This paper is a review on the studies performed through imaging and spectroscopy-based analytical methods on ancient 'gilded' art-objects (9th-19th centuries) from the European cultural heritage.The review takes into consideration the gilded surfaces in polychrome art objects (easel and mural paintings, polychrome wooden objects, gilt leather and parchment), thus meaning the materials and techniques of application of gold or its imitations (silver, copper leaves, other metal alloys) from technical, analytical and conservation points of view.The characterization of artistic gilded objects is important for establishing the compositional, structural, morphological and physical-chemical parameters useful for monitoring the conservation state, behavior and evolution in time of their aging/degradation/deterioration processes, the restoration treatments (cleaning, consolidation, retouching, varnishing) influence on the conservation state of the original materials and also for a rationale choice of methods and materials of intervention, compatible with the original ones.The analytical approach has, as main requirement, to be noninvasive and non-or microdestructive, therefore, sampling is to be avoided or reduced to a minimum. A wide range of imaging and spectroscopy-based techniques is nowadays available from optical microscopy, UV fluorescence photography, IR reflectography, X-radiography, thermography, to scanning/transmission/environmental electron microscopy (SEM/TEM, E-SEM), atomic force microscopy (AFM), FTIR and Raman microscopy (micro-FTIR, micro-Raman), X-ray spectrometry (WDXRF/EDXRF/TXRF, XPS), Ion Beam Analyses (PIXE/PIGE, RBS, SR), etc. The most reliable and complete information can be obtained from an integrated, complementary and interdisciplinary approach, but microscopy still remains one of the most used and efficient tools in the characterization of gilding materials and their application techniques.

This work reports the first electrochemical molecularly imprinted polymer (MIP) sensor for Interleukin-1beta (IL-1β) detection, based on modified commercial screen-printed carbon electrode (SPCE) was successfully demonstrated. For this purpose, the carbon support was modified with a PEDOT/4-aminothiophenol layer prior to the MIP film to enhance sensitivity and signal stability. The MIP layer was constructed on top of this by electropolymerization of Eriochrome black T (EBT) in the presence of IL-1β. The several steps of the biosensor assembly was followed by Raman spectroscopy and electroanalytical techniques. Using electrochemical impedance spectroscopy (EIS), a linear response in the range of 60 pM to 600 nM, with a LOD of 1.5 pM with (S/N = 3) was obtained in neutral PBS. Selectivity tests of the MIP biosensor made in spiked synthetic serum samples as well as against other structurally related (Myoglobin, of similar shape and size) or competing compounds (Immunoglobulin G, also present in the human serum) confirmed the good selectivity of the biosensor. Overall, the biosensor described herein has the potential to provide a simple and quick way for on-site screening of IL-1β, with low sample/reagent consumption and enabling direct serum analysis, which constitutes a valuable alternative to other conventional methods.

This paper proposes the first results of a larger study on the behavior of gilded surfaces of polychrome heritage artefacts with the aim to understanding the surface patterns and roughness variations before and after specific treatments (burnishing and varnishing). This study can be useful to trace correlations between the compositional features, manufacturing and applications/elaboration processes of gilding layers and the pattern of the surface topography, and also some insights into the degradation/corrosion mechanisms. The results obtained on imitations of gilded surfaces can be further useful for recognizing fake surfaces in the authentication of artefacts from the antiquity markets.Two types of commercial imitations of gilded surfaces on a wooden support were considered: liquid 'gold' (Cu-Zn powder in a solvent) and 'gold' leaf (Cu-Zn leaf) applied over bole and gesso layers.A combined analytical approach using atomic force microscopy (AFM), optical microscopy (OM) and colorimetry (CIE L * a * b * system) was applied in order to better understand the behavior of the gilded-varnished surface and of the interface between the metal surface and the other preparative layers.

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