Covalent Immobilisation of a Nanoporous Platinum Film onto a Gold Screen-Printed Electrode for Highly Stable and Selective Non-Enzymatic Glucose Sensing

Progress in the development of commercially available non-enzymatic glucose sensors continues to be problematic due to issues regarding selectivity, reproducibility and stability. Overcoming these issues is a research challenge of significant importance. This study reports a novel fabrication process using a double-layer self-assembly of (3 mercaptopropyl)trimethoxysilane (MPTS) on a gold substrate and co-deposition of a platinum–copper alloy. The subsequent electrochemical dealloying of the less noble copper resulted in a nanoporous platinum structure on the uppermost exposed thiol groups. Amperometric responses at 0.4 V vs. Ag/AgCl found the modification to be highly selective towards glucose in the presence of known interferants. The sensor propagated a rapid response time <5 s and exhibited a wide linear range from 1 mM to 18 mM. Additionally, extremely robust stability was attributed to enhanced attachment due to the strong chemisorption between the gold substrate and the exposed thiol of MPTS. Incorporation of metallic nanomaterials using the self-assembly approach was demonstrated to provide a more reproducible and controlled molecular architecture for sensor fabrication. The successful application of the sensor in real blood serum samples displayed a strong correlation with clinically obtained glucose levels.

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The Mechanism of Jian-Gan-Xiao-Zhi Decoction in Insulin Resistant Adipocytes and Its Component Analysis

Natural Product Communications ◽

10.1177/1934578x21997678 ◽

2021 ◽

Vol 16 (3) ◽

pp. 1934578X2199767

Author(s):

Fang Fang ◽

Wei-Bo Wen ◽

Xue-Hua Xie ◽

Ling Yang ◽

Xu Zhang ◽

...

Keyword(s):

Lipid Synthesis ◽

Glucose Consumption ◽

Astragaloside Iv ◽

Serum Samples ◽

Rat Serum ◽

Jnk Pathway ◽

Alcoholic Fatty Liver ◽

Insulin Resistant ◽

Glucose Levels ◽

Main Components

Background: Jian-Gan-Xiao-Zhi decoction (JGXZ) is a traditional Chinese medicine formula to treat patients with non-alcoholic fatty liver disease (NAFLD). The study aimed to analyze the mechanism of JGXZ in adipocytes and detect the main components of the drug in rat serum. Methods: 3T3-L1 preadipocytes were used to establish an insulin resistant (IR) adipocyte model. Lipid accumulation in adipocytes was detected by oil red O staining. After JGXZ treatment, glucose consumption, total cholesterol (TC), and triglyceride (TG) were analyzed using the corresponding kits. ROS levels were measured by flow cytometry. In addition, Western blot was used to assess LKB1/AMPK and JNK/IRS/PI3k/AKT expressions. The main components of JGXZ in rat serum samples were detected by LC-MS/MS using a Phenomenex Luna C18 column, a mobile phase of methanol and 0.1% formic acid solution, and ESI detection. Results: JGXZ significantly decreased glucose levels and adipogenesis, accompanied by decreased IR ( P < 0.01). Besides, JGXZ markedly affected ROS, LKB1/AMPK, and JNK/IRS/PI3k/AKT levels ( P < 0.01). R1, Rg1, paeoniflorin, Rb1, astragaloside IV, and tanshinone could be significantly quantified. Conclusions: JGXZ decreased glucose and lipid synthesis, possibly via the ROS/AMPK/JNK pathway. R1, Rg1, paeoniflorin, Rb1, astragaloside IV, and tanshinone in JGXZ could play major roles in treating NAFLD, which could assist in the study of the mechanism of JGXZ in treating NAFLD.

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Luminescent Supramolecular Nano- or Microstructures Formed in Aqueous Media by Amphiphile-Noble Metal Complexes

Journal of Nanomaterials ◽

10.1155/2020/5395048 ◽

2020 ◽

Vol 2020 ◽

pp. 1-24 ◽

Cited By ~ 1

Author(s):

Carmen Cretu ◽

Loredana Maiuolo ◽

Domenico Lombardo ◽

Elisabeta I. Szerb ◽

Pietro Calandra

Keyword(s):

