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2.
Nat Commun ; 15(1): 3305, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632270

RESUMO

Poaceae members shared a whole-genome duplication called rho. However, little is known about the evolutionary pattern of the rho-derived duplicates among Poaceae lineages and implications in adaptive evolution. Here we present phylogenomic/phylotranscriptomic analyses of 363 grasses covering all 12 subfamilies and report nine previously unknown whole-genome duplications. Furthermore, duplications from a single whole-genome duplication were mapped to multiple nodes on the species phylogeny; a whole-genome duplication was likely shared by woody bamboos with possible gene flow from herbaceous bamboos; and recent paralogues of a tetraploid Oryza are implicated in tolerance of seawater submergence. Moreover, rho duplicates showing differential retention among subfamilies include those with functions in environmental adaptations or morphogenesis, including ACOT for aquatic environments (Oryzoideae), CK2ß for cold responses (Pooideae), SPIRAL1 for rapid cell elongation (Bambusoideae), and PAI1 for drought/cold responses (Panicoideae). This study presents a Poaceae whole-genome duplication profile with evidence for multiple evolutionary mechanisms that contribute to gene retention and losses.


Assuntos
Oryza , Poaceae , Filogenia , Duplicação Gênica , Oryza/genética , Genoma de Planta , Evolução Molecular
3.
J Med Virol ; 96(3): e29515, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38469923

RESUMO

Hepatitis B virus (HBV) infection significantly impacts Asian populations. The influences of continuous HBV antigen and inflammatory stimulation to T cells in chronic hepatitis B (CHB) remain unclear. In this study, we first conducted bioinformatics analysis to assess T-cell signaling pathways in CHB patients. In a Taiwanese cohort, we examined the phenotypic features of HBVcore -specific T cells and their correlation with clinical parameters. We used core protein overlapping peptides from the Taiwan prevalent genotype B HBV to investigate the antiviral response and the functional implication of HBV-specific T cells. In line with Taiwanese dominant HLA-alleles, we also evaluated ex vivo HBVcore -specific T cells by pMHC-tetramers targeting epitopes within HBV core protein. Compared to healthy subjects, we disclosed CD8 T cells from CHB patients had higher activation marker CD38 levels but showed an upregulation in the inhibitory receptor PD-1. Our parallel study showed HBV-specific CD8 T cells were more activated with greater PD-1 expression than CMV-specific subset and bulk CD8 T cells. Moreover, our longitudinal study demonstrated a correlation between the PD-1 fluctuation pattern of HBVcore -specific CD8 T cells and liver inflammation in CHB patients. Our research reveals the HBV core antigen-mediated immunopathologic profile of CD8 T cells in chronic HBV infection. Our findings suggest the PD-1 levels of HBVcore -specific CD8 T cells can be used as a valuable indicator of personal immune response for clinical application in hepatitis management.


Assuntos
Hepatite B Crônica , Hepatite B , Humanos , Vírus da Hepatite B/genética , Receptor de Morte Celular Programada 1/genética , Estudos Longitudinais , Antígenos do Núcleo do Vírus da Hepatite B , Linfócitos T CD8-Positivos
4.
Glob Chang Biol ; 30(2): e17199, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38385944

RESUMO

Denitrification plays a critical role in soil nitrogen (N) cycling, affecting N availability in agroecosystems. However, the challenges in direct measurement of denitrification products (NO, N2 O, and N2 ) hinder our understanding of denitrification N losses patterns across the spatial scale. To address this gap, we constructed a data-model fusion method to map the county-scale denitrification N losses from China's rice fields over the past decade. The estimated denitrification N losses as a percentage of N application from 2009 to 2018 were 11.8 ± 4.0% for single rice, 12.4 ± 3.7% for early rice, and 11.6 ± 3.1% for late rice. The model results showed that the spatial heterogeneity of denitrification N losses is primarily driven by edaphic and climatic factors rather than by management practices. In particular, diffusion and production rates emerged as key contributors to the variation of denitrification N losses. These findings humanize a 38.9 ± 4.8 kg N ha-1 N loss by denitrification and challenge the common hypothesis that substrate availability drives the pattern of N losses by denitrification in rice fields.


