Self-crosslinked chitosan/dialdehyde xanthan gum blended hypromellose hydrogel for the controlled delivery of ampicillin, minocycline and rifampicin

A review of bio-based dialdehyde polysaccharides as multifunctional building blocks for biomedical and food science applications

Food science and biomedical engineering are key disciplines related to human health, with the development of functional materials being an important research direction in both fields. In recent years, dialdehyde polysaccharides (DAPs), as green biopolymers, have become increasingly important in functional materials within food science and biomedical engineering. This work systematically summarizes the sources and properties of various DAPs, introduces their preparation methods and common DAP-based functional biomaterials, including hydrogels, scaffolds, films, coatings, nanoparticles, and nanofibers. Importantly, this work also reviews DAP applications in functional materials for food science and biomedical engineering, such as drug delivery, wound dressings, tissue engineering, food packaging films/edible coatings, food emulsions, antibacterial nanoparticles, and enzyme immobilization. Finally, the work briefly discusses the biosafety of DAPs. To conclude, this study provides a toolkit for developing functional materials in these fields and offers important reference value regarding the broad application of DAPs.

Advances in Bacterial Cellulose-Based Scaffolds for Tissue Engineering: Review

Bacterial cellulose (BC) has emerged as a highly versatile and promising biomaterial in tissue engineering, with potential applications across skin, bone, cartilage, and vascular regeneration. Its exceptional properties like high mechanical strength, superior biocompatibility, excellent moisture retention, and inherent ability to support cell adhesion and proliferation, make BC particularly effective for wound healing and skin regeneration. These attributes accelerate tissue repair and foster new tissue formation, highlighting its value in skin-related applications. Additionally, BC's capacity to support osteogenic differentiation, combined with its mechanical robustness, positions it as a strong candidate for bone tissue engineering, facilitating regeneration and repair. Recent advancements have emphasized the development of BC-based hybrid scaffolds to enhance tissue-specific functionalities, including vascularization and cartilage regeneration. These innovations aim to address the complex requirements of various tissue engineering applications. However, challenges remain, particularly regarding the scalability of BC production, cost-effectiveness, and the long-term stability of BC-based scaffolds. Such barriers continue to limit its broader clinical adoption. This review critically examines the synthesis methods, intrinsic properties, and recent innovations in the design of BC-based scaffolds, offering insights into their potential to revolutionize regenerative medicine. Furthermore, it addresses the key challenges and limitations that must be overcome to enable the clinical integration of BC. By addressing these limitations, BC could play a transformative role in advancing tissue engineering and regenerative therapies, bridging the gap between laboratory research and clinical application.

From nature to nanotech: Harnessing the power of electrospun polysaccharide-based nanofibers as sustainable packaging

Today, the applications of natural polysaccharide-based nanofibers are growing in drug delivery and food industries. They also showed their capability as packaging due to biodegradability, mechanical strength, barrier properties, thermal stability, antioxidant, and antimicrobial features. Natural polysaccharides come from different sources, such as plants, microbes, and animals. Natural polysaccharide-based nanofibers can be considered sustainable packaging in contrast to plastic packaging due to their safety and biodegradability. Smart packaging is a new trend in packaging materials, and natural polysaccharides can be applied as smart packaging. They can work as an indicator that confirms food health in food packaging. Electrospinning is one of the most used methods for the fabrication of nanofibers, and it can also be used for the fabrication of natural polysaccharide nanofibers. This method can be scaled up and used to fabricate nanofibers on a large scale. This paper will review recent studies on natural polysaccharide-based nanofiber as packaging materials and their benefits. We also discuss the challenges and limitations of their scale-up and electrospinning process. Furthermore, we will discuss the future perspective of natural polysaccharide-based nanofiber as a new sustainable packaging.

Electrospun-modified xanthan gum nanofibers enhanced with nisin for food packaging applications

This study investigates developing and characterizing electrospun nanofibers composed of polyvinyl alcohol (PVA) and oxidized xanthan gum (OXG), with nisin as a bioactive agent, for innovative food packaging applications. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed successful crosslinking between PVA and OXG, along with uniform nisin dispersion within the fibers. The inclusion of OXG increased moisture content (MC) and water solubility (WS) while reducing porosity and water vapor permeability (WVP), demonstrating its role as a crosslinker. Conversely, nisin reduced MC to 25.13 ± 0.93 %, WS to 43.45 ± 4.32 %, and increased porosity to 61.5 ± 4.25 % and WVP to 1.75 ± 0.08 × 103 g/h·m2·Pa. Tensile strength significantly improved with higher nisin concentrations, rising from 10.8 ± 2.35 MPa to 20.31 ± 2.94 MPa, attributed to Schiff base crosslinking. Additionally, nisin-containing nanofibers exhibited enhanced antioxidant properties, increasing radical scavenging activity by 65 %. These findings highlight the potential of PVA/OXG/nisin-based nanofibers to address gaps in food packaging by offering robust mechanical strength, superior barrier properties, and bioactive functionality, paving the way for next-generation packaging solutions that extend shelf life and reduce environmental impact.

