compared to traditional rigid robotic arms, soft robotic arms are flexible, environmentally adaptable and biocompatible. Recently, most minimally invasive cardiac procedures still rely on traditional rigid surgical tools. However, rigid tools lack sufficient bending angles, which are high-risk in terms of contact with tissues and organs. METHODS: A soft robotic arm with multiple degrees of freedom was designed to repair atrial septal defects in cardiac surgery. The developed multi-module soft robotic arm consists of four different units, including a bending unit, a turning unit, a stretching unit and gripper units. The three movement units can reach the specified position, and the gripper units can hold a surgical tool stably, such as a suture needle in cardiac surgery. RESULTS: A cardiac surgery to repair an atrial septal defect has been completed, validating the reliability and functionality of the developed multi-module soft robotic arm. CONCLUSIONS: The multi-module flexible soft robotic arm for minimally invasive surgery proposed in this paper can reach the designated surgical area during surgery to repair Atrial Septal Defects. Meanwhile, the design of the actuator of the robot arm was used a completely soft silicone material replacing the rigid material, which releases the contact trauma of the organs during the surgery.


Assuntos
Procedimentos Cirúrgicos Robóticos , Robótica , Humanos , Reprodutibilidade dos Testes , Desenho de Equipamento , Procedimentos Cirúrgicos Minimamente Invasivos , Agulhas
9.
Chem Sci ; 14(8): 2070-2081, 2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36845938

RESUMO

Bioconjugation, a synthetic tool that endows small molecules with biocompatibility and target specificity through covalent attachment of a biomolecule, holds promise for next-generation diagnosis or therapy. Besides the establishment of chemical bonding, such chemical modification concurrently allows alteration of the physicochemical properties of small molecules, but this has been paid less attention in designing novel bioconjugates. Here, we report a "two birds one stone" methodology for irreversible porphyrin bioconjugation based on ß-fluoropyrrolyl-cysteine SNAr chemistry, in which the ß-fluorine of porphyrin is selectively replaced by a cysteine in either peptides or proteins to generate novel ß-peptidyl/proteic porphyrins. Notably, due to the distinct electronic nature between fluorine and sulfur, such replacement makes the Q band red-shift to the near-infrared region (NIR, >700 nm). This facilitates intersystem crossing (ISC) to enhance the triplet population and thus singlet oxygen production. This new methodology features water tolerance, a fast reaction time (15 min), good chemo-selectivity, and broad substrate scope, including various peptides and proteins under mild conditions. To demonstrate its potential, we applied porphyrin ß-bioconjugates in several scenarios, including (1) cytosolic delivery of functional proteins, (2) metabolic glycan labeling, (3) caspase-3 detection, and (4) tumor-targeting phototheranostics.

10.
Top Curr Chem (Cham) ; 380(5): 31, 2022 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-35715540

RESUMO

Near-infrared (NIR, 700-1700 nm) luminescent imaging is an emerging bioimaging technology with low photon scattering, minimal autofluorescence, deep tissue penetration, and high spatiotemporal resolution that has shown fascinating promise for NIR imaging-guided theranostics. In recent progress, NIR luminescent metal complexes have attracted substantially increased research attention owing to their intrinsic merits, including small size, anti-photobleaching, long lifetime, and metal-centered NIR emission. In the past decade, scientists have contributed to the advancement of NIR metal complexes involving efforts to improve photophysical properties, biocompatibility, specificity, pharmacokinetics, in vivo visualization, and attempts to exploit new ligand platforms. Herein, we summarize recent progress and provide future perspectives for NIR metal complexes, including d-block transition metals and f-block lanthanides (Ln) as NIR optical molecular probes for bioassays.


