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1.
Anal Chim Acta ; 1208: 339844, 2022 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-35525581

RESUMO

In this paper, simultaneous enrichment and separation of ions and amphoteric components were successfully demonstrated by using electric field (E) and pH gradient (double gradient) in the ion depletion zone of anion concentration polarization interface established on a paper fluid channel. Experimental results were visualized with colored ions (bright blue and amaranth) and protein probes (phycocyanin and cytochrome C). With optimization, colored phycocyanin and bovine hemoglobin with similar pI as that of albumin and immunoglobulin respectively were well separated in 900 s with 10-fold enrichment effect. Based on the separation and enrichment function of this paper-based analytical device (PAD) and rapid selective staining of human serum albumin (HSA) with bromophenol blue, a rapid colorimetric detection of HSA was implemented with smartphone camera. A limit of detection (LOD) of 5.2 mg·L-1 was achieved in the clinically significant range of 10-300 mg·L-1 (R2 = 0.99). This method was applied to real human urine samples with good agreement (ɑ = 0.01) to clinical detection method (immunoturbidimetry). With the separation and enrichment functions of PAD, both the specificity and sensitivity were enhanced, which provides a solid basis for point-of-care test of microalbuminuria. Therefore, this PAD device is potential for sample pretreatment and detection of target components from complex physiological samples.


Assuntos
Colorimetria , Ficocianina , Colorimetria/métodos , Humanos , Íons , Limite de Detecção , Papel , Albumina Sérica Humana/urina , Smartphone
2.
Carbohydr Polym ; 288: 119371, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35450633

RESUMO

Herein, a facile strategy was proposed for preparing a high-strength and super-hydrophobic packaging paper with improved moisture and air barrier properties, which was derived from cellulosic pulps, micro-fibrillated cellulose (MFC), and nano-silica (n-SiO2). Owning to the laminated process followed by spraying approach, MFC and n-SiO2 were assembled onto two surfaces of the cellulose paper base, respectively, endowing the mechanical behaviors and superhydrophobic performance of this biodegradable composite papers as packaging material. The as-obtained multilayered papers demonstrated impressive dry tensile strength and remarkable wet tensile strength of 6542.5 N/m and 5875 N/m, which were increased by 56% and 2277%, respectively. In addition, the multilayered paper with rational mechanical properties possessed low permeabilities of air (3.17 × 10-3 µm·Pa-1·s-1), oxygen (9.687 cm3·m-2·day-1·atm), and water vapor (378.24 g·m-2·day-1), respectively, as well as a superhydrophobic performance with the contact angle of ~151.2°. Overall, the feasibility of large-scale production of biodegradable packaging materials in the paper-making industry is demonstrated by the fact that the micro/nanostructures and hydrophobic surfaces could be directly constructed on cellulosic paperboard.


Assuntos
Celulose , Dióxido de Silício , Celulose/química , Interações Hidrofóbicas e Hidrofílicas , Papel , Vapor , Resistência à Tração
3.
Bioresour Technol ; 353: 127078, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35395367

RESUMO

The present study aimed to enzymatic deinking of waste papers and to valorize the effluent for biobutanol production. Application of fungal enzymatic cocktail (cellulase, amylase, xylanase, pectinase, lipase, and ligninase) on office used paper, newspaper, and ballpen written paper leading to improvement in brightness (84.91, 72.51, 76.69 % ISO), InKd (82.89, 68.95, 76.49%), κ-number (12.9, 13.6, and 13.1), opacity (27.91, 30.07, and 2.85%), tensile strength (49.24, 45.31, and 46.98 Nm/g), respectively and indices were consistent with chemical treated pulps. The quality of effluent generated during enzymatic deinking in respect to BOD and COD level was eco-friendlier than the chemical process. The enzyme-treated effluent was employed as supporting substrate for butanol (18.4 g/l) production by Clostridium acetobutylicum ATCC824. Material balance and life cycle assessment of the whole processes were evaluated to validate its industrial and environmental relevance.


