Fabrication of bacterial cellulose-collagen composite scaffolds and their osteogenic effect on human mesenchymal stem cells

Spectroscopic investigation, dielectric and antimicrobial properties of chitin-cellulose@ZnO/CuO conductive nanocomposites

In this research, we fabricated a functional conductive nanocomposite with valuable properties through a chitin (CH) and cellulose (CE) polymerization process, incorporating ZnO/(0.1, 0.2, 0.3 mol.%) CuO bioactive nanoparticles. These bioactive nanoparticles, synthesized through sol-gel and polymerization interactions, greatly enhanced the structural, dielectric, and antimicrobial characteristics of CH-CE@ZnO/CuO conductive nanocomposites. The morphological analysis revealed that these nanoparticles, with diameters ranging from 11-25 nm, formed covalent bonds with the membrane matrix, bolstering the conductive nanocomposites ' structural integrity and dielectric performance. The dielectric properties of the conductive nanocomposites were significantly enhanced by the even distribution of ZnO/CuO nanoparticles within the CH-CE composite. Additionally, antimicrobial assessments demonstrated that the CH-CE@ZnO/CuO conductive nanocomposites displayed significant antibacterial properties against the Escherichia coli and Staphylococcus aureus, showcasing their potential as active packaging materials for electronic, biosensors, and sustainable applications.

Caenorhabditis elegans endorse bacterial nanocellulose fibers as functional dietary Fiber reducing lipid markers

Bacterial nanocellulose (BNC) is a promising dietary fiber with potential as a functional food additive. We evaluated BNC fibers (BNCf) in the Caenorhabditis elegans model to obtain insight into the BNCf's biointeraction with its gastrointestinal tract while reducing the variables of higher complex animals. BNCf were uptaken and excreted by worms without crossing the intestinal barrier, confirming its biosafety regarding survival rate, reproduction, and aging for concentrations up to 34 μg/ml BNCf. However, a slight decrease in the worms' length was detected. A possible nutrient shortage or stress produced by BNCf was discarded by measuring stress and chemotactic response pathways. Besides, we detected a lipid-lowering effect of BNCf in N2 C. elegans in normal and high-caloric diets. Oxidative damage was computed in N2 worms and Rac1/ced-10 mutants. The GTPase Rac1 is involved in neurological diseases, where its dysregulation enhances ROS production and neuronal damage. BNCf reduced the lipid oxidative markers produced by ROS species in this worm strain. Finally, we detected that BNCf activated the genetic expression of the immunological response and lipid catabolic process. These results strengthen the use of BNCf as a functional dietary fiber and encourage the potential treatment of neurological disease by modulating diet.

Nanocellulose-Based Hybrid Scaffolds for Skin and Bone Tissue Engineering: A 10-Year Overview

Cellulose, the most abundant polymer on Earth, has been widely utilized in its nanoform due to its excellent properties, finding applications across various scientific fields. As the demand for nanocellulose continues to rise and its ease of use becomes apparent, there has been a significant increase in research publications centered on this biomaterial. Nanocellulose, in its different forms, has shown tremendous promise as a tissue engineered scaffold for regeneration and repair. Particularly, nanocellulose-based composites and scaffolds have emerged as highly demanding materials for both soft and hard tissue engineering. Medical practitioners have traditionally relied on collagen and its analogue, gelatin, for treating tissue damage. However, the limited mechanical strength of these biopolymers restricts their direct use in various applications. This issue can be overcome by making hybrids of these biopolymers with nanocellulose. This review presents a comprehensive analysis of the recent and most relevant publications focusing on hybrid composites of collagen and gelatin with a specific emphasis on their combination with nanocellulose. While bone and skin tissue engineering represents two areas where a majority of researchers are concentrating their efforts, this review highlights the use of nanocellulose-based hybrids in these contexts.

Probiotic cultivated meat: bacterial-based scaffolds and products to improve cultivated meat

Cultivated meat is emerging to replace traditional livestock industries, which have ecological costs, including land and water overuse and considerable carbon emissions. During cultivated meat production, mammalian cells can increase their numbers dramatically through self-renewal/proliferation and transform into mature cells, such as muscle or fat cells, through maturation/differentiation. Here, we address opportunities for introducing probiotic bacteria into the cultivated meat industry, including using them to produce renewable antimicrobials and scaffolding materials. We also offer solutions to challenges, including the growth of bacteria and mammalian cells, the effect of probiotic bacteria on production costs, and the effect of bacteria and their products on texture and taste. Our summary provides a promising framework for applying microbial composites in the cultivated meat industry.

