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1.
J Am Chem Soc ; 146(15): 10274-10280, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38568080

RESUMEN

The construction of C(sp3)-C(sp3) bonds remains one of the most difficult challenges in cross-coupling chemistry. Here, we report a photoredox/nickel dual catalytic approach that enables the simultaneous formation of two C(sp3)-C(sp3) linkages via trimolecular cross-coupling of alkenes with alkyl halides and hypervalent iodine-based reagents. The reaction harnesses a bimolecular homolytic substitution (SH2) mechanism and chemoselective halogen-atom transfer (XAT) to orchestrate the regioselective addition of electrophilic and nucleophilic alkyl radicals across unactivated alkenes without the need for a directing auxiliary. Utility is highlighted through late-stage (fluoro)alkylation and (trideutero)methylation of C═C bonds bearing different substitution patterns, offering straightforward access to drug-like molecules comprising sp3-hybridized carbon scaffolds.

2.
Small ; : e2405187, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39206605

RESUMEN

Traditional PEO electrolyte has high crystallinity which hinders the transmission of Li+, resulting in poor ion conductivity and complicated processing technology. Herein, a polymer electrolyte (p-electrolyte) with a wide electrochemical window and high ionic conductivity is designed, which possesses an amorphous condensed structure. The amorphous structure provides fast transport channels for Li+, so the p-electrolyte possesses an electrochemical window of 4.2 V, and high ionic conductivity of 1.58 × 10-5 S cm-1 at room temperature, which is 1-2 orders of magnitude higher than that of traditional PEO electrolyte. By using the designed polymer electrolyte as the foundation, an in situ curable composite polymer electrolyte (CPE-L) with multiple Li+ transport channels is elaborately constructed. The Cu-BTC MOF stores abundant Li+, which is introduced into the p-electrolyte. The rich unsaturated Cu2+ coordination sites of Cu-BTC can anchor TFSI- to release Li+, and the pore structure of Cu-BTC MOF cooperates with LLZTO nanoparticles to provide multiple fast transport channel for Li+, resulting in remarkable ionic conductivity (1.02 × 10-3 S cm-1) and Li+ transference number (0.58). The Li||CPE-L||Li symmetric battery cycles stably for more than 700 h at 0.1 mA cm-2, while the specific capacity of full battery is ≈153 mAh g-1 (RT, 0.2 C).

3.
Pharm Res ; 40(1): 145-156, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36002611

RESUMEN

PURPOSE: Hepatitis B virus (HBV) infection is such a global health problem that hundreds of millions of people are HBV carriers. Current anti-viral agents can inhibit HBV replication, but can hardly eradicate HBV. Cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (ODNs) are an adjuvant that can activate plasmacytoid dendritic cells (pDCs) and conventional dendritic cells (cDCs) to induce therapeutic immunity for HBV eradication. However, efficient delivery of CpG ODNs into pDCs and cDCs remains a challenge. In this study, we constructed a series of cationic lipid-assisted nanoparticles (CLANs) using different cationic lipids to screen an optimal nanoparticle for delivering CpG ODNs into pDCs and cDCs. METHODS: We constructed different CLANCpG using six cationic lipids and analyzed the cellular uptake of different CLANCpG by pDCs and cDCs in vitro and in vivo, and further analyzed the efficiency of different CLANCpG for activating pDCs and cDCs in both wild type mice and HBV-carrier mice. RESULTS: We found that CLAN fabricated with 1,2-Dioleoyl-3-trimethylammonium propane (DOTAP) showed the highest efficiency for delivering CpG ODNs into pDCs and cDCs, resulting in strong therapeutic immunity in HBV-carrier mice. By using CLANCpG as an immune adjuvant in combination with the injection of recombinant hepatitis B surface antigen (rHBsAg), HBV was successfully eradicated and the chronic liver inflammation in HBV-carrier mice was reduced. CONCLUSION: We screened an optimized CLAN fabricated with DOTAP for efficient delivery of CpG ODNs to pDCs and cDCs, which can act as a therapeutic vaccine adjuvant for treating HBV infection.


