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1.
Biosensors (Basel) ; 11(4)2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33917183

RESUMO

This review summarizes the state of the art of paper-based biosensors (PBBs) for coronavirus disease 2019 (COVID-19) detection. Three categories of PBB are currently being been used for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics, namely for viral gene, viral antigen and antibody detection. The characteristics, the analytical performance, the advantages and drawbacks of each type of biosensor are highlighted and compared with traditional methods. It is hoped that this review will be useful for scientists for the development of novel PBB platforms with enhanced performance for helping to contain the COVID-19 outbreak, by allowing early diagnosis at the point of care (POC).


Assuntos
Técnicas Biossensoriais/métodos , Papel , Antígenos Virais/análise , Técnicas Biossensoriais/instrumentação , Sistemas CRISPR-Cas/genética , Humanos , Imunoensaio , Sistemas Automatizados de Assistência Junto ao Leito , RNA Viral/análise , /isolamento & purificação , /metabolismo
2.
BMC Anesthesiol ; 21(1): 115, 2021 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-33853526

RESUMO

BACKGROUND: The current coronavirus infectious disease 2019 (COVID-19) pandemic has caused unexpected pressure on medical supplies, interrupting supply chains and increasing prices. The supply of antiviral filters which form an essential part of the ventilator circuit have been affected by these issues. Three-dimensional (3D) printing may provide a solution to some of these issues. METHODS: We designed and tested 3D printed heat and moisture exchange (HME) and antiviral casing. For each casing we tested two different filter materials derived from a sediment water filter cartridge or 1.5-µm glass fiber filter paper. A polyurethane sponge was used for the HME. Each design was tested for circuit leak, circuit compliance, peak inspiratory pressure and casing integrity using methylene blue dye. RESULTS: We designed, produced, and tested two different types of antiviral filters with six different internal configurations. Overall, we tested 10 modified filter designs and compared them with the original commercial filter. Except for the combination of 1.5-µm filter paper and 5 mm sponge peak inspiratory pressure and circuit compliance of the filters produced were within the operating limits of the ventilator. All In addition, all filters passed the dye test. CONCLUSIONS: Our filter may be of particular importance to those working in low middle-income countries unable to compete with stronger economies. Our design relies on products available outside the healthcare supply chain, much of which can be purchased in grocery stores, hardware stores, or industrial and academic institutions. We hope that these HMEs and viral filters may be beneficial to clinicians who face critical supply chain issues during the COVID-19 pandemic.


Assuntos
Impressão Tridimensional , Ultrafiltração/instrumentação , Ventiladores Mecânicos , Vírus , /terapia , Corantes , Desenho de Equipamento , Estudos de Viabilidade , Humanos , Pandemias , Papel , Pico do Fluxo Expiratório , Poliuretanos , Reprodutibilidade dos Testes , Tampões de Gaze Cirúrgicos
3.
Environ Sci Pollut Res Int ; 28(14): 18284-18293, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33665692

RESUMO

The objective of this study was to check the potential of crude xylano-pectinolytic enzymes in bleaching of rice straw pulp, in order to reduce the toxic waste load for managing the environmental pollution. The xylano-pectinolytic enzymatic bleaching step for delignification was found to be most effective at pulp consistency 1:10 g/ml, xylanase:pectinase dose of 9:4 IU/ml, pH 8.5 and treatment time 180 min at temperature of 55 °C, and resulted in lowering of kappa number of the rice straw pulp by 15.29%. In subsequent bleaching stages, this enzymatic pre-bleaching treatment also resulted in 30% reduction of active chlorine dioxide dose without any loss of optical properties. Significant improvement in various physical properties of the enzymes treated pulp, tear index (15.43%), breaking length (11.11%), double fold number (25.92%), burst index (9.88%) and viscosity (13.63%), and Gurley porosity (39.86%) was also noticed. This approach resulted in reduction of BOD and COD values by 21.07% and 26.57%, respectively. This is the first study on the use of crude xylano-pectinolytic enzymes for bio-bleaching of rice straw pulp.


