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1.
Environ Monit Assess ; 196(2): 126, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38196071

RESUMEN

Forest soils serve as the greatest sink of terrestrial carbon (C) and have a significant impact on worldwide or regional C cycling. By reducing emissions and enhancing the C storage in forests, the environmental monitoring function of a forest ecosystem may be ensured. The study focused on measuring the densities of major nutrients in soil to gain insight into the C and nitrogen dynamics of the Himalayan sub-tropical forest ecosystem of India besides supplementing the information about the C storage potential of these forest soils. The study examined the physico-chemical properties and nutrient densities across three altitudinal ranges viz., 600-800 m (A1), 800-1000 m (A2) and 1000-1200 m (A3) and two aspects, i.e. Northern (N) and Southern (S) in a randomized complete block design and data collection was done from 24 main sample plots (3 altitudinal ranges × 2 aspects × 4 replications). The soil pH, electrical conductivity, and bulk density observed a decreasing pattern with an increase in altitude, whereas a reverse trend was observed in soil organic C (SOC), total nitrogen and available phosphorus. The SOC and total nitrogen densities ranged from 20.08 to 48.35 Mg ha-1 and 2.56 to 4.01 Mg ha-1, respectively in an increasing trend from A1 to A3. The northern aspect exhibited significantly higher SOC and nitrogen densities than the southern aspects. The C storage potential of forest soils followed the order A1 < A2 < A3 with significantly higher potential (nearly 1.5 times) compared to those on the southern aspect. There was a consistently significant increase in the C:N ratio (CNR) with a maximum value (10.51) at A3 and minimum value (8.37) at A1, however the effect of aspect remained insignificant. This research underscores the importance of considering altitude and aspect when planning forest restoration efforts, as these factors have a substantial influence on soil properties, C storage potential and CNR. Understanding the significance of CNR is critical, as it serves as a key indicator of greenhouse gas (GHG) emissions from forest soils. Ultimately, these findings empower policymakers and conservationists to make informed decisions that can contribute to the sustainable management of Himalayan forests and the global fight against climate change.


Asunto(s)
Cambio Climático , Ecosistema , Carbono , Monitoreo del Ambiente , Bosques , Nitrógeno , Suelo
2.
J Phys Chem B ; 127(37): 7946-7954, 2023 09 21.
Artículo en Inglés | MEDLINE | ID: mdl-37674349

RESUMEN

Biological membranes feature heterogeneous mixtures of lipids with different head and tail characteristics. Their biophysical properties are dictated by the intimate interaction among different constituent lipids. Previous studies suggest that the membrane area-per-lipid (APL) deviates from the linear rule of mixtures (LRM) for binary lipid membranes, but the underlying mechanism remains elusive. Our molecular dynamics (MD) simulations of binary lipid membranes consisting of lipids with different tail characteristics reveal a competitive mechanism whereby lipids tend to deform each other to minimize the hydrophobic mismatch between their tails. Depending on the relative tail lengths and saturation levels, this may result in an either positive or negative deviation of APL from the LRM. As lipid packing plays an essential role in membrane fusion and peptide-membrane binding, our findings may help guide the selection of lipids for the effective rational design of nanoliposomes and membrane-targeting peptides.


Asunto(s)
Fusión de Membrana , Lípidos de la Membrana , Membranas , Membrana Celular , Biofisica
3.
J Chem Inf Model ; 63(15): 4560-4573, 2023 08 14.
Artículo en Inglés | MEDLINE | ID: mdl-37432764

