Browsing by Author "Yakymyshyn, Chris"

Now showing 1 - 2 of 2

Fiber-optic microsensors to measure backscattered light intensity in biofilms
(2000-07) Beyenal, Haluk; Lewandowski, Zbigniew; Yakymyshyn, Chris; Lemley, B.; Wehri, J.
We have constructed tapered fiber-optic microsensors with a tip diameter of less than 10 um to measure profiles of backscattered light in biofilms, which are thin layers of micro-organisms firmly attached to surfaces. The observed response agrees well with local effective diffusivity microelectrode measurements, with R2 > 0.85. A strong relation between signal intensity and wavelength has been observed at 670 and 1320 nm. These sensors have the potential to replace local effective diffusivity microelectrodes for true in situ biofilm measurements.
An optical microsensor to measure fluorescent light intensity in biofilms
(2004-09) Beyenal, Haluk; Yakymyshyn, Chris; Hyungnak, Jeon; Davis, Catherine C.; Lewandowski, Zbigniew
We have developed an optical microsensor to quantify fluorescent light intensity distribution in biofilms. The optical system consisted of a beam splitter, light couplers, filters and a spectrophotometer able to accept the fiberoptic cable to measure fluorescent light intensity. The emitted light, fluorescence from the biofilm, was collected at the tip of the optical microsensor and was transferred to a spectrophotometer via a fiberoptic cable. The total fluorescent light intensity was evaluated from the emission spectrum by numerical integration. The newly developed fiberoptic microsensor was tested using a Staphylococcus aureus strain producing yellow fluorescent protein (YFP) grown as biofilm. We used a 405-nm violet laser diode for excitation, and measured the emission intensity between 480 nm and 540 nm. The optical microsensor that quantifies fluorescent light intensity is a promising tool in biofilm research which often requires detection and quantification of fluorescent light intensity distribution generated by various fluorescent proteins.