Composite of bacterial cellulose and gelatin: A versatile biocompatible scaffold for tissue engineering

Synthesis of 0.4 ± 0.03 g/L per day of pure and porous bacterial cellulose (BC) scaffolds (scaffBC) and BC scaffolds modified with gelatin (scaffBC/Gel) was carried out using the Medusomyces gisevii Sa-28 bacterial strain. FT-IR spectroscopy and X-ray diffraction analysis showed that the scaffolds largely consist of crystalline cellulose I (Iα, Iß). Heating of BC with gelatin to 60 °C with subsequent lyophilization led to its modification by adsorption and binding of low-molecular fractions of gelatin and the formation of small pores between the fibers, which increased the biocompatibility and solubility of BC. The solubility of scaffBC and scaffBC/Gel was 20.8 % and 44.4 %, respectively, which enhances degradation in vivo. Light microscopy, scanning electron microscopy, and microcomputed tomography showed a uniform distribution of pores with a diameter of 100-500 μm. The chicken chorioallantoic membrane (CAM) model and subcutaneous implantation in rats confirmed low immunogenicity and intense formation of collagen fibers in both scaffolds and active germination of new blood vessels in scaffBC and scaffBC/Gel. The proliferative cellular activity of fibroblasts confirmed the safety of scaffolds. Taken together, the results obtained show that scaffBC/Gel can be used for the engineering of hard and soft tissues, which opens opportunities for further research.

Applications of Bacterial Cellulose-Based Composite Materials in Hard Tissue Regenerative Medicine

BACKGROUND

Cartilage, bone, and teeth, as the three primary hard tissues in the human body, have a significant application value in maintaining physical and mental health. Since the development of bacterial cellulose-based composite materials with excellent biomechanical strength and good biocompatibility, bacterial cellulose-based composites have been widely studied in hard tissue regenerative medicine. This paper provides an overview of the advantages of bacterial cellulose-based for hard tissue regeneration and reviews the recent progress in the preparation and research of bacterial cellulose-based composites in maxillofacial cartilage, dentistry, and bone.

METHOD

A systematic review was performed by searching the PubMed and Web of Science databases using selected keywords and Medical Subject Headings search terms.

RESULTS

Ideal hard tissue regenerative medicine materials should be biocompatible, biodegradable, non-toxic, easy to use, and not burdensome to the human body; In addition, they should have good plasticity and processability and can be prepared into materials of different shapes; In addition, it should have good biological activity, promoting cell proliferation and regeneration. Bacterial cellulose materials have corresponding advantages and disadvantages due to their inherent properties. However, after being combined with other materials (natural/ synthetic materials) to form composite materials, they basically meet the requirements of hard tissue regenerative medicine materials. We believe that it is worth being widely promoted in clinical applications in the future.

CONCLUSION

Bacterial cellulose-based composites hold great promise for clinical applications in hard tissue engineering. However, there are still several challenges that need to be addressed. Further research is needed to incorporate multiple disciplines and advance biological tissue engineering techniques. By enhancing the adhesion of materials to osteoblasts, providing cell stress stimulation through materials, and introducing controlled release systems into matrix materials, the practical application of bacterial cellulose-based composites in clinical settings will become more feasible in the near future.

Cell-Laden 3D Hydrogels of Type I Collagen Incorporating Bacterial Nanocellulose Fibers

There is a growing interest in developing natural hydrogel-based scaffolds to culture cells in a three-dimensional (3D) millieu that better mimics the in vivo cells' microenvironment. A promising approach is to use hydrogels from animal tissues, such as decellularized extracellular matrices; however, they usually exhibit suboptimal mechanical properties compared to native tissue and their composition with hundreds of different protein complicates to elucidate which stimulus triggers cell's responses. As simpler scaffolds, type I collagen hydrogels are used to study cell behavior in mechanobiology even though they are also softer than native tissues. In this work, type I collagen is mixed with bacterial nanocellulose fibers (BCf) to develop reinforced scaffolds with mechanical properties suitable for 3D cell culture. BCf were produced from blended pellicles biosynthesized from Komagataeibacter xylinus. Then, BCf were mixed with concentrated collagen from rat-tail tendons to form composite hydrogels. Confocal laser scanning microscopy and scanning electron microscopy images confirmed the homogeneous macro- and microdistribution of both natural polymers. Porosity analysis confirmed that BCf do not disrupt the scaffold structure. Tensile strength and rheology measurements demonstrated the reinforcement action of BCf (43% increased stiffness) compared to the collagen hydrogel while maintaining the same viscoelastic response. Additionally, this reinforcement of collagen hydrogels with BCf offers the possibility to mix cells before gelation and then proceed to the culture of the 3D cell scaffolds. We obtained scaffolds with human bone marrow-derived mesenchymal stromal cells or human fibroblasts within the composite hydrogels, allowing a homogeneous 3D viable culture for at least 7 days. A smaller surface shrinkage in the reinforced hydrogels compared to type I collagen hydrogels confirmed the strengthening of the composite hydrogels. These collagen hydrogels reinforced with BCf might emerge as a promising platform for 3D in vitro organ modeling, tissue-engineering applications, and suitable to conduct fundamental mechanobiology studies.

Opportunities for bacterial nanocellulose in biomedical applications: Review on biosynthesis, modification and challenges

Bacterial nanocellulose (BNC) is a natural polysaccharide produced as extracellular material by bacterial strains and has favorable intrinsic properties for primary use in biomedical applications. In this review, an update on state-of-the art and challenges in BNC production, surface modification and biomedical application is given. Recent insights in biosynthesis allowed for better understanding of governing parameters improving production efficiency. In particular, introduction of different carbon/nitrogen sources from alternative feedstock and industrial upscaling of various production methods is challenging. It is important to have control on the morphology, porosity and forms of BNC depending on biosynthesis conditions, depending on selection of bacterial strains, reactor design, additives and culture conditions. The BNC is intrinsically characterized by high water absorption capacity, good thermal and mechanical stability, biocompatibility and biodegradability to certain extent. However, additional chemical and/or physical surface modifications are required to improve cell compatibility, protein interaction and antimicrobial properties. The novel trends in synthesis include the in-situ culturing of hybrid BNC nanocomposites in combination with organic material, inorganic material or extracellular components. In parallel with toxicity studies, the applications of BNC in wound care, tissue engineering, medical implants, drug delivery systems or carriers for bioactive compounds, and platforms for biosensors are highlighted.