Assuntos
Oryza , Papel , Poligalacturonase , Compostos de Sódio , Temperatura
4.
Talanta ; 225: 121978, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33592726

RESUMO

In modern times, viruses still threaten people's lives. Among them, norovirus was the main pathogenic factor in the cause of gastroenteritis and foodborne illness, of which the GII.4 and GII.17 genotypes are prevalent in China and most parts of the world. A simple and low-cost platform for rapid and accurate norovirus detection remains a major challenge. After the cell-free system and paper-based chromogenic system were optimized, a rapid and specific norovirus detection method was established based on norovirus-specific sequences in combination with toehold switch elements. The development of a visible color change during detection eliminates the need for any complicated instruments. We validated this strategy and its specificity in differentiating GII.4, GII.17, Zika virus, and human coronavirus HKU1. The results showed that the optimized detection system not only provided a simple and rapid detection method for the sufficient differentiation of the two norovirus genotypes but also showed high specificity and no cross-reactivity with other viruses. Using nucleic acid isothermal amplification, this assay showed a limit of detection of 0.5 pM for the GII.4 genotype and 2.6 fM for the GII.17 genotype in reactions that could be observed directly with the naked eye. Our results suggested that this paper-based colorimetric method could serve as a simple and low-cost visual detection method for pathogens in clinical samples, especially in remote or rural areas.


Assuntos
Infecções por Caliciviridae/diagnóstico , Colorimetria/métodos , Gastroenterite/diagnóstico , Infecções por Caliciviridae/virologia , Colorimetria/economia , Colorimetria/instrumentação , Análise Custo-Benefício , Gastroenterite/virologia , Genótipo , Humanos , Norovirus/genética , Norovirus/fisiologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Papel , RNA Viral/genética , Sensibilidade e Especificidade
5.
ACS Appl Mater Interfaces ; 13(7): 8071-8081, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33587589

RESUMO

Biomarkers in sweat are a largely untapped source of health information. Most of the currently available sweat harvesting and testing devices are incapable of operating under low-sweat rates such as those experienced by humans at rest. Here we analyze the in vitro and in vivo sampling of sweat through osmosis via the use of a hydrogel interfaced with the skin, without need for active perspiration. The hydrogel also interfaces with paper-based microfluidics to transport the fluid via capillary forces toward a testing zone and then evaporation pad. We show that the hydrogel solute content and area of the evaporation pad regulate the long-term extraction of sweat and its associated biomarkers. The results indicate that the platform can sample biomarkers from a model skin system continuously for approximately 12 h. On-skin testing of the platform on both resting and exercising human subjects confirms that it can sample sweat lactate directly from the surface of skin. The results highlight that lactate in sweat increases with exercise and as a direct result of muscle activity. Implementation of such new principles for sweat fluid harvesting and management via wearable patch devices can contribute toward the advancement of next generation wearables.


Assuntos
Técnicas Biossensoriais , Técnicas Analíticas Microfluídicas , Pressão Osmótica , Pele/química , Suor/química , Dispositivos Eletrônicos Vestíveis , Biomarcadores/análise , Humanos , Hidrogéis/química , Papel
6.
Biotechnol J ; 16(2): e2000126, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33460221

RESUMO

Paper is increasingly recognized as a portable substrate for cell culture, due to its low-cost, flexible, and special porous property, which provides a native cellular 3D microenvironment. Therefore, paper-based microfluidics has been developed for cell culture and biomedical analysis. However, the inability of continuous medium supply limits the wide application of paper devices for cell culture. Herein, a paper-based microfluidic device is developed with novel folded paper strips as wick-like structure, which is used for medium self-driven perfusion. The paper with patterns of hydrophilic channel, culture areas, and hydrophobic barrier could be easily fabricated through wax-printing. After printing, the hydrophilic paper strip at the periphery of the lower layer is then folded at 90° and extended into the medium container for continuous automatic supply of medium to the cell culture area. Tumor cells cultured in the paper device are tested for anti-cancer drug screening. Visualized cell viability and chemical sensitivity testing can be achieved by colorimetry combined with simple smartphone imaging, effectively reducing precision instrument dependence. The wick paper-based microfluidic device for cell culture endows the method the advantages of lower cost, ease-of-operation, miniaturization, and shows a great potential for large-scale cell culture, antibody drug production, and efficient screening.