Assuntos
Celulase , Clostridium acetobutylicum , 1-Butanol , Butanóis , Tinta , Papel
4.
Sensors (Basel) ; 22(8)2022 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-35458878

RESUMO

Microfluidic paper-based analytical devices (µPADs) represent one of the promising green analytical strategies for low-cost and simple determination of various analytes. The actual task is the development of such devices for quantitation of antioxidants, e.g., flavonoids. In this paper, possibilities of a novel three-reagent µPAD including silver nitrate, 4-nitrophenyldiazonium tetrafluoroborate, and iron(III) chloride as reagents are assessed with respect to the determination of dihydroquercetin. It is shown that all the three reagents produce different colorimetric responses that can be detected by a mini-spectrophotometer-monitor calibrator or by a smartphone. The method is applicable to direct measuring high contents of dihydroquercetin (the linearity range is 0.026-1 mg mL-1, and the limit of detection is 7.7 µg mL-1), which is favorable for many dietary supplements. The analysis of a food supplement was possible with the relative standard deviations of 9-26%, which is satisfactory for quantitative and semiquantitative determinations. It was found that plotting a calibration graph in 3D space of the three reagents' responses allows us to distinguish dihydroquercetin from its close structural analogue, quercetin.


Assuntos
Colorimetria , Técnicas Analíticas Microfluídicas , Colorimetria/métodos , Compostos Férricos , Indicadores e Reagentes , Papel , Quercetina/análogos & derivados
5.
Anal Chem ; 94(12): 5132-5139, 2022 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-35293204

RESUMO

Microfluidic paper-based analytical devices (µPADs) are emerging as a prominent platform for disease detection, specifically in developing countries. This paper device offer simplicity and affordability not typically seen in centralized laboratory settings. However, detection limits in µPADs are inadequate and often require test results to be read within a specific time interval to ensure accuracy. To overcome these challenges, we are developing an on-chip mass spectrometry (MS) detection strategy for immunoassays performed on paper substrates. Herein, we present our initial results from a proof-of-concept study toward the development of µPADs capable of storing immunoassay reagents within the confinements of the 3D device, automatic splitting of biofluid into four individual test zones, immuno-capture of the disease biomarker, and on-chip MS detection of the captured species. The reported study encourages the development of point-of-care and direct-to-customer testing using disposable µPADs to collect samples, followed by sensitive analysis using portable MSs. We demonstrate this capability using malaria Plasmodium falciparum histidine-rich protein 2 (PfHRP2) antigen detection.


Assuntos
Malária , Técnicas Analíticas Microfluídicas , Humanos , Imunoensaio/métodos , Malária/diagnóstico , Espectrometria de Massas , Microfluídica , Papel
6.
Biosens Bioelectron ; 207: 114184, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35339073

RESUMO

This study reports an economical and portable point-of-care (POC) monitoring device based on artificial multi-enzyme cascade systems for multiple detection purposes. The device was made up of a disposable three dimensional microfluidic paper-based analytical device (3D µPAD) with multiple detection zones and a smartphone readout. On-paper synthesis of a multifunctional mimetic composite, based on the CeO2 nanoparticles embedded in the amino-functionalized Fe metal-organic frameworks (CeO2@NH2-MIL-88B(Fe)), for cascade reactions was the main achievement of this work. The 3D µPAD was applied for simultaneous quantification of glucose, fructose, sucrose and maltose, and the detection process consisted of the enzymatic reaction of each sugar by anchored enzymes on the metal-organic frameworks (MOF) and successive oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). Utilizing the new artificial mimicking system improved the color development uniformity and resulted in a reliable detection tool, with excellent detection limits in the range of 20-280 µM. It was directly applied to analyze the sugars levels of human total blood, urine, semen, honey and juice samples with the relative errors of less than 7.7% compared with the HPLC method. The cost-effective and easy-to-use µPAD has a great potential to be used in either medical diagnostics or the food industry. Also, it can be considered as a competitive POC method for patients in disadvantaged communities or emergencies.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Nanopartículas , Técnicas Biossensoriais/métodos , Colorimetria , Frutose , Glucose , Humanos , Maltose , Papel , Sacarose
7.
Anal Sci ; 38(5): 759-767, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35344195

