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Owing to its critical role in the development of female reproductive tissues and as a clinical biomarker, there is an urgent need to develop a rapid and cost-effective method to sensitively detect 17β-estradiol (E2). In this work, a folding aptasensor platform with microfluidic channels for the label-free electrochemical detection of E2 is described. The platform, designed with a delicate folding structure, integrating filter holes, microfluidic channels, reaction chambers, and a three-electrode system, is extremely easy to use. To increase the detection sensitivity and immobilize the aptamer, we synthesized a novel nanoassembly consisting of amine-functionalized single-walled carbon nanotube/new methylene blue/gold nanoparticles (AuNPs) and modified the working electrode with this nanoassembly. The calibration curve obtained from the experimental results exhibited a linear range between 10 pg mL-1 and 500 ng mL-1 (R2 = 0.993), and a detection limit of 5 pg mL-1 was achieved (S/N = 3). Furthermore, experiments to detect E2 in clinical serum were conducted, and the results were highly similar to those obtained using a large electrochemical luminescence apparatus. By integrating multiple functional components, adopting novel nanoassemblies, and using a folding structure, this paper-based platform not only has great potential as a simple and convenient integrated device for point-of-care testing of E2, but also as a portable, low-cost, and highly sensitive aptasensor platform capable of detecting many diagnostic biomarkers with the appropriate aptamers.

Norovirus is one of the leading causes of gastroenteritis, acute vomiting, intense diarrhoea, acute pain in the stomach, high fever, headaches, and body pain. Conventional methods of detection gave us very promising results but had disadvantages such as low sensitivity, cost ineffectiveness, reduced specificity and selectivity, etc. Therefore, biosensors can be a viable alternative device which can overcome all setbacks associated with the conventional method. An electrochemical sensor based on oxidized graphitic carbon nitride (Ox-g-C3N4) modified electrochemical paper-based analytical device (ePAD) was fabricated for the detection of norovirus DNA. The synthesized Ox-g-C3N4 nanosheets were characterized by field emission scanning electron microscopy (FESEM), X-ray Diffraction (XRD), UV-Vis spectroscopy and X-Ray Photoelectron Spectroscopy. The capture probe DNA (PDNA) modified electrodes were characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). These two characterization techniques were also employed to find the optimal scan rate, response time and temperature of the fabricated sensor. The fabricated biosensor showed a limit of detection (LOD) of 100 fM. Furthermore, the specificity of the reported biosensor was affirmed by testing the response of capture probe DNA with oxidized graphitic carbon nitride (PDNA/Ox-g-C3N4) modified ePAD on the introduction of a non-complimentary DNA. The fabricated ePAD sensor is easy to fabricate, cost effective and specific, and requires a minimum analysis time of 5 s.

We present results of the studies relating to fabrication of a microfluidic biosensor chip based on urchin like Ag@ Pd shell nano-hybrids that is capable of sensing alprazolam through electrochemical detection. Using this chip we demonstrate, with high reliability and in a time efficient manner, the detection of alprazolam present in buffer solutions at clinically relevant concentrations. Methylene blue (MB) was also doped as redox transition substance for sensing alprazolam. Nano-hybrids modified EμPAD showed wide linear range 1-300ng/ml and low detection limit of 0.025ng/l. Low detection limit can further enhance its suitability for forensic application. Nano-hybrids modified EμPAD was also employed for determination of drug in real samples such as human urine. Reported facile lab paper approach integrated with urchin like Ag@ Pd shell nano-hybrids could be well applied for the determination of serum metabolites.

Enteromorpha prolifera-derived Fe

Based on alkaline paper-making wastewater, a polymer catalyst (FQ) was prepared and characterized by FTIR, ESR and element analysis techniques. The results show that the catalyst has conjugated structure and the conjugate degree increases after heat treatment. The catalyst has quite high photo-catalytic activity, which was verified by the fact that the simulated dyeing wastewater containing methylene blue (MB) or acridine orange (AO) can be degraded completely in 20 minutes under natural light using FQ as the photo-catalyst. Therefore, the synthetic dyeing wastewater can be disposed of using the materials coming from paper-making wastewater. It is a very promising method to treat one kind of wastewater with the materials from another kind of wastewater.

Porous materials consisting of activated carbon and amorphous CaO-Al(2)O(3)-SiO(2) (CAS) compound were prepared from refuse paper and plastic fuel (RPF), (a mixture of old paper and plastic) by carbonizing and/or activating treatments. Samples formed by chemical activation using K(2)CO(3) showed a high specific surface area (S(BET)) of 1330 m(2)/g but a lower ash content due to being washed after activation. By contrast, samples prepared by physical activation using steam showed rather lower S(BET) (510 m(2)/g) due to higher ash contents. The physically activated samples showed much higher uptake properties for Ni(2+) (a representative heavy metal) and phosphate ions (a representative of a harmful oxyanion) than the chemically activated samples because of the higher content of amorphous CAS in the former samples. By contrast, the chemically activated samples showed higher uptake for methylene blue (MB, a representative organic material) than the physically activated samples because of the higher activated carbon content of higher surface area. Although differences in the sorption properties for Ni(2+), phosphate ion and MB were found between the physically and chemically activated samples, both samples show excellent multiple sorption properties for cation-anion combinations and inorganic-organic sorbents.

