To remove any free biomass residue or compound that is not the capping ligand of the
nanoparticles, the residual solution of 30 ml after reaction was centrifuged at 10000 rpm for 10
min and the resulting suspension was redispersed in 2 ml sterile distilled water. The centrifuging
and redispersing process was repeated three times. Thereafter, the purified suspension was freeze
dried to obtain dried powder. Finally, the dried nanoparticles were analyzed by FTIR Nicolet
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