RESUMEN

The skew and shape of the molecular weight distribution (MWD) of polymers have a significant impact on polymer physical properties. Standard summary metrics statistically derived from the MWD only provide an incomplete picture of the polymer MWD. Machine learning (ML) methods coupled with high-throughput experimentation (HTE) could potentially allow for the prediction of the entire polymer MWD without information loss. In our work, we demonstrate a computer-controlled HTE platform that is able to run up to 8 unique variable conditions in parallel for the free radical polymerization of styrene. The segmented-flow HTE system was equipped with an inline Raman spectrometer and offline size exclusion chromatography (SEC) to obtain time-dependent conversion and MWD, respectively. Using ML forward models, we first predict monomer conversion, intrinsically learning varying polymerization kinetics that change for each experimental condition. In addition, we predict entire MWDs including the skew and shape as well as SHAP analysis to interpret the dependence on reagent concentrations and reaction time. We then used a transfer learning approach to use the data from our high-throughput flow reactor to predict batch polymerization MWDs with only three additional data points. Overall, we demonstrate that the combination of HTE and ML provides a high level of predictive accuracy in determining polymerization outcomes. Transfer learning can allow exploration outside existing parameter spaces efficiently, providing polymer chemists with the ability to target the synthesis of polymers with desired properties.


Asunto(s)
Polímeros , Peso Molecular , Polimerizacion , Polímeros/química
4.
Heliyon ; 9(5): e15841, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37159682

RESUMEN

Psychological and mental well-being has become a topic of concern worldwide after the hit of the COVID-19 pandemic. It has triggered enormous global health care vulnerabilities and resulted in full and partial lockdowns to prevent the new case. This research study provides a comprehensive overview of the published international scientific studies on the effect of COVID-19 on the psychological well-being of young adults. This study aims to review the top-cited authors, documents, journals, productive countries, the most used keywords, and trending themes in this area. Articles related to psychological well-being during the COVID-19 pandemic from January 2020 to December 2022 were extracted from the Scopus database with specified keywords. In total, 482 documents were retrieved as original articles and bibliometric analysis, thematic analysis and content analysis are performed and analyzed. The results show that the United States has contributed the largest publications followed by the United Kingdom and Italy. Through the cluster analysis, it is found that many articles have been published and considered the psychological and mental impact of COVID-19. Young adults from both developed and developing countries are majorly affected by the COVID-19 pandemic. The pandemic prioritizes the importance of global psychological well-being and health care. This study focused on different aspects, such as stress, resilience, and the mental health of young adults. The research findings of this study put forth the urgent need to provide preventive policies and intervention procedures to address the psychological health of young adults and proposed a conceptual framework.

5.
Micromachines (Basel) ; 14(5)2023 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-37241659

RESUMEN

The direct laser synthesis of periodically nanostructured 2D transition metal dichalcogenide (2D-TMD) films, from single source precursors, is presented here. Laser synthesis of MoS2 and WS2 tracks is achieved by localized thermal dissociation of Mo and W thiosalts, caused by the strong absorption of continuous wave (c.w.) visible laser radiation by the precursor film. Moreover, within a range of irradiation conditions we have observed occurrence of 1D and 2D spontaneous periodic modulation in the thickness of the laser-synthesized TMD films, which in some cases is so extreme that it results in the formation of isolated nanoribbons with a width of ~200 nm and a length of several micrometers. The formation of these nanostructures is attributed to the effect that is known as laser-induced periodic surface structures (LIPSS), which is caused by self-organized modulation of the incident laser intensity distribution due to optical feedback from surface roughness. We have fabricated two terminal photoconductive detectors based on nanostructured and continuous films and we show that the nanostructured TMD films exhibit enhanced photo-response, with photocurrent yield increased by three orders of magnitude as compared to their continuous counterparts.

6.
Exp Parasitol ; 243: 108407, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36349579

RESUMEN

The emergence of drug-resistant parasites and/or insecticide-resistant mosquito vectors necessitates developing alternative tools that either supplement or replace the conventional malaria control strategies. Trans-infecting the mosquito vector with symbionts that can either compete with a targeted pathogen or manipulate the host biology by reducing its vectorial capacity could be a promising and innovative biological approach for the control of infectious diseases This idea could be utilized to develop a novel and efficient vector control strategy; symbionts are dispersed into vector populations to reduce their ability to transmit human pathogens. Here, we reported the natural existence of Microsporidian (an obligate fungus) in the field-collected An. stephensi mosquito. However, laboratory-reared An. stephensi and An. culicifacies did not exhibit microsporidian infection. Similarly, 16s rRNA PCR identified ∼1kb amplicons in laboratory-reared An. stephensi and An. culicifacies, indicating the presence of naturally residing different bacterial species. DNA sequencing of these amplicons revealed the identities of different bacteria which are not well-characterized in terms of plasmodia-interaction activity in the Indian malaria vector. This article summarizes an overview of the previously studied microbial symbionts for their role in Plasmodium transmission along with a list of new or unexplored symbionts in the disease transmitting mosquito vectors. The summarized information could be utilized to explore such microbial symbionts for their role in Plasmodium-transmission biology in-depth and implementation in the malaria control interventions globally.


