Key advances of carboxymethyl cellulose in tissue engineering & 3D bioprinting applications

Efficient dual crosslinking of protein-in-polysaccharide bioink for biofabrication of cardiac tissue constructs

Myocardial infarction (MI) is a lethal cardiac disease that causes most of the mortality across the world. MI is a consequence of plaque in the arterial walls of heart, which eventually result in occlusion and ischemia to the myocardial tissues due to inadequate nutrient and oxygen supply. As an efficient alternative to the existing treatment strategies for MI, 3D bioprinting has evolved as an advanced tissue fabrication technique where the cell-laden bioinks are printed layer-by-layer to create functional cardiac patches. In this study, a dual crosslinking strategy has been utilized towards 3D bioprinting of myocardial constructs by using a combination of alginate and fibrinogen. Herein, pre-crosslinking of the physically blended alginate-fibrinogen bioinks with CaCl₂ enhanced the shape fidelity and printability of the printed structures. Physicochemical properties of the bioinks such as rheology, fibrin distribution, swelling ratio and degradation behaviour, were determined post-printing for only ionically crosslinked & dual crosslinked constructs and found to be ideal for bioprinting of cardiac constructs. Human ventricular cardiomyocytes (AC 16) exhibited a significant increase in cell proliferation on day 7 and 14 in AF-DMEM-20 mM CaCl₂ bioink when compared to A-DMEM-20 mM CaCl₂ (p < 0.05). Furthermore, myocardial patches containing neonatal ventricular rat myocytes (NVRM) showed >80 % viability and also expressed sarcomeric alpha actinin & connexin 43. These results indicate that the dual crosslinking strategy was cytocompatible and also possess the potential to be used for biofabrication of thick myocardial constructs for regenerative medicine applications.

Adsorption properties of cellulose/guar gum/biochar composite hydrogel for Cu2+, Co2+ and methylene blue

Herein, Typha angustifolia was used as a charcoal source and chemically modified with a strong oxidizing agent, potassium permanganate (KMnO₄), to obtain modified Typha angustifolia (MTC). Then, the green, stable and efficient CMC/GG/MTC composite hydrogel was successfully prepared by compounding MTC with carboxymethyl cellulose (CMC) and guar gum (GG) by free radical polymerization. Various variables that influence adsorption performance were explored, and optimal adsorption conditions were determined. The maximum adsorption capacity calculated from the Langmuir isotherm model was 805.45, 772.52, and 598.28 mg g^-1 for Cu²⁺, Co²⁺, and methylene blue (MB), respectively. The XPS results revealed that the main mechanism of removing pollutants by adsorbent is surface complexation and electrostatic attraction. After five adsorption-desorption cycles, the CMC/GG/MTC adsorbent still exhibited good adsorption and regeneration capacity. This study provides a low-cost, effective and simple method for preparation of hydrogels from modified biochar, which has excellent application potential in the removal of heavy metal ions and organic cationic dye contaminants from wastewater.

Global hotspots and emerging trends in 3D bioprinting research

Three-dimensional (3D) bioprinting is an advanced tissue engineering technique that has received a lot of interest in the past years. We aimed to highlight the characteristics of articles on 3D bioprinting, especially in terms of research hotspots and focus. Publications related to 3D bioprinting from 2007 to 2022 were acquired from the Web of Science Core Collection database. We have used VOSviewer, CiteSpace, and R-bibliometrix to perform various analyses on 3,327 published articles. The number of annual publications is increasing globally, a trend expected to continue. The United States and China were the most productive countries with the closest cooperation and the most research and development investment funds in this field. Harvard Medical School and Tsinghua University are the top-ranked institutions in the United States and China, respectively. Dr. Anthony Atala and Dr. Ali Khademhosseini, the most productive researchers in 3D bioprinting, may provide cooperation opportunities for interested researchers. Tissue Engineering Part A contributed the largest publication number, while Frontiers in Bioengineering and Biotechnology was the most attractive journal with the most potential. As for the keywords in 3D bioprinting, Bio-ink, Hydrogels (especially GelMA and Gelatin), Scaffold (especially decellularized extracellular matrix), extrusion-based bioprinting, tissue engineering, and in vitro models (organoids particularly) are research hotspots analyzed in the current study. Specifically, the research topics "new bio-ink investigation," "modification of extrusion-based bioprinting for cell viability and vascularization," "application of 3D bioprinting in organoids and in vitro model" and "research in personalized and regenerative medicine" were predicted to be hotspots for future research.

