Surface controlled calcium phosphate formation on three-dimensional bacterial cellulose-based nanofibers

Dual photothermal nanocomposites for drug-resistant infectious wound management

Management of antibiotic-resistant bacteria-induced skin infections for rapid healing remains a critical clinical challenge. Photothermal therapy, which uses mediated hyperthermia to combat such problems, has recently been recognised as a promising approach to take. In this study, bacterial cellulose-based photothermal membranes were designed and developed to combat bacterial infections and promote rapid wound healing. Polydopamine was incorporated into gold nanoparticles to produce superior dual-photothermal behaviour. The in vitro antibacterial efficacy of the prepared composite membranes against S. aureus, E. coli and methicillin-resistant Staphylococcus aureus (MRSA) could reach 99% under near-infrared (NIR) irradiation. In addition, the synthesised nanocomposite exhibited good biocompatibility in vitro as demonstrated by a cell survival ratio of >85%. The effectiveness of the composite membranes on wound healing was further investigated in a murine model of MRSA-infected wounds, focusing on the effect of photothermal temperature. According to the detailed therapeutic mechanism study undertaken, the composite membranes cause bacterial killing initially and promote the transition from the inflammatory phase to proliferation by suppressing pro-inflammatory cytokine production, promoting collagen deposition, and stimulating angiogenesis. Considering their remarkable effectiveness and facile fabrication process, it is expected that these novel materials could serve as competitive multifunctional dressings in the management of infectious wounds and accelerate the regeneration of damaged tissues related to abnormal immune responses.

Mineralization of phosphorylated cellulose/sodium alginate sponges as biomaterials for bone tissue engineering

The incorporation of SA in the cellulose matrix effectively increased the macroporous ability of composite scaffolds. Furthermore, the phosphorylation has a certain induction capability for the growth of HA.

Bone-Inspired Mineralization with Highly Aligned Cellulose Nanofibers as Template

Bioinspired by the aligned structure and building blocks of bone, this work mineralized the aligned bacterial cellulose (BC) through in situ mineralization using CaCl₂ and K₂HPO₄ solutions. The cellulose nanofibers were aligned by a scalable stretching process. The aligned and mineralized bacterial cellulose (AMBC) homogeneously incorporated hydroxyapatite (HAP) with a high mineral content and exhibited excellent mechanical strength. The ordered 3D structure allowed the AMBC composite to achieve a high elastic modulus and hardness and the development of a nanostructure inspired by natural bone. The AMBC composite exhibited an elastic modulus of 10.91 ± 3.26 GPa and hardness of 0.37 ± 0.18 GPa. Compared with the nonaligned mineralized bacterial cellulose (NMBC) composite with mineralized crystals of HAP randomly distributed into the BC scaffolds, the AMBC composite possessed a 210% higher elastic modulus and 95% higher hardness. The obtained AMBC composite had excellent mechanical properties by mimicking the natural structure of bone, which indicated that the organic BC aerogel with aligned nanofibers was a promising template for biomimetic mineralization.

Macroporous bacterial cellulose grafted by oligopeptides induces biomimetic mineralization via interfacial wettability

Bacterial cellulose (BC) has a role in tissue repair and regenerative medicine, which has already attracted tremendous interest from researchers, especially those working in the field of hybrid materials. Herein, we designed BC-based macroporous functional materials by dialdehyde bacterial cellulose (DBC) cross-linking with oligopeptides under mild reactive conditions. The interfacial properties of the surface modified BC were examined by biomimetic mineralization. The results showed that a macroporous structure was achieved by using oligopeptides as chemical cross-linking agents with an interconnected macroporosity ranging from 20 μm to 80 μm. Their mechanical properties were barely altered compared to the pristine BC. Their enhanced surface charges stemmed from the carboxyl groups of the oligopeptides engaging in reactions with amine and aldehyde groups. The oligopeptides cross-linked DBC showed a faster initial induction towards minerals via interfacial wettability resulting in promotion of mineralization, the hybrid materials had excellent biocompatibility relative to the pristine BC. These findings are vital to the development of other biopolymers with essential macroporous structures as well as improved interfacial wettability, which enables their possible uses in tissue repair and regenerative medicine.

