Nested seaweed cellulose fiber deposited with cuprous oxide nanorods for antimicrobial activity

Advances in the preparation and application of cellulose-based antimicrobial materials: A review

The rise of polymer materials in modern life has drawn attention to renewable, easily biodegradable, environmentally-friendly bio-based polymers. Notably, significant research has been dedicated to creating green antimicrobial functional materials for the biomedical field using natural polymer materials. Cellulose is a rich natural biomass organic polymer material. Given its favorable attributes like film-forming capability, biodegradability, and biocompatibility, it is extensively employed to tackle a wide range of challenges confronting humanity today. However, its inherent drawbacks, such as insolubility in water and most organic solvents, hygroscopic nature, difficulty in melting, and limited antimicrobial properties, continue to pose challenges for realizing the high-value applications of cellulose. Achieving multifunctionality and more efficient application of cellulose still poses major challenges. In this regard, the current development status of cellulose materials was reviewed, covering the classification, preparation methods, and application status of cellulose-based antimicrobial materials. The application value of cellulose-based antimicrobial materials in biomedicine, textiles, food packaging, cosmetics and wastewater treatment was summarised. Finally, insights were provided into the developing prospects of cellulose-based antimicrobial materials were provided.

Cellulose supported TiO2/Cu2O for highly asymmetric conjugate addition of α,β-unsaturated compounds in aqueous phase

A series of new kind green cellulose-supported bimetallic TiO2/Cu2O (Cell@TiO2/Cu2O) catalytic materials were obtained by in-situ reduction method employing cellulose as the carrier. The effects of metal percentage composition on the morphology and construction of the catalytic materials were systematically investigated. The Cell@TiO2/Cu2O were characterized by FT-IR, TG, XPS, SEM, TEM, EDS, and the element content was obtained by elemental analysis. Then, the achieved catalytic materials were applied to the chiral borylation reaction of α,β-unsaturated compounds, including nitrile compounds, esters, and α,β-unsaturated ketones. Remarkably, this approach provides an efficient strategy to gain an important class of chiral organic boron compounds with target chiral products in high yields as well as enantioselectivities. Besides, the Cell@TiO2/Cu2O could be easily recycled and effectively reused. This work constructed bimetallic TiO2/Cu2O on cellulose as a newly catalyst to obtain chiral boron compounds in aqueous phase.

Nanocellulose-based nanogenerators for sensor applications: A review

With the rapid development of the Internet of Things, nanogenerator as a green energy collection technology has attracted great attention in various fields. Specifically, the natural renewable nanocellulose as a raw material can significantly improve the environmental friendliness of the nanocellulose-based nanogenerators, which also makes the nanocellulose based nanogenerators expected to further develop in areas such as wearable devices and sensor networks. This paper mainly reports the application of nanocellulose in nanogenerator, focusing on the sensor. The types, sources and preparation methods of nanocellulose are briefly introduced. At the same time, the special structure of nanocellulose highlights the advantages of nanocellulose in nanogenerators. Then, the application of nanocellulose-based nanogenerators in sensors is introduced. Finally, the future development prospects and shortcomings of this nanogenerator are discussed.

Scope and challenges of seaweed utilization in food and nutraceutical industry in India: a review

Seaweeds are an excellent source of unique antioxidant phytochemicals, dietary fibres, essential amino acids, vitamins, polyunsaturated fatty acids and minerals. The presence of such structurally diverse and high value bioactive compounds has led to popularization of seaweed as functional food ingredient in global health supplement market. India, with a long coastline of 8100 km and exclusive economic zone of 2.17 million km2, is rich in diverse seaweed resources belonging to almost 700 species. However, food and nutraceutical application of Indian seaweed is highly constrained. Apart from Kappaphycus alvarezii, there is no systematic commercial cultivation of seaweed in India. The regulatory framework for use of seaweed as food is still developing and consumer acceptance is still low. However, there is a timely and renewed interest from different government agencies and research organisations to develop a thriving food and nutraceutical industry using India's vast seaweed resources. The review briefly describes the nutritional and functional food potential of the seaweed and goes on to discuss the scope of seaweed utilization in food and nutraceutical industry in India. Further, the review has identified the regulatory challenges and quality control requirements for use of seaweeds in food and nutraceuticals.

