A portable device for on site detection of chicken ovalbumin in artworks by chemiluminescent immunochemical contact imaging

The development of user-friendly devices for on site analysis and characterization of painting materials is one of the most challenging objectives in the diagnostics for cultural heritage. Thanks to the specificity of antigen-antibody reactions, immunological methods have been already successfully applied for the detection of proteins and for their localization within painting stratigraphies. Moreover, by combining the advantages of the immunological techniques with the high detectability offered by chemiluminescence detection, it has been possible to achieve good analytical performance and very low detection limits. This work was aimed at developing a portable analytical device for the detection of chicken ovalbumin (a protein found in egg tempera and in egg-based protective varnishes) in painting samples employing ready-to-use analytical cartridges and a thermoelectrically-cooled CCD camera as a chemiluminescence detector. The protein was extracted from using a simple procedure and revealed by a non-competitive immunoassay with chemiluminescence contact imaging detection. The assay was simple, fast and suitable for the detection of ovalbumin in small samples. This analytical system provided positive identification of ovalbumin in samples obtained from both fresh or artificially aged paint reconstructions and historical paintings. It might be easily employed in different contexts (such as small museums, restoration laboratories or even on site) by restorers to obtain prompt information during restoration actions, such as cleaning operations. In perspective this device could be also employed for the detection of other proteinaceous and organic painting components.