Novel surface modification of three-dimensional bacterial nanocellulose with cell-derived adhesion proteins for soft tissue engineering

Bacterial nanocellulose (BNC) is a natural polymer composed of glucose units with an important application as a two and three-dimensional scaffold for tissue engineering. However, as a polysaccharide, BNC does not have the biological signals of protein biomaterials. Therefore, this paper aims to develop a novel methodology to biomimic soft extracellular matrix (ECM) chemistry on to 3D BNC using the bioengineering of fibroblasts (the cells responsible for producing and regenerating the ECM) to immobilise adhesion proteins such as collagen and fibronectin. Modified 3D BNC (Mod-BNC) biomaterials were morphologically, thermally, and chemically characterised, and furthermore, the cell response was analysed by adhesion studies using atomic force microscopy (AFM), XTT assay, and confocal microscopy. Cell-derived proteins were deposited on the BNC nanoribbon network to modify its surface. The contact angle was increased from 40° to 60°, reducing the wettability of the biomaterial, and during thermogravimetry, the proteins in Mod-BNC exhibited an enhanced thermal stability because of the interactions between themselves and BNC. Chemical and immunocytochemistry analyses confirmed the presence of collagen type I and fibronectin on 3D BNC. These proteins activate integrin adhesion pathways that generate stronger cell adhesions. AFM experiments showed higher forces and energies on modified biomaterials, and moreover, the cells that adhered on to Mod-BNC exhibited higher mitochondrial activity and higher cell populations per cubic millimetre than non-modified surfaces (NMod-BNC). Accordingly, it was established that this novel methodology is robust and able to biomimic the chemical surface of soft ECM and immobilise cell-derived adhesion proteins from fibroblast; moreover, the Mod-BNC exhibited better cell response than NMod-BNC because of the biological signals in 3D BNC.

The facile synthesis and bioactivity of a 3D nanofibrous bioglass scaffold using an amino-modified bacterial cellulose template

Porous bioglass (BG) scaffolds are of great importance in tissue engineering because of their excellent osteogenic properties for bone regeneration. Herein, we reported for the first time the use of amino-modified bacterial cellulose (NBC) as a template to prepare a three-dimensional (3D) nanofibrous BG scaffold by a facile modified sol–gel approach under ultrasonic treatment. The results suggested that the amino groups on the BC template could effectively promote the absorption of the deposited CaO and SiO₂ precursors, and the as-obtained BG scaffold showed a 3D interconnected porous network structure consisting of nanofibers with a diameter of about 20 nm. Furthermore, the as-obtained BG scaffold showed very good bioactivity after being immersed in SBF for 7 days. This research provides a facile and efficient way to prepare a nanofibrous BG scaffold with 3D porous structure, which can be used as a promising candidate for biomedical applications.

A nanofibrous BG scaffold with a high quality 3D porous interconnected structure has been prepared via a facile modified sol–gel approach using amino-modified bacterial cellulose as the template.

Mineralization of a superficially porous microsphere scaffold via plasma modification

Novel porous mineralization layers were obtained on scaffolds. The plasma process could enhance the bonding force between apatite and the substrate surface.

In Vitro Studies of Bacterial Cellulose and Magnetic Nanoparticles Smart Nanocomposites for Efficient Chronic Wounds Healing

The quality of life of patients with chronic wounds can be extremely poor and, therefore, over the past decades, great efforts have been made to develop efficient strategies to improve the healing process and the social impact associated with these conditions. Cell based therapy, as a modern tissue engineering strategy, involves the design of 3D cell-scaffold bioconstructs obtained by preseeding drug loaded scaffolds with undifferentiated cells in order to achieve in situ functional de novo tissue. This paper reports on the development of bionanocomposites based on bacterial cellulose and magnetic nanoparticles (magnetite) for efficient chronic wounds healing. Composites were obtained directly in the cellulose bacterial culture medium by dispersing various amounts of magnetite nanoparticles during the biosynthesis process. After purification and drying, the membranes were characterized by Raman spectroscopy and X-ray diffraction to reveal the presence of magnetite within the bacterial cellulose matrix. Morphological investigation was employed through SEM and TEM analyses on bionanocomposites. The biocompatibility of these innovative materials was studied in relation to human adipose derived stem cells in terms of cellular morphology, viability, and proliferation as well as scaffolds cytotoxic potential.

The relationship between microstructure and in vivo degradation of modified bacterial cellulose sponges

The interaction between the nanofibers of bacterial cellulose and hydroxyapatite has an extensive influence on the microstructure and the macroscopic properties of this type of composite, but the structural anisotropy and the speed of granulation ingrowth are strongly interdependent.