Zein is a biodegradable and biocompatible material extracted from renewable resources; it comprises almost 80% of the whole protein content in corn. This review highlights and describes some zein and ...zein-based materials, focusing on biomedical applications. It was demonstrated in this review that the biodegradation and biocompatibility of zein are key parameters for its uses in the food-packing, biomedical and pharmaceutical fields. Furthermore, it was pointed out that the presence of hydrophilic-hydrophobic groups in zein chains is a very important aspect for obtaining material with different hydrophobicities by mixing with other moieties (polymeric or not), but also for obtaining derivatives with different properties. The physical and chemical characteristics and special structure (at the molecular, nano and micro scales) make zein molecules inherently superior to many other polymers from natural sources and synthetic ones. The film-forming property of zein and zein-based materials is important for several applications. The good electrospinnability of zein is important for producing zein and zein-based nanofibers for applications in tissue engineering and drug delivery. The use of zein's hydrolysate peptides for reducing blood pressure is another important issue related to the application of derivatives of zein in the biomedical field. It is pointed out that the biodegradability and biocompatibility of zein and other inherent properties associated with zein's structure allow a myriad of applications of such materials with great potential in the near future.
Chitosan, which is derived from a deacetylation reaction of chitin, has attractive antimicrobial activity. However, chitosan applications as a biocide are only effective in acidic medium due to its ...low solubility in neutral and basic conditions. Also, the positive charges carried by the protonated amine groups of chitosan (in acidic conditions) that are the driving force for its solubilization are also associated with its antimicrobial activity. Therefore, chemical modifications of chitosan are required to enhance its solubility and broaden the spectrum of its applications, including as biocide. Quaternization on the nitrogen atom of chitosan is the most used route to render water-soluble chitosan-derivatives, especially at physiological pH conditions. Recent reports in the literature demonstrate that such chitosan-derivatives present excellent antimicrobial activity due to permanent positive charge on nitrogen atoms side-bonded to the polymer backbone. This review presents some relevant work regarding the use of quaternized chitosan-derivatives obtained by different synthetic paths in applications as antimicrobial agents.
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•Superabsorbent hydrogels (SH) are very important issue in both academic and industrial fields.•Synthesis, characterization and application of SH in agriculture are highlighted in ...this review.•SH based on polysaccharide can be applied as soil conditioners and nutrient carriers.•Mechanisms of water uptake and water transport are discussed based on mathematical models.•Solute release from granules or SH are considered targeting nutrient release for agriculture.
Superabsorbent hydrogels (SH) continue being a very important issue in both academic and industrial fields due to their applications in several technologies. This is proved by the impressive number of publications, through papers and patents as well, dealing with SH. This review is targeted to update and discuss some important aspects of synthesis, characterization and application of SH in agriculture, mainly those based on polysaccharides, as soil conditioners and as polymer carriers for nutrient release. Basic properties of SH and some methods for chemically modifying polysaccharides are given and some directions for hydrogels preparation are highlighted as well. Mechanisms associated with water transport into the 3D matrix, taking into account the transference of mass from hydrogel–soil system to plant, are discussed in the light of some mathematical models. Release of nutrients either from granules coated by hydrophilic polymer or from SH, targeting applications in agriculture, is also discussed on the basis of often used mathematical models (the swelling-based kinetic models) and on a diffusion-based kinetic model with a partition activity coefficient. Examples of recent applications in agriculture as soil conditioners and carriers for nutrient release (fertilizers, etc.) are given. At the final, future trends and perspectives are considered. More than two hundreds references are cited in the whole text.
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Heparin and different chitosan derivatives were applied to produce stable electrostatic layer-by-layer assemblies and further used as coating technique to inhibit natural inflammatory ...response to implants. Heparin was assembled with chitosan and N-methylated chitosan derivatives, namely N,N-dimethyl chitosan (DMC) and N,N,N-trimethyl chitosan (TMC), by dipping method. DMC and TMC (chitosan derivatives) were synthesized and characterized before LbL assembly. Ellipsometry, quartz crystal microbalance (QCM-D), and contact angle were used to demonstrate the deposition of polyelectrolyte multilayers onto silicon wafers using polyelectrolyte solutions with different ionic strength. The biological properties of these films were evaluated by cell culture assays using NIH/3T3 fibroblast cells. LbL assemblies of Heparin and chitosan derivatives showed to be biocompatible, and at the same time they strongly hinder the proliferation speed of fibroblasts up to 40-fold factors. Therefore, the multilayers prepared from heparin and chitosan derivatives have good features to be used as an alternative coating treatment for biomedical implants with reduced body rejection properties.