An innovative rheology analysis method applies to the formulation optimization of Panax notoginseng total saponins ocular gel

Emphasizing the viscoelasticity of ophthalmic gels is crucial for understanding the residence time, structure, and stability of hydrogels. This study primarily aimed to propose an innovative rheology analysis method for ophthalmic gels, considering complex eye movements. This method was applied to select ophthalmic gels with favorable rheological characteristics. Additionally, the physical characteristics and in vitro release of the selected Panax notoginseng total saponins (PNS) gel were demonstrated. The selected PNS gel significantly increased the activities of SOD and decreased intracellular levels of MDA, TNF-α, and IL-1β in H2O2-treated ARPE-19 cells. Finally, the optimal formulation was selected as a suitable platform for ophthalmic delivery and was shown to significantly rescue ARPE-19 cells from oxidative cellular damage.

Food packaging films from natural polysaccharides and protein hydrogels: A comprehensive review

The development of innovative, biodegradable food packaging materials to combat plastic pollution has garnered significant attention from scholars and government agencies worldwide. Natural polysaccharides and proteins exhibit excellent modifiability, biodegradability, high ductility, and compatibility with food products, making them ideal candidates for constructing hydrogels. Hydrogel films based on these biopolymers have opened new research horizons in food packaging applications. This review examines natural polysaccharides and proteins commonly used in hydrogel film preparation and explores strategies to improve their packaging performance, including the use of binary mixtures and exogenous additives. To optimize functionality, the cross-linking mechanisms between materials and film-forming methods are summarized. Additionally, recent applications of hydrogel films in food packaging in are discussed, showcasing their ability to extend or monitor food freshness. Despite existing challenges, the current advancements present a promising and sustainable alternative to conventional plastic materials paving the way for innovative packaging solutions.

Applied research and recent advances in the development of flexible sensing hydrogels from cellulose: A review

Flexible wearable smart sensing materials have gained immense momentum, and biomass-based hydrogel sensors for renewable and biologically safe wearable sensors have attracted significant attention in order to meet the growing demand for sustainability and ecological friendliness. Cellulose has been widely used in the field of biomass-based hydrogel sensing materials, being the most abundant biomass material in nature. This review mainly focuses on the types of cellulose hydrogels, the preparation methods and their applications in smart flexible sensing materials. The structure-functional properties-application relationship of cellulose hydrogels and the applications of various cellulose hydrogels in flexible sensing are described in detail. Then it focuses on the methods and mechanisms of cellulose hydrogel flexible sensors preparation, and then summarizes the research of cellulose hydrogel sensors for different types of stimulus response mechanisms to pressure, pH, biomolecules, ions, temperature, humidity, and light. The applications of cellulose hydrogels as flexible sensing materials in biomedical sensing, smart wearable and environmental monitoring are further summarized. Finally, the future development trend of cellulose hydrogels is briefly introduced and the future development of cellulose hydrogel sensing materials is envisioned.

Oxidized ionic polysaccharide hydrogels: Review on derived scaffolds characteristics and tissue engineering applications

Polysaccharide-based hydrogels have gained prominence due to their non-toxicity, biocompatibility, and structural adaptability for constructing tissue engineering scaffolds. Polysaccharide crosslinking is necessary for hydrogel stability in vivo. The periodate oxidation enables the modification of native polysaccharide characteristics for wound healing and tissue engineering applications. It produces dialdehydes, which are used to crosslink biocompatible amine-containing macromolecules such as chitosan, gelatin, adipic acid dihydrazide, silk fibroin, and peptides via imine/hydrazone linkages. Crosslinked oxidized ionic polysaccharide hydrogels have been studied for wound healing, cardiac and liver tissue engineering, bone, cartilage, corneal tissue regeneration, abdominal wall repair, nucleus pulposus regeneration, and osteoarthritis. Several modified hydrogel systems have been synthesized using antibiotics and inorganic substances to improve porosity, mechanical and viscoelastic properties, desired swelling propensity, and antibacterial efficacy. Thus, the injectable hydrogels provide a host-tissue-mimetic environment with high cell adhesion and viability, making them appropriate for scarless wound healing and tissue engineering applications. This review describes the oxidation procedure for alginate, hyaluronic acid, gellan gum, pectin, xanthan gum and chitosan, as well as the characteristics of the resulting materials. Furthermore, a critical review of scientific advances in wound healing and tissue engineering applications has been provided.