Assuntos
Técnicas Analíticas Microfluídicas , Antineoplásicos/farmacologia , Técnicas de Cultura de Células , Colorimetria , Dispositivos Lab-On-A-Chip , Microfluídica , Papel
7.
Pediatr Emerg Care ; 37(2): 126-130, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33512892

RESUMO

OBJECTIVE: We hypothesized that a paper documentation and discharge bundle can expedite patient care during an influenza-related surge. METHODS: Retrospective cohort study of low-acuity patients younger than 21 years surging into a pediatric emergency department between January and March 2018 with influenza-like illness. Patient visits documented using a paper bundle were compared with those documented in the electronic medical record on the same date of visit. The primary outcome of interest was time from physician evaluation to discharge for patient visits documented using the paper bundle compared with those documented in the electronic medical record. Secondary outcome was difference in return visits within 72 hours. We identified patient and visit level factors associated with emergency department length of stay. RESULTS: A total of 1591 patient visits were included, 1187 documented in the electronic health record and 404 documented using the paper bundle. Patient visits documented using the paper bundle had a 21% shortened median time from physician evaluation to discharge (41 minutes; interquartile range, 27-62.8 minutes) as compared with patient visits documented in the electronic health record (52 minutes; interquartile range, 35-61 minutes; P < 0.001). There was no difference in return visits (odds ratio, 0.7; 95% confidence interval, 0.2, 2.2). CONCLUSIONS: Implementation of paper charting during an influenza-related surge was associated with shorter physician to discharge times when compared with patient visits documented in the electronic health record. A paper bundle may improve patient throughput and decrease emergency department overcrowding during influenza or coronavirus disease-related surge.


Assuntos
Documentação/métodos , Serviço Hospitalar de Emergência/estatística & dados numéricos , Influenza Humana/terapia , Registros Médicos/estatística & dados numéricos , Alta do Paciente/estatística & dados numéricos , Criança , Pré-Escolar , Registros Eletrônicos de Saúde/estatística & dados numéricos , Feminino , Humanos , Lactente , Recém-Nascido , Tempo de Internação/estatística & dados numéricos , Masculino , Papel , Readmissão do Paciente/estatística & dados numéricos , Estudos Retrospectivos
8.
Food Chem ; 346: 128901, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33450645

RESUMO

An electrochemical deposition method was used to fabricate a gold nanoflower (AuNF) and carbon nanoparticle (CNP) modified carbon paper (CP) sensor (AuNFs-CNPs/CP) for the low-cost detection of 5-methyltetrahydrofolate (5-mTHF) in egg yolk. AuNF morphology and structures were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), revealing nanoflower sizes in the 50 to 200 nm range. AuNFs formed on the sensor were in the Au0. We evaluated 5-mTHF assay performance using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The AuNFs-CNPs/CP sensor detected 5-mTHF concentrations in the ranges from 1 to 5 mg L-1 and 1-20 µg L-1, with an excellent limit of detection of 1 µg L-1 and good selectivity toward 5-mTHF, when compared to other potentially interfering molecules in samples. The AuNFs-CNPs/CP sensor was also used to detect 5-mTHF in folate-rich, and was found to be twice than that of ordinary egg yolk.


Assuntos
Gema de Ovo/química , Técnicas Eletroquímicas/métodos , Papel , Tetra-Hidrofolatos/análise , Carbono/química , Gema de Ovo/metabolismo , Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Limite de Detecção , Nanoestruturas/química , Reprodutibilidade dos Testes
9.
J Mater Chem B ; 9(4): 983-991, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33393541

RESUMO

The major obstacle to developing nanozymes which are considered as promising alternatives to natural enzymes is their moderate performance, including poor affinity for substrates, low catalytic activity, and severe pH-dependence. To address these issues, herein, we synthesize ultrathin layered double hydroxide (LDH) nanosheets with a thickness of 1.4 nm and an average lateral size of 23 nm using a fast-precipitation method. Through the rational design of their compositions, it is found that NiMn LDHs exhibit the optimum peroxidase mimicking performance with excellent substrate affinity, high catalytic activity (a limit of detection (LOD) of 0.04 µM H2O2) and robustness in a wide pH range (from 2.6 to 9.0), which is superior to that of natural horseradish peroxidase (HRP). The main active centers are identified as Mn sites because of their strong Lewis acidity and low redox potential. Furthermore, a series of disposable paper bioassays based on NiMn LDH nanozymes are designed and used for the highly sensitive detection of H2O2 and ascorbic acid (AA).


