Stage 1: 27.06-31.12.2022

The goal of the NanoClean project is to synthesize and evaluate the disinfectant activity of metal oxide nanoparticles on the duodenoscope, in order to improve the quality of medical care in this sector.

A1.1. Synthesis and characterization of MeO-NPs: Fe₃O₄, CeO₂, TiO₂, ZnO₂, Ga₂O₃, MgO and Ag₂O (M1-M6)

Within activity A1.1, there were synthesized simple metal oxides nanoparticles, namely: Fe₂O₃, CeO₂, TiO₂, ZnO₂, Ga₂O₃, MgO and Ag₂O, by using previously  reported methods, with some modifications. Due to the colloidal instability of some of the synthesized nanoparticles, it was necessary to stabilize them by coating with polymers. Thus, the Fe₃O₄ nanoparticles, which show a strong tendency to agglomerate due to their magnetic properties, were coated with polyethylene imine (PEI), resulting in nanoparticles with good colloidal stability. Also in case of CeO₂ nanoparticles, due to colloidal instability, it was decided to cover them with PEI. However, in order to obtain a good colloidal stability, it was necessary to crosslink the PEI coating of the CeO₂ nanoparticles with glutaraldehyde (GA) followed by the inactivation of the aldehyde groups of the unreacted GA, thus obtaining stable nanoparticles with small sizes. Due to the specific instability of these types of oxides,  zinc peroxide (ZnO₂) and silver oxide (Ag₂O) nanoparticles were coated with alginic acid (Alg) and sodium citrate (Cit). Nanoparticles of titanium (TiO₂), gallium (Ga₂O₃) and magnesium (MgO) oxides were not stabilized by coating with polymers.

For all types of synthesized metal oxide nanoparticles, their structures were confirmed using different structural characterization techniques, such as FTIR, DRX, XPS or Raman, depending on particularities of each type of metal oxide. Also, the nanoparticles were characterized in terms of morphology, dimensions and stability using TEM and DLS techniques. From these studies it was observed that all the synthesized nanoparticles show a tendency to agglomerate in aqueous medium. This aggregation tendency was reduced by covering the nanoparticles with a polymer, thus obtaining nanoparticles with smaller sizes and good colloidal stability.

A1.2. Synthesis and characterization of mixed MeO-NPs: Fe₃O₄ - CeO₂, TiO₂ – CeO₂, CeO₂ – ZnO₂ (M4-M9)

As part of activity A1.2, there were synthetized hybrid metal oxide nanoparticles  Fe₃O₄ - CeO₂, using the precursors previously synthesized during activity A1.1, namely Fe₃O₄-PEI and CeO₂-PEI-GA-PEI. To confirm the structure of Fe₃O₄-CeO₂-PEI hybrid nanoparticles, characterization techniques such as FTIR, Raman and EDX were used, observing that the spectrum of hybrid nanoparticles simultaneously presents all the signals characteristic of both precursors, thus confirming the formation of mixed metal oxide nanoparticles. In this case, a morphological and dimensional characterization was performed. From the performed TEM and DLS analyses, it can be observed that the simple metal oxides were conjugated in spherical matrices of the polymer shell of PEI crosslinked with GA. 

A1.3. In vitro screening of MeO-NPs antimicrobial activity and cytotoxicity (M2-M12)

Within the activity A1.3. the antimicrobial activity and biocompatibility of the synthesized metal oxide nanoparticles were evaluated. Ag₂O and ZnO₂ nanoparticles have the best antibacterial activity, destroying in 40 minutes all the cells of K. pneumoniae, S. typhimurium and E. faecalis, bacterial strains with a high incidence in nosocomial infections caused by the use of duodenoscopes at global level. At the same time, these nanoparticles prove that any traces of the compound left on the duodenoscope after high-grade disinfection would not cause the mortality of normal gingival fibroblasts and normal human dermal fibroblasts, being thus biocompatible.

Dissemination:

1. Articles published in ISI journals:

1. Fifere, A.; Turin-Moleavin,I.-A.; Rosca, I. Does ProtocatechuicAcid Affect the Activity of Commonly Used Antibiotics and Antifungals? Life 2022, 12, 1010.  IF: 3.251 (Q2)

https://doi.org/10.3390/life12071010 

2. Corciovă, A.; Mircea, C.; Burlec, A.F.; Fifere, A.; Moleavin, I. A.; Sarghi, A.; Tuchiluș, C.; Ivănescu, B.; Macovei, I. Green Synthesis and Characterization of Silver Nanoparticles Using a Lythrum salicaria Extract and In Vitro Exploration of Their Biological Activities. Life 2022, 12, 1643. IF: 3.251 (Q2)

https://doi.org/10.3390/life12101643

2. Papers presented at national/international scientific conferences:

1. Roșca, I.; Fifere, A.; Turin-Moleavin, I.-A.; Ursu, E.-L., Iacobescu (Sârghi), A.; Bălan, G.G. New Options For Duodenoscope Reprocessing Using Metal Oxide Nanoparticles. Conferința Națională De Chimie Editia XXXVI Călimănești-Căciulata 4-7 octombrie 2022 – oral communication.

2. Fifere, A.; Iacobescu (Sârghi), A.; Turin-Moleavin, I.-A.; Roșca, I.; Pinteală, M. Iron Oxide Nanoparticles Loaded With Protocatechuic Acid And Antibiotics As Free Radical Scavengers And Antimicrobial Agents. Conferința Națională De Chimie Editia XXXVI Călimănești-Căciulata 4-7 octombrie 2022 – oral communication.

3. Turin-Moleavin, I.-A.; Iacobescu (Sârghi), A.; Roșca, I.; Fifere, A.; Pinteală, M. Magnetic Nanoantioxidants Based On Magnetite Conjugated With Cerium Oxide. Conferința Națională De Chimie Editia XXXVI Călimănești-Căciulata 4-7 octombrie 2022 – poster.

4. Ursu, C.; Roșca, I.; Iacobescu (Sârghi), A.; Ursu, E.-L. Laser Assisted Synthesis of Ag₂O/Ag Nanoparticles With Application In Duodenoscope Disinfection. Conferința Națională de Chimie Editia XXXVI Călimănești-Căciulata 4-7 octombrie 2022 – poster.

5. Iacobescu (Sârghi), A.; Fifere, A.; Turin-Moleavin, I.-A.; Angeli, A.; Pinteală, M. Electron Spin Resonance Spectroscopy For The Study Of Organotelluride - Mediated Generation Of Free Radicals. Conferința Națională de Chimie Editia XXXVI Călimănești-Căciulata 4-7 octombrie 2022 – poster.