Optical, bactericidal and water repellent properties of electrospun nano-composite membranes of cellulose acetate and ZnO

Cutting-edge developments in zinc oxide nanoparticles: synthesis and applications for enhanced antimicrobial and UV protection in healthcare solutions

This paper presents a comprehensive review of recent advancements in utilizing zinc oxide nanoparticles (ZnO NPs) to enhance antimicrobial and UV protective properties in healthcare solutions. It delves into the synthesis techniques of ZnO NPs and elucidates their antimicrobial efficacy, exploring the underlying mechanisms governing their action against a spectrum of pathogens. Factors impacting the antimicrobial performance of ZnO NPs, including size, surface characteristics, and environmental variables, are extensively analyzed. Moreover, recent studies showcasing the effectiveness of ZnO NPs against diverse pathogens are critically examined, underscoring their potential utility in combatting microbial infections. The study further investigates the UV protective capabilities of ZnO NPs, elucidating the mechanisms by which they offer UV protection and reviewing recent innovations in leveraging them for UV-blocking applications in healthcare. It also dissects the factors influencing the UV shielding performance of ZnO NPs, such as particle size, dispersion quality, and surface coatings. Additionally, the paper addresses challenges associated with integrating ZnO NPs into healthcare products and presents future perspectives for overcoming these hurdles. It emphasizes the imperative for continued research efforts and collaborative initiatives to fully harness the potential of ZnO NPs in developing advanced healthcare solutions with augmented antimicrobial and UV protective attributes. By advancing our understanding and leveraging innovative approaches, ZnO NPs hold promise for addressing pressing healthcare needs and enhancing patient care outcomes.

Coconut husk-lignin derived carbon dots incorporated carrageenan based functional film for intelligent food packaging

Carbon dots (CDs) derived from sustainable natural feed-stocks like lignin have gained wide acceptance by virtue of their renewability and promising potential in intelligent sensing applications. The precursor lignin is isolated from agro-biomass waste, coconut husk through sodium hydroxide based extraction process. CDs are synthesised from amine functionalized lignin through solvothermal process and integrated into carrageenan biopolymer matrix (1, 2 and 3 wt%). The composite film with 2 wt% CDs (CARR2CD) showed optimum fluorescent emission intensity, excellent pH dependent fluorescent color change in the food pH range, reasonable tensile strength (46.50 ± 1.32 MPa) and 27 % increase in elongation at break. CDs imparted UV-light blocking properties (70 % UV-light) and enhanced hydrophobicity of the carrageenan matrix. CARR2CD film showed 84 % visible light transparency, 79 % reduction in oxygen transmittance rate (OTR), 81 % reduction in CO2 gas permeability and excellent antioxidant and antibacterial properties (against E. coli and S. aureus). As a practical application, the developed responsive packaging material is used to track pH change associated with milk spoilage via noticeable color change in fluorescent emission of the composite film. Thus, the developed responsive composite film paves a way for use as green and sustainable transparent intelligent food packaging material.

New insights into nanotherapeutics for periodontitis: a triple concerto of antimicrobial activity, immunomodulation and periodontium regeneration

Periodontitis is a chronic inflammatory disease caused by the local microbiome and the host immune response, resulting in periodontal structure damage and even tooth loss. Scaling and root planning combined with antibiotics are the conventional means of nonsurgical treatment of periodontitis, but they are insufficient to fully heal periodontitis due to intractable bacterial attachment and drug resistance. Novel and effective therapeutic options in clinical drug therapy remain scarce. Nanotherapeutics achieve stable cell targeting, oral retention and smart release by great flexibility in changing the chemical composition or physical characteristics of nanoparticles. Meanwhile, the protectiveness and high surface area to volume ratio of nanoparticles enable high drug loading, ensuring a remarkable therapeutic efficacy. Currently, the combination of advanced nanoparticles and novel therapeutic strategies is the most active research area in periodontitis treatment. In this review, we first introduce the pathogenesis of periodontitis, and then summarize the state-of-the-art nanotherapeutic strategies based on the triple concerto of antibacterial activity, immunomodulation and periodontium regeneration, particularly focusing on the therapeutic mechanism and ingenious design of nanomedicines. Finally, the challenges and prospects of nano therapy for periodontitis are discussed from the perspective of current treatment problems and future development trends.

Construction of cellulose acetate-based composite nanofiber films with effective antibacterial and filtration properties

In recent years, the safety of public health has attracted more and more attention. In order to avoid the spread of bacteria and reduce the diseases caused by their invasion of the human body, novel filtration and antibacterial materials have attracted more and more attention. In this work, the antibacterial agents silver nanoparticles (AgNPs) and cetylpyridine bromide (CPB) were introduced into a cellulose acetate (CA) nanofiber film by electrospinning technology to prepare CA-based composite films with good antibacterial and filtration properties. The results of the antibacterial test of the composite nanofiber films showed that AgNPs and CPB had synergistic antibacterial effects and exhibited good antibacterial properties against a variety of bacteria. In addition, in vitro cytotoxicity, skin irritation and skin sensitization experiments proved that the CA/AgNPs, CA/CPB and CA/CPB/AgNPs films produced no skin irritation or sensitization in the short term. These are expected to become potential materials for the preparation of new antibacterial masks. This work provides a new idea for developing materials with good antibacterial properties for enhancing protection via filtration masks.

