Cellulose Filter Paper Research Articles

Humidity sensor based on cobalt Chloride/Cellulose Filter-Paper for respiration monitoring

With the spread of COVID-19, more and more attention has been paid to the self-monitoring of healthy breathing. In this paper, we propose a humidity sensor which is simple to manufacture, low cost, good flexibility and visualization. The humidity sensor based on cellulose filter paper (FP) exhibited a good moisture-dependent voltage response over a wide relative humidity (RH) range due to the capillary structure of porous cellulose films and highly hydrophilic material of cobalt chloride (CoCl 2 ), which facilitated water molecule adsorption and diffusion. The cellulose film colour shifted from blue to red when RH changed from 11% to 98%, and this colour shift was reversible. A moisture-driven sensor, based on the diffusive flow of water in cellulose networks, can provide an output voltage of 200 mV in a highly moist environment. Due to the high flexibility of cellulose fibres, the sensor maintained a constant output voltage even after 3000 folds. Moreover, the device was successfully applied for human respiratory monitoring and movement frequency tracking. The uniqueness of this new wearable humidity sensor technology can establish a new application field for the development of intelligent textiles and personal health products in the future Internet-of-things.

Carbon-Dots-Initiated Photopolymerization: An In Situ Synthetic Approach for MXene/Poly(norepinephrine)/Copper Hybrid and its Application for Mitigating Water Pollution.

The current work presents a facile and green synthesis of carbon quantum dots (C-dots), which could serve as initiators for polymerization. Herein, C-dots have been synthesized from an easily available green herb, dill leaves, by a single-step hydrothermal method. These C-dots were efficiently utilized as initiators for the photopolymerization of the polymer poly(norepinephrine) (PNE) for the first time. The photopolymerization is discussed by a factorial design, and the optimized synthesis conditions were evaluated by a third-order regression model of three reaction parameters: monomer concentration, C-dots concentration, and UV exposure time. The sign convention of the factorial design mode indicated that monomer concentration and time of exposure are the most important factors for polymerization. The photopolymerized poly(norepinephrine) was extensively studied using Fourier transform infrared (FTIR) analysis, X-ray photoelectron spectroscopy (XPS), mass spectra, scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurement, and thermogravimetric analysis (TGA). UV-assisted deposition of PNE on six different types of substrates was performed, and their water contact angle and surface morphology were studied to evaluate the coating. This UV-triggered polymerization technique was further applied to fabricate sandwich-like composite catalyst MXene/poly(norepinephrine)/copper nanoparticles. This catalyst displayed good performance in the reduction of 4-NP (4-nitrophenol) at ambient temperature, and the first-order rate constant of the catalysis was 9.39 × 10-3 s-1. The reusability of the catalyst was evaluated in terms of the conversion factor. After 10 catalytic cycles, the conversion to catalyze 4-NP was still greater than 91%. The catalytic performance was also evaluated in the continuous flow condition through a membrane, fabricated from a cellulose filter paper coated with MXene/poly(norepinephrine)/copper nanoparticles. This composite catalyst not only offers a practical mode for the catalytic reaction of MXene-based materials but also lays down the foundation for the development of new catalysts.

Tannic Acid-chitosan Strengthened Cellulose Filter Paper for Water Disinfection via Formation of Silver Nanoparticles

Tannic Acid-chitosan Strengthened Cellulose Filter Paper for Water Disinfection via Formation of Silver Nanoparticles

Transport of chlorinated paraffins (CPs) from baking oven doors into the food

Chlorinated paraffins (CPs) have been repeatedly detected in the kitchen environment. Especially baking ovens were contaminated with high CP amounts on the insides of the doors. To investigate if CPs could be transferred into baked food, we spiked self-synthesized single chain C12-CP and C15-CP standards onto the inside door of an unused, CP-free baking oven. Experiments were performed under different conditions to assess possible CP transportation pathways. Coconut fat was used as food simulant, the exhaust air was monitored with cellulose filter paper and remaining CPs were collected via cotton wipes. In all experiments, both C12- and C15-CPs could be identified in both the food simulant and the cellulose samplers. Mean transfer rates into the food simulant amounted to 2.2% for C12-CPs and 5.8% for C15-CPs. Baking of food in CP-containing baking ovens may perceptibly increase the CP intake of consumers.

