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1.
Artigo em Inglês | MEDLINE | ID: mdl-39344136

RESUMO

As the societal issue of increasing global illicit drug usage emerges, there is a growing demand for more portable and versatile drug detectors. Traditional drug analysis techniques such as gas chromatography (GC), liquid chromatography (LC), and Fourier transform infrared spectroscopy (FTIR) face significant challenges in adapting to diverse real-world applications due to their size, cost, and power requirements. While advancements have been made in the development of on-site drug detection methods such as fluorescence, stereoresonance energy transfer (FRET), colorimetric, electrochemical sensing, and lateral flow assays (LFAs), their reliance on specific reactive materials poses limitations in effectively detecting a wide range of narcotics. Therefore, this study proposes the development of specialized microcolumns with optimized stationary phases for next-generation portable microfabricated GC-based narcotic detectors. The stationary phase consists of a hybrid gel incorporating the ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and OV-1. The stationary phase not only enhances interactions between drug analytes but also demonstrates improved separation characteristics among various narcotic substances. Additionally, the principles of the separation results were validated through density functional theory (DFT) analysis, and the effective separation of over seven types of narcotics was demonstrated through temperature optimization. This research lays the groundwork for the advancement of next-generation portable drug analyzers, offering significant potential in the field.

2.
Food Chem X ; 21: 101151, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38312487

RESUMO

The influence of ultrasonic processing on the physicochemical characteristics, microstructure, and intermolecular forces of the hybrid gels obtained by heating the mixtures of different ratios of salted ovalbumin (SOVA)-cooked soybean protein isolate (CSPI) was investigated. With the growth of SOVA addition, ζ-potential in absolute value, cohesiveness, water-holding capacity (WHC), surface hydrophobicity, and the content of soluble protein of the hybrid gels decreased (P < 0.05), while the hardness, T2 relaxation time of the hybrid gels increased (P < 0.05). And the compactness of the network structure of the hybrid gel increased with the increase of SOVA addition. After being treated with ultrasound, significant increases (P < 0.05) of ζ-potential in absolute value, cohesiveness, WHC, and surface hydrophobicity of the hybrid gels were observed. In general, ultrasonic processing is one of the effective means to improve the gel properties of SOVA-CSPI hybrid gels.

3.
Gels ; 10(1)2024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38247796

RESUMO

An excellent oil-water interface is one of the prerequisites for effective lipase catalysis. Therefore, this study aimed to improve lipase activity in terms of catalytic interface optimization. A novel approach for constructing oil-water interfaces was proposed. The structural similarity and the hydrophilic differences between polyvinyl pyrrolidone gel-fiber membranes (GFMs) and poly(lauryl methacrylate) (PLMA) organogel inspired us to hybridize the two to form PVP/PLMA hybrid gel-fiber membranes (HGFMs) based on electrospinning and gelation. The prepared PVP/PLMA-HGFMs were capable of being adopted as novel carriers for lipase catalysis due to their ability to swell both in the aqueous phase (swelling ratio = 187.5%) and the organic phase (swelling ratio = 40.5%). Additionally, Confocal laser scanning microscopy (CLSM) results showed that abundant network pores inside the carriers enabled numerous effective microscopic oil-water interfaces. The catalytic activity of Burkholderia cepacia lipase (BCL) in PVP/PLMA-HGFMs ranged between 1.21 and 8.70 times that of the control ("oil-up/water-down" system) under different experimental conditions. Meanwhile, PVP/PLMA-HGFMs increased lipase activity by about eight times at -20 °C and had good application characteristics at extreme pH conditions.

