Synthesis of Biogenic Silver Nanoparticles Using Caesalpinia digyna and Investigation of Their Antimicrobial Activity and in Vivo Biocompatibility

Mahruba Sultana Niloy, Md Monir Hossain, Masato Takikawa, Md Salman Shakil, Shakil Ahmed Polash, Kazi Mustafa Mahmud, Md Forhad Uddin, Morshed Alam, Razib Datta Shubhra, Mohammad Mahfuz Ali Khan Shawan, Tanushree Saha, Shinji Takeoka, Md Ashraful Hasan*, Satya Ranjan Sarker*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Among metallic nanoparticles, silver nanoparticles (AgNPs) have a wide spectrum of medical applications. Herein, biogenic silver nanoparticles (bAgNPs) were prepared from extracts of Caesalpinia digyna leaf as a reducing agent at different pH values (i.e., 5, 7, 8, and 10). The as-synthesized bAgNPs were characterized using UV-vis and Fourier transform infrared (FTIR) spectroscopies, scanning transmission electron microscopy, powder X-ray diffraction analysis, dynamic light scattering, and ζ-potential analysis. The sizes of bAgNPs prepared at pH 5, 7, 8, and 10 were 45.4, 11.3, 11.4, and 40.8 nm, respectively, and all of the nanoparticles were negatively charged. The antimicrobial activity of the as-prepared bAgNPs was investigated against Bacillus subtilis, Escherichia coli DH5α, E. coli K12, enteropathogenic E. coli (EPEC), and Salmonella typhi. The bAgNPs prepared at pH 8 showed the highest antibacterial propensity against all of the bacterial strains as exhibited in the zone of inhibition (ZOI) as well as the CellTox green assay, which can be due to their relatively small size, stability, and higher surface area-to-volume ratio. The bAgNPs synthesized at pH 8 showed the highest ZOI against B. subtilis, which was â25 mm in diameter. The lipid peroxidation assay demonstrated the formation of the malondialdehyde-thiobarbituric acid (MDA-TBA) adduct while treating the bacteria with bAgNPs due to the oxidation of fatty acids present in the membrane. The highest amount of MDA-TBA adduct was observed when Gram-positive B. subtilis was exposed to bAgNPs. On the contrary, rats treated with bAgNPs demonstrated no significant toxicity in terms of hematological and biochemical parameters. The bAgNPs also showed excellent compatibility with human red blood cells. Overall, bAgNPs synthesized at pH 8 have superior antimicrobial activity and excellent biocompatibility and, therefore, can be used as potential antibacterial agents.

Original languageEnglish
Pages (from-to)7722-7733
Number of pages12
JournalACS Applied Bio Materials
Issue number11
Publication statusPublished - 2020 Nov 16


  • Caesalpinia digyna
  • antibacterial activity
  • biocompatibility
  • biogenic AgNPs
  • lipid peroxidation assay

ASJC Scopus subject areas

  • Biochemistry, medical
  • General Chemistry
  • Biomedical Engineering
  • Biomaterials


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