Unmodified cellulose filter paper, a sustainable and affordable sorbent for the isolation of biogenic amines from beer samples

While current trends in Green Analytical Chemistry aim at reducing or simplifying sample treatment, food usually comprises complex matrices where direct analysis is not possible in most cases. In this context, sample treatment plays a pivotal role. Biogenic amines are naturally formed in many foodstuffs due to the action of microorganisms, while their presence has been associated with adverse health effects. In this work, the extraction of seven biogenic amines (cadaverine, histamine, phenylethylamine, putrescine, spermidine, spermine, and tyramine) from beer samples has been simplified using laboratory filter paper as sorbent without any further modification. The analysis of the eluates by direct infusion mass spectrometry reduces the time of analysis, increasing the sample throughput. This simple but effective method enabled the determination of the analytes with limits of detection as low as 0.06 mg L−1 and relative standard deviations better than 11.9%. The suitability of the method has been assessed by analyzing eight different types of beers by the standard addition method.

Partially carbonized cellulose filter paper as a green adsorbent for the extraction of pesticides from fruit juices

In this study, a new solid phase extraction method based on the use of a low-cost funnel-shaped partially carbonized cellulose filter paper as a sorbent has been developed. The sorbent is easily prepared by heating the folded filter paper wetted with sulfuric acid solution and can be reused for several times. It is combined with dispersive liquid–liquid microextraction and used for the extraction of some pesticide residues from fruit juice samples prior to their analysis by gas chromatography–flame ionization detection. In this work, limits of detection and quantification were in the ranges of 0.30–0.61 and 1.0–2.0 µg L−1, respectively, and relative standard deviations ranged between 3 and 6% for intra– (n=5) and inter–day (n=5) precisions at a concentration of 25 µg L−1 of each pesticide. The enrichment factors of 452–751 were achieved. Extraction recoveries were in the range of 45–75%. The calibration curves had wide linear ranges with a good linearity (coefficient of determination ≥ 0.994). Finally, efficiency of the method was apprised by determining the analytes in fruit juice samples and relative recoveries were found to be in the range of 85–101%.

Copper on chitosan-modified cellulose filter paper as an efficient dip catalyst for ATRP of MMA

Achieving an efficient catalyst in the ATRP system with a simple design, preparation from available materials, and high recyclability is a significant challenging issue. To attain the goal, herein, we used chitosan (CS)-modified cellulose filter paper (FP) as a green support for the synthesis of dip catalyst. The preparation of this catalyst involved surface treatment of the FP strips by CS coating through a dipping method, which increased the affinity of the substrate for adsorbing copper ions in the next step. The Cu@CS-FP catalyst was prepared without the requirement of any ligands. The synthesized dip-catalyst, in the form of the strips, was employed for the first time in the ATRP reaction of methyl methacrylate to assay catalytic activity. Catalytic insertion/ removal (ON/OFF) experiments were carried out during the polymerization. A reasonable control over the molecular weight with high conversion (68%) and polydispersity index of 1.32 under mild reaction conditions were obtained. Significantly, because of the facile separation of the catalyst, the amount of copper that remained in the polymer was very low (2.7 ppm). Also, the recyclability of the catalyst was investigated for five runs. The conversion in the final run was 64% without a loss of catalyst efficiency.

Bionanoparticles from Moringa as Antimicrobial Activity and It’s Application in Water Purification: Thesis Abstract

Thesis Abstract Background: Nanotechnology is the greatest promising technique for generating new applications in water purification. Green synthesis of silver nanoparticles and copper oxide nanoparticles is an eco-friendly, cheap and non-toxic more than chemical and physical methods. Aim: This study focuses on green synthesis, characterization, antibacterial activities of silver nanoparticles and copper oxide nanoparticles synthesized using Moringa oleifera leaf and stem extract and its application in water purification. Materials and Methods: The green synthesis of silver nanoparticles was done by using Moringa oleifera leaf and stem extract and 1mM of silver nitrate solution while copper oxide nanoparticles were synthesized by using Moringa oleifera leaf and stem extract and 10mM of copper sulfate pentahydrate solution. pH, temperature and the mixture reaction time are parameters affecting the formation of silver nanoparticles and copper oxide nanoparticles. Results: In this study, various techniques and devices used to characterize and confirms the formation of silver nanoparticles and copper oxide nanoparticles included visual observation, UV-Vis spectroscopy, TEM, FTIR, and EDX. Silver nanoparticles and copper oxide nanoparticles showed antimicrobial activity against E. coli ATCC 8739 and S. typhi ATCC 14028 and isolated microorganisms from tested water sample which included Pseudomonas aeruginosa and Klebsiella variicola. Cellulose filter paper which coated with silver nanoparticles and copper oxide nanoparticles showed good effect in water purification as its good antimicrobial activity against microorganisms, increasing pH value and reducing conductivity, total alkalinity values and Pb concentration value. Conclusion: The results from this study indicate that bio-nanoparticles from moringa have an antimicrobial activity that can be applied in water Purification

Dissemination of Aerosol and Splatter in Clinical Environment during Cavity Preparation: An In Vitro Study.