Asunto(s)
Hepatitis B , Nanopartículas , Ratones , Animales , Virus de la Hepatitis B , Oligodesoxirribonucleótidos/farmacología , Fosfatos , Citosina , Guanosina , Hepatitis B/tratamiento farmacológico , Ácidos Grasos Monoinsaturados , Adyuvantes Inmunológicos/uso terapéutico , Células Dendríticas
4.
Inorg Chem ; 62(16): 6314-6322, 2023 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-37043328

RESUMEN

The neutral (NN)-B-B-B-(N2) complex has been trapped in low-temperature dinitrogen matrix and identified by isotopic substitution and theoretical frequency calculations. The linear B-B-B skeleton is stabilized by two inequivalent N2, namely, one end-on and other side-on N2. The structure of linear B-B-B skeleton illustrates much difference from previously reported triangle configuration of B3 clusters. Frontier orbital analysis demonstrates that the σ orbital of end-on NN and the π-bonding orbital of side-on N2 acts as the donor orbital. π bonding character across B-B-B skeleton donates to the antibonding π* orbital of end-on NN and out of phase the B-B-B features π back-donation to antibonding π* orbital of side-on N2. The combination of strong σ-donating capacity coupled with a greater ability for accepting π-back-donation of the N2 ligand leads to the formation of (NN)-B-B-B-(N2) complex with linear B-B-B skeleton. In addition, complexes of (NN)B(NN), (NN)BB(NN), and (NN)B4(NN) have been identified in our experiments.

5.
Molecules ; 29(1)2023 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-38202759

RESUMEN

Laser ablated Be atoms have been reacted with acetonitrile molecules in 4 K solid neon matrix. The diberyllium products BeBeNCCH3 and CNBeBeCH3 have been identified by D and 13C isotopic substitutions and quantum chemical calculations. The stabilization of the diberyllium species is rationalized from the formation of the real Be-Be single bonds with bond distances as 2.077 and 2.058 Å and binding energies as -27.1 and -77.2 kcal/mol calculated at CCSD (T)/aug-cc-pVTZ level of theory for BeBeNCCH3 and CNBeBeCH3, respectively. EDA-NOCV analysis described the interaction between Be2 and NC···CH3 fragments as Lewis "acid-base" interactions. In the complexes, the Be2 moiety carries positive charges which transfer from antibonding orbital of Be2 to the bonding fragments significantly strengthen the Be-Be bonds that are corroborated by AIM, LOL and NBO analyses. In addition, mono beryllium products BeNCCH3, CNBeCH3, HBeCH2CN and HBeNCCH2 have also been observed in our experiments.

6.
Angew Chem Int Ed Engl ; 62(15): e202214633, 2023 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-36416716

RESUMEN

Herein, we report a Cu-mediated trifluoromethylation of carbonyl-type compounds and unactivated olefins enabled by visible-light irradiation via σ C(sp3 )-C bond-functionalization. The reaction is distinguished by its modularity, mild conditions and wide scope-even in the context of late-stage functionalization-thus offering a complementary approach en route to valuable C(sp3 )-CF3 architectures from easily accessible precursors.

7.
Inorg Chem ; 60(23): 17649-17656, 2021 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-34747602

RESUMEN

The reactions of laser-ablated Ce, Sm, Eu, and Lu atoms with acetonitrile were studied by matrix infrared spectra in a neon matrix, and M←NCCH3, M-η2-(NC)-CH3, and CN-M-CH3 were identified with isotopic substitution and quantum chemical calculations. The major product is the insertion complex (CN-M-CH3), while the end-on and side-on complexes (M←NCCH3 and M-η2-(NC)-CH3) are also trapped in the matrix. The CCN antisymmetric stretching mode for Ce-η2-(NC)-CH3 was observed at 1536.9 cm-1, which is much lower than the same modes observed for other lanthanides. NBO analysis reveals that Ce exhibits a remarkable 4f-orbital contribution in bonding to N and to C, reconfirming an active 4f-orbital contribution of cerium in bonding in the side-on complex, while the 4f contributions of Sm and Eu to the M-N and M-C bonds are much lower and the 4f orbital of Lu is not involved in bonding.