Asunto(s)
Anopheles , Insecticidas , Malaria , Animales , Humanos , Mosquitos Vectores , Anopheles/parasitología , Malaria/prevención & control , Malaria/parasitología , ARN Ribosómico 16S/genética , Bacterias
7.
Proc Natl Acad Sci U S A ; 118(43)2021 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-34663733

RESUMEN

We demonstrate how programmable shape evolution and deformation can be induced in plant-based natural materials through standard digital printing technologies. With nonallergenic pollen paper as the substrate material, we show how specific geometrical features and architectures can be custom designed through digital printing of patterns to modulate hygrophobicity, geometry, and complex shapes. These autonomously hygromorphing configurations can be "frozen" by postprocessing coatings to meet the needs of a wide spectrum of uses and applications. Through computational simulations involving the finite element method and accompanying experiments, we develop quantitative insights and a general framework for creating complex shapes in eco-friendly natural materials with potential sustainable applications for scalable manufacturing.


Asunto(s)
Papel , Tecnología , Simulación por Computador
8.
Pharmaceuticals (Basel) ; 14(7)2021 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-34358102

RESUMEN

The presence of small subpopulations of cells within tumor cells are known as cancer stem cells (CSCs). These cells have been the reason for metastasis, resistance with chemotherapy or radiotherapy, and tumor relapse in several types of cancers. CSCs underwent to epithelial-mesenchymal transition (EMT) and resulted in the development of aggressive tumors. CSCs have potential to modulate numerous signaling pathways including Wnt, Hh, and Notch, therefore increasing the stem-like characteristics of cancer cells. The raised expression of drug efflux pump and suppression of apoptosis has shown increased resistance with anti-cancer drugs. Among many agents which were shown to modulate these, the plant-derived bioactive agents appear to modulate these key regulators and were shown to remove CSCs. This review aims to comprehensively scrutinize the preclinical and clinical studies demonstrating the effects of phytocompounds on CSCs isolated from various tumors. Based on the available convincing literature from preclinical studies, with some clinical data, it is apparent that selective targeting of CSCs with plants, plant preparations, and plant-derived bioactive compounds, termed phytochemicals, may be a promising strategy for the treatment of relapsed cancers.

9.
Heliyon ; 5(3): e01346, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30923770

RESUMEN

Twenty inter-simple sequence repeat (ISSR) and twenty two start codon targeted (SCoT) primers were employed to analyze genetic diversity and population structure among 52 Trichosanthes dioica Roxb. accessions collected from nine different eco-geographical regions of India. ISSR markers proved to be more informative in genetic diversity assessment and produced higher mean number of polymorphic bands (15.25 with 95.96% polymorphism) and polymorphic information content (PIC) value (0.47) compared to SCoT markers (12.55 polymorphic bands with 92.20% polymorphism and PIC: 0.45). Total genetic diversity (Ht) and genetic diversity within populations (Hs) in T. dioica accessions was found to be very high (0.45 and 0.43, respectively). AMOVA analysis also revealed higher genetic variation within populations (81%) than among them (19%). Among different T. dioica populations, very low genetic differentiation (Gst: 0.05) and high gene flow (Nm: 9.32) were observed. T. dioica populations of Bihar state were found to be highly diverse and Kolkata and Cuttack populations were least diverse. T. dioica male plants were more variable than females. UPGMA, Neighbor-Joining and population structure analyses divided T. dioica populations into three main clusters. First cluster comprised of Meerut population, second cluster included of Cuttack and Kolkata populations and populations of Bihar, Delhi and Kanpur occurred in third cluster. Genetic diversity was found to be strongly positively correlated with the latitude and strongly negatively correlated with annual mean rainfall of different T. dioica cultivated regions. For sex identification, one SRAP primer combination, 'Em-6/Me-4' amplified two molecular markers of around 230 and 290 bp specific to male T. dioica plants of Bihar, Kanpur, North Delhi and Meerut populations and were completely absent from female plants.