Dental health care workers around the world are in a constant state of fear and anxiety because they work in a constrained space of the dental practice. During routine dental procedures, they are exposed to aerosol and splatter. These airborne particles pose a great risk of transmitting contagious infections to health care workers and patients, especially in an era of social distancing due to COVID-19. The current study was conducted to evaluate contamination amount, duration, the distance of aerosol, and splatter produced after cavity preparation using a two-hole and four-hole handpiece. The study was performed on a dental manikin in a dental simulation laboratory at the College of Dentistry, King Faisal University Al Ahsa. The dental manikin was set to a reclined position to simulate the clinical operatory position of the patient for dental restorative procedures. Aerosol and splatter were collected on Grade 1 qualitative cotton cellulose filter paper. These were placed on adhesive tape extending from the headrest of the dental manikin in six different directions (2, 4, 6, 8, 10, and 12 o’clock) for up to 60 inches and on certain positions of the operator and assistant such as the chest, head, forearms, upper leg, and inside facemask. Class V cavity preparation was done by the principal investigator at a specific time of 3 min on tooth #11 using a two-hole high-speed handpiece, then on the next day, Class V cavity preparation was performed on tooth #21 by a four-hole handpiece. High volume suction was used throughout the cavity preparation. Immediately after cavity preparation, the first filter paper disc was replaced with new ones in all positions. The second set of filter papers was removed after 30 min. Transparent grids were used to count the contamination area on the filter paper disc. No statistically significant difference was found in the mean amount of aerosol and splatter produced by both handpieces, however, a statistically significant difference was found in an amount of aerosol and splatter produced at a 12, 24, and 36 inches distance immediately after cavity preparation and 30 min after cavity preparation, regardless of the type of handpiece used. It is advisable to refrain from removing the personal protective barriers immediately after the procedure within the vicinity of the dental practice. The use of other adjuncts such as high volume suction to reduce the spread of aerosol and splatter is also recommended.

Superhydrophobic and Flexible Silver Nanowire-Coated Cellulose Filter Papers with Sputter-Deposited Nickel Nanoparticles for Ultrahigh Electromagnetic Interference Shielding.

Superhydrophobic, flexible, and ultrahigh-performance electromagnetic interference (EMI) shielding papers are of paramount importance to safety and long-term service under external mechanical deformations or other harsh service environments because they fulfill the growing demand for multipurpose materials. Herein, we fabricated multifunctional papers by incorporating sputter-deposited nickel nanoparticles (NiNPs) and a fluorine-containing coating onto cellulose filter papers coated with silver nanowires (AgNWs). AgNW networks with sputter-deposited NiNPs provide outstanding magnetic properties, electrical conductivity, and EMI shielding performance. At an AgNW content of 0.109 vol % and a NiNP content of 0.013 mg/cm2, the resultant papers exhibit a superior EMI shielding effectiveness (SE) of 88.4 dB. Additionally, the fluorine-containing coating endows the resultant papers with a high contact angle of 149.7°. Remarkably, the obtained papers still maintain a high EMI SE even after 1500 bending cycles or immersion in water, salt, or strong alkaline solutions for 2 h, indicating their outstanding mechanical robustness and chemical durability. This work opens a new window for designing and implementing ultrahigh-performance EMI shielding materials.

Video-based fractional order identification of diffusion dynamics for the analysis of migration rates of polar and nonpolar liquids: Water and oil studies.

Diffusion dynamics of water and oil are observed in real-time using video images. Savitzky-Golay derivative filtering ensures accurate localization of the liquid front. System identification demonstrates that a fractional-order model with only two parameters may be used to describe the dynamics of the diffusion process. The method paves the way for video-based cellulose filter paper microfluidics and lateral flow assays, which are low cost and have broad diagnostic applications.

Well-Dispersed Silver Nanoparticles on Cellulose Filter Paper for Bacterial Removal.

In this study, a polydopamine (PDA) and polyethyleneimine (PEI)-assisted approach was developed to generate well-distributed PDA/PEI/silver (PDA/PEI/Ag) nanocomplexes on the surfaces of commercial cellulose filter papers to achieve substantial bacterial reduction under gravity-driven filtration. PDA can bind to cellulose paper and act as a reducer to produce silver nanoparticles (AgNPs), while PEI can react with oxidative dopamine and act as a dispersant to avoid the aggregation of AgNPs. The successful immobilization of PDA/PEI/Ag nanocomplexes was confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were used as pathogen models to test the efficacy of the PDA/PEI/Ag nanocomplex-incorporated filter papers. The PDA/PEI/Ag nanocomplex-incorporated filter papers provided a substantial bacterial removal of up to 99% by simple gravity filtration. This work may be useful to develop a feasible industrial production process for the integration of biocidal AgNPs into cellulose filter paper and is recommended as a local-condition water-treatment technology to treat microbial-contaminated drinking water.

