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1.
Sci Rep ; 10(1): 5566, 2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32221368

RESUMO

Avocado (Persea americana Mill.; Lauraceae) seed-derived polyhydroxylated fatty alcohols (PFAs) or polyols (i.e., avocadene and avocadyne) are metabolic modulators that selectively induce apoptosis of leukemia stem cells and reverse pathologies associated with diet-induced obesity. Delivery systems containing avocado polyols have not been described. Herein, natural surface active properties of these polyols are characterized and incorporated into self-emulsifying drug delivery systems (SEDDS) that rely on molecular self-assembly to form fine, transparent, oil-in-water (O/W) microemulsions as small as 20 nanometers in diameter. Mechanistically, a 1:1 molar ratio of avocadene and avocadyne (i.e., avocatin B or AVO was shown to be a eutectic mixture which can be employed as a novel, bioactive, co-surfactant that significantly reduces droplet size of medium-chain triglyceride O/W emulsions stabilized with polysorbate 80. In vitro cytotoxicity of avocado polyol-SEDDS in acute myeloid leukemia cell lines indicated significant increases in potency and bioactivity compared to conventional cell culture delivery systems. A pilot pharmacokinetic evaluation of AVO SEDDS in C57BL/6J mice revealed appreciable accumulation in whole blood and biodistribution in key target tissues. Lastly, incorporation of AVO in SEDDS significantly improved encapsulation of the poorly water-soluble drugs naproxen and curcumin.

2.
Soft Matter ; 15(45): 9205-9214, 2019 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-31710326

RESUMO

Peptides are a promising class of gelators, due to their structural simplicity, biocompatibility and versatility. Peptides were synthesized based on four amino acids: leucine, phenylalanine, tyrosine and tryptophan. These peptide gelators, with systematic structural variances in side chain structure and chain length, were investigated using Hansen solubility parameters to clarify molecular features that promote gelation in a wide array of solvents. It is of utmost importance to combine both changes to structural motifs and solvent in simultaneous studies to obtain a global perspective of molecular gelation. It was found that cyclization of symmetric dipeptides, into 2,5-diketopiperazines, drastically altered the gelation ability of the dipeptides. C-l-LL and C-l-YY, which are among the smallest peptide LMOGs reported to date, are robust gelators with a large radius of gelation (13.44 MPa1/2 and 13.90 MPa1/2, respectively), and even outperformed l-FF (5.61 MPa1/2). Interestingly, both linear dipeptides (l-FF and l-LL) gelled similar solvents, yet when cyclized only cyclo-dityrosine was a robust gelator, while cyclo-diphenylalanine was not. Changes in the side chains drastically affected the crystal morphology of the resultant gels. Symmetric cyclo dipeptides of leucine and tyrosine were capable of forming extremely high aspect ratio fibers in numerous solvents, which represent new molecular motifs capable of driving self-assembly.


Assuntos
Peptídeos/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Ciclização , Géis , Solubilidade
3.
Food Funct ; 10(12): 8195-8207, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31701112

RESUMO

Altering sn-fatty acid position of glycerol mono-oleate (GMO) from sn-1 to sn-2 decreases fatty acid bioaccessibility by 25.9% providing possible strategies to tailor lipemic responses of food emulsions. Lipid digestion kinetics and fatty acid bioaccessibility of monomodal O/W emulsions stabilized at their minimum surfactant concentration (0.5 < MSC > 0.7 (w/w)) were studied in the TNO Intestinal Model (TIM-1) gastrointestinal (GI) tract. No significant differences were observed between induction times nor rate constants when using 1-GMO and 1-GMS, Span 60, Tween 60 and Tween 80 as surfactants in O/W emulsions, as determined by fitting a three-parameter shifted logistic model to the cumulative bioaccessibility. Comparable trends were observed between area under the curve (AUC) of the absolute bioaccessibility and total overall bioaccessibility.


