Layer-by-Layer Technology and Its Implications in the Field of Glucose Nanobiosensors

2015 ◽  
pp. 400-437
Author(s):  
Sharath P. Sasi
Keyword(s):  
Glucose Sensors ◽  
Layer By Layer ◽  
Fluorescent Biosensors ◽  
Glucose Levels ◽  
Non Invasive ◽  
Sensor Membrane ◽  
Lbl Assembly ◽  
Cause Of Deaths ◽  
History Of ◽  
Assembly Technology

Diabetes is the seventh leading cause of deaths in the US with almost 439 million people worldwide expected to be diabetic by 2030. The need for continuous, non-invasive monitoring is a top priority. Earlier devices that utilized electroenzymatic sensing technique were minimally invasive and had major pitfalls. Advancements in various non-invasive, especially fluorescence-based, sensing along with developments in LBL assembly have resulted in a new breed of micro/nanosensors that are implantable, reliable, reproducible, mechanically and functionally stable, responsive, and miniaturized. In this chapter, the authors discuss the history of glucose sensors, evolution over the past four decades, methods employed to detect glucose levels in fluorescent biosensors, and assays that can be fabricated on to the sensor membrane, immobilized into the membrane as multilayers, or encapsulated within micro/nanocapsules using LBL assembly technology. The authors briefly review the various materials available and currently implemented for fabrication of glucose biosensors using LBL assembly.

scholarly journals Correlation of Montmorillonite Sheet Thickness and Flame Retardant Behavior of a Chitosan–Montmorillonite Nanosheet Membrane Assembled on Flexible Polyurethane Foam

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 213 ◽  
Author(s):  
Peng Chen ◽  
Yunliang Zhao ◽  
Wei Wang ◽  
Tingting Zhang ◽  
Shaoxian Song
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Sheet Thickness ◽  
Wall Structure ◽  
Layer By Layer ◽  
Lbl Assembly ◽  
Assembly Technology ◽  
Flexible Polyurethane Foam ◽  
Flexible Polyurethane ◽  
Different Thickness

Polymer–clay membranes constructed via the layer-by-layer (LbL) assembly, with a nanobrick wall structure, are known to exhibit high flame retardancy. In this work, chitosan–montmorillonite nanosheet (CH–MMTNS) membranes with different thickness of MMTNS were constructed to suppress the flammability of flexible polyurethane (FPU) foam. It was found that a thinner MMTNS membrane was more efficient in terms of reducing the flammability of the FPU foam. This was because such MMTNS membrane could deposit cheek by jowl and form a dense CH–MMTNS membrane on the foam surface, thus greatly limiting the translation of heat, oxygen, and volatile gases. In contrast, a thicker MMTNS constructed a fragmentary CH–MMTNS membrane on the coated foam surface, due to its greater gravity and weaker electrostatic attraction of chitosan; thus, the flame retardancy of a thick MMTNS membrane was lower. Moreover, the finding of different deposition behaviors of MMTNS membranes with different thickness may suggest improvements for the application of clay with the LbL assembly technology.

Layer-by-layer (LBL) assembly technology as promising strategy for tailoring pressure-driven desalination membranes

2015 ◽  
Vol 493 ◽  
pp. 428-443 ◽  
Author(s):  
Guo-Rong Xu ◽  
Sheng-Hui Wang ◽  
He-Li Zhao ◽  
Shui-Bo Wu ◽  
Jian-Mei Xu ◽  
...  
Keyword(s):  
Layer By Layer ◽  
Lbl Assembly ◽  
Promising Strategy ◽  
Assembly Technology ◽  
Pressure Driven

scholarly journals Preparation of Layer-by-Layer Nanofiltration Membranes by Dynamic Deposition and Crosslinking

Membranes ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 20 ◽  
Author(s):  
Yan Liu ◽  
George Chen ◽  
Xiuli Yang ◽  
Huining Deng
Keyword(s):  
Membrane Surface ◽  
Deposition Process ◽  
Separation Performance ◽  
Layer By Layer ◽  
Good Separation ◽  
Membrane Performance ◽  
Polyelectrolyte Membranes ◽  
Lbl Assembly ◽  
Charge Property ◽  
Assembly Technology