Cellulose-based composite scaffolds for bone tissue engineering and localized drug delivery

Natural bone constitutes a complex and organized structure of organic and inorganic components with limited ability to regenerate and restore injured tissues, especially in large bone defects. To improve the reconstruction of the damaged bones, tissue engineering has been introduced as a promising alternative approach to the conventional therapeutic methods including surgical interventions using allograft and autograft implants. Bioengineered composite scaffolds consisting of multifunctional biomaterials in combination with the cells and bioactive therapeutic agents have great promise for bone repair and regeneration. Cellulose and its derivatives are renewable and biodegradable natural polymers that have shown promising potential in bone tissue engineering applications. Cellulose-based scaffolds possess numerous advantages attributed to their excellent properties of non-toxicity, biocompatibility, biodegradability, availability through renewable resources, and the low cost of preparation and processing. Furthermore, cellulose and its derivatives have been extensively used for delivering growth factors and antibiotics directly to the site of the impaired bone tissue to promote tissue repair. This review focuses on the various classifications of cellulose-based composite scaffolds utilized in localized bone drug delivery systems and bone regeneration, including cellulose-organic composites, cellulose-inorganic composites, cellulose-organic/inorganic composites. We will also highlight the physicochemical, mechanical, and biological properties of the different cellulose-based scaffolds for bone tissue engineering applications.

Molecular and thermodynamic insights into interfacial interactions between collagen and cellulose investigated by molecular dynamics simulation and umbrella sampling

Cellulose/collagen composites have been widely used in biomedicine and tissue engineering. Interfacial interactions are crucial in determining the final properties of cellulose/collagen composite. Molecular dynamics simulations were carried out to gain insights into the interactions between cellulose and collagen. It has been found that the structure of collagen remained intact during adsorption. The results derived from umbrella sampling showed that (110) and ([Formula: see text]) faces exhibited the strongest affinity with collagen (100) face came the second and (010) the last, which could be attributed to the surface roughness and hydrogen-bonding linkers involved water molecules. Cellulose planes with flat surfaces and the capability to form hydrogen-bonding linkers produce stronger affinity with collagen. The occupancy of hydrogen bonds formed between cellulose and collagen was low and not significantly contributive to the binding affinity. These findings provided insights into the interactions between cellulose and collagen at the molecular level, which may guide the design and fabrication of cellulose/collagen composites.

Pineapple Agro-Industrial Biomass to Produce Biomedical Applications in a Circular Economy Context in Costa Rica

Pineapple is a highly demanded fruit in international markets due to its unique appearance and flavor, high fiber content, vitamins, folic acid, and minerals. It makes pineapple production and processing a significant source of income for producing countries, such as Costa Rica. This review collects bibliographic information dating back to the beginnings of pineapple production in Costa Rica to the state of the market today. It details the impacts of its production chain and proposes a biorefinery as a solution to environmental problems. Besides the potentiality of new sustainable markets to contribute to the post-COVID-19 economy in Costa Rica is highlighted. The general characteristics of pineapple by-products -cellulose, hemicellulose, lignin, and other high-value products like bromelain y saponin- are described, as well as the primary processes for their ex-traction via biorefinery and main applications in the medical field. Finally, a brief description of the main works in the literature involving modeling and simulation studies of pineapple by-products properties is included.

Preparation of an Active Dressing by In Situ Biosynthesis of a Bacterial Cellulose–Graphene Oxide Composite

This paper presents a simple method of obtaining a bacterial cellulose (BC) composite with the addition of graphene oxide (GO) using an in situ method and studies the influence of GO nanoparticles on the structure and properties of the obtained membranes. Microorganisms obtained from Golden Delicious apple vinegar were used to obtain the BC. During the biosynthesis, GO was introduced in the amounts of 3.7, 5.4 and 7.1% w/w. The resulting BC/GO composite was characterized by high water content (~400%), a thickness of about 1.1 mm (in wet form) and a cellulose nanofiber diameter of ~100 nm. The possibility of using the resulting composite membranes as potential active dressings with the sustained-release analgesic medicine—paracetamol—was investigated. The BC/GO composite membranes were characterized by a medicine sorption of 60 mg/g of BC, a slow desorption time, a constant medicine concentration over time and an 80% paracetamol release rate after 24 h. The morphology of membrane surfaces and cross-sections were examined by means of scanning electron microscopy (SEM). Infrared spectroscopy (FTIR), X-ray structure studies (WAXS) as well as thermal analysis (TGA) demonstrated the presence of GO in the BC matrix and interactions between the matrix and the additive.

