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1.
Molecules ; 29(18)2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39339281

RESUMO

In this paper, a series of tetrameric surfactants (4CnSAZs, n = 12, 14, 16) endowed with zwitterionic characteristic were synthesized by a simple and convenient method and their structures were characterized by FT-IR, 1H NMR and elemental analysis. Their physicochemical properties were studied using the Wilhelmy plate method, fluorescence spectra and dynamic light scattering technique. 4CnSAZs have higher surface activities and tend to adsorb at the air/water surface rather than self-assembling in aqueous solution. The thermodynamic parameters obtained from surface tension measurements show that both processes of adsorption and micellization of 4CnSAZs are spontaneous and that the micellization processes of 4CnSAZs are entropy-driven processes. Both adsorption and micellization of 4CnSAZs are inclined to occur with the increase of alkyl chain length or temperature. For 4C12SAZs, there are only small-size aggregates (micelles), while the large aggregates (vesicles) are observed at the alkyl length of 4CnSAZs of 14 or 16. This shows that the alkyl chain length for oligomeric surfactants has a greater sensitivity for aggregate growth. The aggregate morphologies obtained from the calculated values of critical packing parameter (p) for 4C14SAZs and 4C16SAZs can be supported by the DLS measurement results. The test results obtained by the separation-water-time method show that 4CnSAZs have good emulsification performance and that the prepared emulsions appear to exit in the form of multiple emulsions. In addition, 4CnSAZs have good antibacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The present study reveals the unique behavior of a zwitterionic tetrameric surfactant and may give new insights into molecular design and synthesis of a high degree of surfactants with different structure characteristics for potential application in various industrial fields.


Assuntos
Antibacterianos , Tensoativos , Tensoativos/química , Tensoativos/farmacologia , Tensoativos/síntese química , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Tensão Superficial , Termodinâmica , Emulsões/química , Testes de Sensibilidade Microbiana , Micelas , Staphylococcus aureus/efeitos dos fármacos , Adsorção , Propriedades de Superfície , Escherichia coli/efeitos dos fármacos
2.
Int J Mol Sci ; 21(3)2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32019109

RESUMO

An increasing number of multidrug-resistant pathogens is a serious problem of modern medicine and new antibiotics are highly demanded. In this study, different n-alkyl acids (C2-C14) and aromatic acids (benzoic and trans-cinnamic) were conjugated to the N-terminus of KR12 amide. The effect of this modification on antimicrobial activity (ESKAPE bacteria and biofilm of Staphylococcus aureus) and cytotoxicity (human red blood cells and HaCaT cell line) was examined. The effect of lipophilic modifications on helicity was studied by CD spectroscopy, whereas peptide self-assembly was studied by surface tension measurements and NMR spectroscopy. As shown, conjugation of the KR12-NH2 peptide with C4-C14 fatty acid chains enhanced the antimicrobial activity with an optimum demonstrated by C8-KR12-NH2 (MIC 1-4 µg/mL against ESKAPE strains; MBEC of S. aureus 4-16 µg/mL). Correlation between antimicrobial activity and self-assembly behavior of C14-KR12-NH2 and C8-KR12-NH2 has shown that the former self-assembled into larger aggregated structures, which reduced its antimicrobial activity. In conclusion, N-terminal modification can enhance antimicrobial activity of KR12-NH2; however, at the same time, the cytotoxicity increases. It seems that the selectivity against pathogens over human cells can be achieved through conjugation of peptide N-terminus with appropriate n-alkyl fatty and aromatic acids.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Ácidos Graxos/química , Fragmentos de Peptídeos/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Eritrócitos/efeitos dos fármacos , Humanos , Imidazóis/química , Lipopeptídeos , Nylons/química , Fragmentos de Peptídeos/química , Infecções Estafilocócicas/microbiologia , Propriedades de Superfície , Catelicidinas
3.
Chemphyschem ; 20(21): 2774-2782, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31544288

