Proliferation of fibroblasts cultured on a hemi-cellulose dressing

A typical method for decellularization of plants as biomaterials

Decellularization is a process by which cells are removed from tissues or organs, leaving behind the extracellular matrix (ECM) structure. This process has gained interest in the fields of tissue engineering and regenerative medicine as a way to prepare suitable scaffolds for tissue reconstruction. Although the initial efforts come with the animal tissues, this technique can also be applied to various plant tissues with simple modifications, as plant-derived biomaterials have the benefit of being biocompatible and serving as a safe, all-natural substitute for synthetic or animal originated materials. Additionally, plant-derived biomaterials may help cells grow and differentiate, creating a three-dimensional environment for tissue regeneration and repair. Here we demonstrate a general method for plant tissue decellularization, including already experienced approaches and techniques.•Exhibit the basic steps for plant decellularization, which may be applied to several other plant tissues.•The proposed approach may be optimized considering various intended uses.•Gives basic information for the determination of decellularization efficiency.

Biopolymers Derived from Trees as Sustainable Multifunctional Materials: A Review

The world is currently transitioning from a fossil-fuel-driven energy economy to one that is supplied by more renewable and sustainable materials. Trees as the most abundant renewable bioresource have attracted significant attention for advanced materials and manufacturing in this epochal transition. Trees are composed with complex structures and components such as trunk (stem and bark), leaf, flower, seed, and root. Although many excellent reviews have been published regarding advanced applications of wood and wood-derived biopolymers in different fields, such as energy, electronics, biomedical, and water treatment, no reviews have revisited and systematically discussed functional materials and even devices derived from trees in a full scope yet. Therefore, a timely summary of the recent development of materials and structures derived from different parts of trees for sustainability is prsented here. A concise introduction to the different parts of the trees is given first, which is followed by the corresponding chemistry and preparation of functional materials using various biopolymers from trees. The most promising applications of biopolymer-based materials are discussed subsequently. A comprehensive review of the different parts of trees as sustainable functional materials and devices for critical applications is thus provided.

Onion Epithelial Membrane Scaffolds Transfer Corneal Epithelial Layers in Reconstruction Surgery

Plants and their extracts have been used especially in China for more than ten centuries for preventing and treating disease. However, there are only few reports describing their use in animal cell culture and tissue transplantation. In this study, onion epithelial membranes (OEM) is used as scaffolds to support cultures of a variety of cells such as fibroblasts and epithelial cells notably; they maintain the phenotypic characteristics of corneal epithelial cells. This improvement includes preservation of the proliferative potential and stemness of rabbit corneal epithelial cells (RCECs). Such an outcome suggests that this cost-effective technology warrants further evaluation to determine if OEM is a viable candidate for use as scaffolds in corneal epithelial transplantation surgery. To test this possibility, rabbit corneal epithelial cells expanded on OEM are transplanted to treat corneal epithelial defects in limbal stem cell deficient rabbits. This procedure is successful because it shortens the time required for wound healing to restore losses in corneal epithelial integrity, and forms a more compact and stratified epithelium framework than the untreated group. Ultimately, should they be proven to be effective in other relevant animal model systems, their usefulness for treating wounds in a clinical setting warrants consideration.

Clinical efficacy of biocellulose, carboxymethyl cellulose and normal saline dressing in epidermolysis bullosa

OBJECTIVE

To evaluate the efficacy of a biocellulose, a carboxymethyl cellulose and a normal saline wound dressing in the wound care management of epidermolysis bullosa (EB) skin wounds.

METHODS

This was a single-blind, randomised controlled trial involving wounds from patients with EB. Wounds were divided into three groups: group I with biocellulose wound dressing, group II with carboxymethyl cellulose wound dressing and group III with normal saline wound dressing as a control. All dressing changes and wound parameters were recorded. Observations were conducted every three days until complete wound closure or up to one month.

