XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
252
T2: P–37
ATR-FTIR studies on interactions of N-methylacetamide with selected
osmolytes
Emilia Kaczkowska
1
, Piotr Bruździak
1
, and Janusz Stangret
1
1
Department of Physical Chemistry, Gdańsk University of Technology, Narutowicza 11-12, 80-233
Gdańsk, Poland, e-mail: ekaczkowska@poczta.onet.pl
It is well-known that the three-dimensional protein structure determines its proper biological
function. Native proteins structures are characterized by certain thermal stability which can be
modify by osmolytes, small organic compounds, naturally occurring in cellular environment.
Their presence allows plants and animals to settle areas with unfavorable salinity, temperature,
pressure, etc. According to their effect on protein, osmolytes can be divided into two distinct
groups: stabilizers and destabilizers. The differences in the mechanism of proteins stabilization
by these groups are not well understood. It was determined that both stabilizing and
destabilizing osmolytes can interact directly with the amino acid side chains [1]. It was also
experimentally determined that hydrogen bonds were also formed between the protein backbone
and urea, a representative of destabilizing osmolytes. If there are any differences in the
interaction of the stabilizing and destabilizing osmolytes with the protein, they may be
pronounced in the interactions between the small organic molecules and the polypeptide chain.
The purpose of our project is to determine, by means of the ATR-FTIR spectroscopy and with
selected model molecules, whether such differences exist and what is the nature of interactions
in such systems.
N-methylacetamide (NMA) molecule has been selected as a minimal model of protein
backbone, due to its chemical structure and similar hydration pattern [2]. Interactions with
various osmolytes, glycine as stabilizer and urea as destabilizer, are derived with the well
established difference spectra method [3], which can give information on the number of
interacting molecules in such systems and spectral features of such affected molecules, which
can be interpreted in the context of interaction type and strength.
Keywords: FTIR; osmolytes; N-methylacetamide
References
[1] A. Panuszko, P. Bruździak, E. Kaczkowska. J. Stangret, J.Phys.Chem.B. 120 (2016) 11159.
[2] A. Panuszko, B. Adamczak, J. Czub, E. Gojło, J. Stangret, Amino Acids 48 (2015) 1737.
[3] P. Bruździak, PW. Rakowska, J. Strangret, Appl. Spectrosc. 66 (2012) 1302.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
253
T2: P–38
Comparative analysis of carbon fibrous membrane
modified by ceramic nanofillers
Ewa Stodolak-Zych
1
, Wojciech Lisiecki
1
, Magdalena Kocot
2
, and Piotr Jeleń
3
1
Department of Biomaterials, Faculty of Materials Science and Ceramics, AGH University
of Science and Technology, A. Mickiewicz 30 Ave. 30-059 Krakow, Poland,
e-mail: stodolak@agh.edu.pl
2
Faculty of Electrical Engineering, Automatics, Computer Science and Biomedical Engineering,
AGH University of Science and Technology, A. Mickiewicz 30 Ave. 30-059 Krakow, Poland
3
Department of Silicate Chemistry and Macromolecular Compounds, Faculty of Materials Science
and Ceramics, AGH-University of Science and Technology, A. Mickiewicz 30 Ave. 30-059 Krakow,
Poland
Carbon nanofibers obtained by the electrospinning process with polymer precursor are well
known and applicable in many medical and technical areas [1, 2]. Some authors compare
potential of carbon nanofibers (CNF) with carbon nanotubes (CNT) because of their similar
shape coefficient (length to diameter ratio of carbon fillers which in these materials is >> 100).
While modification of carbon nanotubes is a difficult and ineffective process, the modification
of carbon nanofibers is more effective: it can be implemented on two possible ways [1]. In the
first method: the fiber volume can be modified by nanoadditives in preparation of an
electrospinning solution. In the second way the fiber is chemically treated which functionalize
the fibers surface in reactive chemical groups capable of further reaction on their surface. The
second method of the CNFs functionalization is similar to the one used in case of carbon
nanotubes [2].
In this work, polymer precursors were modified with three types of commercial
nanoparticles: hydroxyapatite (HAp, <200nm, Sigma Aldrich), tricalcium phosphate (TCP,
<200nm, Sigma-Aldrich) and nanometric silica (SiO
2
, 10–20 nm, Sigma Aldrich). Nanofillers
lead to polymer solution in 5% w/w. allowed to stable spinning solutions and to obtain a fibrous
polymer-ceramic membrane. The thermal conversion process (oxidation and carbonization) was
carried out, resulting in the formation of nanocomposite carbon membranes. Each membrane
thermal treatment step was monitored by FTIR spectroscopy using the ZnSe/Ge crystal ATR
technique. For all types of polymeric fiber membranes, the characteristic bands of the pure PAN
have been observed. Same changes in band intensity are observed after the leading of nanofillers
into the polymer matrix (HAp, TCP: 1080 cm
–1
, 1450 cm
–1
and SiO
2
: 810 cm
–1
). The oxidation
process (240°C/30 min) leads to the crosslinking, cyclization and dehydrogenation of the
polymer chain while retaining the nanofiller bands. Two stage of carbonization process carried
out in a protective atmosphere (960°C/5 min and 1000°C/5 min) causes a change in the relations
of the bands G, D, and G' visible in Raman spectra (FT Raman). The kind of nanofiller affects
the intensity of the above bands and indicates a higher-order in the structure of the carbon
nanofiber in the following sequence: CNF/HAp>CNF/TCP~CNF/SiO
2
. All of fibrous carbon
membranes are bioactive: They induce apatite nuclei in the SBF that is visible in the scanning
microscope (SEM/EDS) as well as FTIR-ATR spectra.
Keywords: carbon nanofibers, membrane fibres, nanocomposite, ceramic nanofillers, bioactivity
Acknowledgment
This work has been supported by the National Science Center, Poland, under grant no. UMO-
2014/13/B/ST8/01195
References
[1] A. Fernández, P. Peretyagin, W. Solís, R. Torrecillas, A. Borrell, J. Nanomater. 12 (2015) 1.
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