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•New pectin/chitosan membranes had high tensile strength similar to the skin tissue.•Surface wettability played an important role to promote the attachment of cells.•Membranes may ...provide anchorage, adhesion and support human stem cell growth.
Processing stable polysaccharide membranes with suitable mechanical properties has been challenging for applications in wound healing and tissue engineering. Here we expand the characterization of pectin/chitosan (PT/CS) membranes (without covalent crosslinking), which we recently reported. Membranes containing pectin (PT) excess were formed, and PT/CS ratio can be tuned to enhance the mechanical strength, and to modulate hydrophilicity and cytocompatibility. The surface wettability and swelling properties of the polyelectrolyte complexes (PECs) played an important role to promote the attachment of stem cells. These PECs membranes have ultimate tensile strength similar to that of human skin, which is on the order of ten times higher than similar previously reported polysaccharide materials. We show for the first time that these new PT/CS membranes may promote anchorage, adhesion and support human stem cell growth, making them candidate materials for tissue engineering purposes.
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In this study, a surface modification strategy using natural biopolymers on titanium is proposed to improve bone healing and promote rapid and successful osseointegration of ...orthopedic implants. Titania nanotubes were fabricated via an anodization process and the surfaces were further modified with polyelectrolyte multilayers (PEMs) based on Tanfloc (a cationic tannin derivative) and glycosaminoglycans (heparin and hyaluronic acid). Scanning electron microscopy (SEM), water contact angle measurements, and X-ray photoelectron spectroscopy were used to characterize the surfaces. Adipose-derived stem cells (ADSCs) were seeded on the surfaces, and the cell viability, adhesion, and proliferation were investigated. Osteogenesis was induced and osteogenic differentiation of human ADSCs on the surfaces was evaluated via mineralization and protein expression assays, immunofluorescent staining, and SEM. The Tanfloc/heparin PEMs on titania nanotubes improved the rate of osteogenic differentiation of ADSCs as well as the bone mineral deposition, and is therefore a promising approach for use in orthopedic implants.
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•Polyelectrolyte multilayers based on chitosan/iota-carrageenan and chitosan/pectin are produced.•The polyelectrolyte multilayers have antimicrobial and antiadhesive activities.•The ...polyelectrolyte multilayers support the attachment and proliferation of bone cells.•The polyelectrolyte multilayers promote cytocompatibility of surfaces.
It has been a challenge to develop durable and cytocompatible antibacterial coatings with antiadhesive and antimicrobial activities. To overcome the problems caused by bacteria contamination on biomedical devices, we are proposing layer-by-layer films based on iota-carrageenan/chitosan, and pectin/chitosan polyelectrolyte multilayers (PEMs) assembled in an acetic acid/acetate buffer solution at pH 5.0. PEMs with 5 and 15 layers are established with chitosan-terminated layers. As compared to pectin, the iota-carrageenan promotes a PEM with a more wettable surface (water contact angle of 25°) and a low roughness. The PEMs have strong antiadhesive and bactericidal activities against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). For P. aeruginosa, the effect is seen after 6 h and for S. aureus the effect is seen after 24 h. The antibacterial test in-vitro indicates that PEMs can kill and avoid the attachment of bacteria effectively. To confirm the biomedical potential of these PEMs to act as coatings for tissue scaffolds and implants, adhesion and proliferation of bone marrow-derived stem cells (BMSCs) is demonstrated after 4 and 7 days of incubation. The iota-carrageenan/chitosan PEM supports the BMSCs adhesion, proliferation and spreading, inhibits the attachment and growth of bacteria and promotes cytocompatibility of surfaces.
•New adsorbent materials based on chitosan/alginate and Fe3O4@SiO2 were carried out.•Hydrogel composites acted as adsorbent materials for Pb(II) ions.•Magnetic composites removed Pb(II) ions from ...aqueous systems.•Magnetic composite guaranteed Pb(II) removal of a battery effluent.•Magnetic composite removed the turbidity of a battery effluent.
