Table 1.
Collagen mineralization in collagen‐based natural materials
| Bone (vertebrates) | Tooth (vertebrates) | Spicules (sponges) | |
|---|---|---|---|
| Mineral | HAp | HAp | Amorphous Silica |
| Ratio organic:inorganic | 35:65 wt% | 35:65 wt% (cementum) 30:70 wt% (dentin) | n.a. a) |
| Ratio extra‐:intrafibrillar (inorganic content) | 75:25 vol% | 75:25 vol% (cementum) 65:35 vol% (dentin) | n.a. a) |
| Mineral size b) | (2–7) nm × (15–200) nm × (10–80) nm c) | (2–7) nm × (15–200) nm × (10–80) nm d) | n.a. a) |
To the best of our knowledge, collagen has been found to template silica formation only in the hexactinellida sponges Hyalonema sieboldii.[ 4 ] The slow‐etched method developed by Ehrlich et al. allowed the authors to obtain and characterize the collagen‐like molecule that templates silica deposition but no details regarding organic–inorganic ration or the location of the minerals are given. In other hexactinellida and demosponges, fibrillar collagen is found as a net that surrounding the spicules
Mineral size is given in (thickness) × (length) × (width)
The size of HAp crystals in bone varies among species, age, and different regions of bone. Size of extrafibrillar crystals is comparable to the size of intrafibrillar crystals
The HAp crystals in dentin are platelet‐shaped in dentin and are more needle‐shaped toward the pulp. Size of extrafibrillar crystals is comparable to the size of intrafibrillar crystals.