George Mason scientists explore adhesives to advance preservation of historical texts

What does science have to do with the conservation of historical texts? Everything. 

Rocío Prisby, a biosciences doctoral student at George Mason University, led the first comprehensive analysis of proteins found within wheat starch-based and flour-based pastes used in historic texts. 

This study produced a working database for historians to cross-reference for their own samples that will ultimately result in greater understanding of the evolution of adhesives, while also providing a starting point to determine the best conservation practices for bookbinding and paper conservation.

Each sample tells a story—someone in the 1500s mixing flour, water, and milk in a large bowl to create a paste that binds paper; another in the 1600s hoping to improve their glue’s viscosity with a dash of egg. But each story is different, and the uncertainty in these mixtures reinforces the need for a central database to aid in historical research. 

“We still don’t know when in human history people stopped mixing flour and water and shifted to starches,” said Prisby, who also has a bachelor’s degree in chemistry from George Mason. “So, you can’t make any assumptions for what a book’s glue makeup might be.” 

Prisby worked alongside George Mason researchers Alessandra Luchini and Lance Liotta of the Center for Applied Proteomics and Molecular Medicine, as well as Caroline Solazzo from the Smithsonian Museum Conservation Institute. Their study, published in the Journal of Proteome Research, involved extracting wheat proteins from three small leather cover samples obtained from the National Library of Medicine. 

Their methodology sought to establish a protocol capable of identifying wheat proteins, along with collagen and other proteins commonly found in leather and adhesives. The results were then compared to a database containing collagen proteins from various sources like cattle, sheep, goats, and chicken eggs, as well as wheat proteins from common wheat. 

Analysis of historical samples indicates a shift away from using whole wheat for glue production towards the use of starch-based glues. This transition has led to a noticeable decrease in protein content, as the starch extraction process significantly reduces the protein levels in the final product.

Consequently, samples containing starch-based glue exhibit considerably lower protein concentrations compared to those containing traditional wheat-based glue. Environmental conditions and extraction techniques also influence protein composition. Prisby said understanding the chemical changes in wheat-based adhesives is crucial for conservation and restoration practices, particularly in comprehending the degradation of samples over time. 

The study’s researchers suggest that further investigation into wheat pastes and other plant-based adhesives should consider a diverse array of factors, including preparation methods, additives, aging processes, and the extensive variety and composition of the raw materials used.

A native of Argentina, Prisby (formerly Cornero) began her chemistry studies at a local university before moving to the United States. She continued her studies at Northern Virginia Community College and was in the first ADVANCE cohort to transfer to George Mason.

Prisby began researching proteins as an undergraduate in the College of Science’s Aspiring Scientists Summer Internship Program (ASSIP). In that early research, she studied the proteins in honey to monitor the health of the local environment while also seeking to identify a biomarker that might detect and diagnose diseases in honey bees. 

It was through that project that Prisby met Luchini and became interested in her lab’s work in proteomics.

“Dr. Luchini is a great mentor. She dedicates so much time to her students,” said Prisby. “It doesn’t matter what knowledge or experience level you’re at, she meets you where you are.”

When Prisby graduated from George Mason with her undergraduate degree in chemistry, it was Luchini who encouraged her to pursue a PhD in Biosciences.