10.
Mar Pollut Bull ; 128: 32-40, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29571379

RESUMEN

Biochar is carbonaceous mass that is produced from pyrolysis or gasification of biomass. It is so far majorly explored for soil remediation application, but recently it has attracted a lot of interest because of its unexplored applications in the area of adsorption. In this work, detailed study on biochars produced from two different feeds (rice husk and saw dust), at two different temperatures (450 and 550°C) and two different rates (fast and slow) of pyrolysis are discussed for oil spill mitigation. Biochar is characterized in detail by various techniques such as FTIR, 13C CPMAS, FESEM, RAMAN, TGA to determine the structural composition and observe the extent of pyrolysis. Tests to assess the performance of produced biochars as sorbents for oil spill mitigation have been demonstrated. The as produced biochars selectively absorbed crude oil from oil/water biphasic mixtures in various capacities.


Asunto(s)
Carbón Orgánico/química , Restauración y Remediación Ambiental/métodos , Contaminación por Petróleo/análisis , Petróleo/análisis , Contaminantes Químicos del Agua/análisis , Adsorción , Análisis Costo-Beneficio , Restauración y Remediación Ambiental/economía , Modelos Teóricos , Oryza/química , Tamaño de la Partícula , Propiedades de Superficie , Madera/química
11.
J Mater Chem B ; 5(41): 8254-8263, 2017 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-32264468

RESUMEN

Alginate based comb copolymers were synthesized by reversible addition-fragmentation chain transfer (RAFT). Alginate was used both in its supplied (213 kDa) and depolymerized (73 kDa) forms and prepared into a macroRAFT agent by solubility modification with tetrabutyl ammonium ions and functionalization with a RAFT agent on its hydroxyl moieties. Poly(oligo ethylene glycol methacrylate) (POEGMA) was then polymerized from the macroRAFT agents in organic solvent demonstrating pseudo first-order kinetics. The copolymers dissolved well in a range of organic solvents and demonstrated self-assembly into nanoparticles upon the introduction of calcium chloride in both aqueous and methanolic solutions with particle sizes ranging between 100 and 500 nm. Remarkable encapsulation efficiencies of 4-n-butylresorcinol, a lipophillic active pharmaceutical ingredient, were demonstrated in methanol, and a sustained release profile was observed over 6 hours in aqueous acidic media. These new materials complement a growing library of biodegradable and sustainable polymers that show notable potential for the use in encapsulation and drug delivery.

12.
Chem Commun (Camb) ; 52(64): 9897-900, 2016 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-27427407

RESUMEN

Polymer-grafted porous hollow silica nanoparticles prepared by reversible addition-fragmentation chain transfer polymerisation have an upper critical solution temperature of 45 °C. Conjugation of 5 nm gold nanoparticles onto polymer-grafted porous hollow silica nanoparticles enables remarkable specific photothermally-induced controlled release of encapsulated Rhodamine B by laser-stimulation at physiological temperature.

13.
Macromol Rapid Commun ; 36(23): 2102-6, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26379215

RESUMEN

A surfactant-free emulsion-based approach is developed for preparation of nanogels. A water-in-oil emulsion is generated feasibly from a mixture of water and a solution of disulfide-containing hyperbranched PEGylated poly(amido amine)s, poly(BAC2-AMPD1)-PEG, in chloroform. The water droplets in the emulsion are stabilized and filled with poly(BAC2-AMPD1)-PEG, and the crosslinked poly(amido amine)s nanogels are formed via the intermolecular disulfide exchange reaction. FITC-dextran is loaded within the nanogels by dissolving the compound in water before emulsification. Transmission electron microscopy and dynamic light scattering are applied to characterize the emulsion and the nanogels. The effects of the homogenization rate and the ratio of water/polymer are investigated. Redox-induced degradation and FITC-dextran release profile of the nanogels are monitored, and the results show efficient loading and redox-responsive release of FITC-dextran. This is a promising approach for the preparation of nanogels for drug delivery, especially for neutral charged carbohydrate-based drugs.