8.
J Am Chem Soc ; 142(49): 20594-20599, 2020 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-33252234

RESUMEN

A dual platform for forging sp2-sp3 and sp3-sp3 carbon bonds via catalytic ß-scission of aliphatic alcohol derivatives with both aryl and alkyl halides is disclosed. This protocol is distinguished by its wide substrate scope and broad applicability, even in the context of late-stage functionalization.

9.
NMR Biomed ; 33(11): e4382, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32686241

RESUMEN

The subthalamic nucleus (STN) and globus pallidus internus (GPi) are commonly used targets in deep-brain stimulation (DBS) surgery for the treatment of movement disorders. The success of DBS critically depends on the spatial precision of stimulation. By taking advantage of good contrast between iron-rich deep-brain nuclei and surrounding tissues, quantitative susceptibility mapping (QSM) has shown promise in differentiating the STN and GPi from the adjacent substantia nigra and globus pallidus externus, respectively. Nonlinear morphology-enabled dipole inversion (NMEDI) is a widely used QSM algorithm, but the image quality of reconstructed susceptibility maps relies on the regularization parameter selection. To date, few studies have systematically optimized the regularization parameter at the ultra-high field of 7 T. In this study, we optimized the regularization parameter in NMEDI to improve the depiction of STN and GPi at different spatial resolutions at both 3 T and 7 T. The optimized QSM images were further compared with other susceptibility-based images, including T2*-weighted (T2*w), R2*, susceptibility-weighted, and phase images. QSM showed better depiction of deep-brain nuclei with clearer boundaries compared with the other methods, and 7 T QSM at 0.35 × 0.35 × 1.0 mm3 demonstrated superior performance to the others. Our findings suggest that optimized high-resolution QSM at 7 T allows for improved delineation of deep-brain nuclei with clear and sharp borders between nuclei, which may become a promising tool for DBS nucleus preoperative localization.


Asunto(s)
Mapeo Encefálico , Globo Pálido/diagnóstico por imagen , Núcleo Subtalámico/diagnóstico por imagen , Algoritmos , Medios de Contraste/química , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Relación Señal-Ruido , Adulto Joven
10.
Development ; 143(1): 35-44, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26586222

RESUMEN

The mechanism for the basal targeting of the Miranda (Mira) complex during the asymmetric division of Drosophila neuroblasts (NBs) is yet to be fully understood. We have identified conserved Phosphotyrosyl phosphatase activator (PTPA) as a novel mediator for the basal localization of the Mira complex in larval brain NBs. In mutant Ptpa NBs, Mira remains cytoplasmic during early mitosis and its basal localization is delayed until anaphase. Detailed analyses indicate that PTPA acts independent of and before aPKC to localize Mira. Mechanistically, our data show that the phosphorylation status of the T591 residue determines the subcellular localization of Mira and that PTPA facilitates the dephosphorylation of T591. Furthermore, PTPA associates with the Protein phosphatase 4 complex to mediate localization of Mira. On the basis of these results, a two-step process for the basal localization of Mira during NB division is revealed: cortical association of Mira mediated by the PTPA-PP4 complex is followed by apical aPKC-mediated basal restriction.


Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/embriología , Células-Madre Neurales/metabolismo , Neurogénesis/fisiología , Proteína Quinasa C/metabolismo , Animales , División Celular Asimétrica/fisiología , Línea Celular , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación
11.
Small ; 15(16): e1900055, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30884095

RESUMEN

Nucleic acid-based macromolecules have paved new avenues for the development of therapeutic interventions against a spectrum of diseases; however, their clinical translation is limited by successful delivery to the target site and cells. Therefore, numerous systems have been developed to overcome delivery challenges to nucleic acids. From the viewpoint of clinical translation, it is highly desirable to develop systems with clinically validated materials and controllability in synthesis. With this in mind, a cationic lipid assisted PEG-b-PLA nanoparticle (CLAN) is designed that is capable of protecting nucleic acids via encapsulation inside the aqueous core, and delivers them to target cells, while maintaining or improving nucleic acid function. The system is formulated from clinically validated components (PEG-b-PLA and its derivatives) and can be scaled-up for large scale manufacturing, offering potential for its future use in clinical applications. Here, the development and working mechanisms of CLANs, the ways to improve its delivery efficacy, and its application in various disease treatments are summarized. Finally, a prospective for the further development of CLAN is also discussed.