Assuntos
Complexos de Coordenação , Elementos da Série dos Lantanídeos , Bioensaio , Luminescência
11.
Mol Med Rep ; 26(6)2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36281911

RESUMO

Epidermal stem cells (EpSCs) with high expression of regulatory factor Nanog can promote wound healing. The aim of the present study was to investigate the effectiveness and mechanism of epidermal stem cells (EpSCs) in healing scalds and the underlying molecular mechanism. Mouse EpSCs were isolated from skin tissues and cultured in vitro. First, the proliferative ability of EpSCs was determined via the upregulation and downregulation of Nanog expression levels in EpSCs using the MTS­assay. Second, a wound healing assay of the EpSCs with different Nanog expression levels was performed to investigate cell migratory capacities. Third, the protein expression levels of various proteins in EpSCs with Nanog overexpression or knockdown, were determined. Finally, the transfected EpSCs were applied to the rat scald model to observe their effect on scald healing. Subsequently, wound scores, re­epithelialization and capillary density were determined histologically. The results demonstrated that Nanog overexpression enhanced the proliferative ability of EpSCs via cellular (c)­Myc. Moreover, the LV­Nanog group of EpSCs with increased Nanog expression levels exhibited improved healing abilities in the wound healing test than control group. Using western blotting, it was demonstrated that EpSCs that were transfected with a Nanog­overexpression vector expressed high Nanog protein expression levels, whereas small interfering RNA­Nanog­transfected EpSCs exhibited low Nanog protein expression levels. Furthermore, c­Myc expression was synchronized with Nanog expression. It was also revealed that as the expression levels of c­Myc increased, p53 expression levels also increased. In the rat scald model, Nanog­overexpressing EpSCs enhanced wound closure and re­epithelialization. The EpSCs with Nanog knockdown exhibited the opposite effects. The present study therefore indicated that Nanog may have a positive effect on scald healing in rats, which supports its use in EpSC­based treatments against scalds. Furthermore, it was suggested that c­Myc potentially serves a key role in this process and that this process avoids cancerization by relying on the supervision of p53.


Assuntos
Queimaduras , Proteína Supressora de Tumor p53 , Camundongos , Ratos , Animais , RNA Interferente Pequeno/metabolismo , Proteína Homeobox Nanog/genética , Proteína Homeobox Nanog/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Cicatrização/genética , Células-Tronco/metabolismo , Queimaduras/metabolismo
12.
Curr Opin Chem Biol ; 66: 102097, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34775149

RESUMO

Biological imaging and biosensing from subcellular/cellular level to whole body have enabled non-invasive visualisation of molecular events during various biological and pathological processes, giving great contributions to the rapid and impressive advances in chemical biology, drug discovery, disease diagnosis and prognosis. Optical imaging features a series of merits, including convenience, high resolution, good sensitivity, low cost and the absence of ionizing radiation. Among different luminescent probes, metal-based molecules offer unique promise in optical bioimaging and biosensing in vitro and in vivo, arising from their small sizes, strong luminescence, large Stokes shifts, long lifetimes, high photostability and tunable toxicity. In this review, we aim to highlight the design of metal-based molecular probes from the standpoint of synthetic chemistry in the last 2 years for optical imaging, covering d-block transition metal and lanthanide complexes and multimodal imaging agents.


Assuntos
Técnicas Biossensoriais , Elementos da Série dos Lantanídeos , Elementos de Transição , Diagnóstico por Imagem , Luminescência , Sondas Moleculares
13.
Membranes (Basel) ; 12(12)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36557115

RESUMO

Solar-driven interfacial evaporation technology has been identified as a promising method to relieve the global water crisis, and it is particularly important to design an ideal structure of the solar thermal conversion evaporation device. In this paper, hydrophilic polyphenylene sulfide (HPPS) paper with loose structure and appropriate water transmission performance was designed as the based-material, and multi-walled carbon nanotubes (MWCNTs) layer with excellent photothermal conversion performance was constructed to realize the high-efficiency solar-driven evaporation. Under tail swabbing mode, the cold evaporation surface on the back of the evaporator greatly improved the evaporation rate, cut off the heat transfer channel to bulk water, and achieved the maximum evaporation rate of 1.23 L/m2·h. Ethyl cellulose (EC) was introduced to adjust the water supply performance of HPPS layer, and a large specific surface area of cold evaporation was obtained, thus improving the water evaporation rate. In the simulation experiment of seawater desalination and dye wastewater treatment, it showed good water purification capacity and acid/alkali-resistance, which had great practical application significance.