Assuntos
Lipídeos/química , Tensoativos/química , Água/química , Digestão , Emulsões/química , Emulsões/metabolismo , Trato Gastrointestinal/química , Trato Gastrointestinal/metabolismo , Cinética , Metabolismo dos Lipídeos , Modelos Biológicos , Peso Molecular , Polissorbatos/química , Polissorbatos/metabolismo , Tensoativos/metabolismo , Água/metabolismo
4.
Pharmaceutics ; 11(4)2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30987004

RESUMO

Phyto-phospholipid complexes have been developed as a common way of improving the oral bioavailability of poorly absorbable phyto-pharmaceuticals; however, the complexation with phospholipids can induce positive or negative effects on the bioaccessibility of such plant-derived active ingredients in different parts of the gastrointestinal tract (GIT). The purpose of this study was to investigate the effects of phospholipid complexation on the bioaccessibility of a rosmarinic acid-phospholipid complex (RA-PLC) using the TNO dynamic intestinal model-1 (TIM-1). Preparation of RA-PLC was confirmed using X-ray diffraction, Fourier-transform infrared spectroscopy, partition coefficient measurement, and Caco-2 monolayer permeation test. Bioaccessibility parameters in different GIT compartments were investigated. Complexation by phospholipids reduced the bioaccessibility of RA in jejunum compartment, while maintaining the ileum bioaccessibility. The overall bioaccessibility of RA-PLC was lower than the unformulated drug, suggesting that the improved oral absorption from a previous animal study could be considered as a net result of decreased bioaccessibility overwhelmed by enhanced intestinal permeability. This study provides insights into the effects of phospholipid on the bioaccessibility of hydrophilic compounds, and analyzes them based on the relationship between bioaccessibility, membrane permeability, and bioavailability. Additionally, TIM-1 shows promise in the evaluation of dosage forms containing materials with complicated effects on bioaccessibility.

5.
J Sci Food Agric ; 98(12): 4488-4494, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29460434

RESUMO

BACKGROUND: The objectives of this study were to: (a) select an ideal organogel for the oil phase of a novel gel encapsulation technology, (b) optimize the formulation of an organogel and sodium alginate-based gel complex, and (c) examine the rumen protective ability of the gel by measuring 48-h in vitro ruminal dry matter disappearance and gas production from encapsulated dried and ground holy basil leaves. RESULTS: A rice-bran wax and canola oil organogel was selected for the oil phase of the gel complex as this combination had a 48-h dry matter disappearance of 6%, the lowest of all organogels analyzed. The gel complex was formulated by homogenizing the organogel with a sodium alginate solution to create a low-viscosity oil-in-water emulsion. Average dry matter disappearance of gel-encapsulated holy basil was 19%, compared to 42% for the free, unprotected holy basil. However, gel encapsulation of holy basil stimulated gas production. Specifically, gas production of encapsulated holy basil was four times higher than the treatment with holy basil added on top of the gel prior to incubation rather than encapsulated within the gel. CONCLUSION: Although the gel itself was highly degradable, it is speculated encapsulation thwarted holy basil's antimicrobial activity. © 2018 Society of Chemical Industry.


Assuntos
Alginatos/química , Gases/metabolismo , Ocimum sanctum/metabolismo , Oryza/química , Extratos Vegetais/química , Óleo de Brassica napus/química , Rúmen/metabolismo , Ração Animal/análise , Animais , Géis/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Ocimum sanctum/química , Ceras/química
6.
Crit Rev Food Sci Nutr ; 58(11): 1902-1916, 2018 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-28662357

RESUMO

Fluorescent molecular rotors (MRs) are compounds whose emission is modulated by segmental mobility; photoexcitation generates a locally excited (LE), planar state that can relax either by radiative decay (emission of a photon) or by formation of a twisted intramolecular charge transfer (TICT) state that can relax nonradiatively due to internal rotation. If the local environment around the probe allows for rapid internal rotation in the excited state, fast non-radiative decay can either effectively quench the fluorescence or generate a second, red-shifted emission band. Conversely, any environmental restriction to twisting in the excited state due to free volume, crowding or viscosity, slows rotational relaxation and promotes fluorescence emission from the LE state. The environmental sensitivity of MRs has been exploited extensively in biological applications to sense microviscosity in biofluids, the stability and physical state of biomembranes, and conformational changes in macromolecules. The application of MRs in food research, however, has been only marginally explored. In this review, we summarize the main characteristics of fluorescent MRs, their current applications in biological research and their current and potential applications as sensors of physical properties in food science and engineering.