In the past few years, optical magnification endoscopy and chromoscopy have gained renewed interest in the West as a means for the early detection of minute lesions in patients with Barrett's oesophagus and in patients referred for colonic cancer screening. In Barrett's oesophagus, the vast majority of data on the use of chromoscopy deals with the application of methylene blue. Conventional videoendoscopy in combination with methylene blue staining improves the detection of Barrett's mucosa. A correlation has been shown between variation and intensity of staining and histologically verified stages of dysplasia or cancer. Magnification endoscopy and chromoscopy improve the detection of colonic non-polypoid lesions associated with neoplasia and carcinoma. Pitt pattern analysis enables the distinction of non-neoplastic non-polypoid lesions (type I and II) from neoplastic type non-polypoid lesions (type III-V) with great accuracy. It is certain that "old fashioned" chromoscopy combined with advanced endoscopic technology carry a great diagnostic potential and should be further put to the test for use in daily clinical practice.

For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst (PMS-Fe-380) was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer-Emmet-Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue (MB). The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover, leaching tests indicated that the leached iron is negligible (

Here we report on a new approach for the electrochemical detection of hydrogen peroxide (H 2 O 2 ) based on the co-immobilization of horseradish peroxidase and methylene blue on the functionalized carbon buckypaper supported by a titanium substrate. Cyclic voltammetry was used to study and optimize the performance of the resulting electrochemical biosensor. The proposed biosensor exhibited high analytical performance towards the quantification of H 2 O 2 at the physiological pH 7.4. Under optimized conditions, the biosensor shows a wide linear response range from 0.1 × 10 −6 to 5 × 10 −4 M concentrations of H 2 O 2 . The detection limit was determined to be 7.5 × 10 −8 M (based on S/N = 3). Reproducibility and stability of the fabricated biosensor were examined with satisfactory results. The biological relevance of the developed electrochemical biosensor has been further studied by the determination of H 2 O 2 in human urine samples of normal volunteers prior to and following the ingestion of coffee. Increased levels of urinary H 2 O 2 concentration suggest that oxidative stress is induced by coffee drinking in humans. There is considerable interest in oxidative stress as relates to human physiology. The sensitive determination of H 2 O 2 in human urine may serve as a valuable biomarker to effectively elucidate specific levels of oxidative stress in vivo.

Background: The fact that mucopolysaccharidoses (MPSes) are now treatable, and that the earlier treatment is initiated the better, is an indication for neonatal screening. The most efficient approach seems likely to be a multi‐tier procedure in which screening for urinary glycosaminoglycan (GAG) is followed by enzyme determinations in heelprick blood of newborns screening positive. Hitherto the method of choice for the determination of GAG has been the measurement of absorbance by a complex of GAG and 1,9‐dimethylmethylene blue (DMB). Method: We evaluated a DMB method in which absorbance by DMB is measured following its addition to the eluate obtained from paper‐borne newborn urine samples and is normalized relative to urinary creatinine. Calibration is performed with chondroitin‐6‐sulfate (Ch‐6‐S). Results: The limits of detection and quantification of GAG were 1.98 and 5.94 mg/dl, respectively. The within‐run coefficients of variation (CVs) of the GAG/creatinine ratio for 25, 31, and 70 mg/dl solutions of Ch‐6‐S in urine were 21.8, 16.4, and 10.5%, respectively, and the corresponding between‐run CVs were 25.0, 13.5, and 10.1%. Recovery from the urine spiked with 31 mg Ch‐6‐S/dl was 94.8%. Accuracy was also acceptable for all other GAGs except hyaluronic acid. For neonatal screening, the diagnostic threshold was tentatively established as 800 mg GAG/g creatinine, the 95th centile of samples from 903 infants aged 3–28 days, but the value of the GAG/creatinine ratio was negatively correlated with age. Application of the new method to samples from older individuals with and without MPS achieved 100% sensitivity and specificity when used with an age‐dependent threshold taken from the literature on the original DMB method. Conclusion: If used in the first tier of a multi‐tier screening protocol, the proposed method would allow the detection of abnormal levels of all GAGs except hyaluronic acid. J. Clin. Lab. Anal. 24:149–153, 2010. © 2010 Wiley‐Liss, Inc.

Objective This study analyzed two methods of measuring the absorbing capacity of paper points (PP), testing the hypothesis that there is a positive correlation between the results from the percentage of increase mass (PIM) and the linear dye penetration (LDP) methods. Methods The initial dry weight (IDW) of each PP was recorded using a digital balance before 1-mm introduction into one of the dye solutions, 1% methylene blue (MB) or 1% rodamine B (RB), for 10 s. The PP's were removed from the solution and weighed (final weight – FW). PIM was calculated from the difference between FW and IDW ( n = 50). The LDP was measured using a stereomicroscope and a ruler ( n = 50). Data was statistically analyzed using the Pearson correlation and Student's t tests. Results Moderate positive correlations between LDP and PIM methods were found using methylene blue ( r = 0.6356) and rodamine B ( r = 0.7743), partially confirming the study hypothesis, and suggesting that results from these two methods should be confronted carefully. Significance The results of this study suggest that the most reliable method of measuring the absorbing capacity of paper points is the PIM and investigators should be aware of differences between the two research protocols when comparing results from these two methods (PIM and LDP).

