Bücher von Bansi D Malhotra

A biosensor is an integrated bioanalytical device that employs biological elements, as analyte sensor, coupled to a transducer for signal detection. Biosensor provides sensitive and selective determination of various compounds of analytical relevance. Recently, use of self-assembled monolayer (SAM) is gaining attention as biosensor matrix. SAM provides a simple route to functionalize electrode surfaces for biosensor fabrication. The alarming rise in the rates of heart diseases due to abnormal levels of cholesterol in blood has stimulated public concern about the estimation of cholesterol level in desired sample. The present book highlights the preparation, characterization and application of some SAMs for immobilization of cholesterol oxidase, cholesterol esterase & horseradish peroxidase for development of cholesterol biosensor. The fabricated bioelectrodes were tested for various parameters like pH, temperature, interferents etc. and have been utilized for free and total cholesterol estimation in solution & serum samples. The results indicate that the SAMs are likely to provide useful matrices for the fabrication of commercial cholesterol sensing bioelectrodes.

Nucleic acid biosensors have been found to have interesting possibilities for applications in various fields including environmental and medical screening. The two types of analysis used for the nucleic acid biosensors are : (a) detection of genotoxicants/ DNA damage (b) detection of DNA hybridization. For the detection of genotoxicants, the double stranded calf thymus DNA has been electrochemically entrapped into conducting polymers like Polypyrrole (PPy) and Polyaniline (PANI) films to detect chlorpyrifos and malathion. Compared to DNA-PPy, DNA-PANI electrodes have better detection limit for chlorpyrifos and malathion (0.5 ppb and 0.01 ppm, respectively) within 30s, and are stable for about 6 months. The PNA and DNA probes specific to M. tuberculosis have been immobilized onto the PPy and PANI films prepared onto ITO glass for detection of complementary target. The obtained detection limit is about 0.1attomole within 30s and electrodes could detect the genomic DNA of M. tuberculosis in serum samples up to 2.5 pg/¿l within about 60s at 300 C and can be used 8¿9 times.