Biomedical subjects

C R Suri

Publications and source records attributed to C R Suri.

4 recordsLinked to original sources

PubMed2004

Isolation of a member of Acinetobacter species involved in atrazine degradation.

Contribution of Acinetobacter genus in the degradation of atrazine and its analogs is reported here. An interesting bacterial isolate capable of degrading atrazine as high as 250 ppm was isolated from a soil heavily contaminated with atrazine. The permissible level of atrazine in drinking water is 3 ppb and hence use of a strain capable of atrazine degradation as high as 250 ppm would be of immense help for rapid environmental cleanup. This isolate was found to be capable of best growth at 37 degrees C and at pH inclined towards the alkaline side. It was found that atrazine was utilized as a carbon and not as a nitrogen source. Acinetobacter species was also active on other triazine pesticides, viz., simazine, terbutryn, cyanazine, and prometon. There are very few reports on the degradation of atrazine by any member of this genus and hence this could lead to new degradation pathways and new metabolites.

Acinetobacter↗

PubMed1996

Activating piezoelectric crystal surface by silanization for microgravimetric immunobiosensor application.

The development of a microgravimetric immunobiosensor using a piezoelectric quartz crystal as a detector requires a stable and reproducible immobilization method for ligand binding. The method of silanization using 3-aminopropyltriethoxysilane (APTES) has been widely used for activating the carrier surface. In the present study, APTES deposition on a piezoelectric crystal surface was studied under various solvent conditions. A fluorescence method, using fluorescence isothiocyanate as a dye, was demonstrated for the quantification of amino groups on the silanized piezoelectric crystal surface. The optimum binding conditions of APTES deposition on a piezoelectric crystal surface were incorporated for the covalent immobilization of protein on the crystal surface in developing a stable and sensitive microgravimetric immunobiosensor. Determination of immunoglobulin G (IgG) concentration was performed using APTES modified piezoelectric crystals coated with protein G. The resonant frequency shift, resulting from the formation of protein G-IgG complex on the crystal surface, correlated with the concentration of IgG in the range 10 ng/ml to 0.1 mg/ml. The APTES modified, protein G coated crystal were found to be quite stable and did not show a significant loss of sensitivity even after 12 weeks of storage at 4 degrees C in a desiccator.

Biosensing Techniques↗

PubMed1995

Development of piezoelectric crystal based microgravimetric immunoassay for determination of insulin concentration.

A microgravimetric, piezoelectric crystal based immunoassay for the quantification of insulin concentration is described. The method utilizes a modified piezoelectric crystal device having an antibody specific to insulin bound to its surface. The antibody to insulin was immobilized on the surface of crystal electrode by using either 3-aminopropyltriethoxy silane (3-APTES), polyethyleneimine (PEI) or covalently coupled protein A-gold immobilization method. Coating an electrode with a cross linked protein A-antibody complex gave better results in terms of sensitivity and stability. Using the system described, the insulin concentration up to 1 ng ml-1 could be detected. The stability and reusability of the system was further improved by using a mild eluting reagent which successfully removed the bound insulin molecules from the antibody-coated crystal without affecting the immobilized insulin antibody. Scanning tunneling microscopic (STM) study was also done to confirm the surface coverage and orientation of insulin and antibody molecules on the modified piezoelectric crystal electrode surface. A comparison between the present study and the well-established radioimmunoassay technique (RIA) revealed that the described microgravimetric immunoassay technique (MIA) could successfully be developed as an alternative of RIA.

Biosensing Techniques↗

PubMed1994

Determination of immunoglobulin M concentration by piezoelectric crystal immunobiosensor coated with protamine.

In the present study, the specific binding between protamine and immunoglobulin M (IgM) has been exploited to construct a piezoelectric crystal based immunobiosensor for the determination of concentration of IgM. The system consisted of highly stable IC based oscillator, 8-digit frequency counter and modified piezoelectric crystal device. The crystal surface was physically modified and chemically treated (refluxed) with strong acid to produce stable hydroxylic groups of silicon oxide. This modified surface reacted strongly with coupling reagents for binding of protein molecules. The protamine was immobilized by using either gamma-aminopropyltriethoxy silane (gamma-APTES) or 2.2.2-trifluoroethanesulfonyl chloride (tresyl chloride). Scanning electron microscope images of piezo crystal revealed that tresyl activated surface presented more surface area for binding than gamma-APTES modified surface and showed better sensitivity. This immobilization technique also improved the reproducibility and long term stability of the detection system. Using the system described, the IgM concentration up to the level of 10 ng/ml could be detected without interference of IgG.

Biosensing Techniques↗