A self-healing crosslinked-xanthan gum/soy protein based film containing halloysite nanotube and propolis with antibacterial and antioxidant activity for wound healing

Traumatic multidrug-resistant bacterial infections are the most threat to wound healing. Lower extremity wounds under diabetic conditions display a significant delay during the healing process. To overcome these challenges, the utilization of protein-based nanocomposite dressings is crucial in implementing a successful regenerative medicine approach. These dressings hold significant potential as polymer scaffolds, allowing them to mimic the properties of the extracellular matrix (ECM). So, the objective of this study was to develop a nanocomposite film using dialdehyde-xanthan gum/soy protein isolate incorporated with propolis (PP) and halloysite nanotubes (HNTs) (DXG-SPI/PP/HNTs). In this protein-polysaccharide hybrid system, the self-healing capability was demonstrated through Schiff bonds, providing a favorable environment for cell encapsulation in the field of tissue engineering. To improve the properties of the DXG-SPI film, the incorporation of polyphenols found in PP, particularly flavonoids, is proposed. The synthesized films were subjected to investigations regarding degradation, degree of swelling, and mechanical characteristics. Additionally, halloysite nanotubes (HNTs) were introduced into the DXG-SPI/PP nanocomposite films as a reinforcing filler with varying concentrations of 3 %, 5 %, and 7 % by weight. The scanning electron microscope (SEM) analysis confirmed the proper embedding and dispersion of HNTs onto the DXG-SPI/PP nanocomposite films, leading to functional interfacial interactions. The structure and crystallinity of the synthesized nanocomposite films were characterized using Fourier Transform Infrared Spectrometry (FTIR) and X-ray diffraction (XRD), respectively. Moreover, the developed DXG-SPI/PP/HNTs nanocomposite films significantly improved cell growth of NIH-3T3 fibroblast cells in the presence of PP and HNTs, indicating their cytocompatibility. The antibacterial activity of the nanocomposite was evaluated against Escherichia coli (E. Coli) and Staphylococcus aureus (S. Aureus), which are commonly associated with wound infections. Overall, our findings suggest that the synthesis of DXG-SPI/PP/HNTs nanocomposite scaffolds holds great promise as a clinically relevant biomaterial and exhibits strong potential for numerous challenging biomedical applications.

Chitosan-Oxidized Pullulan Hydrogels Loaded with Essential Clove Oil: Synthesis, Characterization, Antioxidant and Antimicrobial Properties

Emulsion hydrogels are promising materials for encapsulating and stabilizing high amounts of hydrophobic essential oils in hydrophilic matrices. In this work, clove oil-loaded hydrogels (CS/OP-C) are synthesized by combining covalent and physical cross-linking approaches. First, clove oil (CO) was emulsified and stabilized in a chitosan (CS) solution, which was further hardened by Schiff base covalent cross-linking with oxidized pullulan (OP). Second, the hydrogels were subjected to freeze-thaw cycles and, as a result, the clove oil was stabilized in physically cross-linked polymeric walls. Moreover, due to cryogelation, the obtained hydrogels exhibited sponge-like porous interconnected morphology (160-250 µm). By varying the clove oil content in the starting emulsion and the degree of cross-linking, the hydrogels displayed a high water retention capacity (swelling ratios between 1300 and 2000%), excellent elastic properties with fast shape recovery (20 s) after 70% compression, and controlled in vitro clove oil release in simulated skin conditions for 360 h. Furthermore, the prepared clove oil-loaded hydrogels had a strong scavenging activity of 83% and antibacterial and antifungal properties, showing a bacteriostatic effect after 48 and 72 h against S. aureus and E. coli. Our results recommend the new clove oil-embedded emulsion hydrogels as promising future materials for application as wound dressings.

Natural gums and their derivatives based hydrogels: in biomedical, environment, agriculture, and food industry

The hydrogels based on natural gums and chemically derivatized natural gums have great interest in pharmaceutical, food, cosmetics, and environmental remediation, due to their: economic viability, sustainability, nontoxicity, biodegradability, and biocompatibility. Since these natural gems are from plants, microorganisms, and seaweeds, they offer a great opportunity to chemically derivatize and modify into novel, innovative biomaterials as scaffolds for tissue engineering and drug delivery. Derivatization improves swelling properties, thereby developing interest in agriculture and separating technologies. This review highlights the work done over the past three and a half decades and the possibility of developing novel materials and technologies in a cost-effective and sustainable manner. This review has compiled various natural gums, their source, chemical composition, and chemically derivatized gums, various methods to synthesize hydrogel, and their applications in biomedical, food and agriculture, textile, cosmetics, water purification, remediation, and separation fields.

Augmented physical, mechanical, and cellular responsiveness of gelatin-aldehyde modified xanthan hydrogel through incorporation of silicon nanoparticles for bone tissue engineering

Bioactive scaffolds fabricated from a combination of organic and inorganic biomaterials are a promising approach for addressing defects in bone tissue engineering. In the present study, a self-crosslinked nanocomposite hydrogel, composed of gelatin/aldehyde-modified xanthan (Gel-AXG) is successfully developed by varying concentrations of porous silicon nanoparticles (PSiNPs). The effect of PSiNPs incorporation on physical, mechanical, and biological performance of the nanocomposite hydrogel is evaluated. Morphological analysis reveals formation of highly porous 3D microstructures with interconnected pores in all nanocomposite hydrogels. Increased content of PSiNPs results in a lower swelling ratio, reduced porosity and pore size, which in turn impeded media penetration and slowed down the degradation process. In addition, remarkable enhancements in dynamic mechanical properties are observed in Gel-AXG-8%Si (compressive strength: 0.6223 MPa at 90 % strain and compressive modulus: 0.054 MPa), along with improved biomineralization ability via hydroxyapatite formation after immersion in simulated body fluid (SBF). This optimized nanocomposite hydrogel provides a sustained release of Si ions at safe dose levels. Furthermore, in-vitro cytocompatibility studies using MG-63 cells exhibited remarkable performance in terms of cell attachment, proliferation, and ALP activity for Gel-AXG-8%Si. These findings suggest that the prepared nanocomposite hydrogel holds promising potential as a scaffold for bone tissue engineering.

