Cellulose membrane as a biomaterial: from hydrolysis to depolymerization with electron beam

A Sacrificial Linker in Biodegradable Polyesters for Accelerated Photoinduced Degradation, Monitored by Continuous Atline SEC Analysis

Polymeric materials that undergo photoinduced degradation have wide application in fields such as controlled release. Most methods for photoinduced degradation rely on the UV or near-UV region of the electromagnetic spectrum; however, use of the deeply penetrating and benign wavelengths of visible light offers a multitude of advantages. Here we report a lactone monomer for ring-opening copolymerizations to introduce a sacrificial linker into a polymer backbone which can be cleaved by reactive oxygen species which are produced by a photocatalyst under visible light irradiation. We find that copolymers of this material readily degrade under visible light. We followed polymer degradation using a continuous flow size exclusion chromatography system, the components of which are described herein.

Water-Driven Sol-Gel Transition in Native Cellulose/1-Ethyl-3-methylimidazolium Acetate Solutions

The addition of water to native cellulose/1-ethyl-3-methylimidazolium acetate solutions catalyzes the formation of gels, where polymer chain-chain intermolecular associations act as cross-links. However, the relationship between water content (Wc), polymer concentration (Cp), and gel strength is still missing. This study provides the fundamentals to design water-induced gels. First, the sol-gel transition occurs exclusively in entangled solutions, while in unentangled ones, intramolecular associations hamper interchain cross-linking, preventing the gel formation. In entangled systems, the addition of water has a dual impact: at low water concentrations, the gel modulus is water-independent and controlled by entanglements. As water increases, more cross-links per chain than entanglements emerge, causing the modulus of the gel to scale as Gp ∼ Cp2Wc3.0±0.2. Immersing the solutions in water yields hydrogels with noncrystalline, aggregate-rich structures. Such water-ionic liquid exchange is examined via Raman, FTIR, and WAXS. Our findings provide avenues for designing biogels with desired rheological properties.

Recent advances in cellulose supported photocatalysis for pollutant mitigation: A review

In recent times, green chemistry or "green world" is a new and effective approach for sustainable environmental remediation. Among all biomaterials, cellulose is a vital material in research and green chemistry. Cellulose is the most commonly used natural biopolymer because of its distinctive and exceptional properties such as reproducibility, cost-effectiveness, biocompatibility, biodegradability, and universality. Generally, coupling cellulose with other nanocomposite materials enhances the properties like porosity and specific surface area. The polymer is environment-friendly, bioresorbable, and sustainable which not only justifies the requirements of a good photocatalyst but boosts the adsorption ability and degradation efficiency of the nanocomposite. Hence, knowing the role of cellulose to enhance photocatalytic activity, the present review is focused on the properties of cellulose and its application in antibiotics, textile dyes, phenol and Cr(VI) reduction, and degradation. The work also highlighted the degradation mechanism of cellulose-based photocatalysts, confirming cellulose's role as a support material to act as a sink and electron mediator, suppressing the charge carrier's recombination rate and enhancing the charge migration ability. The review also covers the latest progressions, leanings, and challenges of cellulose biomaterials-based nanocomposites in the photocatalysis field.

Comparative hydrolysis analysis of cellulose samples and aspects of its application in conservation science

Knowledge about the carbohydrate composition of pulp and paper samples is essential for their characterization, further processing, and understanding the properties. In this study, we compare sulfuric acid hydrolysis and acidic methanolysis, followed by GC-MS analysis of the corresponding products, by means of 42 cellulose and polysaccharide samples. Results are discussed and compared to solid-state NMR (crystallinity) and gel permeation chromatography (weight-averaged molecular mass) data. The use of the hydrolysis methods in the context of cellulose conservation science is evaluated, using e-beam treated and artificially aged cellulose samples.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10570-021-04048-6.

Symbiotic Photosynthetic Oxygenation within 3D-Bioprinted Vascularized Tissues

In this study, we present the photosynthetic oxygen (O2) supply to mammalian cells within a volumetric extracellular matrix-like construct, whereby a three-dimensional (3D)-bioprinted fugitive pattern encapsulating unicellular green algae, Chlamydomonas reinhardtii (C. reinhardtii), served as a natural photosynthetic O2-generator. The presence of bioprinted C. reinhardtii enhanced the viability and functionality of mammalian cells while reducing the hypoxic conditions within the tissues. We were able to subsequently endothelialize the hollow perfusable microchannels formed after enzymatic removal of the bioprinted C. reinhardtii-laden patterns from the matrices following the initial oxygenation period, to obtain biologically relevant vascularized mammalian tissue constructs. The feasibility of co-culture of C. reinhardtii with human cells, the printability and the enzymatic degradability of the fugitive bioink, as well as the exploration of C. reinhardtii as a natural, eco-friendly, cost-effective, and sustainable source of O2 would likely promote the development of engineered tissues, tissue models, and food for various applications.

