Sugar-cane bagasse derived cellulose enhances performance of polylactide and polydioxanone electrospun scaffold for tissue engineering

Lignin-cellulose complexes derived from agricultural wastes for combined antibacterial and tissue engineering scaffolds for cutaneous leishmaniasis wounds

Bacterial infections in wounds significantly impair the healing process. The use of natural antibacterial products over synthetic antibiotics has emerged as a new trend to address antimicrobial resistance. An ideal tissue engineering scaffold to treat infected wounds should possess antibacterial properties, while simultaneously promoting tissue regrowth. Synthesis of hydrogel scaffolds with antibacterial properties using hemp shive (HT1/HT2) lignin, sugarcane bagasse (SCB) lignin and cellulose was carried out. All lignin samples had low molecular weights and were constituted of G-type β-5 dimers, linked by β-O-4 bonds, as determined by MALDI-TOF-MS. Hemp lignin was more cytotoxic to mouse fibroblasts (L929) compared to SCB lignin. All lignin samples demonstrated antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, with greater efficiency against Gram-negative strains. 3D hydrogels were engineered by crosslinking SCB lignin with SCB cellulose in varying weight ratios in the presence of epichlorohydrin. The stiffness of the hydrogels could be tailored by varying the lignin concentration. All hydrogels were biocompatible; however, better fibroblast adhesion was observed on the blended hydrogels compared to the 100% cellulose hydrogel, with the cellulose : lignin 70 : 30 hydrogel showing the highest L929 proliferation and best antibacterial properties with a 24-hour bacterial growth reduction ranging from 30.8 to 57.3%.

Electrospun polydioxanone/fucoidan blend nanofibers loaded with anti-cancer precipitate from Jaspis diastra and paclitaxel: Physico-chemical characterization and in-vitro screening

Nanofibers for drug delivery systems have gained much attention during the past years. This paper describes for the first time the loading of a bioactive precipitate (JAD) from the marine sponge Jaspis diastra in PDX and fucoidan-PDX. JAD was characterized by LC-MS/MS and the major component was jaspamide (1) with a purity of 62.66 %. The cytotoxicity of JAD was compared with paclitaxel (PTX). JAD and PTX displayed IC50 values of 1.10 ± 0.7 μg/mL and 0.21 ± 0.12 μg/mL on skin fibroblasts L929 cells whilst their IC50 values on uveal MP41 cancer cells, were 2.10 ± 0.55 μg/mL and 1.38 ± 0.68 μg/mL, respectively. JAD was found to be less cytotoxic to healthy fibroblasts compared to PTX. JAD and PTX loaded scaffolds showed sustained release over 96 h in physiological medium which is likely to reduce the secondary cytotoxic effect induced by JAD and PTX alone. The physico-chemical properties of the loaded and unloaded scaffolds together with their degradation and action on tumor microenvironment by using L929 and MP41 cells were investigated. JAD and PTX at a concentration of 0.5 % (drug/polymer, w/w) in the electrospun mats prevented growth and proliferation of L929 and MP41 cells. Co-culture of L929 and MP41 showed that the JAD and PTX loaded mats inhibited the growth of both cells and caused cell death.

Cassava microfiber-reinforced gelatin scaffold holds promise for tissue engineering by exhibiting cytocompatibility with HEK 293 cells

Cellulose fiber-reinforced composite scaffolds have recently become an interesting target for biomedical and tissue engineering (TE) applications. Cassava bagasse, a fibrous solid residue obtained after the extraction of cassava starch and soluble sugars, has been explored as a potential source of cellulose and has been successfully used to enhance the mechanical properties of gelatin scaffolds for TE purposes. This study assessed the cytocompatibility of the cassava microfiber-gelatin composite scaffold using human embryonic kidney cells (HEK 293) and a breast cancer cell line (MDA MB 231) under ISO 10993-5 standards. The viability of cells within the composite scaffold was analyzed through MTT assay. The growth of HEK 293, as well as the cell morphology, was not affected by the presence of cellulose within the composite, whereas the growth of breast cancer cells appeared to be inhibited with noticeable changes in cell morphology. These findings suggest that the presence of the cassava fiber in gelatin is not cytotoxic to HEK 293 cells. Thus, the composite is suitable for TE purposes when using normal cells. On the contrary, the presence of the fiber in gelatin elicited a cytotoxic effect in MDA MB 231 cells. Thus, the composite may not be considered for three-dimensional (3D) tumor cell studies requiring cancer cell growth. However, further studies are required to explore the use of the fiber from cassava bagasse for its anticancer cell properties, as observed in this study.