Progress on Improved Fouling Resistance-Nanofibrous Membrane for Membrane Distillation: A Mini-Review

Nanofibrous membranes for membrane distillation (MD) have demonstrated promising results in treating various water and wastewater streams. Significant progress has been made in recent decades because of the development of sophisticated membrane materials, such as superhydrophobic, omniphobic and Janus membranes. However, fouling and wetting remain crucial issues for long-term operation. This mini-review summarizes ideas as well as their limitations in understanding the fouling in membrane distillation, comprising organic, inorganic and biofouling. This review also provides progress in developing antifouling nanofibrous membranes for membrane distillation and ongoing modifications on nanofiber membranes for improved membrane distillation performance. Lastly, challenges and future ways to develop antifouling nanofiber membranes for MD application have been systematically elaborated. The present mini-review will interest scientists and engineers searching for the progress in MD development and its solutions to the MD fouling issues.

Synergistic effect of GO/ZnO loading on the performance of cellulose acetate/chitosan blended reverse osmosis membranes for NOM rejection

Declining freshwater resources along with their pollution are threatening the life existence on earth. To meet the freshwater demand, one of the most appropriate and possible ways which has been adopted all over the world is to reuse wastewater by removing its impurities. Among many water pollutants, natural organic matter (NOM) is found to be responsible as major precursor for the formation of other pollutants. Removal of NOM from wastewater is being done by using membrane filtration systems incorporated with certain nanofillers to increase membranes efficiency and permeability. In this study, novel nanocomposite reverse osmosis (RO) membranes were prepared using cellulose acetate and chitosan in N,N-Dimethyl formamide. Graphene oxide (GO) nanosheets and zinc oxide (ZnO) in different concentration were loaded to modify the membranes for tuning their RO performance. The confirmation of the functional groups is demonstrated by Fourier transform infrared spectroscopy which revealed the specific peaks indicating the formation of the nano-composite membranes. The surface morphology was studied by scanning electronic microscopy which shows a gradual transformation of the membrane surface from voids-free to macro-voids filled surface up to threshold concentration of GO and ZnO. The thermal properties of GO based membranes were analyzed using thermogravimetric analysis and differential scanning calorimetry. The uniform interaction of the GO and ZnO with polymers induced the remarkable thermal properties of the synthesized membranes. Permeate flux and contact angle measurements were considered to estimate their water content (96%) capacity and NOM rejection (96%) using 0.1 ppm humic acid solution. The permeate flux, NOM rejection and the water content changed directly with GO and inversely with ZnO wt% in the membranes up to GO5 (GO:0.14: ZnO:0.03) whereas the contact angle exhibited the inverse relationship with GO and ZnO concentration in casting solution of the synthesized membranes. Hence it can be concluded that prepared RO membranes are suitable for NOM rejection and recommended for water treatment.

Impact of Ag/ZnO Reinforcements on the Anticancer and Biological Performances of CA@Ag/ZnO Nanocomposite Materials

In this study, an unpretentious, non-toxic, and cost-effective dissolution casting method was utilized to synthesize a group of anticancer and biologically active hybrid nanocomposite materials containing biopolymer cellulose acetate. Pristine ZnO and Ag_{(0.01, 0.05, 0.1)}/ZnO hybrid nanofillers based on variable Ag NP loadings were prepared via green procedures in the presence of gum arabic (GA). The chemical structures and the morphological features of the designed nanocomposite materials were investigated by PXRD, TEM, SEM, FTIR, TGA, and XPS characterization techniques. The characterization techniques confirmed the formation of CA@Ag_{(0.01, 0.05, 0.1)}/ZnO hybrid nanocomposite materials with an average crystallite size of 15 nm. All investigated materials showed two degradation steps. The thermal stability of the fabricated samples was ranked in the following order: CA/ZnO < CA@Ag_(0.01)/ZnO < CA@Ag_(0.05)/ZnO = CA@Ag_(0.1)/ZnO. Hence, the higher Ag doping level slightly enhanced the thermal stability. The developed nanocomposites were tested against six pathogens and were used as the target material to reduce the number of cancer cells. The presence of Ag NPs had a positive impact on the biological and the anticancer activities of the CA-reinforced Ag/ZnO composite materials. The CA@Ag_(0.1)/ZnO hybrid nanocomposite membrane had the highest antimicrobial activity in comparison to the other fabricated materials. Furthermore, the developed CA@Ag_(0.1)/ZnO hybrid nanocomposite material effectively induced cell death in breast cancer.

In Situ Synthesis of AZO-Np in Guar Gum/PVOH Composite Fiber Mats for Potential Bactericidal Release

Since the number of antibiotic-resistant bacterial infections is growing and cases are getting worse every year, the search for new alternative bactericidal wound dressing treatments is becoming crucial. Within this context, the use of polysaccharides from plants and seeds in innovative biopolymer technologies is of key importance. In this work, bio-nano-composite guar gum/polyvinyl alcohol (PVOH) membranes loaded with aluminum-doped zinc oxide nanoparticles were produced via electrospinning. Citric acid was added to the mixture to increase spinnability. However, depending on the pH, zinc oxide nanoparticles are partially dissociated, decreasing their bactericidal efficiency. Thus, a second successful alkaline thermo-chemical regrowth step was added to the process to treat the obtained fibers. This alkaline thermo-chemical treatment reconstituted both the nanoparticles and their bactericidal properties. The Staphylococcus aureus antibacterial assay results show that the membranes obtained after the alkaline thermo-chemical treatment presented a 57% increase in growth inhibition.