14.
Chem Asian J ; 17(10): e202200181, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35343080

RESUMO

Molecular phototheranostics as an emerging field of modern precision medicine has recently attracted increasing research attention owing to non-invasiveness, high precision, and controllable nature of light. In this work, we reported promising gadolinium (Gd3+ ) porphyrinoids as phototheranostic agents for magnetic resonance imaging (MRI) and photodynamic therapy (PDT). The synthesized Gd-1-4-Glu featured with meso-glycosylation and ß-lactonization to endow good biocompatibility and improved photophysical properties. In particular, ß-lactonization of glycosylated Gd3+ porphyrinoids substantially red-shifted Q band absorption to near-infrared (NIR) region and boosted generation of reactive oxygen species including 1 O2 , and some radical species that engaged in both type II and type I PDT pathways. In addition, the number and regioisomerism of ß-oxazolone moieties was observed to play an essential role in improving longitude relaxivity (r1 ) of Gd-1-4-Glu of up to 4.3±0.2 mM-1 s-1 by affecting environmental water exchange. Taking Gd-4-Glu as a promising complex, we further achieved real-time T1 -weighted MRI and PDT on HeLa tumour mice in vivo, revealing the appealing potential of Gd3+ porphyrinoids in phototheranostics.


Assuntos
Gadolínio , Fotoquimioterapia , Animais , Gadolínio/farmacologia , Células HeLa , Humanos , Imageamento por Ressonância Magnética/métodos , Camundongos , Medicina de Precisão
15.
Chempluschem ; 86(1): 4, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33215795

RESUMO

Invited for this month's cover is the group of Jun-Long Zhang, Peking University, Beijing. The cover picture shows the porpholactone cofactor, which play unique roles in molecular imaging and therapy (or theranostics), catalysis, as well as energy and optical materials. This class of molecules is ideal for more intriguing scientific research and future practical applications. Read the full text of the Minireview at 10.1002/cplu.202000494.

16.
Chempluschem ; 86(1): 71-81, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32844583

RESUMO

The emergence of porpholactone chemistry, discovered over 30 years ago, has significantly stimulated the development of biomimetic tetrapyrrole chemistry. It offers an opportunity, through modifications of non-pyrrolic building blocks, to clarify the relationship between chemical structure and excited-state properties, deciphering the structural code for the biological functions of life pigments. With intriguing photophysical properties in the red to near-infrared (NIR) regions, facile modulation of their electronic nature by fine-tuning chemical structures, and coordination ability with diverse metal ions, these novel porphyrinoids have favorable prospects in the fields of optical materials, bioimaging and therapy, and catalysis. In this Minireview, we summarize the brief history of porpholactone chemistry, and focus on the studies carried out in our group, particularly on the regioisomeric effect, NIR lanthanide luminescence, and metal catalysis. We outline the perspectives of these compounds in the construction of porpholactone-related biomedical applications and optical and energy materials, in order to inspire more interest and further advance bioinspired inorganic chemistry and lanthanide chemical biology.

17.
ACS Macro Lett ; 10(10): 1315-1320, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-35549049

RESUMO

Three-dimensional (3D) printing utilizing controlled polymerization systems is emerging as a powerful approach to fabricate "living" objects, which can be further modified with various functionalities. Here, we report photoinduced free radical-promoted cationic reversible addition-fragmentation chain transfer (RAFT) polymerization under broad wavelengths from ultraviolet (UV) to near-infrared (NIR) light. A commercially available iron catalyst, cyclopentadienyl iron dicarbonyl dimer (Fe2(Cp)2(CO)4), was used as the photocatalyst, and several diphenyliodonium salts were examined as oxidants. Various poly(vinyl ether)s with controlled molecular weights and a narrow dispersity (1.06-1.32) were prepared through this method. Relatively high chain-end fidelity can be observed and has been demonstrated by successful chain-extension experiments. In addition, benefiting from the penetrating ability of NIR light, 3D objects with different thicknesses were achieved by employing stereolithography-based 3D printing techniques. Furthermore, the postfunctionalization of these 3D printed objects with fluorescent monomers provides a facile method to build 3D objects with complex functionality and potential applications in anticounterfeiting materials.