Assuntos
Oryza , Desnitrificação , Projetos de Pesquisa , Nitrogênio , China
5.
Appl Opt ; 63(2): 327-337, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38227225

RESUMO

Source mask optimization (SMO) is a widely used computational lithography technique for compensating lithographic distortion. However, line-end shortening is still a key factor that cannot be easily corrected and affects the image fidelity of lithography at advanced nodes. This paper proposes a source mask optimization method that suppresses line-end shortening and improves lithography fidelity. An adaptive hybrid weight method is employed to increase the weights of the line end during the optimization, which adaptively updates the weights in each iteration according to the edge placement error (EPE). A cost function containing a penalty term based on the normalized image log slope (NILS) is established to ensure the fidelity of the overall feature when paying more attention to the line-end region. The scope of this penalty term is regulated by widening and extending the split contour to further reduce the line-end shortening. Simulation results show that the proposed method can effectively suppress the line-end shortening and improve the lithography fidelity compared with the traditional SMO method.

6.
J Mater Chem B ; 12(5): 1361-1371, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38234194

RESUMO

Implantable electrodes have raised great interest over the last years with the increasing incidence of neurodegenerative disorders. For brain implant devices, some key factors resulting in the formation of glial scars, such as mechanical mismatch and acute injury-induced inflammation, should be considered for material design. Therefore, in this study, a new biocompatible flexible electrode (e-SgG) with arbitrary shapes on a positive electrode was developed via electrogelation by applying a direct electrical voltage on a silk fibroin/gelatin/reduced graphene oxide composite hydrogel. The implantable flexible e-SgG-2 film with 1.23% rGO content showed high Young's modulus (11-150 MPa), which was sufficient for penetration under dried conditions but subsequently became a biomimetic brain tissue with low Young's modulus (50-3200 kPa) after insertion in the brain. At the same time, an anti-inflammatory drug (DEX) incorporated into the e-SgG-2 film can be electrically stimulated to exhibit two-stage release to overcome tissue inflammation during cyclic voltammetry via degradation by applying an AC field. The results of cell response to the SF/gelatin/rGO/DEX composite film showed that the released DEX could interrupt astrocyte growth to reduce the inflammatory response but showed non-toxicity toward neurons, which demonstrated a great potential for the application of the biocompatible and degradable e-SgG-D electrodes in the improvement of nerve tissue repair.


Assuntos
Gelatina , Seda , Humanos , Eletrodos Implantados , Encéfalo , Inflamação , Anti-Inflamatórios
7.
Artigo em Inglês | MEDLINE | ID: mdl-37498753

RESUMO

OBJECTIVE: A brain-computer interface (BCI) can be used to translate neuronal activity into commands to control external devices. However, using noninvasive BCI to control a robotic arm for movements in three-dimensional (3D) environments and accomplish complicated daily tasks, such as grasping and drinking, remains a challenge. APPROACH: In this study, a shared robotic arm control system based on hybrid asynchronous BCI and computer vision was presented. The BCI model, which combines steady-state visual evoked potentials (SSVEPs) and blink-related electrooculography (EOG) signals, allows users to freely choose from fifteen commands in an asynchronous mode corresponding to robot actions in a 3D workspace and reach targets with a wide movement range, while computer vision can identify objects and assist a robotic arm in completing more precise tasks, such as grasping a target automatically. RESULTS: Ten subjects participated in the experiments and achieved an average accuracy of more than 92% and a high trajectory efficiency for robot movement. All subjects were able to perform the reach-grasp-drink tasks successfully using the proposed shared control method, with fewer error commands and shorter completion time than with direct BCI control. SIGNIFICANCE: Our results demonstrated the feasibility and efficiency of generating practical multidimensional control of an intuitive robotic arm by merging hybrid asynchronous BCI and computer vision-based recognition.


Assuntos
Interfaces Cérebro-Computador , Procedimentos Cirúrgicos Robóticos , Humanos , Potenciais Evocados Visuais , Movimento/fisiologia , Computadores , Eletroencefalografia/métodos
8.
Cancers (Basel) ; 15(10)2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37345023