Assuntos
Corantes Fluorescentes/química , Tecnologia de Alimentos , Fluorescência , Interações Hidrofóbicas e Hidrofílicas , Sondas Moleculares/química , Estrutura Molecular , Conformação Proteica , Dobramento de Proteína , Proteínas/química , Proteólise , Relação Estrutura-Atividade , Viscosidade
7.
Langmuir ; 33(41): 10907-10916, 2017 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-28926708

RESUMO

1,3:2,4-Dibenzylidene-d-sorbitol (DBS) is the gold-standard for low-molecular-weight organogelators (LMOGs). DBS gels a wide array of solvents, as illustrated by the large Hansen sphere representing gels (2δd = 33.5 MPa1/2, δp = 7.5 MPa1/2, and δh = 8.7 MPa1/2; radius = 11.2 MPa1/2). Derivatives of DBS have been synthesized to isolate and determine molecular features essential for organogelation. In this work, π-π stacking and hydrogen bonding are the major noncovalent interactions examined. The importance of π-π stacking was studied using 1,3:2,4 dicyclohexanecarboxylidene-d-sorbitol (DCHS), which eliminates possible π-π stacking while still conserving the other structural aspects of DBS. The replacement of the benzyl groups with cyclohexyl groups led to a very a poor gelator; only one of the several solvents examined, carbon tetrachloride, formed a gel. 1,3:2,4-Diethylidene-d-sorbitol (DES), another DBS analogue incapable of π-π stacking but with very different polarity, gelated a large Hansen space (2δd = 34.0 MPa1/2, δp = 10.9 MPa1/2, and δh = 10.8 MPa1/2; radius = 9.2 MPa1/2). DES gels solvents with higher δp and δh values than DBS. To assess the role of hydrogen bonding, DBS was acetalated (A-DBS), and it was found that the Hansen space gelated by A-DBS shifted to less polar solvents with higher hydrogen-bonding Hansen solubility parameters (HSPs) (2δd = 33.8 MPa1/2, δp = 6.3 MPa1/2, and δh = 9.6 MPa1/2; radius = 11.1 MPa1/2) than for DBS. These systematic structural modifications are the first step in exploring how specific intermolecular features alter aspects of Hansen space corresponding to positive gelation outcomes.

8.
Food Sci Nutr ; 5(3): 579-587, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28572944

RESUMO

Short-chain ceramides, such as N-acetoyl-d-erythro-sphingosine (C2), have a remarkable ability to structure edible oils, such as canola oil, into self-standing organogels without any added saturated or trans fats. These short-chain ceramides are ubiquitously found in foods ranging from eggs to soybeans. As the ceramide fatty acid chain length increases, there is an increase in the melting temperature of the organogel and a decrease in the elastic modulus. Gelation ability is lost at 2 wt% when the fatty acid chain length increases to six carbons; however, organogels form at 5 wt% up to 18 carbons. Short-chain ceramides, C2, decrease cell viability of colon, prostate, ovarian, and leukemia cell lines, while ceramides with long-chain fatty acids, C18, do not affect the viability of these cancer cell lines. This suggests that a bioactive spreadable fat, with no trans or added saturated fat, with the potential to alter the viability of cancer cell growth, is possible.

9.
Langmuir ; 32(48): 12833-12841, 2016 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-27809551

RESUMO

Changes in solvent chemistry influenced kinetics of both nucleation and crystallization of 12-hydroxyoctadecenoic, as determined using differential scanning calorimetry and applying a modified Avrami model to the calorimetric data. Altering solvent properties influenced solvent-gelator compatibility, which in turn altered the chemical potential of the system at the onset of crystallization, the kinetics of gelation, and the resulting 12HOA crystal fiber length. The chemical potential at the onset of crystallization was linearly correlated to both the hydrogen-bonding Hansen solubility parameter and the solvent-gelator vectorial distance in Hansen space, Ra. Our work suggests that solvent properties can be modulated to affect the solubility of 12HOA, which in turn influences the kinetics of crystallization and the self-assembly of this organogelator into supramolecular crystalline structures. Therefore, modulation of solvent properties during organogelation can be used to control fiber length and thus engineer the physical properties of the gel.