Assuntos
Peroxidase do Rábano Silvestre/química , Hidróxidos/química , Manganês/química , Nanopartículas/química , Níquel/química , Papel , Ácido Ascórbico/análise , Bioensaio , Técnicas Biossensoriais , Peroxidase do Rábano Silvestre/metabolismo , Peróxido de Hidrogênio/análise , Hidróxidos/metabolismo , Manganês/metabolismo , Níquel/metabolismo , Tamanho da Partícula , Propriedades de Superfície
10.
ACS Appl Mater Interfaces ; 13(3): 3576-3590, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33449630

RESUMO

The plasmonic properties of gold nanoparticles (AuNPs) are a promising tool to develop sensing alternatives to traditional, enzyme-catalyzed reactions. The need for sensing alternatives, especially in underdeveloped areas of the world, has given rise to the application of nonenzymatic sensing approaches paired with cellulosic substrates to biochemical analysis. Herein, we present three individual, low-step, wet-chemistry, colorimetric assays for three target biomarkers, namely, glucose, uric acid, and free cholesterol, relevant in diabetes control and their translation into paper-based assays and microfluidic platforms for multiplexed analysis. For glucose determination, an in situ AuNPs synthesis approach was applied into the developed µPAD, giving semiquantitative measures in the physiologically relevant range. For uric acid and cholesterol determination, modified AuNPs were used to functionalize paper with a gold-on-paper approach with the optical properties changing based on different aggregation degrees and hydrophobic properties of particles dependent on analyte concentration. These paper-based assays show sensitivity ranges and limits of detection compatible for target analyte level determination and detection limits comparable to those of similar enzymatic, colorimetric systems, relying only on plasmonic transduction without the need for enzymatic activity or other chromogenic substrates. The resulting paper-based assays were integrated into a single 3D, multiplex paper-based device using paper microfluidics, showing the capability for performing different colorimetric assays with distinct requirements in terms of sample flow and sample uptake in test zones using a combination of both horizontal and vertical flows inside the same device. The presented device allows for multiparametric, colorimetric measures of different metabolite levels from a single complex sample matrix drop using digital color analysis, showing the potential for development of low-cost, low-complexity tools for diagnostics toward the point-of-care.


Assuntos
Colorimetria/instrumentação , Ouro/química , Dispositivos Lab-On-A-Chip , Nanopartículas Metálicas/química , Papel , Animais , Biomarcadores/sangue , Glicemia/análise , Colesterol/sangue , Desenho de Equipamento , Cabras , Humanos , Sistemas Automatizados de Assistência Junto ao Leito , Ácido Úrico/análise
11.
ACS Appl Mater Interfaces ; 13(4): 5486-5497, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33491443

RESUMO

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly-m-phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.


Assuntos
Nanotubos de Carbono/química , Papel , Fenilenodiaminas/química , Ácidos Ftálicos/química , Polímeros/química , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/instrumentação , Condutividade Elétrica , Humanos , Monitorização Fisiológica/instrumentação , Movimento (Física) , Nanotubos de Carbono/ultraestrutura
12.
Ecotoxicol Environ Saf ; 210: 111874, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33421723

