An immunological approach to the analysis of art materials: The effect of aging and pigment interaction on antigenic detection of proteinaceous paint binding media using an improved protocol for enzyme-linked immunosorbent assays.

摘要

Molecular identification of materials used in art making provide valuable information about the artwork and how best to preserve it. Presently, analytical methods capable of detecting proteinaceous materials in art and artifacts are instrument intensive and limited in their ability to identify specific proteins, especially when they occur in mixtures. Immunological methods of analysis hold great potential for applications within art conservation. In particular, the method of enzyme-linked immunosorbent assay (ELISA) has begun to emerge as a valuable complement, or in some instances an alternative, to well established analytical methods such as FTIR and GC/MS. Until recently, the reliability of ELISA to detect target molecules as they exist in art materials and the effects that aging and pigment interaction have on the molecule's antigenic properties have received little attention. This study evaluates the ability of several antibodies to detect proteinaceous materials in art and cultural property, specifically the avian egg protein ovalbumin, collagen, and casein from a range of species, natural gum glycoproteins such as gum arabic, gum tragacanth, ghatti gum, as well as mixtures of each. Extensive investigations using reference samples of traditional paint formulations evaluate the impact of accelerated aging to each protein's antigenic detection. In addition, a comparison is made of the potential inhibitory effects of 21 different pigments on protein detection. The present study also offers an improved ELISA protocol that integrates a signal amplification step involving biotinylated secondary antibodies and streptavidin alkaline phosphatase, a technique previously unused in the field.;Results from assays of paint samples indicate that ELISA is indeed a robust and highly sensitive method for analysis of pigmented art materials. Despite findings that indicate aging, in particular photo-degradation, decreases detection sensitivity, the technique still exhibits extremely sensitive detection limits for aged paint samples ranging from less than 1 ng to 2 mug of paint depending on the type of protein/pigment combination analyzed.