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Carboxymethylcellulose (CMC) and keratin nanoparticle (KNP) hydrogels were obtained, characterized, and applied as drug delivery systems (DDSs) for the first time. Lyophilized CMC/KNP mixtures containing 10, 25, and 50 wt% of KNPs were kept at 170 °C for 90 min to crosslink CMC chains through a solid-state reaction with the KNPs. The hydrogels were characterized by infrared spectroscopy, thermal analyses, X-ray diffraction, mechanical measurements, and scanning electron microscopy. The infrared spectra indicated the formation of ester and amide linkages between crosslinked CMC and KNPs. The elastic modulus of the hydrogel containing 10 wt% KNPs was 2-fold higher than that of the hydrogel containing 50 wt% KNPs. The mechanical properties influenced the hydrogel stability and water uptake. The anti-inflammatory prednisolone (PRED) drug was incorporated into the hydrogels, and the release mechanism was investigated. The hydrogels supported PRED release by drug desorption for approximately 360 h. A sustained release mechanism was achieved. The CMC/KNP and CMC/KNP/PRED hydrogels were cytocompatible toward mammalian cells. The CMC/KNP/PRED set imparted the highest cell viability after 7 days of incubation. This study showed a straightforward procedure to create DDSs (chemically crosslinked) based on polysaccharides and proteins for efficient PRED delivery., Competing Interests: Declaration of competing interest The authors have no competing financial interests to declare or personal relationships that can influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Here, we have demonstrated the production and characterization of hydrogel scaffolds based on chitosan/gellan gum (CS/GG) assemblies, without any covalent and metallic crosslinking agents, conventionally used to yield non-soluble polysaccharide-based materials. The polyelectrolyte complexes (physical hydrogels called as PECs) are characterized by Fourier-transform infrared spectroscopy, wide-angle X-ray scattering, and scanning electron microscopy. Hydrogels containing chitosan (CS) excesses (ranging from 60 to 80 wt%) were created. Durable polysaccharide-based scaffolds with structural homogeneity and interconnecting pore networks are developed by modulating the CS/GG weight ratio. The CS/GG hydrogel prepared at 80/20 CS/GG weight ratio (sample CS/GG80-20) is cytocompatible, supporting the attachment, growth, and spreading of bone marrow mesenchymal stem cells (BMSCs) after nine days of cell culture. The cytocompatibility is correlated to the swelling capacity of the PEC in PBS buffer (pH 7.4). By controlling the CS content, we can tune the water uptake of the material, enhancing the capacity to serve as a three-dimensional cell scaffold for BMSCs. This work presents for the first time that CS/GG hydrogels can be applied as scaffolds for tissue engineering purposes., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Proteoglycans have vital biochemical and biomechanical functions. Their proteolytic degradation results in loss of these functions. We have previously reported nonprotein proteoglycan-mimetic graft copolymers that stabilize and deliver growth factors and are not subject to proteases. Here we expand our investigation of these proteoglycan mimics by also investigating their effects on hydrogel mechanical properties. Four polysaccharide side chains, chondroitin sulfate, heparin, dextran, and dextran sulfate, are each grafted to a hyaluronan backbone. The polysaccharides and graft copolymers are added to agarose hydrogels. Cyclic compression and stress relaxation tests reveal how the addition of the polysaccharides and graft copolymers influence hydrogel modulus. Cells encapsulated in agarose hydrogels containing chondroitin sulfate and the chondroitin sulfate graft copolymer have decreased cell viability and metabolic activity compared to cells in unmodified agarose hydrogels. These multifunctional additives can be used to improve both the biochemistry and biomechanics of materials, warranting further optimization to overcome the potentially negative effects these may have on cell viability and activity.

