Gold—Polyoxoborates Nanocomposite Prohibits Adsorption of Bacteriophages on Inner Surfaces of Polypropylene Labware and Protects Samples from Bacterial and Yeast Infections

Abstract

Bacteriophages (phages) are a specific type of viruses that infect bacteria. Because of growing antibiotic resistance among bacterial strains, phage-based therapies are becoming more and more attractive. The critical problem is the storage of bacteriophages. Recently, it was found that bacteriophages might adsorb on the surfaces of plastic containers, effectively decreasing the titer of phage suspensions. Here, we showed that a BOA nanocomposite (gold nanoparticles embedded in polyoxoborate matrix) deposited onto the inner walls of the containers stabilizes phage suspensions against uncontrolled adsorption and titer decrease. Additionally, BOA provides antibacterial and antifungal protection. The application of BOA assures safe and sterile means for the storage of bacteriophages.

Container material dictates stability of bacteriophage suspensions: Light scattering and infectivity measurements reveal mechanisms of infectious titre decay

“…While Richter et al observed a strong correlation between contact angle and titre loss, we have observed no clear correlation between contact angle and IT decay across a variety of container material and surface treatments. We observed dramatic titre loss in polypropylene containers, which has been shown to be a consistently unsuitable material with regards to phage stability (Duyvejonck et al, 2021; Richter et al, 2021; Wdowiak et al, 2021). Contrary to our expectations, substituting standard polypropylene with low protein‐binding formulations exacerbated the problem, resulting in IT loss of 4.65 and 4.22 log 10 loss of phages P68 and gh‐1 respectively.…”

“…This latter result is more consistent with our own observation of significant IT decay in glass vials which had a contact angle of 13.6°. Further supporting a hypothesis of nanotopographical modulation of phage stability, Wdowiak et al demonstrated that coating of container surfaces with gold—polyoxoborate nanocomposites prevented adsorption of phages on polypropylene labware (Wdowiak et al, 2021). As in the earlier work of Richter et al, this protective effect was similarly attributed to modification of the wettability.…”

“…Recent publications posited a correlation between wettability of labware material and modulation of stability of phage suspensions stored in them (Richter et al, 2021; Wdowiak et al, 2021). Richter et al found that an increase in container surface contact angle resulted in a transition to instability above a threshold of 95°, which the authors propose as a heuristic to approximately judge suitability of labware for phage storage.…”

“…Particles resembling phages and phage aggregates were observed only on BSA-treated polypropylene. Scale bars indicate 200 nm Wdowiak et al, 2021). Richter et al found that an increase in container surface contact angle resulted in a transition to instability above a threshold of 95°, which the authors propose as a heuristic to approximately judge suitability of labware for phage storage.…”

“…These phenomena have important implications not only for future phage research but also in retrospect when considering findings of past publications that may have failed to control for such an effect. As a result, there is now interest in treatment of container surfaces (Wdowiak et al, 2021) and optimization of phage buffer composition (Duyvejonck et al, 2021) to mitigate loss of infectious titre.…”