10.
Tumour Biol ; 37(9): 12485-12495, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27337954

RESUMO

Increased expression of insulin-like growth factor 2 (IGF2) is found in tumors of colorectal cancer (CRC) patients exhibiting a gained region on chromosome 11q15 and is implicated in poor patient survival. This study analyzes in vitro phenotypic- and gene expression changes associated with IGF2 shRNA-mediated knockdown. Initially, doxycycline inducible IGF2 knockdown cell lines were generated in the CRC cell lines SW480 and LS174T. The cells were analyzed for changes in proliferation, cell cycle, apoptosis, adhesion, and invasion. Expression profiling analysis was performed, and, for a subset of the identified genes, expression was validated by qRT-PCR and Western blot. IGF2 knockdown inhibited cell proliferation in both cell lines induced G1 cell cycle blockade and decreased adhesion to several extracellular matrix proteins. Knockdown of IGF2 did not alter invasiveness in SW480 cells, while a slight increase in apoptosis was seen only in the LS174T cell line. Knockdown of IGF2 in SW480 deregulated 58 genes, several of which were associated with proliferation and cell-cell/cell-ECM contacts. A subset of these genes, including CDK2, YAP1, and BIRC5 (Survivin), are members of a common network. This study supports the concept of direct autocrine/paracrine tumor cell activation through IGF2 and a shows role of IGF2 in CRC proliferation, adhesion and, to a limited extent, apoptosis.


Assuntos
Neoplasias Colorretais/patologia , Fator de Crescimento Insulin-Like II/fisiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Antígenos CD , Caderinas/genética , Adesão Celular , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/genética , Neoplasias Colorretais/mortalidade , Quinase 2 Dependente de Ciclina/fisiologia , Desmoplaquinas/genética , Humanos , Fator de Crescimento Insulin-Like II/genética , Fosfoproteínas/genética , RNA Interferente Pequeno/genética , Fatores de Transcrição , gama Catenina
11.
J Cancer Res Clin Oncol ; 142(1): 225-37, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26243458

RESUMO

PURPOSE: CITED4 is one member of a family of transcriptional cofactors, several of which are deregulated in a variety of tumors, including colorectal cancer (CRC). We modulated CITED4 expression, in vitro, and analyzed the associated phenotypic and gene expression changes. METHODS: CITED4-overexpressing and shRNA-mediated knockdown cell lines and control cell lines were established in the CRC cell line SW480. The cells were analyzed for changes in proliferation, apoptosis/cell cycle, migration, invasion, colony formation and adhesion. mRNA expression changes were determined by microarray and pathway analysis, and several deregulated genes were validated by qRT-PCR and Western blotting. Based on results obtained from these studies, the status of the actin cytoskeleton was evaluated by phalloidin/vinculin staining. RESULTS: Phenotypically, the CITED4-overexpressing cell line showed only moderate changes in adhesion. Microarray analysis identified several deregulated genes, including several G protein-coupled receptors. Phenotypic analysis of the CITED4 shRNA knockdown cell line demonstrated decreased cell proliferation and G2 cell cycle blockage. Microarray analysis identified many deregulated genes, and pathway analysis discovered genes linked to actin-associated adherens junctions/tight junctions (claudin-4, claudin-7, ezrin, MET, ß-catenin). Phenotypically, no morphological changes of the actin cytoskeleton were seen. CONCLUSIONS: Upregulation of CITED4 in SW480 resulted in no obvious phenotype. CITED4 shRNA-mediated knockdown led to decreased cellular proliferation and modulation of a large number of genes, including the c-MET tyrosine kinase and several actin-associated adherens junctions/tight junction genes.


Assuntos
Junções Aderentes/genética , Biomarcadores Tumorais/genética , Proliferação de Células , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Inativação Gênica , Junções Íntimas/genética , Fatores de Transcrição/metabolismo , Actinas/metabolismo , Apoptose , Biomarcadores Tumorais/metabolismo , Western Blotting , Neoplasias Colorretais/genética , Perfilação da Expressão Gênica , Humanos , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Células Tumorais Cultivadas
12.
Cell Tissue Res ; 363(3): 735-50, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26340985

RESUMO

Among the 26 human type II keratins, K78 is the only one that has not yet been explored with regard to its expression characteristics. Here, we show that, at both the transcriptional and translational levels, K78 is strongly expressed in the basal and parabasal cell layers with decreasing intensity in the lower suprabasal cells of keratinising and non-keratinising squamous epithelia and keratinocyte cultures. The same pattern has been detected at the transcriptional level in the corresponding mouse epithelia. Murine K78 protein, which contains an extraordinary large extension of its tail domain, which is unique among all known keratins, is not detectable by the antibody used. Concomitant studies in human epithelia have confirmed K78 co-expression with the classical basal keratins K5 and K14. Similarly, K78 co-expression with the differentiation-related type I keratins K10 (epidermis) and K13 (non-keratinising epithelia) occurs in the parabasal cell layer, whereas that of the corresponding type II keratins K1 (epidermis) and K4 (non-keratinising epithelia) unequivocally starts subsequent to the respective type I keratins. Our data concerning K78 expression modify the classical concept of keratin pair K5/K14 representing the basal compartment and keratin pairs K1/K10 or K4/K13 defining the differentiating compartment of stratified epithelia. Moreover, the K78 expression pattern and the decoupled K1/K10 and K4/K13 expression define the existence of a hitherto unperceived early differentiation stage in the parabasal layer characterized by K78/K10 or K78/K13 expression.


