A Bacillus sphaericus Based Biosensor for Monitoring Nickel Ions in Industrial Effluents and Foods

A microbial-based biosensor has been developed based on enzyme inhibition bioassay for monitoring the presence of Ni(II) in real-time samples. The sensing element is immobilized Bacillus sphaericus MTCC 5100 yielding urease enzyme. The transducer is an NH 4 + ion selective electrode in conjunction with a potentiometer. Heavy metals are potentially toxic to human beings. Nickel is associated with causing adverse health effects such as dermatitis and vertigo, in humans. Toxicity is manifested by affecting T-cell system and suppressing the activity of natural killer cells. Nickel finds applications in electroplating, coinage, electrodes, jewellery, alloys. The foods rich in Ni(II) are nuts, beans, oats, and wheat. The range of Ni(II) detection by the developed biosensor is 0.03–0.68 nM (0.002–0.04 ppb) with a response time of 1.5 minutes. For application, the Ni(II) effluent was procured from an electroplating industrial unit and was found to have a concentration of 100.0 ppm Ni(II). In foods, wheat flour sample was acid digested and Ni(II) was specifically complexed in the presence of other cations, and had an Ni(II) concentration of 0.044 ppm. The developed system has a reliability of 91.5% and 90.6%, respectively, for the samples and could possibly replace the existing conventional techniques of analysis

L-arginine biosensors: A comprehensive review

Arginine has been considered as the most potent nutraceutics discovered ever, due to its powerful healing property, and it's been known to scientists as the Miracle Molecule. Arginine detection in fermented food products is necessary because, high level of arginine in foods forms ethyl carbamate (EC) during the fermentation process. Therefore, L-arginine detection in fermented food products is very important as a control measure for quality of fermented foods, food supplements and beverages including wine. In clinical analysis arginine detection is important due to their enormous inherent versatility in various metabolic pathways, topmost in the synthesis of Nitric oxide (NO) and tumor growth. A number of methods are being used for arginine detection, but biosensors technique holds prime position due to rapid response, high sensitivity and high specificity. However, there are many problems still to be addressed, including selectivity, real time analysis and interference of urea presence in the sample. In the present review we aim to emphasize the significant role of arginine in human physiology and foods. A small attempt has been made to discuss the various techniques used for development of arginine biosensor and how these techniques affect their performance. The choice of transducers for arginine biosensor ranges from optical, pH sensing, ammonia gas sensing, ammonium ion-selective, conductometric and amperometric electrodes because ammonia is formed as a final product

Urea biosensors

A biosensor is an analytical tool that comprises two essential components-an immobilized biocomponent, in intimate contact with a transducer that converts a biological signal into a measurable electrical signal. This review summarizes the studies carried on the development of biosensors for the analysis of urea in different fields of application, the various techniques of immobilization of urease enzyme, the stability and response time characteristics and the transducers used for biosensor development such as pH electrodes, ammonia gas sensing electrodes, ammonium ion-selective electrodes, optical, conductometric and amperometric transducers. Underlying the importance of this study is the fact that urea is toxic above certain concentrations and its continuous real time monitoring in clinical, environmental and food related environments is of utmost interest. The conventional analytical techniques used, although precise, are time consuming and mostly laboratory bound whereas biosensors have the advantages of ease of use, portability and the ability to furnish real time signals

Are we using Thyroid Function Tests Appropriately?

Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples (87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests. 77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7% in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction and order the appropriate test in a rational and cost effective manner