Chemical Education Today
Research Advances: Improved Methods for Detecting Art Forgeries and Blood Types by Angela G. King Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27109, United States
[email protected] Imaging Method for Eye Disease Used To Eye Art Forgeries Scientists in Poland are describing how a medical imaging technique, called optical coherence tomography (OCT), has taken on a second life in revealing forgery of an artist's signature and changes in inscriptions on paintings that are hundreds of years old (1). Researcher Piotr Targowski notes that easel paintings prepared according to traditional techniques consist of multiple layers. The artist, for instance, first applies a glue sizing over the canvas to ensure proper adhesion of later layers. Those layers may include an outline of the painting, the painting itself, layers of semitransparent glazes, and finally transparent varnish. Art conservators and other experts resort to a variety of technologies to see below the surface and detect changes, including forged signatures and other alterations in a painting. But those approaches may damage artistic treasures or may not be sensitive enough to detect finer details. The scientists describe how OCT, used to produce threedimensional images of the layers of the retina of the eye, overcomes those difficulties. They used OCT to analyze two oil paintings from the 18th and 19th centuries. In one, “Saint Leonard of Porto Maurizio”, OCT revealed evidence that the inscription “St. Leonard” was added approximately 50 years after completion of the painting. In the other, “Portrait of an Unknown Woman”, OCT found evidence of the possible of forgery of the artist's signature (Figure 1). Educators may be able to introduce this new analytical application while integrating art and chemistry. Additional resources available to aid this effort include the use of radiochemistry or thermoluminescence in forgery detection or even an analytical course centered on art and archeology (2- 4). A very recent publication for instructors in nonscience majors courses is also available (5). Because Celebrating Chemistry and Art was the theme of 2001 National Chemistry Week, this Journal compiled an excellent list of resources for educators to integrate the two subjects (6). First Paper “Dipstick” Test for Determining Blood Type Scientists are reporting development of the first “dipstick” test for instantly determining a person's blood type at a cost of just a few pennies (7). The newly developed test could be a boon for improving health care in developing countries. The test also could be useful in veterinary medicine, for typing animals' blood in the field, the scientific team notes. The new method is based on the principle that red cell agglutination, triggered by specific antigen interaction, drastically decreases blood wicking and 1284
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Figure 1. The oil painting on the left fluoresces when exposed to ultraviolet light (right), but evidence of signature forgery remained unseen until a new, noninvasive imaging technique was used. Image courtesy of Waldemar Grzesik, Institute for the Study, Restoration, and Conservation of Cultural Heritage, Nicolaus Copernicus University, in Toru n, Poland.
transport on paper or chromatographic media. Blood is a stable colloid suspension of red and white blood cells and platelets in an aqueous buffer solution, which also contains biomacromolecules. Some of the biomacromolecules include glycoproteins and carbohydrates adsorbed onto the surface of the red blood cells that determine blood type and tissue. The agglutination process also considerably enhances the chromatographic separation (elution) of the blood components, especially the red cells from the plasma. Gil Garnier and colleagues explain that determining a patient's blood type is critical for successful blood transfusions, which save millions of lives each year worldwide. There are four main blood types: A, B, AB, and O. Use of the wrong blood type in a patient can be fatal. Current methods for determining blood type require the use of sophisticated instruments that are not available in many impoverished parts of the world. An inexpensive portable test could solve that problem. The scientists describe development of prototype paper test strips impregnated with antibodies to the antigens on red blood cells that determine blood type. In lab tests using blood samples from human volunteers, the scientists showed that a drop of blood placed on the strip caused a color change that indicated blood type. The results were as accurate as conventional blood typing. The experiments involved mixing blood samples (Aþ, Bþ, ABþ and Oþ) with antibody solutions. The blood mixed with its corresponding antibody and agglutinated but transported differently than stable blood solutions (blood mixed with a nonspecific antibody) when deposited on a paper strip.
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Vol. 87 No. 12 December 2010 pubs.acs.org/jchemeduc r 2010 American Chemical Society and Division of Chemical Education, Inc. 10.1021/ed1008987 Published on Web 10/06/2010
Chemical Education Today
“The paper diagnostics manufacturing cost is a few pennies per test and can promote health in developing countries”, the report notes. This research is related to published chemical education resources on forensic blood typing (8) and the role of certain enzymes in blood typing (9). This Journal has also published molecular models related to the chemistry of blood typing (10). Literature Cited 1. Targowski, P.; Iwanicka, M.; Tyminska-Widmer, L.; Sylwestrzak, M.; Kwiatkowska, E. Structural Examination of Easel Paintings with Optical Coherence Tomography. Acc. Chem. Res. 2010, 43, 826–836. 2. Rogers, F. Chemistry in Art. Radiochemistry and Forgery. J. Chem. Educ. 1972, 49, 418–419. 3. Rogers, F. Chemistry and Art. Thermoluminescence and Forgery. J. Chem. Educ. 1973, 50, 388–389.
r 2010 American Chemical Society and Division of Chemical Education, Inc.
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4. Beilby, A. Art, Archaeology, and Analytical Chemistry: A Synthesis of the Liberal Arts. J. Chem. Educ. 1992, 69, 437–439. 5. Nivens, D.; Padgett, C.; Chase, J.; Verges, K.; Jamieson, D. Art, Meet Chemistry; Chemistry, Meet Art: Case Studies, Current Literature, and Instrumental Methods Combined To Create a Hands-On Experience for Nonmajors and Instrumental Analysis Students. J. Chem. Educ. 2010, 87, DOI: 10.1021/ed100352f. 6. Jacobsen, E. JCE Resources for Chemistry and Art. J. Chem. Educ. 2001, 78, 1316–1321. 7. Khan, M.; Thouas, G.; Shen, W.; Whyte, G.; Garnier, G. Paper Diagnostic for Instantaneous Blood Typing. Anal. Chem. 2010, 82, 4158–4164. 8. Kobilinsky, L.; Sheehan, F. Human Blood Typing: A Forensic Science Approach Part I: Background. J. Chem. Educ. 1988, 65, 531–533. 9. Rose, N.; Palcic, M.; Evans, S. Glycosyltransferases A and B: Four Critical Amino Acids Determine Blood Type. J. Chem. Educ. 2005, 82, 1846–1852. 10. Coleman, W. Chemistry of Blood Type. J. Chem. Educ. 2005, 82, 1853.
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