Three materials were prepared from paper sludge (PS) using different treatment processes and their sorption abilities for phosphate and methylene blue (MB) were determined. The samples were a powder sample prepared by heating PS in air (sample C), a pellet prepared by grinding, forming and heating PS in air (sample G) and a powder prepared by physical activation of PS in flowing wet nitrogen (sample A). The three samples were heated at 600-900 degrees C for 6h. On heating at 700-800 degrees C, the organic fibers, limestone (CaCO3), kaolinite (Al2Si2O5(OH)4) and talc (Mg3Si4O10(OH)2) in the original PS were converted to amorphous CaO-Al2O3-SiO2 (CAS) and talc in sample C, while CAS was formed in sample G and activated carbon, CAS and talc was formed in sample A. On heating at 900 degrees C the CAS converted to gehlenite (Ca2Al2SiO7) and anorthite (CaAl2Si2O8). The specific surface areas (SBET) of the three samples achieved maximum values of 23, 37 and 70 m2/g upon heating at 700, 600 and 600 degrees C, respectively. The SBET value of the activated sample A was distinctly lower than usually reported for activated carbon. The samples C, G and A achieved maximum phosphate sorption capacities of 2.04, 1.38 and 1.70 mmol/g, calculated from the Langmuir model, upon heating at 700, 700 and 800 degrees C, respectively. The maximum sorption capacity for phosphate in sample C is attributed to the sorption by CAS, namely, adsorption on the alumina component and precipitation as Ca-phosphates. The MB multifunctional sorption capacity of sample A was 0.11 mmol/g. The phosphate and MB sorption rates show better correlation with a pseudo-second order model than with other models.

The information available on ultrasound field distributions in cleaning baths is limited. Two techniques capable of providing this information have been investigated. The first employs a thermistor probe coated with ultrasound absorbing material and uses the rate of temperature rise when the ultrasound is switched on as a measure of local energy density. A motorized scanning frame has been used to map field distributions in three dimensions using the technique. The second technique, the Sarvazyan (dye/paper) method, uses Astralux paper placed in a bath containing an aqueous solution of methylene blue dye. More dye is transferred to the paper in areas where the ultrasound field is most intense. Pockets of gas are trapped in pores in the paper which provide additional nuclei for initiation of cavitation events and these produce small areas of intense staining about 1 mm in diameter, which are related to cavitational activity. The techniques reveal non-uniformities both in the field distribution and in the pattern of cavitational activity in ultrasound cleaning baths. Methods for assessing ultrasound field distributions are required in order to ensure that energy densities are sufficient to initiate cleaning action throughout ultrasonic cleaning baths.

The direct 1,9-dimethylmethylene blue (DMB) method for quantifying sulfated glycosaminoglycan (GAG) in urine (Clin Chem 1989; 35:374-9) has been adapted to a convenient means for sample collection and transport as a test to identify individuals with mucopolysaccharidosis (MPS) storage diseases. Results correlated moderately well (r = 0.85) with those of a commonly used, but more laborious, quantitative method. In studying factors to maximize differentiation of pathological from normal values, we found that GAG excretion (expressed as milligrams GAG per gram creatinine) fits a logarithmic function with respect to age and varies markedly below age five years. This must be considered in developing normative values and forming diagnoses. Of 112 separate urine specimens obtained from 41 MPS patients representing the major MPS diseases, glycosaminoglycan excretion by all exceeded that for age-matched normal individuals. The convenience of this method allowed us to establish the first normative values for three-week-old infants (n = 435) found to have a mean glycosaminoglycan excretion of 179 (SD 86.3) mg of GAG per gram of creatinine. This method improves the diagnostic capability for those MPS diseases that have been particularly difficult to identify (Sanfilippo's syndrome and Morquio's syndrome), and may also provide a test for other disorders with previously unrecognized abnormal excretion of glycosaminoglycan (e.g., mucolipidosis and acromesomelic dysplasia). Most importantly, this MPS diagnostic test is unique in its suitability for mass screening of newborn infants.

Paper electrophoretic fractionation in barbiturate (barbital) buffer, pH 9, of iodine-substituted insulin 0–10.8 I/mole showed that substitution with 4–6 I/mole influences the binding of zinc to a demonstrable extent. The effect appears to be due to substitution in the imidazole groups of the histidine residues. Substitution with iodine in the tyrosine residues seems to be without significance, at least at the lower degrees of iodination. The importance of the histidine residues for the binding of zinc is shown by selective destruction of the imidazole groups by photo-oxidation, sensitized by methylene blue. Carbamylation of the N-terminal α-amino groups in the A- and B-chains with KOCN only slightly influences the ability to bind zinc while carbamylation with fluorescein isothiocyanate in the N-terminal of the B-chain brings about a more pronounced reduction in the zinc binding capacity.