Asunto(s)
Lactatos/química , Nanomedicina/métodos , Nanopartículas/química , Neoplasias/terapia , Ácidos Nucleicos/uso terapéutico , Polietilenglicoles/química , Animales , Sistemas CRISPR-Cas , Edición Génica , Corazón/fisiología , Humanos , Sistema Inmunológico , Macrófagos del Hígado/metabolismo , Lípidos/química , Sustancias Macromoleculares , Neoplasias/metabolismo , Células Madre Neoplásicas/citología , Ácidos Nucleicos/química , Pez Cebra
12.
Proc Natl Acad Sci U S A ; 113(15): 4164-9, 2016 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-27035960

RESUMEN

A principal goal of cancer nanomedicine is to deliver therapeutics effectively to cancer cells within solid tumors. However, there are a series of biological barriers that impede nanomedicine from reaching target cells. Here, we report a stimuli-responsive clustered nanoparticle to systematically overcome these multiple barriers by sequentially responding to the endogenous attributes of the tumor microenvironment. The smart polymeric clustered nanoparticle (iCluster) has an initial size of ∼100 nm, which is favorable for long blood circulation and high propensity of extravasation through tumor vascular fenestrations. Once iCluster accumulates at tumor sites, the intrinsic tumor extracellular acidity would trigger the discharge of platinum prodrug-conjugated poly(amidoamine) dendrimers (diameter ∼5 nm). Such a structural alteration greatly facilitates tumor penetration and cell internalization of the therapeutics. The internalized dendrimer prodrugs are further reduced intracellularly to release cisplatin to kill cancer cells. The superior in vivo antitumor activities of iCluster are validated in varying intractable tumor models including poorly permeable pancreatic cancer, drug-resistant cancer, and metastatic cancer, demonstrating its versatility and broad applicability.


Asunto(s)
Antineoplásicos/uso terapéutico , Nanopartículas , Neoplasias/tratamiento farmacológico , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Apoptosis , Línea Celular Tumoral , Humanos , Metástasis de la Neoplasia , Neoplasias/patología , Esferoides Celulares
13.
J Magn Reson Imaging ; 48(1): 111-120, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29232026

RESUMEN

BACKGROUND: Arterial spin labeling (ASL) based-noncontrast-enhanced 4D MR angiography (NCE 4D MRA) shows potential in characterizing cerebrovascular hemodynamics in cerebrovascular disorders. Ultrahigh-field theoretically benefits ASL signal with increased inherent signal-to-noise ratio (SNR) and prolonged blood T1 , which may provide improved delineation of vasculature in 4D MRA. PURPOSE: To investigate the feasibility of NCE 4D MRA using 3D Cartesian trajectory and stack-of-stars (SOS) golden angle radial trajectory at 7T. STUDY TYPE: A prospective study. SUBJECTS: Six normal volunteers and eight patients with arteriovenous malformation (AVM). FIELD STRENGTH/SEQUENCE: NCE 4D MRA with Cartesian and radial trajectories were performed at 3T and 7T. ASSESSMENT: Subjective image quality of 4D MRA was evaluated using a 4-point scale by two experienced neuroradiologists. The characterization of AVM components with 4D MRA and DSA was also graded using the Spetzler-Martin grading scale. STATISTICAL TESTS: Cohen's kappa coefficient was calculated to evaluate the agreement between two readers within each 4D MRA technique (Cartesian and Radial). A Wilcoxon signed-rank test was performed to compare the subjective image quality scores of 4D MRA between Cartesian and radial trajectories, and between 7T and 3T, respectively. RESULTS: Good-to-excellent image quality was achieved in 4D MRA with both Cartesian (3.83 ± 0.41) and radial (3.42 ± 0.49) acquisitions in healthy volunteers at 7T. However, markedly reduced scan time was needed with radial acquisition. 4D MRA at 7T (3.31 ± 0.59) shows better delineation of AVM lesion features, especially the vein drainage, compared with that of 3T (2.83 ± 0.75), although no statistical significance was achieved (P = 0.180). DATA CONCLUSION: The feasibility of ASL based 4D MRA at 7T with Cartesian and SOS golden angle radial acquisition was demonstrated. The clinical evaluation of 4D MRA in AVMs between 3T and 7T suggested 7T 4D MRA images acquired with radial acquisition demonstrate excellent delineation of AVM features, especially the draining veins. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage 2 J. Magn. Reson. Imaging 2017.


