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Due to the intensification of global warming and the greenhouse effect, the exploration and research of sustainable sensors have become a research direction of people. Cellulose-based hydrogels, as a new kind of green material with strong plasticity, have become a popular material for sensor development. Due to the limited mechanical properties and poor compatibility of single-cellulose-based hydrogels, researchers have modified them to not only retain the original excellent properties of cellulose hydrogels, but also increase other properties, which has broadened the field of developing cellulose hydrogel sensors. From 2017 to 2020, cellulose-based hydrogel sensors were mainly used for biosensing applications, with a focus on the detection of biomolecules. Since then, researchers have increasingly turned their attention to pressure and strain sensors, especially those that are flexible and suitable for wearable devices. This paper introduces the modification of cellulose and cellulose-based hydrogels in detail, and lists the applications of modified cellulose-based hydrogels in different functional sensor directions, which provides different ideas for the application of modified cellulose-based hydrogels in the field of sensing, and proves that they have great potential in the field of sensing.

Bacterial cellulose (BC) as a never-dried biopolymer synthesized in abundance by Gluconacetobacter xylinus is in a pure form which requires no intensive processing to remove unwanted impurities and contaminants such as lignin, pectin and hemicellulose. In contrast to plant cellulose, BC, with several remarkable physical properties, can be grown to any desired shape and structure to meet the needs of different applications. BC has been commercialized as diet foods, filtration membranes, paper additives, and wound dressings. This review article presents an overview of BC structure, biosynthesis, applications, state-of-the-art advances in enhancing BC production, and its material properties through the investigations of genetic regulations, fermentation parameters, and bioreactor design. In addition, future prospects on its applications through chemical modification as a new biologically active derivative will be discussed.

Cellulose-based sorbents are promising materials for wastewater treatment due to their environmental friendliness, biodegradability, and high sorption capacity. This paper presents an overview of cellulose modification methods, including carboxylation, amination, oxidation, graphene, and plasma treatments, as well as combined approaches. Their effect on key physicochemical properties, such as porosity, morphology, and chemical stability, is considered. Examples from the literature confirm the effectiveness of modified cellulose sorbents in removing heavy metal ions and organic pollutants from wastewater. The analysis shows that combined methods allow for creating materials with improved characteristics that are resistant to extreme operating conditions. The main advantages and disadvantages of cellulose sorbents, as well as challenges associated with their scalability and cost-effectiveness, are discussed. The paper emphasizes the importance of further research to advance these materials as a key element of sustainable water treatment technologies.

Aliphatic polyesters/cellulose composites have attracted a lot attention due to the perspectives of their application in biomedicine and the production of disposable materials, food packaging, etc. Both aliphatic polyesters and cellulose are biocompatible and biodegradable polymers, which makes them highly promising for the production of “green” composite materials. However, the main challenge in obtaining composites with favorable properties is the poor compatibility of these polymers. Unlike cellulose, which is very hydrophilic, aliphatic polyesters exhibit strong hydrophobic properties. In recent times, the modification of cellulose micro- and nanomaterials is widely considered as a tool to enhance interfacial biocompatibility with aliphatic polyesters and, consequently, improve the properties of composites. This review summarizes the main types and properties of cellulose micro- and nanomaterials as well as aliphatic polyesters used to produce composites with cellulose. In addition, the methods for noncovalent and covalent modification of cellulose materials with small molecules, polymers and nanoparticles have been comprehensively overviewed and discussed. Composite fabrication techniques, as well as the effect of cellulose modification on the mechanical and thermal properties, rate of degradation, and biological compatibility have been also analyzed.

The effective and straight-forward modification of nanostructured celluloses under aqueous conditions or as “never-dried” materials is challenging. We report a silanization protocol in water using catalytic amounts of hydrogen chloride and then sodium hydroxide in a two-step protocol. The acidic step hydrolyzes the alkoxysilane to obtain water-soluble silanols and the subsequent addition of catalytic amounts of NaOH induces a covalent reaction between cellulose surficial hydroxyl groups and the respective silanols. The developed protocol enables the incorporation of vinyl, thiol, and azido groups onto cellulose fibers and cellulose nanofibrils. In contrast to conventional methods, no curing or solvent-exchange is necessary, thereby the functionalized celluloses remain never-dried, and no agglomeration or hornification occurs in the process. The successful modification was proven by solid state NMR, ATR-IR, and EDX spectroscopy. In addition, the covalent nature of this bonding was shown by gel permeation chromatography of polyethylene glycol grafted nanofibrils. By varying the amount of silane agents or the reaction time, the silane loading could be tuned up to an amount of 1.2 mmol/g. Multifunctional materials were obtained either by prior carboxymethylation and subsequent silanization; or by simultaneously incorporating both vinyl and azido groups. The protocol reported here is an easy, general, and straight-forward avenue for introduction of anchor groups onto the surface of never-dried celluloses, ready for click chemistry post-modification, to obtain multifunctional cellulose substrates for high-value applications.

