Bacterial Cellulose-Chitosan-Glycerol Biocomposite as Artificial Dura Mater Candidates for Head Trauma

Biomimetic and Nonbiomimetic Approaches in Dura Substitutes: The Influence of Mechanical Properties

The dura mater, the furthest and strongest layer of the meninges, is crucial for protecting the brain and spinal cord. Its biomechanical behavior is vital, as any alterations can compromise biological functions. In recent decades, interest in the dura mater has increased due to the need for hermetic closure of dural defects prompting the development of several substitutes. Collagen-based dural substitutes are common commercial options, but they lack the complex biological and structural elements of the native dura mater, impacting regeneration and potentially causing complications like wound/postoperative infection and cerebrospinal fluid (CSF) leakage. To face this issue, recent tissue engineering approaches focus on creating biomimetic dura mater substitutes. The objective of this review is to discuss whether mimicking the mechanical properties of native tissue or ensuring high biocompatibility and bioactivity is more critical in developing effective dural substitutes, or if both aspects should be systematically linked. After a brief description of the properties and architecture of the native cranial dura, we describe the advantages and limitations of biomimetic dura mater substitutes to better understand their relevance. In particular, we consider biomechanical properties' impact on dura repair's effectiveness. Finally, the obstacles and perspectives for developing the ideal dural substitute are explored.

Strength Enhancement of Regenerated Cellulose Fibers by Adjustment of Hydrogen Bond Distribution in Ionic Liquid

To improve the physical strength of regenerated cellulose fibers, cellulose dissolution was analyzed with a conductor-like screening model for real solvents in which 1-allyl-3-methylimidazolium chloride (AMIMCl) worked only as a hydrogen bond acceptor while dissolving the cellulose. This process could be promoted by the addition of urea, glycerol, and choline chloride. The dissolution and regeneration of cellulose was achieved through dry-jet and wet-spinning. The results demonstrated that the addition of hydrogen bond donors and acceptors either on their own or in combination can enhance the tensile strength, but their effects on the crystallinity of the regenerated fibers were quite limited. Compared with the regenerated fibers without any additives, the tensile strength was improved from 54.43 MPa to 139.62 MPa after introducing the choline chloride and glycerol, while related the crystallinity was only changed from 60.06% to 62.97%. By contrast, a more compact structure and fewer pores on the fiber surface were identified in samples with additives along with well-preserved cellulose frameworks. Besides, it should be noted that an optimization in the overall thermal stability was obtained in samples with additives. The significant effect of regenerated cellulose with the addition of glycerol was attributed to the reduction of cellulose damage by slowing down the dissolution and cross-linking in the cellulose viscose. The enhancement of the physical strength of regenerated cellulose fiber can be realized by the appropriate adjustment of the hydrogen bond distribution in the ionic liquid system with additives.

Nanofluid to Nanocomposite Film: Chitosan and Cellulose-Based Edible Packaging

Chitosan (CH)-based materials are compatible to form biocomposite film for food packaging applications. In order to enhance water resistance and mechanical properties, cellulose can be introduced to the chitosan-based film. In this work, we evaluate the morphology and water resistance of films prepared from chitosan and cellulose in their nanoscale form and study the phenomena underlying the film formation. Nanofluid properties are shown to be dependent on the particle form and drive the morphology of the prepared film. Film thickness and water resistance (in vapor or liquid phase) are clearly enhanced by the adjunction of nanocrystalline cellulose.

Applications of bacterial-synthesized cellulose in veterinary medicine – a review

Tissue engineering promotes tissue regeneration through biomaterials that have excellent properties and have the potential to replace tissues. Many studies show that bacterial cellulose (BC) might ensure tissue regeneration and substitution, being used for the bioengineering of hard, cartilaginous and soft tissues. Bacterial cellulose is extensively used as wound dressing material and results show that BC is a promising tissue scaffold (bone, cardiovascular, urinary tissue). It can be combined with polymeric and non-polymeric compounds to acquire antimicrobial, cell-adhesion and proliferation properties. To ensure proper tissue regeneration, the material has to be: biocompatible, with minimum tissue reaction and biodegradability; bio-absorbable, to promote tissue development, cellular interaction and grow; resistant to support the weight of the newly formed tissue. Its versatile structure, physical and biochemical properties can be adjusted by adapting the bacteria culturing conditions. The main biomedical applications seem to be as hard (bone, dental), fibrocartilaginous (meniscal) and soft tissue (skin, cardiovascular, urinary) substituents. This paper reviews the current state of knowledge, challenges and future applications of BC and its biomedical potential in veterinary medicine. It was focused on the main uses in regeneration and scaffold tissue replacement and, although BC showed promising results, there is a lack of successful results of BC use in clinical practice. Most studies were performed only at experimental level and further research is needed for BC to enter clinical veterinary practice.