RESUMO

Diphenylalanine (FF) represents one of the most studied self-assembling peptides. As a consequence of non-covalent interactions (aromatic stacking and hydrogen bonds), FF is able to generate different nanoarchitectures, proposed in the last years as innovative tools for several applications. The identification of the relationship between the chemical building block composition and the supramolecular structure of final material is the objective of intense research. Different FF analogues were synthetized and studied. At the state of art, in the high number of FF derivatives, PEGylation has not been studied yet, notwithstanding its role has been demonstrated for longer poly-phenylalanine peptides. Herein, we describe the synthesis and the supramolecular behavior of two PEGylated-FF derivatives, PEG2-FF and PEG6-FF, in which the zwitterionic FF has been derivatized at the N-terminus with two or six ethoxylic moieties, respectively. Spectroscopic methodologies (fluorescence, circular dichroism, Fourier transform infrared) allowed the identification of their secondary structure and the calculation of the critical aggregation concentration. PEGylation of the dipeptide induces a modification of the conformational organization from nanotubes with hexagonal symmetry to ß-sheet rich fibrils. This structural organization confers photoluminescence features to the supramolecular structures.

4.
Mol Pharm ; 15(3): 962-974, 2018 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-29345955

RESUMO

Methods were developed to systematically screen different polymer-surfactant combinations for the purpose of enhancing amorphous active pharmaceutical ingredient (API) solubility while maintaining its physical stability. Itraconazole (ITZ) was chosen as the model API mostly due to its low aqueous solubility. Special attention was paid to determine the effect of a reduction in the critical micelle concentration (CMC) by specific polymer/surfactant combinations on the ITZ solubility and physical stability. However, only a slight correlation was actually found. Only the polymer/surfactant combinations with the smallest effect on CMC improved solubility and stability of ITZ in simulated intestinal fluids (SIF). Surfactants were found to negate the stabilizing effects of polymers. ITZ crystallization tendency generally depended on the degree of supersaturation and the type of polymer/surfactant combinations used. In general, we found that instead of focusing solely on reducing the CMC, a systematic screening of systems that maintain high ITZ supersaturation proved to be a successful approach.


Assuntos
Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Excipientes/química , Itraconazol/farmacocinética , Varredura Diferencial de Calorimetria , Cristalização , Itraconazol/química , Micelas , Polímeros/química , Tensoativos/química
5.
Biopolymers ; 105(4): 199-211, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26574155

RESUMO

In this work, isothermal titration and differential scanning calorimetric methods, in combination with pyrene fluorescence emission and dynamic light scattering have been used to investigate the interaction of dodecyltrimethylammonium bromide (DTAB) with the giant extracellular Glossoscolex paulistus hemoglobin (HbGp) in the oxy-form, at pH values around the isoelectric point (pI ≈ 5.5). Our ITC results have shown that the interaction of DTAB with the hemoglobin is more intense at pH 7.0, with a smaller cac (critical aggregation concentration) value. The increase of protein concentration does not influence the cac value of the interaction, at both pH values. Therefore, the beginning of the DTAB-oxy-HbGp premicellar aggregates formation, in the cac region, is not affected by the increase of protein concentration. HSDSC studies show higher Tm values at pH 5.0, in the absence and presence of DTAB, when compared with pH 7.0. Furthermore, at pH 7.0, an aggregation process is observed with DTAB in the range from 0.75 to 1.5 mmol/L, noticed by the exothermic peak, and similar to that observed for pure oxy-HbGp, at pH 5.0, and in the presence of DTAB. DLS melting curves show a decrease on the hemoglobin thermal stability for the oxy-HbGp-DTAB mixtures and formation of larger aggregates, at pH 7.0. Our present data, together with previous results, support the observation that the protein structural changes, at pH 7.0, occur at smaller DTAB concentrations, as compared with pH 5.0, due to the acidic pI of protein that favors the oxy-HbGp-cationic surfactant interaction at neutral pH.


Assuntos
Brometos/química , Ponto Isoelétrico , Oxiemoglobinas/química , Compostos de Amônio Quaternário/química , Animais , Varredura Diferencial de Calorimetria , Cátions , Oligoquetos
6.
J Food Sci Technol ; 53(12): 4187-4196, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28115759

RESUMO

Starch was dually chemically modified for developing food-grade ingredients of lower digestibility and their properties were compared to those of single modified and native starches. Hydroxypropylation with propylene oxide (HP) followed by esterification with octenylsuccinic anhydride (OSA) of potato starch (P-native) produced derivatives with lower digestibility than esterification solely with OSA. The dextrose equivalent, maltose and glucose contents, which were used as the main indicators for in vitro digestion, were lower for modified starches. P-HP0.2-OSA0.0200 derivative was the least digestible; the glucose and maltose contents were lowered by 28.3 and 42.1% compared to P-native. The aggregation behavior of enzymatically hydrolyzed starch derivatives was studied in aqueous solution by employing the fluorescence probe and dynamic light scattering techniques. The critical aggregation concentration for OSA modified and dually modified starches varied from 1.2 to 3 g/L and from 0.125 to 0.48 g/L, respectively, depending on the degree of OSA substitution. The study showed that above a critical concentration the hydrolyzates of modified starches tend to form the aggregates with different properties depending both on the degree of OSA substitution and chemical structure.

