scholarly journals Janus Hydrogel Microbeads for Glucose Sensing with pH Calibration

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4829
Author(s):  
Maru Ando ◽  
Mio Tsuchiya ◽  
Shun Itai ◽  
Tomomi Murayama ◽  
Yuta Kurashina ◽  
...  
Keyword(s):  
Body Fluid ◽  
Glucose Monitoring ◽  
Glucose Sensing ◽  
Implantable Sensors ◽  
Proof Of Concept ◽  
Ph Sensors ◽  
Ph Values ◽  
Fluorescent Microbeads ◽  
Ph Conditions ◽  
Ph Calibration

We present fluorescent Janus hydrogel microbeads for continuous glucose sensing with pH calibration. The Janus hydrogel microbeads, that consist of fluorescent glucose and pH sensors, were fabricated with a UV-assisted centrifugal microfluidic device. The microbead can calibrate the pH values of its surroundings and enables accurate measurements of glucose within various pH conditions. As a proof of concept, we succeeded in obtaining the accurate value of glucose concentration in a body-fluid-like sample solution. We believe that our fluorescent microbeads, with pH calibration capability, could be applied to fully implantable sensors for continuous glucose monitoring.

scholarly journals Microfluidic single-cell scale-down bioreactors: A proof-of-concept for the growth of Corynebacterium glutamicum at oscillating pH values

2021 ◽  
Author(s):  
Sarah Täuber ◽  
Luisa Blöbaum ◽  
Valentin Steier ◽  
Marco Oldiges ◽  
Alexander Grünberger
Keyword(s):  
Single Cell ◽  
Corynebacterium Glutamicum ◽  
Large Scale ◽  
Detailed Comparison ◽  
Proof Of Concept ◽  
Application Range ◽  
Ph Values ◽  
Scale Down ◽  
Ph Conditions

In large-scale bioreactors, gradients in cultivation parameters such as oxygen, substrate and pH result in fluctuating environments. pH fluctuations were identified as a critical parameter for bioprocess performance. Traditionally, scale-down systems at the laboratory scale are used to analyze the effects of fluctuating pH values on strain and thus process performance. Here, we demonstrate the application of dynamic microfluidic single-cell cultivation (dMSCC) as a novel scale-down system for the characterization of Corynebacterium glutamicum growth using oscillating pH conditions as a model parameter. A detailed comparison between two-compartment reactor (two-CR) scale-down experiments and dMSCC was performed for one specific pH oscillation between reference pH 7 (~8 min) and disturbed pH 6 (~2 min). Similar reductions in growth rates were observed in both systems (dMSCC 21% and two-CR 27%). Afterward, systematic experiments at different symmetric and asymmetric pH oscillations between pH ranges of 4 −6 and 8 −11 and different intervals from 1 minute to 20 minutes, were performed to demonstrate the unique application range and throughput of the dMSCC system. Finally, the strength of the dMSCC application was demonstrated by mimicking fluctuating environmental conditions within large-scale bioprocesses, which is difficult to conduct using two-CRs.

Glucose Sensing in Transdermal Body Fluid Collected Under Continuous Vacuum Pressure Via Micropores in the Stratum Corneum

2003 ◽  
Vol 5 (2) ◽  
pp. 159-166 ◽  
Author(s):  
Suzanne Gebhart ◽  
Mark Faupel ◽  
Richard Fowler ◽  
Candis Kapsner ◽  
Daniel Lincoln ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Body Fluid ◽  
Glucose Sensing ◽  
Vacuum Pressure ◽  
Continuous Vacuum

scholarly journals A Review of Non-Invasive Optical Systems for Continuous Blood Glucose Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6820
Author(s):  
Bushra Alsunaidi ◽  
Murad Althobaiti ◽  
Mahbubunnabi Tamal ◽  
Waleed Albaker ◽  
Ibraheem Al-Naib
Keyword(s):  
Blood Glucose ◽  
Glucose Monitoring ◽  
Daily Basis ◽  
Glucose Sensing ◽  
Blood Glucose Monitoring ◽  
Optical Systems ◽  
Glucose Levels ◽  
Non Invasive ◽  
Blood Glucose Levels ◽  
Continuous Blood Glucose Monitoring

The prevalence of diabetes is increasing globally. More than 690 million cases of diabetes are expected worldwide by 2045. Continuous blood glucose monitoring is essential to control the disease and avoid long-term complications. Diabetics suffer on a daily basis with the traditional glucose monitors currently in use, which are invasive, painful, and cost-intensive. Therefore, the demand for non-invasive, painless, economical, and reliable approaches to monitor glucose levels is increasing. Since the last decades, many glucose sensing technologies have been developed. Researchers and scientists have been working on the enhancement of these technologies to achieve better results. This paper provides an updated review of some of the pioneering non-invasive optical techniques for monitoring blood glucose levels that have been proposed in the last six years, including a summary of state-of-the-art error analysis and validation techniques.