Assuntos
Epitélio/metabolismo , Regulação da Expressão Gênica , Queratinas Tipo II/genética , Queratinas Tipo II/metabolismo , Adulto , Sequência de Aminoácidos , Animais , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Desenvolvimento Embrionário , Epiderme/metabolismo , Evolução Molecular , Imunofluorescência , Loci Gênicos , Humanos , Hibridização In Situ , Queratinócitos/metabolismo , Queratinas Tipo II/química , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Transporte Proteico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Análise de Sequência de Proteína
13.
Oncoscience ; 2(10): 801-2, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26682252
14.
Mol Pharm ; 12(7): 2229-36, 2015 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-25984595

RESUMO

The oral bioavailability of hydrophobic compound is usually limited by the poor aqueous solubility in the gastrointestinal (GI) tract. Various oral formulations were developed to enhance the systemic concentration of such molecules. Moreover, compounds with high melting temperature that appear as insoluble crystals imposed a great challenge to the development of oral vehicle. Polymethoxyflavone, an emerging category of bioactive compounds with potent therapeutic efficacies, were characterized as having a hydrophobic and highly crystalline chemical structure. To enhance the oral dosing efficiency of polymethoxyflavone, a viscoelastic emulsion system with a high static viscosity was developed and optimized using tangeretin, one of the most abundant polymethoxyflavones found in natural sources, as a modeling compound. In the present study, different in vitro and in vivo models were used to mechanistically evaluate the effect of emulsification on oral bioavailability of tangeretin. In vitro lipolysis revealed that emulsified tangeretin was digested and became bioaccessible much faster than unprocessed tangeretin oil suspension. By simulating the entire human GI tract, TNO's gastrointestinal model (TIM-1) is a valuable tool to mechanistically study the effect of emulsification on the digestion events that lead to a better oral bioavailability of tangeretin. TIM-1 result indicated that tangeretin was absorbed in the upper GI tract. Thus, a higher oral bioavailability can be expected if the compound becomes bioaccessible in the intestinal lumen soon after dosing. In vivo pharmacokinetics analysis on mice again confirmed that the oral bioavailability of tangeretin increased 2.3 fold when incorporated in the viscoelastic emulsion than unformulated oil suspension. By using the combination of in vitro and in vivo models introduced in this work, the mechanism that underlie the effect of viscoelastic emulsion on the oral bioavailability of tangeretin was well-elucidated.


Assuntos
Emulsões/química , Flavonas/química , Flavonas/farmacocinética , Substâncias Viscoelásticas/química , Administração Oral , Animais , Disponibilidade Biológica , Química Farmacêutica/métodos , Cristalização/métodos , Digestão/fisiologia , Portadores de Fármacos/química , Feminino , Trato Gastrointestinal/metabolismo , Humanos , Absorção Intestinal/fisiologia , Lipólise/efeitos dos fármacos , Camundongos , Solubilidade/efeitos dos fármacos
15.
Biomacromolecules ; 15(9): 3406-11, 2014 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-25082798

RESUMO

The bioaccessibility of salicylic acid (SA) can be effectively modified by incorporating the pharmacological compound directly into polymers such as poly(anhydride-esters). After simulated digestion conditions, the bioaccessibility of SA was observed to be statistically different (p < 0.0001) in each sample: 55.5 ± 2.0% for free SA, 31.2 ± 2.4% the SA-diglycolic acid polymer precursor (SADG), and 21.2 ± 3.1% for SADG-P (polymer). The release rates followed a zero-order release rate that was dependent on several factors, including (1) solubilization rate, (2) macroscopic erosion of the powdered polymer, (3) hydrolytic cleavage of the anhydride bonds, and (4) subsequent hydrolysis of the polymer precursor (SADG) to SA and diglycolic acid.