Magnetite carboxymethylcellulose as biological macromolecule-based absorbent for cationic dyes removal from environmental samples

In this study, magnetite carboxymethylcellulose (CMC@Fe₃O₄) composite as magnetic biological molecules were synthetized for the use as adsorbent to remove four types of cationic dyes, namely Methylene Blue, Rhodamine B, Malachite Green, and Methyl Violet from aqueous solution. The characteristic of the adsorbent was achieved by Fourier Transform Infrared Spectroscopy, Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction, Vibrating Sample Magnetometer and Thermal Gravimetric Analysis techniques. Besides, essential influencing parameters of dye adsorption; the solution pH, solution temperature, contact time, adsorbent concentration and initial dye dosage were studied. FESEM analysis showed the magnetic Fe₃O₄-TB, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂-NH₂ and CMC@Fe₃O₄ composites were in spherical shape, with average size of 43.0 nm, 92.5 nm, 134.0 nm and 207.5 nm, respectively. On the saturation magnetization (Ms), the results obtained were 55.931 emu/g, 34.557 emu/g, 33.236 emu/g and 11.884 emu/g. From the sorption modelling of Isotherms, Kinetics, and Thermodynamics, the adsorption capacity of dyes is (MB = 103.33 mg/g), (RB = 109.60 mg/g), (MG = 100.08 mg/g) and (MV = 107.78 mg/g). With all the adsorption processes exhibited as exothermic reactions. The regeneration and reusability of the synthetized biological molecules-based adsorbent was also assessed.

The influence of molecular weight of cellulose on the properties of carboxylic acid crosslinked cellulose hydrogels for biomedical and environmental applications

Hydrogels a three-dimensional network structure of hydrophilic polymers have gained significant interest in the field of biomedicine due to its high-water absorption properties and its resemblance to native extracellular matrix. However, the hydrogel's physicochemical properties are important in its ability to serve as a matrix in biomedical applications. The variations on the molecular weight of polymers on the preparation of crosslinked hydrogels may alter the properties. Different molecular weight carboxymethyl cellulose polymers were employed in this work to determine the effect of molecular weight on the physicochemical parameters of the hydrogel's crosslinking reaction. For this study, two distinct molecular weight carboxymethyl cellulose (CMC) polymers (M_w, 250,000 and 700,000) and various concentrations of crosslinker solution were used. The hydrogels were prepared through a chemical crosslinking reaction combining CMC and citric acid, which results in the formation of an ester bond between the two polymer chains. The crosslinking reaction is confirmed by Fourier transform infrared spectroscopy and total carboxyl content analysis. According to the physicochemical, thermal, and mechanical analysis, we have identified that 7 %, 9 % and 10 % citric acid showed the most promising hydrogels and found 7CMC hydrogel had superior quality. In vitro results demonstrated that the citric acid crosslinked CMC had excellent hemocompatibility and cytocompatibility.

Nanoemulsion carriers of porous γ-alumina modified by polyvinylpyrrolidone and carboxymethyl cellulose for pH-sensitive delivery of 5-fluorouracil

5-Fluorouracil (5-FU) is a cytotoxic drug with a low half-life. These features can cause some problems such as burst drug release and numerous side effects. In the present study, a pH-sensitive nanocomposite of polyvinylpyrrolidone (PVP)/carboxymethyl cellulose (CMC)/γ-alumina developed by using water in oil in water (W/O/W) double emulsion method. The fabricated emulsion has been employed as the 5-FU carrier to investigate its effects on drug half-life, side effects, drug loading efficiency (DLE), and drug entrapment efficiency (DEE). Analyzing the FTIR and XRD indicated the successful loading of 5-FU into the nanocarrier and affirmed the synthesized nanocomposite's chemical bonding and crystalline features. Furthermore, by using DLS and Zeta potential assessment, size and undersize distribution, as well as the stability of the drug-loaded nanocomposite were determined, which demonstrated the monodisperse and stable nanoparticles. Moreover, the nanocomposites with spherical shapes and homogeneous surfaces were shown in FE-SEM, which indicated good compatibility for the constituents of the nanocomposites. Moreover, by employing BET analysis the porosity has been investigated. Drug release pattern was studied, which indicated a controlled drug release behavior with above 96 h drug retention. Besides, the loading and entrapment efficiencies were obtained 44 % and 86 %, respectively. Furthermore, the curve fitting technique has been employed and the predominant release mechanism has been determined to evaluate the best-fitted kinetic models. MTT assay and flow cytometry assessment has been carried out to investigate the cytotoxic effects of the fabricated drug-loaded nanocomposite on MCF-7 and normal cells. The results showed enhanced cytotoxicity and late apoptosis for the PVP/CMC/γ-alumina/5-FU. Based on the MTT assay outcomes on normal cell lines (L929), which indicated above 90 % cell viability, the biocompatibility and biosafety of the synthesized nanocarrier have been confirmed. Moreover, due to the porosity of the PVP/CMC/γ-alumina, this nanocarrier can exploit from high specific surface area and be more sensitive to environmental conditions such as pH. These outcomes propose that the novel pH-sensitive PVP/CMC/γ-alumina nanocomposite can be a potential candidate for drug delivery applications, especially for cancer therapy.