Green Polymer Nanocomposites for Skin Tissue Engineering

Fabrication of an appropriate skin scaffold needs to meet several standards related to the mechanical and biological properties. Fully natural/green scaffolds with acceptable biodegradability, biocompatibility, and physiological properties quite often suffer from poor mechanical properties. Therefore, for appropriate skin tissue engineering and to mimic the real functions, we need to use synthetic polymers and/or additives as complements to green polymers. Green nanocomposites (either nanoscale natural macromolecules or biopolymers containing nanoparticles) are a class of scaffolds with acceptable biomedical properties window (drug delivery and cardiac, nerve, bone, cartilage as well as skin tissue engineering), enabling one to achieve the required level of skin regeneration and wound healing. In this review, we have collected, summarized, screened, analyzed, and interpreted the properties of green nanocomposites used in skin tissue engineering and wound dressing. We particularly emphasize the mechanical and biological properties that skin cells need to meet when seeded on the scaffold. In this regard, the latest state of the art studies directed at fabrication of skin tissue and bionanocomposites as well as their mechanistic features are discussed, whereas some unspoken complexities and challenges for future developments are highlighted.

The Effect of Layering Structures on Mechanical and Thermal Properties of Hybrid Bacterial Cellulose/Kevlar Reinforced Epoxy Composites

The effect of layering structures on mechanical and thermal hybrid bacterial cellulose (BC) sheet/Kevlar reinforced epoxy composites was investigated. The BC sheet was extracted from Nata de Coco and used as green reinforcement material hybrid with Kevlar reinforced epoxy composites. The BC/Kevlar reinforced epoxy composite was fabricated by using hand lay-up technique equipped with vacuum bagging system and the BC sheets and Kevlar layers were laminated into different layered structures. The performance of the hybrid BC/Kevlar reinforced epoxy composites was characterized through tensile test and low velocity impact according to ASTM D3039 and ASTM D7136, respectively. The thermal performance of the hybrid composites was characterized by using dynamic mechanical analysis (DMA) test. Tensile test on BC sheet composites with Kevlar and epoxy demonstrated that the addition of BC sheet in BC/Kevlar could not withstand the tensor stress by reducing the tensile stress and Young's modulus. The one layer of Kevlar which was replaced with three to six BC sheets had increased the ability to absorb impact force. The storage modulus (E′) and Tan δ were significantly dependent on the number of BC sheets and its layering structure. The highest value of E′ was observed when BC sheets were arranged alternately with the Kevlar layers. Different damage mechanisms associated with the number of BC sheets and its layered-structure suggested that the BC sheet was functioning as an impact energy absorber as well as strengthening fibers. This study will upsurge interest in BC reinforced composites and the development of new ideas in automotive, marine and bullet applications.

Bacterial cellulose as a potential biopolymer in biomedical applications: a state-of-the-art review

Throughout history, natural biomaterials have benefited society. Nevertheless, in recent years, tailoring natural materials for diverse biomedical applications accompanied with sustainability has become the focus. With the progress in the field of materials science, novel approaches for the production, processing, and functionalization of biomaterials to obtain specific architectures have become achievable. This review highlights an immensely adaptable natural biomaterial, bacterial cellulose (BC). BC is an emerging sustainable biopolymer with immense potential in the biomedical field due to its unique physical properties such as flexibility, high porosity, good water holding capacity, and small size; chemical properties such as high crystallinity, foldability, high purity, high polymerization degree, and easy modification; and biological characteristics such as biodegradability, biocompatibility, excellent biological affinity, and non-biotoxicity. The structure of BC consists of glucose monomer units polymerized via cellulose synthase in β-1-4 glucan chains, creating BC nano fibrillar bundles with a uniaxial orientation. BC-based composites have been extensively investigated for diverse biomedical applications due to their similarity to the extracellular matrix structure. The recent progress in nanotechnology allows the further modification of BC, producing novel BC-based biomaterials for various applications. In this review, we strengthen the existing knowledge on the production of BC and BC composites and their unique properties, and highlight the most recent advances, focusing mainly on the delivery of active pharmaceutical compounds, tissue engineering, and wound healing. Further, we endeavor to present the challenges and prospects for BC-associated composites for their application in the biomedical field.

Bacterial Cellulose-A Remarkable Polymer as a Source for Biomaterials Tailoring

Nowadays, the development of new eco-friendly and biocompatible materials using ‘green’ technologies represents a significant challenge for the biomedical and pharmaceutical fields to reduce the destructive actions of scientific research on the human body and the environment. Thus, bacterial cellulose (BC) has a central place among these novel tailored biomaterials. BC is a non-pathogenic bacteria-produced polysaccharide with a 3D nanofibrous structure, chemically identical to plant cellulose, but exhibiting greater purity and crystallinity. Bacterial cellulose possesses excellent physicochemical and mechanical properties, adequate capacity to absorb a large quantity of water, non-toxicity, chemical inertness, biocompatibility, biodegradability, proper capacity to form films and to stabilize emulsions, high porosity, and a large surface area. Due to its suitable characteristics, this ecological material can combine with multiple polymers and diverse bioactive agents to develop new materials and composites. Bacterial cellulose alone, and with its mixtures, exhibits numerous applications, including in the food and electronic industries and in the biotechnological and biomedical areas (such as in wound dressing, tissue engineering, dental implants, drug delivery systems, and cell culture). This review presents an overview of the main properties and uses of bacterial cellulose and the latest promising future applications, such as in biological diagnosis, biosensors, personalized regenerative medicine, and nerve and ocular tissue engineering.

