Facile green synthesis of baicalein fabricated gold nanoparticles and their antibiofilm activity against Pseudomonas aeruginosa PAO1

- Phytocompound, baicalein was employed for ecofriendly synthesis of Baicalein coated gold nanoparticles (BCL-AuNPs).
- BCL-AuNPs were characterized using UV-Vis spectroscopy, FTIR spectroscopy, TEM and DLS.
- The synthesized BCL-AuNPs were found to be predominantly spherical in shape with an average size of 26.5 nm.
- A significant decrease in biofilm formation and EPS production was observed in P. aeruginosa on treatment with sub-MIC of BCL- AuNPs.
- The 3D images of the biofilm and Z-stacks clearly revealed the the decrease in the thickness of biofilm.

Biofilm formation is one of the major problems associated with chronic diseases and also attributes for the antibiotic resistance in bacteria. In recent times nanoparticles have been utilized to improve the efficacy of the existing antimicrobial and anti-biofilm agents. The ease in functionalization of gold nanoparticles (AuNPs) makes them a potential carrier for antimicrobial agents. However, the use of physical or chemical methods of the production of nanoparticles is expensive, labour intensive and hazardous to ecosystem. On the other hand, the use of plant based compounds serve as an eco-friendly way for the synthesis of nanoparticles with improved biocompatibility and therapeutic applicability. In the present study, phytocompound, baicalein was used as a reducing and capping agent for the synthesis of spherical shape AuNPs. The baicalein decorated gold nanoparticles (BCL-AuNPs) were characterized and evaluated for their anti-biofilm efficacy against Pseudomonas aeruginosa PAO1. The biosynthesized BCL-AuNPs was characterized using UV-Visible spectra, Dynamic Light Scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Diffraction (EDAX), and High Resolution Transmission Electron Microscopy (HR-TEM). The biosynthesized BCL-AuNPs were determined to be spherical in shape with an average size of 26.5 nm. The sub-MIC concentration of BCL-AuNPs exhibited significant anti-biofilm activity against P. aeruginosa PAO1. On treatment with BCL-AuNPs (100 g mL−1), a reduction in biofilm formation by 58.74 ± 5.8% and 76.51 ± 4.27% was observed in microtiter plate assay and tube method, respectively. A significant reduction in exopolysaccharide (EPS) production by 81.29± 2.96% was observed. The swimming and swarming motility were also effectively arrested in presence of BCL-AuNPs. Further, Light microscope and CLSM studies were carried out to examine the effect of BCL-AuNPs on the surface topography and architecture of P. aeruginosa biofilm. Thus, the present study suggests the potential use of BCL-AuNPs in the development of novel therapeutics for the prevention and treatment of biofilm associated chronic infections.

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