4.
Food Res Int ; 176: 113784, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38163701

RESUMO

The effect of the cold-set and heat-set gelling mechanism of whey protein isolate on bigel production was assessed. For this purpose, hydrogel phase was produced with whey protein isolated (10 % w/v) and for oleogel sunflower oil and glycerol monostearate (7.5 % w/v) were used. Bigels were produced by hot emulsification of different hydrogel:oleogel ratios (from 90:10 up to 10:90). For cold-set bigels (CSB) NaCl (200 mM) was added to the aqueous phase prior to the emulsification and the emulsion was cooled to promote the 3D network formation. On the other hand, heat-set bigels (HSB) were produced by heating the emulsion (80 °C, 60 min). Bigels were evaluated through microscopy, FTIR, thermal and texture analyzes. Results showed that depending on the hydrogel:oleogel ratio and gelling mechanism different structures organization were obtained. CSB were more organized, showing that the rate of gelation was the mechanism responsible for the structure. However, for HSB the heat treatment destabilized the emulsion and disorganized structures were observed for high oleogel content. FTIR corroborates the visual observation and showed that the arrangement was purely physical. In addition, the structural arrangement led to different mechanical properties. In general, HSB produced gels with rubber-like behavior, higher elasticity modulus and the presence of a breaking point. In contrast, CSB behaves as squeezing gel, with no breaking point and lower values of elasticity modulus. Moreover, for O/W bigels the dispersed oleogel particles disrupted the WPI network decreasing the gel strength in comparison to pure hydrogels. However, for systems where oleogel was the continuous phase, the gel strength was recovered due to the metastable and dynamic character of these systems. Thus, results showed that the gelling mechanism of the protein exerted an effect on the physical properties of bigels. In addition, the mechanical properties also can be modulated according to the bigel composition, allowing its application in products with different sensorial characteristics.


Assuntos
Hidrogéis , Compostos Orgânicos , Proteínas do Soro do Leite , Emulsões , Hidrogéis/química , Compostos Orgânicos/química
5.
J Sci Food Agric ; 104(6): 3749-3756, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38234140

RESUMO

BACKGROUND: Laboratory scale experiments have shown that curdlan and gellan gum gelled together as curdlan/gellan gum (CG) hybrid gels showed better gel properties than the individual curdlan and gellan gum. In this study, CG and black wolfberry anthocyanin (BWA), CG and maltitol (ML) hybrid gels were constructed using CG hybrid gel as matrix. The effects of BWA or ML on the gel properties and microstructure of CG hybrid gels were investigated and a confectionery gel was developed. RESULTS: The presence of BWA increased the storage modulus (G') value of CG at 0.1 Hz, whereas ML had little effect on the G' value of CG. The addition of BWA (5 g L-1 ) and ML (0.3 mol L-1 ) increased the melting and gelling temperatures of CG hybrid gels to 42.4 °C and 34.1 °C and 44.2 °C and 33.2 °C, respectively. Meanwhile, the relaxation time T22 in CG-ML and CG-BWA hybrid gels was reduced to 91.96 and 410.27 ms, indicating the strong binding between BWA and CG, ML and CG. The hydrogen bond interaction between BWA or ML and CG was confirmed by the shift in the hydroxyl stretching vibration peak. Moreover, the microstructures of CG-ML and CG-BWA hybrid gels were denser than that of CG. In addition, confectionery gel containing CG-BWA-ML has good chewing properties. CONCLUSION: These results indicated that the incorporation of BWA or ML could improve the structure of CG hybrid gels and assign a sustainability potential for the development of confectionery gels based on CG complex. © 2024 Society of Chemical Industry.


Assuntos
Lycium , Maltose/análogos & derivados , Álcoois Açúcares , beta-Glucanas , Antocianinas , Polissacarídeos Bacterianos/química , Géis/química , Reologia
6.
Bioeng Transl Med ; 8(5): e10470, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37693066

RESUMO

Indocyanine green (ICG), glucose oxidase (GOx), and copper(II) sulfate (Cu)-installed hybrid gel based on organic nanorod (cellulose nanocrystal [CNC]) and inorganic nanodisk (Laponite [LAP]) was developed to perform a combination of starvation therapy (ST), chemodynamic therapy (CDT), and photothermal therapy (PTT) for localized cancers. A hybrid CNC/LAP network with a nematic phase was designed to enable instant gelation, controlled viscoelasticity, syringe injectability, and longer in vivo retention. Moreover, ICG was introduced into the CNC/LAP gel system to induce hyperthermia of tumor tissue, amplifying the CDT effect; GOx was used for glucose deprivation (related to the Warburg effect); and Cu was introduced for hydroxyl radical generation (based on Fenton-like chemistry) and cellular glutathione (GSH) degradation in cancer cells. The ICG/GOx/Cu-installed CNC/LAP gel in combination with near-infrared (NIR) laser realized improved antiproliferation, cellular reactive oxygen species (ROS) generation, cellular GSH degradation, and apoptosis induction in colorectal cancer (CT-26) cells. In addition, local injection of the CNC/ICG/GOx/Cu/LAP gel into the implanted CT-26 tumor while irradiating it with NIR laser provided strong tumor growth suppression effects. In conclusion, the designed hybrid nanorod/nanodisk gel network can be efficiently applied to the local PTT/ST/CDT of cancer cells.