Rational design of viscoelastic hydrogels for periodontal ligament remodeling and repair

The periodontal ligament (PDL) is a distinctive yet critical connective tissue vital for maintaining the integrity and functionality of tooth-supporting structures. However, PDL repair poses significant challenges due to the complexity of its mechanical microenvironment encompassing hard-soft-hard tissues, with the viscoelastic properties of the PDL being of particular interest. This review delves into the significant role of viscoelastic hydrogels in PDL regeneration, underscoring their utility in simulating biomimetic three-dimensional microenvironments. We review the intricate relationship between PDL and viscoelastic mechanical properties, emphasizing the role of tissue viscoelasticity in maintaining mechanical functionality. Moreover, we summarize the techniques for characterizing PDL's viscoelastic behavior. From a chemical bonding perspective, we explore various crosslinking methods and characteristics of viscoelastic hydrogels, along with engineering strategies to construct viscoelastic cell microenvironments. We present a detailed analysis of the influence of the viscoelastic microenvironment on cellular mechanobiological behavior and fate. Furthermore, we review the applications of diverse viscoelastic hydrogels in PDL repair and address current challenges in the field of viscoelastic tissue repair. Lastly, we propose future directions for the development of innovative hydrogels that will facilitate not only PDL but also systemic ligament tissue repair. STATEMENT OF SIGNIFICANCE.

Polysaccharides gums in drug delivery systems: A review

For the drug delivery system, drug carriers' selection is critical to the drug's success in reaching the desired target. Drug carriers from natural biopolymers are preferred over synthetic materials due to their biocompatibility. The use of polysaccharide gums in the drug delivery system has received considerable attention in recent years. Polysaccharide gums are renewable resources and abundantly found in nature. They could be isolated from marine algae, microorganisms, and higher plants. In terms of carbohydrates, the gums are water-soluble, non-starch polysaccharides with high commercial value. Polysaccharide gums are widely used for controlled-release products, capsules, medicinal binders, wound healing agents, capsules, and tablet excipients. One of the essential applications of polysaccharide gum is drug delivery systems. The various kinds of polysaccharide gums obtained from different plants, marine algae, and microorganisms for the drug delivery system application are discussed comprehensively in this review paper.

A synergistic strategy of dual-crosslinking and loading intelligent nanogels for enhancing anti-coagulation, pro-endothelialization and anti-calcification properties in bioprosthetic heart valves

Currently, glutaraldehyde (GA)-crosslinked bioprosthetic heart valves (BHVs) still do not guarantee good biocompatibility and long-term effective durability for clinical application due to their subacute thrombus, inflammation, calcification, tearing and limited durability. In this study, double-modified xanthan gum (oxidized/vinylated xanthan gum (O2CXG)) was acquired from xanthan gum for subsequent double crosslinking and modification platform construction. Sulfonic acid groups with anticoagulant properties were also introduced through the free radical polymerization of vinyl sulfonate (VS) and vinyl on O2CXG. Taking advantage of the drug-loading function of xanthan gum, the treated pericardium was further loaded with inflammation-triggered dual drug-loaded nanogel (heparin (Hep) and atorvastatin (Ator)). Mechanical properties of O2CXG-crosslinked porcine pericardium (O2CXG-PP) were significantly improved via the first network formed by Schiff base bonds and the second C-C bonds network. Due to the presence of sulfonic acid groups as well as the dual drug release from nanogels under the stimulation of H2O2, the hemocompatibility, anti-inflammatory, pro-endothelialization and anti-calcification properties of the crosslinked pericardium modified with nanogels loaded with Hep and Ator (O2CXG+VS+(Hep+Ator) nanogel-PP) was significantly better than that of GA-crosslinked PP (GA-PP). The collaborative strategy of double crosslinking and sequential release of anticoagulant/endothelium-promoting drugs triggered by inflammation could effectively meet the requirement of enhanced multiple performance and long-term durability of bioprosthetic heart valves and provide a valuable pattern for multi-functionalization of blood contacting materials. STATEMENT OF SIGNIFICANCE: Currently, glutaraldehyde-crosslinked bioprosthetic heart valves (BHVs) are subject to subacute thrombus, inflammation, calcification and tearing, which would not guarantee good biocompatibility and long-term effective durability. We developed a cooperative strategy of double crosslinking and surface modification in which double-modified xanthan gum plays a cornerstone. The mechanical properties of this BHV were significantly improved via the first network formed by Schiff base bonds and the second C-C bonds network. Inflammation-triggered combination delivery of heparin and atorvastatin has been demonstrated to enhance anticoagulation, anti-inflammatory and pro-endothelialization of BHVs by utilizing local inflammatory response. The collaborative strategy could effectively meet the requirement of enhanced multiple performance and long-term durability of BHVs and provide a valuable pattern for the multi-functionalization of blood-contacting materials.

