pH-responsive alginate-based hydrogels for protein delivery

Lima, Diego S.D.; Tenório‐Neto, Ernandes T.; Lima-Tenório, Michele K.; Guilherme, Marcos R.; Scariot, Débora B.; Nakamura, Celso V.; Muniz, Edvani C.; Rubira, Adley F.

doi:10.1016/j.molliq.2018.04.002

Cited by 80 publications

(24 citation statements)

References 21 publications

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“…[106]. Such polysaccharide matrices are loaded with active ingredients which are, by diffusion and pH related erosion, released in targeted tissues [107]. Release mechanisms of active compounds from different grades of alginate matrices at different acidity were investigated by Sriamornsak et al [108].…”

Section: Brown Algae Sulfated Polysaccharides As Drug Delivery Systemmentioning

confidence: 99%

Advanced Technologies for the Extraction of Marine Brown Algal Polysaccharides

et al. 2020

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Over the years, brown algae bioactive polysaccharides laminarin, alginate and fucoidan have been isolated and used in functional foods, cosmeceutical and pharmaceutical industries. The extraction process of these polysaccharides includes several complex and time-consuming steps and the correct adjustment of extraction parameters (e.g., time, temperature, power, pressure, solvent and sample to solvent ratio) greatly influences the yield, physical, chemical and biochemical properties as well as their biological activities. This review includes the most recent conventional procedures for brown algae polysaccharides extraction along with advanced extraction techniques (microwave-assisted extraction, ultrasound assisted extraction, pressurized liquid extraction and enzymes assisted extraction) which can effectively improve extraction process. The influence of these extraction techniques and their individual parameters on yield, chemical structure and biological activities from the most current literature is discussed, along with their potential for commercial applications as bioactive compounds and drug delivery systems.(APS) is determined by algae species however it is also influenced by other factors causing inter-species variation, e.g., growth location and harvesting season [8]. Vast structural variation between the APS therefore presents a challenge in terms of pre-treatments application, extraction techniques and optimization, characterization of isolated fractions and determination of their biological properties.Chemical structure and yield of APS isolated from marine macroalgae by conventional extraction (CE) techniques can be affected by various experimental conditions (pH, time, temperature, pressure, particle size, solvent, sample to solvent ratio, agitation speed etc.). In addition, different advanced techniques such as microwave assisted extraction (MAE), ultrasound assisted extraction (UAE), pressurized liquid extraction (PLE), enzyme-assisted extractions (EAE) are assessed and applied for APS extraction [9][10][11].In general, the chemical structure of polysaccharides determines its physical, chemical and biochemical properties as well as its biological activities [12]. Several studies have reported that their biological activity is strongly associated with their chemical structure [9]. Due to very complex mechanisms that are affected by many factors, the correlation between polysaccharide structure and biological activity is still not sufficiently clarified.In order to improve isolation of APS, pre-treatments are usually applied to the algal biomass prior to the extraction process with the two aims: (i) to prevent co-extraction of interfering bioactive compounds with similar solubility; and (ii) to disrupt cell walls and improve mass transfer of APS into extraction solvent. The first type of pre-treatments is therefore used to remove compounds which are highly bound to the APS such as proteins, phenols and lipids, as well as mannitol and chlorophyll [13]. For that purpose, the application of various pr...

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Section: Brown Algae Sulfated Polysaccharides As Drug Delivery Systemmentioning

confidence: 99%

Advanced Technologies for the Extraction of Marine Brown Algal Polysaccharides

et al. 2020

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“…Glycidyl methacrylate (M1), 2-aminoethyl methacrylate (M2), and methacrylic anhydride (M3) were employed to functionalize ALG aiming to obtain ALGMx macromers with noticeable structural and electronic differences that could have an effect on the mechanical properties of H-ALGMx hydrogels thereupon produced. The selected methacrylate groups have been indistinctively used in the synthesis of ALG derivatives for biomedical applications [17,[22][23][24]29,30]. Figure 1 shows the reaction schemes of the synthesized macromers at optimized conditions.…”

