Silk fibroin gellan-gum spongy-like hydrogels regulate biomineralization of hydroxyapatite

In nature, the highly dynamic yet well-regulated process of biomineralization is employed by many living organisms to develop functional structures such as shell, bone, teeth enamel and others. Biomineralized materials envision as alternative choice for bone tissue engineering due to the similarity with native bone. Strategic use of organic-template to regulate the growth of inorganic hydroxyapatite crystals (HAp) is one of the approaches in biomimetic research.^1,2 However, the optimization of biomineralization process is difficult because of complex interplay among chemistry-architecture-mechanics. Utilizing biomimetic method and calcium chloride as reagent, the growth of HAp crystals is reported in gellan-gum spongy-like hydrogels in presence of silk fibroin (SEM-EDS and Alzarin Red S). Osteogenic mineralization by human adipose stem cells is assessed in response to hydrogel composition-structure. Changes in fibroin-gellan gum ratio has little effect on cellular mineralization but influence greatly the osteogenic gene expression (osteopontin and osteoprotegerin). Increasing amount of silk fibroin also enhances the collagen production and HAp crystallization. The results indicate the influence of hydrogel chemistry on HAp mineralization, which further can contribute to osteogenic gene-expression.

Acknowledgement: This work is supported by the European Union Framework Programme for Research and Innovation Horizon 2020 under grant agreement nº 668983 — FoReCaST. VM Correlo acknowledges Investigator FCT program (IF/01214/2014) and JM Oliveira to the program Investigador FCT2015 (IF/01285/2015).

Reference:

1. Jin et al., Colloids and Surfaces B: Biointerfaces 2015;134:339–45.
2. Lett et al., RSC Adv. 2019;9:6228-40.