Design and development of polydioxanone scaffolds for skin tissue engineering manufactured via green process

Fiber spinning technologies attracted a great interest since the beginning of the last century. Among these, electrospinning is a widely diffuse technique; however, it presents some drawbacks such as low fiber yield, high energy demand and the use of organic solvents. On the contrary, centrifugal spinning is a more sustainable method and allows to obtain fiber using centrifugal force and melted materials. The aim of the present work was the design and the development of polydioxanone (PDO) microfibers intended for tissue engineering, using centrifugal spinning. PDO, a bioresorbable polymer currently used for sutures, was selected as low melting polyester and DES (deep eutectic solvents), either choline chloride/citric acid (ChCl/CA) or betaine/citric acid (Bet/CA) 1:1 M ratio, were used to improve PDO spinnability. Physical mixtures of DES and PDO were prepared using different weight ratios. These were then poured into the spinneret and melted at 140 °C for 5 min. After the complete melting, the blends were spun for 1 min at 700 rpm. The fibers were characterized for physico chemical properties (morphology; dimensions; chemical structure; thermal behavior; mechanical properties). Moreover, the preclinical investigation was performed in vitro (biocompatibility, adhesion and proliferation of fibroblasts) and in vivo (murine burn/excisional model to assess safety and efficacy). The multidisciplinary approach allowed to obtain an extensive characterization to develop PDO based microfibers as medical device for implant to treat full thickness skin wounds.

Preparation and research of PCL/cellulose composites: Cellulose derived from agricultural wastes

For the rational use of agricultural wastes, bagasse, orange peel and wheat bran were used to fabricate bio-based polymer materials. Cellulose was extracted from the three different agricultural wastes, and poly(ε-caprolactone) (PCL) was used as the matrix material. PCL was mixed with nanocrystalline cellulose (CNC), extracted bagasse cellulose (GC), orange peel cellulose (JC) and wheat bran cellulose (MC) by solution casting. Morphology and structure of the extracted cellulose were studied by Scanning Electron Microscope, Fourier Infrared spectrometer, thermogravimetry and X-ray diffractometer. The influence of GC, JC, MC on the crystallization process and mechanical properties of PCL was investigated by DSC and tensile test. Experimental results show that the addition of CNC, GC, JC, MC increases the crystallization temperature of PCL, accelerates the crystallization process of PCL, and improves the tensile property of PCL.

Cellulose-Based Composites as Scaffolds for Tissue Engineering: Recent Advances

Today, numerous studies have focused on the design of novel scaffolds for tissue engineering and regenerative medicine applications; however, several challenges still exist in terms of biocompatibility/cytocompatibility, degradability, cell attachment/proliferation, nutrient diffusion, large-scale production, and clinical translation studies. Greener and safer technologies can help to produce scaffolds with the benefits of cost-effectiveness, high biocompatibility, and biorenewability/sustainability, reducing their toxicity and possible side effects. However, some challenges persist regarding their degradability, purity, having enough porosity, and possible immunogenicity. In this context, naturally derived cellulose-based scaffolds with high biocompatibility, ease of production, availability, sustainability/renewability, and environmentally benign attributes can be applied for designing scaffolds. These cellulose-based scaffolds have shown unique mechanical properties, improved cell attachment/proliferation, multifunctionality, and enhanced biocompatibility/cytocompatibility, which make them promising candidates for tissue engineering applications. Herein, the salient developments pertaining to cellulose-based scaffolds for neural, bone, cardiovascular, and skin tissue engineering are deliberated, focusing on the challenges and opportunities.

The latest achievements in plant cellulose-based biomaterials for tissue engineering focusing on skin repair

The present work reviews recent developments in plant cellulose-based biomaterial design and applications, properties, characterizations, and synthesis for skin tissue engineering and wound healing. Cellulose-based biomaterials are promising materials for their remarkable adaptability with three-dimensional polymeric structure. They are capable of mimicking tissue properties, which plays a key role in tissue engineering. Besides, concerns for environmental issues have motivated scientists to move toward eco-friendly materials and natural polymer-based materials for applications in the tissue engineering field these days. Therefore, cellulose as an appropriate substitute for common polymers based on crude coal, animal, and human-derived biomolecules is greatly considered for various applications in biomedical fields. Generally, natural biomaterials lack good mechanical properties for skin tissue engineering. But using modified cellulose-based biopolymers tackles these restrictions and prevents immunogenic responses. Moreover, tissue engineering is a quick promoting field focusing on the generation of novel biomaterials with modified characteristics to improve scaffold function through physical, biochemical, and chemical tailoring. Also, nanocellulose with a broad range of applications, particularly in tissue engineering, advanced wound dressing, and as a material for coupling with drugs and sensorics, has been reviewed here. Moreover, the potential cytotoxicity and immunogenicity of cellulose-based biomaterials are addressed in this review.