Weaving the next generation of (bio)materials: Semi-interpenetrated and interpenetrated polymeric networks for biomedical applications

Advances in polymer science have led to the development of semi-interpenetrated and interpenetrated networks (SIPN/IPN). The interpenetration procedure allows enhancing several important properties of a polymeric material, including mechanical properties, swelling capability, stimulus-sensitive response, and biological performance, among others. More interestingly, the interpenetration (or semi-interpenetration) can be achieved independent of the material size, that is at the macroscopic, microscopic, or nanometric scale. SIPN/IPN have been used for a wide range of applications, especially in the biomedical field, including tissue engineering, delivery of chemical compounds or biological macromolecules, and multifunctional systems as theragnostic platforms. In the last years, this fascinating field has gained a great interest in the area of polymers for therapeutics; therefore, a comprehensive revision of the topic is timely. In this review, we describe in detail the most relevant synthetic approaches to fabricate polymeric IPN and SIPN, ranging from nanoscale to macroscale. The advantages of typical synthetic methods are analyzed, as well as novel and promising trends in the field of advanced material fabrication. Furthermore, the characterization techniques employed for these materials are summarized from physicochemical, thermal, mechanical, and biological perspectives. The applications of novel (semi-)interpenetrated structures are discussed with a focus on drug delivery, tissue engineering, and regenerative medicine, as well as combinations thereof.

A study on the effect of bioactive glass and hydroxyapatite-loaded Xanthan dialdehyde-based composite coatings for potential orthopedic applications

The most important challenge faced in designing orthopedic devices is to control the leaching of ions from the substrate material, and to prevent biofilm formation. Accordingly, the surgical grade stainless steel (316L SS) was electrophoretically deposited with functional composition of biopolymers and bioceramics. The composite coating consisted of: Bioglass (BG), hydroxyapatite (HA), and lawsone, that were loaded into a polymeric matrix of Xanthan Dialdehyde/Chondroitin Sulfate (XDA/CS). The parameters and final composition for electrophoretic deposition were optimized through trial-and-error approach. The composite coating exhibited significant adhesion strength of "4B" (ASTM D3359) with the substrate, suitable wettability of contact angle 48°, and an optimum average surface roughness of 0.32 µm. Thus, promoting proliferation and attachment of bone-forming cells, transcription factors, and proteins. Fourier transformed infrared spectroscopic analysis revealed a strong polymeric network formation between XDA and CS. scanning electron microscopy and energy dispersive X-ray spectroscopy analysis displayed a homogenous surface with invariable dispersion of HA and BG particles. The adhesion, hydrant behavior, and topography of said coatings was optimal to design orthopedic implant devices. The said coatings exhibited a clear inhibition zone of 21.65 mm and 21.04 mm with no bacterial growth against Staphylococcus aureus (S. Aureus) and Escherichia coli (E. Coli) respectively, confirming the antibacterial potential. Furthermore, the crystals related to calcium (Ca) and HA were seen after 28 days of submersion in simulated body fluid. The corrosion current density, of the above-mentioned coating was minimal as compared to the bare 316L SS substrate. The results infer that XDA/CS/BG/HA/lawsone based composite coating can be a candidate to design coatings for orthopedic implant devices.

Development of double crosslinked sodium alginate/chitosan based hydrogels for controlled release of metronidazole and its antibacterial activity

Double network sodium alginate/chitosan hydrogels were prepared using calcium chloride (CaCl2) and glutaraldehyde as the crosslinking agents by the ionotropic interaction method for controlled metronidazole release. The effect of polymer ratios and CaCl2 amount is investigated by the developing porosity, gel fraction, and extent of swelling in simulated physiological fluids. Interaction between the polymers with the formation of crosslinked structures, good stability, phase nature, and morphology of the hydrogels is revealed by Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. A sodium alginate/chitosan hydrogel (weight ratio of 75:25) crosslinked with two percent CaCl2 is chosen for the in-situ loading of 200 mg of metronidazole. The drug release kinetics using different models show that the best-fit Korsmeyer-Peppas model suggests metronidazole release from the matrix follows diffusion and swelling-controlled time-dependent non-Fickian transport related to hydrogel erosion. This composition displays enhanced antimicrobial activity against Staphylococcus aureus and Escherichia coli.

Novel electrospun nanofibers based on gelatin/oxidized xanthan gum containing propolis reinforced by Schiff base cross-linking for food packaging

Gelatin-based electrospun fibers are promising materials for food packaging but suffer from high hydrophilicity and weak mechanical properties. To overcome these limitations, in the current study, gelatin-based nanofibers were reinforced by using oxidized xanthan gum (OXG) as a crosslinking agent. The nanofibers' morphology was investigated through SEM, and the observations showed that the fibers' diameter was decreased by enhancing OXG content. The resultant fibers with more OXG content exhibited high tensile stress so the optimal sample obtained showed a tensile stress of 13.24 ± 0.76 MPa, which is up to 10 times more than neat gelatin fiber. Adding OXG to gelatin fibers reduced water vapor permeability, water solubility, and moisture content properties while increasing thermal stability and porosity. Additionally, the nanofibers containing propolis displayed a homogenous morphology with high antioxidant and antibacterial activities. In general, the findings suggested that the designed fibers could be used as a matrix for active food packaging.