Noble Metal ◽

Smart Materials ◽

Self Assembly ◽

Noble Metals ◽

Photophysical Properties ◽

Aqueous Media ◽

Molecular Architecture ◽

Stimuli Responsive ◽

Panoramic View ◽

Amphiphilic Molecules

The involvement of metal ions within the self-assembly spontaneously occurring in surfactant-based systems gives additional and interesting features. The electronic states of the metal, together with the bonds that can be established with the organic amphiphilic counterpart, are the factors triggering new photophysical properties. Moreover, the availability of stimuli-responsive supramolecular amphiphile assemblies, able to disassemble in a back-process, provides reversible switching particularly useful in novel approaches and applications giving rise to truly smart materials. In particular, small amphiphiles with an inner distribution, within their molecular architecture, of various polar and apolar functional groups, can give a wide variety of interactions and therefore enriched self-assemblies. If it is joined with the opportune presence and localization of noble metals, whose chemical and photophysical properties are undiscussed, then very interesting materials can be obtained. In this minireview, the basic concepts on self-assembly of small amphiphilic molecules with noble metals are shown with particular reference to the photophysical properties aiming at furnishing to the reader a panoramic view of these exciting problematics. In this respect, the following will be shown: (i) the principles of self-assembly of amphiphiles that involve noble metals, (ii) examples of amphiphiles and amphiphile-noble metal systems as representatives of systems with enhanced photophysical properties, and (iii) final comments and perspectives with some examples of modern applications.

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Self-Assembly, Symmetry, and Molecular Architecture: Coordination as the Motif in the Rational Design of Supramolecular Metallacyclic Polygons and Polyhedra

Accounts of Chemical Research ◽

10.1021/ar9602011 ◽

1997 ◽

Vol 30 (12) ◽

pp. 502-518 ◽

Cited By ~ 906

Author(s):

Peter J. Stang ◽

Bogdan Olenyuk

Keyword(s):

Self Assembly ◽

Rational Design ◽

Molecular Architecture

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Insulin blunts the response of glucose-excited neurons in the ventrolateral-ventromedial hypothalamic nucleus to decreased glucose

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.90932.2008 ◽

2009 ◽

Vol 296 (5) ◽

pp. E1101-E1109 ◽

Cited By ~ 37

Author(s):

Victoria E. Cotero ◽

Vanessa H. Routh

Keyword(s):

Energy Homeostasis ◽

Ventromedial Hypothalamus ◽

Glucose Sensing ◽

Hypothalamic Nucleus ◽

Compensatory Mechanisms ◽

Glucose Levels ◽

Compound C ◽

Obesity And Diabetes ◽

Extracellular Glucose ◽

Pi3k Signaling Pathway

Insulin signaling is dysfunctional in obesity and diabetes. Moreover, central glucose-sensing mechanisms are impaired in these diseases. This is associated with abnormalities in hypothalamic glucose-sensing neurons. Glucose-sensing neurons reside in key areas of the brain involved in glucose and energy homeostasis, such as the ventromedial hypothalamus (VMH). Our results indicate that insulin opens the KATP channel on VMH GE neurons in 5, 2.5, and 0.1 mM glucose. Furthermore, insulin reduced the sensitivity of VMH GE neurons to a decrease in extracellular glucose level from 2.5 to 0.1 mM. This change in the glucose sensitivity in the presence of insulin was reversed by the phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin (10 nM) but not by the mitogen-activated kinase (MAPK) inhibitor PD-98059 (PD; 50 μM). Finally, neither the AMPK inhibitor compound C nor the AMPK activator AICAR altered the activity of VMH GE neurons. These data suggest that insulin attenuates the ability of VMH GE neurons to sense decreased glucose via the PI3K signaling pathway. Furthermore, these data are consistent with the role of insulin as a satiety factor. That is, in the presence of insulin, glucose levels must decline further before GE neurons respond. Thus, the set point for detection of glucose deficit and initiation of compensatory mechanisms would be lowered.

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Two glucose sensing/signaling pathways stimulate glucose-induced inactivation of maltose permease in Saccharomyces.

Molecular Biology of the Cell ◽

10.1091/mbc.8.7.1293 ◽

1997 ◽

Vol 8 (7) ◽

pp. 1293-1304 ◽

Cited By ~ 38

Author(s):

H Jiang ◽

I Medintz ◽

C A Michels

Keyword(s):

Signaling Pathways ◽

Glucose Transport ◽

Glucose Sensor ◽

Constitutive Expression ◽

Glucose Sensing ◽

Regulation Of Transcription ◽

Carbohydrate Utilization ◽

Maltose Permease ◽

Glucose Levels ◽

Dependent Signal

Glucose is a global metabolic regulator in Saccharomyces. It controls the expression of many genes involved in carbohydrate utilization at the level of transcription, and it induces the inactivation of several enzymes by a posttranslational mechanism. SNF3, RGT2, GRR1 and RGT1 are known to be involved in glucose regulation of transcription. We tested the roles of these genes in glucose-induced inactivation of maltose permease. Our results suggest that at least two signaling pathways are used to monitor glucose levels. One pathway requires glucose sensor transcript and the second pathway is independent of glucose transport. Rgt2p, which along with Snf3p monitors extracellular glucose levels, appears to be the glucose sensor for the glucose-transport-independent pathway. Transmission of the Rgt2p-dependent signal requires Grr1p. RGT2 and GRR1 also play a role in regulating the expression of the HXT genes, which appear to be the upstream components of the glucose-transport-dependent pathway regulating maltose permease inactivation. RGT2-1, which was identified as a dominant mutation causing constitutive expression of several HXT genes, causes constitutive proteolysis of maltose permease, that is, in the absence of glucose. A model of these glucose sensing/signaling pathways is presented.