Bacterial nanocellulose: Present status, biomedical applications and future perspectives

Bacterial nanocellulose (BNC) has emerged as a natural biopolymer of significant importance in diverse technological areas due to its incredible physicochemical and biological characteristics. However, the high capital investments, production cost and lack of well-organized scale-up processes resulting in low BNC production are the major impediments need to be resolved. This review enfolds the three different and important portions of BNC. Firstly, advancement in production technologies of BNC like cell-free extract technology, static intermittent fed batch technology and novel cost-effective substrates that might surmount the barriers associated with BNC production at industrial level. Secondly, as BNC and its composites (with other polymers/nanoparticles) represents the utmost material of preference in current regenerative and diagnostic medicine, therefore recently reported biomedical applications of BNC and functionalized BNC in drug delivery, tissue engineering, antimicrobial wound healing and biosensing are widely been focused here. The third and the most important aspect of this review is an in-depth discussion of various pitfalls associated with BNC production. Recent trends in BNC research to overcome the existing snags that might pave a way for industrial scale production of BNC thereby facilitating its feasible application in various fields are highlighted.

Mechanical and Water-Resistant Properties of Eco-Friendly Chitosan Membrane Reinforced with Cellulose Nanocrystals

Environmentally benign and biodegradable chitosan (CS) membranes have disadvantages such as low mechanical strength, high brittleness, poor heat resistance and poor water resistance, which limit their applications. In this paper, home-made cellulose nanocrystals (CNC) were added to CS to prepare CNC/CS composite membranes through mechanical mixing and solution casting approaches. The effects of CNC dispersion patterns and CNC contents on the properties of composite membranes were studied. The analysis of the surface and cross-section morphology of the membranes showed that the dispersion performance of the composite membrane was better in the case that CNC was dissolved in an acetic acid solution and then mixed with chitosan by a homogenizer (Method 2). CNC had a great length-diameter ratio and CNC intensely interacted with CS. The mechanical properties of the composite membrane prepared with Method 2 were better. With a CNC content of 3%, the tensile strength of the composite membrane reached 43.0 MPa, 13.2% higher than that of the CNC-free membrane. The elongation at break was 41.6%, 56.4% higher than that of the CNC-free membrane. Thermogravimetric, contact angle and swelling analysis results showed that the addition of CNC could improve the heat and water resistance of the chitosan membrane.

Opportunities of Bacterial Cellulose to Treat Epithelial Tissues

In this mini-review, we highlight the potential of the biopolymer bacterial cellulose to treat damaged epithelial tissues. Epithelial tissues are cell sheets that delimitate both the external body surfaces and the internal cavities and organs. Epithelia serve as physical protection to underlying organs, regulate the diffusion of molecules and ions, secrete substances and filtrate body fluids, among other vital functions. Because of their continuous exposure to environmental stressors, damage to epithelial tissues is highly prevalent. Here, we first compare the properties of bacterial cellulose to the current gold standard, collagen, and then we examine the use of bacterial cellulose patches to heal specific epithelial tissues; the outer skin, the ocular surface, the oral mucosa and other epithelial surfaces. Special emphasis is made on the dermis since, to date, this is the most widespread medical use of bacterial cellulose. It is important to note that some epithelial tissues represent only the outermost layer of more complex structures such as the skin or the cornea. In these situations, depending on the penetration of the lesion, bacterial cellulose might also be involved in the regeneration of, for instance, inner connective tissue.

Novel Bionanocellulose/κ-Carrageenan Composites for Tissue Engineering

In this work, novel bacterial cellulose/κ-carrageenan (BNC/κ-Car) composites, being potential scaffolds for tissue engineering (TE), and outperforming the two polymers when used as scaffolds separately, were for the first time obtained using an in situ method, based on the stationary culture of bacteria Komagateibacter xylinus E25. The composites were compared with native BNC in terms of the morphology of fibers, chemical composition, crystallinity, tensile and compression strength, water holding capacity, water retention ratio and swelling properties. Murine chondrogenic ATDC5 cells were applied to assess the utility of the BNC/κ-Car composites as potential scaffolds. The impact of the composites on the cells viability, chondrogenic differentiation, and expression patterns of Col1α1, Col2α1, Runx2, and Sox9, which are indicative of ATDC5 chondrogenic differentiation, was determined. None of the composites obtained in this study caused the chondrocyte hypertrophy. All of them supported the differentiation of ATDC5 cells to more chondrogenic phenotype.