Dialdehyde xanthan gum and curcumin synergistically crosslinked bioprosthetic valve leaflets with anti-thrombotic, anti-inflammatory and anti-calcification properties

Currently commercial glutaraldehyde (GA)-crosslinked bioprosthetic valve leaflets (BVLs) suffer from thromboembolic complications, calcification, and limited durability, which are the major stumbling block to wider clinical application of BVLs. Thus, developing new-style BVLs will be an urgent need to enhance the durability of BVLs and alleviate thromboembolic complications. In this study, a quick and effective collaborative strategy of the double crosslinking agents (oxidized polysaccharide and natural active crosslinking agent) was reported to realize enhanced mechanical, and structural stability, excellent hemocompatibility and anti-calcification properties of BVLs. Dialdehyde xanthan gum (AXG) exhibiting excellent stability to heat, acid-base, salt, and enzymatic hydrolysis was first introduced to crosslink decellularized porcine pericardium (D-PP) and then curcumin with good properties of anti-inflammatory, anti-coagulation, anti-liver fibrosis, and anti-atherosclerosis was used to synergistically crosslink and multi-functionalize D-PP to obtain AXG + Cur-PP. A comprehensive evaluation of structural characterization, hemocompatibility, endothelialization potential, mechanical properties and component stability showed that AXG + Cur-PP exhibited better anti-thrombotic properties and endothelialization potential, milder immune responses, excellent anti-calcification properties and enhanced mechanical properties compared with GA-crosslinked PP. Overall, this cooperative crosslinking strategy provides a novel solution to achieve BVLs with enhanced mechanical properties and excellent anti-coagulation, anti-inflammatory, anti-calcification, and the ability to promote endothelial cell proliferation.

In situ forming dialdehyde xanthan gum-gelatin Schiff-base hydrogels as potent controlled release fertilizers

Controlled release fertilizer (CRF) hydrogels have blossomed into promising materials in agriculture owing to the sustained release of the fertilizer and also as soil conditioner. Apart from the traditional CRF hydrogels; Schiff-base hydrogels have garnered significant thrust that release nitrogen slowly in addition to reducing the environmental pollution. Herein, we have fabricated Schiff-base CRF hydrogels composed of dialdehyde xanthan gum (DAXG) and gelatin. The formation of the hydrogels was accomplished via the simplistic in situ crosslinking reaction between the aldehyde groups of DAXG and the amino groups of gelatin. The hydrogels acquired a compact network upon increasing the DAXG content in the matrix. The phytotoxic assay on different plants indicated the hydrogels to be nontoxic. The hydrogels demonstrated good water-retention behaviour in soil, along with reusability even after 5 cycles. A controlled release profile for urea was evident from the hydrogels wherein macromolecular relaxation played a crucial role in the release mechanism. Growth assays on Abelmoschus esculentus (Okra) plant presented an intuitive evaluation on the growth and water-holding capacity of the CRF hydrogel. The present work demonstrated a facile preparation of CRF hydrogels to enhance the utilization of urea and retain soil humidity as fertilizer carriers.

Self-cross-linked starch/chitosan hydrogel as a biocompatible vehicle for controlled release of drug

A facile one-pot approach was adopted to prepare a polysaccharide-based hydrogel of oxidized starch (OS)-chitosan. The synthetic monomer-free, eco-friendly hydrogel was prepared in an aqueous solution and employed for controlled drug release application. The starch was first oxidized under mild conditions to prepare its bialdehydic derivative. Subsequently, the amino group-containing a modified polysaccharide, "chitosan" was introduced on the backbone of OS via a dynamic Schiff-base reaction. The bio-based hydrogel was obtained via a one-pot in-situ reaction, where functionalized starch acts as a macro-cross-linker that contributes structural stability and integrity to the hydrogel. The introduction of chitosan contributes stimuli-responsive properties and thus pH-sensitive swelling behavior was obtained. The hydrogel showed its potential as a pH-dependent controlled drug release system and a maximum of 29 h sustained release period was observed for ampicillin sodium salt drug. In vitro studies confirmed that the prepared drug-loaded hydrogels showed excellent antibacterial ability. Most importantly, the hydrogel could find potential use in the biomedical field due to its facile reaction conditions, biocompatibility along with the controlled releasing ability of the encapsulated drug.

