A Review on Micro- to Nanocellulose Biopolymer Scaffold Forming for Tissue Engineering Applications

3D printing tissue-engineered scaffolds for auricular reconstruction

Congenital microtia is the most common cause of auricular defects, with a prevalence of approximately 5.18 per 10,000 individuals. Autologous rib cartilage grafting is the leading treatment modality at this stage of auricular reconstruction currently. However, harvesting rib cartilage may lead to donor site injuries, such as pneumothorax, postoperative pain, chest wall scarring, and deformity. Therefore, in the pursuit of better graft materials, biomaterial scaffolds with great histocompatibility, precise control of morphology, non-invasiveness properties are gradually becoming a new research hotspot in auricular reconstruction. This review collectively presents the exploit and application of 3D printing biomaterial scaffold in auricular reconstruction. Although the tissue-engineered ear still faces challenges before it can be widely applied to patients in clinical settings, and its long-term effects have yet to be evaluated, we aim to provide guidance for future research directions in 3D printing biomaterial scaffold for auricular reconstruction. This will ultimately benefit the translational and clinical application of cartilage tissue engineering and biomaterials in the treatment of auricular defects.

Aerogels based on Bacterial Nanocellulose and their Applications

Microbial cellulose stands out for its exceptional characteristics in the form of biofilms formed by highly interlocked fibrils, namely, bacterial nanocellulose (BNC). Concurrently, bio-based aerogels are finding uses in innovative materials owing to their lightweight, high surface area, physical, mechanical, and thermal properties. In particular, bio-based aerogels based on BNC offer significant opportunities as alternatives to synthetic or mineral counterparts. BNC aerogels are proposed for diverse applications, ranging from sensors to medical devices, as well as thermal and electroactive systems. Due to the fibrous nanostructure of BNC and the micro-porosity of BNC aerogels, these materials enable the creation of tailored and specialized designs. Herein, a comprehensive review of BNC-based aerogels, their attributes, hierarchical, and multiscale features are provided. Their potential across various disciplines is highlighted, emphasizing their biocompatibility and suitability for physical and chemical modification. BNC aerogels are shown as feasible options to advance material science and foster sustainable solutions through biotechnology.

3D Printing of Polysaccharide-Based Hydrogel Scaffolds for Tissue Engineering Applications: A Review

In tissue engineering, 3D printing represents a versatile technology employing inks to construct three-dimensional living structures, mimicking natural biological systems. This technology efficiently translates digital blueprints into highly reproducible 3D objects. Recent advances have expanded 3D printing applications, allowing for the fabrication of diverse anatomical components, including engineered functional tissues and organs. The development of printable inks, which incorporate macromolecules, enzymes, cells, and growth factors, is advancing with the aim of restoring damaged tissues and organs. Polysaccharides, recognized for their intrinsic resemblance to components of the extracellular matrix have garnered significant attention in the field of tissue engineering. This review explores diverse 3D printing techniques, outlining distinctive features that should characterize scaffolds used as ideal matrices in tissue engineering. A detailed investigation into the properties and roles of polysaccharides in tissue engineering is highlighted. The review also culminates in a profound exploration of 3D polysaccharide-based hydrogel applications, focusing on recent breakthroughs in regenerating different tissues such as skin, bone, cartilage, heart, nerve, vasculature, and skeletal muscle. It further addresses challenges and prospective directions in 3D printing hydrogels based on polysaccharides, paving the way for innovative research to fabricate functional tissues, enhancing patient care, and improving quality of life.

Nanocellulose-based hydrogels as versatile materials with interesting functional properties for tissue engineering applications

Tissue engineering has emerged as a remarkable field aiming to restore or replace damaged tissues through the use of biomimetic constructs. Among the diverse materials investigated for this purpose, nanocellulose-based hydrogels have garnered attention due to their intriguing biocompatibility, tunable mechanical properties, and sustainability. Over the past few years, numerous research works have been published focusing on the successful use of nanocellulose-based hydrogels as artificial extracellular matrices for regenerating various types of tissues. The review emphasizes the importance of tissue engineering, highlighting hydrogels as biomimetic scaffolds, and specifically focuses on the role of nanocellulose in composites that mimic the structures, properties, and functions of the native extracellular matrix for regenerating damaged tissues. It also summarizes the types of nanocellulose, as well as their structural, mechanical, and biological properties, and their contributions to enhancing the properties and characteristics of functional hydrogels for tissue engineering of skin, bone, cartilage, heart, nerves and blood vessels. Additionally, recent advancements in the application of nanocellulose-based hydrogels for tissue engineering have been evaluated and documented. The review also addresses the challenges encountered in their fabrication while exploring the potential future prospects of these hydrogel matrices for biomedical applications.

Revolutionizing Cancer Treatment: Biopolymer-Based Aerogels as Smart Platforms for Targeted Drug Delivery

Cancer stands as a leading cause of global mortality, with chemotherapy being a pivotal treatment approach, either alone or in conjunction with other therapies. The primary goal of these therapies is to inhibit the growth of cancer cells specifically, while minimizing harm to healthy dividing cells. Conventional treatments, often causing patient discomfort due to side effects, have led researchers to explore innovative, targeted cancer cell therapies. Thus, biopolymer-based aerogels emerge as innovative platforms, showcasing unique properties that respond intelligently to diverse stimuli. This responsiveness enables precise control over the release of anticancer drugs, enhancing therapeutic outcomes. The significance of these aerogels lies in their ability to offer targeted drug delivery with increased efficacy, biocompatibility, and a high drug payload. In this comprehensive review, the author discuss the role of biopolymer-based aerogels as an emerging functionalized platforms in anticancer drug delivery. The review addresses the unique properties of biopolymer-based aerogels showing their smart behavior in responding to different stimuli including temperature, pH, magnetic and redox potential to control anticancer drug release. Finally, the review discusses the application of different biopolymer-based aerogel in delivering different anticancer drugs and also discusses the potential of these platforms in gene delivery applications.

