Identification of proteins in painting cross-sections by immunofluorescence microscopy

Abstract

Immunofluorescence microscopy offers a highly specific analytical tool for unambiguous recognition and mapping of proteins in complex matrices. In the present work, the analytical potentials of immunofluorescence microscopy have been exploited to provide recognition of proteinaceous binders in painting cross-sections. An optimised analytical protocol is proposed for the identification of ovalbumin and of bovine serum albumin as markers of egg white and casein, respectively. The study has been carried out on laboratory model samples simulating both easel and mural paintings. The obtained results demonstrated the effectiveness of the method, suggesting the potential future use of immunofluorescence microscopy as a routine diagnostic tool in conservation science. Possible developments of the proposed methodology in order to improve the specificity of the method and its detection sensitivity are presented and discussed.

The Biochemistry and Artistic studies: a novel integrated approach to the identification of proteinaceous binders in polychrome artifacts

“…Furthermore, the precise quantification of binders in complex mixtures was rarely achieved. Few innovative techniques (MALDI-TOF-MS, immune-enzymatic assays) were reported lately for identification of natural binders, but further research still has to be done [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45].…”

“…The proteinaceous binders have a similar emission of fluorescence (around 440 nm) therefore their identification through UV fluorescence mapping on the paint surface or in cross-section is not fully and exclusively indicative; in exchange the pigments can give specific fluorescence, the pigment being able to remove the binder's fluorescence [1,19,24,39].…”

“…Immunological techniques have also been investigated, with promising results for the identification of proteinaceous binders in polychrome samples and paint cross-sections, but for the moment their optimization is still far from being fully assessed [39][40][41][42][43][44][45]. Published papers report the use of immunofluorescence techniques to identify the media of XVthXVIIIth century European paintings [43] and artificially aged collagen paints [44].…”

“…Published papers report the use of immunofluorescence techniques to identify the media of XVthXVIIIth century European paintings [43] and artificially aged collagen paints [44]. A recent paper proposes an optimized analytical protocol using Immuno-Fluorescence Microscopy (IFM) for the identification of markers of egg white and casein, respectively [39]. The radio-immunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA) have been proposed as alternative methods [39,40,42,45].…”

“…A recent paper proposes an optimized analytical protocol using Immuno-Fluorescence Microscopy (IFM) for the identification of markers of egg white and casein, respectively [39]. The radio-immunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA) have been proposed as alternative methods [39,40,42,45]. An ELISA protocol was developed at the Getty Conservation Institute for quick and simultaneous identification of glues, casein, plant gums etc.…”