scholarly journals Optimal pH in chlorinated swimming pools – balancing formation of by-products

2013 ◽  
Vol 11 (3) ◽  
pp. 465-472 ◽  
Author(s):  
Kamilla M. S. Hansen ◽  
Hans-Jørgen Albrechtsen ◽  
Henrik R. Andersen
Keyword(s):  
Body Fluid ◽  
Product Formation ◽  
Swimming Pools ◽  
Batch Experiments ◽  
Ph Values ◽  
Precursor Ratio ◽  
Decreasing Ph ◽  
Ph Range ◽  
By Products ◽  
Optimal Ph

In order to identify the optimal pH range for chlorinated swimming pools, the formation of trihalomethanes, haloacetonitriles and trichloramine was investigated in the pH-range 6.5–7.5 in batch experiments. An artificial body fluid analogue was used to simulate bather load as the precursor for by-products. The chlorine-to-precursor ratio used in the batch experiments influenced the amounts of by-products formed, but regardless of the ratio the same trends in the effect of pH were observed. Trihalomethane formation was reduced by decreasing pH, but haloacetonitrile and trichloramine formation increased. To evaluate the significance of the increase and decrease of the investigated organic by-products at the different pH values, the genotoxicity was calculated based on literature values. The calculated genotoxicity was approximately at the same level in the pH range 6.8–7.5 and increased when pH was 6.7 or lower. An optimal pH range for by-products formation in swimming pools was identified at pH 7.0–7.2. In the wider pH range (pH 6.8–7.5), the effect on by-product formation was negligible. Swimming pools should never be maintained at lower pH than 6.8 since formation of both haloacetonitriles and trichloramine increase significantly below this value.

scholarly journals Accuracy of flash glucose monitoring and continuous glucose monitoring technologies: Implications for clinical practice

2018 ◽  
Vol 15 (3) ◽  
pp. 175-184 ◽  
Author(s):  
Ramzi A Ajjan ◽  
Michael H Cummings ◽  
Peter Jennings ◽  
Lalantha Leelarathna ◽  
Gerry Rayman ◽  
...  
Keyword(s):  
Continuous Glucose Monitoring ◽  
Diabetes Care ◽  
Interstitial Fluid ◽  
Glucose Monitoring ◽  
Relative Difference ◽  
Glucose Sensing ◽  
Sensor Data ◽  
Flash Glucose Monitoring ◽  
Fluid Sensor ◽  
Monitoring Technologies

Continuous glucose monitoring and flash glucose monitoring technologies measure glucose in the interstitial fluid and are increasingly used in diabetes care. Their accuracy, key to effective glycaemic management, is usually measured using the mean absolute relative difference of the interstitial fluid sensor compared to reference blood glucose readings. However, mean absolute relative difference is not standardised and has limitations. This review aims to provide a consensus opinion on assessing accuracy of interstitial fluid glucose sensing technologies. Mean absolute relative difference is influenced by glucose distribution and rate of change; hence, we express caution on the reliability of comparing mean absolute relative difference data from different study systems and conditions. We also review the pitfalls associated with mean absolute relative difference at different glucose levels and explore additional ways of assessing accuracy of interstitial fluid devices. Importantly, much data indicate that current practice of assessing accuracy of different systems based on individualised mean absolute relative difference results has limitations, which have potential clinical implications. Healthcare professionals must understand the factors that influence mean absolute relative difference as a metric for accuracy and look at additional assessments, such as consensus error grid analysis, when evaluating continuous glucose monitoring and flash glucose monitoring systems in diabetes care. This in turn will ensure that management decisions based on interstitial fluid sensor data are both effective and safe.

