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The controlled delivery of the desired bioactive molecules is required to achieve the maximum therapeutic effects with minimum side effects. Biopolymer-based hydrogels are ideal platforms for delivering the desired molecules owing to their superior biocompatibility, biodegradability, and low-immune response. However, the prolonged delivery of the drugs through biopolymer-based hydrogels is restricted due to their weak mechanical stability. We developed mechanically tough and biocompatible hydrogels to address these limitations using carboxymethyl chitosan, sodium alginate, and nanocellulose for sustained drug delivery. The hydrogels were cross-linked through calcium ions to enhance their mechanical strength. Nanocellulose-added hydrogels exhibited improved mechanical strength (Young's modulus; 23.36 → 30.7 kPa, Toughness; 1.39 → 5.65 MJm -3 ) than pure hydrogels. The composite hydrogels demonstrated increased recovery potential (66.9 → 84.5 %) due to the rapid reformation of damaged polymeric networks. The hydrogels were stable in an aqueous medium and demonstrated reduced swelling potential. The hydrogels have no adverse effects on embryonic murine fibroblast (3 T3), showing their biocompatibility. No bacterial growth was observed in hydrogels-treated groups, indicating their antibacterial characteristics. The sustained drug released was observed from nanocellulose-assisted hydrogel scaffolds compared to the pure polymer hydrogel scaffold. Thus, hydrogels have potential and could be used as a sustained drug carrier., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Bacterial cellulose (BC), an extracellular polysaccharide, is a versatile biopolymer due to its intrinsic physicochemical properties, broad-spectrum applications, and remarkable achievements in different fields, especially in the biomedical field. Presently, the focus of BC-related research is on the development of scaffolds containing other materials for in-vitro and in-vivo biomedical applications. To this end, prime research objectives concern the biocompatibility of BC and the development of three-dimensional (3D) BC-based scaffolds. This review summarizes the techniques used to develop 3D BC scaffolds and discusses their potential merits and limitations. In addition, we discuss the various biomedical applications of BC-based scaffolds for which the 3D BC matrix confers desired structural and conformational features. Overall, this review provides comprehensive coverage of the idea, requirements, synthetic strategies, and current and prospective applications of 3D BC scaffolds, and thus, should be useful for researchers working with polysaccharides, biopolymers, or composite materials., (Copyright © 2022. Published by Elsevier B.V.)

To achieve a three-dimensional (3D) microenvironment for complex tissue regeneration is a great challenge when developing biomaterials as artificial extracellular matrix (ECM) with properties similar to that of native tissue. Polysaccharide-based hydrogel shows great potential as ECM in the regeneration of damaged tissues or reconstruction of organs, demonstrating properties similar to those of native ECM. Extrusion 3D printing of cell-free or cell-loaded hydrogel ink has led to a more sophisticated fabrication of the desired compositions and architectures for tissue engineering applications. The development of stable cell-free and cell-loaded hydrogel inks with optimal physicochemical properties and biocompatibility is also a major concern in direct-write extrusion-based 3D printing. In this study, carboxylated cellulose nanocrystals (cCNCs) were prepared using ammonium persulfate, where transmission electron microscopy, Fourier-transform infrared spectroscopy, and x-ray diffraction analyses confirmed their successful preparation. Further, the effect of cCNCs (-COOH) and/or xanthan gum (XG) (-COOH) was evaluated on the rheological behavior of the sodium alginate (SA) hydrogel matrix. The incorporation of cCNCs and XG manipulated the flow and shear-thinning behavior of the hydrogel inks, thereby improving the printing ability. The results showed good rheological properties, post-printing fidelity, and dynamic mechanical properties under compression of the developed hydrogel inks. Furthermore, good viability of the human skin fibroblast (CCD-986Sk) cells on bulk hydrogels (hydrogel inks) was observed, as demonstrated by both qualitative and quantitative cell analyses. The use of cCNCs and XG in SA hydrogel inks provides a primary insight for further improvement in designing 3D bioprintable hydrogel inks.