Fibrous Polymer-Based Composites Obtained by Electrospinning for Bone Tissue Engineering

Currently, the significantly developing fields of tissue engineering related to the fabrication of polymer-based materials that possess microenvironments suitable to provide cell attachment and promote cell differentiation and proliferation involve various materials and approaches. Biomimicking approach in tissue engineering is aimed at the development of a highly biocompatible and bioactive material that would most accurately imitate the structural features of the native extracellular matrix consisting of specially arranged fibrous constructions. For this reason, the present research is devoted to the discussion of promising fibrous materials for bone tissue regeneration obtained by electrospinning techniques. In this brief review, we focus on the recently presented natural and synthetic polymers, as well as their combinations with each other and with bioactive inorganic incorporations in order to form composite electrospun scaffolds. The application of several electrospinning techniques in relation to a number of polymers is touched upon. Additionally, the efficiency of nanofibrous composite materials intended for use in bone tissue engineering is discussed based on biological activity and physiochemical characteristics.

Bacterial cellulose-based composites for biomedical and cosmetic applications: Research progress and existing products

Bacterial cellulose (BC) is a promising unique material for various biomedical and cosmetic applications due to its morphology, mechanical strength, high purity, high water uptake, non-toxicity, chemical controllability, and biocompatibility. Today, extensive investigation is into the manufacturing of BC-based composites with other components such as nanoparticles, synthetic polymers, natural polymers, carbon materials, and biomolecules, which will allow the development of a wide range of biomedical and cosmetic products. Moreover, the addition of different reinforcement substances into BC and the organized arrangement of BC nano-fibers have proven a promising improvement in their properties for biomedical applications. This review paper highlights the progress in synthesizing BC-based composites and their applications in biomedical fields, such as wound healing, drug delivery, tissue engineering, and cancer treatment. It emphasizes high-performance BC-based materials and cosmetic applications. Furthermore, it presents challenges yet to be defeated and future possibilities for BC-based composites for biomedical and cosmetic applications.

Bacterial cellulose and its potential for biomedical applications

Bacterial cellulose (BC) is an important polysaccharide synthesized by some bacterial species under specific culture conditions, which presents several remarkable features such as microporosity, high water holding capacity, good mechanical properties and good biocompatibility, making it a potential biomaterial for medical applications. Since its discovery, BC has been used for wound dressing, drug delivery, artificial blood vessels, bone tissue engineering, and so forth. Additionally, BC can be simply manipulated to form its derivatives or composites with enhanced physicochemical and functional properties. Several polymers, carbon-based nanomaterials, and metal nanoparticles (NPs) have been introduced into BC by ex situ and in situ methods to design hybrid materials with enhanced functional properties. This review provides comprehensive knowledge and highlights recent advances in BC production strategies, its structural features, various in situ and ex situ modification techniques, and its potential for biomedical applications.

Efficacy of Bacterial Nanocellulose in Hard Tissue Regeneration: A Review

Bacterial nanocellulose (BNC, as exopolysaccharide) synthesized by some specific bacteria strains is a fascinating biopolymer composed of the three-dimensional pure cellulosic nanofibrous matrix without containing lignin, hemicellulose, pectin, and other impurities as in plant-based cellulose. Due to its excellent biocompatibility (in vitro and in vivo), high water-holding capacity, flexibility, high mechanical properties, and a large number of hydroxyl groups that are most similar characteristics of native tissues, BNC has shown great potential in tissue engineering applications. This review focuses on and discusses the efficacy of BNC- or BNC-based biomaterials for hard tissue regeneration. In this review, we provide brief information on the key aspects of synthesis and properties of BNC, including solubility, biodegradability, thermal stability, antimicrobial ability, toxicity, and cellular response. Further, modification approaches are discussed briefly to improve the properties of BNC or BNC-based structures. In addition, various biomaterials by using BNC (as sacrificial template or matrix) or BNC in conjugation with polymers and/or fillers are reviewed and discussed for dental and bone tissue engineering applications. Moreover, the conclusion with perspective for future research directions of using BNC for hard tissue regeneration is briefly discussed.

Advanced Functional Materials Based on Nanocellulose for Pharmaceutical/Medical Applications

Nanocelluloses (NCs), with their remarkable characteristics, have proven to be one of the most promising "green" materials of our times and have received special attention from researchers in nanomaterials. A diversity of new functional materials with a wide range of biomedical applications has been designed based on the most desirable properties of NCs, such as biocompatibility, biodegradability, and their special physicochemical properties. In this context and under the pressure of rapid development of this field, it is imperative to synthesize the successes and the new requirements in a comprehensive review. The first part of this work provides a brief review of the characteristics of the NCs (cellulose nanocrystals-CNC, cellulose nanofibrils-CNF, and bacterial nanocellulose-BNC), as well as of the main functional materials based on NCs (hydrogels, nanogels, and nanocomposites). The second part presents an extensive review of research over the past five years on promising pharmaceutical and medical applications of nanocellulose-based materials, which have been discussed in three important areas: drug-delivery systems, materials for wound-healing applications, as well as tissue engineering. Finally, an in-depth assessment of the in vitro and in vivo cytotoxicity of NCs-based materials, as well as the challenges related to their biodegradability, is performed.