RESUMO

BACKGROUND: Approximately 10-40% of hepatocellular carcinoma (HCC) patients have definite vascular invasion at the time of diagnosis. Without curative treatment options, these patients have an abysmal prognosis with a median survival of only a few months following systemic therapy. However, supportive evidence of combining multiple locoregional treatments with systemic therapy is limited. This study compared the outcomes of sorafenib alone versus multimodality therapy with sorafenib, radiotherapy (RT), and transarterial chemoembolization (TACE) in advanced HCC patients with macrovascular invasion (MaVI). METHODS: The process took place over a nine-year period between March 2009 and October 2017, wherein 78 HCC patients with MaVI who underwent either sorafenib therapy alone (n = 49) or combined sorafenib/RT/TACE (n = 29) therapy were chosen for the retrospective study. We compared the overall survival (OS) between the two groups using the Cox regression hazard model and adjusted imbalances using propensity score matching (PSM). RESULTS: At the last follow-up, 76 patients had died, with a median follow-up time of 4.8 months for all patients and 31 months for those who were alive. Patients treated with sorafenib/RT/TACE had superior OS compared to those treated with sorafenib alone, showing a median survival of 9.3 vs. 2.7 months and a one-year survival of 37.1% vs. 6.1% (p < 0.001). In the multivariable analysis, new diagnosis or recurrence of HCC and treatment modalities (sorafenib alone vs. sorafenib/RT/TACE) were independent prognostic factors for OS. Compared to patients treated with sorafenib alone, significantly better OS was further verified using PSM (p < 0.001) in patients who received multiple therapeutic modalities. CONCLUSION: Multimodality therapy with sorafenib/RT/TACE increased OS threefold versus sorafenib therapy alone in HCC patients with MaVI. This study offers promising benefits of combined locoregional and systemic therapy for advanced HCC in current patient management and prospective clinical trials.

9.
Chemistry ; 29(40): e202300991, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37143186

RESUMO

The preparation of diimidazolium salt HBDIM 1, a precursor for a di-NHCs ligand, from cheap and easily available agent hexabenzylhexaazaisowurtzitane (HBIW) is reported. Under basic conditions, HBDIM undergoes facile deprotonation to in situ generate CageCarbene, which could efficiently coordinate to transition-metals, such as, Au, Cu or Pd, to give the corresponding bimetallic complexes 2-4. These complexes were isolated and fully characterized, including X-ray diffraction of their single crystals. It was found that the steric hinderance of CageCarbene is similar to that of SIMes but smaller than that of IPr, and electronically, CageCarbene is a strong σ-donator similar to SIMes and a stronger σ-donator than IPr. Further studies showed that complexes 2-4 were highly reactive to catalyze up to 17 reactions. Control experiments utilizing a N-benzyl-substituted monoimidazolium salt showed much lower catalytic reactivity when it was bound to Au or Cu, but exhibited similar reactivity for the Pd complex. Kinetic studies showed that the low reactivity of the monodentate carbene-ligated Au or Cu complex was due to the low stability of the complex under the reaction conditions.

10.
Nat Food ; 4(5): 416-426, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37142747

RESUMO

Extreme climate events constitute a major risk to global food production. Among these, extreme rainfall is often dismissed from historical analyses and future projections, the impacts and mechanisms of which remain poorly understood. Here we used long-term nationwide observations and multi-level rainfall manipulative experiments to explore the magnitude and mechanisms of extreme rainfall impacts on rice yield in China. We find that rice yield reductions due to extreme rainfall were comparable to those induced by extreme heat over the last two decades, reaching 7.6 ± 0.9% (one standard error) according to nationwide observations and 8.1 ± 1.1% according to the crop model incorporating the mechanisms revealed from manipulative experiments. Extreme rainfall reduces rice yield mainly by limiting nitrogen availability for tillering that lowers per-area effective panicles and by exerting physical disturbance on pollination that declines per-panicle filled grains. Considering these mechanisms, we projected ~8% additional yield reduction due to extreme rainfall under warmer climate by the end of the century. These findings demonstrate that it is critical to account for extreme rainfall in food security assessments.


Assuntos
Oryza , Clima , China , Produtos Agrícolas , Mudança Climática
11.
Artigo em Inglês | MEDLINE | ID: mdl-37030734

RESUMO

A brain-computer interface (BCI) measures and analyzes brain activity and converts it into computer commands to control external devices. Traditional BCIs usually require full calibration, which is time-consuming and makes BCI systems inconvenient to use. In this study, we propose an online P300 BCI spelling system with zero or shortened calibration based on a convolutional neural network (CNN) and big electroencephalography (EEG) data. Specifically, three methods are proposed to train CNNs for the online detection of P300 potentials: (i) training a subject-independent CNN with data collected from 150 subjects; (ii) adapting the CNN online via a semisupervised learning/self-training method based on unlabeled data collected during the user's online operation; and (iii) fine-tuning the CNN with a transfer learning method based on a small quantity of labeled data collected before the user's online operation. Note that the calibration process is eliminated in the first two methods and dramatically shortened in the third method. Based on these methods, an online P300 spelling system is developed. Twenty subjects participated in our online experiments. Average accuracies of 89.38%, 94.00% and 93.50% were obtained by the subject-independent CNN, the self-training-based CNN and the transfer learning-based CNN, respectively. These results demonstrate the effectiveness of our methods, and thus, the convenience of the online P300-based BCI system is substantially improved.