Low-cost biosorption of Fe(II) and Fe(III) from single and binary solutions using Ulva lactuca-derived cellulose nanocrystals-graphene oxide composite film

The marine algal biomass of Ulva lactuca was utilized for the extraction of cellulose and the development of cellulose nanocrystals/graphene oxide film. Cellulose nanocrystals with 50-150 nm were produced by H₂SO₄ hydrolysis of the algal cellulose. The adsorption efficiency of the nanocomposite film for Fe(II) and Fe(III) ions was successfully evaluated using Box-Behnken design. The maximum removal for Fe(II) (64.15%) could be attained at pH 5.13, adsorbent dosage 7.93 g L^-1 and Fe(II) concentration 15.39 mg L^-1, while the biosorption of Fe(III) was 69.92% at pH 5.0, adsorbent dosage 2 g L^-1, and Fe(III) concentration 15.0 mg L^-1. However, in the binary system, the removal efficiency of Fe(II) was enhanced to 95.48% at Fe(II):Fe(III) ratio of 1:1, while the Fe(III) removal was increased to 79.17% at ratio 1:2. The pseudo-second-order kinetics exhibited better fitting to the experimental results of Fe(II) and Fe(III) adsorption in both single and binary systems. The intra-particle diffusion was prominent during the biosorption, but the effect of the external mass transfer was significant. The Langmuir, Freundlich, Langmuir-Freundlich, Temkin, and Dubinin-Radushkevich isotherms showed satisfactory fitting to the experimental data, but they differ in priority based on iron state and pH. The adsorption of Fe(II) in the presence of Fe(III) in a mixture was best represented by the extended Langmuir model, while the extended Langmuir-Freundlich model best fitted the adsorption of Fe(III). The FT-IR analysis indicated that physisorption through electrostatic interaction/complexation is the predominant mechanism for the adsorption of iron using the nanocomposite film.

Nanocellulose: An amazing nanomaterial with diverse applications in food science

Recently, nanocellulose has gained growing interests in food science due to its many advantages including its broad resource of raw materials, renewability, interface stability, high surface area, mechanical strength, prebiotic characteristics, surface chemistry versatility and easy modification. Since then, this review summarized the sources, morphology, and structure characteristics of nanocellulose. Meanwhile, the mechanical, chemical, and combined treatment methods for the preparation of nanocellulose with desired properties were elaborated. Furthermore, the application of nanocellulose in Pickering emulsions, reinforced food packaging, functional food ingredient, food-grade hydrogels, and biosensors were emphasized. Finally, the safety, challenges, and future perspectives of nanocellulose were discussed. This work provided key developments and effective benefits of nanocellulose for future research opportunities in food.

A Comparison of Cooking Conditions of Rhizoclonium Pulp as a Substitute for Wood Pulp

The green macroalga Rhizoclonium was cooked with 5%, 10%, and 20% sodium hydroxide (NaOH) for 4 h (5-N, 10-N, and 20-N groups, respectively); with 5%, 10%, and 20% sodium sulfite (Na2SO3) for 4 h (5-NS, 10-NS, and 20-NS groups, respectively); and with 5%, 10%, and 20% NaOH for 2 h and 1% hydrogen peroxide (H2O2) for 2 h (5-NH, 10-NH, and 20-NH groups, respectively). The 5-NH handsheet showed the best mechanical properties; however, the 10-NH pulp was easier to separate than 5-NH during handsheet making, and 10-NH was more suitable for the industrial process. Thus, the 10-NH group showed the optimal production conditions with an optimal length/width ratio, crystallinity index (CI%), three-dimensional (3D) configuration, and mechanical strength. Substituting 20% 10-NH Rhizoclonium pulp with wood pulp had no significant effect on the mechanical properties of the 100% wood pulp handsheet. However, the fibers of the NS group were flatter and lost their 3D configuration, resulting in low mechanical strength. Overall, Rhizoclonium had its own optimal cooking condition, which was not the same as for wood pulp, and it has potential as a substitute for wood pulp in papermaking.

