scholarly journals A Miniature pH Probe Using Functional Microfiber Bragg Grating

Optics ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 202-212 ◽  
Author(s):  
Yang Ran ◽  
Peng Xiao ◽  
Yongkang Zhang ◽  
Deming Hu ◽  
Zhiyuan Xu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Ph Sensor ◽  
Fiber Surface ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Layer By Layer ◽  
Compact Size ◽  
Layer Technique ◽  
Order Of Magnitude ◽  
Ph Probes

Operando and precisely probing aqueous pH is fundamentally demanded, both in chemical and biological areas. Conventional pH probes, subjected to the larger size, are probably unfit for application in some extreme scenarios, such as a trace amount of samples. In this paper, we have further developed the pH sensor that leverages the microfiber Bragg grating with an ultra-compact size down to an order of magnitude of 10−14 m3. Using the electrostatic self-assembly layer-by-layer technique, the functional film consisting of sodium alginate, which harnesses a pH-dependent hygroscopicity, is immobilized on the fiber surface. Consequently, the alteration of aqueous pH could be quantitatively indicated by the wavelength shift of the grating resonance via the refractive index variation of the sensing film due to the water absorption or expulsion. The grating reflections involving fundamental mode and higher order mode exhibit the sensitivities of −72 pm/pH and −265 pm/pH, respectively. In addition, temperature compensation can be facilitated by the recording of the two reflections simultaneously. Furthermore, the modeling and simulation results predict the pivotal parameters of the configuration in sensitivity enhancement. The proposed proof-of-concept enriches the toolbox of pH sensor for catering to the need of detection in some extremely small spaces—for example, the living cells or the bio-tissues.

scholarly journals Production of antibacterial filter paper from wood cellulose

BioResources ◽  
2011 ◽  
Vol 6 (1) ◽  
pp. 891-900 ◽  
Author(s):  
Reza Imani ◽  
Mohammad Talaiepour ◽  
Joydeep Dutta ◽  
Mohammad R. Ghobadinezhad ◽  
Amir H. Hemmasi ◽  
...  
Keyword(s):  
Filter Paper ◽  
Food Packaging ◽  
Pathogenic Bacteria ◽  
Antibacterial Properties ◽  
Fiber Surface ◽  
Personal Hygiene ◽  
Layer By Layer ◽  
Wood Fibers ◽  
Minimum Requirement ◽  
Layer Technique

Paper has a visible market-share in hygiene products either in the form of personal hygiene or as food packaging. The designation “hygiene”, though it suggests cleanliness, does not imply antibacterial properties; rather it can be stated that hygiene products do not initiate microorganism growth. Antibacterial products could restrict propagation of pathogenic bacteria either by holding bacteria or by trapping and neutralizing them. Most research in this field has been conducted using textile fibers as a substrate, but the present work uses paper instead. The objective was to produce an antibacterial filter paper capable of trapping and neutralizing pathogenic microorganisms using wood fibers. To produce antibacterial paper, chitosan and nanosilver capped with PAA (polyacrylic acid) were deposited on the fiber surface using a layer-by-layer technique. Samples for the tests were prepared from refined bleached softwood (RBSW) kraft pulp. The deposition of antibacterial agents on fiber as well as paper were monitored using a zeta potential analyzer (ZPA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIRS). The minimum requirement for deposition of the agents was a multilayer comprised of eight alternating layers. The deposition onto fiber or paper had no effect on tensile strength or the pore structure of the substrate.

scholarly journals A Lamping U-Shaped Fiber Biosensor Detector for MicroRNA

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1509
Author(s):  
Hsin-Yi Wen ◽  
Chun-Wei Huang ◽  
Yu-Le Li ◽  
Jing-Luen Chen ◽  
Yao-Tsung Yeh ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Silicon Dioxide ◽  
Self Assembly ◽  
Transmission Loss ◽  
Limit Of Detection ◽  
Fiber Surface ◽  
Coefficient Of Determination ◽  
Wavelength Shift ◽  
Good Sensitivity ◽  
Microrna Detection