Assuntos
Amiloide , Ouro/química , Nanopartículas Metálicas/química , Peptídeos , Poliésteres , Ácido Salicílico , Amiloide/síntese química , Amiloide/química , Disponibilidade Biológica , Peptídeos/síntese química , Peptídeos/química , Poliésteres/síntese química , Poliésteres/química , Poliésteres/farmacologia , Ácido Salicílico/química , Ácido Salicílico/farmacocinética
16.
Langmuir ; 30(47): 14128-42, 2014 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-24849281

RESUMO

Solvent properties play a central role in mediating the aggregation and self-assembly of molecular gelators and their growth into fibers. Numerous attempts have been made to correlate the solubility parameters of solvents and gelation abilities of molecular gelators, but a comprehensive comparison of the most important parameters has yet to appear. Here, the degree to which partition coefficients (log P), Henry's law constants (HLC), dipole moments, static relative permittivities (ε(r)), solvatochromic E(T)(30) parameters, Kamlet-Taft parameters (ß, α, and π), Catalan's solvatochromic parameters (SPP, SB, and SA), Hildebrand solubility parameters (δ(i)), and Hansen solubility parameters (δ(p), δ(d), δ(h)) and the associated Hansen distance (R(ij)) of 62 solvents (covering a wide range of properties) can be correlated with the self-assembly and gelation of 1,3:2,4-dibenzylidene sorbitol (DBS) gelation, a classic molecular gelator, is assessed systematically. The approach presented describes the basis for each of the parameters and how it can be applied. As such, it is an instructional blueprint for how to assess the appropriate type of solvent parameter for use with other molecular gelators as well as with molecules forming other types of self-assembled materials. The results also reveal several important insights into the factors favoring the gelation of solvents by DBS. The ability of a solvent to accept or donate a hydrogen bond is much more important than solvent polarity in determining whether mixtures with DBS become solutions, clear gels, or opaque gels. Thermodynamically derived parameters could not be correlated to the physical properties of the molecular gels unless they were dissected into their individual HSPs. The DBS solvent phases tend to cluster in regions of Hansen space and are highly influenced by the hydrogen-bonding HSP, δ(h). It is also found that the fate of this molecular gelator, unlike that of polymers, is influenced not only by the magnitude of the distance between the HSPs for DBS and the HSPs of the solvent, R(ij), but also by the directionality of R(ij): if the solvent has a larger hydrogen-bonding HSP (indicating stronger H-bonding) than that of the DBS, then clear gels are formed; opaque gels form when the solvent has a lower δ(h) than does DBS.


Assuntos
Sorbitol/análogos & derivados , Géis/química , Ligação de Hidrogênio , Solubilidade , Solventes/química , Sorbitol/química
17.
Langmuir ; 29(21): 6467-75, 2013 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-23672543

RESUMO

A systematic study of the importance of functional group position and type on the gelator efficiencies of structurally simple, low molecular-mass gelators is reported. Thus, the gelation abilities of a series of positional isomers of ketooctadecanoic acid (n-KSA) are compared in a wide range of liquids. The gelation abilities of the n-KSA as a function of n, the keto group position along the chain, are characterized by several structural, thermal, and rheological techniques and are compared with those of the corresponding hydroxyoctadecanoic acid isomers (n-HSA) and the parent molecule, octadecanoic acid (SA). Analyses of the gels according to the strengths of functional group interactions along the alkyl chain in terms of group position and type are made. The conclusions derived from the study indicate that gel stability is enhanced when the functional group is located relatively far from the carboxylic headgroup and when group-group interactions are stronger (i.e., hydrogen-bonding interactions are stronger in the n-HSA than dipole interactions in the n-KSA, which are stronger than the London dispersion interactions in SA). Co-crystals of the keto- and hydroxy-substituted octadecanoic acids are found to be less efficient gelators than even the ketooctadecanoic acids, due to molecular packing and limited group interactions within the gelator networks.


Assuntos
Ácidos Esteáricos/química , Géis/síntese química , Géis/química , Ligação de Hidrogênio , Estrutura Molecular , Ácidos Esteáricos/síntese química , Temperatura de Transição
18.
Langmuir ; 29(18): 5617-21, 2013 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-23590644

RESUMO

12-Hydroxystearic acid (12-HSA) xerogels derived from 12-HSA-acetronitrile organogels are highly effective sorbent materials capable of adsorbing apolar, spilled materials in aqueous environments. 12-HSA xerogels made from 12-HSA-acetronitrile organogels are more effective than 12-HSA xerogels made from 12-HSA-pentane organogels because of the highly branched fibrillar networks established in acetonitrile molecular gels. This difference arises because of dissimilarities in the network structure between 12-HSA in various solvents. These xerogels, being thermoreversible, allow for both the spilled oil to be reclaimed but also the gelator may be reused to engineer new xerogels for oil spill containment and cleanup.