Photocatalytic Degradation of Textile Dye on Blended Cellulose Acetate Membranes

This work aimed to investigate the degradation performance of natural cellulose acetate (CA) membranes filled with ZnO nanostructures. Photocatalytic degradation of reactive toxic dye methylene blue (MB) was studied as a model reaction using UV light. A CA membrane was previously casted and fabricated through the phase inversion processes and laboratory-synthesized ZnO microparticles as filler. The prepared membrane was characterized for pore size, ultrafiltration (UF) performance, porosity, morphology using scanning electron micrographs (SEM), water contact angle and catalytic degradation of MB. The prepared membrane shows a significant amount of photocatalytic oxidation under UV. The photocatalytic results under UV-light radiation in CA filled with ZnO nanoparticles (CA/ZnO) demonstrated faster and more efficient MB degradation, resulting in more than 30% of initial concentration. The results also revealed how the CA/ZnO combination effectively improves the membrane’s photocatalytic activity toward methylene blue (MB), showing that the degradation process of dye solutions to UV light is chemically and physically stable and cost-effective. This photocatalytic activity toward MB of the cellulose acetate membranes has the potential to make these membranes serious competitors for removing textile dye and other pollutants from aqueous solutions. Hence, polymer–ZnO composite membranes were considered a valuable and attractive topic in membrane technology.

Fouling Prevention in Polymeric Membranes by Radiation Induced Graft Copolymerization

The application of membrane processes in various fields has now undergone accelerated developments, despite the presence of some hurdles impacting the process efficiency. Fouling is arguably the main hindrance for a wider implementation of polymeric membranes, particularly in pressure-driven membrane processes, causing higher costs of energy, operation, and maintenance. Radiation induced graft copolymerization (RIGC) is a powerful versatile technique for covalently imparting selected chemical functionalities to membranes' surfaces, providing a potential solution to fouling problems. This article aims to systematically review the progress in modifications of polymeric membranes by RIGC of polar monomers onto membranes using various low- and high-energy radiation sources (UV, plasma, γ-rays, and electron beam) for fouling prevention. The feasibility of the modification method with respect to physico-chemical and antifouling properties of the membrane is discussed. Furthermore, the major challenges to the modified membranes in terms of sustainability are outlined and the future research directions are also highlighted. It is expected that this review would attract the attention of membrane developers, users, researchers, and scientists to appreciate the merits of using RIGC for modifying polymeric membranes to mitigate the fouling issue, increase membrane lifespan, and enhance the membrane system efficiency.

Antibacterial, Antioxidation, UV-Blocking, and Biodegradable Soy Protein Isolate Food Packaging Film with Mangosteen Peel Extract and ZnO Nanoparticles

The objective of this study was to prepare a functional biodegradable soy protein isolate (SPI) food packaging film by introducing a natural antimicrobial agent, mangosteen peel extract (MPE, 10 wt% based on SPI), and different concentrations of functional modifiers, ZnO NPs, into the natural polymer SPI by solution casting method. The physical, antioxidant, antibacterial properties and chemical structures were also investigated. The composite film with 5% ZnO NPs had the maximum tensile strength of 8.84 MPa and the lowest water vapor transmission rate of 9.23 g mm/m² h Pa. The composite film also exhibited excellent UV-blocking, antioxidant, and antibacterial properties against Escherichia coli and Staphylococcus aureus. The TGA results showed that the introduction of MPE and ZnO NPs improved the thermal stability of SPI films. The microstructure of the films was analyzed by SEM to determine the smooth surface of the composite films. ATR-FTIR and XPS analyses demonstrated the strong hydrogen bonding of SPI, MPE, and ZnO NPs in the films. The presence of ZnO NPs in the composite films was also proved by EDX and XRD. These results suggest that SPI/MPE/ZnO composite film is promising for food-active packaging to extend the shelf life of food products.

Photocatalytic Degradation of Methylene Blue Using Polymeric Membranes Based on Cellulose Acetate Impregnated with ZnO Nanostructures

This paper studied the photocatalytic degradation of methylene blue (MB) using polymeric membrane impregnated with ZnO nanostructures under UV-light and sunlight irradiation. ZnO nanoparticles and ZnO nanowires were prepared using the hydrothermal technique. Cellulose acetate polymeric membranes were fabricated by the phase inversion method using dimethylformamide (DMF) as a solvent and ZnO nanostructures. The structural properties of the nanostructures and the membranes were investigated using XRD, SEM, FTIR, and TGA measurements. The membranes were tested for photocatalytic degradation of MB using a UV lamp and a sunlight simulator. The photocatalytic results under sunlight irradiation in the presence of cellulose acetate impregnated with ZnO nanoparticles (CA-ZnO-NP) showed a more rapid degradation of MB (about 75%) compared to the results obtained under UV-light irradiation degradation (about 30%). The results show that CA-ZnO-NP possesses the photocatalytic ability to degrade MB efficiently at different levels under UV-light and sunlight irradiation. Modified membranes with ZnO nanoparticles and ZnO nanowires were found to be chemically stable, recyclable, and reproducible. The addition of ZnO nanostructure to the cellulose membranes generally enhanced their photocatalytic activity toward MB, making these potential membranes candidates for removing organic pollutants from aqueous solutions.

Architecting functionalized carbon microtube/carrollite nanocomposite demonstrating significant microwave characteristics

Biomass-derived materials have recently received considerable attention as lightweight, low-cost, and green microwave absorbers. On the other hand, sulfide nanostructures due to their narrow band gaps have demonstrated significant microwave characteristics. In this research, carbon microtubes were fabricated using a biowaste and then functionalized by a novel complementary solvothermal and sonochemistry method. The functionalized carbon microtubes (FCMT) were ornamented by CuCo2S4 nanoparticles as a novel spinel sulfide microwave absorber. The prepared structures illustrated narrow energy band gap and deposition of the sulfide structures augmented the polarizability, desirable for dielectric loss and microwave attenuation. Eventually, the architected structures were blended by polyacrylonitrile (PAN) to estimate their microwave absorbing and antibacterial characteristics. The antibacterial properties against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were scrupulously assessed. Noteworthy, the maximum reflection loss (RL) of the CuCo2S4/PAN with a thickness of 1.75 mm was 61.88 dB at 11.60 GHz, while the architected FCMT/PAN composite gained a broadband efficient bandwidth as wide as 7.91 GHz (RL > 10 dB) and 3.25 GHz (RL > 20 dB) with a thickness of 2.00 mm. More significantly, FCMT/CuCo2S4/PAN demonstrated an efficient bandwidth of 2.04 GHz (RL > 20 dB) with only 1.75 mm in thickness. Interestingly, FCMT/CuCo2S4/PAN and CuCo2S4/PAN composites demonstrated an electromagnetic interference shielding efficiency of more than 90 and 97% at the entire x and ku-band frequencies, respectively.