This study presents a U-shaped optical fiber developed for a facile application of microRNA detection. It is fabricated by the lamping process and packaged in a quartz tube to eliminate human negligence. In addition, silanization and electrostatic self-assembly are employed to bind gold nanoparticles and miRNA-133a probe onto the silicon dioxide of the fiber surface. For Mahlavu of hepatocellular carcinoma (HCC), detection is determined by the wavelength shift and transmission loss of a U-shaped optical fiber biosensor. The spectral sensitivity of wavelength and their coefficient of determination are found at −218.319 nm/ ng/mL and 0.839, respectively. Concurrently, the sensitivity of transmission loss and their coefficient of determination are found at 162.394 dB/ ng/mL and 0.984, respectively. A method for estimating the limit of detection of Mahlavu is at 0.0133 ng/mL. The results show that the proposed U-shaped biosensor is highly specific to miRNA-133a and possesses good sensitivity to variations in specimen concentration. As such, it could be of substantial value in microRNA detection.

scholarly journals pH-Responsive nanofiltration membranes based on porphyrin supramolecular self-assembly by layer-by-layer technique

RSC Advances ◽  
2017 ◽  
Vol 7 (75) ◽  
pp. 47397-47406 ◽  
Author(s):  
Chenglin Wu ◽  
Lizhi Zhao ◽  
Yuzhong Zhang
Keyword(s):  
Self Assembly ◽  
Layer By Layer ◽  
Nanofiltration Membrane ◽  
Ph Responsive ◽  
Nanofiltration Membranes ◽  
Layer Technique ◽  
Layer By Layer Technique

A novel pH-responsive nanofiltration membrane was fabricated by means of layer-by-layer technique based on porphyrin supramolecular self-assembly.

Biomimetic “Nacre-like” Films Prepared via Layer-by- Layer Self-assembly of Mica, Polyvinyl Alcohol and Polymethyl Methacrylate

2021 ◽  
Author(s):  
Yining Gao ◽  
Peng Liu ◽  
Chuanlin Hu ◽  
Lu Yang
Keyword(s):  
Polyvinyl Alcohol ◽  
Polymethyl Methacrylate ◽  
Self Assembly ◽  
Hydroxyl Groups ◽  
Indentation Modulus ◽  
Layer By Layer ◽  
Carbonyl Groups ◽  
Flexible Material ◽  
Layer Technique ◽  
Brick And Mortar

Abstract "Mortar" and "brick" structure is a general model to construct nanocomposites. A film with "brick-and-mortar" structure was prepared by LBL (Layer-by-Layer) technique using polyvinyl alcohol (PVA) and polymethyl methacrylate (PMMA) as the flexible material or "mortar" and mica as the rigid material or "brick". The film deposited on a glass slide after self-assembly cycles was ~3μm thick with an uneven, wavy surface. The film showed enhanced mechanical properties with the hardness and indentation modulus values up to 6.14 GPa and 68.41 GPa, respectively. It was found that the hardness and elastic toughness depended on the ratio of mica, the number of self-assembly cycles, and the pretreatment method of the mica suspension. The self-assembly process was believed to be attributable to the hydrogen bonds between the silanol groups of mica and the hydroxyl groups of PVA and carbonyl groups of PMMA.

Evaluation of geometrical benchmark artifacts containing multiple overhang lengths fabricated using material extrusion technique

2020 ◽  
Vol 14 (3) ◽  
pp. 7296-7308
Author(s):  
Siti Nur Humaira Mazlan ◽  
Aini Zuhra Abdul Kadir ◽  
N. H. A. Ngadiman ◽  
M.R. Alkahari
Keyword(s):  
3D Model ◽  
Laser Scanner ◽  
Dimensional Accuracy ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Layer Technique ◽  
Subtractive Manufacturing ◽  
Manufacturing Features ◽  
Layer Problem

Fused deposition modelling (FDM) is a process of joining materials based on material entrusion technique to produce objects from 3D model using layer-by-layer technique as opposed to subtractive manufacturing. However, many challenges arise in the FDM-printed part such as warping, first layer problem and elephant food that was led to an error in dimensional accuracy of the printed parts especially for the overhanging parts. Hence, in order to investigate the manufacturability of the FDM printed part, various geometrical and manufacturing features were developed using the benchmarking artifacts. Therefore, in this study, new benchmarking artifacts containing multiple overhang lengths were proposed. After the benchmarking artifacts were developed, each of the features were inspected using 3D laser scanner to measure the dimensional accuracy and tolerances. Based on 3D scanned parts, 80% of the fabricated parts were fabricated within ±0.5 mm of dimensional accuracy as compared with the CAD data. In addition, the multiple overhang lengths were also successfully fabricated with a very significant of filament sagging observed.

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