Ultrasonication assisted fabrication of l-lysine functionalized gadolinium oxide nanoparticles and its biological acceptability.

Gadolinium oxide nanoparticles (GdO) have recently gained attention due to their diverse bio-applications. However, their functionalization with amino acids has not been reported yet to the best of our knowledge. In the present report, the potential of sonication technique (for the first time to the best of our knowledge) in the fabrication of GdO nanoparticles was explored. Sonication is an efficient technique for the synthesis of evenly dispersing nanoparticles in liquids thus, the present report highlights the use of ultrasonication technique for the fabrication of uniform 2 nm sized luminescent l-lysine coated gadolinium oxide nanoparticles (l-lysine@GdO). Investigation of l-lysine conjugation with nanoparticles was confirmed by FT-IR, Differential Scanning Calorimetric analysis and Zeta potential. The interactions of serum protein (BSA) with synthesized nanoparticles have been explored using UV-visible spectroscopy, Fluorescence spectroscopy and Circular Dichroism (CD). The synthesized l-lysine coated nanoparticles demonstrated potential for antimicrobial and antifungal agents, which has been tested against two bacterial strains Escherichia coli and Staphylococcus aureus and two antifungal Candida albicans and Candida glabrata cells. The minimal inhibition concentrations (MIC) of nanoparticles against E.coli and S. aureus are 8 µg mL-1 and 16 µg mL-1, respectively. The cell viability, MTT assay on HaCaT cell lines revealed the non-toxicity of synthesized nanoparticles.