In recent decades, the advancements in layer-by-layer (LBL) assembly technology have provoked increasing interest in the preparation of multilayer polyelectrolyte membranes with excellent performance. In the current study, a novel nanofiltration (NF) membrane was prepared by pressure-driven layer-by-layer (LBL) assembly of polyethylenimine (PEI) and polyacrylicacid (PAA) on a porous substrate with chemical crosslinking. The effect of deposition pressure on separation performance of the prepared membranes was studied. The surface morphology, hydrophilicity and the charge property of the dynamically-deposited membranes were compared with those prepared by static adsorption. The characterization results showed that dynamic deposition process resulted in a smoother membrane surface with improved hydrophilicity. The mechanism of water-path formation was proposed to interpret the effect of pressure on the membrane performance. Glutaraldehyde (GA) was used as a crosslinker to reduce the number of polyelectrolyte bilayers for obtaining good separation performance. The rejections of different inorganic salts of the dynamically-deposited NF membrane were also investigated.

Characterization and Biocompatibility Studies of Layer-by-Layer Self-Assembled Humic Acid/Fe3+ Films

2000 ◽  
Vol 662 ◽  
Author(s):  
Izabela Galeska ◽  
Tammy Hickey ◽  
Francis Moussy ◽  
Fotios Papadimitrakopoulos
Keyword(s):  
Self Assembly ◽  
Strong Dependence ◽  
Tissue Reaction ◽  
Glucose Sensors ◽  
Layer By Layer ◽  
Degree Of Ionization ◽  
Glucose Levels ◽  
Silastic Tubing ◽  
Assembly Technique

AbstractA semipermeable and non-inflammatory membrane is a prerequisite for the development of an implantable biosensor for continuous pain free monitoring of glucose levels in vivo. Humic acids (HAs) have been reported to have therapeutically relevant characteristics such as antiviral and anti-inflammatory.[1] This encouraged us to investigate the in vivo compatibility of HAs based multilayered films as a potential membrane material for implantable glucose sensors. Electrostatic layer-by-layer self-assembly technique of HAs with oppositely charged ferric ions was utilized to grow these films. Quartz Crystal Microbalance (QCM) and ellipsometric studies have shown repeatable, stepwise increase in mass and in film thickness during self-assembly. The growth of these assemblies exhibited strong dependence on pH and ionic strength of HAs solution and was correlated with the degree of ionization of carboxyl groups and the neutralization induced surface spreading. HAs films used in the biocompatibility study were very well tolerated by the tissue and no difference with silastic tubing, used as control, could be observed. All types of samples, including the controls, induced similar long-term tissue reaction showing almost no inflammation and a light to moderate fibrosis with some blood vessels present.

scholarly journals Recent Progress and Perspectives on Non-Invasive Glucose Sensors

Diabetology ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 56-71
Author(s):  
Nicholas B. Davison ◽  
Christopher J. Gaffney ◽  
Jemma G. Kerns ◽  
Qiandong D. Zhuang
Keyword(s):  
Optical Sensors ◽  
Technology Development ◽  
Optical Sensing ◽  
Glucose Monitoring ◽  
Glucose Sensing ◽  
Glucose Sensors ◽  
Monitoring Methods ◽  
Glucose Levels ◽  
Non Invasive ◽  
Wide Range

Self-monitoring of blood glucose forms an important part of the management of diabetes and the prevention of hyperglycaemia and hypoglycaemia. Current glucose monitoring methods either use needle-prick enzymatic glucose-meters or subcutaneous continuous glucose sensors (CGM) and thus, non-invasive glucose measurements could greatly improve the self-management of diabetes. A wide range of non-invasive sensing techniques have been reported, though achieving a level of precision comparable to invasive meters remains a challenge. Optical sensors, which utilise the interactions between glucose and light, offer the potential for non-invasive continuous sensing, allowing real-time monitoring of glucose levels, and a range of different optical sensing technologies have been proposed. These are primarily based upon optical absorption and scattering effects and include infrared spectroscopy, Raman spectroscopy and optical coherence tomography (OCT), with other optical techniques such as photoacoustic spectroscopy (PAS) and polarimetry also reported. This review aims to discuss the current progress behind the most reported optical glucose sensing methods, theory and current limitations of optical sensing methods and the future technology development required to achieve an accurate optical-based glucose monitoring device.