Asunto(s)
Cloroformo/química , Dextranos/química , Fluoresceína-5-Isotiocianato/análogos & derivados , Nanopartículas/química , Poliaminas/química , Agua/química , Emulsiones , Fluoresceína-5-Isotiocianato/química , Geles
14.
Biomater Sci ; 3(4): 597-607, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26222420

RESUMEN

Vinyl-terminated hyperbranched poly(amido amine)s is obtained by Michael addition polymerization of 4-(aminomethyl)piperidine (AMPD) with a double molar N,N-cystaminebis(acrylamide) (BAC). Then an amphiphilic hyperbranched poly(BAC2-AMPD1)-PEG is produced via converting the vinyl groups to amines followed by PEGylation. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and (1)H nuclear magnetic resonance (NMR) results indicate that the micelles can be obtained via self-assembly of hyperbranched poly(BAC2-AMPD1)-PEG. Further an anti-cancer drug, doxorubicin (DOX), can be loaded into the micelles. pH- and redox-response of the micelles of hyperbranched poly(BAC2-AMPD1)-PEG without and with DOX are investigated. The results of confocal microscopy and flow cytometry reflect that FITC tagged or DOX loaded micelles of hyperbranched poly(BAC2-AMPD1)-PEG can enter HepG2 and MCF-7 cells, and DOX can be observed in the nucleus of the cells. The cytotoxicity of the micelles without and with DOX is evaluated in HepG2 and MCF-7 cells, and the efficacy to kill the cancer cells is discussed in comparison with free DOX.


Asunto(s)
Acrilamidas/química , Antineoplásicos/química , Doxorrubicina/química , Sistemas de Liberación de Medicamentos/métodos , Metilaminas/química , Piperidinas/química , Poliaminas/química , Polietilenglicoles/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Humanos , Concentración de Iones de Hidrógeno , Micelas , Oxidación-Reducción , Polimerizacion
15.
Biologicals ; 43(5): 369-76, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26156404

RESUMEN

The prophylactic efficacies of plain and alum adsorbed lysate were evaluated by direct virulent challenge in mice model. A recently isolated brucellaphage 'ϕLd' was used for generation of lysates. Twenty four h incubated Brucella abortus S19 broth cultures standardized to contain approximately 10(8) CFU/ml were found suitable for generation of lysates. Three lysate batches produced through separate cycles did not show any significant variation with respect to protein and polysaccharide contents, endotoxin level and phage counts, indicating that compositionally stable lysate preparations can be generated through an optimized production process. Three polypeptides of ∼16, 19 and 23 kDa could be identified as immuno-dominant antigens of the lysate which induced both humoral and cell-mediated immune responses in a dose dependent manner. Results of efficacy evaluation trial confirmed dose-dependent protective potencies of lysate preparation. The lysate with an antigenic dose of 0.52 µg protein and 60 µg CHO adsorbed on aluminium gel (0.1 percent aluminium concentration) exhibited the highest protective potency which was greater than that induced by standard S19 vaccine. Phage lysate methodology provides a very viable option through which an improved immunizing preparation with all desirable traits can be developed against brucellosis, and integrated with immunization programmes in a more efficient manner.


Asunto(s)
Adyuvantes Inmunológicos/administración & dosificación , Hidróxido de Aluminio/administración & dosificación , Bacteriófagos , Brucella abortus/inmunología , Geles , Animales , Anticuerpos Antibacterianos/biosíntesis , Brucella abortus/patogenicidad , Brucella abortus/virología , Citocinas/metabolismo , Femenino , Inmunidad Celular , Ratones , Virulencia
16.
Meta Gene ; 5: 90-7, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26110116

