Applications of ATR-FTIR spectroscopic imaging to biomedical samples

Abstract

Protein crystallization is of strategic and commercial relevance in the post-genomic era, due to its pivotal role in structural proteomics projects. Although protein structures are crucial for understanding the function of proteins and to the success of rational drug design and other biotechnology applications, obtaining high quality crystals is a major bottleneck to progress. The major means of obtaining crystals is by massive-scale screening of a target protein solution with numerous crystallizing agents. However when crystals appear in these screens, one cannot easily know if they are crystals of protein, salt or any other molecule that happens to be present in the trials. We present here a method based on ATR-FTIR imaging that reliably identifies protein crystals through a combination of chemical specificity and the visualising capability of this approach, thus solving a major hurdle in protein crystallization. ATR-FTIR imaging was successfully applied to study the crystallization of thaumatin and lysozyme in a high-throughput manner, simultaneously from six different solutions. This approach is fast as it studies protein crystallization in situ and provides an opportunity to examine many different samples under a range of conditions.

Total internal reflection spectroscopy for studying soft matter

“…Kazarian and Chan have recently reviewed biomedical applications of imaging 183,184 and technical aspects. 53 A single-reflection geometry must be used for ATR-IR imaging, limiting the sensitivity.…”

Multivariate Analysis for Fourier Transform Infrared Spectra of Complex Biological Systems and Processes

“…In the case of complex biological systems it provides simultaneously, in a single measurement, information on the main biomolecules, such as lipids, proteins, nucleic acids, and carbohydrates, requiring also a very limited amount of sample. For these reasons, it became recently a very attracting tool for biomedical research [20,[22][23][24], being successfully employed for the study of several biological systems, from intact cells [6,7,25] to tissues [11,26,27] and whole model organisms (i.e. the nematode Caenorhabditis elegans) [9,28].…”

Correcting the Effect of Refraction and Dispersion of Light in FT-IR Spectroscopic Imaging in Transmission through Thick Infrared Windows

“…The applications of FTIR imaging are steadily expanding and include pharmaceutical materials, 1-3 polymer processes, 4-5 biological samples, 6 forensic studies 7 as well as art and heritage samples. 8 FTIR imaging is mostly conducted either in transmission, reflectance or Attenuated Total Reflection (ATR) modes.…”