A Dual Electrode Biosensor for Glucose and Lactate Measurement in Normal and Prolonged Obese Mice Using Single Drop of Whole Blood

Abstract

Understanding the levels of glucose (G) and lactate (L) in blood can help us regulate various chronic health conditions such as obesity. In this paper, we introduced an enzyme-based electrochemical biosensor adopting glucose oxidase and lactate oxidase on two working screen-printed carbon electrodes (SPCEs) to sequentially determine glucose and lactate concentrations in a single drop (~30 µL) of whole blood. We developed a diet-induced obesity (DIO) mouse model for 28 weeks and monitored the changes in blood glucose and lactate levels. A linear calibration curve for glucose and lactate concentrations in ranges from 0.5 to 35 mM and 0.5 to 25 mM was obtained with R-values of 0.99 and 0.97, respectively. A drastic increase in blood glucose and a small but significant increase in blood lactate were seen only in prolonged obese cases. The ratio of lactate concentration to glucose concentration (L/G) was calculated as the mouse’s gained weight. The results demonstrated that an L/G value of 0.59 could be used as a criterion to differentiate between normal and obesity conditions. With L/G and weight gain, we constructed a diagnostic plot that could categorize normal and obese health conditions into four different zones. The proposed dual electrode biosensor for glucose and lactate in mouse whole blood showed good stability, selectivity, sensitivity, and efficiency. Thus, we believe that this dual electrode biosensor and the diagnostic plot could be used as a sensitive analytical tool for diagnosing glucose and lactate biomarkers in clinics and for monitoring obesity.

The development of an electropolymerized, molecularly imprinted polymer (MIP) sensor for insulin determination using single-drop analysis

“…[35][36][37]39 Although the latter simplifies on-site analysis, since no electrochemical cell or stirrer is required, there are only a few publications on this subject. 3,34,35,37,[40][41][42][43] But, for example, a smartphone-based cyclic voltammetry (CV) platform was designed as a portable system for single-drop determination of glucose. 44 In another study, a similar smartphonebased sensory system using square-wave voltammetry (SWV) and a graphene SPE was constructed to detect norepinephrine in a sample drop.…”

“…For this purpose, a dual enzyme-based biosensor was prepared using glucose oxidase and lactate oxidase on two working SPCEs. 43 This study aimed to develop the MIP-SPCE sensor to detect insulin in one sample drop (50 µL). Although examples of protocols for the synthesis of MIPs for the electrochemical detection of insulin have been described previously, 2,11,13,24 to the best of our knowledge, this is the first demonstration of an MIP-based sensor for a single-drop analysis of insulin without the use of solid-state synthesis or nanomaterials for signal amplification.…”

Application of NAD+-Dependent Electrochemical Dehydrogenase Biosensors in Human Physiological Fluids: Opportunities and Challenges

“…Inspired by the seminal work of Clark and Lyons, various types of enzymatic electrochemical biosensors have been developed successively for the detection of diverse targets (lactate, ethanol, bile acid, etc. ), which enabled high-throughput and onsite analysis of biological samples [2][3][4]. All such procedures need the addition of sensing elements to the electrode structure through multiple strategies, including physical adsorption, covalent bonding techniques, and mediators [5][6][7].…”

Generalized Analytical Model for Enzymatic BioFET Transistors

“…Enzyme biosensors have significantly developed within the last 20 years [ 1 , 2 , 3 , 4 ], with modern trends indicating a down-scaling in biosensor sizes [ 4 ]. The proposed solution for the next 10 years is the co-integration of the enzyme receptor with Metal Oxide Semiconductor (MOS), or any Field Effect Transistor (FET) as transducer, to produce an ENFET (Enzyme-Field Effect Transistor) [ 5 ].…”