5. Subcutaneous transplantation of 3D-printed scaffold
Since the in vivo assessment of a potential biomaterial is
focused on clinical applications, it must be noted that the developed
biomaterial should be considered biocompatible without toxicity or any
other adverse clinical effects after interaction
within the living systems. During the in vivo implantation study,
the materials were subcutaneously implanted into the back of the
experimental rats under anaesthesia. None of the rats displayed visible
signs of inflammation (such as redness, heat, swelling, pain, loss of
appetite, and reduced mobility) during the post-implantation period.
Surgical sites on all animals appeared normal post-implantation. Upon
collecting the samples, no apparent tissue hyperplasia and suppuration
were noted in the area surrounding the implant, and no apparent immune
rejection reaction was noted between the surrounding tissues and the
material (Figure 15).
The tissues collected from animals 2 weeks after the implantation were
sectioned and stained with H&E to investigate the cellular inflammatory
response to the implanted materials (Figure 16). Comparison between
freeze-drying and oven-drying processes revealed no significant
difference in the inflammatory status in this study, indicating no
effect of the drying preparation method used. The histological sections
of the K group were characterised by a large number of inflammatory
cells. Some abscess areas were noted. Inflammation was found to be
severe, with a large number of neutrophils. The kc group showed marked
inflammatory and cellular changes in the epidermis in the presence of
neutrophils and mononuclear cells along with oedematous eosinophilic
exudate. Moreover, inflammation was nonsignificant or moderate in most
sections. The HE-stained sections confirmed the biocompatibility of the
ks group with the connective tissues. At day 14, small areas exhibited
neutrophil regions. Inflammation was nonsignificant in most sections.