RESUMO

The membraneless-gas separation microfluidic paper-based analytical device (ML-GS µPAD), consisting of donor, spacer, and acceptor layers, was developed to monitor total ammonia in fish pond water. The principle of the analysis involved the addition of sodium hydroxide solution to the sample zone in the donor layer containing ammonia/ammonium, and the produced ammonia gas diffuses through the spacer to the detection zone in the acceptor layer containing red rose extract to produce a color change from pink to blue corresponding to the ammonia/ammonium concentration. Under optimum conditions, the proposed method provided good linearity of ammonia in the range concentration of 0-100 mg L-1 (R2 = 0.9993) with LOD and LOQ of 2.25 and 7.51 mg L-1, respectively. This method was successfully applied to fish pond water samples without significant influence of interfering compounds with recoveries in the range of 103-110%, indicating good selectivity and accuracy of the proposed method.


Assuntos
Amônia , Compostos de Amônio , Amônia/análise , Indicadores e Reagentes , Microfluídica , Papel , Lagoas , Água
8.
Bioresour Technol ; 352: 127076, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35351569

RESUMO

The effective degradation of KL from paper mill effluent is an important for environmental safety. This research is primarily concerned with the identification of KL-degrading Bacillus cereus from activated sludge and their possible use for the degradation of Kraft lignin (KL). This strain was involved in the production of lignin peroxidase-LiP (3.20 U/mL), manganese peroxidase-MnP (20.36 U/mL), and laccase (21.35 U/mL) enzymes, which were responsible for high KL degradation (89%) and decolorization (40%) at 1000 mg/L KL in 3 days. The SEM-EDS, UV-Vis, FTIR, and GC-MS analysis were used to analyze the bacterial cell and KL interactions to trace the KL degradation process. The significant reduction of pollutants (KL-72.5%, color-62.0%, COD-45.05%) and reduction in toxicity (80%) of bacterial-treated effluent indicated that B. cereus has the potential to be used in the degradation of pollutants from paper mill effluents.


Assuntos
Poluentes Ambientais , Águas Residuárias , Bacillus cereus/metabolismo , Biodegradação Ambiental , Poluentes Ambientais/análise , Resíduos Industriais/análise , Lignina/metabolismo , Papel , Águas Residuárias/análise
9.
Anal Bioanal Chem ; 414(13): 3959-3970, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35352162

RESUMO

Microfluidic paper-based analytical devices (µPADs) have been widely used in point-of-care testing owing to their simple operation, low volume of the sample required, and the lack of the need for an external force. To obtain accurate semi-quantitative or quantitative results, µPADs need to respond to the challenges posed by differences in reaction conditions. In this paper, multi-layer µPADs are fabricated by the imprinting method for the colorimetric detection of C-reactive protein (CRP). Different lighting conditions and shooting angles of scenes are simulated in image acquisition, and the detection-related performance of µPADs is improved by using a machine learning algorithm. The You Only Look Once (YOLO) model is used to identify the areas of reaction in µPADs. This model can observe an image only once to predict the objects present in it and their locations. The YOLO model trained in this study was able to identify all the reaction areas quickly without incurring any error. These reaction areas were categorized by classification algorithms to determine the risk level of CRP concentration. Multi-layer perceptron, convolutional neural network, and residual network algorithms were used for the classification tasks, where the latter yielded the highest accuracy of 96%. It has a promising application prospect in fast recognition and analysis of µPADs.


