Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Jul 7:8:743.
doi: 10.3389/fbioe.2020.00743. eCollection 2020.

Overcoming the Design Challenge in 3D Biomimetic Hybrid Scaffolds for Bone and Osteochondral Regeneration by Factorial Design

Affiliations

Overcoming the Design Challenge in 3D Biomimetic Hybrid Scaffolds for Bone and Osteochondral Regeneration by Factorial Design

Alessandra Dellaquila et al. Front Bioeng Biotechnol. .

Abstract

Scaffolds for bone regeneration have been engineered by a plethora of manufacturing technologies and biomaterials. However, the performance of these systems is often limited by lack of robustness in the process design, that hampers their scalability to clinical application. In the present study, Design of Experiment (DoE) was used as statistical tool to design the biofabrication of hybrid hydroxyapatite (HA)/collagen scaffolds for bone regeneration and optimize their integration in a multilayer osteochondral device. The scaffolds were synthesized via a multi-step bioinspired process consisting in HA nano-crystals nucleation on the collagen self-assembling fibers and ribose glycation was used as collagen cross-linking method to modulate the mechanical and physical properties. The process design was performed by selecting hydrogel concentration, HA/collagen ratio and cross-linker content as key variables and the fabrication was carried out basing on a full factorial design. Scaffold performances were tested by evaluating porosity, swelling ratio, degradation rate and mechanical behavior as model output responses while physicochemical properties of the constructs were evaluated by TGA, ICP, FT-IR spectroscopy, and XRD analysis. Physicochemical characterizations confirmed the nucleation of a biomimetic inorganic phase and the interaction of the HA and collagenic components. The DoE model revealed a significant interaction between HA content and collagen cross-linking in determining porosity, swelling and mechanical properties of the scaffolds. The combined effect of hydrogel concentration and mineral phase played a key role on porosity and swelling while degradation resulted to be mainly affected by the HA loading and ribose content. The model was then used to determine the suitable input parameters for the synthesis of multi-layer scaffolds with graded mineralization rate, that can be used to mimic the whole cartilage-bone interface. This work proved that experimental design applied to complex biofabrication processes represents an effective and reliable way to design hybrid constructs with standardized and tunable properties for osteochondral tissue engineering.

Keywords: biomineralization; collagen cross-linking; factorial design; hybrid scaffold; osteochondral regeneration.

PubMed Disclaimer

Figures

FIGURE 1
FIGURE 1
Hydrogel concentration for low (0.25 min) and high (5 min) vacuum time levels, calculated as the ratio between the scaffold weight after freeze-drying and the HA/Collagen wet slurry.
FIGURE 2
FIGURE 2
Synthesis of HA/Collagen scaffolds. (A) Collagen biomineralization through neutralization process, (B) MgHA/Collagen slurry glycation with ribose (only for the scaffolds formulations F5–F8), and (C) vacuum filtration and scaffold freeze-drying.
FIGURE 3
FIGURE 3
(A) Representative TGA curves of the formulations HA/collagen 70/30 wt. % and 30/70 wt. % (F1 and F7) and (B) average data of the HA and collagen mass fractions (wt. %).
FIGURE 4
FIGURE 4
FTIR spectra of (A) the formulations HA/collagen and (B) the formulations HA/collagen after ribose cross-linking.
FIGURE 5
FIGURE 5
XRD patterns of (A) formulations F1–F4 (2 h of HA maturation time, no ribose cross-linking) and (B) formulations F5–F8 (5 days of HA maturation time, ribose cross-linking).
FIGURE 6
FIGURE 6
Average values of (A) Porosity, (B) Swelling Ratio, (C) Degradation Rate, and (D) Compressive Modulus for the eight scaffold formulations.
FIGURE 7
FIGURE 7
Interaction plots for (A) Porosity, (B) Swelling Ratio, (D) Compressive Modulus, and (C) Main plot for Degradation (data from the reduced model).
FIGURE 8
FIGURE 8
Contour plots for (A) Porosity, (B) Swelling Ratio, and (C) Compressive Modulus.

Similar articles

Cited by

References

    1. Anseth K. S., Bowman C. N., Brannon-Peppas L. (1996). Mechanical properties of hydrogels and their experimental determination. Biomaterials 17 1647–1657. 10.1016/0142-9612(96)87644-7 - DOI - PubMed
    1. Armiento A. R., Stoddart M. J., Alini M., Eglin D. (2018). Biomaterials for articular cartilage tissue engineering: learning from biology. Acta Biomater. 65 1–20. 10.1016/j.actbio.2017.11.021 - DOI - PubMed
    1. Bahçecitapar M., Karadağ Ataş Ö., Aktaş Altunay S. (2016). Estimation of sample size and power for general full factorial designs. Ýstatistikçiler Derg. Ýstatistik Aktüerya 9 79–86.
    1. Belbachir K., Noreen R., Gouspillou G., Petibois C. (2009). Collagen types analysis and differentiation by FTIR spectroscopy. Anal. Bioanal. Chem. 395 829–837. 10.1007/s00216-009-3019-y - DOI - PubMed
    1. Bhattacharjee M., Coburn J., Centola M., Murab S., Barbero A., Kaplan D. L., et al. (2015). Tissue engineering strategies to study cartilage development, degeneration and regeneration. Adv. Drug Deliv. Rev. 84 107–122. 10.1016/j.addr.2014.08.010 - DOI - PubMed

LinkOut - more resources