RESULTS

The outcomes of treatment of 36 wounds from four patients were evaluated in this study. Mean healing time in group I was seven days, eight days in group II and 14 days in group III. There were significant differences in healing times between group I and group III (p=0.0001) and between group II and III (p=0.001). The results showed a significant reduction in the percentage of wounds area on day three for each group: 51.7% in group I, 51.9% in group II, and 26% for group III. All wounds in groups I and II had healed at day 12 (100%) and at day 24 (100%) in group III. There were significant differences in the reduction of percentage wound area between group I and group III at day three (p=0.044) and day six (p=0.000), and between group II and III at day six (p=0.003).

CONCLUSION

The study demonstrates that both the biocellulose and the carboxymethyl cellulose wound dressings significantly reduced percentage wound areas and complete healing times compared with the normal saline wound dressing in EB skin wounds, demonstrating they are both equally good for wound care management in EB patients.

Crossing kingdoms: Using decellularized plants as perfusable tissue engineering scaffolds

Despite significant advances in the fabrication of bioengineered scaffolds for tissue engineering, delivery of nutrients in complex engineered human tissues remains a challenge. By taking advantage of the similarities in the vascular structure of plant and animal tissues, we developed decellularized plant tissue as a prevascularized scaffold for tissue engineering applications. Perfusion-based decellularization was modified for different plant species, providing different geometries of scaffolding. After decellularization, plant scaffolds remained patent and able to transport microparticles. Plant scaffolds were recellularized with human endothelial cells that colonized the inner surfaces of plant vasculature. Human mesenchymal stem cells and human pluripotent stem cell derived cardiomyocytes adhered to the outer surfaces of plant scaffolds. Cardiomyocytes demonstrated contractile function and calcium handling capabilities over the course of 21 days. These data demonstrate the potential of decellularized plants as scaffolds for tissue engineering, which could ultimately provide a cost-efficient, "green" technology for regenerating large volume vascularized tissue mass.

A Review of Water-Resistant Hemicellulose-Based Materials: Processing and Applications

Hemicelluloses, due to their hydrophilic nature, may tend to be overlooked as a component in water-resistant product applications. However, their domains of use can be greatly expanded by chemical derivatization. Research in which hydrophobic derivatives of hemicelluloses or combinations of hemicelluloses with hydrophobic materials are used with to prepare films and composites is considered herein. Isolation methods that have been used to separate hemicellulose from biomass are also reviewed. Finally, the most useful pathways to change the hydrophilic character of hemicelluloses to hydrophobic are reviewed. In this way, the water resistance can be increased and applications of targeted water-resistant hemicellulose developed. Several applications of these materials are discussed.

Fabrication of poly(ε-caprolactone)/keratin nanofibrous mats as a potential scaffold for vascular tissue engineering

The natural abundance of cell adhesion sequences, RGD (Arg-Gly-Asp) and LDV (Leu-Asp-Val) in the keratins make them suitable as biomaterials for tissue engineering applications. Herein, keratins were coelectrospun with poly(ε-caprolactone)(PCL) at the ratio of 9/1, 8/2, and 7/3 to afford nanofibrous mats. The resulting mats were surface-characterized by ATR-FTIR, SEM, WCA, and XPS. Cell attachment data showed that NIH 3T3 cells adhered more to the PCL/keratin nanofibrous mats than the pristine PCL mats. The MTT assay revealed that the PCL/keratin mats had improved cell viability. The blood clotting time test (APTT, PT, and TT) indicated the PCL/keratin mats exerted good blood compatibility. These mats would be a good candidate as a scaffold for vascular tissue engineering.

Novel wound dressing based on nanofibrous PHBV-keratin mats

Keratin is an important protein used for wound healing and tissue recovery. In this study, keratin was first extracted from raw materials and chemically modified to obtain stable keratin (m-keratin). The raw and m-keratin were examined by Raman spectroscopy. The molecular weight of the m-keratin was analysed by SDS-PAGE. The m-keratin was then blended with poly(hydroxybutylate-co-hydroxyvalerate) (PHBV) and electrospun to afford nanofibrous mats. These mats were characterized by field emission scanning electron microscopy (FE-SEM), electron spectroscopy for chemical analysis (ESCA) and atomic force microscopy (AFM). From the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) data, it was found that introduction of keratin enhanced cell proliferation. From wound-healing test and histological examination results, it was shown that the composite mats accelerated wound recovery remarkably as compared to the PHBV control. It was concluded that PHBV-keratin may be a good candidate as a wound dressing.