Research Progress on Non-Invasive Glucose Monitoring Based on Reverse Iontophoresis

2012 ◽  
Vol 529 ◽  
pp. 361-365 ◽  
Author(s):  
Yang Yang Liu ◽  
Hong Wang ◽  
Jian Guo Cui ◽  
Ji Yu Wu ◽  
Xiao Jing Yao
Keyword(s):  
Glucose Monitoring ◽  
Glucose Sensors ◽  
The Other ◽  
Research Progress ◽  
Tissue Fluid ◽  
Reverse Iontophoresis ◽  
Low Level ◽  
Glucose Levels ◽  
Non Invasive ◽  
Precision And Accuracy

To research the glucose levels with diabetes to reduce complications, a method which is about the noninvasive glucose monitoring based on the reverse iontophoresis has been introduced. This paper summarizes the theory of reverse iontophoresis as well as the method of tissue fluid’s extraction, and reviewed the research progress on non-invasive glucose monitoring based on the principle of the reverse iontophoresis,and investigated glucose sensors for low level glucose monitoring, pointed out the other elements detection based on the iontophoresis method in tissue fluid. The technology based on reverse iontophoresis could be the most possible method to detect glucose noninvasively, moreover the precision and accuracy of the GlucoWatch could be improved in the future.

scholarly journals Improving the Flame Retardancy of Bamboo Slices by Coating With Melamine–Phytate via Layer-by-Layer Assembly

2021 ◽  
Vol 8 ◽  
Author(s):  
Peng Lin ◽  
Yuchen Xu ◽  
Junfeng Hou ◽  
Xiaochun Zhang ◽  
Lingfei Ma ◽  
...  
Keyword(s):  
Flame Retardancy ◽  
Vital Role ◽  
Asia Pacific ◽  
Layer By Layer ◽  
Natural Polymer ◽  
Release Rates ◽  
X Ray ◽  
Lbl Assembly ◽  
Rich Natural Resource ◽  
Assembly Technology

Bamboo is a rich natural resource in the Asia Pacific, and it is widely used in the construction and decoration industry. Meanwhile, bamboo is an extremely combustible natural polymer material. Herein, the bamboo slices were treated with melamine and phytic acid using layer-by-layer (LBL) assembly technology to improve their flame retardancy properties. The morphology and chemical composition of untreated and treated bamboo slices were measured by scanning electron microscopy equipped with energy dispersive X-ray analysis and Fourier transform infrared spectra. The results showed that two-dimensional melamine–phytate (MP) nanoflakes were successfully formed and deposited on the bamboo surface. The deposition of the MP coating caused the earlier degradation of the bamboo to form char, according to thermogravimetric analysis. The peak heat release rates of the treated bamboo slices were reduced by more than 28% compared to those of the untreated ones. The MP coating promoted the formation of thermally stable char, which was responsible for the significant improvement in flame retardancy. Besides, the char layer with excellent thermal resistance performed a vital role in suppressing flame spread.

Study of Diabetic Mellitus and Knowledge of Lotion Foot Care on the Community

2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Hariyadi DM ◽  
Athiyah U ◽  
Hendradi E ◽  
Rosita N ◽  
Erawati T ◽  
...  
Keyword(s):  
Blood Glucose ◽  
T Test ◽  
Small Scale ◽  
Scale Production ◽  
Foot Care ◽  
Diabetic Mellitus ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Before And After ◽  
History Of

The prevention of Diabetic Mellitus (DM) and its complications is the main aim of this study, in addition to the training of lotion foot care application and the development of small scale industry. The research team delivered knowledge in the form of training on Diabetic Mellitus, healthy food, treatment and prevention of complications, and small-scale production of cosmetic products. The aim of this study was to determine the correlation between training on diabetic and lotion foot care application as preventive measures against diabetic complications on the patient's blood glucose levels in the community of residents in Banyuurip Jaya, Surabaya. It was expected from this training that the knowledge of the residents increases and people living with diabetic undergo lifestyle changes and therefore blood sugar levels can be controlled. The parameters measured in this research were blood glucose levels, the anti diabetic drug types consumed, and compliance on diabetics. This study used the data taken from 60 patients with DM over a period of one month. Questionnaires and log books was used to retrieve data and changes in blood glucose levels in diabetic patients. The results showed the demographic data of patients with type 2 diabetic of 85% female and 15% male, with the range of patients aged of 61-70 years of 46.67% and had history of diabetic (90%). The history of drugs consumed by respondents was anti diabetic drugs such as metformin (40%), glimepiride (33.37%) and insulin (6.67%). In addition, the increased knowledge of DM patients after being given the training compared to before training was shown in several questions in the questionnaire. A statistical analysis using t-test analyzed a correlation between training provided in order to enhance understanding of the patient, as well as correlation with blood glucose levels. A paired T-test showed that there was a relationship between the knowledge of trainees before and after training (p less than 0.05). An interesting result was that there was no relationship between blood glucose levels before and after training provided (p> 0.05).