Dopamine-polyethyleneimine co-deposition cellulose filter paper for α-Glucosidase immobilization and enzyme inhibitor screening

In this work, cellulose filter paper (CFP), which is inexpensive and commercially available, was used as the carrier, and the immobilized α-glucosidase was obtained by two steps: firstly, the surface of CFP was modified by polydopamine/polyethyleneimine (PDA/PEI) co-deposition method to obtain CFP-PDA/PEI with a uniform coating of rich positive charge; subsequently, α-glucosidase was immobilized on the CFP-PDA/PEI by electrostatic adsorption. The free enzyme and immobilized enzyme have the same optimal temperature (70℃) and pH (8.0), and their Km is similar, which is 2.2 and 2.8, respectively. These results show that the immobilization process does not change the properties of the enzyme greatly. The immobilized enzyme still maintains 75.6% of its initial activity after 10 repeated uses, showing good reusability. The excellent repeatability (RSD = 2.2%, n = 5) and the verification of competitive inhibitor (acarbose) illustrates the reliability of the immobilized enzymes for enzyme inhibitor screening. Finally, combined with CE, a screening method based immobilized α-glucosidase was proposed and applied to screen the α-glucosidase inhibitory from 10 kinds of Traditional Chinese medicines (TCMs) in vitro. The results indicated that the method was a very effective tool for screening potential α-glucosidase inhibitors from TCMs.

A Cellulose Paper-Based Fluorescent Lateral Flow Immunoassay for the Quantitative Detection of Cardiac Troponin I.

This paper presents a lateral flow assay (LFA) for the quantitative, fluorescence-based detection of the cardiac biomarker troponin I (cTnI) that features an analytical strip made of cellulose filter paper. The results show that the wicking and test time are comparable to those obtained with conventional nitrocellulose (NC)-based LFAs. Further, the cellulose paper provides an excellent background with no auto-fluorescence that is very adequate in detecting fluorescent lines. While fluorescence that was generated with cellulose strips was lower when compared to that generated in NC strips, signals could be improved by layering carbon nanofibers (CNF) on the cellulose. A nonlinear behavior of the concentration–response relationship was observed for the LFA architectures with NC, cellulose, and cellulose-CNF in the 0 to 200 ng/mL cTnI concentration range. The measurements were consistent and characterized by coefficients of variation lower than 2.5%. Detection and quantitation limits that were in the range 1.28–1.40 ng/mL and 2.10–2.75 ng/mL were obtained for LFA with cellulose and cellulose CNF strips that are equivalent to the limits obtained with the standard NC LFA. Overall, we showed that commercially available filter paper can be used in the analytical strip of LFA.

Simple approach to fabricate MXene/cellulose paper for electromagnetic interference shielding applications

AbstractA simple approach was developed to fabricate high‐performance MXene/cellulose (MC)‐based electromagnetic interference (EMI) shielding papers. The oriented MXene sheets located on one side of cellulose filter paper construct a continuous conductive layer, endowing the MC paper with high electrical conductivity (240.1 S/m) and excellent EMI shielding effectiveness (29.3 dB for 0.192‐mm thickness) at an MXene content of 0.72 vol%. Moreover, the EMI shielding effectiveness of four stacked MC papers reached 40.5 dB. This result means that 99.9911% of the microwave radiation is attenuated, and 0.0089% is transmitted, through the four‐piece MXene/cellulose filter papers. Therefore, MC paper has promising properties for excellent EMI shielding materials in current electronic devices.

Evaluation and application of an efficient plant DNA extraction protocol for laboratory and field testing.