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Induction of protein-like molecular architecture by self-assembly processes

Bioorganic & Medicinal Chemistry ◽

10.1016/s0968-0896(98)00216-8 ◽

1999 ◽

Vol 7 (1) ◽

pp. 75-81 ◽

Cited By ~ 18

Author(s):

Gregg B. Fields

Keyword(s):

Self Assembly ◽

Molecular Architecture

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

Sensors ◽

10.3390/s21206820 ◽

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.

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The Rheological and Structural Properties of Fmoc-Peptide-Based Hydrogels: The Effect of Aromatic Molecular Architecture on Self-Assembly and Physical Characteristics

Langmuir ◽

10.1021/la204426q ◽

2012 ◽

Vol 28 (4) ◽

pp. 2015-2022 ◽

Cited By ~ 120

Author(s):

Ron Orbach ◽

Iris Mironi-Harpaz ◽

Lihi Adler-Abramovich ◽

Estelle Mossou ◽

Edward P. Mitchell ◽

...

Keyword(s):

Structural Properties ◽

Self Assembly ◽

Physical Characteristics ◽

Molecular Architecture

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Glucose dynamics during ozone exposure measured using radiotelemetry: Stress drivers and human concordance

10.1101/2021.12.09.471963 ◽

2021 ◽

Author(s):

Andres R Henriquez ◽

Samantha J Snow ◽

John S House ◽

Alison A Motsinger-Reif ◽

Cavin Ward-Caviness ◽

...

Keyword(s):

Real Time ◽

Glucocorticoid Receptors ◽

Stress Hormones ◽

Glucose Monitoring ◽

Air Pollutant ◽

Ozone Exposure ◽

Metabolic Dysfunction ◽

Serum Samples ◽

Glucose Levels ◽

Wistar Kyoto

Background. Stress-related neurobehavioral and metabolic disorders are associated with altered circulating adrenal-derived hormones and hyperglycemia. Temporal assessment of glucose and these hormones is critical for insights on an individuals health. Objectives. Here we use implantable-telemetry in rats to assess real-time changes in circulating glucose during and after exposure to the air pollutant ozone, and link responses to circulating neuroendocrine stress and metabolic hormones. We also proposed to compare rodent glucose and corticosterone (cortisol in humans) responses to humans exposed to ozone. Methods. First, using a cross-over design, we monitored glucose levels during single or repeated ozone exposures (0.0, 0.2, 0.4 and 0.8-ppm) and non-exposure periods in male Wistar-Kyoto-rats implanted with glucose-telemeters. A second cohort of un-implanted rats was exposed to ozone (0.0, 0.4 or 0.8-ppm) for 30-min, 1-hour, 2-hour, or 4-hour with hormones measured immediately after exposure. Then we assessed glucose metabolism in sham and adrenalectomized rats with or without pharmacological interventions of adrenergic and glucocorticoid receptors. Finally, we assessed glucose and cortisol in serum samples form a clinical study involving exposure of human volunteers to air or 0.3 ppm ozone. Results. Ozone (0.8-ppm) caused hyperglycemia and hypothermia beginning 90-min into exposure, with reversal of effects 4-6 hours post-exposure. Glucose monitoring during four daily 4-hour ozone exposures revealed duration of hyperglycemia, adaptation, and diurnal variations. Ozone-induced hyperglycemia was preceded by increased adrenocorticotropic hormone, corticosterone, and epinephrine, but depletion of thyroid-stimulating, prolactin, and luteinizing hormones. Hyperglycemia was inhibited in rats that are adrenalectomized and/or treated with glucocorticoid inhibitor. There was coherence among rats and humans in ozone-induced corticosterone/cortisol increases. Discussion. We demonstrate for the first time the temporality of neuroendocrine-stress-mediated biological sequalae responsible for ozone-induced metabolic dysfunction as exposure occurs. Real-time glucose monitoring with stress hormones assessment may be useful in identifying interactions among pollutants and stress-related illnesses.

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