Idiosyncratic cellulose acetate nanocomposite membranes: synthesis and performance control study for desalination

In order to enhance the characteristic performance of cellulose acetate (CA) membranes, a novel nanofiller synergy is adopted herein for desalination purpose. Activated zinc oxide and aero-silica synergy in seven different ratio based combinations were introduced into CA matrix adopting solution mixing technique. The functionalized nanofillers loading impact on membranes surface texture, crystalline structural difference, functional groups presence, thermal decomposition and phase transition temperatures were scrutinized. The sole membranes were practically employed to determine salts (NaCl and MgCl₂) rejection tested by dead-end filtration system. Time dependent flux rate and fouling study were performed to decide the reuseability of nanocomposite membranes. The results validate a remarkable improvement by idiosyncratically synthesized nanocomposite membranes.

High pressure laminates reinforced with electrospun cellulose acetate nanofibers

In the work, the non-woven cellulose acetate (CA) nanofiber mats were prepared via electrospinning, and CA nanofiber were incorporated into the core layer of the high-pressure laminates (HPLs). When the concentration of CA was 16 wt%, SEM images demonstrated that the morphology of the CA nanofiber mat was the best, with an average diameter of 654±246 nm. When CA nanofiber mats were incorporated into the core layer of HPLs, the mechanical properties of the resulted HPLs composites were significantly improved. Specifically, the tensile strength and elongation at break of the nanofiber mats reinforced HPLs composites increased remarkably to 40.8 ±1.1 MPa and 27.9 ± 0.9 %, respectively, which were nearly 6 times and 4.4 times higher than those of the pure HPLs. Furthermore, the incorporation of the CA nanofiber mats also significantly improved the flame retardancy of the HPLs, which was revealed from the thermogravimetric analysis (TGA) results.

Gelatin-Based Nanocomposite Film with Bacterial Cellulose–MgO Nanoparticles and Its Application in Packaging of Preserved Eggs

Preserved eggs are prone to lose water during storage, which causes the preserved eggs to shrink and have poor taste, bad flavor, and reduced quality. By studying a degradable coating agent and applying it to preserved eggs, we explored its effect on the quality of preserved eggs during storage. In this paper, the structure and performance of gelatin film (GF), gelatin–bacterial cellulose film (GBF), and gelatin–bacterial cellulose–MgO nanocomposite film (GBMF) were explored by adding bacterial cellulose (BC) and MgO nanoparticles to gelatin. The results showed that the BC solution increased the particle size and absolute value of the zeta potential. The cross-sectional microstructure of the film showed fewer and smaller pores. The water vapor permeability (WVP) decreased, and the elongation at break (EB) increased significantly. The addition of MgO nanoparticles increased the particle size and reduced the absolute value of the zeta potential. The cross section of the film became denser and more uniform by adding MgO nanoparticles, and the surface hydrophobicity of the film increased, and the EB decreased. After coating the preserved eggs with these films, the weight loss rate, the content of total volatile base nitrogen (TVB-N), and the hardness were lower than that of uncoated preserved eggs. The pH of the uncoated preserved eggs also dropped faster than the coated preserved eggs. Moreover, the preserved egg coated with GBMF had the lowest weight loss rate and the highest sensory score. It can be seen that these three films had a certain preservation effect on preserved eggs, and the GBMF had the best preservation effect.

Electrospun degradable Zn-Mn oxide hierarchical nanofibers for specific capture and efficient release of circulating tumor cells

Constructing biological affinity devices is considered as an effective strategy for isolating circulating tumor cells (CTCs), and electrospun nanofibers (ESNFs) have recently received attention. However, the current research focuses on polymer fibers, and fabricating stimuli-responsive inorganic nanofibers for cancer diagnosis and analysis is still challenging. In this work, Zn-Mn oxide nanofibers (ZnMnNFs) are used to capture and purify cancer cells after modification with specific antibodies. Then, the hierarchical nanofibers are degraded by reductive weak acid to release the captured cells efficiently without residues. Fusion of Zn and Mn, two transition metals, enhances the surface activity of oxides so that ZnMnNFs are easier to be degraded and modified. By using MCF-7 cancer cells, the cell capture efficiency of ZnMnNFs is up to 88.2%. Furthermore, by using citric acid, it is discovered that, by comparison with Mn oxide nanofibers, the cell release efficiency of ZnMnNFs is improved to 95.1% from 15.4%. In addition, the viability of released cells exceeds 90%. Lastly, the robustness of ZnMnNFs substrates is tested in peripheral blood from breast cancer patients (BCP) and colorectal cancer patients (CCP). Combined with fluorescence labeling, CTCs are confirmed to be isolated from all the clinical samples. This is the first trial of using ternary inorganic ESNFs for cancer cell capture. It is anticipated that the degradable ESNFs will provide biocompatible theranostic platforms and overcome the current limitations of cell release for high-precision gene analysis.

