Carica papaya peel mediated synthesis of silver nanoparticles and its antibacterial activity against human pathogens

Abstract

Metallic nanoparticles are traditionally synthesized by wet chemical techniques, in which the chemicals used are quite often toxic and flammable. Ripe carica papaya peel is found to be a suitable source for green synthesis of silver nanoparticles. In the present work, a cost effective and environmental friendly technique for the green synthesis of silver nanoparticles from 1 mM silver nitrate (AgNO 3) solution through the extract of ripe Carica papaya peel of various concentrations (5 ml, 10 ml, 15 ml, 20 ml, 25 ml) is described. The synthesized silver nanoparticles are characterized by using the UV-vis absorption spectroscopy, FT-IR, XRD, SEM and TEM. The formation of silver nanoparticles is confirmed by surface plasmon resonance, determined by UV-vis spectra at 400-435 nm. The shift in the absorption bands and variation in the calculated optical band gaps for the various concentrations of papaya peels extracts are also observed. The FT-IR spectra reveal that an increase in the concentration of the papaya peel extract shifts the bands to higher wavelengths. The average crystallite size for various concentrations of papaya peel extract is observed from XRD spectral analysis and is found to be around 16-20 nm, which is in good agreement with the TEM analysis. The SEM analysis shows the spherical structure of the silver nanoparticles with some agglomeration for higher concentrations of papaya peel extract. The synthesized silver nanoparticles show good antibacterial activity against human pathogens such as Escherichia coli and Staphylococcus aureus and it has many medical applications.

Biogenic synthesis of silver nanoparticles using S1 genotype of Morus alba leaf extract: characterization, antimicrobial and antioxidant potential assessment

“…The broad and low intensity SPR band at high concentration appeared because of sedimentation of particle with time. Similar result was also reported by Balavijayalakshmi and Ramalakshmi [54] using Carica papaya peel. Nanosilver formed with 10 −2 M and 10 −3 M silver nitrate showed maximum wavelength peak at ~ 450 nm and ~ 435 nm respectively, indicating red shift with increase in concentration.…”

Role of Ribes khorassanicum in the biosynthesis of AgNPs and their antibacterial properties

“…The band in 1719 cm −1 seem to be assigned for C–C (ν st. ; non‐conjugated), while a band in 1607 cm −1 correlates to C = O (ν st. ; amide) [41]. The peak of C = C group (at 1398 cm −1 ) absent for AgNPs is possible, due to the reduction of Ag + to Ag° [42]. The peak at 1070 cm −1 , which is absent for the AgNPs FT‐IR spectrum, is the bending vibration of the C–O stretch and could be due to the stabilisation of AgNPs through this group [43].…”

Biosynthesis of silver nanoparticles using Malva parviflora and their antifungal activity

“…The chemical composition of the LEMP acted as an electron donor and mediated the reduction of silver ions that resulted in synthesis of AgNPs, further the surface plasmon resonance (SPR) phenomena causes the change in color to reddish-brown ( Shankar et al, 2003 , Fan et al, 2009 ) The synthesis of AgNPs was affirmed by the UV–vis spectroscopy through the recognition of the SPR property by absorption spectra band ( Zhang et al, 2016 ). The absorption peak depends on the characteristics of the biochemicals of the plant extracts and the concentration used for the AgNPs synthesis ( Balavijayalakshmi and Ramalakshmi, 2017 , Kumar et al, 2017 , Yasir et al, 2017 ). Whereas, the FT-IR analysis ascertain the presence of several functional groups in the solution of the biosynthesized AgNPs .…”