Montmorillonite-Rifampicin Nanohybrid for pH-Responsive Release of the Tuberculostatic

The present work describes the development of a hybrid and pH-responsive system for rifampicin using the clay mineral 'montmorillonite' as a nanocarrier. The influence of operational variables on the drug incorporation process was evaluated using 2⁴ factorial designs. Under optimized conditions, the experiment allowed an incorporated drug dose equivalent to 98.60 ± 1.21 mg/g. Hybrid systems were characterized by different characterization techniques (FTIR, XRD, TGA, DSC, and SEM) to elucidate the mechanism of interaction between the compounds used. Through in vitro release studies, it was possible to verify the efficacy of the pH-dependent system obtained, with approximately 70% of the drug released after sixteen hours in simulated intestinal fluid. The adjustment of the experimental release data to the theoretical model of Higuchi and Korsmeyer-Peppas indicated that the release of rifampicin occurs in a prolonged form from montmorillonite. Elucidation of the interactions between the drug and this raw clay reinforces its viability as a novel carrier to develop an anti-TB/clay hybrid system with good physical and chemical stability.

Multifunctional hydrogels for wound dressings using xanthan gum and polyacrylamide

Developing advanced dressings that integrate multiple functions is one of the major challenges in current clinical wound treatment. In this study, Xanthan gum (XG) and polyacrylamide (PAAm) materials were used to prepare hydrogel dressings by one-pot method. With the combination of the PAAm network and the XG network, the PAAm-XG hydrogels showed the tensile strength of 0.36 MPa and the stretchability as large as 2078 %. The prepared PAAm-XG hydrogels had excellent water uptake efficiency with the swelling ratio of 1200 %. Besides, the developed dressings possessed outstanding biocompatibility, universal adhesion and self-healing ability. More importantly, the PAAm-XG hydrogels can be successfully loaded with Cefixime and human recombinant epidermal growth factor, and these loaded hydrogels released these bioactive molecules in sustained ways. As a result, both E. coli and S. aureus bacteria were inactivated after contacting with the Cefixime-loaded hydrogels for 24 h. Furthermore, in vivo data demonstrated that the PAAm-XG hydrogel dressings significantly accelerated the wound healing in a mouse model. All of these indicate that the multifunctional PAAm-XG hydrogels are promising candidates for wound treatment.

Controlled and Sequential Delivery of Stromal Derived Factor-1 α (SDF-1α) and Magnesium Ions from Bifunctional Hydrogel for Bone Regeneration

Bone healing is a complex process that requires the participation of cells and bioactive factors. Stromal derived factor-1 α (SDF-1α) and magnesium ions (Mg²⁺) both are significant bioactive factors for cell recruitment and osteogenesis during bone regeneration. Thus, a bifunctional hydrogel containing a sequential delivery system is fabricated to improve osteogenesis. During sequential delivery of the hydrogel, SDF-1α is predominantly released at the early stage of bone mesenchymal stem cells (BMSCs) recruitment, while Mg²⁺ are constantly delivered at a later stage to improve osteogenic differentiation of recruited cells. In addition, due to the early release of SDF-1α, the hydrogel showed strong BMSCs recruitment and proliferation activity. Mg²⁺ can not only induce up-regulation of osteogenic gene expression in vitro, but also promote bone tissue and angiogenesis in vivo. Taken together, the injection of xanthan gum-polydopamine crosslinked hydrogel co-loading SDF-1α and Mg²⁺ (XPMS hydrogel) provides a novel strategy to repair bone defects.

Dialdehyde Starch Nanocrystals as a Novel Cross-Linker for Biomaterials Able to Interact with Human Serum Proteins

In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5-15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.

High-resolution 3D printing of xanthan gum/nanocellulose bio-inks

The current study provides a comprehensive rheology study and a survey on direct ink writing of xanthan gum/cellulose nanocrystal (XG/CNC) bio-inks for developing 3D geometries that mimic soft tissue engineering scaffolds' physical and mechanical properties. The presence of CNC was found to be a critical prerequisite for the printability of XG bio-inks; accordingly, the hybrid XG/CNC bio-inks revealed the excellent viscoelastic properties that enabled precise control of hydrogel shaping and printing of lattice structures composed of up to eleven layers with high fidelity and fair resolution without any deformation after printing. The lyophilized 3D scaffolds presented a porous structure with open and interconnected pores and a porosity higher than 70%, vital features for tissue engineering scaffolds. Moreover, they showed a relatively high swelling of approximately 11 g/g, facilitating oxygen and nutrient exchange. Furthermore, the elastic and compressive moduli of the scaffolds that enhanced significantly upon increasing CNC content were in the range of a few kPa, similar to soft tissues. Finally, no significant cell cytotoxicity was observed against human liver cancer cells (HepG2), highlighting the potential of these developed 3D printed scaffolds for soft tissue engineering applications.

Antimicrobial cellulose hydrogels preparation with RIF loading from bamboo parenchyma cells: A green approach towards wound healing

Wound healing is a challenged and complicated process due to the bacterial infections and frequent replacement in healing process. Hydrogels with properties of visibility and biocompatibility provided convenient and effective treatment during the wound healing process. Bamboo parenchyma cells have a great potential utilized on cellulosic materials fabrication for their high specific surface area and accessibility of chemical reagents. Herein, we present a simple and facile manufacture of transparent wound dressing from bamboo parenchymal cellulose via dissolution in DMAc/LiCl system. Rifampicin (RIF) was loaded on the hydrogel through immersion method. The result exhibited that the maximum drug loading efficiency of cellulose hydrogels was 82.13%. Hydrogel loaded RIF (HLR) showed that the inhibition zones against Gram-negative and Gram-positive bacteria were 19.11 mm and 36.93 mm, respectively. It was observed that the wound was healed more than 60% at 11th day in murine wound models. Meanwhile, RIF provided an exceptionally antibacterial property to hydrogels and promoted proliferation of epidermis cells in wound. As a result of observations, HLR demonstrating potential application in visual wound dressing materials for their excellent transparency, antibacterial effect, wound healing, and biocompatibility.