Lignocellulose in future biorefineries: Strategies for cost-effective production of biomaterials and bioenergy

Lignocellulosic biomass has been emerging as a biorefinery precursor for variety of biofuels, platform chemicals and biomaterials because of its specific surface morphology, exceptional physical, chemical and biological characteristics. The selection of proper raw materials, integration of nano biotechnological aspects, and designing of viable processes are important to attain a cost-effective route for the development of valuable end products. Lignocellulose-based materials can prove to be outstanding in terms of techno-economic viability, as well as being environmentally friendly and reducing effluent load. This review should facilitate the identification of better lignocellulosic sources, advanced pretreatments, and production of value-added products in order to boost the future industries in a cleaner and safer way.

In situ deposition of nano Cu2O on electrospun chitosan nanofibrous scaffolds and their antimicrobial properties

In order to obtain a synergistic antimicrobial effect of cuprous oxide nanoparticles (Cu₂O NPs) and chitosan (CS) nanofibers, the nano Cu₂O/CS nanofibrous scaffolds were synthesized in situ via two subsequent steps of chelation and reduction. The Cu²⁺ were stably chelated on CS nanofibrous scaffolds through the coordination of amino group (-NH₂) and hydroxyl group (-OH) on CS with Cu²⁺, and then the chelated Cu²⁺ were reduced to nano Cu₂O by Vitamin C under alkaline conditions. And by the measurements of XRD, XPS and FTIR-ATR, the results showed that Cu₂O NPs were successfully deposited on the CS nanofibrous scaffolds. SEM clarified that the particle size of Cu₂O gradually decreased and the shape changed from cubic to irregular with the increase of CuSO₄ concentration. With the CuSO₄ concentration of 0.02 and 0.04 mol·L^-1, the Cu₂O/CS nanofibrous scaffolds presented outstanding hydrophilicity and antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) comparing to the CS nanofibrous scaffolds, meanwhile, they possessed good biocompatibility. This kind of nanofibrous scaffolds deposited with nano Cu₂O would have broad application prospects in the field of antibacterial biomaterials.

Seaweed-based cellulose: Applications, and future perspectives

Cellulose is a naturally occurring organic polymer extracted mainly from lignocellulosic biomass of terrestrial origin. However, the increasing production of seaweeds for growing global market demands has developed the opportunity to use it as an additional cellulose source. This review aims to prepare comprehensive information to understand seaweed cellulose and its possible applications better. This is the first review that summarizes and discusses the cellulose from all three types (green, red, and brown) of seaweeds in various aspects such as contents, extraction strategies, and cellulose-based products. The seaweed cellulose applications and future perspectives are also discussed. Several seaweed species were found to have significant cellulose content (9-34% dry weight). The review highlights that the properties of seaweed cellulose-based products were comparable to products prepared from plant-based cellulose. Overall, this work demonstrates that cellulose could be economically extracted from phycocolloids industrial waste and selected cellulose-rich seaweed species for various commercial applications.

Nanocelluloses: Sources, Pretreatment, Isolations, Modification, and Its Application as the Drug Carriers

The 'Back-to-nature' concept has currently been adopted intensively in various industries, especially the pharmaceutical industry. In the past few decades, the overuse of synthetic chemicals has caused severe damage to the environment and ecosystem. One class of natural materials developed to substitute artificial chemicals in the pharmaceutical industries is the natural polymers, including cellulose and its derivatives. The development of nanocelluloses as nanocarriers in drug delivery systems has reached an advanced stage. Cellulose nanofiber (CNF), nanocrystal cellulose (NCC), and bacterial nanocellulose (BC) are the most common nanocellulose used as nanocarriers in drug delivery systems. Modification and functionalization using various processes and chemicals have been carried out to increase the adsorption and drug delivery performance of nanocellulose. Nanocellulose may be attached to the drug by physical interaction or chemical functionalization for covalent drug binding. Current development of nanocarrier formulations such as surfactant nanocellulose, ultra-lightweight porous materials, hydrogel, polyelectrolytes, and inorganic hybridizations has advanced to enable the construction of stimuli-responsive and specific recognition characteristics. Thus, an opportunity has emerged to develop a new generation of nanocellulose-based carriers that can modulate the drug conveyance for diverse drug characteristics. This review provides insights into selecting appropriate nanocellulose-based hybrid materials and the available modification routes to achieve satisfactory carrier performance and briefly discusses the essential criteria to achieve high-quality nanocellulose.

