Identification of collagen-based materials in cultural heritage

Abstract

All stakeholders in cultural heritage share an interest in fabrication methods and material technology. Until now methods for analysis of organic materials, particularly proteins, have not been widely available to researchers at cultural institutions. This paper will describe an analytical method for the identification of collagen-based materials from soft tissue sources and show examples of its application to diverse museum objects. The method, peptide mass fingerprinting (PMF), uses enzymatic digestion of extracted proteins to produce a mixture of peptides. The mass spectrum of the mixture contains characteristic marker ions-a peptide mass fingerprint-which are compared to species-specific markers from references as the basis of identification. Preliminary results indicate that analysis of materials from aged samples, several different tissue types, and tanned or untanned materials yields comparable PMF results. Significantly, PMF is simple, rapid, sensitive and specific, has been implemented in a museum laboratory, and is being practiced successfully by non-specialists.

Using ZooMS to identify fragmentary bone from the Late Middle/Early Upper Palaeolithic sequence of Les Cottés, France

“…MALDI-TOF-MS replicates (n ¼ 3; mass range 900e4000) were averaged for each sample and manually inspected for the presence of relevant peptide markers (A-G) in mMass v. 5.5.0 (Strohalm et al, 2010). Naming of peptide markers follows Kirby et al (2013). Peptide markers P1 and P2 are recent additions to the original scheme, and selected to separate Cetacea and Pinnipeds (Buckley et al, 2014).…”

“…Spectra were compared with peptide marker series (A-G) for all available vertebrate species (Buckley et al, 2009(Buckley et al, , 2014Kirby et al, 2013). Marker series are similar for some closely related species.…”

Animal origin of 13th-century uterine vellum revealed using noninvasive peptide fingerprinting

“…A notable proponent of follicle pattern analysis was Ryder (10), who used the technique to identify animal species; however, not all parchments had discernible follicle patterns, not every pattern could be identified, and paleographers have often been overconfident in their ability to discern species origin from such patterns. Protein (11,12) and DNA-based methods (13)(14)(15)(16)(17) potentially offer absolute determination of species but, until now, have had other limitations. Toniolo et al (11) analyzed 5 mg of parchment from the 13th-century "Marco Polo Bible" at the Biblioteca Medicea Laurenziana, and used peptide sequences to identify a single leaf as calfskin, although if more leaves had been analyzed the results may have revealed different species as was the case with the family's archival documents (Table S1).…”

“…To assess the quality of our results, we performed a comparative analysis of the same sample using conventional ZooMS techniques that require destructive sampling (12), as well as nondestructive electrostatic ZooMS (eZooMS). For the purpose of this experiment, we used two different documents: (i) a 16th-century manorial court roll (Fig .…”

Earliest Evidence for the Ivory Trade in Southern Africa: Isotopic and ZooMS Analysis of Seventh–Tenth Century ad Ivory from KwaZulu-Natal

“…Very small amounts of collagen are extracted, converted to gelatin and the gelatin enzymatically fragmented into small peptides. The masses of these peptides are determined by time-of-flight mass spectrometry and compared with known reference sequences (Buckley et al 2009(Buckley et al , 2010Buckley and Collins 2011;Kirby et al 2013;von Holstein et al 2014). Collagen is more robust than DNA, and ZooMS requires smaller samples than equivalent DNA sequencing analysis, so it was the preferred method here.…”