Transcutaneous Drug Delivery Systems Based on Collagen/Polyurethane Composites Reinforced with Cellulose

Designing composites based on natural polymers has attracted attention for more than a decade due to the possibility to manufacture medical devices which are biocompatible with the human body. Herein, we present some biomaterials made up of collagen, polyurethane, and cellulose doped with lignin and lignin-metal complex, which served as transcutaneous drug delivery systems. Compared with base material, the compressive strength and the elastic modulus of biocomposites comprising lignin or lignin-metal complex were significantly enhanced; thus, the compressive strength increased from 61.37 to 186.5 kPa, while the elastic modulus increased from 0.828 to 1.928 MPa. The release of ketokonazole from the polymer matrix follows a Korsmeyer–Peppas type kinetics with a Fickian diffusion. All materials tested were shown to be active against pathogenic microorganisms. The mucoadhesiveness, bioadhesiveness, mechanical resistance, release kinetic, and antimicrobial activity make these biocomposites to be candidates as potential systems for controlled drug release.

Nanocellulose-Reinforced Hydroxyapatite Nanobelt Membrane as a Stem Cell Multi-Lineage Differentiation Platform for Biomimetic Construction of Bioactive 3D Osteoid Tissue In Vitro

Severe bone defects, especially accompanied by vascular and peripheral nerve injuries, remain a massive challenge. Most studies related to bone tissue engineering have focused on osteogenic differentiation of mesenchymal stem cells (MSCs), and ignored the formation of blood vessels and nerves in the newly generated bone owing to the lack of proper materials and methodology for tuning stem cells differentiated into osteogenic, neuronal, and endothelial cells (ECs) in the same scaffold system. Herein, a nanocellulose-reinforced hybrid membrane with good mechanical properties and control over biodegradation by assembling ultralong hydroxyapatite nanobelts in a bacterial nanocellulose hydrogel is designed and synthesized. Osteogenic, neuronal cells are successfully differentiated on this hybrid membrane. Based on the multi-lineage differentiation property of the membrane, a bioactive 3D osteoid tissue (osteogenic, neural, and ECs) is mimetically constructed in vitro using layer-by-layer culture and integration. The bone regeneration ability of the as-prepared bioactive osteoid tissue is assessed in vivo via heterotopic osteogenesis experiments for eight weeks. The rapid new bone growth and formation of blood capillaries and nerve fibers prove that the hybrid membrane can be universally applied as a stem cell multi-lineage differentiation platform, which has significant applications in bone tissue engineering.

A Comparative Review of Natural and Synthetic Biopolymer Composite Scaffolds

Tissue engineering (TE) and regenerative medicine integrate information and technology from various fields to restore/replace tissues and damaged organs for medical treatments. To achieve this, scaffolds act as delivery vectors or as cellular systems for drugs and cells; thereby, cellular material is able to colonize host cells sufficiently to meet up the requirements of regeneration and repair. This process is multi-stage and requires the development of various components to create the desired neo-tissue or organ. In several current TE strategies, biomaterials are essential components. While several polymers are established for their use as biomaterials, careful consideration of the cellular environment and interactions needed is required in selecting a polymer for a given application. Depending on this, scaffold materials can be of natural or synthetic origin, degradable or nondegradable. In this review, an overview of various natural and synthetic polymers and their possible composite scaffolds with their physicochemical properties including biocompatibility, biodegradability, morphology, mechanical strength, pore size, and porosity are discussed. The scaffolds fabrication techniques and a few commercially available biopolymers are also tabulated.

Limbal Stem Cells on Bacterial Nanocellulose Carriers for Ocular Surface Regeneration

Limbal stem cells (LSCs) are already used in cell-based treatments for ocular surface disorders. Clinical translation of LSCs-based therapies critically depends on the successful delivery, survival, and retention of these therapeutic cells to the desired region. Such a major bottleneck could be overcome by using an appropriate carrier to provide anchoring sites and structural support to LSC culture and transplantation. Bacterial nanocellulose (BNC) is an appealing, yet unexplored, candidate for this application because of its biocompatibility, animal-free origin and mechanical stability. Here, BNC as a vehicle for human embryonic stem cells-derived LSC (hESC-LSC) are investigated. To enhance cell-biomaterial interactions, a plasma activation followed by a Collagen IV and Laminin coating of the BNC substrates is implemented. This surface functionalization with human extracellular matrix proteins greatly improved the attachment and survival of hESC-LSC without compromising the flexible, robust and semi-transparent nature of the BNC. The surface characteristics of the BNC substrates are described and a preliminary ex vivo test in simulated transplantation scenarios is provided. Importantly, it is shown that hESC-LSC retain their self-renewal and stemness characteristics up to 21 days on BNC substrates. These results open the door for future research on hESC-LSC/BNC constructs to treat severe ocular surface pathologies.