Nanocellulose-Based Hybrid Scaffolds for Skin and Bone Tissue Engineering: A 10-Year Overview

Cellulose, the most abundant polymer on Earth, has been widely utilized in its nanoform due to its excellent properties, finding applications across various scientific fields. As the demand for nanocellulose continues to rise and its ease of use becomes apparent, there has been a significant increase in research publications centered on this biomaterial. Nanocellulose, in its different forms, has shown tremendous promise as a tissue engineered scaffold for regeneration and repair. Particularly, nanocellulose-based composites and scaffolds have emerged as highly demanding materials for both soft and hard tissue engineering. Medical practitioners have traditionally relied on collagen and its analogue, gelatin, for treating tissue damage. However, the limited mechanical strength of these biopolymers restricts their direct use in various applications. This issue can be overcome by making hybrids of these biopolymers with nanocellulose. This review presents a comprehensive analysis of the recent and most relevant publications focusing on hybrid composites of collagen and gelatin with a specific emphasis on their combination with nanocellulose. While bone and skin tissue engineering represents two areas where a majority of researchers are concentrating their efforts, this review highlights the use of nanocellulose-based hybrids in these contexts.

Graph Network-Based Simulation of Multicellular Dynamics Driven by Concentrated Polymer Brush-Modified Cellulose Nanofibers

Manipulating the three-dimensional (3D) structures of cells is important for facilitating to repair or regenerate tissues. A self-assembly system of cells with cellulose nanofibers (CNFs) and concentrated polymer brushes (CPBs) has been developed to fabricate various cell 3D structures. To further generate tissues at an implantable level, it is necessary to carry out a large number of experiments using different cell culture conditions and material properties; however this is practically intractable. To address this issue, we present a graph-neural network-based simulator (GNS) that can be trained by using assembly process images to predict the assembly status of future time steps. A total of 24 (25 steps) time-series images were recorded (four repeats for each of six different conditions), and each image was transformed into a graph by regarding the cells as nodes and the connecting neighboring cells as edges. Using the obtained data, the performances of the GNS were examined under three scenarios (i.e., changing a pair of the training and testing data) to verify the possibility of using the GNS as a predictor for further time steps. It was confirmed that the GNS could reasonably reproduce the assembly process, even under the toughest scenario, in which the experimental conditions differed between the training and testing data. Practically, this means that the GNS trained by the first 24 h images could predict the cell types obtained 3 weeks later. This result could reduce the number of experiments required to find the optimal conditions for generating cells with desired 3D structures. Ultimately, our approach could accelerate progress in regenerative medicine.

A state-of-the-art review on plant-derived cellulose-based green hydrogels and their multifunctional role in advanced biomedical applications

The most prevalent carbohydrate on Earth is cellulose, a polysaccharide composed of glucose units that may be found in diverse sources, such as cell walls of wood and plants and some bacterial and algal species. The inherent availability of this versatile material provides a natural pathway for exploring and identifying novel uses. This study comprehensively analyzes cellulose and its derivatives, exploring their structural and biochemical features and assessing their wide-ranging applications in tissue fabrication, surgical dressings, and pharmaceutical delivery systems. The use of diverse cellulose particles as fundamental components gives rise to materials with distinct microstructures and characteristics, fulfilling the requirements of various biological applications. Although cellulose boasts substantial potential across various sectors, its exploration has predominantly unfolded within industrial realms, leaving the biomedical domain somewhat overlooked in its initial stages. This investigation, therefore, endeavors to shed light on the contemporary strides made in synthesizing cellulose and its derivatives. These innovative techniques give rise to distinctive attributes, presenting a treasure trove of advantages for their compelling integration into the intricate tapestry of biomedical applications.

Revolutionizing Wound Healing: Exploring Scarless Solutions through Drug Delivery Innovations

Human skin is the largest organ and outermost surface of the human body, and due to the continuous exposure to various challenges, it is prone to develop injuries, customarily known as wounds. Although various tissue engineering strategies and bioactive wound matrices have been employed to speed up wound healing, scarring remains a significant challenge. The wound environment is harsh due to the presence of degradative enzymes and elevated pH levels, and the physiological processes involved in tissue regeneration operate on distinct time scales. Therefore, there is a need for effective drug delivery systems (DDSs) to address these issues. The objective of this review is to provide a comprehensive exposition of the mechanisms underlying the skin healing process, the factors and materials used in engineering DDSs, and the different DDSs used in wound care. Furthermore, this investigation will delve into the examination of emergent technologies and potential avenues for enhancing the efficacy of wound care devices.

3D-Printed Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-Cellulose-Based Scaffolds for Biomedical Applications

While biomaterials have become indispensable for a wide range of tissue repair strategies, second removal procedures oftentimes needed in the case of non-bio-based and non-bioresorbable scaffolds are associated with significant drawbacks not only for the patient, including the risk of infection, impaired healing, or tissue damage, but also for the healthcare system in terms of cost and resources. New biopolymers are increasingly being investigated in the field of tissue regeneration, but their widespread use is still hampered by limitations regarding mechanical, biological, and functional performance when compared to traditional materials. Therefore, a common strategy to tune and broaden the final properties of biopolymers is through the effect of different reinforcing agents. This research work focused on the fabrication and characterization of a bio-based and bioresorbable composite material obtained by compounding a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) matrix with acetylated cellulose nanocrystals (CNCs). The developed biocomposite was further processed to obtain three-dimensional scaffolds by additive manufacturing (AM). The 3D printability of the PHBH-CNC biocomposites was demonstrated by realizing different scaffold geometries, and the results of in vitro cell viability studies provided a clear indication of the cytocompatibility of the biocomposites. Moreover, the CNC content proved to be an important parameter in tuning the different functional properties of the scaffolds. It was demonstrated that the water affinity, surface roughness, and in vitro degradability rate of biocomposites increase with increasing CNC content. Therefore, this tailoring effect of CNC can expand the potential field of use of the PHBH biopolymer, making it an attractive candidate for a variety of tissue engineering applications.

Biological Macromolecule-Based Scaffolds for Urethra Reconstruction

Urethral reconstruction strategies are limited with many associated drawbacks. In this context, the main challenge is the unavailability of a suitable tissue that can endure urine exposure. However, most of the used tissues in clinical practices are non-specialized grafts that finally fail to prevent urine leakage. Tissue engineering has offered novel solutions to address this dilemma. In this technology, scaffolding biomaterials characteristics are of prime importance. Biological macromolecules are naturally derived polymers that have been extensively studied for various tissue engineering applications. This review discusses the recent advances, applications, and challenges of biological macromolecule-based scaffolds in urethral reconstruction.