Assuntos
Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas , Proteína C-Reativa , Aprendizado de Máquina , Papel
10.
Anal Chim Acta ; 1199: 339588, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35227387

RESUMO

Low cost and user-friendly paper microfluidic devices, combined with DNA-based biosensors with binding capacities for specific molecules, have been proposed for the developing of novel platforms that ease and speed-up the process of cell secretion monitoring. In this work, we present the first cellulose microfluidic paper-based analytical device for the single-step detection of cell secreted Vascular Endothelial Growth Factor through a self-reporting Structure Switching Signaling Aptamer. A three-part Structure Switching Signaling Aptamer was designed with an aptameric sequence specific for VEGF, which provides a quantifiable fluorescent signal through the displacement of a quencher upon VEGF recognition. The VEGF biosensor was integrated in cellulose paper, enabling the homogenous distribution of the sensor in the paper substrate and the detection of as low as 0.34 ng of VEGF in 30 min through fluorescence intensity analysis. As a proof-of-concept, the biosensor was incorporated in a microfluidic paper-based analytical device format containing a VEGF detection zone and a control zone, which was applied for the detection of cell secreted VEGF in the supernatant of mesenchymal stem cells culture plates, demonstrating its potential use in cell biology research.


Assuntos
Técnicas Biossensoriais , Células-Tronco Mesenquimais , Técnicas Analíticas Microfluídicas , Microfluídica , Papel , Fator A de Crescimento do Endotélio Vascular/análise , Fatores de Crescimento do Endotélio Vascular
11.
Sci Justice ; 62(2): 221-228, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35277236

RESUMO

It is well established that a large proportion of paper banknotes in circulation contain traces of cocaine. Being able to discriminate between the innocent transfer of illicit drug particles acquired through everyday interactions with surfaces such as banknotes, as opposed to transfer resulting from criminal activities can provide valuable intelligence that can inform an investigation. With many countries adopting polymer banknotes as legal tender, it is important to consider the transfer of cocaine from these surfaces as well as the retention of these particulates on polymer banknotes for evaluative interpretation in crime reconstruction. This comparison study assessed three contact variables (force, time, and rotation) on the transfer of cocaine particulates from paper and polymer banknotes onto a human skin proxy. The persistence of cocaine particulates was assessed through a realistic scenario which mimicked a cash transaction. Quantifiable amounts of cocaine were transferred onto the human skin proxy across all of the contacts assessed, with a greater transfer observed with contacts involving polymer banknotes and those contacts which involved rotation. Following extensive handling, cocaine persisted on both banknote types, with paper banknotes retaining larger amounts of cocaine than polymer banknotes. These findings show that cocaine can persist on both paper and polymer banknotes for extended periods of time following handling and is therefore available for transfer. This transfer then readily occurs, even when contact is brief and involves relatively small forces. A key distinction between the banknote types was that cocaine particulates are more likely to transfer from polymer banknotes due to the lower retention rate of particulates on this surface. Such insights can aid in evaluating the relevance of illicit drug particles identified on items or persons of interest in crime reconstruction approaches.


Assuntos
Cocaína , Drogas Ilícitas , Humanos , Papel , Polímeros
12.
Sci Rep ; 12(1): 3427, 2022 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-35236904

RESUMO

A one-step analysis method was developed for four types of amino acids using a microfluidic paper-based analytical device fabricated from chromatography filtration paper and laminate films. Aminoacyl-tRNA synthetase was used to detect each amino acid. The obtained laminated paper-based analytical device (LPAD) contained four enzymatic reaction areas. Colorimetric detection was performed based on the molybdenum blue reaction. A model method for the simple, easy, and simultaneous detection of several amino acid concentrations was suggested, in contrast to the conventional methods such as HPLC or LC-MS. The method provided a selective quantification at the ranges of 3.6-100 µM for tryptophan, 10.1-100 µM for glycine, 5.9-100 µM for histidine and 5.6-100 µM for lysine with a detection limit of 1.1 µM, 3.3 µM, 1.9 µM and 1.8 µM, respectively. LPAD fabrication was considerably simple, and the subsequent detection process was easy and required a short period of time (within 15 min).