RESUMEN

To detect genetic variations among different Simmondsia chinensis genotypes, two gene targeted markers, start codon targeted (SCoT) polymorphism and CAAT box-derived polymorphism (CBDP) were employed in terms of their informativeness and efficiency in analyzing genetic relationships among different genotypes. A total of 15 SCoT and 17 CBDP primers detected genetic polymorphism among 39 Jojoba genotypes (22 females and 17 males). Comparatively, CBDP markers proved to be more effective than SCoT markers in terms of percentage polymorphism as the former detecting an average of 53.4% and the latter as 49.4%. The Polymorphic information content (PIC) value and marker index (MI) of CBPD were 0.43 and 1.10, respectively which were higher than those of SCoT where the respective values of PIC and MI were 0.38 and 1.09. While comparing male and female genotype populations, the former showed higher variation in respect of polymorphic percentage and PIC, MI and Rp values over female populations. Nei's diversity (h) and Shannon index (I) were calculated for each genotype and found that the genotype "MS F" (in both markers) was highly diverse and genotypes "Q104 F" (SCoT) and "82-18 F" (CBDP) were least diverse among the female genotype populations. Among male genotypes, "32 M" (CBDP) and "MS M" (SCoT) revealed highest h and I values while "58-5 M" (both markers) was the least diverse. Jaccard's similarity co-efficient of SCoT markers ranged from 0.733 to 0.922 in female genotypes and 0.941 to 0.746 in male genotype population. Likewise, CBDP data analysis also revealed similarity ranging from 0.751 to 0.958 within female genotypes and 0.754 to 0.976 within male genotype populations thereby, indicating genetically diverse Jojoba population. Employing the NTSYS (Numerical taxonomy and multivariate analysis system) Version 2.1 software, both the markers generated dendrograms which revealed that all the Jojoba genotypes were clustered into two major groups, one group consisting of all female genotypes and another group comprising of all male genotypes. During the present investigation, CBDP markers proved more informative in studying genetic diversity among Jojoba. Such genetically diverse genotypes would thus be of great significance for breeding, management and conservation of elite (high yielding) Jojoba germplasm.

17.
Nanotechnology ; 25(37): 375601, 2014 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-25148433

RESUMEN

Fluorescent carbon dot (C-dot) nanoclusters composed of C-dot-loaded hollow silica spheres are obtained via the dehydration of mannose, which is adsorbed onto hollow silica spheres or poly(ethylene glycol)-graft-hollow silica spheres (PEG-g-hollow silica). The structure of C-dot nanoclusters are confirmed using 1H NMR, FTIR, TEM and TGA. C-dot nanoclusters show a redshifted fluorescence emission with an increased excitation wavelength. Passivation with PEG diamines improve the quantum yields to ∼2%. Confocal laser scanning microscopy (CLSM) results reflect the fact that C-dot nanoclusters can provide good cytoplasm imaging of live Hep G2 cells and live MCF-7 cells, and the imaging obtained is brighter and more even than those from free C-dots. With their combination of good photostability and low cytotoxicity, C-dot nanoclusters are promising for the production of higher quality bioimaging.


Asunto(s)
Carbono/química , Nanoestructuras/química , Imagen Óptica , Puntos Cuánticos/química , Citoplasma/química , Fluorescencia , Células Hep G2 , Humanos , Células MCF-7 , Microscopía Confocal , Nanoestructuras/ultraestructura , Dióxido de Silicio
18.
Macromol Biosci ; 14(3): 347-58, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24106152

RESUMEN

An optimized condition is identified to prepare linear poly(amido amine)s via Michael Addition polymerization of trifunctional amine, 4-(aminomethyl)piperidine (AMPD), with an equimolar diacrylamide, N,N-cystaminebis(acrylamide) (BAC). Poly(ethylene glycol) (PEG) and cholesterol (CE) are conjugated to linear poly(BAC-AMPD) through the reactions with the secondary amino groups in the backbone, respectively, to form poly(BAC-AMPD)-g-PEG-g-CE. The chemical structures of poly(BAC-AMPD) and poly(BAC-AMPD)-g-PEG-g-CE are characterized using NMR and gel permeation chromatography (GPC). Transmission electron microscopy (TEM), dynamic light scattering (DLS) and (1)H NMR results show that micelles with PEG shells and hydrophobic cores composed of poly(BAC-AMPD) and CE are formed via self-assembly of poly(BAC-AMPD)-g-PEG-g-CE in aqueous solution, and the micelles of poly(BAC-AMPD)-g-PEG-g-CE can be degraded by the presence of L-dithiothreitol and show a limited cytotoxicity in vitro. The anti-cancer drug, doxorubicin (DOX), can be loaded into the micelles. The DOX loaded micelles of poly(BAC-AMPD)-g-PEG-g-CE show pH- and redox-responsive drug release and redox-induced formation of aggregates, and it is shown that the DOX loaded micelles can deliver DOX into cells and show a higher efficacy in killing cancer cells than free drug.