Nanostructured Bioaerogels as a Potential Solution for Particulate Matter Pollution

Particulate matter (PM) pollution is a significant environmental and public health issue globally. Exposure to high levels of PM, especially fine particles, can have severe health consequences. These particles can come from a variety of sources, including natural events like dust storms and wildfires, as well as human activities such as industrial processes and transportation. Although an extensive development in air filtration techniques has been made in the past few years, fine particulate matter still poses a serios and dangerous threat to human health and to our environment. Conventional air filters are fabricated from non-biodegradable and non-ecofriendly materials which can cause further environmental pollution as a result of their excessive use. Nanostructured biopolymer aerogels have shown great promise in the field of particulate matter removal. Their unique properties, renewable nature, and potential for customization make them attractive materials for air pollution control. In the present review, we discuss the meaning, properties, and advantages of nanostructured aerogels and their potential in particulate matter removal. Particulate matter pollution, types and sources of particulate matter, health effect, environmental effect, and the challenges facing scientists in particulate matter removal are also discussed in the present review. Finally, we present the most recent advances in using nanostructured bioaerogels in the removal of different types of particulate matter and discuss the challenges that we face in these applications.

An introductory review on advanced multifunctional materials

This review summarizes the applications of some of the advanced materials. It included the synthesis of several nanoparticles such as metal oxide nanoparticles (e.g., Fe₃O₄, ZnO, ZrOSO₄, MoO_3-x, CuO, AgFeO₂, Co₃O₄, CeO₂, SiO₂, and CuFeO₂); metal hydroxide nanosheets (e.g., Zn₅(OH)₈(NO₃)₂·2H₂O, Zn(OH)(NO₃)·H₂O, and Zn₅(OH)₈(NO₃)₂); metallic nanoparticles (Ag, Au, Pd, and Pt); carbon-based nanomaterials (graphene, graphene oxide (GO), graphitic carbon nitride (g-C₃N₄), and carbon dots (CDs)); biopolymers (cellulose, nanocellulose, TEMPO-oxidized cellulose nanofibers (TOCNFs), and chitosan); organic polymers (e.g. covalent-organic frameworks (COFs)); and hybrid materials (e.g. metal-organic frameworks (MOFs)). Most of these materials were applied in several fields such as environmental-based technologies (e.g., water remediation, air purification, gas storage), energy (production of hydrogen, dimethyl ether, solar cells, and supercapacitors), and biomedical sectors (sensing, biosensing, cancer therapy, and drug delivery). They can be used as efficient adsorbents and catalysts to remove emerging contaminants e.g., inorganic (i.e., heavy metals) and organic (e.g., dyes, antibiotics, pesticides, and oils in water via adsorption. They can be also used as catalysts for catalytic degradation reactions such as redox reactions of pollutants. They can be used as filters for air purification by capturing carbon dioxide (CO₂) and volatile organic compounds (VOCs). They can be used for hydrogen production via water splitting, alcohol oxidation, and hydrolysis of NaBH₄. Nanomedicine for some of these materials was also included being an effective agent as an antibacterial, nanocarrier for drug delivery, and probe for biosensing.

Nanofiber Scaffolds as Drug Delivery Systems Promoting Wound Healing

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol-gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems.

Cellulose and Lignin-Derived Scaffold and Their Biological Application in Tissue Engineering, Drug Delivery, and Wound Healing: A Review

The goal of tissue engineering is to repair and regenerate diseased and damaged tissues and organs with functional and biocompatible materials that mimic native and original tissues which leads to maintaining and improvement of tissue function. Lignin and cellulose are the most abundant polymers in nature and have many applications in industry. Moreover, recently the physicochemical behaviors of lignin and cellulose, including biocompatibility, biodegradability, and mechanical properties, have been used in diverse biological applications ranging from drug delivery to tissue engineering. To assess these aims, this review gives an overview and comprehensive knowledge and highlights the origin and applications of lignin and cellulose-derived scaffolds in different tissue engineering and other biological applications. Finally, the challenges for future development using lignin and cellulose are also included. Plant-based tissue engineering is a promising technology for progressing areas in biomedicine, regenerative medicine, and nanomedicine, with much research focused on the development of newer material scaffolds with individual specific features to make functional and biocompatible tissues and organs for medical applications.

The Fabrication of Gelatin-Elastin-Nanocellulose Composite Bioscaffold as a Potential Acellular Skin Substitute

Gelatin usage in scaffold fabrication is limited due to its lack of enzymatic and thermal resistance, as well as its mechanical weakness. Hence, gelatin requires crosslinking and reinforcement with other materials. This study aimed to fabricate and characterise composite scaffolds composed of gelatin, elastin, and cellulose nanocrystals (CNC) and crosslinked with genipin. The scaffolds were fabricated using the freeze-drying method. The composite scaffolds were composed of different concentrations of CNC, whereas scaffolds made of pure gelatin and a gelatin-elastin mixture served as controls. The physicochemical and mechanical properties of the scaffolds, and their cellular biocompatibility with human dermal fibroblasts (HDF), were evaluated. The composite scaffolds demonstrated higher porosity and swelling capacity and improved enzymatic resistance compared to the controls. Although the group with 0.5% (w/v) CNC recorded the highest pore size homogeneity, the diameters of most of the pores in the composite scaffolds ranged from 100 to 200 μm, which is sufficient for cell migration. Tensile strength analysis revealed that increasing the CNC concentration reduced the scaffolds' stiffness. Chemical analyses revealed that despite chemical and structural alterations, both elastin and CNC were integrated into the gelatin scaffold. HDF cultured on the scaffolds expressed collagen type I and α-SMA proteins, indicating the scaffolds' biocompatibility with HDF. Overall, the addition of elastin and CNC improved the properties of gelatin-based scaffolds. The composite scaffolds are promising candidates for an acellular skin substitute.