Hydroxyapatite bioactivated bacterial cellulose promotes osteoblast growth and the formation of bone nodules

The goal of this study was to investigate the feasibility of bacterial cellulose (BC) scaffold to support osteoblast growth and bone formation. BC was produced by culturing Acetobacter xylinum supplemented with hydroxyapatite (HA) to form BC membranes (without HA) and BC/HA membranes. Membranes were subjected to X-ray photoelectron spectroscopy (XPS) analysis to determine surface element composition. The membranes were further used to evaluate osteoblast growth, alkaline phosphatase activity and bone nodule formation. BC was free of calcium and phosphate. However, XPS analysis revealed the presence of both calcium (10%) and phosphate (10%) at the surface of the BC/HA membrane. Osteoblast culture showed that BC alone was non-toxic and could sustain osteoblast adhesion. Furthermore, osteoblast adhesion and growth were significantly (p ≤0.05) increased on BC/HA membranes as compared to BC alone. Both BC and BC/HA membranes improved osteoconductivity, as confirmed by the level of alkaline phosphatase (ALP) activity that increased from 2.5 mM with BC alone to 5.3 mM with BC/HA. BC/HA membranes also showed greater nodule formation and mineralization than the BC membrane alone. This was confirmed by Alizarin red staining (ARS) and energy dispersive X-ray spectroscopy (EDX). This work demonstrates that both BC and BC/HA may be useful in bone tissue engineering.

Effects of different extracellular matrices and growth factor immobilization on biodegradability and biocompatibility of macroporous bacterial cellulose

To improve the biocompatibility of bacterial cellulose hydrogel (BCHG), different extracellular matrices (ECMs; collagen, elastin, and hyaluronan) and growth factors (B-FGF, H-EGF, and KGF) were immobilized onto macroporous BCHG. The microstructure of BCHG had inter-connective channels that were well-integrated with the alginate gel. The alginate gel formed a semi-penetrate hydrogel that allowed the ECM and growth factor to diffuse under physiological conditions. The H-EGF and collagen-modified BCHG supported the growth of human skin fibroblast. The improved BCHG was biocompatible and exhibited desirable skin substitute characteristics that could be used as a deliver vehicle for therapeutic compounds during wound healing.

Efficiency of microbial cellulose dressing in partial-thickness burn wounds

Microbial cellulose is a natural polymer that can hold a quantity of water without any disconformities. Therefore, it is proposed for use as wound dressing material. We report a case of 28% total body surface area partial-thickness flame burn: approximately 4.5% superficial partial-thickness burns on anterior face and 23.5% combined superficial and deep partial-thickness burns on both upper arms and anterior trunk. A microbial cellulose dressing, Nanocell (Thai Nano Cellulose Co Ltd, Bangkok, Thailand), was applied to the face wound only once, without any further dressing change. Progress of healing, until full epithelialization on the face, was observed for 2 weeks. During the treatment period, the patient did not show any irritation or allergic reaction to this new dressing, and wound swab culture showed no evidence of bacteria presence. This innovative material can be an alternative dressing for superficial partial-thickness burn wounds.

Microcrystalline cellulose membrane for re-epithelisation of chronic leg wounds: a prospective open study

Treatment of chronic leg ulcers remains a major health care issue. Although many reports have examined different topical dressings, none have specifically looked at microcrystalline cellulose (MCC). We aimed to evaluate in a prospective, open study the safety and performance of a MCC membrane (Veloderm) in a series of chronic leg wounds of different aetiology. Fifty-five patients participated in this study. The membrane was applied every 5-10 days for 1 month, immediately after surgical debridement. The wound bed was assessed on days 7, 15 and 30 for erythema, pain, exudate level and infection. The wound size change at 30 days was the primary efficacy parameter and any adverse events were collected and analysed. A wound size change of 55% was achieved at the end of follow-up, with an improvement in all the collected parameters, but the erythema, which showed a mild increase. To date, this is the largest experience with a MCC product in chronic wounds. Our study suggests that this treatment may be safe and useful and deserves further investigation.