We report the development of halloysite nanotubes (HNTs)/carboxylated-cellulose nanocrystals (cCNCs) - reinforced and ionically-crosslinked k-carrageenan (k-CG)/xanthan gum (XG) hydrogels. In this study, cCNCs were extracted from microcrystalline cellulose using ammonium persulfate and exhibit 'spindle-like' nanocrystals with approximate diameter of 15-30 nm and length of 30-120 nm. The freeze-dried hydrogels showed highly porous microstructure with good pore-interconnectivity. Further, tunable swelling ratio and in vitro degradation rate of hydrogels under physiological condition (pH 7.4 PBS, 37 °C) were observed. In wet or dry states, the dynamic mechanical analysis of kCXGHN20cCN20 hydrogel showed significantly improved compressive strengths (at 50% strain: 8.1 ± 1.35 kPa or 81.33 ± 1.66 kPa, whereas at 70% strain: 11.84 ± 0.61 kPa or 120.7 ± 1.16 kPa) when reinforced with HNTs (20 wt%)/cCNCs (20 wt%), respectively. The stiffness values are reported at different compressive strains. All hydrogels showed excellent attachment and proliferation of human skin fibroblasts (CCD-986Sk) cells on hydrogels for 7 and 14 days of culture periods. The results showed that these hydrogels may have potential application in soft tissue engineering., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The frequent use of antibiotics against microbial infections may lead to the emergence of antibiotic resistant microbial strains. To overcome these microbial strains, we need to fabricate alternative materials which can handle them. It is for this reason, we have fabricated cellulose (CE) based filter paper (FP) composite scaffolds comprising of adsorbed chitosan (CS) and sliver (Ag) nanoparticles (NPs). The AgNPs are incorporated in the CS layer of the composite scaffold. Prior to evaluate the efficacy of the scaffolds against gram positive and gram negative bacterial strains, the scaffolds were characterized for the presence of the Ag NPs with field emission scanning electron microscope (FE-SEM), fourier transform infrared (FTIR) spectroscopy and x-ray diffractometer (XRD). These techniques confirmed the presence of Ag NPs in the composite scaffold. The biocompatibility of the scaffolds was assessed by subjecting pristine FP, CS adsorbed FP (CS-FP) and Ag loaded CS-FP (Ag-CS-FP) composite scaffolds to in vitro studies. From the data obtained, it was observed that NIH3T3 fibroblastic cells adhered and proliferated onto all the scaffolds. Furthermore, the scaffolds exhibited good antibacterial activity against both strains of bacteria. It is, therefore, concluded that these scaffolds could find potential application in biomedical field, particularly as a wound dressing agent., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Cellulose nanocrystals (CNCs) reinforced, bionanocomposite (BNC) has shown great potential in tissue engineering and drug delivery applications due to the low toxicity, low density, and high aspect ratio. In this work, BNC hydrogels reinforced with CNCs were fabricated from xanthan (XG) solutions and chitosan (CS) in presence of green acidifying agent through electrostatic and hydrogen bonding interactions. As developed BNC hydrogels were characterized for complex formation, morphology, and mechanical behavior. The mechanical performance of BNC hydrogels was improved significantly as increased CNC content (from 2 to 10wt%). 5-Flurouracil as model chemotherapeutic agent was loaded into these BNC hydrogels for evaluating their drug release properties. The BNC hydrogels showed excellent cytocompatability and ability to release of chemotherapeutic agent that shows the suitability to be used in tissue engineering as well as drug delivery applications., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds were fabricated by using freeze casting and freeze drying method. In this study, the effect of crosslinking agents such as calcium chloride, orthophosphoric acid, and borax on morphological, structural, thermal, mechanical, and cytocompatibility (cell adhesion and proliferation) properties was investigated. The results showed that the change in type of crosslinking agent significantly changed the properties of the hybrid scaffolds. Based on this study, borax-crosslinked hybrid scaffold showed good fibrous porous structure with high porosity (95.2%), highest water uptake capacity, good thermal stability, mechanical stability (storage modulus), and in vitro cell adhesion and proliferation with fibroblast (NIH3T3) cells. This primarily research study explores the way for further use of this crosslinking agent to design and fabricate scaffolds for tissue engineering applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this study, the structure and properties of an organic-inorganic composite material prepared from cellulose doped with fine particles of silver iodide (AgI) were examined. The preparation of the composite involved the complexation of cellulose with polyiodide ions, such as I- and 13-, by immersion in iodine/potassium iodide (I2/KI: 0.2, 0.4, 0.6, 0.8, 1.0 M) or potassium iodide (KI: 0.6, 1.2, 1.8, 2.4, 3.0 M) aqueous solutions followed by reaction in a silver nitrate (AgNO3:1.0 M) aqueous solution. These procedures resulted in the in situ formation of fine β-AgI particles within the cellulose matrix. The characteristics and conductivities of prepared cellulose/silver iodide (AgI) nanocomposite films with different I2/KI and KI concentrations were investigated. AgI particle formation and aggregation increased on increasing I2/KI and KI concentrations as determined by SEM. X-ray results showed that KI could penetrate the cellulose crystal region and form AgI particles. The electrical conductivities of nanocomposite films treated with KI were higher than that of I2/KI at < 1.0 M of I2/KI and 3 M of KI, although the weight gain by AgI formation was lower than that of I2/KI. This was also attributed to the formation of smaller AgI particles and crystal defects. Highest electrical conductivity (3.8 x 10(-7) Ω(-1) cm(-1)) was obtained from the cellulose films (1.25 x 10(-11) Ω(-1) cm(-1)) treated with the aqueous solutions of 1.0 M I2/KI and 1.0 M AgNO3.

Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we functionalized BC hydrogel with polydopamine (PDA) without toxic crosslinkers and used it in skin tissue engineering. The BC nanofibers in the hydrogel had a thickness of 77.8 ± 20.3 nm, and they could be used to produce hydrophilic, adhesive, and cytocompatible composite biomaterials for skin tissue engineering applications using PDA. Characterization techniques, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, were performed to investigate the formation of polydopamine on the BC nanofibers. The XRD peaks for BC occur at 2θ = 14.65°, 16.69°, and 22.39°, which correspond to the planes of (100), (010), and (110) of cellulose type Iα. Raman spectroscopy confirmed the formation of PDA, as indicated by the presence of bands corresponding to the vibration of aromatic rings and aliphatic C–C and C–O stretching at 1336 and 1567 cm−1, respectively. FTIR confirmed the presence of peaks corresponding to PDA and BC in the BC/PDA hydrogel scaffolds at 3673, 3348, 2900, and 1052 cm−1, indicating the successful interaction of PDA with BC nanofibers, which was further corroborated by the SEM images. The tensile strength, swelling ratio, degradation, and surface wettability characteristics of the composite BC biomaterials were also investigated. The BC/PDA hydrogels with PDA-functionalized BC nanofibers demonstrated excellent tensile strength and water-wetting ability while maintaining the stability of the BC fibers. The enhanced cytocompatibility of the BC/PDA hydrogels was studied using the PrestoBlue assay. Culturing murine NIH/3T3 fibroblasts on BC/PDA hydrogels showed higher metabolic activity and enhanced proliferation. Additionally, it improved cell viability when using BC/PDA hydrogels. Thus, these BC/PDA composite biomaterials can be used as biocompatible natural alternatives to synthetic substitutes for skin tissue engineering and wound-dressing applications. [ABSTRACT FROM AUTHOR]