7.
Bioorg Med Chem ; 23(13): 3566-73, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-25936261

RESUMO

Two novel series of tris-cationic, tripled-headed, double-tailed amphiphiles were synthesized and the effects of tail length and head group composition on the critical aggregation concentration (CAC), thermodynamic parameters, and minimum inhibitory concentration (MIC) against six bacterial strains were investigated. Synergistic antibacterial combinations of these amphiphiles were also identified. Amphiphiles in this study are composed of a benzene core with three benzylic ammonium bromide groups, two of which have alkyl chains, each 8-16 carbons in length. The third head group is a trimethylammonium or pyridinium. Log of critical aggregation concentration (log[CAC]) and heat of aggregation (ΔHagg) were both inversely proportional to the length of the linear hydrocarbon chains. Antibacterial activity increases with tail length until an optimal tail length of 12 carbons per chain, above which, activity decreased. The derivatives with two 12 carbon chains had the best antibacterial activity, killing all tested strains at concentrations of 1-2µM for Gram-positive and 4-16µM for Gram-negative bacteria. The identity of the third head group (trimethylammonium or pyridinium) had minimal effect on colloidal and antibacterial activity. The antibacterial activity of several binary combinations of amphiphiles from this study was higher than activity of individual amphiphiles, indicating that these combinations are synergistic. These amphiphiles show promise as novel antibacterial agents that could be used in a variety of applications.


Assuntos
Antibacterianos/farmacologia , Derivados de Benzeno/farmacologia , Compostos de Amônio Quaternário/farmacologia , Tensoativos/farmacologia , Antibacterianos/síntese química , Bacillus cereus/efeitos dos fármacos , Bacillus cereus/crescimento & desenvolvimento , Derivados de Benzeno/síntese química , Brometos/química , Coloides , Sinergismo Farmacológico , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Floculação , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Compostos de Amônio Quaternário/síntese química , Compostos de Amônio Quaternário/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Streptococcus agalactiae/efeitos dos fármacos , Streptococcus agalactiae/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tensoativos/síntese química , Temperatura , Termodinâmica
8.
Biophys Chem ; 307: 107165, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38309218

RESUMO

A major hallmark of Alzheimer's disease is the accumulation of aggregated amyloid ß peptide (Aß) in the brain. Here we develop a solubility assay for proteins and measure the solubility of Aß40. In brief, the method utilizes 96-well filter plates to separate monomeric Aß from aggregated Aß, and the small species are quantified with the amine reactive dye o-phthalaldehyde (OPA). This procedure ensures that solubility is measured for unlabeled species, and makes the assay high-throughput and inexpensive. We demonstrate that the filter plates successfully separate fibrils from monomer, with negligible monomer adsorption, and that OPA can quantify Aß peptides in a concentration range from 40 nM to 20 µM. We also show that adding a methionine residue to the N-terminus of Aß1-40 decreases the solubility by <3-fold. The method will facilitate further solubility studies, and contribute to the understanding of the thermodynamics of amyloid fibril formation.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Humanos , Peptídeos beta-Amiloides/química , Fragmentos de Peptídeos/química , Solubilidade , Doença de Alzheimer/metabolismo , Termodinâmica , Amiloide/química
9.
Nanomedicine ; 9(8): 1203-13, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23747739

