Infrared spectroscopy

: a groundbreaking tool for monitoring mammalian cells’ processes

Abstract

Fourier Transform Infrared (FTIR) spectroscopy is a high sensitive technique, which is able to detect vibrational modes of biomolecules, with a consequent world of applications. In the present work, the potential of this technique, working in the mid-infrared region (MIR), was explored for studying three distinct mammalian cells’ processes, working in a rapid, reagent free and in a high-throughput mode. FT-MIR spectroscopy was applied to monitor the expansion of human mesenchymal stem cells (hMSCs) in microcarriers and cultured in spinner flasks. It was possible to develop partial least squares (PLS) regression models to quantify, directly from the spectral data, key analytes, e.g., glucose, lactate and ammonia. Also, information about the cellular growth stage was possible to be extracted by the development of principal component analysis (PCA) models. Additionally, were developed PLS regression models for estimating the transfection efficiency in a cell population without the need for a reporter gene. The model is valid for two distinct cell lines, the adherent cell line AGS and the semi-adherent cell line HEK, both transfected with pVAX containing the GFP gene. Besides an accurate estimation of the transfection efficiency, it was also possible to extract some meaningful information about the biochemical cellular effect of the transfection reagent on cells and the transfection event itself, proving the sensitiveness of the technique. Finally, AGS cells infected with ten different Helicobacter pylori strains were analyzed based on FT-MIR spectral data. The different H. pylori strains presented different CagA/VacA genotypes, and were isolated from patients with different gastric pathologies (non-ulcer dyspepsia, peptide ulcer disease and gastric cancer). It was possible to differentiate cell samples according to the strain causing the infection, through PCA and cluster analysis.

Date of Award	3 Jan 2014
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Cecília R.C. Calado (Supervisor) & Marta Belchior (Co-Supervisor)