Effects of chitosan-collagen dressing on wound healing in vitro and in vivo assays

The present study was designed to fabricate a new chitosan-collagen sponge (CCS) for potential wound dressing applications. CCS was fabricated by a 3.0% chitosan mixture with a 1.0% type I collagen (7:3(w/w)) through freeze-drying. Then the dressing was prepared to evaluate its properties through a series of tests. The new-made dressing demonstrated its safety toward NIH3T3 cells. Furthermore, the CCS showed the significant surround inhibition zone than empty controls inoculated by E. coli and S. aureus. Moreover, the moisture rates of CCS were increased more rapidly than the collagen and blank sponge groups. The results revealed that the CCS had the characteristics of nontoxicity, biocompatibility, good antibacterial activity, and water retention. We used a full-thickness excisional wound healing model to evaluate the in vivo efficacy of the new dressing. The results showed remarkable healing at 14th day post-operation compared with injuries treated with collagen only as a negative control in addition to chitosan only. Our results suggest that the chitosan-collagen wound dressing were identified as a new promising candidate for further wound application.

Sustained release of epigallocatechin-3-gallate from chitosan-based scaffolds to promote osteogenesis of mesenchymal stem cell

Epigallocatechin-3-gallate (EGCG) is a kind of flavonoids and has the ability to promote differentiation of mesenchymal stem cells (MSCs) into osteoblasts. However, the EGCG is easily metabolized by cells during cell culture, which reduces its bioavailability. Therefore, in this paper, EGCG-loaded chitosan nanoparticles (ECN) were fabricated and entrapped into chitosan/alginate (CS/Alg) scaffolds to form CS/Alg-ECN scaffolds for improving the bioavailability of EGCG. The human umbilical cord mesenchymal stem cells (HUMSCs) were cultured on CS/Alg-ECN scaffolds to induce osteogenic differentiation. The results indicated that the CS/Alg-ECN scaffolds continuously released EGCG for up to 16 days. Besides, these results suggested that CS/Alg-ECN scaffolds promoted osteoblast differentiation through activating Wnt/β-catenin signaling pathway. Collectively, this study demonstrated that the entrapment ECN into CS/Alg scaffolds was a promising strategy for promoting osteogenesis of MSCs.

Assessment of properties, applications and limitations of scaffolds based on cellulose and its derivatives for cartilage tissue engineering: A review

Cartilage is a connective tissue, which is made up of ~80% of water. It is alymphatic, aneural and avascular with only one type of cells present, chondrocytes. They constitute about 1-5% of the entire cartilage tissue. It has a very limited capacity for spontaneous repair. Articular cartilage defects are quite common due to trauma, injury or aging and these defects eventually lead to osteoarthritis, affecting the daily activities. Tissue engineering (TE) is a promising strategy for the regeneration of articular cartilage when compared to the existing invasive treatment strategies. Cellulose is the most abundant natural polymer and has desirable properties for the development of a scaffold, which can be used for the regeneration of cartilage. This review discusses about (i) the basic science behind cartilage TE and the study of cellulose properties that can be exploited for the construction of the engineered scaffold with desired properties for cartilage tissue regeneration, (ii) about the requirement of scaffolds properties, fabrication mechanisms and assessment of cellulose based scaffolds, (iii) details about the modification of cellulose surface by employing various chemical approaches for the production of cellulose derivatives with enhanced characteristics and (iv) limitations and future research prospects of cartilage TE.

Development of Bacterial Cellulose Biocomposites Combined with Starch and Collagen and Evaluation of Their Properties

One of the major benefits of biomedicine is the use of biocomposites as wound dressings to help improve the treatment of injuries. Therefore, the main objective of this study was to develop and characterize biocomposites based on bacterial cellulose (BC) with different concentrations of collagen and starch and characterize their thermal, morphological, mechanical, physical, and barrier properties. In total, nine samples were produced with fixed amounts of glycerol and BC and variations in the amount of collagen and starch. The water activity (0.400–0.480), water solubility (12.94–69.7%), moisture (10.75–20.60%), thickness (0.04–0.11 mm), water vapor permeability (5.59–14.06 × 10⁻⁸ g·mm/m²·h·Pa), grammage (8.91–39.58 g·cm⁻²), opacity (8.37–36.67 Abs 600 nm·mm⁻¹), elongation (4.81–169.54%), and tensile strength (0.99–16.32 MPa) were evaluated and defined. In addition, scanning electron microscopy showed that adding biopolymers in the cellulose matrix made the surface compact, which also influenced the visual appearance. Thus, the performance of the biocomposites was directly influenced by their composition. The performance of the different samples obtained resulted in them having different potentials for application considering the injury type. This provides a solution for the ineffectiveness of traditional dressings, which is one of the great problems of the biomedical sector.

Electrospun Nanofibers of Natural and Synthetic Polymers as Artificial Extracellular Matrix for Tissue Engineering

Many types of polymer nanofibers have been introduced as artificial extracellular matrices. Their controllable properties, such as wettability, surface charge, transparency, elasticity, porosity and surface to volume proportion, have attracted much attention. Moreover, functionalizing polymers with other bioactive components could enable the engineering of microenvironments to host cells for regenerative medical applications. In the current brief review, we focus on the most recently cited electrospun nanofibrous polymeric scaffolds and divide them into five main categories: natural polymer-natural polymer composite, natural polymer-synthetic polymer composite, synthetic polymer-synthetic polymer composite, crosslinked polymers and reinforced polymers with inorganic materials. Then, we focus on their physiochemical, biological and mechanical features and discussed the capability and efficiency of the nanofibrous scaffolds to function as the extracellular matrix to support cellular function.