Classification, processing, and applications of bioink and 3D bioprinting: A detailed review

With the advancement in 3D bioprinting technology, cell culture methods can design 3D environments which are both, complex and physiologically relevant. The main component in 3D bioprinting, bioink, can be split into various categories depending on the criterion of categorization. Although the choice of bioink and bioprinting process will vary greatly depending on the application, general features such as material properties, biological interaction, gelation, and viscosity are always important to consider. The foundation of 3D bioprinting is the exact layer-by-layer implantation of biological elements, biochemicals, and living cells with the spatial control of the implantation of functional elements onto the biofabricated 3D structure. Three basic strategies underlie the 3D bioprinting process: autonomous self-assembly, micro tissue building blocks, and biomimicry or biomimetics. Tissue engineering can benefit from 3D bioprinting in many ways, but there are still numerous obstacles to overcome before functional tissues can be produced and used in clinical settings. A better comprehension of the physiological characteristics of bioink materials and a higher level of ability to reproduce the intricate biologically mimicked and physiologically relevant 3D structures would be a significant improvement for 3D bioprinting to overcome the limitations.

Research progress in decellularized extracellular matrix hydrogels for intervertebral disc degeneration

As one of the most common clinical disorders, low back pain (LBP) influences patient quality of life and causes substantial social and economic burdens. Many factors can result in LBP, the most common of which is intervertebral disc degeneration (IDD). The progression of IDD cannot be alleviated by conservative or surgical treatments, and gene therapy, growth factor therapy, and cell therapy have their own limitations. Recently, research on the use of hydrogel biomaterials for the treatment of IDD has garnered great interest, and satisfactory treatment results have been achieved. This article describes the classification of hydrogels, the methods of decellularized extracellular matrix (dECM) production and the various types of gel formation. The current research on dECM hydrogels for the treatment of IDD is described in detail in this article. First, an overview of the material sources, decellularization methods, and gel formation methods is given. The focus is on research performed over the last three years, which mainly consists of bovine and porcine NP tissues, while for decellularization methods, combinations of several approaches are primarily used. dECM hydrogels have significantly improved mechanical properties after the polymers are cross-linked. The main effects of these gels include induction of stem cell differentiation to intervertebral disc (IVD) cells, good mechanical properties to restore IVD height after polymer cross-linking, and slow release of exosomes. Finally, the challenges and problems still faced by dECM hydrogels for the treatment of IDD are summarised, and potential solutions are proposed. This paper is the first to summarise the research on dECM hydrogels for the treatment of IDD and aims to provide a theoretical reference for subsequent studies.

Physicochemical Characterization, Biocompatibility, and Antibacterial Properties of CMC/PVA/Calendula officinalis Films for Biomedical Applications

This study reports a carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) composite film that incorporates Calendula officinalis (CO) extract for biomedical applications. The morphological, physical, mechanical, hydrophilic, biological, and antibacterial properties of CMC/PVA composite films with various CO concentrations (0.1%, 1%, 2.5%, 4%, and 5%) are fully investigated using different experiments. The surface morphology and structure of the composite films are significantly affected by higher CO concentrations. X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR) analyses confirm the structural interactions among CMC, PVA, and CO. After CO is incorporated, the tensile strength and elongation upon the breaking of the films decrease significantly. The addition of CO significantly reduces the ultimate tensile strength of the composite films from 42.8 to 13.2 MPa. Furthermore, by increasing the concentration of CO to 0.75%, the contact angle is decreased from 15.8° to 10.9°. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay reveals that the CMC/PVA/CO-2.5% and CMC/PVA/CO-4% composite films are non-cytotoxic to human skin fibroblast cells, which is favorable for cell proliferation. Remarkably, 2.5% and 4% CO incorporation significantly improve the inhibition ability of the CMC/PVA composite films against Staphylococcus aureus and Escherichia coli. In summary, CMC/PVA composite films containing 2.5% CO exhibit the functional properties for wound healing and biomedical engineering applications.

Application of Hydrogels as Three-Dimensional Bioprinting Ink for Tissue Engineering

The use of three-dimensional bioprinting technology combined with the principle of tissue engineering is important for the construction of tissue or organ regeneration microenvironments. As a three-dimensional bioprinting ink, hydrogels need to be highly printable and provide a stiff and cell-friendly microenvironment. At present, hydrogels are used as bioprinting inks in tissue engineering. However, there is still a lack of summary of the latest 3D printing technology and the properties of hydrogel materials. In this paper, the materials commonly used as hydrogel bioinks; the advanced technologies including inkjet bioprinting, extrusion bioprinting, laser-assisted bioprinting, stereolithography bioprinting, suspension bioprinting, and digital 3D bioprinting technologies; printing characterization including printability and fidelity; biological properties, and the application fields of bioprinting hydrogels in bone tissue engineering, skin tissue engineering, cardiovascular tissue engineering are reviewed, and the current problems and future directions are prospected.