7.
Polymers (Basel) ; 15(12)2023 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-37376290

RESUMO

Polyampholyte (PA) hydrogels are randomly copolymerized from anionic and cationic monomers, showing good mechanical properties owing to the existence of numerous ionic bonds in the networks. However, relatively tough PA gels can be synthesized successfully only at high monomer concentrations (CM), where relatively strong chain entanglements exist to stabilize the primary supramolecular networks. This study aims to toughen weak PA gels with relatively weak primary topological entanglements (at relatively low CM) via a secondary equilibrium approach. According to this approach, an as-prepared PA gel is first dialyzed in a FeCl3 solution to reach a swelling equilibrium and then dialyzed in sufficient deionized water to remove excess free ions to achieve a new equilibrium, resulting in the modified PA gels. It is proved that the modified PA gels are eventually constructed by both ionic and metal coordination bonds, which could synergistically enhance the chain interactions and enable the network toughening. Systematic studies indicate that both CM and FeCl3 concentration (CFeCl3) influence the enhancement effectiveness of the modified PA gels, although all the gels could be dramatically enhanced. The mechanical properties of the modified PA gel could be optimized at CM = 2.0 M and CFeCl3 = 0.3 M, where the Young's modulus, tensile fracture strength, and work of tension are improved by 1800%, 600%, and 820%, respectively, comparing to these of the original PA gel. By selecting a different PA gel system and diverse metal ions (i.e., Al3+, Mg2+, Ca2+), we further prove that the proposed approach is generally appliable. A theoretical model is used to understand the toughening mechanism. This work well extends the simple yet general approach for the toughening of weak PA gels with relatively weak chain entanglements.

8.
Molecules ; 28(5)2023 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-36903388

RESUMO

With the development of laser technology, the research of novel laser protection materials is of great significance. In this work, dispersible siloxene nanosheets (SiNSs) with a thickness of about 1.5 nm are prepared by the top-down topological reaction method. Based on the Z-scan and optical limiting testing under the visible-near IR ranges nanosecond laser, the broad-band nonlinear optical properties of the SiNSs and their hybrid gel glasses are investigated. The results show that the SiNSs have outstanding nonlinear optical properties. Meanwhile, the SiNSs hybrid gel glasses also exhibit high transmittance and excellent optical limiting capabilities. It demonstrates that SiNSs are promising materials for broad-band nonlinear optical limiting and even have potential applications in optoelectronics.

9.
J Agric Food Chem ; 71(4): 2113-2123, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36688519

RESUMO

According to the "interfacial activation" mechanism, constructing a sufficient interface is the key strategy for lipase-catalytic system designing. Based on the "infinite interface in finite three-dimensional space" logic, in the current study, poly(N,N-dimethylacrylamide) (PDMA)-polybutyl methacrylate (PBMA) hybrid gels were prepared by a two-step crosslinking strategy, subsequently constructed as lipase-interfacial catalytic systems. The results confirm that the PDMA-PBMA hybrid gels with "networks in pores" structures could swell both the aqueous phase and organic phase. The balance between water swelling and isooctane swelling, hybrid gel space (height control), and the lipase entry manner significantly affect the interface construction and consequently the catalytic efficiency. The enzyme-substrate contact rate affected by swelling leads to three catalytic stages. Considering the spatial barrier and distribution of lipases, a potential high-performance lipase reactor can be assembled from small-size, lamellar-like, and porous hybrid gels. The reactors also show good time storage and low temperature tolerance.


Assuntos
Hidrogéis , Lipase , Lipase/química , Ácidos Polimetacrílicos , Catálise
10.
Int J Biol Macromol ; 232: 123098, 2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-36681219

RESUMO

Hazardous effluents from textile industries being major contributors of water pollution and impose potential adverse effects on environment. In present study, Fe3O4 embedded oxidized Sterculia gum/Gelatin hybrid matrix have been fabricated and evaluated for enrichment of methyl orange (MO) and methylene blue (MB). Newly synthesized matrix was characterized through powdered XRD, FTIR, FESEM, TEM and TGA. Integrated nanoparticles improved dye enrichment and facilitated removal of matrix from the aqueous solution under the influence of magnetic field. Influence of various reaction parameters viz.: contact time, adsorbent dose, initial dye concentration, temperature & pH of the adsorption medium on dye enrichment have been evaluated. Maximum adsorption (90 % and 88 % for MO and MB respectively) has been achieved. Langmuir, Freundlich and Tempkin adsorption isotherms have been evaluated. Experimental results validate well fitted Freundlich isotherm for MO and Temkin isotherm for MB. Adsorption kinetics has been analyzed through Pseudo first order, second order kinetic and intra particle diffusion models. Adsorption of both dyes was best explained via pseudo second order kinetic model. Negative value of Gibb's free energy change (-26.487 KJ mol -1 and - 24.262 KJ mol -1) for MB and MO at 303 K was an indication of spontaneity of the reaction.