Surface-Modified Nanocellulose for Application in Biomedical Engineering and Nanomedicine: A Review

Presently, a plenty of concerns related to the environment are due to the overuse of petroleum-based chemicals and products; the synthesis of functional materials, starting from the natural sources, is the current trend in research. The interest for nanocellulose has recently increased in a huge range of fields, from the material science to the biomedical engineering. Nanocellulose gained this leading role because of several reasons: its natural abundance on this planet, the excellent mechanical and optical features, the good biocompatibility and the attractive capability of undergoing surface chemical modifications. Nanocellulose surface tuning techniques are adopted by the high reactivity of the hydroxyl groups available; the chemical modifications are mainly performed to introduce either charged or hydrophobic moieties that include amination, esterification, oxidation, silylation, carboxymethylation, epoxidation, sulfonation, thiol- and azido-functional capability. Despite the several already published papers regarding nanocellulose, the aim of this review involves discussing the surface chemical functional capability of nanocellulose and the subsequent applications in the main areas of nanocellulose research, such as drug delivery, biosensing/bioimaging, tissue regeneration and bioprinting, according to these modifications. The final goal of this review is to provide a novel and unusual overview on this topic that is continuously under expansion for its intrinsic sophisticated properties.

Correlating in vitro performance with physico-chemical characteristics of nanofibrous scaffolds for skin tissue engineering using supervised machine learning algorithms

The engineering of polymeric scaffolds for tissue regeneration has known a phenomenal growth during the past decades as materials scientists seek to understand cell biology and cell-material behaviour. Statistical methods are being applied to physico-chemical properties of polymeric scaffolds for tissue engineering (TE) to guide through the complexity of experimental conditions. We have attempted using experimental in vitro data and physico-chemical data of electrospun polymeric scaffolds, tested for skin TE, to model scaffold performance using machine learning (ML) approach. Fibre diameter, pore diameter, water contact angle and Young's modulus were used to find a correlation with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of L929 fibroblasts cells on the scaffolds after 7 days. Six supervised learning algorithms were trained on the data using Seaborn/Scikit-learn Python libraries. After hyperparameter tuning, random forest regression yielded the highest accuracy of 62.74%. The predictive model was also correlated with in vivo data. This is a first preliminary study on ML methods for the prediction of cell-material interactions on nanofibrous scaffolds.

A new PEGDA/CNF aerogel-wet hydrogel scaffold fabricated by a two-step method

The scaffold is one of the most important components in tissue engineering. There are a lot of natural or synthetic materials applied for the fabrication of scaffolds. Among them, cellulose nanofibril (CNF) is an important natural polymer with characteristics of superior biocompatibility, notable nanostructure effect and excellent hydrophilia, which make it qualified for serving as a raw material of scaffolds. In this paper, polyethylene glycol diacrylate (PEGDA) was mixed with CNF at different content ratios, which were 0%, 0.35%, 0.7%, 1.05% and 1.4% (m/v). Furthermore, the visible light photoinitiator (eosin Y + TEA + NVP) was first added to this mixture solution to form a new kind of bio-resin. A two-step method including stereolithography and freeze-drying is put forward to fabricate a new aerogel-wet hydrogel scaffold. Scaffolds were fabricated by using a self-built stereolithography platform and the mechanical properties, printability and biocompatibility of the hydrogel scaffolds were investigated thoroughly. The original hydrogel scaffold was fabricated through stereolithography, where CNFs were applied to regulate the mechanical properties of the hydrogel and the printability of the bio-resin. After the freeze-drying process, the original hydrogel was transformed into the aerogel-wet hydrogel whose compressive modulus is reduced by 20%. Furthermore, the surface structure of the hydrogel scaffold is modified to provide a better environment for adhesion and growth of BMSc.

