Hybrid composite materials based on TiO2/ graphene materials/ PVDF for germicidal applications
Mirela Petruta Sucheaa,c, Ioan Valentin Tudosea, Petronela Pascariua,b, Maria Orfanoua, Emmanouel Koudoumasa,c, Ryan Waldend,e, Christopher Goldend,e, Suresh C. Pillaid,e, Finn Purcell-Miltonf, Declan McCormackf,g
a Center of Materials Technology and Photonics, School of Engineering, Hellenic Mediterranean University (HMU), 71410 Heraklion, Crete, Greece;
b ”Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487, Iasi, Romania;
c National Institute for Research and Development in Microtechnologies - IMT Bucharest, 126A, Erou Iancu Nicolae Street, 077190, Voluntari-Bucharest, Romania
d Nanotechnology and Bio-Engineering Research Group, Department of Environmental Science, Atlantic Technological University, ATU Sligo, Ash Lane, Sligo, Ireland.
e Health and Biomedical (HEAL) Strategic Research Centre, Atlantic Technological University, ATU Sligo, Ash Lane, Sligo, Ireland.
f School of Chemical and BioPharmaceutical Sciences, Technological University Dublin, Central Quad, Grangegorman, Dublin 7, D07XH6K85, Ireland.
g Centre for Research in Engineering Surface Technology, CASH Building, Technological University Dublin, Blessington Road, Tallaght D24, D24 FKT9, Ireland
Abstract:
Hybrid composite materials based on TiO2/graphene in forms of nanoplatelets (GNP), graphene oxide (GO) and N-graphene oxide (N-GO)/PVDF with different concentrations of these components were developed by electrospinning technique, to be examined regarding germicidal applications. Samples were electrospun, using the same parameters for continuity, employing a Nanofiber Labs Electrospinner with a rotating drum collector. Optimised electrospinning parameters were set at the following: Positive voltage (at needle tip): 20 kV, Negative voltage (at drum collector): -20 kV, Flow rate: 3 mL/hr, Drum collector rotation speed: 100 rpm. Environmental factors were not recorded.
The obtained materials were characterised by X-ray diffraction (XRD), scanning electron micrograph (SEM) and energy dispersive X-ray analysis (EDX) and the effects of TiO2/graphene components concentration on materials properties were studied. Testing of composite materials, and the respective components, UV-induced photocatalytic antimicrobial activity was performed for four conditions: 1) bacteria in darkness, 2) bacteria in UV light, 3) bacteria + material in darkness, 4) bacteria + material + UV light. Each condition was tested for two biological replicates. The negative controls for these experiments were conditions 1 and 2, examining the baseline CFU/mL of the inoculum and the number of surviving bacteria after UV treatment alone. TiO2 exhibited antimicrobial activity in darkness with an LRV of 0.22. GO and N-GO were shown to possess a concentration-dependent antimicrobial activity in darkness, with N-GO having slightly less antimicrobial activity than GO alone. As with GO and N-GO, the addition of TiO2 reduced the LRV from 0.65 with UV light alone to only 0.08 when the TiO2 was present with UV light. Antimicrobial activity of electrospun composite fibres was not observed to exist using this method, most possibly because the method requires further optimisation or using a different method for testing electrospun fibres.
Acknowledgements
This work has been supported by the NATO Science for Peace and Security Programme, grant G5868. IMT’s contribution was partially supported by the Romanian Ministry of Education and Research through the μNanoEl, Cod: 23 07 core Programme. M.P.S. thanks to Dr. C. Romanitan, Dr. O. Brincoveanu and Dr. C. Pachiu for their support with characterization of some samples.
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