The development of waterborne polyurethane (WPU) has been stimulated as an alternative to solvent-based polyurethanes due to low-VOC alternatives and reduced exposure to solvents. However, their relatively low mechanical performance and degradation have presented challenges in their wide application. Here, we developed environmentally-friendly bio polyol-based WPU nanocomposite dispersions and films, and presented the optimal process conditions for their manufacture. Additionally, the condition was established without using harmful catalysts or ethyl methyl ketone (MEK) during the polymerization. Moreover, regenerated cellulose nanoparticles (RCNs) were employed as natural chain-extenders in order to improve the biodegradability and mechanical performances of the nanocomposite films. The RCNs have a lower crystallinity compared to cellulose nanocrystals (CNCs), allowing them to possess high toughness without interfering with the elastomeric properties of polyurethane. The prepared CWPU/RCNs nanocomposite films exhibited high toughness of 58.8 ± 3 kgf∙mm and elongation at break of 240 ± 20%. In addition, depending on the molar ratio of NCO/OH, the polyurethane particle size is variously controlled from 70 to 230 nm, enabling to fabricate their dispersions with various transmittances. We believe that our findings not only open a meaningful path toward green elastomers with biodegradability but provides the design concept for bio-elastomers in order to develop industrial elastomers with mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

The sharp increase in the use of cellulose seems to be in increasing demand in wood; much more research related to sustainable or alternative materials is necessary as a lot of the arable land and natural resources use is unsustainable. In accordance, attention has focused on bacterial cellulose as a new functional material. It possesses a three-dimensional, gelatinous structure consisting of cellulose with mechanical and thermal properties. Moreover, while a plant-originated cellulose is composed of cellulose, hemi-cellulose, and lignin, bacterial cellulose attributable to the composition of a pure cellulose nanofiber mesh spun is not necessary in the elimination of other components. Moreover, due to its hydrophilic nature caused by binding water, consequently being a hydrogel as well as biocompatibility, it has only not only used in medical fields including artificial skin, cartilage, vessel, and wound dressing, but also in delivery; some products have even been commercialized. In addition, it is widely used in various technologies including food, paper, textile, electronic and electrical applications, and is being considered as a highly versatile green material with tremendous potential. However, many efforts have been conducted for the evolution of novel and sophisticated materials with environmental affinity, which accompany the empowerment and enhancement of specific properties. In this review article, we summarized only industry and research status regarding BC and contemplated its potential in the use of BC. [ABSTRACT FROM AUTHOR]

Regarding the porous structure, coagulated cellulose may not provide sufficient voids for cell proliferation, resulting in tissue growth. For this reason, it was blended with poly(m-phenylene isophthalamide) (PMIA), which could produce a porous structure in the resulting construct. The aim of this study was to confirm the potential of a novel cellulose/PMIA porous film as a tissue-engineered bioconstruct for impaired skin. The films were fabricated by a coagulation process added with a peel-off method, and the structural, mechanical properties were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and capillary flow porometry. CRL-2310 human keratinocytes were used to determine the biocompatibility of the prepared films. The attachment and proliferation of cells were investigated by scanning electron microscopy, DAPI staining, and a cell viability assay. The results show that cellulose/PMIA porous films have potential use as wound matrices for skin tissue genesis. [ABSTRACT FROM AUTHOR]

In this study, a non-cytotoxic and pH-sensitive poly(acrylamidoglycolic acid) based nanocomposite (PAGA-NC) hydrogels reinforced with cellulose nanocrystals (CNCs) was synthesized using redox free radical polymerization. The successful formation and crystalline behaviour of PAGA-NC hydrogels was verified by fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses. The results showed that morphological, rheological and mechanical properties of the PAGA-NC hydrogels were strongly influenced by the CNCs content. Moreover, swelling properties were investigated, and the results suggested that they behaved as pH sensitive manner. The in vitro MTT assay showed that the PAGA-NC hydrogels are cytocompatibile to NIH-3T3 fibroblast cells. In addition, diclofenac sodium (DCF) model drug was successfully encapsulated into these PAGA-NC hydrogels via equilibrium swelling method. The in vitro release of DCF from PAGA-NC hydrogels was retained at pH 1.2 and maximum release was observed at 7.4, revealing as potential candidates for controlled release carriers for oral drug delivery applications. [ABSTRACT FROM AUTHOR]