Section: Synthesis Of Macromers and 1 H-nmr Characterizationmentioning

confidence: 99%

Photocrosslinked Alginate-Methacrylate Hydrogels with Modulable Mechanical Properties: Effect of the Molecular Conformation and Electron Density of the Methacrylate Reactive Group

et al. 2020

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Hydrogels for load-bearing biomedical applications, such as soft tissue replacement, are required to be tough and biocompatible. In this sense, alginate-methacrylate hydrogels (H-ALGMx) are well known to present modulable levels of elasticity depending on the methacrylation degree; however, little is known about the role of additional structural parameters. In this work, we present an experimental-computational approach aimed to evaluate the effect of the molecular conformation and electron density of distinct methacrylate groups on the mechanical properties of photocrosslinked H-ALGMx hydrogels. Three alginate-methacrylate precursor macromers (ALGMx) were synthesized: alginate-glycidyl methacrylate (ALGM1), alginate-2-aminoethyl methacrylate (ALGM2), and alginate-methacrylic anhydride (ALGM3). The macromers were studied by Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and density functional theory method (DFT) calculations to assess their molecular/electronic configurations. In parallel, they were also employed to produce H-ALGMx hydrogels, which were characterized by compressive tests. The obtained results demonstrated that tougher hydrogels were produced from ALGMx macromers presenting the C=C reactive bond with an outward orientation relative to the polymer chain and showing free rotation, which favored in conjunction the covalent crosslinking. In addition, although playing a secondary role, it was also found that the presence of acid hydrogen atoms in the methacrylate unit enables the formation of supramolecular hydrogen bonds, thereby reinforcing the mechanical properties of the H-ALGMx hydrogels. By contrast, impaired mechanical properties resulted from macromer conditions in which the C=C bond adopted an inward orientation to the polymer chain accompanied by a torsional impediment.

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“…Gelators with known amphiphilicity such as surfactants (conventional as well as ionic liquid based) and hydrophilic polymers self-assemble in water through various noncovalent interactions and forms 3D branched networks to form hydrogels or ionogels (in case of ionic liquids) with different characteristics. [3][4][5][6][7] Gelation in these systems are due to the entanglement of the fibres or ribbons where water molecules get entrapped within the 3D network structure through capillary forces or surface tension. [8] Properties of these hydrogels could also be addressed through adjusting various binding sites of the gelators and/or various interactions viz.…”

Section: Introductionmentioning

confidence: 99%

“…[9] Stimuli responsive hydrogels also known as 'smart gels' have found applications in various fields including tissue engineering, drug delivery, sensing the chemical and biological analysts, detection in cell growth, regenerative medicine, light harvesting systems, in the synthesis of inorganic nano-particles as the template to name a few. [10][11][12][13][14][15] Among these, hydrogels that responds to temperature forms one of the most successful classes of hydrogels because of their technological importance. [16][17][18][19][20] Changing the temperature could alter the gelator-gelator and gelator-solvent interactions, that affects the trapping of the solvent within 3D network structure and undergo the phase transition, e.g gel to sol or sol to gel.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Responsive Low Molecular Weight Ionic Liquid Based Gelator: An Approach to Fabricate an Anti‐Cancer Drug‐Loaded Hybrid Ionogel

et al. 2020

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Conceptualising gelators with stimuli responsiveness is advantageous to design smart materials for emerging technologies. These gelators, if are surface active and made up of active pharmaceutical ingredients, can (i) exhibit an interesting pharmaceutical profile, (ii) be useful in drug formulations and (iii) exert direct effects on cell membranes. Herein, cetylpyridinium salicylate (CetPySal) that offers higher surface activity than its precursor surfactant, cetpylpyridinium chloride (CPCl), was synthesised. CetPySal forms a temperature‐responsive ionogel at a critical gelation concentration that changes its physical appearance with temperature, i. e. opaque to transparent, owing to its structural arrangement within its supramolecular framework, that are characterized through spectrometric, calorimetric, scattering and microscopic techniques. The viscoelastic nature of the ionogels was studied through dynamic rheological measurements and the interactions that governs the phase transition were studied through FTIR spectroscopy. The hybrid pharmaceutical ionogels was successfully constructed through encapsulation of the chemotherapeutic drug imatinib mesylate within the ionogel matrix. The sustained release of the drug was investigated from this hybrid ionogel matrix. These results suggest that this new thermo‐responsive ionogel may be used to improve sustained release of drugs and open up new avenues as low‐cost gelators for biomedical applications.

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pH-responsive alginate-based hydrogels for protein delivery

Cited by 80 publications

References 21 publications

Advanced Technologies for the Extraction of Marine Brown Algal Polysaccharides

Advanced Technologies for the Extraction of Marine Brown Algal Polysaccharides

Photocrosslinked Alginate-Methacrylate Hydrogels with Modulable Mechanical Properties: Effect of the Molecular Conformation and Electron Density of the Methacrylate Reactive Group

Temperature‐Responsive Low Molecular Weight Ionic Liquid Based Gelator: An Approach to Fabricate an Anti‐Cancer Drug‐Loaded Hybrid Ionogel

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