RESUMO

Given the high content of Ca2+ in waste paper recycling wastewater, the anaerobic granular sludge (AnGS) undergoes calcification during wastewater treatment and affects the treatment efficiency. To restore the activity of calcified AnGS and improve the performance of AnGS, four types of N-acyl-homoserine lactones (AHLs) were added to the AnGS system while papermaking wastewater treatment. The addition of N-butyryl-DL-homoserine lactone(C4-HSL) and N-octanoyl-DL-homoserine lactone (C8-HSL) had an inhibitory affect the COD removal efficiency and SMA of sludge at the inception. The addition of N-hexanoyl-L-homoserine lactone (C6-HSL) has no obvious effect on the COD removal efficiency, but can improve the SMA of sludge more obviously. The addition of N-(ß-ketocaproyl)-DL-homoserine lactone (3O-C6-HSL) can increased COD removal efficiency and promoted SMA together obviously. The addition of C6-HSL and 3O-C6-HSL can increase volatile suspended solid (VSS)/total suspended solid (TSS), and regulate extracellular polymeric substance (EPS) secretion in AnGS. Analysis of microbial sequencing revealed changes in the microbial community structure following AHL addition, which enhanced the methane metabolism pathway in sludge. The addition of C6-HSL, C8-HSL, and 3O-C6-HSL increased Methanosaeta population, thus increasing the aceticlastic pathway in sludge. Thus, exogenous AHLs can play an important role in regulating microbial community structure, and in improving the performance of AnGS.


Assuntos
Lactonas/administração & dosagem , Microbiota/efeitos dos fármacos , Esgotos , Anaerobiose , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Metano/metabolismo , Papel , Águas Residuárias
13.
Anal Chem ; 93(4): 1880-1888, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33430590

RESUMO

This Feature summarizes recent works in paper-based potentiometry and voltammetry in heavy metal determination. Interactions of paper substrates with heavy metals, influence on the sensing response, and modification methods applied to paper substrates to improve the performance of recently developed electrochemical sensors are discussed. Since the rekindling of interest in paper-based analytical devices, methodologies and electrode designs for heavy metal determinations are highlighted. Promising aspects of the use of these sensors for samples containing solids and the increased versatility of the use of paper in analytics offers the possibility of increased acceptance of these low-cost platforms.


Assuntos
Técnicas Eletroquímicas/métodos , Metais Pesados/química , Papel , Técnicas Eletroquímicas/economia , Técnicas Eletroquímicas/instrumentação , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos
14.
Biosens Bioelectron ; 177: 112672, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33461849

RESUMO

Accurate, rapid, and low-cost molecular diagnostics is essential in managing outbreaks of infectious diseases, such as the pandemic of coronavirus disease 2019 (COVID-19). Accordingly, microfluidic paper-based analytical devices (µPADs) have emerged as promising diagnostic tools. Among the extensive efforts to improve the performance and usability of diagnostic tools, biosensing mechanisms based on electrochemical impedance spectroscopy (EIS) have shown great promise because of their label-free operation and high sensitivity. However, the method to improve EIS biosensing on µPADs is less explored. Here, we present an experimental approach to enhancing the performance of paper-based EIS biosensors featuring zinc oxide nanowires (ZnO NWs) directly grown on working electrodes (WEs). Through a comparison of different EIS settings and an examination of ZnO-NW effects on EIS measurements, we show that ZnO-NW-enhanced WEs function reliably with Faradaic processes utilizing iron-based electron mediators. We calibrate paper-based EIS biosensors with different morphologies of ZnO NWs and achieve a low limit of detection (0.4 pg ml-1) in detecting p24 antigen as a marker for human immunodeficiency virus (HIV). Through microscopic imaging and electrochemical characterization, we reveal that the morphological and the electrochemical surface areas of ZnO-NW-enhanced WEs indicate the sensitivities and sensing ranges of the EIS nanobiosensors. Finally, we report that the EIS nanobiosensors are capable of differentiating the concentrations (blank, 10 ng ml-1, 100 ng ml-1, and 1 µg ml-1) of IgG antibody (CR3022) to SARS-CoV-2 in human serum samples, demonstrating the efficacy of these devices for COVID-19 diagnosis. This work provides a methodology for the rational design of high-performance EIS µPADs and has the potential to facilitate diagnosis in pandemics.


