Aim: We have studied the only found three skin debris (P1, P2 and P3) deposited on the Face area of our sample of the Turin Shroud. Methods: P1, P2 and P3 were explored by optical microscopy, by SEM and by EDX analysis. Results: All P1, P2 and P3 are true skin debris, as observed in optic and electronic microscopy; their elementary compositions show organic matter, plus a sulphur peak that corresponds to keratin. P1, P2 and P3 are constituted of layers of corneocytes; in P3, which is certainly a human skin debris, we can observe both the epidermis and some residual dermis.
The Turin Shroud (TS) is a well-known object in which a body image is imprinted ( Marion & Lucotte, 2006 ). In 1978 and in 1988, Giovanni Riggi di Numana took some samples and dusts ( Riggi di Numana, 1988 ) of the TS, at areas corresponding to Hands, Face (a 1978 sample taken on the Face area was deposited by him on a special sticky-tape), Feet, Buttocks and the 14C area. We had access to this sticky-tape, cutted up in a triangular form, and realised on it preliminary investigations ( Lucotte, 2012 ) concerning mineral particles.
I have recently published three other studies on the triangle: the first one ( Lucotte, 2015a ) concerned linen (and other textile) fibers. The second ( Lucotte, 2015b ) concerned pollens (and spores); and the third ( Lucotte, 2015c ) red blood cells.
Desquamed epithelial cells―named as “skin debris” (SD)―were previously studied by SEM-EDX ( Varetto, 1990 ; DeGaetano et al., 1992 ), specially in a forensic science perspective ( Burnett, 1995 ). In the present study, we describe in details some SD located on the triangle surface.
The material ( Lucotte, 2012 ) is a small (1.36 mm high, 614 μm wide) sticky-tape triangle (
the end of this article) at the surface of which the portions of fibers, pollen grains, red-blood cells and some plaques of organic matter were deposited.
More than 2500 particles, greater than 1 μm = 1 μ, can be observed at the surface of the triangle. All of them were studied by optical microscopy, SEM (Scanning Electronic Microscopy) and EDX (Energy Dispersive X-ray) analysis. For practical reasons, the surface of the triangle was subdivided into 19 sub-samples areas (areas A to S), the area E being subdivided in five sub-areas E.a to E.e), containing almost all the particles observed. The positions of each particle sticking to the triangle surface were located in a double system of coordinates (in 186 adjacent squares of 50 × 50 μ of the total surface).
Cell debris of the samples were observed, without any preparation, on the adherent part of the surface of the triangle. The observations were conducted by SEM, using a Philips XL30 instrument (environmental version); GSE (Gaseous Secondary Electrons) and BSE (Back Scattering Electrons) procedures were used, the last one to detect heavy material. Elemental analyses for each skin debris were realised by X-ray microfluorescence (XRMF), this SEM microscope being equipped with a Bruker AXS energy dispersive X-ray (EDX); the system of analysis is PGT (Spirit Model, of Princeton Gamma Technology).
Our SEM studies were completed by the optical observations of cell debris numbers 1, 2 and 3 (using a photomicroscope Zeiss, model III, 1972) and by their study in cross-polarized light (with the petrographic version of this microscope).
As an example,
cells taken on the face of a 30-years old living man. We see on the SEM photography several large superposed corneous cells. EDX analysis of one of them shows an elementary composition rich in organic matter (carbon, oxygen and nitrogen) and a secondary peak of sulphur (keratin); also in the spectrum are little peaks of chlorine and sodium (ClNa: salt of the sweat) and of calcium (residual minerals deposited on the skin surface).
We have found only three SD on the triangle:
The a37 particle, located in the A area
This particle is the first SD (designated as P1) observed on the surface of the triangle. The SEM photography of
The P1 spectrum shows peaks corresponding to the constitutive elements (carbon, oxygen and sulphur) of the skin and of the sweat (chlorine and sodium). But the major secondary peaks of the spectrum are those of silicium and calcium; magnesium and aluminium (and probably also potassium and iron) are elements associated to silicium, to constitute a clay mineral of the montmorillonite-illite type ( Lucotte, 2012 ).
It seems that there are remarkable similarities (
(because it is now covered by mineral deposits, accumulated since the time), the TS; but further studies on P1 are problematic, because its most important surface part is covered by a thin plastic layer (
The e2 particle, located in the E area (in sub-area E.a)
This particle is the second SD (designated as P2) observed on the triangle. The two SEM photographies of
The P2 surface is also rough. The below photography of
sulphur (keratin); there are some traces of chlorine (and Na). But the calcium peak is very elevated, and the silicium peak is at the same level to that of sulphur. Quantification shows that―among the non-carbon and oxygen elements―the silicate component (silicium, aluminium and magnesium) represents only about 14.2% of the total, while the calcium component is at more than 66%. We conclude that the surface of the P2 skin fragment is mainly covered by a calcium carbonate deposit.