Evidence from Thermal Aging Indicating That the Synergistic Effect of Glyoxal and Sodium Sulfite Improved the Thermal Stability of Conformational Modified Xanthan Gum

Xanthan gum is prone to thermal oxidative degradation, which limits its applications. However, conformational changes in xanthan gum and appropriate stabilizers may improve its thermal stability. Therefore, in this study, we aimed to establish a strategy to maintain the viscosity of xanthan gum during long-term storage at high temperatures. We modified the original strain used for xanthan gum production by genetic engineering and added stabilizers during the production process. The structure and thermal stability of the resulting xanthan gum samples were then determined. Pyruvyl deficiency, combined with the addition of sodium sulfite and glyoxal during the production process, was found to significantly improve the maintenance of viscosity. The apparent viscosity of the new xanthan gum solution remained above 100 mPa·s after being stored at 90 °C for 48 days. Fourier-transform infrared spectra and scanning electron microscopy images showed that pyruvate-free xanthan gum with added stabilizers had more extensive cross-linking than natural xanthan gum. In conclusion, these findings may contribute to the use of xanthan gum in applications that require high temperatures for a long period of time.

An Overview of Cellulose Derivatives-Based Dressings for Wound-Healing Management

Presently, notwithstanding the progress regarding wound-healing management, the treatment of the majority of skin lesions still represents a serious challenge for biomedical and pharmaceutical industries. Thus, the attention of the researchers has turned to the development of novel materials based on cellulose derivatives. Cellulose derivatives are semi-synthetic biopolymers, which exhibit high solubility in water and represent an advantageous alternative to water-insoluble cellulose. These biopolymers possess excellent properties, such as biocompatibility, biodegradability, sustainability, non-toxicity, non-immunogenicity, thermo-gelling behavior, mechanical strength, abundance, low costs, antibacterial effect, and high hydrophilicity. They have an efficient ability to absorb and retain a large quantity of wound exudates in the interstitial sites of their networks and can maintain optimal local moisture. Cellulose derivatives also represent a proper scaffold to incorporate various bioactive agents with beneficial therapeutic effects on skin tissue restoration. Due to these suitable and versatile characteristics, cellulose derivatives are attractive and captivating materials for wound-healing applications. This review presents an extensive overview of recent research regarding promising cellulose derivatives-based materials for the development of multiple biomedical and pharmaceutical applications, such as wound dressings, drug delivery devices, and tissue engineering.

Fabrication and characterization of novel antibacterial chitosan/dialdehyde guar gum hydrogels containing pomegranate peel extract for active food packaging application

This study aimed to investigate synthesis and structural characteristics of the chitosan (CS) - modified dialdehyde guar gum (DAGG) hydrogel through the Schiff base reaction. The highest swelling capacity was achieved as about 12,000% of dry weight of the freeze-dried powder at CS: DAGG hydrogel with the mixing ratio of 30:70. The swelling ratio was not affected by changes in pH, which could be considered as an important property in the control of moisture in absorbent pad. The FTIR results indicated that the new amide groups have been formed at 1680 cm^-1, which can be attributed to the covalent bond between the amide groups of CS and the aldehyde groups of GG. Based on a SEM image, the prepared hydrogel showed the porous structure so it verified the crosslinking formation between the two polymers. Rheological analyses confirmed that formation compact and porous structure led to some noteworthy improvements in the strength of hydrogel prepared with a high ratio of DAGG. The hydrogel loaded with 5% pomegranate peel extract (PPE) showed both good antioxidant (81.13%) and antimicrobial activities. The hydrogel was observed to have a good potential to be used as an antibacterial pad.

Magnetic chitosan nanocomposites for simultaneous hyperthermia and drug delivery applications: A review

Cancer is one of the major causes of death worldwide, and its prevalence is rising every day. New methods and materials with multifunctional tasks such as simultaneous hyperthermia treatment and drug release with minimum side effects are highly demanded. Magnetic chitosan nanocomposites can be utilized for localized tumor heating under magnetic field and have a controlled anticancer drug release due to unique functional groups of chitosan with the least complications. Combining different types of magnetic cores and engineered chitosan shells can create unique characteristics such as biocompatibility, the least toxic effects, long-term circulation in the body, controlled drug released, and the ability to carry various medicines. Recent advances in the synthesis, development, and applications of magnetic chitosan nanocomposites for hyperthermia and drug delivery are summarized in this review. The structure and different heating and drug release mechanisms of this magnetic system are discussed.