Stability improvement of carboxymethyl cellulose/chitosan complex beads by thermal treatment

Carboxymethyl cellulose (CMC) and chitosan (CHI) are two well-known natural polymer derivatives, as such the CMC@CHI complex beads fulfill many requirements for bio-related and safety-required applications. However, poor mechanical properties of CMC@CHI beads hinder their applications. We managed to improve the beads stability by a simple thermal treatment during the bead preparation. The effects of temperature, changing from 25 °C to 75 °C, on the stability of the formed beads were investigated. The morphology, diameter, shell thickness and structure of the beads treated at different temperature were analyzed using SEM, XPS and FTIR. The mechanical test and swelling experiments showed that the thermal treatment enhanced the bead's ability to withstand pressure and swelling. The beads treated at 75 °C showed the best pressure resistance, while the beads treated at 55 °C exhibited the highest swelling capability without losing integrity. This method is convenient to implement, not only improves the stability, but also controls the swelling capacity and mechanical properties of the beads, which are important for their potential applications in adsorption and controlled release. More importantly, this work offered insights on the effects of thermal treatment on the complexation process of the two polysaccharide molecular chains.

Advances in electrospinning and 3D bioprinting strategies to enhance functional regeneration of skeletal muscle tissue

Skeletal muscles are essential for body movement, and the loss of motor function due to volumetric muscle loss (VML) limits the mobility of patients. Current therapeutic approaches are insufficient to offer complete functional recovery of muscle damages. Tissue engineering provides viable ways to fabricate scaffolds to regenerate damaged tissues. Hence, tissue engineering options are explored to address existing challenges in the treatment options for muscle regeneration. Electrospinning is a widely employed fabrication technique to make muscle mimetic nanofibrous scaffolds for tissue regeneration. 3D bioprinting has also been utilized to fabricate muscle-like tissues in recent times. This review discusses the anatomy of skeletal muscle, defects, the healing process, and various treatment options for VML. Further, the advanced strategies in electrospinning of natural and synthetic polymers are discussed, along with the recent developments in the fabrication of hybrid scaffolds. Current approaches in 3D bioprinting of skeletal muscle tissues are outlined with special emphasis on the combination of electrospinning and 3D bioprinting towards the development of fully functional muscle constructs. Finally, the current challenges and future perspectives of these convergence techniques are discussed.

Modulation of bioactive calcium phosphate micro/nanoparticle size and shape during in situ synthesis of photo-crosslinkable gelatin methacryloyl based nanocomposite hydrogels for 3D bioprinting and tissue engineering

Background

The gelatin-methacryloyl (GelMA) polymer suffers shape fidelity and structural stability issues during 3D bioprinting for bone tissue engineering while homogeneous mixing of reinforcing nanoparticles is always under debate.

Method

In this study, amorphous calcium phosphates micro/nanoparticles (CNP) incorporated GelMA is synthesized by developing specific sites for gelatin structure-based nucleation and stabilization in a one-pot processing. The process ensures homogenous distribution of CNPs while different concentrations of gelatin control their growth and morphologies. After micro/nanoparticles synthesis in the gelatin matrix, methacrylation is carried out to prepare homogeneously distributed CNP-reinforced gelatin methacryloyl (CNP GelMA) polymer. After synthesis of CNP and CNP GelMA gel, the properties of photo-crosslinked 3D bioprinting scaffolds were compared with those of the conventionally fabricated ones.

Results

The shape (spindle to spherical) and size (1.753 μm to 296 nm) of the micro/nanoparticles in the GelMA matrix are modulated by adjusting the gelatin concentrations during the synthesis. UV cross-linked CNP GelMA (using Irgacure 2955) has significantly improved mechanical (three times compressive strength), 3D printability (160 layers, 2 cm self-standing 3D printed height) and biological properties (cell supportiveness with osteogenic differentiation). The photo-crosslinking becomes faster due to better methacrylation, facilitating continuous 3D bioprinting or printing.

Conclusion

For 3D bioprinting using GelMA like photo cross-linkable polymers, where structural stability and homogeneous control of nanoparticles are major concerns, CNP GelMA is beneficial for even bone tissue regeneration within short period.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00301-6.

Quick and Easy Covalent Grafting of Sulfonated Dyes to CMC: From Synthesis to Colorimetric Sensing Applications

Carboxymethyl cellulose, the most promising cellulose-derivatives, pulls together low cost, abundancy, biocompatibility, unique properties and, unlike the precursor, chemical reactivity. This latter aspect arouses the curiosity of chemists around the possibility of chemical modification and the production of interesting functional materials. Here, a two-step reaction is proposed for the covalent anchoring of a wide variety of molecules containing sulfonic groups to CMC. The strength points of the proposed pathway have to be found in the quick and easy reactions and workup that allow to obtain ready-to-use functional materials with very high yields. Having in this case exploited a pH-sensitive dye as a sulfonated molecule, the functional material is an interesting candidate for the development of colorimetric miniaturized sensors via the following drop-casting deposition: once optimized sensors preparation by design of experiments, an example of application on real samples is reported.