Valorization of nano-based lignocellulosic derivatives to procure commercially significant value-added products for biomedical applications

Biowaste, produced from nature, is preferred to be a good source of carbon and ligninolytic machinery for many microorganisms. They are complex biopolymers composed of lignin, cellulose, and hemicellulose traces. This biomass can be depolymerized to its nano-dimensions to gain exceptional properties useful in the field of cosmetics, pharmaceuticals, high-strength materials, etc. Nano-sized biomass derivatives overcome the inherent drawbacks of the parent material and offer promises as a potential material for a wide range of applications with their unique traits such as low-toxicity, biocompatibility, biodegradability and environmentally friendly nature with versatility. This review focuses on the production of value-added products feasible from nanocellulose, nano lignin, and xylan nanoparticles which is quite a novel study of its kind. Dawn of nanotechnology has converted bio waste by-products (hemicellulose and lignin) into useful precursors for many commercial products. Nano-cellulose has been employed in the fields of electronics, cosmetics, drug delivery, scaffolds, fillers, packaging, and engineering structures. Xylan nanoparticles and nano lignin have numerous applications as stabilizers, additives, textiles, adhesives, emulsifiers, and prodrugs for many polyphenols with an encapsulation efficiency of 50%. This study will support the potential development of composites for emerging applications in all aspects of interest and open up novel paths for multifunctional biomaterials in nano-dimensions for cosmetic, drug carrier, and clinical applications.

Toxicological Assessment of Cellulose Nanomaterials: Oral Exposure

Cellulose nanomaterials (CNMs) have emerged recently as an important group of sustainable bio-based nanomaterials (NMs) with potential applications in multiple sectors, including the food, food packaging, and biomedical fields. The widening of these applications leads to increased human oral exposure to these NMs and, potentially, to adverse health outcomes. Presently, the potential hazards regarding oral exposure to CNMs are insufficiently characterised. There is a need to understand and manage the potential adverse effects that might result from the ingestion of CNMs before products using CNMs reach commercialisation. This work reviews the potential applications of CNMs in the food and biomedical sectors along with the existing toxicological in vitro and in vivo studies, while also identifying current knowledge gaps. Relevant considerations when performing toxicological studies following oral exposure to CNMs are highlighted. An increasing number of studies have been published in the last years, overall showing that ingested CNMs are not toxic to the gastrointestinal tract (GIT), suggestive of the biocompatibility of the majority of the tested CNMs. However, in vitro and in vivo genotoxicity studies, as well as long-term carcinogenic or reproductive toxicity studies, are not yet available. These studies are needed to support a wider use of CNMs in applications that can lead to human oral ingestion, thereby promoting a safe and sustainable-by-design approach.

Recent Advances in Cellulose-Based Hydrogels for Tissue Engineering Applications

In recent years, cellulose has attracted much attention because of its excellent properties, such as its hydrophilicity, mechanical properties, biodegradability, biocompatibility, low cost and low toxicity. In addition, cellulose and its derivatives contain abundant hydrophilic functional groups (such as hydroxyl, carboxyl and aldehyde groups), which are good raw materials for synthesizing biocompatible hydrogels. In this paper, the application prospects of cellulose and its derivatives-based hydrogels in biomedical tissue engineering are summarized and discussed through the analysis of recent research. Firstly, we discuss the structure and properties of cellulose, nano celluloses (NC) from different sources (including cellulose nanocrystals (CNC), cellulose nanofibrils (CNF) and bacterial nano celluloses (BNC)) and cellulose derivatives (including cellulose ethers and cellulose esters) obtained by different modification methods. Then, the properties and preparation methods of physical and chemical cellulose hydrogels are described, respectively. The application of cellulose-based hydrogels as a tissue engineering scaffold (skin, bone and cartilage) in the biomedical field is introduced. Finally, the challenges and prospects of cellulose-based hydrogels in tissue engineering are summarized.

An Electroconductive, Thermosensitive, and Injectable Chitosan/Pluronic/Gold-Decorated Cellulose Nanofiber Hydrogel as an Efficient Carrier for Regeneration of Cardiac Tissue

Myocardial infarction is a major cause of death worldwide and remains a social and healthcare burden. Injectable hydrogels with the ability to locally deliver drugs or cells to the damaged area can revolutionize the treatment of heart diseases. Herein, we formulate a thermo-responsive and injectable hydrogel based on conjugated chitosan/poloxamers for cardiac repair. To tailor the mechanical properties and electrical signal transmission, gold nanoparticles (AuNPs) with an average diameter of 50 nm were physically bonded to oxidized bacterial nanocellulose fibers (OBC) and added to the thermosensitive hydrogel at the ratio of 1% w/v. The prepared hydrogels have a porous structure with open pore channels in the range of 50−200 µm. Shear rate sweep measurements demonstrate a reversible phase transition from sol to gel with increasing temperature and a gelation time of 5 min. The hydrogels show a shear-thinning behavior with a shear modulus ranging from 1 to 12 kPa dependent on gold concentration. Electrical conductivity studies reveal that the conductance of the polymer matrix is 6 × 10−2 S/m at 75 mM Au. In vitro cytocompatibility assays by H9C2 cells show high biocompatibility (cell viability of >90% after 72 h incubation) with good cell adhesion. In conclusion, the developed nanocomposite hydrogel has great potential for use as an injectable biomaterial for cardiac tissue regeneration.

Advances in Cellulose-Based Hydrogels for Biomedical Engineering: A Review Summary

In recent years, hydrogel-based research in biomedical engineering has attracted more attention. Cellulose-based hydrogels have become a research hotspot in the field of functional materials because of their outstanding characteristics such as excellent flexibility, stimulus-response, biocompatibility, and degradability. In addition, cellulose-based hydrogel materials exhibit excellent mechanical properties and designable functions through different preparation methods and structure designs, demonstrating huge development potential. In this review, we have systematically summarized sources and types of cellulose and the formation mechanism of the hydrogel. We have reviewed and discussed the recent progress in the development of cellulose-based hydrogels and introduced their applications such as ionic conduction, thermal insulation, and drug delivery. Also, we analyzed and highlighted the trends and opportunities for the further development of cellulose-based hydrogels as emerging materials in the future.