Inappropriate discharge of industrial wastewater and household effluent has led to an accumulation of hazardous organic substances, oil and grease, heavy metal ions, dyes, and leftover pharmaceutical products in the aquatic environment. To mitigate the adverse effects of polluted water, various techniques have been implemented for physical, chemical, and biological wastewater treatments. In chemical wastewater treatments, utilizing polymers are among the most common pathways, in which cellulose-derived materials as one of the abundantly available lignocellulosic constituents have gained much interest for the applications. As environmental remediation agents, cellulose derivatives have great potential due to their biocompatibility, excellent mechanical properties, environmental friendliness, economic viability, low toxicity, and robustness. In a chemical wastewater treatment, cellulose derivatives can be valorized to various industrial applications, such as membrane technology, absorption and adsorption process, flocculant, a catalyst for chemical reaction, and disinfecting agent. In this review paper, various types of utilization methods of cellulose derivatives, ranging from nano, micro, and natural form in industrial wastewater and household effluent treatment, are extensively discussed. In addition, the cellulose performance in adsorption, filtration is also briefly elaborated and then compared with those of the conventional polymer-based materials, such as polyether sulfone (PES), Polyvinylidene fluoride (PVDF), and carbon nanofiber (CNF).Graphic abstract

New carriers for protein immobilization are objects of interest in various fields of biomedicine. Immobilization is a technique used to stabilize and provide physical support for biological micro- and macromolecules and whole cells. Special efforts have been made to develop new materials for protein immobilization that are non-toxic to both the body and the environment, inexpensive, readily available, and easy to modify. Currently, biodegradable and non-toxic polymers, including cellulose, are widely used for protein immobilization. Bacterial cellulose (BC) is a natural polymer with excellent biocompatibility, purity, high porosity, high water uptake capacity, non-immunogenicity, and ease of production and modification. BC is composed of glucose units and does not contain lignin or hemicellulose, which is an advantage allowing the avoidance of the chemical purification step before use. Recently, BC–protein composites have been developed as wound dressings, tissue engineering scaffolds, three-dimensional (3D) cell culture systems, drug delivery systems, and enzyme immobilization matrices. Proteins or peptides are often added to polymeric scaffolds to improve their biocompatibility and biological, physical–chemical, and mechanical properties. To broaden BC applications, various ex situ and in situ modifications of native BC are used to improve its properties for a specific application. In vivo studies showed that several BC–protein composites exhibited excellent biocompatibility, demonstrated prolonged treatment time, and increased the survival of animals. Today, there are several patents and commercial BC-based composites for wounds and vascular grafts. Therefore, further research on BC–protein composites has great prospects. This review focuses on the major advances in protein immobilization on BC for biomedical applications.

A large amount of agricultural waste was used to prepare cellulose (Cel) and then the surface was modified with PEI (Cel-PEI) using the microwave method. To be used as a metal adsorbent, the adsorption of Cr (VI) from an aqueous solution by Cel-PEI was measured using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) techniques. The parameters of Cr (VI) adsorption in solution by the Cel-PEI adsorbent were as follows: the pH of the solution was 3, the concentration of the chromium solution was 100 mg/L, and the adsorption time was 180 min at 30 °C using 0.01 g of adsorbent. Cel-PEI had a Cr (VI) adsorption capacity of 106.60 mg/g, while the unadjusted Cel was 23.40 mg/g and the material recovery showed a decrease in efficiency of 22.19% and 54.27% in the second and third cycles, respectively. The absorption isotherm of chromium adsorption was also observed. The Cel-PEI material conformed to the Langmuir model with an R2 value of 0.9997. The kinetics of chromium adsorption showed that under pseudo-second-order analysis, with R2 values of 0.9909 and 0.9958 for Cel and Cel-PEI materials, respectively. The G° and H° values of the adsorption process were negative, indicating that the adsorption is spontaneous and that the adsorption process is exothermic. The efficient preparation adsorbent materials for Cr (VI) was achieved using a short microwave method that is low-cost and environmentally friendly for use in the treatment of Cr-contaminated wastewater.

Heavy metal ions and dyes in wastewater pose a severe hazard to ecological system and human health. This study used sulfamic acid (SA) to modify cellulose for adsorbent material preparation. The results from the structural characterization indicated that cellulose was successfully modified by introducing sulfonic acid groups to obtain sulfamic acid modified cellulose (SAMC). Subsequently, SAMC was prepared into spheres via being dissolved in ionic liquid and obtaining in antisolvent. The adsorption performance of SAMC aerogel spheres was investigated using methylene blue (MB) and lead ions (Pb2+). The maximum absorption capacity of SAMC aerogel spheres to MB and Pb2+ achieved 14.53 mg/g and 112.15 mg/g, respectively. The adsorption process conformed to the pseudo-second-order (PSO) model and Langmuir model. The adsorption mainly involved chemical action via coordination interaction between -SO32− and MB/Pb2+. Thermodynamic experiments confirmed that the adsorption process in the experiment was a spontaneous endothermic process. Therefore, this study provided a simple adsorbent production method for wastewater treatment.

Cellulose modification often employs chemical processes to tailor its properties and functionalities to fit the demands of a wide range of applications, maximizing its potential as a versatile and sustainable material. From both synthetic and environmental standpoints, one of the ultimate goals is to achieve significant modifications to enhance the end properties of the cellulose while minimizing the number of modified building blocks. The current study demonstrates that a synthetic glucose derivative, 6‐deoxy‐6‐fluoro‐glucose (6F‐Glc), fed into the fertilized cotton ovules, resulted in the accumulation of fluorine inside the cotton fibers with no apparent alteration to their morphology or development. These fibers exhibited a degree of substitution of 0.006, which is 170 times lower than that reported for chemical methods for cellulose modification. However, the physical characterization of the modified fibers showed a surprisingly large impact of this low‐level modification on the cellulose structure (e.g., hydrogen bonding network rearrangement) and a modest increase in the mechanical properties of the fibers. The obtained results exemplify the use of biological systems to introduce low quantities of new functionalities while maximizing the impact on fiber properties. Feeding cotton ovule cultures with a glucose derivative (6F‐Glc) leads to fibers with an exceptionally low degree of substitution. Despite this minimal modification, the fibers exhibit a modified structure and mechanical properties, highlighting the potential of harnessing biological systems for creating functionally modified cellulose fibers.