Anti-biofilm and anti-virulence effects of silica oxide nanoparticle-conjugation of lectin purified from Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa lectin is purified and nanoparticle-conjugated in an attempt to inhibit biofilm formation. Thirteen (23.6%) P. aeruginosa isolates are obtained from chicken meat samples, of which 30.8% are biofilm producers and 69.2% are lectin producers. Lectin is purified 36.8-fold to final specific activity of 506.9 U/mg. Four nanoparticle types are prepared via laser ablation: platinum (Pt), gold (Au), silica oxide (SiO₂ ), and tin oxide (SnO₂ ). The four types are characterised, and pulse feeding is used to conjugate the lectin and nanoparticles. Pt, Au, SiO_2, and SnO₂ nanoparticles inhibit biofilm formation, especially SiO₂ nanoparticles, which have higher effectiveness when conjugated with purified lectin. SiO₂ -conjugated lectin significantly (p < 0.05) inhibits biofilm formation more effectively than control and other nanoparticle-conjugated lectins. Au-, Pt nanoparticle-, and SnO₂ -conjugated lectins inhibit biofilm significantly compared with control (p < 0.05), and rhlR gene expression is decreased in the presence of SiO₂ -conjugated lectin. Furthermore, lectin and Pt, Au, SiO₂ and SnO₂ nanoparticles separately, and their conjugated lectins, are effective biofilm inhibitors. Of these, SiO₂ -conjugated lectin was most significant as an anti-biofilm. Moreover, virulence factors regulon and RhlR were reduced by SiO₂ -conjugated lectin, indicating that this conjugation may also decrease the virulence of P. aeruginosa.