Development data associated with effects of stiffness softening of 3D-TIPS elastomer nanohybrid scaffolds on tissue ingrowth, vascularization and inflammation in vivo

This DiB article contains data related to the research article entitled “Cellular responses to thermoresponsive stiffness memory elastomer nanohybrid scaffolds by 3D-TIPS” (Wu et al., 2018). Thermoresponsive poly (urea-urethane) nanohybrid elastomer (PUU-POSS) scaffolds were implanted in rats for up to 3 months. The porous structure and tensile mechanical properties of the scaffolds are listed and compared before and after in vitro and in vivo tests. The details of the histological analysis of the explants with different initial stiffness and porous structures at various time points are presented. The images and data presented support the conclusion about the coupled effects of stiffness softening and the hierarchical porous structure modulating tissue ingrowth, vascularization and macrophage polarization in the article (Wu et al., 2018).


Value of the data
Data presented in this article provide direct comparison of the stiffness softening and hierarchical structure of the 3D-TIPS scaffolds before and after in vitro and in vivo tests. The data magnify more insights about the changes of structures at multi-scales and mechanical properties of the scaffolds under biophysical and biological conditions.
The histological images of the scaffolds with different initial stiffness and porous structure by immunohistochemistry elucidate for the first time how the stiffness softening and digitally printed hierarchical porous structure regulate tissue ingrowth, vascularization and macrophage polarization towards an M2 phenotype at the early (week 4) and late (week 12) stages in vivo. Table 1 shows the stiffness softening effect of the scaffolds in vitro over day 0-28 and how they relax towards their intrinsic elasticity. The dimensions of the 3D printed preforms and the scaffolds as produced are shown in Table 2. Table 3-7 show the effects of softening during in vivo implantation at various time points, in terms of tensile mechanical properties and XRD characterization respectively. Figs. 1-3 depict low and high magnification of Hematoxylin and Eosin (H&E) and Masson's trichrome (M&T) staining showing collagen fibre orientation and tissue ingrowth within the explants. Table 8 quantifies the angiogenic response of the explants during implantation time with stiffness softening. The softening effects on macrophage polarization (M1 markers CD86, CD63 and M2 maker CD163) and T-cell response (markers CD3 and CD4) are quantified in Tables 9-15; Table 7 Analysis of WAXD spectra of the explants during implantation. Degree of crystallinity (Dc, %), d-spacing (d, A) of semicrystalline structure and broad halo peaks of amorphous structures.

Table 8
Proportion of total tissue/scaffold volume occupied by blood capillaries at weeks 4, 8 and 12. Immunofluorescent staining of anti-CD31 marker for blood capillaries.

Fabrication of thermoresponsive PUU-POSS scaffolds
A 3D-TIPS technique, based on reverse 3D printing and phase separation of the polymer solution, as described in [1], was used to manufacture PUU-POSS scaffolds (50% infill density) at different thermal conditions (50CC, 50CC þH and 50RTC þH).

Characterization of the scaffolds prior to implantation
An Instron 5655 was applied to test static tensile mechanical properties of the scaffolds, before and after incubation over 28 days at body temperature, as described in [1], as well the explants after implantation in rats for 4, 8 and 12 weeks. The dimensions of the printed preforms and the scaffold as produced were also measured and estimated.

Characterization of the scaffold explants
As detailed in [1], the scaffolds were subcutaneously implanted in adult male rats and harvested at different time points. The physico-mechanical properties (i.e. tensile properties and phase structure) were then analyzed with an Instron 5655 tester and an X-ray diffractometer. Sectioning and histological staining (i.e. H&E and M&T) were carried out, and collagen fiber formation and tissue ingrowth orientation was quantified as previously described [1]. Immunofluorescent staining against capillary marker CD31, macrophage markers CD86/CD68/CD163 and T-cell makers CD3/CD4 was carried out, and the number of positive stained cells was quantified as described in [1].