RESUMO

Fully supramolecular dendrosomes (FSD) as bi-phase drug delivery systems are reported in this work. For preparation of FSD, amphiphilic linear-dendritic supramolecular systems (ALDSS) have been synthesized by host-guest interactions between hyperbranched polyglycerol having ß-cyclodextrin core and bi-chain polycaprolactone (BPCL) with a fluorescine focal point. Self-assembly of ALDSS in aqueous solutions led to FSD. They were able to encapsulate paclitaxel with a high loading capacity. The dendrosome-based drug delivery systems were highly sensitive to pH and temperature. They were stable at 20-37 °C and pH7-8, but dissociated and released drug at temperatures lower than 20 °C or higher than 37 °C and pH lower than 7 quickly. Dissociation of FSD building blocks by temperature or pH resulted in inclusion complexes between the released drugs and polyglycerol as the secondary drug delivery system. FROM THE CLINICAL EDITOR: This paper reports on the development of a pH- (below 7) and temperature- (below 20 °C or above 37 °C) sensitive delivery system using supramolecular dendrosomes for more specific delivery and release of drugs using paclitaxel as a model.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Preparações de Ação Retardada/química , Glicerol/química , Paclitaxel/administração & dosagem , Poliésteres/química , Polímeros/química , beta-Ciclodextrinas/química , Sistemas de Liberação de Medicamentos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Temperatura
10.
Nanomaterials (Basel) ; 13(6)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36985966

RESUMO

OBJECTIVES: This study was aimed at the investigation of the supramolecular systems based on cationic surfactants bearing cyclic head groups (imidazolium and pyrrolidinium) and polyanions (polyacrylic acid (PAA) and human serum albumin (HSA)), and factors governing their structural behavior to create functional nanosystems with controlled properties. Research hypothesis. Mixed PE-surfactant complexes based on oppositely charged species are characterized by multifactor behavior strongly affected by the nature of both components. It was expected that the transition from a single surfactant solution to an admixture with PE might provide synergetic effects on structural characteristics and functional activity. To test this assumption, the concentration thresholds of aggregation, dimensional and charge characteristics, and solubilization capacity of amphiphiles in the presence of PEs have been determined by tensiometry, fluorescence and UV-visible spectroscopy, and dynamic and electrophoretic light scattering. RESULTS: The formation of mixed surfactant-PAA aggregates with a hydrodynamic diameter of 100-180 nm has been shown. Polyanion additives led to a decrease in the critical micelle concentration of surfactants by two orders of magnitude (from 1 mM to 0.01 mM). A gradual increase in the zeta potential of HAS-surfactant systems from negative to positive value indicates that the electrostatic mechanism contributes to the binding of components. Additionally, 3D and conventional fluorescence spectroscopy showed that imidazolium surfactant had little effect on HSA conformation, and component binding occurs due to hydrogen bonding and Van der Waals interactions through the tryptophan amino acid residue of the protein. Surfactant-polyanion nanostructures improve the solubility of lipophilic medicines such as Warfarin, Amphotericin B, and Meloxicam. PERSPECTIVES: Surfactant-PE composition demonstrated beneficial solubilization activity and can be recommended for the construction of nanocontainers for hydrophobic drugs, with their efficacy tuned by the variation in surfactant head group and the nature of polyanions.

11.
Int J Pharm X ; 4: 100128, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36204592

RESUMO

NFL-TBS.40-63 peptide is a recently discovered peptide derived from the light neurofilament chain (NFL). In this study, we demonstrated that the Biotinylated-NFL-peptide (BIOT-NFL) can spontaneously self-assemble into well-organized nanofibers (approximately 5 nm width and several micrometers in length) in several solutions, whereas the typical self-assembly was not systematically observed from other peptides with or without coupling. The critical aggregation concentration that allows the BIOT-NFL-peptide to aggregate and auto associate was determined at 10-4 mol/L by surface tension measurements. X-ray scattering of BIOT-NFL-peptide also demonstrated its beta-sheet structure that can facilitate the intermolecular interactions involved in the self-assembly process. The possible disassembly of self-assembled BIOT-NFL-peptide-nanofibers was examined via a dialysis membrane study. We further investigated the interaction between nanofibers formed by BIOT-NFL-peptide and gold nanoparticles. Interestingly, a strong interaction was demonstrated between these nanoparticles and BIOT-NFL-peptide resulted in the formation of BIOT-NFL-peptide-nanofibers grandly decorated by gold nanoparticles. Finally, we investigated the internalization of gold nanoparticles coupled with BIOT-NFL-nanofibers into F98 rat glioblastoma cells, which was increased compared to the non-coupled control gold nanoparticles. All these results indicate that this peptide could be a promising therapeutic agent for targeted delivery.