Electrospun cellulose acetate butyrate/polyethylene glycol (CAB/PEG) composite nanofibers: A potential scaffold for tissue engineering

Electrospinning is a common method to prepare nanofiber scaffolds for tissue engineering. One of the common cellulose esters, cellulose acetate butyrate (CAB), has been electrospun into nanofibers and studied. However, the intrinsic hydrophobicity of CAB limits its application in tissue engineering as it retards cell adhesion. In this study, the properties of CAB nanofibers were improved by fabricating the composite nanofibers made of CAB and hydrophilic polyethylene glycol (PEG). Different ratios of CAB to PEG were tested and only the ratio of 2:1 resulted in smooth and bead-free nanofibers. The tensile test results show that CAB/PEG composite nanofibers have 2-fold higher tensile strength than pure CAB nanofibers. The hydrophobicity of the composite nanofibers was also reduced based on the water contact angle analysis. As the hydrophilicity increases, the swelling ability of the composite nanofiber increases by 2-fold with more rapid biodegradation. The biocompatibility of the nanofibers was tested with normal human dermal fibroblasts (NHDF). The cell viability assay results revealed that the nanofibers are non-toxic. In addition to that, CAB/PEG nanofibers have better cell attachment compared to pure CAB nanofibers. Based on this study, CAB/PEG composite nanofibers could potentially be used as a nanofiber scaffold for applications in tissue engineering.

Naturally-Derived Biomaterials for Tissue Engineering Applications

Naturally-derived biomaterials have been used for decades in multiple regenerative medicine applications. From the simplest cell microcarriers made of collagen or alginate, to highly complex decellularized whole-organ scaffolds, these biomaterials represent a class of substances that is usually first in choice at the time of electing a functional and useful biomaterial. Hence, in this chapter we describe the several naturally-derived biomaterials used in tissue engineering applications and their classification, based on composition. We will also describe some of the present uses of the generated tissues like drug discovery, developmental biology, bioprinting and transplantation.

Bio Mimicking of Extracellular Matrix

Biomaterials play a critical role in regenerative strategies such as stem cell-based therapies and tissue engineering, aiming to replace, remodel, regenerate, or support damaged tissues and organs. The design of appropriate three-dimensional (3D) scaffolds is crucial for generating bio-inspired replacement tissues. These scaffolds are primarily composed of degradable or non-degradable biomaterials and can be employed as cells, growth factors, or drug carriers. Naturally derived and synthetic biomaterials have been widely used for these purposes, but the ideal biomaterial remains to be found. Researchers from diversified fields have attempted to design and fabricate novel biomaterials, aiming to find novel theranostic approaches for tissue engineering and regenerative medicine. Since no single biomaterial has been found to possess all the necessary characteristics for an ideal performance, over the years scientists have tried to develop composite biomaterials that complement and combine the beneficial properties of multiple materials into a superior matrix. Herein, we highlight the structural features and performance of various biomaterials and their application in regenerative medicine and for enhanced tissue engineering approaches.

Preparation and Characterization of Resorbable Bacterial Cellulose Membranes Treated by Electron Beam Irradiation for Guided Bone Regeneration

Bacterial cellulose (BC) is an excellent biomaterial with many medical applications. In this study, resorbable BC membranes were prepared for guided bone regeneration (GBR) using an irradiation technique for applications in the dental field. Electron beam irradiation (EI) increases biodegradation by severing the glucose bonds of BC. BC membranes irradiated at 100 kGy or 300 kGy were used to determine optimal electron beam doses. Electron beam irradiated BC membranes (EI-BCMs) were evaluated by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thermal gravimetric analysis (TGA), and using wet tensile strength measurements. In addition, in vitro cell studies were conducted in order to confirm the cytocompatibility of EI-BCMs. Cell viabilities of NIH3T3 cells on 100k and 300k EI-BCMs (100 kGy and 300 kGy irradiated BC membranes) were significantly greater than on NI-BCMs after 3 and 7 days (p < 0.05). Bone regeneration by EI-BCMs and their biodegradabilities were also evaluated using in vivo rat calvarial defect models for 4 and 8 weeks. Histometric results showed 100k EI-BCMs exhibited significantly larger new bone area (NBA; %) than 300k EI-BCMs at 8 weeks after implantation (p < 0.05). Mechanical, chemical, and biological analyses showed EI-BCMs effectively interacted with cells and promoted bone regeneration.

The Efficacy of Electron Beam Irradiated Bacterial Cellulose Membranes as Compared with Collagen Membranes on Guided Bone Regeneration in Peri-Implant Bone Defects

Bacterial cellulose (BC) is a natural polysaccharide produced by some bacteria, and consists of a linear polymer linked by β-(1,4) glycosidic bonds. BC has been developed as a material for tissue regeneration purposes. This study was conducted to evaluate the efficacy of resorbable electron beam irradiated BC membranes (EI-BCMs) for guided bone regeneration (GBR). The electron beam irradiation (EI) was introduced to control the biodegradability of BC for dental applications. EI-BCMs had higher porosity than collagen membranes (CMs), and had similar wet tensile strengths to CMs. NIH3T3 cell adhesion and proliferation on EI-BCMs were not significantly different from those on CMs (p > 0.05). Micro-computed tomography (μCT) and histometric analysis in peri-implant dehiscence defects of beagle dogs showed that EI-BCMs were non-significantly different from CMs in terms of new bone area (NBA; %), remaining bone substitute volume (RBA; %) and bone-to-implant contact (BIC; %) (p > 0.05). These results suggest resorbable EI-BCMs can be used as an alternative biomaterial for bone tissue regeneration.