Re: [DIYbio] Methodology help needed - how to measure nail light absorbance

Ok lets start again.

On Wed, Nov 21, 2012 at 10:52 AM, wolass <wolass@gmail.com> wrote:
> Hey guys
>
> I would like to measure what wavelengths are absorbed by the human nail
> plate.
>
You want to find the absorbance of the nail as it is presented on the
finger. Otherwise you could just measure or find the absorbance of
keratin. I am not sure

> My only idea so far is to take the nail clippings, dissolve them in KOH and
> than pour this liquid sample into a spetrophotometer.
>

Most people have said this won't work since you're changing the
structure and affecting absorbance.

> Do you see other options?
>
> I will be grateful for your help

Here are some links for you and others on the list to help find a solution:

[1] AA composition of human nail as measured by gas-liquid
chromatography (It shows how they collected the sample, nothing else
is probably relevant for your work)
http://www.clinchem.org/content/22/10/1608.full.pdf

[2] A chapter about the set-up of the nail bed and its components, if
anyone is interested:
http://ir.inflibnet.ac.in:8080/bitstream/10603/2434/9/09_chapter%201.pdf

[3] Percutaneous absorption test – A case of effectiveness evaluation
of skin-whitening cosmetics (Measuring affects of skin whitening
products; maybe applicable to nails?)
http://altweb.jhsph.edu/wc6/paper407.pdf

[4] "The Nail Plate's Lack Of Absorptive Capability"
According to "Nails - Review of Structure, Function and Strategies to
Treat Disorders," published by Linda D. Rhein, Ph.D., the nail plate
has little absorptive capability because of its high disulfide bond
content and its relatively low lipid and lipid bi-layer content.
Disulfide bonds create a tight structure, which is almost impermeable
to topical therapeutic agents. Also, the disulfide bonds shield the
hydrogen bonds from chemicals like urea, included in some topical
treatments, which could disrupt H-bonding and make penetration easier.
The lack of lipid elements in the nail plate impedes the penetration
of lipid-based therapeutic agents.
http://www.viviforyou.com/vivinal/absorption.html

[5] The effect of nail polish on pulse oximetry. (not sure how useful for you)
http://www.anesthesia-analgesia.org/content/67/7/683.long

Regarding article [5], can you modify oximeters for your purposes?

Good luck

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