Assuntos
Técnicas Biossensoriais/instrumentação , /diagnóstico , Espectroscopia Dielétrica/instrumentação , /isolamento & purificação , Técnicas Biossensoriais/métodos , /métodos , Espectroscopia Dielétrica/métodos , Desenho de Equipamento , Humanos , Dispositivos Lab-On-A-Chip , Limite de Detecção , Nanofios/química , Papel , Óxido de Zinco/química
15.
Carbohydr Polym ; 254: 117406, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357893

RESUMO

Cellulosic nanomaterials are in the focus of academia and industry to realize light-weight biobased materials with remarkable strength. While the effect is well known, the distribution of these nanomaterials are less explored, particularly for paper sheets. Here, we explore the 3D distribution of micro and nanosized cellulosic particles in paper sheets and correlate their extent of fibrillation to the distribution inside the sheets and subsequently to paper properties. To overcome challenges with contrast between the particles and the matrix, we attached probes on the cellulose nano/microparticles, either by covalent attachment of fluorescent dyes or by physical deposition of cobalt ferrite nanoparticles. The increased contrast enabled visualization of the micro and nanosized particles inside the paper matrix using multiphoton microscopy, X-ray microtomography and SEM-EDX. The results indicate that fibrillary fines enrich at pores and fiber-fiber junctions, thereby increasing the relative bonded area between fibers to enhance paper strength while CNF seems to additionally form an inner 3D network.


Assuntos
Materiais Biocompatíveis/química , Celulose/química , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Nanofibras/química , Nanopartículas/química , Papel , Coloração e Rotulagem/métodos , Corantes Fluorescentes/química , Microscopia Eletrônica de Varredura , Porosidade , Espectrometria por Raios X , Resistência à Tração , Microtomografia por Raio-X
16.
ACS Appl Mater Interfaces ; 13(1): 1967-1978, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33372754

RESUMO

There is currently a growing demand for flexible strain sensors with high performance and water repellency for various applications such as human motion monitoring, sweat or humidity detection, and certain underwater tests. Among these strain sensors, paper-based ones have attracted increasing attention because they coincide with the future development trend of environment-friendly electronic products. However, paper-based electronics are easy to fail when they encounter water and are thus unable to be applied to humid or underwater circumstances. Herein, based on a strategy of coupling bionics inspired by lotus leaf and scorpion, which exhibit superhydrophobic characteristics and ultrasensitive vibration-sensing capacity, respectively, a paper-based strain sensor with high sensitivity and water repellency is successfully fabricated. As a result, the strain sensor exhibits a gauge factor of 263.34, a high strain resolution (0.098%), a fast response time (78 ms), excellent stability over 12,000 cycles, and a water contact angle of 164°. Owing to the bioinspired structures and function mechanisms, the paper-based strain sensor is suitable to not only serve as regular wearable electronics to monitor human motions in real-time but also to detect subtle underwater vibrations, demonstrating its great potential for numerous applications like wearable electronics, water environmental protection, and underwater robots.


Assuntos
Monitorização Fisiológica/instrumentação , Papel , Estresse Mecânico , Dispositivos Eletrônicos Vestíveis , Adulto , Animais , Biomimética/métodos , Técnicas Biossensoriais , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lotus , Masculino , Movimento , Folhas de Planta/química , Escorpiões , Vibração , Água/química
17.
Ann Work Expo Health ; 65(2): 206-218, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33313651

RESUMO

OBJECTIVES: Bisphenol A (BPA) is the most used colour developer in thermal paper for cashiers receipts, labels, and tickets. BPA can migrate onto the skin and be absorbed when handling these papers. BPA is a known endocrine disruptor and is therefore being replaced in thermal paper by some alternatives such as Bisphenol S (BPS), D-8, and Pergafast 201® (PF201). To our knowledge, no studies have characterized skin permeation of these BPA alternatives. METHODS: We measured/characterized skin absorption for BPA, BPS, D-8, and PF201 through ex vivo human skin using flow-through diffusion cells according to OECD guideline 428. Skin samples were 7-12 per test substance from three different skin donors. Skin metabolism was studied for BPA. Dermal absorption was expressed as the amount of the BPA alternatives in the receptor fluid over applied dose in percent (%). RESULTS: The absorbed dose after 24 h of exposure was 25% for BPA, 17% for D-8, 0.4% for BPS, and D-8 >> BPS > PF201. These results are in agreement with their log Kow and molecular weights. We provided here the necessary data to estimate the extent of skin absorption of BPA analogues, which is a necessary step in risk assessment, and ultimately evaluate public health risks posed by D-8, BPS, and PF201.