Cellulose-Based Nanomaterials Advance Biomedicine: A Review

There are various biomaterials, but none fulfills all requirements. Cellulose biopolymers have advanced biomedicine to satisfy high market demand and circumvent many ecological concerns. This review aims to present an overview of cellulose knowledge and technical biomedical applications such as antibacterial agents, antifouling, wound healing, drug delivery, tissue engineering, and bone regeneration. It includes an extensive bibliography of recent research findings from fundamental and applied investigations. Cellulose-based materials are tailorable to obtain suitable chemical, mechanical, and physical properties required for biomedical applications. The chemical structure of cellulose allows modifications and simple conjugation with several materials, including nanoparticles, without tedious efforts. They render the applications cheap, biocompatible, biodegradable, and easy to shape and process.

Green Polymer Nanocomposites for Skin Tissue Engineering

Fabrication of an appropriate skin scaffold needs to meet several standards related to the mechanical and biological properties. Fully natural/green scaffolds with acceptable biodegradability, biocompatibility, and physiological properties quite often suffer from poor mechanical properties. Therefore, for appropriate skin tissue engineering and to mimic the real functions, we need to use synthetic polymers and/or additives as complements to green polymers. Green nanocomposites (either nanoscale natural macromolecules or biopolymers containing nanoparticles) are a class of scaffolds with acceptable biomedical properties window (drug delivery and cardiac, nerve, bone, cartilage as well as skin tissue engineering), enabling one to achieve the required level of skin regeneration and wound healing. In this review, we have collected, summarized, screened, analyzed, and interpreted the properties of green nanocomposites used in skin tissue engineering and wound dressing. We particularly emphasize the mechanical and biological properties that skin cells need to meet when seeded on the scaffold. In this regard, the latest state of the art studies directed at fabrication of skin tissue and bionanocomposites as well as their mechanistic features are discussed, whereas some unspoken complexities and challenges for future developments are highlighted.

Cellulosic-Based Conductive Hydrogels for Electro-Active Tissues: A Review Summary

The use of hydrogel in tissue engineering is not entirely new. In the last six decades, researchers have used hydrogel to develop artificial organs and tissue for the diagnosis of real-life problems and research purposes. Trial and error dominated the first forty years of tissue generation. Nowadays, biomaterials research is constantly progressing in the direction of new materials with expanded capabilities to better meet the current needs. Knowing the biological phenomenon at the interaction among materials and the human body has promoted the development of smart bio-inert and bio-active polymeric materials or devices as a result of vigorous and consistent research. Hydrogels can be tailored to contain properties such as softness, porosity, adequate strength, biodegradability, and a suitable surface for adhesion; they are ideal for use as a scaffold to provide support for cellular attachment and control tissue shapes. Perhaps electrical conductivity in hydrogel polymers promotes the interaction of electrical signals among artificial neurons and simulates the physiological microenvironment of electro-active tissues. This paper presents a review of the current state-of-the-art related to the complete process of conductive hydrogel manufacturing for tissue engineering from cellulosic materials. The essential properties required by hydrogel for electro-active-tissue regeneration are explored after a short overview of hydrogel classification and manufacturing methods. To prepare hydrogel from cellulose, the base material, cellulose, is first synthesized from plant fibers or generated from bacteria, fungi, or animals. The natural chemistry of cellulose and its derivatives in the fabrication of hydrogels is briefly discussed. Thereafter, the current scenario and latest developments of cellulose-based conductive hydrogels for tissue engineering are reviewed with an illustration from the literature. Finally, the pro and cons of conductive hydrogels for tissue engineering are indicated.

Recent Progress in Modification Strategies of Nanocellulose-Based Aerogels for Oil Absorption Application

Oil spills and oily wastewater have become a major environmental problem in recent years, directly impacting the environment and biodiversity. Several techniques have been developed to solve this problem, including biological degradation, chemicals, controlled burning, physical absorption and membrane separation. Recently, biopolymeric aerogels have been proposed as a green solution for this problem, and they possess superior selective oil absorption capacity compared with other approaches. Several modification strategies have been applied to nanocellulose-based aerogel to enhance its poor hydrophobicity, increase its oil absorption capacity, improve its selectivity of oils and make it a compressible and elastic magnetically responsive aerogel, which will ease its recovery after use. This review presents an introduction to nanocellulose-based aerogel and its fabrication approaches. Different applications of nanocellulose aerogel in environmental, medical and industrial fields are presented. Different strategies for the modification of nanocellulose-based aerogel are critically discussed in this review, presenting the most recent works in terms of enhancing the aerogel performance in oil absorption in addition to the potential of these materials in near future.

Chemical Stabilization behind Cardamom Pickering Emulsion Using Nanocellulose

Cardamom essential oil (EO) is a rare oil of high scientific and economic interest due to its biofunctionality. This work aims to stabilize the EO by Pickering emulsions with nanocellulose, in the form of nanocrystals (CNC) or nanofibers (CNF), and to investigate the stability and chemical and physical interactions involved in the process. The emulsions were characterized by droplet size, morphology, stability, surface charges, Fourier transform infrared spectroscopy, FT-Raman, nuclear magnetic resonance, and scanning electron microscopy. Stable emulsions were prepared with cellulose morphologies and CNCs resulted in a 34% creaming index, while CNFs do not show instability. Emulsions indicate a possible interaction between nanocellulose, α-terpinyl acetate, and 1,8-cineole active essential oil compounds, where α-terpinyl acetate would be inside the drop and 1,8-cineole is more available to interact with cellulose. The interaction intensity depended on the morphology, which might be due to the nanocellulose’s self-assembly around oil droplets and influence on oil availability and future application. This work provides a systematic picture of cardamomum derived essential oil Pickering emulsion containing nanocellulose stabilizers’ formation and stability, which can further be extended to other value-added oils and can be an alternative for the delivery of cardamom essential oil for biomedical, food, cosmetics, and other industries.