A review on the origin of nanofibers/nanorods structures and applications

In this review work, we highlight the origin of morphological structures such as nanofibers/nanorods in case of various materials in nano as well as bulk form. In addition, a discussion on different cations of different ionic radii and other intrinsic factors is provided. The materials (ceramic titanates, ferrites, hexaferrites, oxides, organic/inorganic composites, etc.,) exhibiting the nanofibers/nanorods like morphological structures are tabulated. Furthermore, the significance of nanofibers/nanorods obtained from distinct materials is elucidated in multiple scientific and technological fields. At the end, the device applications of these morphological species are also described in the current technology. The nucleation and growth mechanism of α-MnO₂ nanorods using natural extracts from Malus domestica and Vitis vinifera [3].

The "Maskne" microbiome - pathophysiology and therapeutics

"Maskne" is a new term coined during the 2020 COVID-19 pandemic. It refers to a subset of acne mechanica, deserving consideration in view of widespread reusable fabric mask-wearing to control the pandemic worldwide. Understanding of underlying pathophysiology directly relates to the novel skin microenvironment and textile-skin friction created by mask-wearing, distinct from nontextile-related acne mechanica previously linked to wearing of headgear. Specifically, the occlusive microenvironment leads to microbiome dysbiosis, which is linked to various dermatological conditions. Additional textile-skin interactions include factors such as breathability, stickiness sensations, moisture saturation, and hygiene maintenance. Increased skin temperatures can trigger sweat/heat-related dermatoses, and ear loops potentially trigger pressure-induced dermatoses. Important therapeutic considerations include increased skin irritation potential of conventional acne treatments under occlusion, exacerbation of chronic dermatoses, that is, perioral dermatitis, rosacea, and eczema, and susceptibility of these same patient groups to heightened discomfort with mask-wearing. Cotton, as the traditional fabric of choice for dermatology patients, has limited benefits in the context of face masks - increased subjective discomfort relates to increased moisture saturation and stickiness, inevitable because of high biofluid load of the nasal and oral orifices. Prolonged textile-skin contact time, directly proportional to the risk of maskne, can be an opportunity for the application of biofunctional textiles.

Nanocellulose from various biomass wastes: Its preparation and potential usages towards the high value-added products

Biomass waste comes from a wide range of sources, such as forest, agricultural, algae wastes, as well as other relevant industrial by-products. It is an important alternative energy source as well as a unique source for various bioproducts applied in many fields. For the past two decades, how to reuse, recycle and best recover various biomass wastes for high value-added bioproducts has received significant attention, which has not only come from various academia communities but also from many civil and medical industries. To summarize one of the cutting-edge technologies applied with nanocellulose biomaterials, this review focused on various preparation methods and strategies to make nanocellulose from diverse biomass wastes and their potential applications in biomedical areas and other promising new fields.

Electrodeposited Cu2O Nanopetal Architecture as a Superhydrophobic and Antibacterial Surface

Bacterial infections being sporadic and uncontrollable demands an urgent paradigm shift in the development of novel antibacterial agents. This work involves the fabrication of Cu₂O nanopetals over copper foil that show superlative antibacterial and superhydrophobic properties. A superhydrophobic surface has been fabricated using the electrochemical deposition (ECD) method. Here, it is aimed to establish the superior antibacterial activity as an outcome of the inherent superhydrophobic property of the as-fabricated nanostructures. The present study finds that the elevated value of the water contact angle (154 ± 0.6°) does not allow proper bacterial adhesion, and it is immune from the possibility of biofouling. Specifically, two kinds of bacterial strains have been tested and the time response of the antibacterial activity has been studied over a period of 12 h, taking DH5α Escherichia coli as a Gram-negative model and Bacillus subtilis 168 as a Gram-positive model. Higher antibacterial effects were observed for the Gram-negative model (E. coli) owing to its simplistic cell wall structure which facilitates the easy diffusion of Cu⁺ ions into the bacterial membrane. The simplicity of the developed method of fabrication along with the superlative superhydrophobic nature and excellent antibacterial property of the material, owing to its synergistic biophysical and biochemical modes of biocidal action, establishes its viability in many applications.