Assuntos
Aminoacil-tRNA Sintetases , Técnicas Analíticas Microfluídicas , Aminoácidos , Aminoacil-tRNA Sintetases/química , Histidina/análise , Dispositivos Lab-On-A-Chip , Microfluídica , Papel
13.
Anal Methods ; 14(10): 1069-1076, 2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35195618

RESUMO

This study develops a simple and low-cost 3D paper-based analytical device (3D PAD) for the detection of available phosphate in soil. Epoxy resin is presented as a new hydrophobic material for low-cost mass production of PADs using the screen-printing method. An optimized concentration of epoxy resin solution is screen printed onto Whatman filter paper no. 1 in an easy one-step process to create hydrophobic patterns on PADs. The epoxy resin is air dried at room temperature, without heating or UV curing. This method delivers high reproducibility, resolution, and stability, and the epoxy resin barrier is compatible with both organic solvents and aqueous solutions. The molybdenum blue method is used in this PAD to measure phosphate in a colorimetric assay. The developed 3D PAD attains a linear range of 0.5-40 mg L-1, with a limit of detection (LOD) of 0.25 mg L-1, and a limit of quantitation (LOQ) of 0.83 mg L-1. The relative standard deviation of intra-day measurements is 1.52-2.46%, and the inter-day standard deviation is 1.89-2.74%, indicating satisfactory reproducibility. This 3D PAD was tested for its ability to detect phosphate in a variety of actual soil samples and the results were validated against spectrophotometric analysis using a paired t-test, which showed high accuracy. In short, the new analytical device described in this study is simple, fast, and inexpensive to make and use, providing a versatile phosphate detection tool for many soil types, even in situations when resources are limited.


Assuntos
Resinas Epóxi , Papel , Fosfatos , Reprodutibilidade dos Testes , Solo
14.
Bioprocess Biosyst Eng ; 45(4): 741-747, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35113232

RESUMO

In the current study, pretreatment of sugarcane bagasse has been carried out with ultrafiltered xylano-pectinolytic enzymes, before conventional chemical bleaching process. Optimized enzymatic dose (4 IU xylanase and 1.2 IU pectinase per g of oven dried pulp) and retention time (180 min) were determined on the basis of maximum decrement in kappa number (from 20.93 to 15.32), release of maximum sugars (7.4 mg/g) as well as attainment of maximum brightness (25.1% ISO), whiteness (from - 57.3 to - 41.9) and minimum yellowness (from 48.7 to 35.3) of the pulp samples. Enzymatically treated samples also showed release of phenolic, lignin and hydrophobic compounds in their filtrates. Nearly 30% decrement in the exhaustion of bleaching chemical dose was detected as compared to control samples. The physical properties such as tear index, burst index, double fold number, breaking length, gurley porosity and viscosity of enzymo-chemically treated bagasse pulp samples were improved by 6.68%, 33.86%, 22.92%, 13.43%, 17.5% and 9.64%, respectively. Additionally, a decrement of 36.75% and 28.29% in the values of BOD and COD of the effluents was also noted, which demonstrated the fact that, inclusion of enzymes in chemical based protocols of paper and pulp industries could be a highly beneficial and eco-friendly approach in upcoming decades. This is the first report mentioning the effect of ultrafiltered xylano-pectinolytic enzymes concoction on sugarcane bagasse pulp.


Assuntos
Saccharum , Celulose , Papel , Poligalacturonase
15.
Ther Innov Regul Sci ; 56(3): 394-404, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35142989

RESUMO

BACKGROUND: Visual analogue scales (VASs) are used in a variety of patient-, observer- and clinician-reported outcome measures. While typically included in measures originally developed for pen-and-paper completion, a greater number of clinical trials currently use electronic approaches to their collection. This leads researchers to question whether the measurement properties of the scale have been conserved during the migration to an electronic format, particularly because electronic formats often use a different scale length than the 100 mm paper standard. METHODS: We performed a review of published studies investigating the measurement comparability of paper and electronic formats of the VAS. RESULTS: Our literature search yielded 26 studies published between 1997 and 2018 that reported comparison of paper and electronic formats using the VAS. After excluding 2 publications, 23 of the remaining 24 studies included in this review reported electronic formats of the VAS (eVAS) and paper formats (pVAS) to be equivalent. A further study concluded that eVAS and pVAS were both acceptable but should not be interchanged. eVAS length varied from 21 to 200 mm, indicating that 100 mm length is not a requirement. CONCLUSIONS: The literature supports the hypothesis that eVAS and pVAS provide comparable results regardless of the VAS length. When implementing a VAS on a screen-based electronic mode, we recommend following industry best practices for faithful migration to minimise the likelihood of non-comparability with pVAS.