Extraction and Isolation of Cellulose Nanofibers from Carpet Wastes Using Supercritical Carbon Dioxide Approach

Cellulose nanofibers (CNFs) are the most advanced bio-nanomaterial utilized in various applications due to their unique physical and structural properties, renewability, biodegradability, and biocompatibility. It has been isolated from diverse sources including plants as well as textile wastes using different isolation techniques, such as acid hydrolysis, high-intensity ultrasonication, and steam explosion process. Here, we planned to extract and isolate CNFs from carpet wastes using a supercritical carbon dioxide (Sc.CO₂) treatment approach. The mechanism of defibrillation and defragmentation caused by Sc.CO₂ treatment was also explained. The morphological analysis of bleached fibers showed that Sc.CO₂ treatment induced several longitudinal fractions along with each fiber due to the supercritical condition of temperature and pressure. Such conditions removed th fiber’s impurities and produced more fragile fibers compared to untreated samples. The particle size analysis and Transmission Electron Microscopes (TEM) confirm the effect of Sc.CO₂ treatment. The average fiber length and diameter of Sc.CO₂ treated CNFs were 53.72 and 7.14 nm, respectively. In comparison, untreated samples had longer fiber length and diameter (302.87 and 97.93 nm). The Sc.CO₂-treated CNFs also had significantly higher thermal stability by more than 27% and zeta potential value of −38.9± 5.1 mV, compared to untreated CNFs (−33.1 ± 3.0 mV). The vibrational band frequency and chemical composition analysis data confirm the presence of cellulose function groups without any contamination with lignin and hemicellulose. The Sc.CO₂ treatment method is a green approach for enhancing the isolation yield of CNFs from carpet wastes and produce better quality nanocellulose for advanced applications.

Silica-Bacterial Cellulose Composite Aerogel Fibers with Excellent Mechanical Properties from Sodium Silicate Precursor

Forming fibers for fabric insulation is difficult using aerogels, which have excellent thermal insulation performance but poor mechanical properties. A previous study proposed a novel method that could effectively improve the mechanical properties of aerogels and make them into fibers for use in fabric insulation. In this study, composite aerogel fibers (CAFs) with excellent mechanical properties and thermal insulation performance were prepared using a streamlined method. The wet bacterial cellulose (BC) matrix without freeze-drying directly was immersed in an inorganic precursor (silicate) solution, followed by initiating in situ sol-gel reaction under the action of acidic catalyst after secondary shaping. Finally, after surface modification and ambient drying of the wet composite gel, CAFs were obtained. The CAFs prepared by the simplified method still had favorable mechanical properties (tensile strength of 4.5 MPa) and excellent thermal insulation properties under extreme conditions (220 °C and −60 °C). In particular, compared with previous work, the presented CAFs preparation process is simpler and more environmentally friendly. In addition, the experimental costs were reduced. Furthermore, the obtained CAFs had high specific surface area (671.3 m²/g), excellent hydrophobicity, and low density (≤0.154 g/cm³). This streamlined method was proposed to prepare aerogel fibers with excellent performance to meet the requirements of wearable applications.

Preparation and Characterization of Nanocellulose/Chitosan Aerogel Scaffolds Using Chemical-Free Approach

Biopolymer-based aerogels are open three-dimensional porous materials that are characterized by outstanding properties, such as a low density, high porosity and high surface area, in addition to their biocompatibility and non-cytotoxicity. Here we fabricated pure and binary blended aerogels from cellulose nanofibers (CNFs) and chitosan (CS), using a chemical-free approach that consists of high-pressure homogenization and freeze-drying. The prepared aerogels showed a different porosity and density, depending on the material and mixing ratio. The porosity and density of the aerogels ranged from 99.1 to 90.8% and from 0.0081 to 0.141 g/cm³, respectively. Pure CNFs aerogel had the highest porosity and lightest density, but it showed poor mechanical properties and a high water absorption capacity. Mixing CS with CNFs significantly enhance the mechanical properties and reduce its water uptake. The two investigated ratios of aerogel blends had superior mechanical and thermal properties over the single-material aerogels, in addition to reduced water uptake and 2-log antibacterial activity. This green fabrication and chemical-free approach could have great potential in the preparation of biopolymeric scaffolds for different biomedical applications, such as tissue-engineering scaffolds.

Functional survey of decellularized tissues transplantation for infertile females

Numbers of women worldwide face infertility, which will have a significant impact on a couple's life. As a result, assisting with the treatment of these individuals is seen as a critical step. Successful births following uterus and ovary donation have been reported in recent. When immunosuppressive drugs are used in patients who receive donated tissues, there are always problems with the drugs' side effects. In recent years, tissue engineering has mainly been successful in treating infertility using decellularization techniques. Engineered uterus and ovary prevent immunological reactions and do not require immunosuppressive drugs. The most important aspect of using decellularized tissue is its proper function after transplantation. These tissues must be able to produce follicles, secrete hormones and cause pregnancy. This study aimed to investigate research on decellularized tissues and transplanted into the female reproductive system. In this study, just tissues that, after transplantation, have the proper function for fertility were investigated.

Preparation, Marriage Chemistry and Applications of Graphene Quantum Dots-Nanocellulose Composite: A Brief Review

Graphene quantum dots (GQDs) are zero-dimensional carbon-based materials, while nanocellulose is a nanomaterial that can be derived from naturally occurring cellulose polymers or renewable biomass resources. The unique geometrical, biocompatible and biodegradable properties of both these remarkable nanomaterials have caught the attention of the scientific community in terms of fundamental research aimed at advancing technology. This study reviews the preparation, marriage chemistry and applications of GQDs-nanocellulose composites. The preparation of these composites can be achieved via rapid and simple solution mixing containing known concentration of nanomaterial with a pre-defined composition ratio in a neutral pH medium. They can also be incorporated into other matrices or drop-casted onto substrates, depending on the intended application. Additionally, combining GQDs and nanocellulose has proven to impart new hybrid nanomaterials with excellent performance as well as surface functionality and, therefore, a plethora of applications. Potential applications for GQDs-nanocellulose composites include sensing or, for analytical purposes, injectable 3D printing materials, supercapacitors and light-emitting diodes. This review unlocks windows of research opportunities for GQDs-nanocellulose composites and pave the way for the synthesis and application of more innovative hybrid nanomaterials.