Assuntos
Polímeros , Impressão Tridimensional , Cátions , Radicais Livres , Ferro , Polimerização
18.
Adv Mater ; 33(12): e2008486, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33576082

RESUMO

Human fingers exhibit both high sensitivity and wide tactile range. The finger skin structures are designed to display gradient microstructures and compressibility. Inspired by the gradient mechanical Young's modulus distribution, an electric-field-induced cationic crosslinker migration strategy is demonstrated to prepare gradient ionogels. Due to the gradient of the crosslinkers, the ionogels exhibit more than four orders of magnitude difference between the anode and the cathode side, enabling gradient ionogel-based flexible iontronic sensors having high-sensitivity and broader-range detection (from 3 × 102 to 2.5 × 106  Pa) simultaneously. Moreover, owing to the remarkable properties of the gradient ionogels, the flexible iontronic sensors also show good long-time stability (even after 10 000 cycles loadings) and excellent performance over a wide temperature range (from -108 to 300 °C). The flexible iontronic sensors are further integrated on soft grips, exhibiting remarkable performance under various conditions. These attractive features demonstrate that gradient ionogels will be promising candidates for smart sensor applications in complex and extreme conditions.

19.
Aging (Albany NY) ; 13(17): 21268-21282, 2021 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-34497154

RESUMO

Temozolomide (TMZ) is used for the treatment of high-grade gliomas. Acquired chemoresistance is a serious limitation to the therapy with more than 90% of recurrent gliomas showing little response to a second line of chemotherapy. Therefore, it is necessary to explore an alternative strategy to enhance the sensitivity of glioblastoma (GBM) to TMZ in neuro-oncology. Celecoxib is well known and widely used in anti-inflammatory and analgesic. Cyclooxygenase-2 (COX-2) expression has been linked to the prognosis, angiogenesis, and radiation sensitivity of many malignancies such as primitive neuroectodermal tumor and advanced melanoma. The objective of this study was to explore the chemotherapy-sensitizing effect of celecoxib on TMZ in GBM cells and its potential mechanisms. From the study, we found that the combination therapy (TMZ 250uM+celecoxib 30uM) showed excellent inhibitory effect to the GBM, the LN229 and LN18, which were the TMZ resistant GBM cell lines. Our data suggest that the combination therapy may inhibits cell proliferation, increases apoptosis, and increases the autophagy on LN229 and LN18. The potential molecular mechanisms were related to mitochondrial metabolism and respiratory chain inhibition.


Assuntos
Celecoxib/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Glioblastoma/tratamento farmacológico , Mitocôndrias/metabolismo , Temozolomida/uso terapêutico , Celecoxib/administração & dosagem , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Quimioterapia Combinada , Humanos , Mitocôndrias/efeitos dos fármacos , Oxirredução , Fosforilação , Temozolomida/administração & dosagem
20.
Sci Rep ; 10(1): 4653, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170277

RESUMO

Adaptive of trees and its correlation with the climatic are causing changes in tree species performance and distribution, which will change breeding programs and influence forest productivity. To further evaluate the joint influence of climatic factors and provenance on the ring width (RW) and ring density (RD) of Masson pine. We selected 18 provenances at Chun'an (CA) and Taizi Mountain (TZS) test site, which representing four different breeding regions, including the south, west, north and east-central regions. The results showed that the provenance effects were significantly for the RW and RD. The provenances from high temperature and low latitude regions had greater mean RW compared to species from local and cold sources. The geographical genetic variation in wood traits is generally weak. The correlation between RW of Masson pine and precipitation was stronger in the relatively arid TZS site compared with that in relatively wet CA site, as well as the effect of temperature and precipitation on RD was earlier than that in CA test site. The response relationship between establishing the width of tree rings and the environmental variables of provenance indicated that during the transition from the northern and western breeding regions to the eastern and southern breeding regions, the response of RW to climate factors changed from being temperature-based to being precipitation-based. In addition, the response of provenance to the climate of seed sources origin showed their own variation characteristics in each breeding area. Therefore, genetic improvement of big diameter wood and wood density can be gain through selection of provenance and analysis of adaptability.


Assuntos
Adaptação Biológica , Pinus/crescimento & desenvolvimento , Locos de Características Quantitativas , China , Clima , Evolução Molecular , Pinus/genética , Melhoramento Vegetal
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