In Situ Quantification of Glucose Concentration in Airway Surface Liquid With Functionalized ZnO Nanorod-Coated Microelectrodes

Abstract

The surface of the airways that conduct gases into and out of the lungs has components that protect the host from inhaled and aspirated pathogens. The thin (4–7 µm height) layer of airway surface liquid (ASL) that lines the airways has physicochemical properties that are important for normal function of these antimicrobial components. Among these properties, low glucose concentration is required for normal antimicrobial activity. Current methods for assessing the ASL have important flaws (temporal resolution, dilution factors, collection volume), which have been a recurring obstacle for understanding diseases in which ASL composition is abnormal. To circumvent these problems, microelectrodes coated with ZnO nanorods and immobilized glucose oxidase was used to determine glucose concentration in ASL of well-differentiated cultures of human airway epithelia. The sensor responded to glucose linearly over a concentration range of 0.128 to 8 mM and the effects of electroactive interferents were minimal. The measured concentration of glucose in ASL was consistent with values previously reported. This method confirms the presence of a transepithelial glucose concentration gradient in human airway epithelia and is an important step towards characterizing the physicochemical properties of ASL and understanding diseases caused by changes in ASL composition.

Recent progress on growth and device development of ZnO and CuO nanostructures and graphenenanosheets

“…It is important to mention that the developed ZnO NRs decorated glass pipette microelectrode used for intracellular detection is in fact suitable for detecting biological processes and can be applied in many biological thin or thick tissues. 83,84 To mention some of such possibility we choose the following two applications. In the first, the intracellular K + in Xenopus laevis oocytes was measured.…”

“…83 The other examples illustrate the efficiency of the developed technique for in situ quantification of glucose concentration in airway surface liquid (ASL) tissues using functionalized ZnO NR-coated microelectrodes. 84 These examples indicate that the developed technique holds promise for many applications in nano-medicine where small sample sizes are to be investigated.…”

A novel fluorescent sensor protein for detecting changes in airway surface liquid glucose concentration

“…Work by others has shown that highly technical glucose sensor technology using ZnO-coated microelectrodes or a phosphorescence sensing material [crystalline iridium(III)-Zn(II) co-ordination polymers], which utilize glucose oxidase production of H 2 O 2 to quantify glucose, can be useful in measuring glucose in small fluid volumes such as ASL and over similar ranges of glucose (0.1–6 mM) [ 26 , 31 , 32 ]. However, the benefit of a fluorescent molecular glucose sensor that is easy to produce and can be used to rapidly measure real-time (and reversible) changes in glucose concentration in ASL overlying cells in situ is particularly attractive.…”

Nanomedical Platform for Drug Delivery

“…Gold nanoparticles have property of converting allowed radiofrequency into high frequency is known as 'Quantum Dot' property and can be used for destroying cancer cells [28,29]. Their combination of low inherent toxicity, high surface area and tunable stability provides them with unique attributes that should enable new delivery strategies [30].…”

“…Nanotechnology as applied to medicine will bring significant advances in diagnosis and treatment of disease. Nanomedicine includes several distinct application areas: Drug delivery, drugs and therapies, in vivo imaging, in vitro diagnostics, biomaterials, and active implants [2,3]. In these fields, Nanomedicine has seen a surge in research activity over the past decade.…”