Recent developments in polysaccharide-based electrospun nanofibers for environmental applications

Electrospinning has become an inevitable approach to produce nanofibrous structures for diverse environmental applications. Polysaccharides, due to their variety of types, biobased origins, and eco-friendly, and renewable nature are wonderful materials for the said purpose. The present review discusses the electrospinning process, the parameters involved in the formation of electrospun nanofibers in general, and the polysaccharides in specific. The selection of materials to be electrospun depends on the processing conditions and properties deemed desirable for specific applications. Thereby, the conditions to electrospun polysaccharides-based nanofibers have been focused on for possible environmental applications including air filtration, water treatment, antimicrobial treatment, environmental sensing, and so forth. The polysaccharide-based electrospun membranes, for instance, due to their active adsorption sites could find significant potential for contaminants removal from the aqueous systems. The study also gives some recommendations to overcome any shortcomings faced during the electrospinning and environmental applications of polysaccharide-based matrices.

Additive Manufacturing of Biopolymers for Tissue Engineering and Regenerative Medicine: An Overview, Potential Applications, Advancements, and Trends

As a technique of producing fabric engineering scaffolds, three-dimensional (3D) printing has tremendous possibilities. 3D printing applications are restricted to a wide range of biomaterials in the field of regenerative medicine and tissue engineering. Due to their biocompatibility, bioactiveness, and biodegradability, biopolymers such as collagen, alginate, silk fibroin, chitosan, alginate, cellulose, and starch are used in a variety of fields, including the food, biomedical, regeneration, agriculture, packaging, and pharmaceutical industries. The benefits of producing 3D-printed scaffolds are many, including the capacity to produce complicated geometries, porosity, and multicell coculture and to take growth factors into account. In particular, the additional production of biopolymers offers new options to produce 3D structures and materials with specialised patterns and properties. In the realm of tissue engineering and regenerative medicine (TERM), important progress has been accomplished; now, several state-of-the-art techniques are used to produce porous scaffolds for organ or tissue regeneration to be suited for tissue technology. Natural biopolymeric materials are often better suited for designing and manufacturing healing equipment than temporary implants and tissue regeneration materials owing to its appropriate properties and biocompatibility. The review focuses on the additive manufacturing of biopolymers with significant changes, advancements, trends, and developments in regenerative medicine and tissue engineering with potential applications.

Supercritical Carbon Dioxide Isolation of Cellulose Nanofibre and Enhancement Properties in Biopolymer Composites

The physical properties, such as the fibre dimension and crystallinity, of cellulose nanofibre (CNF) are significant to its functional reinforcement ability in composites. This study used supercritical carbon dioxide as a fibre bundle defibrillation pretreatment for the isolation of CNF from bamboo, in order to enhance its physical properties. The isolated CNF was characterised through zeta potential, TEM, XRD, and FT-IR analysis. Commercial CNF was used as a reference to evaluate the effectiveness of the method. The physical, mechanical, thermal, and wettability properties of the bamboo and commercial CNF-reinforced PLA/chitin were also analysed. The TEM and FT-IR results showed the successful isolation of CNF from bamboo using this method, with good colloidal stability shown by the zeta potential results. The properties of the isolated bamboo CNF were similar to the commercial type. However, the fibre diameter distribution and the crystallinity index significantly differed between the bamboo and the commercial CNF. The bamboo CNF had a smaller fibre size and a higher crystallinity index than the commercial CNF. The results from the CNF-reinforced biocomposite showed that the physical, mechanical, thermal, and wettability properties were significantly different due to the variations in their fibre sizes and crystallinity indices. The properties of bamboo CNF biocomposites were significantly better than those of commercial CNF biocomposites. This indicates that the physical properties (fibre size and crystallinity) of an isolated CNF significantly affect its reinforcement ability in biocomposites. The physical properties of isolated CNFs are partly dependent on their source and production method, among other factors. These composites can be used for various industrial applications, including packaging.

Nanocellulose Production Using Ionic Liquids with Enzymatic Pretreatment

Nanocellulose has gained increasing attention during the past decade, which is related to its unique properties and wide application. In this paper, nanocellulose samples were produced via hydrolysis with ionic liquids (1-ethyl-3-methylimidazole acetate (EmimOAc) and 1-allyl-3-methylimidazolium chloride (AmimCl)) from microcrystalline celluloses (Avicel and Whatman) subjected to enzymatic pretreatment. The obtained material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). The results showed that the nanocellulose had a regular and spherical structure with diameters of 30-40 nm and exhibited lower crystallinity and thermal stability than the material obtained after hydrolysis with Trichoderma reesei enzymes. However, the enzyme-pretreated Avicel had a particle size of about 200 nm and a cellulose II structure. A two-step process involving enzyme pretreatment and hydrolysis with ionic liquids resulted in the production of nanocellulose. Moreover, the particle size of nanocellulose and its structure depend on the ionic liquid used.

AK, Olaiya NG, Iqbal MO, Jummaat F, A.K. AS, Adnan AS. Insights into the Role of Biopolymer Aerogel Scaffolds in Tissue Engineering and Regenerative Medicine

The global transplantation market size was valued at USD 8.4 billion in 2020 and is expected to grow at a compound annual growth rate of 11.5% over the forecast period. The increasing demand for tissue transplantation has inspired researchers to find alternative approaches for making artificial tissues and organs function. The unique physicochemical and biological properties of biopolymers and the attractive structural characteristics of aerogels such as extremely high porosity, ultra low-density, and high surface area make combining these materials of great interest in tissue scaffolding and regenerative medicine applications. Numerous biopolymer aerogel scaffolds have been used to regenerate skin, cartilage, bone, and even heart valves and blood vessels by growing desired cells together with the growth factor in tissue engineering scaffolds. This review focuses on the principle of tissue engineering and regenerative medicine and the role of biopolymer aerogel scaffolds in this field, going through the properties and the desirable characteristics of biopolymers and biopolymer tissue scaffolds in tissue engineering applications. The recent advances of using biopolymer aerogel scaffolds in the regeneration of skin, cartilage, bone, and heart valves are also discussed in the present review. Finally, we highlight the main challenges of biopolymer-based scaffolds and the prospects of using these materials in regenerative medicine.