Sulfated carboxymethyl cellulose and carboxymethyl κ-carrageenan immobilization on 3D-printed poly-ε-caprolactone scaffolds differentially promote pre-osteoblast proliferation and osteogenic activity

The lack of bioactivity in three-dimensional (3D)-printing of poly-є-caprolactone (PCL) scaffolds limits cell-material interactions in bone tissue engineering. This constraint can be overcome by surface-functionalization using glycosaminoglycan-like anionic polysaccharides, e.g., carboxymethyl cellulose (CMC), a plant-based carboxymethylated, unsulfated polysaccharide, and κ-carrageenan, a seaweed-derived sulfated, non-carboxymethylated polysaccharide. The sulfation of CMC and carboxymethylation of κ-carrageenan critically improve their bioactivity. However, whether sulfated carboxymethyl cellulose (SCMC) and carboxymethyl κ-carrageenan (CM-κ-Car) affect the osteogenic differentiation potential of pre-osteoblasts on 3D-scaffolds is still unknown. Here, we aimed to assess the effects of surface-functionalization by SCMC or CM-κ-Car on the physicochemical and mechanical properties of 3D-printed PCL scaffolds, as well as the osteogenic response of pre-osteoblasts. MC3T3-E1 pre-osteoblasts were seeded on 3D-printed PCL scaffolds that were functionalized by CM-κ-Car (PCL/CM-κ-Car) or SCMC (PCL/SCMC), cultured up to 28 days. The scaffolds’ physicochemical and mechanical properties and pre-osteoblast function were assessed experimentally and by finite element (FE) modeling. We found that the surface-functionalization by SCMC and CM-κ-Car did not change the scaffold geometry and structure but decreased the elastic modulus. Furthermore, the scaffold surface roughness and hardness increased and the scaffold became more hydrophilic. The FE modeling results implied resilience up to 2% compression strain, which was below the yield stress for all scaffolds. Surface-functionalization by SCMC decreased Runx2 and Dmp1 expression, while surface-functionalization by CM-κ-Car increased Cox2 expression at day 1. Surface-functionalization by SCMC most strongly enhanced pre-osteoblast proliferation and collagen production, while CM-κ-Car most significantly increased alkaline phosphatase activity and mineralization after 28 days. In conclusion, surface-functionalization by SCMC or CM-κ-Car of 3D-printed PCL-scaffolds enhanced pre-osteoblast proliferation and osteogenic activity, likely due to increased surface roughness and hydrophilicity. Surface-functionalization by SCMC most strongly enhanced cell proliferation, while CM-κ-Car most significantly promoted osteogenic activity, suggesting that surface-functionalization by CM-κ-Car may be more promising, especially in the short-term, for in vivo bone formation.

Synthesis of keto-biomacromolecule derivatives by oxidation of carboxymethyl cellulose using alkaline hexacyanoferrate (III) for alternative applications in biotechnology

The oxidation kinetics of polysaccharides involving carboxymethyl cellulose (CMC) by several oxidizing agent have been investigated in more detail with shedding some light on the synthesis of their respective keto-derivatives as oxidation precursor products. However, the literature survey indicated that no reports have appeared on the oxidation kinetics of CMC or the synthesis of keto-CMC using hexacyanoferrate (III) ion. Therefore, a lack of information on the transfer of electron process in the rate-determining stage as well as the nature of such keto-derivatives obtained as a result of polysaccharides oxidation using various oxidants in aqueous solutions. Accordingly, the present study presents synthesis of diketo CMC as a biomacromolecule derivative using potassium ferricyanide in alkaline media. The experimental results revealed the formation of either monoketo or diketo-derivatives of CMC based on initial molar ratio between the two reactants. The formation of such keto derivatives was confirmed by the reaction of the oxidation products with both 2,4-dinitrophenyl hydrazine and hydroxyl amine as well as FTIR spectra. The reaction kinetics of oxidation showed unity order in [Fe(CN)₆^3-] and fractional first-orders with respect to both [CMC] and [OH^-].The obedience of the reaction behavior to the Michael-Menten kinetics was indicative to the formation of 1:1 intermediate complex prior to the rate-determining step as a pathway route for oxidation.

Polysaccharide Based Implantable Drug Delivery: Development Strategies, Regulatory Requirements, and Future Perspectives

Implantable drug delivery systems advocate a wide array of potential benefits, including effective administration of drugs at lower concentrations and fewer side-effects whilst increasing patient compliance. Amongst several polymers used for fabricating implants, biopolymers such as polysaccharides are known for modulating drug delivery attributes as desired. The review describes the strategies employed for the development of polysaccharide-based implants. A comprehensive understanding of several polysaccharide polymers such as starch, cellulose, alginate, chitosan, pullulan, carrageenan, dextran, hyaluronic acid, agar, pectin, gellan gum is presented. Moreover, biomedical applications of these polysaccharide-based implantable devices along with the recent advancements carried out in the development of these systems have been mentioned. Implants for the oral cavity, nasal cavity, bone, ocular use, and antiviral therapy have been discussed in detail. The regulatory considerations with respect to implantable drug delivery has also been emphasized in the present work. This article aims to provide insights into the developmental strategies for polysaccharide-based implants.

