Aspergilli Response to Benzalkonium Chloride and Novel‐Synthesized Fullerenol/Benzalkonium Chloride Nanocomposite

Abstract

A comprehensive comparative analysis of antifungal potential of benzalkonium chloride and newly synthesized fullerenol/benzalkonium chloride nanocomposite was conducted to assess the possible impact of carbon-based nanocarrier on antimicrobial properties of the commonly used biocide. Physical characterization of synthesized nanocomposite showed zeta potential of +37.4 mV and inhomogeneous particles size distribution, with nanocomposite particles' dimensions within 30–143 nm and maximum number of particles at 44 nm. The effect of pure and fullerenol nanocarrier-bound biocide was evaluated in eight Aspergillus species. In mycelial growth assay, nanocomposite was more potent, as fungicidal effect of 1.04/0.6 μg mL−1 was obtained in all but one of the isolates (A. niger), while proportional concentration of pure biocide (0.6 μg mL−1) completely inhibited mycelial growth of only three Aspergillus species. However, conidia appear to be less susceptible to nanocomposite treatment, as lower fungistatic (MIC) and fungicidal (MFC) concentrations were obtained with biocide alone (MIC in range from 0.03 to 0.15 μg mL−1 and MFC from 0.075 to 0.45 μg mL−1). To a different degree, both substances stimulated aflatoxin B1 production and inhibited ochratoxin A synthesis. Very low mycelium biomass yield, in range from 1.0 to 3.0 mg dry weight, was documented in both biocide and nanocomposite enriched medium.

The impact of fullerenol nanoparticles on the growth of toxigenic Aspergillus flavus and aflatoxins production in vitro and in corn flour

“…Having in mind that values of the zeta potential within −30 to +30 mV may indicate certain instability of the system, it could be assumed that the change in zeta potential in YES broth led to the formation of bigger aggregates (20–100 nm) in comparison to the sole FNP solution (Figure 1a). The obtained results are in agreement with the previously published results (Borišev et al., 2016; Kovač et al., 2017; Kovač, Borišev, et al., 2018; Kovač, Boriš et al., 2020; Kovač, Šarkanj, et al, 2020; Unković et al., 2015; Vraneš et al., 2017). The sizes of nanoparticles are of great importance as their biological activity was proven to be size‐dependent, which was discussed previously in the literature (Chen al., 2010; Qiao et al., 2007) and is connected with the interplay between nanoparticles and the fungal cell wall.…”

“…However, Unković et al. (2015) reported that FNP concentration (0.0052 µg/mL), much lower than the investigated range in our research, also stimulated the production of AFB 1 , probably due to created stress conditions and defense mechanism of A. flavus . Furthermore, Kovač et al.…”

“…However, Unković et al (2015) reported that FNP concentration (0.0052 µg/mL), much lower than the investigated range in our research, also stimulated the production of AFB 1 , probably due to created stress conditions and defense mechanism of A. flavus. Furthermore, Kovač et al (2017) examined the impact of three different concentrations of FNP (10, 100, and 1000 ng/mL) on the A. flavus mycelium mass, as well as AFs production in YES broth every 24 h for 7 days.…”

“…One of the most attractive potential applications of FNP is as a nanocarrier of active principles, for example, anticancer drugs (Jović et al., 2016; Seke et al., 2016). Although being very potent and investigated agent, according to the literature, there are few scientific results advocating fullerenols effects on microfungi (Kovač et al., 2017, 2021; Kovač, Borišev, et al., 2018; Kovač, Šarkanj, et al., 2018; Kovač, Borišev, et al., 2020; Kovač, Šarkanj, et al., 2020; Unković et al., 2015, 2018). Considering the protective effect of FNP in biological models reported so far (Jović et al., 2016; Jaćević et al., 2017; Kojić et al., 2020; Petrovic et al., 2018) together with the increasing interest in fullerenol effect on fungi, this research has prompted the tendency to present FNP with a potential to control mycotoxins occurrence in food and feed in the future.…”

Impact of fullerol C60(OH)24 nanoparticles on the production of emerging toxins by Aspergillus flavus

“…The interaction between FNP and mycotoxigenic fungi (e.g. A. flavus) has been under research but literature are still limited 13,33,34 . However, it is known that FNP modulates oxidative status of A. flavus, consequently affecting the production of aflatoxins and their precursors 13,34 .…”