FTIR and nDSC as Analytical Tools for High-Concentration Protein Formulations

Abstract

Determination of a T(m (FTIR)) is feasible by the midpoint of the intensity-temperature plot of the arising intermolecular beta-sheet band. More significant results are obtained for proteins, which are predominantly composed of intramolecular beta-sheet elements as well as at higher protein concentrations. A further study was started to assess the predictability of long-term protein stability by T(m (FTIR)).

Recent applications of ATR FTIR spectroscopy and imaging to proteins

“…Similar problems are known to occur in the case of biopharmaceuticals such as therapeutic antibodies and antibody fragments [6]. Whilst it is likely that increases in protein concentration can result in protein aggregation, the effects of the surfaces that proteins encounter during isolation are far less well understood [7,8]. A much better understanding of the effects of surfaces on protein behaviour has major implications for the development of biomedical materials, clinical diagnostics and cellular adhesion [9,10,11].…”

Characterization of S-layer proteins of Lactobacillus by FTIR spectroscopy and differential scanning calorimetry

“…Differential scanning calorimetry (DSC) is a very powerful method for the study of phase transition processes, providing very precise and direct measure of the associated heat fluxes. It has been used to investigate the melting temperatures of proteins as well as protein denaturation and the results successfully correlated with the changes observed in the Amide I infrared spectral region (and also, less frequently, in other spectral regions) upon heating [12,24].…”

“…In agreement with the DSC results, the observed spectroscopic changes were found to be irreversible. The phase transition temperatures (Tm FTIR ) were estimated from the sigmoidal fitting midpoint of the dependence with temperature of Amide I maximum in the original spectra or of specific structure related modes in second derivative spectra [12].…”

“…FTIR is a well-established methodology that has been extensively used for the elucidation and analysis of the secondary structure of proteins [1,[10][11][12]. The singular advantage of FTIR over other techniques is that spectra can be obtained for proteins in a wide range of environments, e.g., in the crystalline state, solution and on different surfaces, including polymers, metals and bioceramics [13,14 among …”

“…The second derivative analysis permits the direct separation of the Amide I band into its components and thus, provides additional structural information. Absorbance bands in Table 2 Empirical assignment of secondary structure elements to different amide I band components in proteins [23,24] Wavenumber (cm the original spectrum are revealed as negative bands in the second derivative spectrum, whereby the band position is preserved [11,12]. In this context, the analysis of the second derivative of the Amide I bands has been performed for all the strains under study (Fig.…”