Next, FTIR spectra of nHAp, chitosan and nHApCs were
measured (see Fig. 3) to further confirm the deposition of these
materials. A typical FTIR for chitosan is depicted in Fig. 3a.The
signals at 3421 cm1 corresponding to stretching (–NH), 2900 and
1388 cm1 corresponding to stretching and bending (–CH) group
respectively, 1643 cm1 for (C–N) group, and 1039 cm1 for
stretching (C–O–C) group. On the other hand, the nHAp spectrum
(Fig. 3b) displays signals at 3450 and 1643 cm1 were assigned to
stretching (s) and bending (b) hydroxyl group, respectively. The
absorption bands observed at 1036 and 865 cm1 were assigned to
asymmetric stretching (as) while those at 602 and 566 cm1 for
symmetric stretching of phosphate group. The signals of nHAp/Cs
composite coincided at a great extent with the major absorbance
signals of nHAp. However, the signals at 2900 and 1388 cm1
corresponding to stretching and bending (–CH) group appeared in
the nHAp/Cs complex verifying its formation (see Fig. 3c).
On the other hand, the zeta-potential measurements for nHAp
and nHApCs (Fig. 4) revealed a PZC at pH of 7 and 8 for nHAp and
nHApCs, respectively. This means that at pH lower than 7, both of
nHAp and nHApCs will carry positive charges and above pH of 8,
both will carry a negative charge. However, in between (pH = 7–8),