Clara Granzotto

Palaeoproteomic analysis of binding media and adhesives in ancient Egypt

Clara Cranzotto§; Rebecca Stacey£; Enrico Cappellini§

£ Department of Scientific Research, The British Museum, Great Russell St, London, WC1B 3DG, UK; § Natural History Museum of Denmark - University of Copenhagen, Øster Voldgade 5–7, 1350 Copenhagen, Denmark

Proteins from hide, bones, egg and milk have been mentioned to be used as binding media and adhesives by the ancient Egyptians. A vast artistic production from ancient Egypt is still accessible to us but, due to its extremely fragile nature, a surprisingly limited number of analytical studies have been conducted so far on the organic media it includes. Ancient literature sources provide limited information about the use of proteinaceous materials in ancient Egypt, leaving several questions open, such as: were certain protein-based materials preferred for specific applications? Were the same materials used for different purposes in different periods and geographical areas? How did proteins in paint formulations decay over millennia? Recently, the introduction of high-throughput tandem mass spectrometry (MS)-based protein sequencing allowed confident sequencing of ancient proteins. This new, robust and reliable approach, named palaeoproteomics, can provide very innovative results in the study and preservation of cultural heritage collections.

We investigated micro-samples from different artifacts, such as painted coffins, cartonnage and mural paintings dating 3000 BC – 600 AD, by state-of-the-art high-resolution MS-based proteomic strategies. Results revealed animal glue from Bos species was used as binder in both the preparation and, occasionally, paint layers. The accurate identification, at the species level, of the proteinaceous binder, as well as the characterization of its molecular damage represent a significant step forward in the understanding of the painting materials and techniques used in ancient Egypt. The results of this research demonstrate how palaeoproteomics provides new evidence to advance understanding of the use of specific protein sources in art history, with potentially strong implications for future conservation treatments.