12.
ACS Appl Mater Interfaces ; 13(36): 43290-43300, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34464079

RESUMO

We report the first successful combination of three distinct high-throughput techniques to deliver the accelerated design, synthesis, and property screening of a library of novel, bio-instructive, polymeric, comb-graft surfactants. These three-dimensional, surface-active materials were successfully used to control the surface properties of particles by forming a unimolecular deep layer on the surface of the particles via microfluidic processing. This strategy deliberately utilizes the surfactant to both create the stable particles and deliver a desired cell-instructive behavior. Therefore, these specifically designed, highly functional surfactants are critical to promoting a desired cell response. This library contained surfactants constructed from 20 molecularly distinct (meth)acrylic monomers, which had been pre-identified by HT screening to exhibit specific, varied, and desirable bacterial biofilm inhibitory responses. The surfactant's self-assembly properties in water were assessed by developing a novel, fully automated, HT method to determine the critical aggregation concentration. These values were used as the input data to a computational-based evaluation of the key molecular descriptors that dictated aggregation behavior. Thus, this combination of HT techniques facilitated the rapid design, generation, and evaluation of further novel, highly functional, cell-instructive surfaces by application of designed surfactants possessing complex molecular architectures.


Assuntos
Metacrilatos/química , Polietilenoglicóis/química , Bibliotecas de Moléculas Pequenas/química , Tensoativos/química , Ensaios de Triagem em Larga Escala , Aprendizado de Máquina , Metacrilatos/síntese química , Micelas , Modelos Químicos , Transição de Fase , Polietilenoglicóis/síntese química , Polimerização , Bibliotecas de Moléculas Pequenas/síntese química , Tensoativos/síntese química
13.
Methods Mol Biol ; 2207: 35-43, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33113126

RESUMO

Permeation technique is used to study molecular aggregation in aqueous solutions including formation of cyclodextrin guest/host aggregates. Since only guest molecules, host molecules and guest/host aggregates that are smaller than the pore size of a given semipermeable membrane are able to permeate through the membrane, negative deviation of permeation profiles indicates formation of guest/host aggregates or self-aggregates. This chapter describes how the method is used to detect formation of nano-sized aggregates and to determine the critical aggregation concentration (cac) from permeation profiles of a guest molecule.


Assuntos
Ciclodextrinas/química , Membranas Artificiais , Química Farmacêutica , Permeabilidade , Solubilidade
14.
Eur J Pharm Biopharm ; 166: 19-29, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34052430

RESUMO

The efficient association and controlled release of hydrophilic and aromatic low molecular-weight drugs (HALMD) still remains a challenge due to their relatively weak interactions with excipients and strong affinity to water. Considering that a wide variety of drugs to treat chronic diseases are HALMD, their inclusion in polymeric nanoparticles (NPs) constitutes an attractive possibility by providing to these drugs with controllable physiochemical properties, preventing crisis episodes, decreasing dose-dependent side effects and promoting therapeutic adhesiveness. However, the strong interaction of HALMD with the aqueous medium jeopardizes their encapsulation and controlled release. In this work, the role of the self-assembly tendency of HALMD on their association with the aromatic excipient poly(sodium 4-styrensulfonate) (PSS) to form NPs is studied. For this aim, the widely used drugs amitriptyline (AMT), promethazine (PMZ), and chlorpheniramine (CPM) are selected due to their well described critical aggregation concentration (cac) (36 mM for AMT, 36 mM for PMZ, and 69.5 mM for CPM). These drugs undergo aromatic-aromatic interactions with the polymer, which stabilize their mutual binding, as seen by NMR. The simple mixing of solutions of opposite charged molecules (drug + PSS) allowed obtaining NPs. Importantly, comparing the three drugs, the formation of NPs occurred at significantly lower absolute concentration and significantly lower drug/polymer ratio as the cac takes lower values, indicating a stronger binding to the polymer, as also deduced from the respective drug/polymer dissociation constant values. In addition, the number of formed NPs is similar for all formulations, even though a much lower concentration of the drug and polymer is present in systems comprising lower cac. The obtained NPs are spheroidal and present size between 100 and 160 nm, low polydispersity (≤0.3) and negative zeta potential (from -30 to -60 mV). The association efficiency reaches values ≥ 83% and drug loading could achieve values up to 68% (never evidenced before for systems comprising HALMD). In addition, drug release studies are also significantly influenced by cac, providing more prolonged release for AMT and PMZ (lower cac), whose delivery profiles adjust to the Korsmeyer-Peppas equation. As a novelty of this work, a synergic contribution of drug self-association tendency and aromatic-aromatic interaction between the drug and polymers is highlighted, a fact that could be crucial for the rational design and development of efficient drug delivery systems.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Excipientes , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Composição de Medicamentos/métodos , Excipientes/química , Excipientes/farmacologia , Humanos , Peso Molecular , Nanopartículas/química , Nanopartículas/uso terapêutico , Tamanho da Partícula , Farmacocinética , Polímeros/química , Polímeros/farmacologia , Solubilidade
15.
Colloids Surf B Biointerfaces ; 204: 111795, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33945967