Asunto(s)
Acrilamidas/química , Colesterol/química , Poliaminas/síntesis química , Polietilenglicoles/química , Antibióticos Antineoplásicos/química , Antibióticos Antineoplásicos/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Preparaciones de Acción Retardada , Doxorrubicina/química , Doxorrubicina/farmacología , Humanos , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Micelas , Oxidación-Reducción , Tamaño de la Partícula , Poliaminas/farmacología
19.
Macromol Rapid Commun ; 34(19): 1563-8, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23996916

RESUMEN

Rocket-like vesicles formed are composed of poly(acrylic aicd) (PMAA )/poly(ethylene glycol) (PEG) complex coated hollow silica spheres, and the structure and composition of the vesicles are characterized using TGA, (1)H NMR, FTIR, and TEM. Although only one-third of EG units of PEG brushes grafted to hollow silica spheres form the complex with PMAA via hydrogen bonding, the first "booster" layer composed of PMAA/PEG complex can provide secure encapsulation of model compound calcein blue under an acidic condition. The second "booster" layer composed of PEG brushes can be formed by changing acidic pH to 7.4 through the disassociation of the PMAA/PEG complex. A higher molecular weight PMAA exhibits a faster disassembly due to the formation of a looser PMAA/PEG complex on the surfaces of hollow silica spheres.


Asunto(s)
Portadores de Fármacos/química , Polietilenglicoles/química , Ácidos Polimetacrílicos/química , Dióxido de Silicio/química , Resinas Acrílicas/química , Concentración de Iones de Hidrógeno , Propiedades de Superficie
20.
Biomacromolecules ; 14(6): 2083-94, 2013 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-23692314

RESUMEN

Redox-responsive hyperbranched poly(amido amine)s (PAAs) with tertiary amino cores and amine, poly(ethylene glycol) (PEG) and hydroxyl terminal groups were prepared for DNA delivery respectively. The DNA condensation capability of PAAs was investigated using gel electrophoresis, and the results showed that PAA terminated with 1-(2-aminoethyl)piperazine (AEPZ) (BAA) is the most efficient in binding plasmid DNA (pDNA). The diameter and zeta-potential of polyplexes from PAAs were characterized using dynamic light scattering (DLS), and the morphology of the polyplexes was obtained using atomic force microscopy (AFM). All the PAAs were able to condense pDNA into nanoparticles with diameters between 50 and 200 nm with a positive surface charge when the weight ratio of polymer/DNA was higher than 20. Glutathione (GSH)-induced DNA release from polyplexes and the buffering capability of PAAs were investigated as well. Cytotoxicity of PAAs and in vitro gene transfection of polyplexes were evaluated in HEK293, COS-7, MCF-7 and Hep G2 cell lines, respectively. The results reflect that PAAs show remarkably low or even no cytotoxicity, and that PAA with amino terminal groups mediates the most efficient gene transfection with the transfection efficiency comparable to that of 25 kDa polyethylenimine. Further the effects of the presence of buthionine sulfoximine (BSO) on the transfection efficiency and cytotoxicity of BAA polyplexes were investigated.


Asunto(s)
Aminas/química , Técnicas de Transferencia de Gen , Poliaminas/administración & dosificación , Animales , Línea Celular , ADN/administración & dosificación , Humanos , Microscopía de Fuerza Atómica , Oxidación-Reducción , Plásmidos , Poliaminas/química
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