Assuntos
Interfaces Cérebro-Computador , Humanos , Algoritmos , Calibragem , Potenciais Evocados P300 , Redes Neurais de Computação , Eletroencefalografia/métodos
12.
Angew Chem Int Ed Engl ; 62(24): e202302223, 2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37059692

RESUMO

1-Aryl-substituted bicyclo[1.1.1]pentanes (BCPs) are an important class of BCP derivatives with widespread application in drug development. Most syntheses of these materials require multiple chemical steps via BCP electrophiles or nucleophiles derived from [1.1.1]propellane. Although one-step, multicomponent radical cross-coupling reactions could provide a more sustainable and rapid route to access diverse heteroarylated BCPs, current approaches are limited to tertiary alkyl radicals, leading to a decrease in their practical value. In this study, a conceptually different approach enabled by a radical multicomponent heteroarylation of [1.1.1]propellane to access functionalized heteroarylated BCPs is described. Importantly, this protocol is compatible with primary-, secondary-, and tertiary aliphatic radicals, as well as various fluoroalkyl radical sources, thus enabling rapid library generation of sought-after BCP derivatives for drug development.

13.
J Am Chem Soc ; 145(9): 5363-5369, 2023 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-36802571

RESUMO

Over the past decade, bicyclo[1.1.1]pentane (BCP) motifs have come to the fore as valuable pharmaceutical bioisosteres of para-disubstituted benzenes. However, the limited approaches and requisite multistep syntheses of useful BCP building blocks are hampering early discovery research in medicinal chemistry. Herein we report the development of a modular strategy for the divergent preparation of functionalized BCP alkylamines. In this process, a general method to introduce fluoroalkyl groups to BCP scaffolds using readily available and easy-to-handle fluoroalkyl sulfinate salts was also developed. Moreover, this strategy can also be extended to S-centered radicals for incorporation of sulfones and thioethers into the BCP core. Overall, this multicomponent strategy enables rapid construction of BCP-type bioisosteres for applications in drug discovery.

14.
Transpl Immunol ; 77: 101747, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36436795

RESUMO

BACKGROUND: Osteoarthritis (OA) was a chronic degenerative joint disease. The dysregulation of circular RNAs (circRNAs) has been identified in OA progression. However, the function and regulation mechanism of circ_0114876 in OA remains largely unknown. METHOD: Firstly, we used LPS-treated C28/I2 cells as a cellular model of OA. Quantificational real-time polymerase chain reaction (qRT-PCR) was used to determine the expression levels of circ_0114876, miRNA-1227-3p, and ADAM10 in OA chondrocytes. Cell Counting Kit-8 (CCK8), 5-ethynyl-20-deoxyuridine (EdU) incorporation assays, flow cytometry, Enzyme-linked immunosorbent assay (ELISA) kit, and western blot were applied to confirm cell proliferation, apoptosis, inflammation, and extracellular matrix. of circ_0114876 in vitro. The interaction between circ_0114876 and its downstream target (miR-1227-3p) and mRNA target ADAM metallopeptidase domain 10 (ADAM10), was evaluated by luciferase assay and RNA immunoprecipitation (RIP) assay. RESULT: Circ_0114876 and ADAM10 were upregulated and miR-1227-3p was decreased in OA tissues and LPS-treated chondrocytes. Low expression of circ_0114876 promoted proliferation and inhibited apoptosis, inflammation, and extracellular matrix of the LPS-treated chondrocytes. Mechanistically, circ_0114876 functioned in human chondrocytes through targeting miR-1227-3p and ADAM10. Furthermore, miRNA-1227-3p inhibitor reversed the effect of circ_0114876 knockdown on the OA chondrocytes, and ADAM10 overexpression reversed the effect of miR-1227-3p mimic on the OA chondrocytes. CONCLUSION: Circ_0114876 was increased in OA tissues and cells. Circ_0114876 facilitated the progression in the LPS-induced OA cell model via regulating the miR-1227-3p/ADAM10 axis. This study would provide a potentially effective therapeutic strategy for OA progression.