Versatile Application of Nanocellulose: From Industry to Skin Tissue Engineering and Wound Healing

Nanocellulose is cellulose in the form of nanostructures, i.e., features not exceeding 100 nm at least in one dimension. These nanostructures include nanofibrils, found in bacterial cellulose; nanofibers, present particularly in electrospun matrices; and nanowhiskers, nanocrystals, nanorods, and nanoballs. These structures can be further assembled into bigger two-dimensional (2D) and three-dimensional (3D) nano-, micro-, and macro-structures, such as nanoplatelets, membranes, films, microparticles, and porous macroscopic matrices. There are four main sources of nanocellulose: bacteria (Gluconacetobacter), plants (trees, shrubs, herbs), algae (Cladophora), and animals (Tunicata). Nanocellulose has emerged for a wide range of industrial, technology, and biomedical applications, namely for adsorption, ultrafiltration, packaging, conservation of historical artifacts, thermal insulation and fire retardation, energy extraction and storage, acoustics, sensorics, controlled drug delivery, and particularly for tissue engineering. Nanocellulose is promising for use in scaffolds for engineering of blood vessels, neural tissue, bone, cartilage, liver, adipose tissue, urethra and dura mater, for repairing connective tissue and congenital heart defects, and for constructing contact lenses and protective barriers. This review is focused on applications of nanocellulose in skin tissue engineering and wound healing as a scaffold for cell growth, for delivering cells into wounds, and as a material for advanced wound dressings coupled with drug delivery, transparency and sensorics. Potential cytotoxicity and immunogenicity of nanocellulose are also discussed.

Modulating matrix-multicellular response using polysucrose-blended with poly-L-lactide or polydioxanone in electrospun scaffolds for skin tissue regeneration

Polysucrose (PSuc) is hydrophilic, has excellent biocompatibility with cells as a density gradient and is resistant to enzymes. Its use in electrospun mats for tissue engineering applications has not been investigated due to its amorphous nature. For spinnability and robustness, polysucrose was blended with poly-L-lactide (PLLA) and polydioxanone (PDX) respectively and electrospun into nanofibrous mats. Interaction with cells was assessed using L929 mouse fibroblasts and HaCaT keratinocytes separately and in co-culture. Effect of parameters such as porosity, fiber diameter, surface wettability and mechanical properties of mats on cell-scaffold interactions was studied. Depending on nature and composition of mats, fibroblasts showed dendritic, spindle or round cell morphologies along with the formation of lamellipodia, filopodia, fibrillar or fiber-like projections of 100 nm and 200-300 nm in diameter respectively from the periphery or center of cells. Granular extracellular matrix was formed on both PLLA-PSuc and PDX-PSuc 50-50 seeded with keratinocytes. Growth of keratinocytes was enhanced in co-culture with fibroblasts with the formation of a skin-like layer. Both cells showed the ability to form multilayer structures. The mats maintained their physical integrity during the period of study. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3275-3291, 2018.

Recent Advances in Modified Cellulose for Tissue Culture Applications

Tissue engineering is a rapidly advancing field in regenerative medicine, with much research directed towards the production of new biomaterial scaffolds with tailored properties to generate functional tissue for specific applications. Recently, principles of sustainability, eco-efficiency and green chemistry have begun to guide the development of a new generation of materials, such as cellulose, as an alternative to conventional polymers based on conversion of fossil carbon (e.g., oil) and finding technologies to reduce the use of animal and human derived biomolecules (e.g., foetal bovine serum). Much of this focus on cellulose is due to it possessing the necessary properties for tissue engineering scaffolds, including biocompatibility, and the relative ease with which its characteristics can be tuned through chemical modification to adjust mechanical properties and to introduce various surface modifications. In addition, the sustainability of producing and manufacturing materials from cellulose, as well as its modest cost, makes cellulose an economically viable feedstock. This review focusses specifically on the use of modified cellulose materials for tissue culturing applications. We will investigate recent techniques used to promote scaffold function through physical, biochemical and chemical scaffold modifications, and describe how these have been utilised to reduce reliance on the addition of matrix ligands such as foetal bovine serum.

Electrospun and Electrosprayed Scaffolds for Tissue Engineering

Electrospinning and electrospraying technologies provide an accessible and universal synthesis method for the continuous preparation of nanostructured materials. This chapter introduces recent uses of electrospun and electrosprayed scaffolds for tissue regeneration applications. More recent in vitro and in vivo of electrospun fibers are also discussed in relation to soft and hard tissue engineering applications. The focus is made on the bone, vascular, skin, neural and soft tissue regeneration. An introduction is presented regarding the production of biomaterials made by synthetic and natural polymers and inorganic and metallic materials for use in the production of scaffolds for regenerative medicine. For this proposal, the following techniques are discussed: electrospraying, co-axial and emulsion electrospinning and bio-electrospraying. Tissue engineering is an exciting and rapidly developing field for the understanding of how to regenerate the human body.