Human dental pulp progenitor cell behavior on aqueous and hexafluoroisopropanol based silk scaffolds

Abstract

Silk scaffolds have been successfully used for a variety of tissue engineering applications due to their biocompatibility, diverse physical characteristics, and ability to support cell attachment and proliferation. Our prior characterization of 4-day postnatal rat tooth bud cells grown on hexafluoro-2-propanol (HFIP) silk scaffolds showed that the silk scaffolds not only supported osteodentin formation, but also guided the size and shape of the formed osteodentin. In this study, interactions between human dental pulp cells and HFIP and aqueous based silk scaffolds were studied under both in vitro and in vivo conditions. Silk scaffold porosity and incorporation of RGD and DMP peptides were examined. We found that the degradation of aqueous based silk is much faster than HFIP based silk scaffolds. Also, HFIP based silk scaffolds supported the soft dental pulp formation better than the aqueous based silk scaffolds. No distinct hard tissue regeneration was found in any of the implants, with or without additional cells. We conclude that alternative silk scaffold materials, and hDSC pre-seeding cell treatments or sorting and enrichment methods, need to be considered for successful dental hard tissue regeneration.

Dental cell sheet biomimetic tooth bud model

“…To date, our group has been using tissue engineering approaches to identify optimal scaffold materials and designs that promote dental epithelial (DE) and mesenchymal (DM) cell interactions leading to replacement tooth formation [4, 12, 13]. For the study presented here, we have used DE and DM progenitor cells isolated from un-erupted molar tooth buds extracted from 5–6 month old porcine jaws, which consisted of enamel organ, dental papilla, and dental follicle tissues and cells.…”

“…The progenitor DE cells generated in this manner will differentiate into enamel forming ameloblasts, while the DM cells will give rise to odontoblasts, dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), stem cells from apical papilla (SCAP) and dental follicle precursor cells (DFPCs) [17]. In many instances, our prior published reports have shown that instead of creating bioengineered teeth that adopted the size and shape of the scaffold, we observed that many small tooth crowns formed throughout the implant, suggesting that these models lacked the proper ECM molecule gradients present in naturally formed teeth, which provide essential cues for proper tooth development, and for periodontal tissue and surrounding alveolar bone formation [4, 12, 13, 15]. …”

Silk scaffolds for dental tissue engineering

“…Also, co-culture of osteoblasts and endothelial cells on SF nets has been shown to support the formation of microvessel-like structures even without fi bronectin coating and pro-angiogenic factors (Unger et al, 2007). Zhang et al (2011) investigated the interactions between human dental pulp cells and hexafl uoro-2-propanol (HFIP) silk scaffolds both in vitro and in vivo . They found that HFIP based silk scaffolds supported the soft dental pulp formation better than the aqueous based silk scaffolds.…”

Progress in Bioengineered Whole Tooth Research: from Bench to Dental Patient Chair

“…Hydrogel based materials such as collagen, gelatin, and alginate are highly tunable, and have been used to successfully bioengineer various dental tissues [21, 22, 32, 52]. Silk-based materials have also shown promise in providing an environment that can support osteo-dentin like mineralized tissue formation, but further optimizations are needed to enhance bioengineered dental tissue formation [53, 54]. A combination of these and other novel materials may eventually be used to successfully engineer the wide variety of hard and soft tissues that comprise the natural tooth.…”