The preparation and characterization of natural polymer-based hydrogels that contain 50-nm diameter magnetite (i.e., FeO:Fe(2)O(3)) nanoparticles are described herein. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the efficiency of the polysaccharide-modifying process. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and compressive moduli demostrate that the presence of magnetite improves thermal and mechanical resistance. Transient diffusion of water in magnetic hydrogels was analyzed via boundary layer mass transfer across an expaning interface, and the degree of swelling of these polysaccharide hydrogels decreases in the presence of magnetite, with no variation in the binary diffusion mechanism. The absence of hysteresis loops and coercivity observed via magnetometry suggests that magnetic hydrogels are useful for remote-controlled drug release, as demonstrated by magnetic-field-induced release of curcumin. Experiments reveal that magnetic hydrogels with greater magnetic susceptibility have the potential to release larger concentrations of drugs from the hydrogel network., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Abstract Here we report a new and straightforward method to yield durable polyelectrolyte complexes (hydrogel PECs) from gellan gum (GG) and chitosan (CS) assemblies, without metallic and covalent crosslinking agents, commonly used to produce GG and CS-based hydrogels, respectively. This new approach overcomes challenges of obtaining stable and durable GG-based hydrogels with structural homogeneity, avoiding precipitation and aqueous instability, typical of PEC-based materials. PECs are created by blending CS:GG solutions (at 60 °C) with GG:CS weight ratios between 80:20 to 40:60. X-ray photoelectron spectroscopy (XPS) analysis shows that CS-GG chains are interacting by electrostatic and intermolecular forces, conferring a high degree of association to the washed PECs, characteristic of self-assembling of polymer chains. The CS:GG weight ratio can be tuned to improve polyelectrolyte complex (PEC) high porosity, stability, porous homogeneity, and degradation rate. Physical and thermosensitive CS/GG-based hydrogels can have advantages over conventional materials produced by chemical processes. Highlights • Chitosan/gellan gum polyelectrolyte complexes were prepared. • Chitosan:gellan gum weight ratio plays a significant role in the features of the materials. • The materials present stability, self-assembling, structural homogeneity and slow degradation rate. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Processing water-soluble polysaccharides, like pectin (PT), into materials with desirable stability and mechanical properties has been challenging. Here we report a new method to create water stable and mechanical resistant polyelectrolyte complex (PEC) membranes from PT and chitosan (CS) assemblies, without covalent crosslinking. This new method overcomes challenges of obtaining stable and durable complexes, by performing the complexation at low pH, enabling complex formation even when using an excess of PT, and when using PT with high degree of O- methoxylation. By performing the complexation at low pH, the complexes form with a high degree of intermolecular association, instead of forming by electrostatic complexation. This method avoids precipitation, and overcomes the aqueous instability typical of PT/CS complexes. After neutralization, the PEC membranes display features characteristic of a high degree of intermolecular association because of the self-assembling of polymer chains. The PT/CS ratio can be tuned to enhance the mechanical strength (σ = 39 MPa) of the membranes. These polysaccharide-based materials can demonstrate advantages over synthetic materials for technological applications. [ABSTRACT FROM AUTHOR]

Chitosan/alginate (CHT/ALG) and magnetic CHT/ALG/Fe 3 O 4 @SiO 2 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 Fe 3 O 4 @SiO 2 (8 ± 3 nm) significantly modified the surface morphology of the composites. The CHT/ALG/Fe 3 O 4 @SiO 2 (8) hydrogel comprising the highest Fe 3 O 4 @SiO 2 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/Fe 3 O 4 @SiO 2 (8) had maximum adsorption capacity (q m ) of 234.77 mg g −1 and adsorption/desorption cycles designed its reuse performance. The CHT/ALG/Fe 3 O 4 @SiO 2 (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/Fe 3 O 4 @SiO 2 as the adsorbent. [ABSTRACT FROM AUTHOR]

This study reports the synthesis, characterization and biological properties of films based on poly(vinyl alcohol) (PVA) and a cationic tannin polymer derivative (TN). Films are obtained from polymeric blends by tuning the PVA/TN weight ratios. The materials are characterized through infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, mechanical analyses, and scanning electron microscopy. More hydrophilic surfaces are created by modulating the PVA and TN concentrations in the blends. Disintegration tests showed that the films present durability in phosphate buffer (pH 7.4) and low stability in simulated gastric fluid (pH 1.2). The film created at 90/10 PVA/TN weight ratio and crosslinked at 109 PVA/glutaraldehyde molar ratio (sample PVA10/TN10) supports the attachment and proliferation of bone marrow mesenchymal stem cells after 7 days of culture. The scaffolding capacity of the PVA10/TN10 surface is compared with titanium, one of the most important biomedical materials used in bone replacements. Also, the PVA/TN films exhibited cytocompatibility, antioxidant and antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. These properties make PVA/TN films are candidates for biomedical applications in the tissue engineering field. Image 1 • New poly(vinyl alcohol)/cationic tannin films are produced. • The more hydrophilic film surface has antimicrobial and antioxidant activities. • The hydrophilic film supports the attachment and proliferation of cells. [ABSTRACT FROM AUTHOR]