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bacteria refractive index?
I'm trying to do a project, and long story short, I need to find out the refractive indices of a bunch of bacteria. I've been researching all over the internet and it proving to be really difficult to find many known refractive indices of any bacteria at all.
I specifically am trying to find bacteria with refractive indices ranging from 1.20-1.40. If anybody knows of a good list or is able to find something useful for me that would be great. Thanks.
-Note: I've already done exhausted experiments with E.coli and S.melioti which have just barely the acceptable refractive index, so dont bother with those 2.
2 Answers
- ?Lv 47 years agoFavorite Answer
Experimental values of the extinction of Escherichia coli cells water suspension by Bryant et al. are used for the refractive index determination of these bacteria. The real suspension of E. coli cells is modeled as a system of identical randomly oriented homogeneous circular cylinders. This model permits one to determine the volume average value of the refractive index of the optically soft particles with a narrow size distribution. The discrete Shifrin method is used to calculate the extinction cross section of the finite cylinders. The results indicate that the relative refractive index is practically independent of the wavelength of the incident radiation in the range from 0.4 micrometers to 0.8 micrometers . The mean value of 1.0387 in this range corresponds to the absolute refractive index value equal to 1.384 at 0.589 micrometers . The obtained value of refractive index of E. coli cells is somewhat lower than the result of immersion refractometry measured by Bryant et al.
- DoctorwhoLv 77 years ago
IMO this is a grad-school level question, and it requires the use of a college/university science libraby to research the answer.
I found these:
"... Bacteria have almost the same refractive index as water. This means when you try to view them using a microscope they appear as faint, gray shapes and are difficult to see. Staining
cells makes them easier to see. ..."
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&sou...
"...Most bacteria are colourless. However, their index of refraction is greater than water. ..."