scholarly journals Construction of Chitosan/Alginate Nano-Drug Delivery System for Improving Dextran Sodium Sulfate-Induced Colitis in Mice

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1884
Author(s):  
Mengfei Jin ◽  
Shangyong Li ◽  
Yanhong Wu ◽  
Dandan Li ◽  
Yantao Han
Keyword(s):  
Self Assembly ◽  
Average Diameter ◽  
Mucosal Healing ◽  
Plga Nanoparticles ◽  
Narrow Particle Size Distribution ◽  
Layer By Layer ◽  
Systemic Side Effects ◽  
Assembly Technology ◽  
The Fourier Transform ◽  
Polyelectrolyte Film

(1) Background: In the treatment of ulcerative colitis (UC), accurate delivery and release of anti-inflammatory drugs to the site of inflammation can reduce systemic side effects. (2) Methods: We took advantage of this goal to prepare resveratrol-loaded PLGA nanoparticles (RES-PCAC-NPs) by emulsification solvent volatilization. After layer-by-layer self-assembly technology, we deposited chitosan and alginate to form a three-layer polyelectrolyte film. (3) Results: It can transport nanoparticles through the gastric environment to target inflammation sites and slowly release drugs at a specific pH. The resulting RES-PCAC-NPs have an ideal average diameter (~255 nm), a narrow particle size distribution and a positively charged surface charge (~13.5 mV). The Fourier transform infrared spectroscopy showed that resveratrol was successfully encapsulated into PCAC nanoparticles, and the encapsulation efficiency reached 87.26%. In addition, fluorescence imaging showed that RES-PCAC-NPs with positive charges on the surface can effectively target and accumulate in the inflammation site while continuing to penetrate downward to promote mucosal healing. Importantly, oral RES-PCAC-NPs treatment in DSS-induced mice was superior to other results in significantly improved inflammatory markers of UC. (4) Conclusions: Our results strongly prove that RES-PCAC-NPs can target the inflamed colon for maximum efficacy, and this oral pharmaceutical formulation can represent a promising formulation in the treatment of UC.

scholarly journals Architectural ruins: geoculture of the anatomy of buildings as illustrated by Casa Ippolito, Malta

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Lino Bianco
Keyword(s):  
Material Culture ◽  
Building Materials ◽  
Raw Materials ◽  
Primary Source ◽  
Secondary Sources ◽  
Non Invasive ◽  
History Of ◽  
Aerial Vehicle ◽  
Materials Used ◽  
Building Physics

AbstractRuins are a statement on the building materials used and the construction method employed. Casa Ippolito, now in ruins, is typical of 17th-century Maltese aristocratic country residences. It represents an illustration of secondary or anthropogenic geodiversity. This paper scrutinises these ruins as a primary source in reconstructing the building’s architecture. The methodology involved on-site geographical surveying, including visual inspection and non-invasive tests, a geological survey of the local lithostratigraphy, and examination of notarial deeds and secondary sources to support findings about the building’s history as read from its ruins. An unmanned aerial vehicle was used to digitally record the parlous state of the architectural structure and karsten tubes were used to quantify the surface porosity of the limestone. The results are expressed from four perspectives. The anatomy of Casa Ippolito, as revealed in its ruins, provides a cross-section of its building history and shows two distinct phases in its construction. The tissue of Casa Ippolito—the building elements and materials—speaks of the knowledge of raw materials and their properties among the builders who worked on both phases. The architectural history of Casa Ippolito reveals how it supported its inhabitants’ wellbeing in terms of shelter, water and food. Finally, the ruins in their present state bring to the fore the site’s potential for cultural tourism. This case study aims to show that such ruins are not just geocultural remains of historical built fabric. They are open wounds in the built structure; they underpin the anatomy of the building and support insights into its former dynamics. Ruins offer an essay in material culture and building physics. Architectural ruins of masonry structures are anthropogenic discourse rendered in stone which facilitate not only the reconstruction of spaces but also places for human users; they are a statement on the wellbeing of humanity throughout history.

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