Assuntos
Exposição Ocupacional , Absorção Cutânea , Compostos Benzidrílicos , Humanos , Exposição Ocupacional/análise , Papel , Fenóis , Pele
18.
Carbohydr Polym ; 254: 117430, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357905

RESUMO

This study aims to understand the effect of micro- and nanofibrillated cellulose (MNFC) on the tensile index, softness, and water absorbency of tissue paper. MNFC was produced from four different fiber sources. The results show that MNFC acts as an effective strength enhancer at the expense of a reduced water absorbency and softness. The impact of the fiber source on MNFC manufacturing cost and the trade-off with performance was also investigated. MNFCs produced from southern bleached hardwood kraft, northern bleached softwood kraft, and deinked pulp exhibited similar performance trends with the MNFC from the deinked pulp having a significantly lower cost. This suggests that MNFCs with similar degrees of fibrillation may be used interchangeably regardless of the fiber source, revealing the possibility to minimize MNFC manufacturing costs based on fiber selection. MNFC produced from bleached Eucalyptus kraft showed the lowest degree of fibrillation and the lowest strength improvements among the MNFCs evaluated.


Assuntos
Celulose/química , Eucalyptus/química , Nanofibras/química , Papel , Madeira/química , Celulose/isolamento & purificação , Humanos , Hidrólise , Higiene , Teste de Materiais , Molhabilidade
19.
Int J Biol Macromol ; 168: 331-338, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-33310098

RESUMO

Nanofibrillated cellulose (NFC), a promising bio-based nanomaterial, has received much attention in the field of coating preparation due to its unique properties. Herein, NFC was prepared from microcrystalline cellulose (MCC) via high-pressure homogenization process and deliberately employed as coating agent to enhance the properties of paper coatings and coated paper. The results demonstrated that the obtained paper coatings exhibited strong NFC concentration dependence on rheological behavior and displayed decreased water retention value with the increased NFC addition. Meanwhile, NFC addition was found to lead to the reduced Cobb value, improved air resistance, and enhanced tensile strength of coated paper. Under an optimized NFC addition of 0.30-0.40%, the properties of coated paper generally reached the optimum state. Moreover, SEM observation further confirmed that NFC addition imparted a relatively uniform surface structure to coated paper. Hence, NFC could be defined as an effective coating agent for developing high-performance coated paper for food packaging applications.


Assuntos
Celulose/química , Embalagem de Alimentos/métodos , Nanofibras/química , Papel , Reologia , Temperatura , Resistência à Tração , Água/química
20.
Carbohydr Polym ; 251: 116975, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142552

RESUMO

Separator is a vital component of lithium-ion batteries (LIBs) due to its important roles in the safety and electrochemical performance of the batteries. Herein, we reported a cellulose nanofibrils (CNFs) reinforced pure cellulose paper (CCP) as a LIBs separator fabricated by a facile filtration process. The nanosized CNFs played crucial roles as a tuner to optimize the pore size of the as-prepared CCP, and also as a reinforcer to improve the mechanical strength of the resultant CCP. Results showed that the tensile strength of the CCP with 20 wt.% CNFs was 227 % higher compared to the commercial cellulose separator. In addition, the lithium cobalt oxide/lithium metal battery assembled with CCP separator displayed better cycle performance and working stability (capacity retention ratio of 91 % after 100 cycles) compared to the batteries with cellulose separator (52 %) and polypropylene separator (84 %) owing to the multiple synergies between CCP separator and electrolytes.


Assuntos
Celulose , Fontes de Energia Elétrica , Lítio , Celulose/química , Celulose/ultraestrutura , Eletroquímica , Eletrólitos , Lítio/química , Microscopia Eletrônica de Varredura , Nanofibras/química , Nanofibras/ultraestrutura , Papel , Porosidade , Resistência à Tração
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