Biodegradable CA/CPB electrospun nanofibers for efficient retention of airborne nanoparticles

The increase of the industrialization process brought the growth of pollutant emissions into the atmosphere. At the same time, the demand for advances in aerosol filtration is evolving towards more sustainable technologies. Electrospinning is gaining notoriety, once it enables to produce polymeric nanofibers with different additives and also the obtaining of small pore sizes and fiber diameters; desirable features for air filtration materials. Therefore, this work aims to evaluate the filtration performance of cellulose acetate (CA) nanofibers and cationic surfactant cetylpyridinium bromide (CPB) produced by electrospinning technique for retention of aerosol nanoparticles. The pressure drop and collection efficiency measurements of sodium chloride (NaCl) aerosol particles (diameters from 7 to 300 nm) were performed using Scanning Mobility Particle Sizer (SMPS). The average diameter of the electrospun nanofibers used was 239 nm, ranging from 113 to 398 nm. Experimental results indicated that the nanofibers showed good permeability (10^-11 m²) and high-efficiency filtration for aerosol nanoparticles (about 100 %), which can include black carbon (BC) and the new coronavirus. The pressure drop was 1.8 kPa at 1.6 cm s^-1, which is similar to reported for some high-efficiency nanofiber filters. In addition, it also retains BC particles present in air, which was about 90 % for 375 nm and about 60 % for the 880 nm wavelength. Finally, this research provided information for future designs of indoor air filters and filter media for facial masks with renewable, non-toxic biodegradable, and potential antibacterial characteristics.

Bio-Based Electrospun Fibers for Wound Healing

Being designated to protect other tissues, skin is the first and largest human body organ to be injured and for this reason, it is accredited with a high capacity for self-repairing. However, in the case of profound lesions or large surface loss, the natural wound healing process may be ineffective or insufficient, leading to detrimental and painful conditions that require repair adjuvants and tissue substitutes. In addition to the conventional wound care options, biodegradable polymers, both synthetic and biologic origin, are gaining increased importance for their high biocompatibility, biodegradation, and bioactive properties, such as antimicrobial, immunomodulatory, cell proliferative, and angiogenic. To create a microenvironment suitable for the healing process, a key property is the ability of a polymer to be spun into submicrometric fibers (e.g., via electrospinning), since they mimic the fibrous extracellular matrix and can support neo- tissue growth. A number of biodegradable polymers used in the biomedical sector comply with the definition of bio-based polymers (known also as biopolymers), which are recently being used in other industrial sectors for reducing the material and energy impact on the environment, as they are derived from renewable biological resources. In this review, after a description of the fundamental concepts of wound healing, with emphasis on advanced wound dressings, the recent developments of bio-based natural and synthetic electrospun structures for efficient wound healing applications are highlighted and discussed. This review aims to improve awareness on the use of bio-based polymers in medical devices.

A Review on Plant Cellulose Nanofibre-Based Aerogels for Biomedical Applications

Cellulose nanomaterials from plant fibre provide various potential applications (i.e., biomedical, automotive, packaging, etc.). The biomedical application of nanocellulose isolated from plant fibre, which is a carbohydrate-based source, is very viable in the 21st century. The essential characteristics of plant fibre-based nanocellulose, which include its molecular, tensile and mechanical properties, as well as its biodegradability potential, have been widely explored for functional materials in the preparation of aerogel. Plant cellulose nano fibre (CNF)-based aerogels are novel functional materials that have attracted remarkable interest. In recent years, CNF aerogel has been extensively used in the biomedical field due to its biocompatibility, renewability and biodegradability. The effective surface area of CNFs influences broad applications in biological and medical studies such as sustainable antibiotic delivery for wound healing, the preparation of scaffolds for tissue cultures, the development of drug delivery systems, biosensing and an antimicrobial film for wound healing. Many researchers have a growing interest in using CNF-based aerogels in the mentioned applications. The application of cellulose-based materials is widely reported in the literature. However, only a few studies discuss the potential of cellulose nanofibre aerogel in detail. The potential applications of CNF aerogel include composites, organic-inorganic hybrids, gels, foams, aerogels/xerogels, coatings and nano-paper, bioactive and wound dressing materials and bioconversion. The potential applications of CNF have rarely been a subject of extensive review. Thus, extensive studies to develop materials with cheaper and better properties, high prospects and effectiveness for many applications are the focus of the present work. The present review focuses on the evolution of aerogels via characterisation studies on the isolation of CNF-based aerogels. The study concludes with a description of the potential and challenges of developing sustainable materials for biomedical applications.

Functionalized Electrospun Nanofibers as a Versatile Platform for Colorimetric Detection of Heavy Metal Ions in Water: A Review

The increasing heavy metal pollution in the aquatic ecosystem mainly driven by industrial activities has raised severe concerns over human and environmental health that apparently necessitate the design and development of ideal strategies for the effective monitoring of heavy metals. In this regard, colorimetric detection provides excellent opportunities for the easy monitoring of heavy metal ions, and especially, corresponding solid-state sensors enable potential opportunities for their applicability in real-world monitoring. As a result of the significant interest originating from their simplicity, exceptional characteristics, and applicability, the electrospun nanofiber-based colorimetric detection of heavy metal ions has undergone radical developments in the recent decade. This review illustrates the range of various approaches and functional molecules employed in the fabrication of electrospun nanofibers intended for the colorimetric detection of various metal ions in water. We highlight relevant investigations on the fabrication of functionalized electrospun nanofibers encompassing different approaches and functional molecules along with their sensing performance. Furthermore, we discuss upcoming prospectus and future opportunities in the exploration of designing electrospun nanofiber-based colorimetric sensors for real-world applications.

