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Pliny the Elder (AD 23 - August 25, 79)
Pliny observed that "...sea water is made smooth by oil, and so divers sprinkle oil on their face because it calms the rough element..."
The ideology that oil calmed troubled waters was created by Pliny the Elder and carried on for centuries after his death in August 25, 79. -
Benjamin Franklin (January 17, 1706 -April 17, 1790)
Likely the first to study this phenomenon scientifically was one not normally associated with the biology of membranes
He added a small amount of oil to the water in a small pond in Clapham Common
Immediately he noticed that the oil spread in a thin film over the surface of the water until a large portion of the pond was "smooth as a looking glass" -
John Rayleigh (12 November 1842 – 30 June 1919)
Continued the ideology of Benjamin Franklin.
Lord Raleigh conducted a series of quantitative experiments with oil and water. He was able to carefully measure the area to which a known volume of oil would expand and also calculated the thickness of the oil film. -
Agnes Pockels (1862-1935)
She describes some experiments that she had conducted in her kitchen. Agnes Pockels had developed on her own with little training and support from others in the scientific establishment, a device for carefully measuring the exact area of an oil film.
Lord Rayleigh helped her publish her first set of results -
Charles Ernest Overton (1865–1933)
He found that the ability of a substance to pass through the membrane was related to its chemical nature. Nonpolar substances, Overton discovered, would pass quickly through the membrane into the cell.
Overton published a preliminary hypothesis in which he proposed: (1) that there are some similarities between cell membranes and lipids such as olive oil, and (2) that certain molecules (i.e., lipids) pass through the membrane by "dissolving" in the lipid interior of the membrane. -
Irving Langmuir (1888-1957)
A chemist and physicist.
He published a paper on the chemistry of oil films
His research turned to lipids and the interaction of oil films with water. Using an improved version of the apparatus originally developed by Agnes Pockels (Langmuir trough), he was able to make careful measurements of surface areas occupied by known quantities of oil.
He proposed that the fatty acid molecules form a monolayer by orienting themselves vertically with the hydrocarbon chains away from the water and the car -
Period: to
Fluid Mosaic Model evolutions based on interpretations of data
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Gorter and Grendel
Found that lipid molecules can form bilayers, and that the surface area of the monolayer extracted from the cells is approximately equal to twice the surface area of the cells
cCncluded that red blood cells are covered by a layer of fatty substances that is two molecules thick -
J. D. Robertson
Proposed a modified version of the membrane model, based primarily on electron microscope studies, which he called the "unit membrane"
According to the unit membrane model, the two outer, darker lines are the protein layers and the inner region the lipid bilayer. -
Singer and Nicolson
The unit membrane model was eventually replaced in the early 1970s by the current model of the membrane (the fluid mosaic model).
It retained the basic lipid bilayer structure proposed by Gorter and Grendel and modified by Danielli and Davson and Robertson. The proteins, however, are thought to be globular and to float within the lipid bilayer rather than form the layers of the sandwich-type model. -
Danielli and Davson
The model proposed by Danielli and Davson was a "sandwich" of lipids (arranged in a bilayer) covered on both sides with proteins -
Unwin and Henderson
They found that the portion of the protein that spans the lipid bilayer is hydrophobic in nature (i.e., similar to the lipids forming the bilayer) and arranged in a three-dimensional shape, often in the form of an alpha helix