Solubility of Iron in Model Systems Containing Organic Acids and Lignin

1992 ◽  
Vol 55 (11) ◽  
pp. 893-898 ◽  
Author(s):  
TAKESHI SUZUKI ◽  
FERGUS M. CLYDESDALE ◽  
TIRA PANDOLF
Keyword(s):  
Ascorbic Acid ◽  
Organic Acids ◽  
Model Systems ◽  
Molar Ratio ◽  
Soluble Form ◽  
Enhancing Effect ◽  
Gastrointestinal Ph ◽  
Soluble Iron ◽  
Ph Values ◽  
Ph Conditions

The effect of six organic acids, ascorbic, citric, fumaric, lactic, malic, and succinic, alone and in combination, at a 1:1.9 molar ratio (Fe+2:ligand) on the solubility of iron was evaluated in the presence of lignin under simulated gastrointestinal pH conditions. The enhancing effect, evaluated under two systems of preparation at two pH values, was in the following order: citric>malic>ascorbic>lactic,fumaric>succinic. Citric acid solubilized 80 and 81% of iron under both pH conditions. When ascorbic acid was mixed with fumaric, lactic, and succinic acids, a higher percentage of soluble iron was retained than with these three acids alone. In the case of citric and malic acids, the addition of ascorbic acid reduced the soluble iron. The percentage of soluble iron obtained when prepared at the endogenous pH (2.5–3.1) was higher than that at pH 5.5. These results indicated that ascorbate bound less iron in a soluble form than citrate or malate but more than fumarate, lactate, or succinate. Also, combinations of citric with malic acid did not demonstrate a synergistic effect.

scholarly journals Oxaliplatin–Biomimetic Magnetic Nanoparticle Assemblies for Colon Cancer-Targeted Chemotherapy: An In Vitro Study

Pharmaceutics ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 395 ◽  
Author(s):  
Ylenia Jabalera ◽  
Beatriz Garcia-Pinel ◽  
Raul Ortiz ◽  
Guillermo Iglesias ◽  
Laura Cabeza ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Electrostatic Interactions ◽  
Magnetic Nanoparticle ◽  
In Vitro Study ◽  
Targeted Chemotherapy ◽  
Proof Of Concept ◽  
Therapeutic Approaches ◽  
Ph Values ◽  
Common Cancer

Conventional chemotherapy against colorectal cancer (CRC), the third most common cancer in the world, includes oxaliplatin (Oxa) which induces serious unwanted side effects that limit the efficiency of treatment. Therefore, alternative therapeutic approaches are urgently required. In this work, biomimetic magnetic nanoparticles (BMNPs) mediated by MamC were coupled to Oxa to evaluate the potential of the Oxa–BMNP nanoassembly for directed local delivery of the drug as a proof of concept for the future development of targeted chemotherapy against CRC. Electrostatic interactions between Oxa and BMNPs trigger the formation of the nanoassembly and keep it stable at physiological pH. When the BMNPs become neutral at acidic pH values, the Oxa is released, and such a release is greatly potentiated by hyperthermia. The coupling of the drug with the BMNPs improves its toxicity to even higher levels than the soluble drug, probably because of the fast internalization of the nanoassembly by tumor cells through endocytosis. In addition, the BMNPs are cytocompatible and non-hemolytic, providing positive feedback as a proof of concept for the nanoassembly. Our study clearly demonstrates the applicability of Oxa–BMNP in colon cancer and offers a promising nanoassembly for targeted chemotherapy against this type of tumor.

Coagulation-Direct Filtration of Soft, Low Alkalinity Humic Waters

1999 ◽  
Vol 40 (9) ◽  
pp. 55-62 ◽  
Author(s):  
Bjørnar Eikebrokk
Keyword(s):  
Natural Organic Matter ◽  
Pilot Scale ◽  
Quality Parameters ◽  
Efficient Removal ◽  
Direct Filtration ◽  
Ph Values ◽  
Optimum Ph ◽  
Calcium Sources ◽  
Ph Conditions ◽  
Removal Efficiencies

Optimisation of coagulation-direct filtration processes with respect to efficient removal of humic substances, i.e. natural organic matter (NOM) has gained a lot of focus in many countries over the last years. This paper presents experimental results from pilot scale research studies aimed at optimising the coagulation-direct filtration process applied to soft and humic raw waters with low turbidity and alkalinity levels. Comprehensive tests of 3 types of raw waters with different NOM content, 5 types of coagulants, and 3 calcium sources for the purpose of corrosion control have been conducted. Removal efficiencies with respect to relevant water quality parameters are presented, with typical relationships between raw water NOM content, coagulant dose requirements and pH. Generally, when applying metal-based coagulants, residual metal concentration was the critical parameter regarding minimum coagulant dose requirements. Typical NOM removal efficiencies were in the range of 75-90% and 40-70% with respect to colour and organic carbon, respectively. Optimum pH conditions for the removal of NOM and/or residual metals do not always coincide with that of turbidity. The experiments also showed that poly-aluminium and ferric chlorides might have some benefits over alum in terms of dose requirements and range of optimum pH values, and that chitosan may be used for colour removal with good results.

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