RESUMO

Stearic acid (SA) and oleic acid (OA) which are inherently existing fatty acids (FAs) in the body can alter cell membrane function and interact with each other. However, discrepancies arise as to whether these effects are beneficial or harmful on the body. To resolve this ambiguity, there is a dire need to study how FAs can affect the etiology of diseases and their treatment. In this study, we aimed to investigate long chain FAs aggregation behaviors and their effects on membrane integrity and cell viability. We determined the critical aggregation concentration (CAC) of SA and OA (1110 µM and 300 µM, respectively which were less amount than that used in nanocarriers). In TEM images, hexagonal overlapped or fused structures of SA were seen, whereas quite small spherical clusters of OA were obtained. Membrane integrity assessments demonstrated that SA and OA at their own CAC and below could crack the lipid junctions on membrane mimicking systems. Moreover, they completely disrupt the membrane integrity above the CAC at pH 7.2. Cell viabilities on various cell lines were assessed after exposed to SA or OA aggregates. SA was more aggressive than OA on cell death in all cell lines. The effect of SA on PC3 cell lines was in a concentration-dependent manner. The effect of SA above CAC boosted the inhibition of cell viability. Furthermore, OA showed a proliferation effect on PC3 cells. Consequently, the aggregation behavior of FAs should be considered as a noteworthy factor in physiological functions.


Assuntos
Ácidos Graxos , Ácidos Esteáricos , Morte Celular , Membrana Celular , Sobrevivência Celular , Ácido Oleico/farmacologia
16.
Carbohydr Polym ; 267: 118183, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119151

RESUMO

Fluorescence probing was used to study hydrophobic interactions of galactomannan (GM) obtained from fenugreek gum (FG), guar gum (GG), and locust bean gum (LBG) at different M/G ratios. The I1/I3 ratio of pyrene changed from 1.73 to 1.29, 1.22, and 1.29 for FG, GG and LBG, respectively, as the concentration of GM increased from 0.01 to 8.0 g/L at 30 °C. The critical aggregation concentration of FG, GG, and LBG increased from 1.04 to 3.84 g/L, 1.15 to 3.73 g/L, and 0.94 to 3.63 g/L, respectively, as temperature increased from 10 to 70 °C. Addition of Na2SO4 and NaSCN increased the I1/I3 ratio in dilute solution, but reduced it in semi-dilute solution, whereas adding urea reduced I1/I3 in dilute solution but increased it in semi-dilute solution. These results indicated that the CAC of GM, polarity and number of hydrophobic microdomains were highly dependent on the M/G ratio and galactose distribution.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Mananas/química , Sequência de Carboidratos , Corantes Fluorescentes/química , Galactanos/química , Galactose/análogos & derivados , Gomas Vegetais/química , Pirenos/química , Sulfatos/química , Temperatura , Tiocianatos/química , Trigonella/química , Ureia/química
17.
Carbohydr Polym ; 251: 116997, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142566

RESUMO

New amphiphilic derivatives of kappa-carrageenan (KC) were synthesized by hydrophobic modification with octyl chloride. Two different methods based on microwave and conventional heating were used. All KC derivatives (KCRs) were characterized by different techniques. The FT-IR and 1HNMR studies demonstrated that the octyl groups were effectively grafted onto KC backbone and confirmed that the derivative KCRMM, obtained by microwave heating, presented a higher degree of substitution (DS = 0.77) compared to KCRCM (0.45). The amphiphilic character investigation also revealed that KCRMM exhibited a lower critical aggregation concentration (CAC) value of 0.13% w/v than KCRCM (0.15%). Furthermore, KCRs greatly improved the stability of oil/water emulsions as the droplet size decreased with increasing DS. Unlike the conventional heating method, novel derivatives with a higher DS, greater amphiphilic character, and an improved emulsifying power were obtained by microwave-assisted synthesis. These derivatives could potentially be used in food, cosmetics, or as excipients in pharmaceutics.


