Research

Research

I have three main areas of research:

  • Scientific research for the conservation of cultural heritage
  • Development and applications of NMR Crystallography
  • Developing instrumentation for in situ high-pressure NMR under Magic Angle Spinning

Cultural Heritage

My research in the cultural heritage field is focused on using Nuclear Magnetic Resonance (NMR) in a non-invasive way to study precious objects of cultural heritage. These studies can help identify the best ways to conserve our world heritage.

I started working in the cultural heritage field during my PhD, when I was using mobile NMR to analyze ancient mummies and bones to assess their state of conservation. Some of the “samples" I was working on included Oetzi – the Iceman, a Peruvian mummy, and Egyptian mummy head and several bones, including the tibia of Charlemagne.

Ancient mummies and bones studied by Mobile NMR

Right now I’m working on two art-related projects in collaboration with Prof. Bernhard Bluemich from RWTH-Aachen University in Germany: 

1 – Developing a method that can help us identify forgeries in paintings – collaboration with the State Criminal Police Office in Berlin. For this project we analyze the forgeries of a famous art forger named Wolfgang Beltracchi. We compare our NMR results on the forgeries with the results we obtain on the authentic paintings to establish a protocol to discriminate between forgeries and authentic paintings. 

Forgeries of Wolfgang Beltracchi
Our experimental setup for the violin measurements in the Ashmolean Museum

2 – Analyzing old master violins to understand the science behind building such exquisite instruments – collaboration with the Ashmolean Museum in Oxford. In this project we analyze the violins from the Ashmolean collection (including Amati, Stradivari, and Ruggeri violins) to understand the types of treatments that were used in the past for preserving these violins. For our experiments we use mobile NMR as a non-invasive tool to study these precious violins. 

NMR Crystallography

The development of NMR crystallography (NMRX), a method that employs a combined experimental and computational approach for structural elucidation of powdered crystalline materials, opened new paths into exploring pharmaceutical polymorphism. Solid-state NMR investigation of pharmaceutical drugs is faced with two main drawbacks: the low sensitivity of NMR experiments involving nuclei such as 13C, 15N at natural abundance and long 1H T1 relaxation times of many pharmaceuticals. The consequence of these cumulative effects is a very long experimental time for signal averaging required to obtain sufficiently high signal-to-noise ratio in two-dimensional NMR spectra, which are essential for the unambiguous chemical shift assignment of the investigated structure.

Our research is centered on further developing NMR crystallography by using new experimental and computational techniques that are more appropriate for studying complex organic molecular crystals. Experimentally we make use of the developments in Dynamic Nuclear Polarization (DNP)-enhanced solid-state NMR to reduce the experimental time, allowing us to tackle more complex structures. Computationally we focus on different computational crystal structure prediction protocols to predict new polymorphs of organic molecular crystals.

In NMR crystallography we combine the solid-state NMR experiments and the computational crystal structure prediction to determine de novo crystal structure of materials. In my research I’m interested in applications of NMR Crystallography to study pharmaceutical polymorphism.

Illustration of the NMR Crystallography protocol for crystal structure determination from powder samples

High-pressure NMR under Magic Angle Spinning

Pharmaceuticals and materials, in general, can exhibit polymorphism because of different physical and chemical conditions required to stabilize a certain crystal form. This means that they can have varying crystal structures with different number of molecules in the unit cell, different unit cell dimensions, space groups, etc. I’m mostly interested on how these polymorphism characteristics vary when the materials are subjected to high pressures. For this purpose, in my lab, we are developing a high-pressure NMR setup to enable the acquisition of high-pressure solid-state NMR experiments in situ in the magnet under magic angle spinning. This will enable the investigation by NMR of high-pressure polymorphs in pharmaceuticals and other materials.

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