Asunto(s)
Malformaciones Arteriovenosas Intracraneales/diagnóstico por imagen , Angiografía por Resonancia Magnética , Adulto , Arterias/diagnóstico por imagen , Circulación Cerebrovascular , Simulación por Computador , Medios de Contraste , Estudios de Factibilidad , Femenino , Hemodinámica , Humanos , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Masculino , Relación Señal-Ruido , Marcadores de Spin , Adulto Joven
14.
Eur Radiol ; 28(9): 3882-3892, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-29532240

RESUMEN

OBJECTIVES: To image the pedunculopontine tegmental nucleus (PPN), a deep brain stimulation (DBS) target for Parkinson disease, using MRI with validated results. METHODS: This study used the MP2RAGE sequence with high resolution and enhanced grey-white matter contrast on a 7-T ultra-high-field MRI system to image the PPN as well as a diffusion spectrum imaging method on a 3-T MRI system to reconstruct the main fibre systems surrounding the PPN. The coordinates of the rostral and caudal PPN poles of both sides were measured in relation to the third and fourth ventricular landmarks on the 7-T image. RESULTS: The boundary of the PPN was delineated, and showed morphology consistent with previous histological works. The main fibres around the PPN were reconstructed. The pole coordinate results combined with the fibre spatial relationships validate the imaging results. CONCLUSIONS: A practical protocol is provided to directly localise the PPN using MRI; the position and morphology of the PPN can be obtained and validated by locating its poles relative to two ventricular landmarks and by inspecting its spatial relationship with the surrounding fibre systems. This technique can be potentially used in clinics to define the boundary of the PPN before DBS surgery for treatment of Parkinson disease in a more precise and reliable manner. KEY POINTS: • Combined information helps localise the PPN as a DBS target for PD patients • Scan the PPN at 7 T and measure its coordinates against different ventricular landmarks • Reconstruct the main fibres around the PPN using diffusion spectrum imaging.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Núcleo Tegmental Pedunculopontino/diagnóstico por imagen , Estimulación Encefálica Profunda , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/patología , Adulto Joven
15.
Neuroradiology ; 60(8): 785-794, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29869697

RESUMEN

PURPOSE: This study was conducted to determine the benefit of magnetic resonance imaging (MRI) at 7 T in detecting structural lesions and previously unidentified abnormalities in patients with tuberous sclerosis complex (TSC). METHODS: Thirteen patients with TSC (8-36 years, seven males) previously diagnosed by 3 T MRI underwent additional imaging at 7 T, which included T1-weighted magnetization-prepared rapid gradient-echo (MPRAGE), T2-weighted turbo spin echo (TSE), SPACE fluid attenuated inversion recovery (FLAIR), susceptibility weighted imaging (SWI), white matter suppressed (WM-suppressed), and gray-white matter tissue border enhancement (GW-TBE) MPRAGE sequences. Subtle lesions, tuberal morphology, and perituberal cortex abnormalities were examined and compared to those observed at 3 T MRI using standard sequences. RESULTS: Improved visualization of TSC lesions was achieved in all subjects at 7 T compared to 3 T imaging, and three subjects received resective surgery. The 7 T T1- and T2-weighted images had high spatial resolution and provided a clear delineation of the perituberal cortex. SWI revealed abnormal blood vessel morphology. WM-suppressed and GW-TBE protocols, adjusted specifically for TSC imaging, aided in visualizing lesions and uncovered more extensive subtle lesions and abnormalities beyond the conventionally detected tubers. CONCLUSIONS: Due to its high spatial resolution and powerful new imaging protocols, 7 T MRI provided a better evaluation of subtle lesions and perituberal details compared with conventional MRI at 3 T, with potential implications for diagnosis and operative treatment of TSC and its related epilepsy.


