Abstract
High levels of blood glucose are always associated with numerous complications including cholesterol abnormalities. Therefore, it is important to simultaneously monitor blood glucose and cholesterol levels in patients with diabetes during the management of chronic diseases. In this study, a glucose dehydrogenase from Aspergillus oryzae TI and a cholesterol oxidase from Chromobacterium sp. DS-1 were displayed on the surface of Saccharomyces cerevisiae, respectively, using the yeast surface display system at a high copy number. In addition, two whole-cell biosensors were constructed through the immobilization of the above yeast cells on electrodes, for electrochemical detection of glucose and cholesterol. The assay time was 8.5 s for the glucose biosensors and 30 s for the cholesterol biosensors. Under optimal conditions, the cholesterol biosensor exhibited a linear range from 2 to 6 mmol·L−1. The glucose biosensor responded efficiently to the presence of glucose at a concentration range of 20–600 mg·dL−1 (1.4–33.3 mmol·L−1) and showed excellent anti-xylose interference properties. Both biosensors exhibited good performance at room temperature and remained stable over a three-week storage period.
Highlights
Diabetes is currently a global epidemic with over 400 million cases and the prevalence of which is rapidly increasing [1,2]
Previous reports suggested that the glucose dehydrogenase derived from Aspergillus oryzae TI is a flavin adenine dinucleotide (FAD)-dependent oxidoreductase, which has the characteristics of high substrate specificity against glucose, excellent thermal stability and is not affected by dissolved oxygen [29]
The G1 strain was cultured in a 2% glucose medium to the mid-logarithmic growth phase, and was transferred to a 2% galactose medium to induce the persistent expression of Gdh1
Summary
Diabetes is currently a global epidemic with over 400 million cases and the prevalence of which is rapidly increasing [1,2]. The disease is associated with numerous complications, especially cardiovascular diseases. Effective monitoring of blood glucose and cholesterol plays a crucial role in the management of diabetes. Large biochemical analyzers are the mainstream methods of detecting diabetes related blood parameters in clinical practice [6,7,8]. The approach requires specialized instruments and complicated experimental procedures [9] it is highly reliable and gives high precision. The optical and electrochemical based POCT biosensors gradually become the leader choices [11]. Electrochemical biosensors are more favorable in practical applications [13].
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