The Fabrication of Alginate–Carboxymethyl Cellulose-Based Composites and Drug Release Profiles

Recently, hydrogels based on natural water-soluble polysaccharides have attracted more and more attention due to their favorable characteristics. The high water-holding capacity, lack of toxicity, and biodegradability of such hydrogels make it possible to develop new materials on their basis for biotechnological, biomedical, pharmacological, and medical purposes. Sodium alginate is a non-toxic natural polysaccharide found in marine algae. It is capable of forming solid gels under the action of polyvalent cations that cross-link polysaccharide chains. Alginate-based products are popular in many industries, including food processing, pharmaceutical, and biomedical applications. Cellulose is the most abundant, renewable, and natural polymer on Earth, and it is used for various industrial and biomedical applications. Carboxymethyl cellulose (CMC) is useful in pharmaceutical, food, and non-food industries such as tablets, ice cream, drinks, toothpaste, and detergents. In this review, various methods for the preparation of the compositions based on sodium alginate and CMC using different crosslinking agents have been collected for the first time. Additionally, the drug release profile from such polymer matrixes was analyzed.

Plant Polysaccharides in Engineered Pharmaceutical Gels

Hydrogels are a great ally in the pharmaceutical and biomedical areas. They have a three-dimensional polymeric structure that allows the swelling of aqueous fluids, acting as an absorbent, or encapsulating bioactive agents for controlled drug release. Interestingly, plants are a source of biogels, specifically polysaccharides, composed of sugar monomers. The crosslinking of these polymeric chains forms an architecture similar to the extracellular matrix, enhancing the biocompatibility of such materials. Moreover, the rich hydroxyl monomers promote a hydrophilic behavior for these plant-derived polysaccharide gels, enabling their biodegradability and antimicrobial effects. From an economic point of view, such biogels help the circular economy, as a green material can be obtained with a low cost of production. As regards the bio aspect, it is astonishingly attractive since the raw materials (polysaccharides from plants-cellulose, hemicelluloses, lignin, inulin, pectin, starch, guar, and cashew gums, etc.) might be produced sustainably. Such properties make viable the applications of these biogels in contact with the human body, especially incorporating drugs for controlled release. In this context, this review describes some sources of plant-derived polysaccharide gels, their biological function, main methods for extraction, remarkable applications, and properties in the health field.

Development of hydrogel based on Carboxymethyl cellulose/poly(4-vinylpyridine) for controlled releasing of fertilizers

A novel Carboxymethyl cellulose (CMC) and poly (4-vinylpyridine) (P4VP) hydrogel system is synthesized with different ratios, in the presence of cross-linker N, N,- methylene bis-acrylamide (MBA). The hydrogel is characterized via FTIR spectroscopy, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The FTIR results showed a strong interaction between both CMC, P4VP and the loaded fertilizer. The water uptake of the hydrogel was evaluated by swelling tests under variations in pH, biodegradability was investigated in soil to simulate real-world conditions. To determine the best release behavior of urea and calcium nitrate from the hydrogel, fertilizers were loaded with different ratios onto the hydrogel during its formation. Fertilizers release was followed by Atomic absorption spectroscopy to study the release of calcium nitrate and urea. Release kinetic parameters were obtained based on different mathematical models as Zero order, First order, Korsmeyer-Peppas and Higuchi models. The suitable proportionality between the mathematical models used and the fertilizers release was determined based on the correlation coefficients (R2). According to Zero order model urea release showed independent concentration. Based on Korsmeyer-Pappas and Higuchi models with high n value and R2 equals to 0.97. Compared to urea, Ca2+, Zero order and Higuchi have been ignored due to their poor correlation coefficients values as proportion with Ca2+ fertilizer release.

A Guide to Polysaccharide-Based Hydrogel Bioinks for 3D Bioprinting Applications

Three-dimensional (3D) bioprinting is an innovative technology in the biomedical field, allowing the fabrication of living constructs through an approach of layer-by-layer deposition of cell-laden inks, the so-called bioinks. An ideal bioink should possess proper mechanical, rheological, chemical, and biological characteristics to ensure high cell viability and the production of tissue constructs with dimensional stability and shape fidelity. Among the several types of bioinks, hydrogels are extremely appealing as they have many similarities with the extracellular matrix, providing a highly hydrated environment for cell proliferation and tunability in terms of mechanical and rheological properties. Hydrogels derived from natural polymers, and polysaccharides, in particular, are an excellent platform to mimic the extracellular matrix, given their low cytotoxicity, high hydrophilicity, and diversity of structures. In fact, polysaccharide-based hydrogels are trendy materials for 3D bioprinting since they are abundant and combine adequate physicochemical and biomimetic features for the development of novel bioinks. Thus, this review portrays the most relevant advances in polysaccharide-based hydrogel bioinks for 3D bioprinting, focusing on the last five years, with emphasis on their properties, advantages, and limitations, considering polysaccharide families classified according to their source, namely from seaweed, higher plants, microbial, and animal (particularly crustaceans) origin.