Assuntos
MicroRNAs , Osteoartrite , Humanos , RNA Circular/genética , Lipopolissacarídeos , Osteoartrite/genética , Inflamação , Apoptose , MicroRNAs/genética , Proteína ADAM10/genética , Proteínas de Membrana/genética , Secretases da Proteína Precursora do Amiloide/genética
15.
J Anim Sci Biotechnol ; 13(1): 147, 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36461116

RESUMO

BACKGROUND: N6-methyladenosine (m6A) is an abundant post-transcriptional RNA modification that affects various biological processes. The fat mass and obesity-associated (FTO) protein, a demethylase encoded by the FTO gene, has been found to regulate adipocyte development in an m6A-dependent manner in multiple species. However, the effects of the m6A methylation and FTO demethylation functions on chicken adipogenesis remain unclear. This study aims to explore the association between m6A modification and chicken adipogenesis and the underlying mechanism by which FTO affects chicken preadipocyte development. RESULTS: The association between m6A modification and chicken lipogenesis was assessed by treating chicken preadipocytes with different doses of methyl donor betaine and methylation inhibitor cycloleucine. The results showed that betaine significantly increased methylation levels and inhibited lipogenesis, and the inverse effect was found in preadipocytes after cycloleucine treatment. Overexpression of FTO significantly inhibited m6A levels and promoted proliferation and differentiation of chicken preadipocytes. Silencing FTO showed opposite results. Mechanistically, FTO overexpression increased the expression of catenin beta 1 (CTNNB1) by improving RNA stability in an m6A-dependent manner, and we proved that FTO could directly target CTNNB1. Furthermore, CTNNB1 may be a positive regulator of adipogenesis in chicken preadipocytes. CONCLUSIONS: m6A methylation of RNA was negatively associated with adipogenesis of chicken preadipocytes. FTO could regulate CTNNB1 expression in a demethylation manner to promote lipogenesis.

16.
J Am Chem Soc ; 144(51): 23685-23690, 2022 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-36523116

RESUMO

The development of synthetic strategies for the preparation of bioisosteric compounds is a demanding undertaking in medicinal chemistry. Numerous strategies have been developed for the synthesis of bicyclo[1.1.1]pentanes (BCPs), bridge-substituted BCPs, and bicyclo[2.1.1]hexanes. However, progress on the synthesis of bicyclo[3.1.1]heptanes, which serve as meta-substituted arene bioisosteres, has not been previously explored. Herein, we disclose the first photoinduced [3σ + 2σ] cycloaddition for the synthesis of trisubstituted bicyclo[3.1.1]heptanes using bicyclo[1.1.0]butanes and cyclopropylamines. This transformation not only uses mild and operationally simple conditions but also provides unique meta-substituted arene bioisosteres. The applicability of this method is showcased by simple derivatization reactions.


Assuntos
Compostos Bicíclicos com Pontes , Heptanos , Compostos Bicíclicos com Pontes/química , Heptanos/química , Reação de Cicloadição , Hexanos/química , Butanos
17.
Chem Sci ; 13(40): 11936-11942, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36320918

RESUMO

Bicyclo[1.1.1]pentanes (BCPs), utilized as sp3-rich bioisosteres for tert-butyl- and aryl groups as well as internal alkynes, have gained considerable momentum in drug development programs. Although many elegant methods have been developed to access BCP amines and BCP aryls efficiently, the methods used to construct BCP ketones directly are relatively underdeveloped. In particular, the preparation of unsymmetrical 1,3-disubstituted-BCP ketones remains challenging and still requires multiple chemical steps. Herein, a single-step, multi-component approach to versatile disubstituted BCP ketones via nickel/photoredox catalysis is reported. Importantly, installing a boron group at the carbon position adjacent to the BCP structure bypasses the limitation to tertiary BF3K coupling partners, thus expanding the scope of this paradigm. Further transformation of disubstituted-BCP ketones into a variety of other BCP derivatives demonstrates the synthetic value of this developed method.

