TY  - CHAP
A1  - Lei, Yu
A1  - Mulchandani, Priti
A1  - Chen, Wilfred
A1  - Mulchandani, Ashok
T1  - Biosensor for direct determination of fenitrothion and EPN using recombinant Pseudomonas putida JS444 with surface expressed organophosphorus hydrolase. 1. modified clark oxygen electrode
N2  - This paper reports a first microbial biosensor for rapid and cost-effective determination of organophosphorus pesticides fenitrothion and EPN. The biosensor consisted of recombinant PNP-degrading/oxidizing bacteria Pseudomonas putida JS444 anchoring and displaying organophosphorus hydrolase (OPH) on its cell surface as biological sensing element and a dissolved oxygen electrode as the transducer. Surfaceexpressed OPH catalyzed the hydrolysis of fenitrothion and EPN to release 3-methyl-4-nitrophenol and p-nitrophenol, respectively, which were oxidized by the enzymatic machinery of Pseudomonas putida JS444 to carbon dioxide while consuming oxygen, which was measured and correlated to the concentration of organophosphates. Under the optimum operating conditions, the biosensor was able to measure as low as 277 ppb of fenitrothion and 1.6 ppm of EPN without interference from phenolic compounds and other commonly used pesticides such as carbamate pesticides, triazine herbicides and organophosphate pesticides without nitrophenyl substituent. The applicability of the biosensor to lake water was also demonstrated.
KW  - Biosensor
KW  - Organophosphorus
KW  - fenitrothion
KW  - EPN
KW  - biosensor
KW  - Pseudomonas putida
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1573
ER  - 
TY  - CHAP
A1  - Rabner, Arthur
A1  - Shacham, Yosi
T1  - A concept for a sensitive micro total analysis system for high throughput fluorescence imaging
N2  - This paper discusses possible methods for on-chip fluorescent imaging for integrated bio-sensors. The integration of optical and electro-optical accessories, according to suggested methods, can improve the performance of fluorescence imaging. It can boost the signal to background ratio by a few orders of magnitudes in comparison to conventional discrete setups. The methods that are present in this paper are oriented towards building reproducible arrays for high-throughput micro total analysis systems (µTAS). The first method relates to side illumination of the fluorescent material placed into microcompartments of the lab-on-chip. Its significance is in high utilization of excitation energy for low concentration of fluorescent material. The utilization of a transparent µLED chip, for the second method, allows the placement of the excitation light sources on the same optical axis with emission detector, such that the excitation and emission rays are directed controversly. The third method presents a spatial filtering of the excitation background.
KW  - Biosensor
KW  - Fluorescence
KW  - imaging
KW  - lab-on-chip
KW  - fluidic
KW  - lenslet array
KW  - LED chip
KW  - image sensor
KW  - biosensor
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1456
ER  -