Asunto(s)
Epilepsia/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Esclerosis Tuberosa/diagnóstico por imagen , Adolescente , Adulto , Niño , Electroencefalografía , Epilepsia/complicaciones , Epilepsia/cirugía , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Imagenología Tridimensional , Masculino , Esclerosis Tuberosa/complicaciones , Esclerosis Tuberosa/cirugía
16.
Angew Chem Int Ed Engl ; 55(3): 1010-4, 2016 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-26756443

RESUMEN

Successful bench-to-bedside translation of nanomedicine relies heavily on the development of nanocarriers with superior therapeutic efficacy and high biocompatibility. However, the optimal strategy for improving one aspect often conflicts with the other. Herein, we report a tactic of designing tumor-pH-labile linkage-bridged copolymers of clinically validated poly(D,L-lactide) and poly(ethylene glycol) (PEG-Dlink(m)-PDLLA) for safe and effective drug delivery. Upon arriving at the tumor site, PEG-Dlink(m)-PDLLA nanoparticles will lose the PEG layer and increase zeta potential by responding to tumor acidity, which significantly enhances cellular uptake and improves the in vivo tumor inhibition rate to 78.1% in comparison to 47.8% of the non-responsive control. Furthermore, PEG-Dlink(m)-PDLLA nanoparticles show comparable biocompatibility with the clinically used PEG-b-PDLLA micelle. The improved therapeutic efficacy and safety demonstrate great promise for our strategy in future translational studies.


Asunto(s)
Antineoplásicos/uso terapéutico , Concentración de Iones de Hidrógeno , Neoplasias/tratamiento farmacológico , Polímeros/química , Antineoplásicos/administración & dosificación , Línea Celular Tumoral , Humanos , Nanopartículas , Neoplasias/química
17.
J Am Chem Soc ; 137(48): 15217-24, 2015 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-26571079

RESUMEN

Although surface PEGylation of siRNA vectors is effective for preventing protein adsorption and thereby helps these vectors to evade the reticuloendothelial system (RES) in vivo, it also suppresses the cellular uptake of these vectors by target cells. This dilemma could be overcome by employing stimuli-responsive shell-detachable nanovectors to achieve enhanced cellular internalization while maintaining prolonged blood circulation. Among the possible stimuli, dysregulated pH in tumor (pHe) is the most universal and practical. However, the design of pHe-sensitive system is problematic because of the subtle differences between the pHe and pH in other tissues. Here, a simple acid-sensitive bridged copolymer is developed and used for tumor-targeted systemic delivery of siRNA. After forming the micelleplex delivery system, the corresponding nanoparticles (Dm-NP) might undergo several modifications as follows: (i) a poly(ethylene glycol) (PEG) corona, which is stable in the circulatory system and protects nanovectors from RES clearance; (ii) a pHe responsive linkage breakage, which induces PEG detachment at tumor sites and thereby facilitates cell targeting; and (iii) a cell-penetration peptide, which is exposed upon the removal of PEG and further enhances cellular uptake. Thus, Dm-NP achieved both prolonged circulation and effective accumulation in tumor cells and resulted in the safe and enhanced inhibition of non-small cell lung cancer growth.


Asunto(s)
Neoplasias/metabolismo , Polímeros/química , ARN Interferente Pequeño/administración & dosificación , Micelas , ARN Interferente Pequeño/farmacocinética , Distribución Tisular
18.
Nat Commun ; 15(1): 3848, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38719794

RESUMEN

Fixation and functionalisation of N2 by main-group elements has remained scarce. Herein, we report a fixation and cleavage of the N ≡ N triple bond achieved in a dinitrogen (N2) matrix by the reaction of hydrogen and laser-ablated silicon atoms. The four-membered heterocycle H2Si(µ-N)2SiH2, the H2SiNN(H2) and HNSiNH complexes are characterized by infrared spectroscopy in conjunction with quantum-chemical calculations. The synergistic interaction of the two SiH2 moieties with N2 results in the formation of final product H2Si(µ-N)2SiH2, and theoretical calculations reveal the donation of electron density of Si to π* antibonding orbitals and the removal of electron density from the π bonding orbitals of N2, leading to cleave the non-polar and strong NN triple bond.