The e6 particle, located also in the Ea sub-area
This particle is the third SD observed on the triangle, and is designated as P3. The SEM photography of
The P3 surface is sleek, with some micro-spines (
The spectrum below the photography of
Both versions (in GSE and BSE) of the whole P3 particle are shown on
Elementary analysis were realised both for a covered and an uncovered P3 surfaces (spectrums at the black points a and b on the photography of
But the spectrum corresponding to the black point b (the most intensively covered surface portion) is distinct,
for the little peaks upper spectrum of
The SEM photograph of
Study of the P1, P2 and P3 particles by optical microscopy
The location of the P2 particle of the photography of
tography (that of the upper
We have found three skin debris (SD)―designated as P1, P2 and P3―at the surface of a sticky-tape triangle sampled on the Face of the Turin Shroud (TS). These SD are similar, both in ultrastructure and elementary composition, to that of one SD sampled on the face of a living man. Structurally these three SD, that have some thickness, are constituted of several layers (illustrated in Prost-Squarcioni et al., 2005 ) and they look like desquamed skin fragments. The rough surface of P1 is similar to that of jointed corneocytes (stratum corneum) of the epiderm superficial part; the finely spinned surface of P3 is similar to that of jointed keratinocytes (stratum spinosum) of the epiderm lower part ( Breathnach, 1975 ). Chemically they are rich in organic matter, with a marked peak of sulphur that corresponds to keratin; the P2 surface is completely covered by calcium carbonate, that hitchs to see its surface ultrastucture.
A possibility remains that the three skin debris observed could be those of rabbit skin, a sort of glue commonly used in the painting process in some portraits.
Skin debris | Skin elements | Mineral overload | Mineral and metallic particles at the surface | ||||
---|---|---|---|---|---|---|---|
Numbers | Organic matter | Sulphur | Chlorine | Sodium | Clays | Calcium carbonate | |
P1 | + | + | + | + | +++ | + | No |
P2 | + | + | + | ? | ++ | +++ | No |
P3 | + | + | + | + | + | + | Yes |
Footnote: + : moderate level; ++: consistant level; +++: elevated level.
means that both epiderm and derm layers are present). Some packs of collagen micro-filaments (not found on the triangle surface) surround the rabbit skin debris (
Proof of the human nature of the P3 skin debris is given by the observation of the two red blood cells groups neighbouring this SD : the h1 (e5 particle) group―the hematy group h16-18 ( Lucotte, 2015c )―and the h2 (e22 particle) group―the hematy group 19-20 ( Lucotte, 2015c )―shown in
The P1 skin debris is probably a human corneous fragment exfoliated from a finger top (where epiderm is thicker). The important calcium carbonate deposit that covers the whole P2 skin debris renders it unsuitable for further analysis.
Corneocytes are death-cells, without nucleus and DNA. Skin debris P3, composed of epiderm and derm layers attached, provide us an unique material to study by molecular genetics techniques the genomic components of the corresponding individual. Our current study on P3 concerns genomic DNA extractions from this peculiar skin debris.
We have found three skin debris (P1, P2 and P3) on the surface of a sticky-tape joined to the Face area of the
Layers | Aspects | Cells |
---|---|---|
Stratum corneum | Cornified | Corneocytes |
Stratum lucidum | White | White corneocytes |
Stratum granulosum | Granular | Flated keratinocytes, with grains |
Stratum spinosum | Spinous | Polygonal keratinocytes, with spines |
Stratum germinativum | Basal | Cylindric cells |
Turin Shroud. The largest one, P3, is the only one that comprises both epiderm and some part of derm layers. So, it is an excellent target tissue candidate to explore the DNA of the individual who exfoliated his skin debris on the Shroud.
We thank T. Derouin (Phanerogamy Department of the Natural History Museum of Paris) for allowing us to use his photomicroscope, and T. Thomasset (Analysis of a Physico-Chemistry Service of the UTC of Compiègne) for his precious help in SEM-EDX analysis.
Gérard Lucotte, (2016) Skin Debris on the Face of the Turin Shroud: A SEM-EDX Analysis. Archaeological Discovery,04,103-117. doi: 10.4236/ad.2016.42008