The chemical compositions of the alcohol insoluble residues (AIRs)
from fresh, freeze dried and dehydrated aloe vera parenchyma
has been characterized by Femenia and co-workers [26] and the
results are shown in Table 1. Since 99% of aloe vera fresh gel is
water and its ability to associate with metal ions in solution, aloe
vera stable gel may be used as a bio-reducing agent in the
preparation of metal and oxide precursor powders. Recently, the
extract of aloe vera plant has been successfully used to synthesize
single crystalline triangular gold nanoparticles (50–350 nm in
size) and spherical silver nanoparticles (15 nm in size) in high
yield by the reaction of aqueous metal source ions (chloroaurate
ions for Au and silver ions for Ag) and the extract of the aloe vera
plant [27]. Most recently, Maensiri et al. reported for the first time
the synthesized nanoparticles of In2O3 by simple method using
aloe vera plant extract solution [28]. To the best of our knowledge,
this biosynthesis route has not been extended to the preparation of
HAp.