Array based design of multi-wavelength fluorescence system

Estes, C.; Powers, Linda S.

doi:10.1109/iembs.2001.1017474

Cited by 3 publications

(1 citation statement)

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“…Conventional optical elements, like lenses and fiber optics, exhibit a low-level fluorescence in the blue region on excitation in the UV region. We have therefore used reflective optics to provide hemispherical collection of the fluorescence [7], [9]- [11], [18]. However, fluorescent photons are lost in reflection, and it is important to minimize the number of reflections required to collect these photons.…”

Section: Detection Technologymentioning

confidence: 99%

Is what you eat and drink safe? detection and identification of microbial contamination in foods and water

Lloyd¹,

Cleary

Kim

et al. 2003

Proc. IEEE

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Current technologies for assessing the microbial load in food and water require cellular outgrowth to increase the cell count to a detectable level. This step therefore makes real-time assessment of microbial loads impossible. To circumvent this problem, we have developed a high-sensitivity, multiwavelength fluorescence detector and signal-collection and processing software. This detection system enables one to distinguish between abiotic matter, sporulated bacteria, vegetative bacteria, dead bacteria, and other biomaterials containing aromatic amino acids. Our detection limit is in the 10-100 cell/cm 2 range (or per cm 3 if bulk aqueous samples are used), and there is no sample contact. To supplement this detection system, we have developed a variety of ligands, including hemin derivatives, peptides, glycoconjugates, and siderophores, for cell capture to circumvent problems associated with antibodies. These materials are tethered to disposable surfaces (glass, plastics) in arrays for use in capturing biomaterials (e.g., live bacterial cells, dead cells, spores, and toxins); identification is based on which sector of an array it binds to. The detection system can serve as a reader for these coated materials, and variants have been tested for use in scanning food surfaces and food wash water.

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Section: Detection Technologymentioning

confidence: 99%

Is what you eat and drink safe? detection and identification of microbial contamination in foods and water

Lloyd¹,

Cleary

Kim

et al. 2003

Proc. IEEE

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In SituMicrobial Detection in Mojave Desert Soil Using Native Fluorescence

Smith

Duncan²,

Neary³

et al. 2012

Astrobiology

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We report on the use of a portable instrument for microbial detection in the Mojave Desert soil and the potential for its use on Mars. The instrument is based on native fluorescence and employs four excitation wavelengths combined with four emission wavelengths. A soil dilution series in which known numbers of Bacillus subtilis spores were added to soil was used to determine the sensitivity of the instrument. We found that the fluorescence of the biological and organic components of the desert soil samples studied can be as strong as the fluorescence of the mineral component of these soils. Using the calibration derived from B. subtilis spores, we estimated that microbial content at our primary sampling site was 10(7) bacteria per gram of soil, a level confirmed by phospholipid fatty acid analysis. At a nearby site, but in a slightly different geological setting, we tested the instrument's ability to map out microbial concentrations in situ. Over a ∼50 m diameter circle, soil microbial concentrations determined with the B. subtilis calibration indicate that the concentrations of microorganisms detected varies from 10(4) to 10(7) cells per gram of soil. We conclude that fluorescence is a promising method for detecting soil microbes in noncontact applications in extreme environments on Earth and may have applications on future missions to Mars.

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