P. S. AK, Oyekanmi AA, Gideon ON, Abdullah CK, Yahya EB, Alfatah T, Sabaruddin FA, Rahman AA. Cotton Wastes Functionalized Biomaterials from Micro to Nano: A Cleaner Approach for a Sustainable Environmental Application

The exponential increase in textile cotton wastes generation and the ineffective processing mechanism to mitigate its environmental impact by developing functional materials with unique properties for geotechnical applications, wastewater, packaging, and biomedical engineering have become emerging global concerns among researchers. A comprehensive study of a processed cotton fibres isolation technique and their applications are highlighted in this review. Surface modification of cotton wastes fibre increases the adsorption of dyes and heavy metals removal from wastewater. Cotton wastes fibres have demonstrated high adsorption capacity for the removal of recalcitrant pollutants in wastewater. Cotton wastes fibres have found remarkable application in slope amendments, reinforcement of expansive soils and building materials, and a proven source for isolation of cellulose nanocrystals (CNCs). Several research work on the use of cotton waste for functional application rather than disposal has been done. However, no review study has discussed the potentials of cotton wastes from source (Micro-Nano) to application. This review critically analyses novel isolation techniques of CNC from cotton wastes with an in-depth study of a parameter variation effect on their yield. Different pretreatment techniques and efficiency were discussed. From the analysis, chemical pretreatment is considered the most efficient extraction of CNCs from cotton wastes. The pretreatment strategies can suffer variation in process conditions, resulting in distortion in the extracted cellulose's crystallinity. Acid hydrolysis using sulfuric acid is the most used extraction process for cotton wastes-based CNC. A combined pretreatment process, such as sonication and hydrolysis, increases the crystallinity of cotton-based CNCs. The improvement of the reinforced matrix interface of textile fibres is required for improved packaging and biomedical applications for the sustainability of cotton-based CNCs.

Recent advances in 3D printing of nanocellulose: structure, preparation, and application prospects

Emerging cellulose nanomaterials extracted from agricultural biomasses have recently received extensive attention due to diminishing fossil resources. To further reduce the carbon footprints and wastage of valuable resources, additive manufacturing techniques of new nanocellulosic materials have been developed. Studies on the preparation and characterization of 3D-printable functional nanocellulosic materials have facilitated a deeper understanding into their desirable attributes such as high surface area, biocompatibility, and ease of functionalization. In this critical review, we compare and highlight the different methods of extracting nanocellulose from biorenewable resources and the strategies for transforming the obtained nanocellulose into nanocomposites with high 3D printability. Optimistic technical applications of 3D-printed nanocellulose in biomedical, electronics, and environmental fields are finally described and evaluated for future perspectives.

A, Adnan AS, Alqadhi AM, Abdullah CK, A.K. AS, Olaiya NG, Abdat M. The Role of Biopolymer-Based Materials in Obstetrics and Gynecology Applications: A Review

Biopolymers have gained tremendous attention in many daily life applications, including medical applications, in the past few years. Obstetrics and gynecology are two fields dealing with sensitive parts of the woman's body and her newborn baby, which are normally associated with many issues such as toxicity, infections, and even gene alterations. Medical professions that use screening, examination, pre, and post-operation materials should benefit from a better understanding of each type of material's characteristics, health, and even environmental effects. The underlying principles of biopolymer-based materials for different obstetric and gynecologic applications may discover various advantages and benefits of using such materials. This review presents the health impact of conventional polymer-based materials on pregnant women's health and highlights the potential use of biopolymers as a safer option. The recent works on utilizing different biopolymer-based materials in obstetric and gynecologic are presented in this review, which includes suture materials in obstetric and gynecologic surgeries, cosmetic and personal care products, vaginal health, and drug delivery; as well as a wound dressing and healing materials. This review highlights the main issues and challenges of biopolymers in obstetric and gynecologic applications.

Valorization of Gleditsia triacanthos Invasive Plant Cellulose Microfibers and Phenolic Compounds for Obtaining Multi-Functional Wound Dressings with Antimicrobial and Antioxidant Properties

Gleditsia triacanthos is an aggressive invasive species in Eastern Europe, producing a significant number of pods that could represent an inexhaustible resource of raw material for various applications. The aim of this study was to extract cellulose from the Gleditsia triacanthos pods, characterize it by spectrophotometric and UHPLC-DAD-ESI/MS analysis, and use it to fabricate a wound dressing that is multi-functionalized with phenolic compounds extracted from the leaves of the same species. The obtained cellulose microfibers (CM) were functionalized, lyophilized, and characterized by ATR-FTIR and SEM. The water absorption and retention capacity as well as the controlled release of phenolic compounds with antioxidant properties evaluated in temporal dynamics were also determined. The antimicrobial activity against reference and clinical multi-drug-resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae, Candida albicans, and Candida parapsilosis strains occurred immediately after the contact with the tested materials and was maintained for 24 h for all tested microbial strains. In conclusion, the multi-functionalized cellulose microfibers (MFCM) obtained from the reproductive organs of an invasive species can represent a promising alternative for the development of functional wound dressings with antioxidant and antimicrobial activity, as well as being a scalable example for designing cost-effective, circular bio-economy approaches to combat the accelerated spread of invasive species.

A Review on Revolutionary Natural Biopolymer-Based Aerogels for Antibacterial Delivery

A biopolymer-based aerogel has been developed to become one of the most potentially utilized materials in different biomedical applications. The biopolymer-based aerogel has unique physical, chemical, and mechanical properties and these properties are used in tissue engineering, biosensing, diagnostic, medical implant and drug delivery applications. Biocompatible and non-toxic biopolymers such as chitosan, cellulose and alginates have been used to deliver antibiotics, plants extract, essential oils and metallic nanoparticles. Antibacterial aerogels have been used in superficial and chronic wound healing as dressing sheets. This review critically analyses the utilization of biopolymer-based aerogels in antibacterial delivery. The analysis shows the relationship between their properties and their applications in the wound healing process. Furthermore, highlights of the potentials, challenges and proposition of the application of biopolymer-based aerogels is explored.