Assuntos
Sterculia , Poluentes Químicos da Água , Corantes/química , Gelatina , Adsorção , Poluentes Químicos da Água/química , Goma de Karaya , Cinética , Azul de Metileno/química , Concentração de Íons de Hidrogênio
11.
Gels ; 8(12)2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-36547336

RESUMO

Efficient lipase catalysis requires sufficient oil-water interface engineered through structural design. Inspired by the architectural features of fabrics, a novel lipase-membrane catalytic system with interwoven polyacrylic acid (PAA) gel fibers and polyvinyl pyrrolidone (PVP) gel fibers was developed in this study by using double-needle electrospinning and gelation. It has been demonstrated that PAA/PVP hybrid gel fiber membranes (HGFMs) have a high swelling capacity for both water and oil phases, which created numerous discontinuous oil-water contact surface units in limited space of HGFMs, consequently forming effective interfacial catalytic systems. Volume competition between the water and oil phases suggests that balancing the proportions of these phases is very important for effective construction of oil-water interfaces and conditioning catalysis. Regulation of multiple factors of PAA/PVP HGFMs resulted in a catalytic efficiency of up to 2.1 times that of a macroscopic "oil-up/water-down" system (room temperature, pH = 7), and 2.9 times when three membranes are superimposed, as well as excellent pH and temperature stability. HGFMs were stacked to build a high-performing catalytic performance reactor. We expect that this study will be a beneficial exploration for expanding the lipase catalytic system.

12.
Int J Biol Macromol ; 223(Pt A): 1158-1179, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36375674

RESUMO

The current work is focused on the preparation of protein-mediated poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) copolymer as a self-template for in situ synthesis of hybrid gels. Gelatin, collagen, biotin, and l-arginine were used to create hybrid materials with adjustable swelling and elastic properties. Hybrid cryogels tended to swell more than hybrid hydrogels due to their porous nature. Collaged-doped cryogels had the highest swelling, whereas gelatin-doped hybrids showed enhanced elastic modulus. All hybrid gels exhibited pH-sensitive swelling to controlled release applications depending on the degree of protonation of NH2 and COOH groups in the side chains. At low pH conditions, hybrid cryogels exhibited a higher swelling tendency compared to hydrogels. Ion-stimulus-response of hybrid gels was studied to evaluate the effect of salt concentration and features of ambient ions on swelling. Depending on the polyelectrolytic or polyampholytic nature, the extent of swelling in NaCl and KCl solutions varied according to the charge distribution in the network chains. Hybrid gels showed excellent adsorption performance for methyl orange by the presence of epoxy, hydroxyl groups, amino and carboxyl groups providing sufficient active sites. Adsorption capacity of hybrid cryogels is higher than that of hydrogels. The removal rate 97/%, reached an equilibrium state in a short period, suggested that collagen-doped hybrid cryogels have a potential application to remove dyestuff from wastewater. In relation to the decrease of methyl orange concentration in solution, adsorption process followed pseudo-second-order kinetic model. Avrami model has provided a better experimental-calculated fit and adsorption thermodynamics analysis indicated that the adsorption was a spontaneous process with a negative standard free energy. The characteristic findings from this research will provide insights into the design and application of enoate-ester and protein-based combinations in the food, biomedical and cosmetic fields.


Assuntos
Criogéis , Ésteres , Criogéis/química , Concentração de Íons de Hidrogênio , Compostos Azo , Adsorção , Géis
13.
Polymers (Basel) ; 14(12)2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35745976