19.
Sci Bull (Beijing) ; 69(3): 354-366, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38072706

RESUMEN

Engineered T cells expressing chimeric antigen receptor (CAR) exhibit high response rates in B-cell malignancy treatments and possess therapeutic potentials against various diseases. However, the complicated ex vivo production process of CAR-T cells limits their application. Herein, we use virus-mimetic fusogenic nanovesicles (FuNVs) to produce CAR-T cells in vivo via membrane fusion-mediated CAR protein delivery. Briefly, the FuNVs are modified using T-cell fusogen, adapted from measles virus or reovirus fusogens via displaying anti-CD3 single-chain variable fragment. The FuNVs can efficiently fuse with the T-cell membrane in vivo, thereby delivering the loaded anti-CD19 (αCD19) CAR protein onto T-cells to produce αCD19 CAR-T cells. These αCD19 CAR-T cells alone or in combination with anti-OX40 antibodies can treat B-cell lymphoma without inducing cytokine release syndrome. Thus, our strategy provides a novel method for engineering T cells into CAR-T cells in vivo and can further be employed to deliver other therapeutic membrane proteins.


Asunto(s)
Linfoma de Células B , Receptores Quiméricos de Antígenos , Humanos , Receptores de Antígenos de Linfocitos T/genética , Linfocitos T , Receptores Quiméricos de Antígenos/genética , Antígenos CD19
20.
Int J Biol Macromol ; 258(Pt 1): 128799, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38110165

RESUMEN

Using a solvent-free radical grafting technique, glycidyl methacrylate (GMA) and maleic anhydride (MAH) were used as functionalized graft monomers, styrene (St) as a copolymer monomer, and grafted onto polylactic acid (PLA). A series of PLA-g-(GMA/MAH-co-St) graft copolymers were prepared by adjusting the GMA/MAH ratio. Subsequently, the prepared graft copolymers were used as a compatibilizer with PLA and polypropylene carbonate (PPC) for melt blending to prepare PLA/PPC/PLA-g-(GMA/MAH-co-St) blends. The effects of changes in the GMA/MAH ratio in the graft copolymer on the thermodynamics, rheology, optics, degradation performance, mechanical properties, and microstructure of the blend were studied. The results found that GMA, MAH, and St were successfully grafted onto PLA, and the PLA-g-(GMA/MAH-co-St) graft copolymer obtained from the reaction had a good toughening effect on the PLA/PPC blend system, which significantly improved the mechanical properties of the PLA/PPC/PLA-g-(GMA/MAH-co-St) blend without reducing its degradation performance, resulting in a biodegradable blend material with excellent comprehensive performance. In the PLA-g-(GMA/MAH-co-St) grafting reaction system, when GMA/MAH = 1.5/1.5 (w/w), the grafting degree of the graft copolymer increased most significantly, from 0.83 phr to 1.51 phr. This composition of graft copolymer can effectively improve the compatibility between PLA and PPC. The resulting PLA/PPC blend can maintain good melt flow properties (MFR of 14.51 g/10 min), high transparency, and low haze (light transmittance of 91.56 %, haze of 20.5 %), while significantly improving its thermal stability (T95%, Tmax, and Et increased by 12.87 °C, 20.33 °C, and 32.00 kJ/mol, respectively). Moreover, when introducing PLA-g-(GMA/MAH-co-St) (GMA/MAH = 1.5/1.5 (wt/wt)) graft copolymer into the system, the toughness of the PLA/PPC/PLA-g-(GMA/MAH-co-St) blend system is optimal, with the notch impact strength and fracture elongation increasing to 184.6 % and 535.4 % of the PLA/PPC blend, respectively, at which point the fracture surface of the impact sample shows a wrinkled fracture feature indicative of toughness.


Asunto(s)
Compuestos Epoxi , Metacrilatos , Poliésteres , Polímeros , Poliésteres/química , Polímeros/química , Polipropilenos , Anhídridos Maleicos , Estireno
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