Assuntos
Papel , Qualidade de Vida , Eletrônica , Humanos , Medição da Dor/métodos , Escala Visual Analógica
16.
Sci Rep ; 12(1): 2311, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-35145121

RESUMO

Many studies have been conducted on measuring avian influenza viruses and their hemagglutinin (HA) antigens via electrochemical principles; most of these studies have used gold electrodes on ceramic, glass, or silicon substrates, and/or labeling for signal enhancement. Herein, we present a paper-based immunosensor for label-free measurement of multiple avian influenza virus (H5N1, H7N9, and H9N2) antigens using flexible screen-printed carbon nanotube-polydimethylsiloxane electrodes. These flexible electrodes on a paper substrate can complement the physical weakness of the paper-based sensors when wetted, without affecting flexibility. The relative standard deviation of the peak currents was 1.88% when the electrodes were repeatedly bent and unfolded twenty times with deionized water provided each cycle, showing the stability of the electrodes. For the detection of HA antigens, approximately 10-µl samples (concentration: 100 pg/ml-100 ng/ml) were needed to form the antigen-antibody complexes during 20-30 min incubation, and the immune responses were measured via differential pulse voltammetry. The limits of detections were 55.7 pg/ml (0.95 pM) for H5N1 HA, 99.6 pg/ml (1.69 pM) for H7N9 HA, and 54.0 pg/ml (0.72 pM) for H9N2 HA antigens in phosphate buffered saline, and the sensors showed good selectivity and reproducibility. Such paper-based sensors are economical, flexible, robust, and easy-to-manufacture, with the ability to detect several avian influenza viruses.


Assuntos
Antígenos Virais/análise , Técnicas Biossensoriais/métodos , Dimetilpolisiloxanos , Técnicas Eletroquímicas/métodos , Eletrodos , Imunoensaio/métodos , Virus da Influenza A Subtipo H5N1/imunologia , Subtipo H7N9 do Vírus da Influenza A/imunologia , Vírus da Influenza A Subtipo H9N2/imunologia , Nanotubos de Carbono , Papel , Virologia/métodos , Animais , Aves , Humanos , Influenza Aviária/diagnóstico , Influenza Aviária/virologia , Influenza Humana/diagnóstico , Influenza Humana/virologia , Limite de Detecção , Reprodutibilidade dos Testes
17.
Chemosphere ; 295: 133892, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35134397

RESUMO

Due to the presence of various organic contaminants, improper disposal of pulp-paper wastewater poses harm to the environment and human health. In this work, pulp-paper sludge (PPS) after secondary treatment were collected from M/s Century Pulp-paper Mills in India, the chemical nature of the organic pollutants was determined after solvent extraction. All the isolates were able to produce lipase (6.34-3.93 U ml-1) which could account for the different fatty acids detected in the PPS. The dominant strains were in the classes of α and γ Proteobacteria followed by Firmicutes. The Shannon-Weiner diversity indexes for phylotype richness for the culturable and non-culturable bacterial community were 2.01 and 3.01, respectively, indicating the non-culturable bacterial strains has higher species richness and diversity compared to the culturable bacterial strains. However, the culturable strains had higher species evenness (0.94 vs 0.90). Results suggested only a few isolated strains were resistant to the POPs in the PPS, where as non-cultural bacteria survived by entering viable but non-cultural state. The isolated strains (Brevundimonas diminuta, Aeromonas punctata, Enterobacter hormaechei, Citrobacter braakii, Bacillus pumilus and Brevundimonas terrae) are known for their multidrug resistance but their tolerance to POPs have not previously been reported and deserved further investigation. The findings of this research established the presence of POPs which influence the microbial population. Tertiary treatment is recommended prior to the safe disposal of pulp paper mill waste into the environment.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Bactérias , Humanos , Resíduos Industriais/análise , Papel , Poluentes Orgânicos Persistentes , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos
18.
Carbohydr Polym ; 283: 119135, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35153011

