Antibacterial potential of electrochemically exfoliated graphene sheets

Electrochemically exfoliated graphene is functionalized graphene with potential application in biomedicine. Two most relevant biological features of this material are its electrical conductivity and excellent water dispersibility. In this study we have tried to establish the correlation between graphene structure and its antibacterial properties. The exfoliation process was performed in a two electrode-highly oriented pyrolytic graphite electrochemical cell. Solution of ammonium persulfate was used as an electrolyte. Exfoliated graphene sheets were dispersed in aqueous media and characterized by atomic force microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X photoelectron spectroscopy, X-ray diffraction, electron paramagnetic resonance, zeta potential, contact angle measurements and surface energy. Antibacterial assays have shown lack of the significant antibacterial activity. Major effect on bacteria was slight change of bacteria morphology. Membrane remained intact despite significant change of chemical content of membrane components.This is the peer reviewed version of the paper: Marković, Z. M., Matijašević, D. M., Pavlović, V. B., Jovanović, S. P., Holclajtner-Antunović, I. D., Špitalský, Z., Mičušik, M., Dramićanin, M. D., Milivojević, D. D., Nikšić, M. P., & Todorović Marković, B. M. (2017). Antibacterial potential of electrochemically exfoliated graphene sheets. Journal of Colloid and Interface Science, 500, 30–43. [https://doi.org/10.1016/j.jcis.2017.03.110][https://www.sciencedirect.com/science/article/abs/pii/S0021979717303776?via%3Dihub

Surface modification of low-density polyethylene with poly(2-ethyl-2- oxazoline) using a low-pressure plasma treatment

Low-density polyethylene (LDPE) is a suitable polymer for biomedical applications due to its good physiochemical properties, but its insufficient biocompatibility is often an issue. Therefore, biocompatible substances such as those based on 2-ethyl-2-oxazoline seem to be a good choice to increase the LDPE biocompatibility. In this work, the surface modification of LDPE with poly(2-ethyl-2-oxazoline) with two different end-groups was investigated. This modification led to the improvement of surface and adhesion properties, which were investigated by several analytical methods. The low-temperature plasma treatment of the LDPE surface was sufficient to create binding sites for the permanent attachment of poly(2ethyl-2-oxazoline) chains. This was confirmed by infrared spectroscopy and X-Ray photoelectron spectroscopy. It was found that the polymer containing the acrylic end-group was well attached to the LDPE surface. 2013 Elsevier Ltd. All rights reserved.This work was supported by the Slovak Grant Agency VEGA for projects Nr. 2/0064/10 , Nr. 2/0151/12 , and Nr. 2/0185/10 ). The Center for Materials, Layers and Systems for Applications and Chemical Processes under Extreme Conditions was supported by the Research & Development Operational Program funded by the ERDF. Electron microscopy at IMC was performed with financial support through grant TACR TE01020118 .Scopu

Thermal and electrical characterization of multi-walled carbon nanotubes reinforced polyamide 6 nanocomposites

In this study composites of polyamide 6 and multiwalled carbon nanotubes (MWCNT) were prepared by diluting a masterbatch using melt mixing. Differential scanning calorimetry was employed in order to investigate the influence of nanotubes on the thermal transitions of polyamide 6. Significant changes are reported on crystallization and glass transition by the addition of nanotubes. The results are discussed in terms of polymer-filler interactions. Dielectric relaxation spectroscopy measurements were performed to study both the electrical and dielectric properties of the nanocomposites. Percolation threshold is calculated to be at 1.7 vol.% MWCNT