RESUMO

The development of biorefineries brings the necessity of an efficient consumption of all sugars released from biomasses, including xylose. In addition, the presence of inhibitors in biomass hydrolysates is one of the main challenges in bioprocess feasibility. In this study, the application of Ca-alginate hybrid gels in the immobilization of xylose-consuming recombinant yeast was explored with the aim of improving the tolerance of inhibitors. The recombinant yeast Saccharomyces cerevisiae GSE16-T18SI.1 (T18) was immobilized in Ca-alginate and Ca-alginate-chitosan hybrid beads, and its performance on xylose fermentation was evaluated in terms of tolerance to different acetic acid concentrations (0-12 g/L) and repeated batches of crude sugarcane bagasse hemicellulose hydrolysate. The use of the hybrid gel improved yeast performance in the presence of 12 g/L of acetic acid, achieving 1.13 g/L/h of productivity and reaching 75% of the theoretical ethanol yield, with an improvement of 32% in the xylose consumption rate (1:1 Vbeads/Vmedium, 35 °C, 150 rpm and pH 5.2). The use of hybrid alginate-chitosan gel also led to better yeast performance at crude hydrolysate, yielding one more batch than the pure-alginate beads. These results demonstrate the potential of a hybrid gel as an approach that could increase 2G ethanol productivity and allow cell recycling for a longer period.

14.
Gels ; 8(2)2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35200450

RESUMO

Bottom-up approaches in solutions enable the low-temperature preparation of hybrid thin films suitable for printable transparent and flexible electronic devices. We report the obtainment of new transparent PMMA/ZrO2 nanostructured -building blocks (nBBs) hybrid thin films (61-75 nm) by a modified sol-gel method using zirconium ethoxide, Zr(OEt)4, and 3-methacryloxypropyl trimethoxysilane (MPS) as a coupling agent and methylmethacrylate monomer (MMA). The effect of low-temperature and UV irradiation on the nBBs gel films is discussed. The thermal behaviors of the hybrid sols and as-deposed gel films were investigated by modulated thermogravimetric (mTG) and differential scanning calorimetry (DSC) analysis. The chemical structure of the resulted films was elucidated by X-ray photoelectron (XPS), infrared (IR) and Raman spectroscopies. Their morphology and crystalline structure were observed by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and grazing incidence X-ray diffraction. The cured films show zirconia nanocrystallites of 2-4 nm in the hybrid matrix and different self-assembled structures for 160 °C or UV treatment; excellent dielectric behavior, with dielectric constant values within 6.7-17.9, depending on the Zr(OEt)4:MMA molar ratio, were obtained.

15.
Photochem Photobiol Sci ; 21(4): 545-555, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35195890

RESUMO

Photochromic materials can be used for modulation of the visible and infrared light transmittance for providing privacy or energy saving by blocking the heat. Titanium dioxide (TiO2) nanoparticles has been well reported as a promising photochromic material. However, a high photochromic response from TiO2 can be observed only when the nanoparticles are dispersed in a strong photogenerated hole scavenger at a liquid state, but polymer composites are less responsive due to lack of hole scavenging capability. However, it is intricate to apply suspensions in real window devices because of possible leaking. Here, we describe the preparation of TiO2 quantum dot (QD)-based gels from polyethylene glycol diacrylate (PEGDA), N,N-Dimethylformamide (DMF), and ethanol (EtOH). Photochromic gels with TiO2 contents (1-5 volume%) show performance comparable to their colloidal counterparts with capable of photodarkening within 30 min with a transmittance change ranging from 35.8 to 84.5% at 550 nm. These gels were capable of fully recovering the initial transmittance when not exposed to ultraviolet (UV) light within 3-8 h. The photochromic gel systems with ethanol shows reasonable stability by decreasing in transmittance recovery only by less than 10% in 10 cycles. A potential application for the developed photochromic gels can be photochromic windows.


Assuntos
Nanopartículas , Polietilenoglicóis , Etanol , Polímeros , Titânio
16.
Gels ; 7(4)2021 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-34940301

RESUMO

This study reports a strategy for developing a biohybrid complex based on a natural/synthetic polymer conjugate as a gel-type structure. Coupling synthetic polymers with natural compounds represents an important approach to generating gels with superior properties and with potential for biomedical applications. The study presents the preparation of hybrid gels with tunable characteristics by using a spiroacetal polymer and alginate as co-partners in different ratios. The new network formation was tested, and the structure was confirmed by FTIR and SEM techniques. The physical properties of the new gels, namely their thermal stability and swelling behavior, were investigated. The study showed that the increase in alginate content caused a smooth increase in thermal stability due to the additional crosslinking bridges that appeared. Moreover, increasing the content of the synthetic polymer in the structure of the gel network ensures a slower release of carvacrol, the encapsulated bioactive compound.