Assuntos
Carragenina/síntese química , Excipientes/síntese química , Carragenina/química , Carragenina/ultraestrutura , Estabilidade de Medicamentos , Difusão Dinâmica da Luz , Excipientes/química , Temperatura Alta , Humanos , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Peso Molecular , Tamanho da Partícula , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos , Termodinâmica , Difração de Raios X
18.
Carbohydr Polym ; 238: 116199, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32299569

RESUMO

Octenyl-succinylated inulins (OSA-inulin) were synthesized in aqueous solutions using inulin with varying degrees of polymerization (DP). They were characterized using 1H NMR and FTIR and their degrees of substitution were determined. All the samples formed micellar aggregates in aqueous solution above a critical aggregation concentration (CAC) and solubilized beta-carotene. The amount of beta carotene solubilized within the micelles ranged from 12 to 25 mg/g of OSA-inulin and depended on the inulin molar mass. Dynamic light scattering showed that the aggregates, with and without dissolved beta-carotene, were ∼10-15 nm in size and this was confirmed by Transmission Electron Microscopy which also indicated that the micelles had a globular shape. OSA-inulin particles containing encapsulated beta-carotene were produced by freeze-drying. The encapsulated beta-carotene was not released from the freeze-dried particles when introduced into simulated gastric fluid at pH 2.5 but was readily released in simulated small intestinal fluid at pH 7. The results demonstrate the potential application of OSA-inulin in the encapsulation, dissolution and targeted delivery of hydrophobic drug molecules for nutraceutical, pharmaceutical and medical applications.


Assuntos
Preparações de Ação Retardada , Portadores de Fármacos , Inulina/química , Amido/análogos & derivados , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/química , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Micelas , Amido/síntese química , Amido/química , beta Caroteno
19.
Curr Protoc Chem Biol ; 12(1): e78, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32150343

RESUMO

Small-molecule drug discovery can be hindered by the formation of aggregates that act as non-selective inhibitors of drug targets. Such aggregates appear as false positives in high-throughput screening campaigns and can bedevil structure-activity relationships during compound optimization. Protocols are described for resonant waveguide grating (RWG) and dynamic light scattering (DLS) as microplate-based high-throughput approaches to identify compound aggregation. Resonant waveguide grating and dynamic light scattering give equivalent results for the compound test set, as assessed with Bland-Altman analysis. © 2019 The Authors. Basic Protocol 1: Resonant waveguide grating (RWG) in 384-well or 1536-well plate format to detect compound aggregation Basic Protocol 2: Dynamic light scattering (DLS) in 384-well plate format to detect compound aggregation.


Assuntos
Artefatos , Ensaios de Triagem em Larga Escala/métodos , Preparações Farmacêuticas/química , Bibliotecas de Moléculas Pequenas/análise , Bibliotecas de Moléculas Pequenas/química , Descoberta de Drogas/métodos , Difusão Dinâmica da Luz
20.
Polymers (Basel) ; 12(9)2020 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-32846926

RESUMO

Thermoresponsive poly(glycidyl ether) brushes can be grafted to applied tissue culture substrates and used for the fabrication of primary human cell sheets. The self-assembly of such brushes is achieved via the directed physical adsorption and subsequent UV immobilization of block copolymers equipped with a short, photo-reactive benzophenone-based anchor block. Depending on the chemistry and hydrophobicity of the benzophenone anchor, we demonstrate that such block copolymers exhibit distinct thermoresponsive properties and aggregation behaviors in water. Independent on the block copolymer composition, we developed a versatile grafting-to process which allows the fabrication of poly(glycidyl ether) brushes on various tissue culture substrates from dilute aqueous-ethanolic solution. The viability of this process crucially depends on the chemistry and hydrophobicity of, both, benzophenone-based anchor block and substrate material. Utilizing these insights, we were able to manufacture thermoresponsive poly(glycidyl ether) brushes on moderately hydrophobic polystyrene and polycarbonate as well as on rather hydrophilic polyethylene terephthalate and tissue culture-treated polystyrene substrates. We further show that the temperature-dependent switchability of the brush coatings is not only dependent on the cloud point temperature of the block copolymers, but also markedly governed by the hydrophobicity of the surface-bound benzophenone anchor and the subjacent substrate material. Our findings demonstrate that the design of amphiphilic thermoresponsive block copolymers is crucial for their phase transition characteristics in solution and on surfaces.

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