Omniphobic re-entrant PVDF membrane with ZnO nanoparticles composite for desalination of low surface tension oily seawater

In this study, an omniphobic membrane was fabricated by electrospraying fluorinated zinc oxide (ZnO) nanoparticles (NPs) mixed with polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) on the surface of an organosilane functionalized polyvinylidene difluoride (PVDF) membrane. Our results revealed that the functionalized ZnO NPs membrane exhibited a rough hierarchical re-entrant morphology with low surface energy which allowed it to achieve high omniphobic characteristics. It was observed that the addition of 30% ZnO (w/w of PVDF-HFP) was found to be optimal and imparted a high repulsive characteristic. The optimized PVDF/ZnO(30)/FAS/PVDF-HFP referred as cPFP-30Z membrane exhibited a high contact angle values of 159.0 ± 3.1°, 129.6 ± 2.2°, 130.4 ± 4.1° and 126.1 ± 1.2° for water, sodium dodecyl sulfate (SDS) saline solution (0.3 mM SDS in 3.5% NaCl), ethanol, and vegetable oil, respectively. The low surface energy and high surface roughness (Ra) of optimised membrane was assessed as 0.78 ± 0.14 mN m^-1 and 1.37 μm, respectively. Additionally, in contrast with the commercial PVDF membrane, the cPFP-30Z membrane exhibited superior anti-wetting/anti-fouling characteristics and high salt rejection performance (>99%) when operated with a saline oil solution (0.015 v/v) and SDS (0.4 mM) feed solutions.

ZnO Nanostructures and Electrospun ZnO-Polymeric Hybrid Nanomaterials in Biomedical, Health, and Sustainability Applications

ZnO-based nanomaterials are a subject of increasing interest within current research, because of their multifunctional properties, such as piezoelectricity, semi-conductivity, ultraviolet absorption, optical transparency, and photoluminescence, as well as their low toxicity, biodegradability, low cost, and versatility in achieving diverse shapes. Among the numerous fields of application, the use of nanostructured ZnO is increasingly widespread also in the biomedical and healthcare sectors, thanks to its antiseptic and antibacterial properties, role as a promoter in tissue regeneration, selectivity for specific cell lines, and drug delivery function, as well as its electrochemical and optical properties, which make it a good candidate for biomedical applications. Because of its growing use, understanding the toxicity of ZnO nanomaterials and their interaction with biological systems is crucial for manufacturing relevant engineering materials. In the last few years, ZnO nanostructures were also used to functionalize polymer matrices to produce hybrid composite materials with new properties. Among the numerous manufacturing methods, electrospinning is becoming a mainstream technique for the production of scaffolds and mats made of polymeric and metal-oxide nanofibers. In this review, we focus on toxicological aspects and recent developments in the use of ZnO-based nanomaterials for biomedical, healthcare, and sustainability applications, either alone or loaded inside polymeric matrices to make electrospun composite nanomaterials. Bibliographic data were compared and analyzed with the aim of giving homogeneity to the results and highlighting reference trends useful for obtaining a fresh perspective about the toxicity of ZnO nanostructures and their underlying mechanisms for the materials and engineering community.

Multifunctional nanocellulose/metal and metal oxide nanoparticle hybrid nanomaterials

Nanocellulose materials are derived from cellulose, the most abundant biopolymer on the earth. Nanocellulose have been extensively used in the field of food packaging materials, wastewater treatment, drug delivery, tissue engineering, hydrogels, aerogels, sensors, pharmaceuticals, and electronic sectors due to their unique chemical structure and excellent mechanical properties. On the other hand, metal and metal oxide nanoparticles (NP) such as Ag NP, ZnO NP, CuO NP, and Fe₃O₄ NP have a variety of functional properties such as UV-barrier, antimicrobial, and magnetic properties. Recently, nanocelluloses materials have been used as a green template for producing metal or metal oxide nanoparticles. As a result, multifunctional nanocellulose/metal or metal oxide hybrid nanomaterials with high antibacterial properties, ultraviolet barrier properties, and mechanical properties were prepared. This review emphasized recent information on the synthesis, properties, and potential applications of multifunctional nanocellulose-based hybrid nanomaterials with metal or metal oxides such as Ag NP, ZnO NP, CuO NP, and Fe₃O₄ NP. The nanocellulose-based hybrid nanomaterials have huge potential applications in the area of food packaging, biopharmaceuticals, biomedical, and cosmetics.

Ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications

Cellulose acetate (CA), viscose, or artificial silk are biocompatible human-benign derivatives of cellulose, one of the most abundant biopolymers on earth. While various optical materials have been developed from CA, optical CA nanomaterials are nonexistent. Here we report on the assembly of a new family of extremely bright fluorescent CA nanoparticles (CA-dots), which are fully suitable for in vivo imaging / targeting applications. CA-dots can encapsulate a variety of molecular fluorophores. Using various commercially available fluorophores, we demonstrate that the fluorescence of CA-dots can be tuned within the entire UV-VIS-NIR spectrum. We also demonstrate excellent specific targeting of tumors in vivo, when injected in blood in zebrafish (xenograft model of human cervical epithelial cancer), and unusually strong ex-vivo topical labeling of colon cancer in mice utilizing CA folate-functionalized nanoparticles.

