Sampling Techniques and Genomic Analysis of Biological Material from Artworks

The genomic analysis of biological material obtained from artwork or cultural heritage artifacts can be used to guide curation, preservation and restoration. However, the recovery of biological samples from artworks is dependent on the sampling technique used and the media from which the biological materials are recovered. The ideal sampling method should be non-invasive, yet robust. Only rare examples of direct comparisons among sampling techniques have been reported. To develop a framework for the recovery of biological samples for subsequent microbial DNA analysis, we studied five artworks on paper and compared three sampling methods, each with increasing degrees of invasiveness. Minimally invasive swabbing techniques collect samples from the surface, whereas more aggressive techniques such as wet vacuuming were expected to yield more biological material from within the support media. We report a comparison of collection techniques to generate microbial DNA sequence data from artworks on paper. We observed that wet vacuuming resulted in higher DNA recovery than double swabbing and core punches; however, all three techniques yielded satisfactory microbial DNA sequences. Diverse microbial populations existed to varying degrees on the corners and centers of the five artworks studied, but the distribution of the total biomass was relatively even across the surfaces of the works sampled. Studies of peripheral regions, where sampling is less likely to cause alterations to the artwork, could thus yield useful results in microbiome studies. These results provide a framework for sampling artworks on paper to obtain biological material for microbial genomic analysis. The methods described may provide microbiome identification to facilitate restoration and preservation, and might also contribute to the determination of provenance.