Assuntos
Hidrogéis/química , Óleos/química , Ácidos Esteáricos/química , Adsorção , Tamanho da Partícula , Propriedades de Superfície
19.
Infect Dis Obstet Gynecol ; 2013: 909354, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24382940

RESUMO

The human vagina is colonized by a variety of indigenous microflora; in healthy individuals the predominant bacterial genus is Lactobacillus while those with bacterial vaginosis (BV) carry a variety of anaerobic representatives of the phylum Actinobacteria. In this study, we evaluated the antimicrobial activity of benzoyl peroxide (BPO) encapsulated in a hydrogel against Gardnerella vaginalis, one of the causative agents of BV, as well as indicating its safety for healthy human lactobacilli. Herein, it is shown that in well diffusion assays G. vaginalis is inhibited at 0.01% hydrogel-encapsulated BPO and that the tested Lactobacillus spp. can tolerate concentrations of BPO up to 2.5%. In direct contact assays (cells grown in a liquid culture containing hydrogel with 1% BPO or BPO particles), we demonstrated that hydrogels loaded with 1% BPO caused 6-log reduction of G. vaginalis. Conversely, three of the tested Lactobacillus spp. were not inhibited while L. acidophilus growth was slightly delayed. The rheological properties of the hydrogel formulation were probed using oscillation frequency sweep, oscillation shear stress sweep, and shear rate sweep. This shows the gel to be suitable for vaginal application and that the encapsulation of BPO did not alter rheological properties.


Assuntos
Resinas Acrílicas , Antibacterianos/farmacologia , Peróxido de Benzoíla/farmacologia , Gardnerella vaginalis/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/prevenção & controle , Hidrogel de Polietilenoglicol-Dimetacrilato/farmacologia , Vaginose Bacteriana/prevenção & controle , Resinas Acrílicas/farmacologia , Portadores de Fármacos , Feminino , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Lactobacillus/efeitos dos fármacos , Testes de Sensibilidade Microbiana
20.
Genes Chromosomes Cancer ; 52(3): 250-64, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23074073

RESUMO

Invasion is a critical step in lung tumor progression. The interaction between tumor cells and their surroundings may play an important role in tumor invasion and metastasis. To better understand the mechanisms of tumor invasion and tumor-microenvironment interactions in lung tumors, total RNA was isolated from the inner tumor, tumor invasion front, adjacent lung, and distant normal lung tissue from 17 patients with primary squamous cell lung carcinoma using punch-aided laser capture microdissection. Messenger RNA expression profiles were obtained by microarray analysis, and microRNA profiles were generated from eight of these samples using TaqMan Low Density Arrays. Statistical analysis of the expression data showed extensive changes in gene expression in the inner tumor and tumor front compared with the normal lung and adjacent lung tissue. Only a few genes were differentially expressed between tumor front and the inner tumor. Several genes were validated by immunohistochemistry. Evaluation of the microRNA data revealed zonal expression differences in nearly a fourth of the microRNAs analyzed. Validation of selected microRNAs by in situ hybridization demonstrated strong expression of hsa-miR-196a in the inner tumor; moderate expression of hsa-miR-224 in the inner tumor and tumor front, and strong expression of hsa-miR-650 in the adjacent lung tissue. Pathway analysis placed the majority of genes differentially expressed between tumor and nontumor cells in intrinsic processes associated with inflammation and extrinsic processes related to lymphocyte physiology. Genes differentially expressed between the inner tumor and the adjacent lung/normal lung tissue affected pathways of arachidonic acid metabolism and eicosanoid signaling.


Assuntos
Carcinoma de Células Escamosas/genética , Perfilação da Expressão Gênica , Neoplasias Pulmonares/genética , Transcriptoma , Microambiente Tumoral/genética , Carcinoma de Células Escamosas/patologia , Análise por Conglomerados , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/patologia , MicroRNAs/genética , Reprodutibilidade dos Testes
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