RESUMO

To date, flexible pressure sensors built on silver nanowires (AgNWs) have attracted tremendous attention, owing to their versatile applications in wearable, human-interactive, health-monitoring devices. Cellulose and its derivatives, which show great promise in serving flexible pressure sensors as the desired substrate due to their natural abundance, biocompatibility, easy processibility, and low costs. Herein, we reported a rational strategy to design a silver nanowires-dual-cellulose conductive paper. Its morphology, chemical and crystal structures, thermal stability, mechanical performances, and electrical properties were carefully studied. The results suggested that good tensile properties (tensile strength ≤8.10 MPa), high electrical conductivity (≤ 1.74 × 104 S·m-1) with long-term stability, and good adhesion stability (bending cycles over 500) were obtained. Furthermore, the use of such conductive paper as substrate for versatile flexible pressure sensors was demonstrated, which exhibited fast response (~ 0.48 s) and high sensitivity, in response to finger motion, voice recognition, and human pulse, etc.


Assuntos
Celulose/química , Nanofios/química , Papel , Prata/química , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica , Humanos , Movimento (Física) , Pulso Arterial , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Resistência à Tração , Difração de Raios X/métodos
19.
Anal Chim Acta ; 1197: 339540, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35168717

RESUMO

Integration and storage of bioactive reagents is an important and challenging task in microfluidic paper-based analytical devices (µPADs). Here, we developed a convenient and universal method to store proteins and preserve their activities in µPADs by using aqueous two-phase systems (ATPs) evolved film. A polyethylene glycol (PEG)-dextran (DEX) double-layer film was formed through dehydration of ATPs. Functional biomolecules were stored in the bottom DEX layer on the basis of the biased partitioning and rehydrated conveniently by simple addition of buffer solution at usage. As a demonstration, enzyme immunoassay (EIA) of carcinoembryonic antigen was performed successfully on µPAD integrated with antibodies. Even after 104 days of storage at 4 °C and ambient conditions, the EIA signal just lost less than 10% and 30%, which meet the storage requirements of invitro diagnosis reagents. The ATPs evolved double-layer film has double functions of stabilization and insulation, and provide a high efficiency of biomolecule preservation, thereby promoting the applications of µPADs in POC diagnostic assay.


Assuntos
Proteínas , Água , Sistemas de Liberação de Medicamentos , Dispositivos Lab-On-A-Chip , Papel , Polietilenoglicóis
20.
Environ Monit Assess ; 194(3): 190, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-35165783

RESUMO

Early and on-site detection of environmental contaminations and physicochemical parameters of seawater is increasingly preferred to guarantee hazard minimization in many settings. In this paper, we describe a combination of microfluidic paper-based sensors (µPADs) and an Android-based smartphone application (App) for simultaneous on-site quantification of phosphate (PO4-P), silicate (SiO3-Si) and nitrite (NO2-N) in coastal seawater samples. The developed App can on-site capture, process, and quantify the µPAD colorimetric outputs. This App uses an image processing algorithm for quantifying color intensity and relating the RGB components to the analyte concentrations. The GPS-tagged data can be stored on the smartphone or sent via social networks. The significant factors affecting the detection of the analytes were optimized using Box-Behnken design. Under optimized parameters, the proposed method presented the linear ranges between 5 and 100 µg L-1 for phosphate (R2 = 0.9909), 5 to 100 µg L-1 (R2 = 0.9819) for nitrite and 10 to 600 µg L-1 (R2 = 0.9933) for silicate. The LODs of the method for detection of phosphate, nitrite and silicate were 1.52 µg L-1, 0.61 µg L-1 and 3.74 µg L-1, respectively. The device was successfully used to simultaneous analyze and map the PO4-P, SiO3-Si and NO2-N of Bushehr coastal seawater samples (Iran). The results were confirmed by the lab-based conventional colorimetric methods using spectrophotometer.


Assuntos
Colorimetria , Nitritos , Monitoramento Ambiental , Microfluídica , Nitritos/análise , Papel , Fosfatos , Silicatos , Smartphone
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