Nucleic acids in plant tissue lysates can be captured quickly by a cellulose filter paper and prepared for amplification after a quick purification. In this study, a published filter paper strip method was modified by sticking the filter paper on a polyvinyl chloride resin (PVC) sheet. This modified method is named EZ-D, for EASY DNA extraction. Compared with the original cetyl trimethylammonium bromide (CTAB) method, DNA extracted by EZ-D is more efficient in polymerase chain reaction (PCR) amplification due to the more stable performance of the EZ-D stick. The EZ-D method is also faster, easier, and cheaper. PCR analyses showed that DNA extracted from several types of plant tissues by EZ-D was appropriate for specific identification of biological samples. A regular PCR reaction can detect the EZ-D-extracted DNA template at concentration as low as 0.1 ng/μL. Evaluation of the EZ-D showed that DNA extracts could be successfully amplified by PCR reaction for DNA fragments up to 3000 bp in length and up to 80% in GC content. EZ-D was successfully used for DNA extraction from a variety of plant species and plant tissues. Moreover, when EZ-D was combined with the loop-mediated isothermal amplification (LAMP) method, DNA identification of biological samples could be achieved without the need for specialized equipment. As an optimized DNA purification method, EZ-D shows great advantages in application and can be used widely in laboratories where equipment is limited and rapid results are required.

An antibody-free liver cancer screening approach based on nanoplasmonics biosensing chips via spectrum-based deep learning

The clinical needs of rapidly screening liver cancer in large populations have asked for a facile and low-cost point-of-care testing (POCT) method. We present a nanoplasmonics biosensing chip (NBC) that would empower antibody-free detection with simplified analysis procedures for POCT. The cheaply fabricable NBC consists of multiple silver nanoparticle-decorated ZnO nanorods on cellulose filter paper and would enable one-drop blood tests through surface-enhanced Raman spectroscopy (SERS) detection. In this work, utilizing such an NBC and deep neural network (DNN) modeling, a direct serological detection platform was constructed for automatically identifying liver cancer within minutes. This chip could enhance Raman signals enough to be applied to POCT. A classification DNN model was established by spectrum-based deep learning with 1140 serum SERS spectra in equal proportions from hepatocellular carcinoma (HCC) patients and healthy individuals, achieving an identification accuracy of 91% on an external validation set of 100 spectra (50 HCC versus 50 healthy). The intelligent platform, based on the biosensing chip and DNN, has the potential for clinical applications and generalizable use in quickly screening or detecting other types of cancer.

Cellulose acetate/fiber paper composite membrane for separation of an oil-in-water emulsion

The cellulose composite membrane combines the advantages of cellulose acetate and cellulose filter paper with good antifouling performance and excellent mechanical properties.

Robust immobilization of anionic silver nanoparticles on cellulose filter paper toward a low-cost point-of-use water disinfection system with improved anti-biofouling properties.

Silver nanoparticle (AgNP)-decorated cellulose filter paper (FP), a low-cost point-of-use (POU) water disinfection system, can supply affordable and safe drinking water for people in desperate need, especially in rural areas in developing countries. However, owing to the unstable immobilization of AgNPs, silver can leach into the treated drinking water from the FP and exceed the World Health Organization (WHO) drinking water limit (<100 μg L−1), which is a potential threat to both human health and the environment. In this work, in order to robustly immobilize anionic silver nanoparticles (GA@AgNPs), we facilely prepared lipoic acid-modified cellulose filter paper (LA-FP), in which GA@AgNPs were robustly immobilized onto filter paper (GA@AgNPs-LA-FP) by strong chelation via the disulfide bond of LA with the surface of the silver nanoparticles. GA@AgNPs-LA-FP exhibited both excellent bacterial anti-adhesion activity and strong bactericidal activity, which can synergistically mitigate biofouling by inhibiting biofilm formation on the paper surface. Moreover, employed as a gravity-driven bactericidal filter, the GA@AgNPs-LA-FP membrane treated 100 mL of river water within 10 min, and the resulting water quality met the WHO drinking water standards, indicating this material's practical application for POU water disinfection.

Nanofiltration filter paper based on multi-walled carbon nanotubes and cellulose filter papers.

Air filter paper with a high filtration efficiency that can remove small-size pollutant particles and toxic gases is vital for human health and the environment. We report a nanofiltration paper that is based on wood fiber filter paper with good mechanical properties and a three-dimensional network structure. The filter paper was prepared by impregnation with multi-walled carbon nanotubes (MWCNTs) and phenol-formaldehyde (PF). The results showed that MWCNTs were present on the surfaces of the fibers and between the pores, which increased the specific surface area of the fibers and enhanced the effective interception of the particles. The optimum impregnation concentration of the MWCNT was 0.1%. Compared with the cellulose fibers (CFs), the average pore diameter of the 0.1% MWCNT–CF filter paper was reduced by 8.05%, the filtration efficiency was increased by 0.64%, and the physical properties were slightly enhanced. After impregnation with PF, the mechanical properties of the air filter paper were significantly enhanced. The PF on the fiber surfaces and at the junction of the fibers covered the MWCNTs. Based on the change in the filter paper properties after impregnation, the optimal filter paper strength index and filtration performance were observed at a solid PF content of 8.4%.