Chitosan/alginate (CHT/ALG) and magnetic CHT/ALG/Fe3O4@SiO2 composites were successfully prepared and used as adsorbent materials to remove Pb(II) from aqueous systems. New hydrogel beads were yielded through an unpublished methodology, examining the ionic strength of the chitosan (CHT) solutions. Polyvalent cations and toxic cross-linking agents such as glutaraldehyde and epichlorohydrin, frequently used to prepare CHT/ALG-based materials were not used in this study. The samples were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, thermal analysis (TAG/DSC), and zeta potential measurements. The addition of Fe3O4@SiO2 (8 ± 3 nm) significantly modified the surface morphology of the composites. The CHT/ALG/Fe3O4@SiO2(8) hydrogel comprising the highest Fe3O4@SiO2 content (8.0 wt%), displayed magnetic feature and zeta potential of −76.8 mV at pH 6.0. Kinetic and equilibrium adsorption studies reveal that Elovich and Redlich-Peterson mathematical models provide the best fits for the experimental data, respectively. The magnetic composite CHT/ALG/Fe3O4@SiO2(8) had maximum adsorption capacity (qm) of 234.77 mg g−1 and adsorption/desorption cycles designed its reuse performance. The CHT/ALG/Fe3O4@SiO2(8) hydrogel was applied to treat battery effluent, achieving 99.04% Pb(II) removal, and diminishing the turbidity from 73 to 3.0 NTU. Wastewater and battery effluents contaminated with Pb(II) may be treated using an eco-friendly magnetic hybrid material based on CHT/ALG/Fe3O4@SiO2 as the adsorbent.
Modifying materials with biocompatible surface coatings is an important method for controlling cell responses to biomaterials. In this work, tanfloc (TN), a cationic tannin-derivative polymer was ...assembled with heparin (HEP) and chondroitin sulfate (CS), using the layer-by-layer (LbL) approach, to build polyelectrolyte multilayers (PEMs) and to design cytocompatible coatings. LbL deposition was monitored through Fourier-transform surface plasmon resonance, and characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The response of human adipose-derived stem cells (ADSCs) was evaluated
in vitro
. All of the TN-containing PEMs exhibit cytocompatibility and support adhesion, proliferation, and the spreading of ADSCs after 7 days of culture. HEP-TN PEM assembly with 11 layers (HEP-TN
11
) supports the greatest rate of cell proliferation. When TN is the terminal layer of the PEM, the surfaces promote the spreading of ADSCs, indicating that the surface charge and PEM terminal layer are key determinants of the microenvironmental niche that control cellular response. The promotion of stem cell attachment and proliferation makes these surface coatings potentially useful for biomedical implants and regenerative medicine.
Condensed tannin is a biologically derived polycation that can be combined with glycosaminoglycans (chondroitin sulfate and heparin) to prepare polyelectrolyte multilayers that promote stem cell adhesion and proliferation.
Pectin and chitosan films containing glycerol (Gly) at 5, 10, 15, 20, 30, and 40 wt % were prepared in an aqueous HCl solution (0.10 M) by the solvent evaporation method. The unwashed film (UF) ...containing 40 wt % Gly (UF40) had elongation at break (
, %) of 19%. Washed films (WFs) had high tensile strength (
> 46 MPa) and low elongation at break (
, <5.0%), enabling their use in food packaging applications. The polymers' self-assembling occurred during the washing, increasing the stiffness. The XPS analysis suggests that some HCl is lost during the drying process, resulting in a low acid content on the UF surfaces. The UF40 (at 5.0 mg/mL) exhibits cytocompatibility toward mammalian cells and antimicrobial and anti-adhesive properties against
. The remaining HCl in the UF40 can be a disadvantage for food packaging applications; the UF40 (∅ = 8.5 mm; 55 μm thickness) releases H
O
/HCl, reducing the pH to approximately 3.0 when kept in 200 mL distilled water for approximately 30 min. Therefore, we propose the use of UF40 to coat commercial food packaging. The UF40 has low permeability to water vapor and oxygen and works as a barrier against ultraviolet light. The UF40 is also colorless and completely transparent. The UF40 maintained tomatoes' structural integrity for 18 days at room temperature with no oxidation or microorganism contamination. This paper presents a critical viewpoint concerning chitosan-based films with antimicrobial activities.
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