A cyclodextrin polymer membrane-based passive sampler for measuring triclocarban, triclosan and methyl triclosan in rivers

In recent years, extensive attention has been paid to the passive sampling technology of diffusive gradients in thin films (DGT) due to its growing application in the measurement of a widening variety of compounds. Within any DGT device, the binding phase is a key component, and seeking novel binding phases is an issue worth studying. Cyclodextrin polymer, as a green and eco-friendly material, may be a good choice for measuring organic chemicals. In this study, a novel DGT sampler with cyclodextrin polymer membrane (CDPM) as the binding phase was developed for measuring the concentrations of triclosan, triclocarban and methyl triclosan. Firstly, the type and content of cyclodextrin used in CDPM was optimized, and a series of tests showed that CDPM had good hydrophilicity, thermal stability, fast uptake rate and sufficient uptake capacity, thus CDPM was determined to be suitable for use as the binding phase of DGT sampler. Moreover, the sampling rates of this DGT sampler were not influenced by ionic strength and dissolved organic matter, making it feasible for in situ monitoring of compounds in the field. Hence, we deployed the developed DGT sampler in the Qinhuai and Jiuxiang Rivers to measure the concentrations of three compounds. We also collected water samples and processed them with the solid phase extraction (SPE) method. Results indicated that there was no significant difference between the DGT-measured and the SPE-measured concentrations for each compound, which confirmed the reliability of this DGT sampler for monitoring the concentrations of compounds in natural waters.

Synergistic effect of PANI-ZrO2 composite as antibacterial, anti-corrosion, and phosphate adsorbent material: synthesis, characterization and applications

The increasing number of bacteria-related problems and presence of trace amounts of phosphate in treated wastewater effluents have become a growing concern in environmental research. The use of antibacterial agents and phosphate adsorbents for the treatment of wastewater effluents is of great importance. In this study, the potential applications of a synthesized polyaniline (PANI)-zirconium dioxide (ZrO₂) composite as an antibacterial, phosphate adsorbent and anti-corrosion material were systematically investigated. The results of an antibacterial test reveal an effective area of inhibition of 14 and 18 mm for the Escherichia coli and Staphylococcus aureus bacterial strains, respectively. The antibacterial efficiency of the PANI-ZrO₂ composite is twice that of commercial ZrO₂. In particular, the introduction of PANI increased the specific surface area and roughness of the composite material, which was beneficial to increase the contact area with bacterial and phosphate. The experimental results demonstrated that phosphate adsorption studies using 200 mg P/L phosphate solution showed a significant phosphate removal efficiency of 64.4%, and the maximum adsorption capacity of phosphate on the solid surface of PANI-ZrO₂ is 32.4 mg P/g. Furthermore, PANI-ZrO₂ coated on iron substrate was tested for anti-corrosion studies by a natural salt spray test (7.5% NaCl), which resulted in the formation of no rust. To the best of our knowledge, no works have been reported on the synergistic effects of the PANI-ZrO₂ composite as an antibacterial, anti-corrosion, and phosphate adsorbent material. PANI-ZrO₂ composite is expected to be a promising comprehensive treatment method for water filters in the aquaculture industry and for use in water purification applications.

Starch-Based Flexible Coating for Food Packaging Paper with Exceptional Hydrophobicity and Antimicrobial Activity

Herein, we fabricated a starch-based flexible coating for food packaging papers with excellent hydrophobicity and antimicrobial properties. FTIR (Fourier transform infrared) and XRD (X-ray diffraction) spectra revealed the homogeneous dispersion of the ZnO nanoparticles (NPs) in the composite film within 5% ZnO NP dosage. SEM (scanning electron microscope) and AFM (atomic force microscope) micrographs confirmed the increased roughness on the composite film with the increased dosages of ZnO NPs. Hydrophobic characteristics showed that dramatic enhancement was obtained in the values and stabilities of DCAs (dynamic contact angles) in the resultant film and coated paper. TG (thermogravimetry) results demonstrated the increased thermal stabilities of the composite films. Significantly, a decreased water vapor transmission rate was observed in the coated paper. When 20% guanidine-based starch and 2% CMC (carboxy methyl cellulose) was added, a flexible coating with excellent antimicrobial activity towards Escherichia coli can be obtained. Furthermore, the migration of ZnO NPs into the food simulants was well below the overall migration legislative limit. The resultant starch-based flexible composite film and coated paper established an effective approach to develop a green-based material for food packaging applications.

Nanocellulose-Based Antibacterial Materials

In recent years, nanocellulose-based antimicrobial materials have attracted a great deal of attention due to their unique and potentially useful features. In this review, several representative types of nanocellulose and modification methods for antimicrobial applications are mainly focused on. Recent literature related with the preparation and applications of nanocellulose-based antimicrobial materials is reviewed. The fabrication of nanocellulose-based antimicrobial materials for wound dressings, drug carriers, and packaging materials is the focus of the research. The most important additives employed in the preparation of nanocellulose-based antimicrobial materials are presented, such as antibiotics, metal, and metal oxide nanoparticles, as well as chitosan. These nanocellulose-based antimicrobial materials can benefit many applications including wound dressings, drug carriers, and packaging materials. Finally, the challenges of industrial production and potentials for development of nanocellulose-based antimicrobial materials are discussed.

