What is the density of a human skin cell? - (Jul/19/2012 )

Hi

A colleague working in physics posed this question today and left myself and a number of fellow scientists, and his own dermatologist wondering.

"What is the density of a human skin cell?"

Understandably this will change depending on the layers of skin, which part of the body, with age etc but in general I could not locate any definitive answer.

Anyone know the answer? Or even how one would go about determining this?

My colleague looked quite exasperated when we said "google it".

Regards
Chris

Do you mean how many skin cells per unit volume or do you mean mass per unit volume?

When he was asking he mentioned if he had a kg of skin cells, what would the density be, so I presume mass per unit volume.

Kind Regards
Chris

Well, you could take a series of samples of human skin (a few hundred thousand cells per sample) and put one sample into each of a series of aqueous solutions that have their densities increased over the series.

Humans are near enough neutrally buoyant so the density of each sample is going to be near 1gcm^-3 but it’s unlikely to be exactly that. Do this over a series of samples from different individuals to obtain a value for a mean human (or mean of the sub-set of humans you have selected by gender, age and race).

Of course I do have to ask where your “friend” is getting 1kg of human skin from. Should we be calling the authorities?

Hi Astilius

I see your point, the closest we got was that skin cells float on water so they must be less dense than water. I will pass on your suggestion, thank you.

I am still surprised that it is not an easily accessible piece of info.

I

Astilius on Thu Jul 19 15:54:16 2012 said:

He mentioned it was for testing the penetrating ability of a laser, but I fear that does little for our case.....makes him sound like bond villain.

Thanks for the info.

Chris

In my experience with cell culture, eukaryotic cells in general are more dense than a normal saline solution or PBS (they sink in these solutions), which means that they will be more dense than water, but how much more is hard to say. According to the wikipedia article(http://en.wikipedia....ical_properties) on adipose tissue, muscle cells have a density of 1.09, so I would expect skin cells to be slightly less dense.

FYI, the near enough neutral density of humans is due to fat deposits in the body (density about 0.9) and the presence of cavities such as the lungs that are full of air and thus more buoyant.

Hi Bob1

Thank you for the information, I passed it on this morning.

In your opinion would pig skin would be quite a close approximation to human skin with regard to density of epithelial layers. It would simplify matters quite a bit if he could use pig skin, but I would be nervous about the scientific merit of this.

Kind Regards
Chris

Absolutely, pigs are a pretty good approximation for most things human. They do tend to have a bit more fat below the skin than humans though.

Thank you for replying

He went to the butchers and seems to be happy with the early results.

Thank you for your help.

Kind Regards
Chris