Polysaccharides, as biological macromolecule-based scaffolding biomaterials in cornea tissue engineering: A review

Corneal-related diseases and injuries are the leading causes of vision loss, estimated to affect over 10 million people worldwide. Currently, cadaveric corneal grafts are considered the gold standard of treatment to restore cornea-related vision. However, this treatment modality faces different challenges such as donor shortage and graft failure. Therefore, the need for alternative solutions continues to grow. Tissue engineering has dramatically progressed to produce artificial cornea implants in order to repair, regenerate, or replace the damaged cornea. In this regard, a variety of polysaccharides such as cellulose, chitosan, alginate, agarose, and hyaluronic acid have been widely explored as scaffolding biomaterials for the production of tissue-engineered cornea. These polymers are known for their excellent biocompatibility, versatile properties, and processability. Recent progress and future perspectives of polysaccharide-based biomaterials in cornea tissue engineering is reviewed here.

Recent Advances in 3D Bioprinting: A Review of Cellulose-Based Biomaterials Ink

Cellulose-based biodegradable hydrogel proves to be excellently suitable for the medical and water treatment industry based on the expressed properties such as its flexible structure and broad compatibility. Moreover, their potential to provide excellent waste management from the unutilized plant has triggered further study on the advanced biomaterial applications. To extend the use of cellulose-based hydrogel, additive manufacturing is a suitable technique for hydrogel fabrication in complex designs. Cellulose-based biomaterial ink used in 3D bioprinting can be further used for tissue engineering, drug delivery, protein study, microalgae, bacteria, and cell immobilization. This review includes a discussion on the techniques available for additive manufacturing, bio-based material, and the formation of a cellulose-based hydrogel.

Adaptive injectable carboxymethyl cellulose/poly (γ-glutamic acid) hydrogels promote wound healing

The clinical acceleration of skin autogenous healing remains a great challenge, especially in the early stage after injury. In this work, a novel directly injectable hydrogel with high self-adaptability is designed as a provisional matrix to close the apposition of wound edges, using carboxymethyl cellulose and poly (γ-glutamic acid) through Schiff-base reaction. Benefiting from the dynamic covalent cross-linking structure, the functional biodegradable hydrogels are easy to prepare (gel time 5-180 s), demonstrating adequate mechanical strength (40-120 kPa), anti-fatigue abilities, and rapid self-healing (5-10 min at skin defect). Furthermore, the hydrogels exhibit biocompatibility and proliferation-promoting activity with murine fibroblasts. In the full-thickness dermal animal models, it significantly promoted collagen deposition, skin-function restoration, and VEGF expression. This hydrogel shows potential as a dressing available for skin regeneration during the healing of dermal injuries.

A Synthetic Gene Library Yields a Previously Unknown Glycoside Phosphorylase That Degrades and Assembles Poly-β-1,3-GlcNAc, Completing the Suite of β-Linked GlcNAc Polysaccharides

The considerable utility of glycoside phosphorylases (GPs) has led to substantial efforts over the past two decades to expand the breadth of known GP activities. Driven largely by the increase of available genomic DNA sequence data, the gap between the number of sequences in the carbohydrate active enzyme database (CAZy DB) and its functionally characterized members continues to grow. This wealth of sequence data presented an exciting opportunity to explore the ever-expanding CAZy DB to discover new GPs with never-before-described functionalities. Utilizing an in silico sequence analysis of CAZy family GH94, we discovered and then functionally and structurally characterized the new GP β-1,3-N-acetylglucosaminide phosphorylase. This new GP was sourced from the genome of the cell-wall-less Mollicute bacterium, Acholeplasma laidlawii and was found to synthesize β-1,3-linked N-acetylglucosaminide linkages. The resulting poly-β-1,3-N-acetylglucosamine represents a new, previously undescribed biopolymer that completes the set of possible β-linked GlcNAc homopolysaccharides together with chitin (β-1,4) and PNAG (poly-β-1,6-N-acetylglucosamine). The new biopolymer was denoted acholetin, a combination of the genus Acholeplasma and the polysaccharide chitin, and the new GP was thus denoted acholetin phosphorylase (AchP). Use of the reverse phosphorolysis action of AchP provides an efficient method to enzymatically synthesize acholetin, which is a new biodegradable polymeric material.