Sustained antibacterial activity of berberine hydrochloride loaded supramolecular organoclay networks with hydrogen-bonding junctions

The environmental risk from antibiotics is an issue of increasing concern. So, carboxymethyl β-cyclodextrin-functionalized montmorillonite nanosheets were for the first time successfully synthesized through a cheap, environmentally friendly and scalable approach and confirmed by FTIR, XRD and TGA. FE-SEM investigation showed that the resulting functional material could be further self-assembled into dense supramolecular organoclay networks (D-networks). The antibacterial properties of the D-networks loaded with natural berberine hydrochloride (BBH) were investigated toward E. coli and S. aureus by using colony growth on agar plates, bacterial growth curves based on optical densities, and confocal and fluorescence microscopy. Our studies demonstrated that the BBH loaded D-network antibacterial activity was concentration dependent and significantly exceeded that of free BBH. FE-SEM observation confirmed that E. coli and S. aureus can directly contact the D-networks and confocal and fluorescence microscopy showed that free BBH was only very poorly internalized, while the BBH released from the BBH-loaded D-network could be internalized efficiently into bacterial cells, resulting in an increment of the intracellular BBH level compared with the free BBH group. Time-dependent antibacterial activity was observed and it was found that the BBH-loaded D-network dispersion at the BBH dosage of 600 μg mL^-1 almost completely suppressed the growth of E. coli, leading to a viability loss of up to 98.45 ± 1.22%, while the BBH-loaded D-network dispersion at the BBH concentration of 250 μg mL^-1 exhibited a growth inhibition of 97.81 ± 0.83% toward S. aureus over three days. Our results suggest that supramolecular organoclay networks, in the future, may function as promising antibacterial drug carrier systems to promote BBH delivery in E. coli and S. aureus, which can reduce the environmental risk of antibiotics.

Cellulose nanofiber induced self-assembly of zinc oxide nanoparticles: Theoretical and experimental study on interfacial interaction

In-depth understanding of interfacial behavior between biopolymer and semiconductor metal oxides is crucial to developing potential applications of their composites. A structure-ordered cellulose/zinc oxide composite was synthesized and systematically examined by a relativistic density functional theory. The prepared composite shows a hierarchical structure. ZnO nanoparticles of around 30 nm in size are found to uniformly grow along the cellulose fiber, which together construct the primary-structure unit. Associated with experimental characterizations, calculations unravel that the electrostatic attraction between cellulose and ZnO is the main driving force to form the primary structure and the subsequent electron transfer from cellulose to ZnO enhances their interfacial interaction; moreover, an exothermic process was computed. The interfacial interaction is mainly contributed by Zn-O_c (O_c denotes the cellulose oxygen atom), which is intrinsically of a dative bond; the interaction was calculated between -1.39 and -1.83 eV in strength and dominated by orbital attractions.

Ultrasonic irradiation to modify the functionalized bionanocomposite in sulfonated polybenzimidazole membrane for fuel cells applications and antibacterial activity

In this article the new proton exchange membranes were prepared from sulfonated polybenzimidazole (s-PBI) and various amounts of sulfonated titania/cellulose nanohybrids (titania/cellulose-SO₃H) via ultrasonic waves. The ultrasonic irradiation effectively changes the rheology and the glass transition temperature and the crystallinity of the composite polymer. Ultrasonic irradiation has a very strong mixing and dispersion effect, much stronger than conventional stirring, which can improve the dispersion of titania/cellulose-SO₃H nanoparticles in the polymer matrix. The strong -SO₃H/-SO₃H interaction between s-PBI chains and titania/cellulose-SO₃H hybrids leads to ionic cross-linking in the membrane structure, which increases both the thermal stability and methanol resistance of the membranes. After acid doping with phosphoric acid, s-PBI/titania/cellulose-SO₃H nanocomposite membranes exhibit depressions on methanol permeability and enhancements on proton conductivity comparing to the pristine s-PBI membrane. The chemical structure of the functionlized titania was characterized with FTIR, and energy-dispersive X-ray. Imidazole and sulfonated groups on the surface of modified nanoparticles forming linkages with s-PBI chains, improved the compatibility between s-PBI and nanoparticles, and enhanced the mechanical strength of the prepared nanocomposite membranes. From SEM and TEM analysis could explain the homogeneous dispersion of titania/cellulose-SO₃H in nanocomposite membranes. Moreover, the membranes exhibited excellent antibacterial activities against S. aureus and E. coli. A.

The preparation and antibacterial activity of cellulose/ZnO composite: a review

The infectious diseases caused by various bacteria pose serious threat to human health. To solve this problem, antibacterial agents have been widely used in people’s daily life to deactivate or kill these bacteria. Among the antibacterial agents, ZnO is one of the most promising metal oxide antibacterial agents due to its non-toxic nature and safe properties. To expand its application, many composites of ZnO have been widely studied. Cellulose, as one of the most abundant biopolymers, has many merits like biodegradability, biocompatibility and low cost. Thus, many studies focus on synthesized cellulose/ZnO. The synthetic strategy includes both chemical and physical methods. Many of them have been shown that cellulose/ZnO composites have excellent antibacterial activity and are environment-friendly and have many applications for example food packing, antibacterial fibers and so on. This review mainly discusses the preparation methods of cellulose/ZnO and their effect on the morphology and properties.

“Click-chemical” modification of cellulose acetate nanofibers: a versatile platform for biofunctionalization

We demonstrated a platform for the biofunctionalization of cellulose acetate nanofibers using a new type of click chemistry, namely “sulfur(vi)–fluoride exchange reaction”.

Production and characterization of cellulose acetate - titanium dioxide nanotubes membrane fraxiparinized through polydopamine for clinical applications

The present paper introduces a study on the preparation and characterization of cellulose acetate - TiO₂ nanotubes membrane. In order to be used as a hemodialysis membrane, fraxiparinized nanotubes have been incorporated into the cellulose matrix. Fraxiparine embedding was performed via strong binding ability of dopamine. Composite membrane was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle measurement. Electrochemical impedance spectroscopy was used to correlate the morphology of composite membrane with its electrochemical properties. Mott-Schottky test proved titanium dioxide semiconductor incorporation in composite membrane. Permeation test was made to determine pure water flux. The obtained results showed that addition of nanotubes had a positive impact on membrane permeation compared with a control polymeric membrane.