18.
Polymers (Basel) ; 11(6)2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31159458

RESUMO

Nano-sized one-dimensional metallo-organic polymers, characterized by the phenomenon of spin transition, are excellent candidates for advanced technological applications such as optical sensors, storage, and information processing devices. However, the main drawback of this type of polymers is their fragile mechanical properties, which hinders its processing and handling, and makes their practical use unfeasible. To overcome this problem, in this work, hybrid thermo-reversible gels are synthesized by combination of a metallo-organic polymer and isotactic polystyrene (iPS) in cis-decaline. A detailed investigation of the thermal and viscoelastic properties of the hybrid gels, in terms of iPS and metallo-organic polymer concentration is performed by means of differential scanning calorimetry and oscillatory rheology, respectively. From the analysis of the thermal properties, three transitions have been determined upon heating: Monotectic transition of the iPS gel, melting of the iPS gel, and melting of the metal-organic polymer gel, which suggest that the gels of the two polymers are formed independently in the hybrid gel, as long as the two polymers are in concentrations above the corresponding critical gelation concentrations. Results regarding viscoelastic properties and morphology confirmed that hybrid gels consisted of an interpenetrated network of polymer gels, formed by iPS and metallo-organic poymer gels growing independently.

19.
Nanomaterials (Basel) ; 7(11)2017 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-29135939

RESUMO

In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response and bioactive molecules release have been evaluated. At first, a slurry of Alg and α-TCP has been prepared using an ultrasonicator for the homogeneous distribution of α-TCP particles in the Alg network and to achieve adequate interfacial interaction between them. After that, CaCl2 solution has been added to the slurry so that ionic crosslinked gel (Alg-α-TCP) is formed. The developed hybrid gel has been physico-chemically characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and a swelling study. The SEM analysis depicted the presence of α-TCP micro-particles on the surface of the hybrid gel, while cross-section images signified that the α-TCP particles are fully embedded in the porous gel network. Different % swelling ratio at pH 4, 7 and 7.4 confirmed the pH responsiveness of the Alg-α-TCP gel. The hybrid gel having lower % α-TCP particles showed higher % swelling at pH 7.4. The hybrid gel demonstrated a faster release rate of bovine serum albumin (BSA), tetracycline (TCN) and dimethyloxalylglycine (DMOG) at pH 7.4 and for the grade having lower % α-TCP particles. The MC3T3 cells are viable inside the hybrid gel, while the rate of cell proliferation is higher at pH 7.4 compared to pH 7. The in vitro cytotoxicity analysis using thiazolyl blue tetrazolium bromide (MTT), bromodeoxyuridine (BrdU) and neutral red assays ascertained that the hybrid gel is non-toxic for MC3T3 cells. The experimental results implied that the non-toxic and biocompatible Alg-α-TCP hybrid gel could be used as scaffold in bone tissue engineering.

20.
Colloids Surf B Biointerfaces ; 145: 706-715, 2016 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-27289312

RESUMO

Ciprofloxacin is a broad-spectrum antibiotic associated with gastric and intestinal side effects after extended oral administration. Alginate is a biopolymer commonly employed in gel synthesis by ionotropic gelation, but unstable in the presence of biological metal-chelating compounds and/or under dried conditions. Kefiran is a microbial biopolymer able to form gels with the advantage of displaying antimicrobial activity. In the present study, kefiran-alginate gel microspheres were developed to encapsulate ciprofloxacin for antimicrobial controlled release and enhanced bactericidal effect against common pathogens. Scanning electron microscopy (SEM) analysis of the hybrid gel microspheres showed a spherical structure with a smoother surface compared to alginate gel matrices. In vitro release of ciprofloxacin from kefiran-alginate microspheres was less than 3.0% and 5.0% at pH 1.2 (stomach), and 5.0% and 25.0% at pH 7.4 (intestine) in 3 and 21h, respectively. Fourier transform infrared spectroscopy (FTIR) of ciprofloxacin-kefiran showed the displacement of typical bands of ciprofloxacin and kefiran, suggesting a cooperative interaction by hydrogen bridges between both molecules. Additionally, the thermal analysis of ciprofloxacin-kefiran showed a protective effect of the biopolymer against ciprofloxacin degradation at high temperatures. Finally, antimicrobial assays of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhymurium, and Staphylococcus aureus demonstrated the synergic effect between ciprofloxacin and kefiran against the tested microorganisms.


Assuntos
Alginatos/química , Antibacterianos/química , Antibacterianos/farmacologia , Ciprofloxacina/química , Ciprofloxacina/farmacologia , Microesferas , Polissacarídeos/química , Administração Oral , Sistemas de Liberação de Medicamentos , Escherichia coli/efeitos dos fármacos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Klebsiella pneumoniae/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
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