Characterization of Bacterial Cellulose-Based Wound Dressing in Different Order Impregnation of Chitosan and Collagen

Bacterial cellulose (BC), chitosan (Chi), and collagen (Col) are known as biopolymers which have met some properties that are required as wound dressing. This study focused on investigating the fabrication of BC-based wound dressing with chitosan and collagen, since chitosan has red blood cells binding and anti-bacterial properties, while collagen can support cell and tissue growth for skin wounds. The BC-based wound dressing was prepared by impregnating BC fibers in the chitosan and/or collagen solution for 24 h. FTIR was used to confirm the intermolecular interaction of amine and hydroxyl group of chitosan and/or collagen in BC-based wound dressing. Furthermore, the XRD diffractogram of the wound dressing show broader peaks at 14.2°, 16.6°, and 22.4° due to the presence of chitosan and collagen molecules in BC fibers. These results were then supported by SEM images which confirmed that chitosan and collagen were well penetrated into BC fibers. TGA curves revealed that BC/Chi/Col has better thermal properties based on the Tmax compare to BC/Col/Chi. Feasibility of the mats to be applied as wound dressing was also supported by other tests, i.e., water content, porosity, and hemocompatibility, which indicates that the wound dressing is classified as nonhemolytic materials. However, BC/Col/Chi was considered a more potential wound dressing to be applied compared to BC/Chi/Col since it has larger pores and showed better antibacterial properties (larger zones of inhibition) against S. aureus and E. coli via disk diffusion tests.

3D Printed Polycaprolactone/Gelatin/Bacterial Cellulose/Hydroxyapatite Composite Scaffold for Bone Tissue Engineering

Three-dimensional (3D) printing application is a promising method for bone tissue engineering. For enhanced bone tissue regeneration, it is essential to have printable composite materials with appealing properties such as construct porous, mechanical strength, thermal properties, controlled degradation rates, and the presence of bioactive materials. In this study, polycaprolactone (PCL), gelatin (GEL), bacterial cellulose (BC), and different hydroxyapatite (HA) concentrations were used to fabricate a novel PCL/GEL/BC/HA composite scaffold using 3D printing method for bone tissue engineering applications. Pore structure, mechanical, thermal, and chemical analyses were evaluated. 3D scaffolds with an ideal pore size (~300 µm) for use in bone tissue engineering were generated. The addition of both bacterial cellulose (BC) and hydroxyapatite (HA) into PCL/GEL scaffold increased cell proliferation and attachment. PCL/GEL/BC/HA composite scaffolds provide a potential for bone tissue engineering applications.

Development and Performance of Bioactive Compounds-Loaded Cellulose/Collagen/Polyurethane Materials

Here we present a new biomaterial based on cellulose, collagen and polyurethane, obtained by dissolving in butyl imidazole chloride. This material served as a matrix for the incorporation of tannin and lipoic acid, as well as bioactive substances with antioxidant properties. The introduction of these bioactive principles into the base matrix led to an increase of the compressive strength in the range 105-139 kPa. An increase of 29.85% of the mucoadhesiveness of the film containing tannin, as compared to the reference, prolongs the bioavailability of the active substance; a fact also demonstrated by the controlled release studies. The presence of bioactive principles, as well as tannins and lipoic acid, gives biomaterials an antioxidant capacity on average 40%-50% higher compared to the base matrix. The results of the tests of the mechanical resistance, mucoadhesiveness, bioadhesiveness, water absorption and antioxidant capacity of active principles recommend these biomaterials for the manufacture of cosmetic masks or patches.

Bacterial Cellulose as a Versatile Platform for Research and Development of Biomedical Materials

The unique pool of features found in intracellular and extracellular bacterial biopolymers attracts a lot of research, with bacterial cellulose (BC) being one of the most versatile and common. BC is an exopolysaccharide consisting solely of cellulose, and the variation in the production process can vary its shape or even its composition when compounding is applied in situ. Together with ex situ modification pathways, including specialised polymers, particles or exclusively functional groups, BC provides a robust platform that yields complex multifunctional compounds that go far beyond ultra-high purity, intrinsic hydrophilicity, mechanical strength and biocompatibility to introduce bioactive, (pH, thermal, electro) responsive, conductive and ‘smart’ properties. This review summarises the research outcomes in BC-medical applications, focusing mainly on data from the past decade (i.e., 2010–2020), with special emphasis on BC nanocomposites as materials and devices applicable in medicine. The high purity and unique structural/mechanical features, in addition to its capacity to closely adhere to irregular skin surfaces, skin tolerance, and demonstrated efficacy in wound healing, all stand as valuable attributes advantageous in topical drug delivery. Numerous studies prove BC compatibility with various human cells, with modifications even improving cell affinity and viability. Even BC represents a physical barrier that can reduce the penetration of bacteria into the tissue, but in its native form does not exhibit antimicrobial properties, therefore carious modifications have been made or specific compounds added to confer antimicrobial or anti-inflammatory properties. Progress in the use of BC-compounds as wound dressings, vascular grafts, and scaffolds for the treatment of cartilage, bone and osteochondral defects, the role as a basement membrane in blood-brain barrier models and many more are discussed to particular extent, emphasising the need for BC compounding to meet specific requirements.