Comparative Evaluation of Antibacterial Efficacy of Biological Synthesis of ZnO Nanoparticles Using Fresh Leaf Extract and Fresh Stem-Bark of Carica papaya

Droepenu Eric Kwabena,Asare Ebenezer Aquisman,Kuan Ying Kok,Zaini Bin Assim,Chin Suk Fun,Boon Siong Wee

doi:10.5101/nbe.v11i3.p264-271

Abstract

The study compared the antibacterial activity of synthesized ZnO nanoparticles (NPs) from fresh leaf and fresh stem bark aqueous extracts of Carica papaya against five selected microbes: Staphylococcus aureus, (Gram positive (+ve)), Escherichia coli (Gram negative (–ve)), Acinetobacter baumanni (Gram–ve), Exiguobacterium aquaticum (Gram+ve), and Klebsielia pneumonia (Gram +ve). The morphological features of the biosynthesized ZnO NPs were analyzed using transmission electron microscope (TEM) and scanning electron microscope (SEM); the Fourier-transform infrared spectrometer (FTIR) technique was used to observe the surface functional groups. The experimental results indicated that ZnO NPs were successfully synthesized using modified hydrothermal technique, which showed agglomerated flake-like or petal-like shapes with the organic extract surrounding the formed particles. The average particle size of the synthesized ZnO nanoparticles determined by SEM ranged between 54-97 nm with the width and length of the petal-like structures been 30 nm and 62 nm respectively. The average ZnO NPs from fresh stem bark extract of Carica papaya with higher concentrations (100-1000 ppm) demonstrated a higher antibacterial activity than the fresh leaf extracts. On the other hand, ZnO NPs from fresh leaf extracts of lower concentrations (25-50 ppm) rather showed a suitable result than the fresh stem bark. In general, ZnO NPs showed a positive antibacterial result towards the selected microbes. This shows that, the synthesized ZnO NP can be a substitute to chemical methods.

Highlights

Current development in science and technology has shot nanotechnology into the limelight as a field blending material science, bio-nanoscience, and technology [1] together
In determining the morphology of the synthesized Zinc oxide (ZnO) particles, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques were used for the analysis
From the images of the bio-synthesized ZnO nanoparticles for fresh leaf and fresh stem back aqueous extracts of Carica papaya (Fig. 1(a)-(d)), flake-like or petal-like shapes were recorded which corresponded to a study by Gopal and Kamila [18]

Summary

Introduction

Current development in science and technology has shot nanotechnology into the limelight as a field blending material science, bio-nanoscience, and technology [1] together. No research regarding the biological synthesis of ZnO nanoparticles had used fresh leaf extract and fresh stem-bark of Carica papaya.

Results

Conclusion