Designer DNA biomolecules as a defined biomaterial for 3D bioprinting applications

DNA has excellent features such as the presence of functional and targeted molecular recognition motifs, tailorability, multifunctionality, high-precision molecular self-assembly, hydrophilicity, and outstanding biocompatibility. Due to these remarkable features, DNA has emerged as a leading next-generation biomaterial of choice to make hydrogels by self-assembly. In recent times, novel routes for the chemical synthesis of DNA, advances in tailorable designs, and affordable production ways have made DNA as a building block material for various applications. These advanced features have made researchers continuously explore the interesting properties of pure and hybrid DNA for 3D bioprinting and other biomedical applications. This review article highlights the topical advancements in the use of DNA as an ideal bioink for the bioprinting of cell-laden three-dimensional tissue constructs for regenerative medicine applications. Various bioprinting techniques and emerging design approaches such as self-assembly, nucleotide sequence, enzymes, and production cost to use DNA as a bioink for bioprinting applications are described. In addition, various types and properties of DNA hydrogels such as stimuli responsiveness and mechanical properties are discussed. Further, recent progress in the applications of DNA in 3D bioprinting are emphasized. Finally, the current challenges and future perspectives of DNA hydrogels in 3D bioprinting and other biomedical applications are discussed.

Conductive graphene coated carboxymethyl cellulose hybrid fibers with polymeric ionic liquids as intermediate

In this study, a kind of polymeric ionic liquid (PIL) called PIL-Cl was synthesized and modified to obtain conductive graphene coated carboxymethyl cellulose hybrid fibers. Carboxymethyl cellulose (CMC) was formed into fibers by wet spinning assisted with PILCl. Co-precipitation test of CMC and PIL-Cl demonstrated that PIL-Cl could precipitate with CMC through strong electrostatic interaction and molar ratio of CMC and PIL-Cl (calculated in repeating units) would affect the formation of precipitation. Secondly, modified PIL-Cl named PIL-Ac was used as an intermediate connecting CMC fiber and graphene to fabricate conductive CMC/PIL/graphene fibers. A series of tests were performed on CMC/PIL/graphene fibers, including Raman spectroscopy, scanning electron microscopy and conductivity test. The results showed that PIL-Cl could help form CMC fiber, and PIL-Ac could functionalize it and make it conductive.

Natural Plant Tissue with Bioinspired Nano Amyloid and Hydroxyapatite as Green Scaffolds for Bone Regeneration

Bone defects have been increasingly prevalent around the globe and traditional bone substitutes are constantly limited by low abundance and biosafety due to their animal-based resources. Plant-based scaffolds are currently studied as a green candidate but the bioinertia of cellulose to mammalian cells leads to uncertain bone regeneration. Inspired by the cross-kingdom adhesion of plants and bacteria, this work proposes a concept of a novel plant bone substitute, involving coating decellularized plant with nano amyloids and nano hydroxyapatites, to bridge the plant scaffold and animal tissue regeneration. Natural microporosity of plants can guide alignment of mammalian cells into various organ-like structures. Taking advantage of the bioactive nano amyloids, the scaffolds drastically promote cell adhesion, viability, and proliferation. The enhanced bio-affinity is elucidated as positively charged nano amyloids and serum deposition on the nanostructure. Nano-hydroxyapatite crystals deposited on amyloid further prompt osteogenic differentiation of pre-osteoblasts. In vivo experiments prove successful trabeculae regeneration in the scaffold. Such a hierarchical design leverages the dedicated microstructure of natural plants and high bioactivity of nano amyloid/hydroxyapatite coatings, and addresses the abundant resource of bone substitutes. Not limited to their current application, plant materials functionalized with nano amyloid/hydroxyapatite coatings allow many cross-kingdom tissue engineering and biomedical applications.

3D printed carboxymethyl cellulose scaffolds for autologous growth factors delivery in wound healing

This work aims to use carboxymethyl cellulose (CMC) as main structural and functional component of 3D printed scaffolds for healing of diabetic wounds. Differently from previous inks involving small contents in CMC, herein sterile (steam-heated) concentrated CMC solely dispersions (10-20%w/v) were screened regarding printability and fidelity properties. CMC (15%w/v)-citric acid inks showed excellent self-healing rheological properties and stability during storage. CMC scaffolds loaded with platelet rich plasma (PRP) sustained the release of relevant growth factors. CMC scaffolds both with and without PRP promoted angiogenesis in ovo, stem cell migration in vitro, and wound healing in a diabetic model in vivo. Transparent CMC scaffolds allowed direct monitoring of bilateral full-thickness wounds created in rat dorsum. CMC scaffolds facilitated re-epithelialization, granulation, and angiogenesis in full-thickness skin defects, and the performance was improved when combined with PRP. Overall, CMC is pointed out as outstanding component of active dressings for diabetic wounds.

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.