18.
ACS Biomater Sci Eng ; 8(11): 4807-4818, 2022 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-36222713

RESUMO

Multimodal neural interfaces include combined functions of electrical neuromodulation and synchronic monitoring of neurochemical and physiological signals in one device. The remarkable biocompatibility and electrochemical performance of polystyrene sulfonate-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) have made it the most recommended conductive polymer neural electrode material. However, PEDOT:PSS formed by electrochemical deposition, called PEDOT/PSS, often need multiple doping to improve structural instability in moisture, resolve the difficulties of functionalization, and overcome the poor cellular affinity. In this work, inspired by the catechol-derived adhesion and semiconductive properties of polydopamine melanin (PDAM), we used electrochemical oxidation polymerization to develop PDAM-doped PEDOT (PEDOT/PDAM) as a bioactive multimodal neural interface that permits robust electrochemical performance, structural stability, analyte-trapping capacity, and neural stem cell affinity. The use of potentiodynamic scans resolved the problem of copolymerizing 3,4-ethylenedioxythiophene (EDOT) and dopamine (DA), enabling the formation of PEDOT/PDAM self-assembled nanodomains with an ideal doping state associated with remarkable current storage and charge transfer capacity. Owing to the richness of hydrogen bond donors/acceptors provided by the hydroxyl groups of PDAM, PEDOT/PDAM presented better electrochemical and mechanical stability than PEDOT/PSS. It has also enabled high sensitivity and selectivity in the electrochemical detection of DA. Different from PEDOT/PSS, which inhibited the survival of human induced pluripotent stem cell-derived neural progenitor cells, PEDOT/PDAM maintained cell proliferation and even promoted cell differentiation into neuronal networks. Finally, PEDOT/PDAM was modified on a commercialized microelectrode array system, which resulted in the reduction of impedance by more than one order of magnitude; this significantly improved the resolution and reduced the noise of neuronal signal recording. With these advantages, PEDOT/PDAM is anticipated to be an efficient bioactive multimodal neural electrode material with potential application to brain-machine interfaces.


Assuntos
Células-Tronco Pluripotentes Induzidas , Humanos , Melaninas , Polímeros/farmacologia , Neurônios/fisiologia
19.
ACS Appl Mater Interfaces ; 14(41): 46188-46200, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36198117

RESUMO

Although numerous strategies have been implemented to develop nerve guidance conduits (NGCs) to treat peripheral nerve injury (PNI), functionalization of an NGC to make it remotely controllable for providing spatiotemporal modulation on in situ nerve tissues remains a challenge. In this study, a gelatin/silk (GS) hydrogel was used to develop an NGC based on its self-owned reversible thermoresponsive sol-to-gel phase transformation ability that permitted rapid three-dimensional (3D) micropatterning of the incorporated nerve growth factor (NGF)-loaded magnetic poly(lactic-co-glycolic acid) (PLGA) microcapsules (called NGF@MPs) via multiple magnetic guidance. The thermally controllable viscosity of GS enabled the rapid formation of a 3D gradient and linearly aligned distribution of NGF@MPs, leading to magnetically controlled 3D gradient release of NGF to enhance topographical nerve guidance and wound healing in PNIs. Particularly, the as-formed micropatterned hydrogel, called NGF@MPs-GS, showed corrugation topography with a pattern height H of 15 µm, which resulted in the linear axon alignment of more than 90% of cells. In addition, by an external magnetic field, spatiotemporal controllability of NGF release was obtained and permitted neurite elongation that was almost 2-fold longer than that in the group with external addition of NGF. Finally, an NGC prototype was fabricated and implanted into the injured sciatic nerve. The patterned implant, assisted by magnetic stimulation, demonstrated accelerated restoration of motor function within 14 days after implantation. It further contributed to the enhancement of axon outgrowth and remyelination after 28 days. This NGC, with controllable mechanical, biochemical, and topographical cues, is a promising platform for the enhancement of nerve regeneration.


Assuntos
Gelatina , Fator de Crescimento Neural , Fator de Crescimento Neural/farmacologia , Fator de Crescimento Neural/metabolismo , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Cápsulas , Preparações de Ação Retardada/farmacologia , Nervo Isquiático/lesões , Regeneração Nervosa , Hidrogéis/farmacologia , Seda , Fenômenos Magnéticos
20.
J Am Chem Soc ; 144(28): 12961-12969, 2022 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-35793500

RESUMO

Bicyclo[1.1.1]pentane (BCP) motifs as para-disubstituted aryl bioisosteres are playing an emerging role in pharmaceutical, agrochemical, and materials chemistry. The vast majority of these structures is obtained from a BCP electrophile or nucleophile, which are themselves derived from [1.1.1]propellane via cleavage of the internal C-C bond through the addition of either radicals or metal-based nucleophiles. Compared with the current stepwise approaches, a multicomponent reaction that provides direct access to complex and diverse disubstituted BCP products would be more attractive. Herein, we report a single-step, multicomponent approach to synthetically versatile arylated BCP products via nickel/photoredox catalysis. Importantly, this three-component process allows two C-C bonds to be formed in a single step and sets three quaternary centers, unprecedented in any previously reported methods. The method has been demonstrated to allow access to complex BCP architectures from aryl halide and radical precursor substrates.


Assuntos
Níquel , Catálise , Níquel/química , Oxirredução
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